Radiology Notes Monday, August 19, 2013 2:37 PM
http://fitsweb.uchc.edu/student/rad http://fitsweb.uchc.edu /student/radiology iology http://www.med-ed.virginia.edu/courses/rad/index.html http://www.radiologyassistant.nl/en/p497b2a265d96d/ches http://www.radiologyassis tant.nl/en/p497b2a265d96d/chest-x-ray-basic-in t-x-ray-basic-interpretation.html#in514d80fcb1408 terpretation.html#in514d80fcb1408
http://www.stritch.luc.ed http://w ww.stritch.luc.edu/lumen/Me u/lumen/MedEd/Radio/curricu dEd/Radio/curriculum/Medicine/Pl lum/Medicine/Pleural_effusion1.h eural_effusion1.htm tm TEST
2 hours - 80 questions questions
Management, next step, cases with images, just an image
Images repeated on exam that we saw in class
Introduction to Radiology/Imaging Plain Film
Plain x-ray is a 2D representation of a 3D object. Only when you see the object in two planes can you see what something is and define define it’s true shape
X-rays have 5 tissues you can identify based on absorption coefficient; need difference in absorption coefficient of 5% o
Air (black): photo does right through and doesn’t get absorbed; -1000
o
Water, muscle, blood, soft tissue (gray)
o
Fat (dark gray)
o
Bone (white): calcium
o
Metal (white); +1000
Brightness on x-ray: lead > barium > bone > muscle/blood > liver > fat > air Normal chorinal angle is about 70 degrees. There are subchorinal LNs which can elevate the main stem bronchus
PA vs. AP – AP – always always labeled by direction of path of beam (supine is AP, anterior to posterior)
Collimator – lead – lead square used to limit boundaries of x-ray beams; triangulation: use images with history and physical
Too much light = over exposed, so looks black; not enough light = underexposed (energy can’t quite penetrate)
o
routine lateral is called left lateral, beam goes from righ t to left
MRI
Non-ionizing radiation, Great for looking at soft tissues
Contraindication with pacemakers/ferromagnetic devices
T1 - fluid is black black
T2- fluid is white
Fluoroscopy
Continuous stream of x-ray x-ray to watch what’s going on in real time; can watch motion
Downside is higher dose of radiation
Can use with contrast agents o
Inulin gets picked up by the kidney; Intravenous Pyelogram = inulin tagged with iodine
CT
X-ray in thin slices; very sensitive; each line = ray; 1000 slices of 1 mm cuts
Each slice has three dimensions
Orient yourself look at patient’s feet, upward
Nuclear Imaging
Outgrowth of Manhattan project (development of first atomic bomb)
Radiation with alpha/beta/gamma
PET (Positron Emission tomography) scan: tag positron with glucose and look for metabolically active tumors o
Hope is to one day tag it so it can destroy these areas
Ultrasound
High frequency sound waves in water (know speed of sound in water) No ionizing radiation, relatively inexpensive, real time evaluation, can utilize color Doppler to look at flow Applications: liver, gallbladder, biliary system, kidney; terrible with bowel
Radiation Dangers and Protection
Unit of energy in x-ray is called a Rad
Sievert is the amount of radiation a particular unit of tissue receives
For the average CT of chest or abdomen, dose is 10-15 milliSieverts (CXR is .01 mSv)
o
Difference in absorption in different types of tissue
o
CTA is 15-20 milliSieverts
o
Average CXR is 0.01 milliSieverts
o
10milliSieverts = 1/1000 risk of developing cancer
o o
Abdominal CT scan: 1/143 risk Normal radiation from natural sources – sources – normally normally 1-3 mSv/year In areas of high background, 3-13 mSv/year
o
Over 50 mSv at one time is high risk for developing cancer
hydroxyl ion). This can potentially cause damage to your DNA. Photon can actually damage the DNA or break the strand if it hits it directly.
Optimization of protection by keeping exposure as low as reasonably achievable; dose limits for occupational people
Medical, occupational, and public exposures all exist
CHEST
40% of all imaging done in US are CXR
Adequate film: o
CXR ideally done in PA position, which is better for heart size (10-20% overestimation when do an AP). Done at 72 inches at maximal inspiration
o
Adequate inspiration: 9 posterior ribs on R side; if see 11-12 ribs, likely COPD
Normal heart should be less than 50% of cardiothoracic ratio 2nd anterior rib follow-up, corresponds to 2 nd posterior rib o
Non rotation: clavicles should be equidistant from clavicles If spinous process closer to left clavicle, then rotated left anterior oblique
o
Degree of penetration:
o
Routinely take left lateral (want heart on left side of chest closest to the film)
densitometer, vertebral bodies through the density of heart, pu lm vascularity to LLL through heart
Systematic Approach o
Bony framework structures: cervical spine, clavicles, AC joint and acromion, scapula, glenoid, coracoid process, humeral head, ribs, vertebrae, pedicl es (will often see Bony structures: metastatic disease here)
o
Soft tissues
o
Lung fields and hila (see his tutorial)
tissue: calcification of carotid, LN calcification, masses, abdomen, stomach bubble, splenic f lexure, neck and chest wall Soft tissue: Right upper, middle and lower lobes; left upper and lower lobes Left
The right lung comprises 10 segments: 3 in the right upper lobe (apical, anterior and medial), 2 in the rig ht middle lobe (me dial and lateral), and 5 in the
1 fissure- oblique oblique
right lower lobe (superior, medial, anterior, lateral, and posterior). Right
The left lung comprises 8 segments: 4 in the left upper lobe (apicoposterior, anterior, superior lingula, and inferior lingul a) and 4 in the left lower lobe
2 fissures
(superior, anteromedial, lateral, and posterior). TB likes posterior segment of upper lobe Immunocompromised- superior segment of lower lobe o
Diaphragm and pleural spaces
o
Mediastinum and heart
o
Abdomen and neck
o
Pit falls
– if left higher may have loss of lung volume (e.g. atelectasis) Right hemidiaphragm is higher than the left – if
Poor inspiration Over or under penetration Rotation
Lungs o
Upper, middle, lower lung field; hilar structures including PA and PV; pulmonary vascularity, diaphragm, costophrenic sulcus; right hemidiaphragm is usually higher than left
o
Carina
(if left higher, might be phrenic nerve palsy but most commonly loss of lung lung volume such as atelectasis; tumor). Then compar e one side to the other Look for lymph nodes in this area (e.g. stage 4 lung cancer, no longer operable) Si lh lho ue ue tt tt e/ e/S ttrru ccttu rree
Upper right heart border/ascending
C on on tta ac t wi th th L un ung
Anterior segment of RUL
aorta Right heart border
RML (medial)
Upp er er le le ft ft he he ar art bo bo rd rde r
An te te riri or or se se gm gm en en t o f L UL
Left heart border
Lingula (anterior)
Aortic knob
Apical portion of LUL (posterior)
A nt nt er er io io r he he mi mi di di ap ap hr hr ag ag ms ms
(right anterior oblique = left posterior oblique) Medial segment of middle lob abuts the heart
L ow owe r lo lo be be s (a (a nt nt er er io io r) r)
hydroxyl ion). This can potentially cause damage to your DNA. Photon can actually damage the DNA or break the strand if it hits it directly.
Optimization of protection by keeping exposure as low as reasonably achievable; dose limits for occupational people
Medical, occupational, and public exposures all exist
CHEST
40% of all imaging done in US are CXR
Adequate film: o
CXR ideally done in PA position, which is better for heart size (10-20% overestimation when do an AP). Done at 72 inches at maximal inspiration
o
Adequate inspiration: 9 posterior ribs on R side; if see 11-12 ribs, likely COPD
Normal heart should be less than 50% of cardiothoracic ratio 2nd anterior rib follow-up, corresponds to 2 nd posterior rib o
Non rotation: clavicles should be equidistant from clavicles If spinous process closer to left clavicle, then rotated left anterior oblique
o
Degree of penetration:
o
Routinely take left lateral (want heart on left side of chest closest to the film)
densitometer, vertebral bodies through the density of heart, pu lm vascularity to LLL through heart
Systematic Approach o
Bony framework structures: cervical spine, clavicles, AC joint and acromion, scapula, glenoid, coracoid process, humeral head, ribs, vertebrae, pedicl es (will often see Bony structures: metastatic disease here)
o
Soft tissues
o
Lung fields and hila (see his tutorial)
tissue: calcification of carotid, LN calcification, masses, abdomen, stomach bubble, splenic f lexure, neck and chest wall Soft tissue: Right upper, middle and lower lobes; left upper and lower lobes Left
The right lung comprises 10 segments: 3 in the right upper lobe (apical, anterior and medial), 2 in the rig ht middle lobe (me dial and lateral), and 5 in the
1 fissure- oblique oblique
right lower lobe (superior, medial, anterior, lateral, and posterior). Right
The left lung comprises 8 segments: 4 in the left upper lobe (apicoposterior, anterior, superior lingula, and inferior lingul a) and 4 in the left lower lobe
2 fissures
(superior, anteromedial, lateral, and posterior). TB likes posterior segment of upper lobe Immunocompromised- superior segment of lower lobe o
Diaphragm and pleural spaces
o
Mediastinum and heart
o
Abdomen and neck
o
Pit falls
– if left higher may have loss of lung volume (e.g. atelectasis) Right hemidiaphragm is higher than the left – if
Poor inspiration Over or under penetration Rotation
Lungs o
Upper, middle, lower lung field; hilar structures including PA and PV; pulmonary vascularity, diaphragm, costophrenic sulcus; right hemidiaphragm is usually higher than left
o
Carina
(if left higher, might be phrenic nerve palsy but most commonly loss of lung lung volume such as atelectasis; tumor). Then compar e one side to the other Look for lymph nodes in this area (e.g. stage 4 lung cancer, no longer operable) Si lh lho ue ue tt tt e/ e/S ttrru ccttu rree
Upper right heart border/ascending
C on on tta ac t wi th th L un ung
Anterior segment of RUL
aorta Right heart border
RML (medial)
Upp er er le le ft ft he he ar art bo bo rd rde r
An te te riri or or se se gm gm en en t o f L UL
Left heart border
Lingula (anterior)
Aortic knob
Apical portion of LUL (posterior)
A nt nt er er io io r he he mi mi di di ap ap hr hr ag ag ms ms
(right anterior oblique = left posterior oblique) Medial segment of middle lob abuts the heart
L ow owe r lo lo be be s (a (a nt nt er er io io r) r)
Heart o
Cardiac shadow/size. Borders of heart, trachea and bifurcation, atria/ventricles
o
Right atrial enlargement Could be tricuspid regurgitation Right sided strain
Lateral view o
Square vertebrae, aorta and scapula look a bit different. Lun gs should be blacker as you go down in a lateral view.
o
On lateral, to know which diaphragm you’re looking, gastric bubble on left. Left hemidiaphragm has heart on it Silhouette sign – two tissues of similar densities that are next to each other, you won’t be able to recognize the difference
o
Vertebra should get progressively darker as you go down
Look at segments : o
right upper lobe segments – superior, anterior, posterior (posterior associated with TB); left upper lobe segments – anterior, apical posterior; right lower lobe – superior, anterior, posterior, mediolateral
Pathology / other o
Tracheal deviation: thyroid, thymus, teratoma, etc.
o
Most common cause of perforated viscous is an ulcer (duodenal or gastric). Anytime you suspect a perforation or a leak from an anastomosis etc----can ONLY use water soluble contrast!!! Other causes- diverticulitis (unusual), iatrogenic, colon (intraperitoenum – cecum, transverse, sigmoid, jejunum)
Do left side down so that air goes up to right side and see air above liver
o
Hiatal hernia – can see it hyper dense behind the heart. On lateral, see air pocket
o
May occasionally have cervical (rudimentary) ribs, air in subcutaneous tissue, absence of clavicles etc. Can use a grid to c lean up scatter.
Consolidation and atelectasis (collapsed alveoli – can be due to obstructive (plugging), compression (fluid collection), scarring) o
air bronchogram – can see bronchus clearly because alveoli are filled with something (consolidation or atelectasis, differentiate by clinical f indings) if see bronchograms, can’t be due to something plugging up bronchus An air bronchogram is a tubular outline of an airway made visible by filling of the surrounding alveoli by fluid or inflammat ory exudates. Six causes of air bronchograms are; lung consolidation, pulmonary edema, nonobstructive pulmonary atelectasis, severe interst itial disease, neoplasm, and
normal expiration. o
Any time you see loss of volume, post-obstructive pneumonias can occur MUST obtain follow-up x-ray 4-6 weeks
o
Look at level of diaphragms for evidence of loss of volume. Can also have mediastinal shifting due to loss of volume.
o
*If see heart right border, RIGHT MIDDLE LOBE normal .
o
Can see growth plates in humeral heads signifies child
o
Ex. RLL pneumonia --- can see heart border on lateral CXR (posterior border of LV)
o
Lingula blocks left horder border
o
Loss of volume = atelectasis due to endobronchial obstruction lesion (e.g. carcinoma)
Elevated left hemidiaphragm o
Loss of volume -atelectasis, PNA
o
Abdomen mass pushing it up
o
Ascites (should push up both)
o
Paralyzed left hemidiaphragm
Tension Pneumothorax ○
If ever a question of pneumothorax, order an expiratory CXR. Tension pneumo decreases venous return o
Air inside the pleura, collapses lung
See line of visceral pleura
○
Mediastinal shift
○
Bigger than you suspect
totally straight line – think hydropneumothorax(or hemopneumothorax if see bullets) o
Air fluid line- straight line
Can have bullous emphysema - can grow large enough to cause compression of the lung
COPD o
Beyond 10 ribs = obstructive disease
Mediastinal emphysema (air in mediastinum = pneumomediastinum) – can be caused by esophageal tear or tracheal rupture, iatrogenic from procedure, idiopathic o
do a water soluble contrast esophagram if suspect tear
o
medical emergency because can lead to mediastinitis
Epiglottitis – thumb sign, steeple sign
Pleural Effusion o
opacification of the left hemithorax – due to large amount of fluid, with shift of mediastinum likely due to pleural effusion meniscus line – pleural effusion fluid PA position: need 200-500mL of fluid to blunt costophrenic sulcus Lateral: 150mL to blunt costophrenic angle If suspect small amounts of fluid in pleural space can get decubitus film If suspect pleural effusion on right, get right lateral decubitus. If suspect pneumo on right, get left lateral decubitus.
Effusion is fluid in a potential space, there is no air there normally
Can have shift of mediastinum to side of opacification loss of volume (e.g. left pneumonectomy)
Masses
o
Mass (>3cm) vs nodule (<3cm)
o
Describe characteristics: density (does it contain calcium benign, inflammatory process with dystrophic calcification). Other examples: describing mass: well circumscribed, smooth and uniform shard borders or irregular spiculated borders or lob ulated borders, uniformly dense, speckl ed calcification, ring like, necrosis or cavitation (malignancies break down and run out of blood supply) When you see a nodule or a mass in the lung, check to see if they have older films A lesion that has demonstrated no ch ange over a period of two years is consid ered to be benign Ghon’s complex: calcification in hilum (likely to have calcifications in periphery as well) Granulomas calcify If not as dense, is likely tissue density instead of calcification.
o
If new, will need to biopsy. If biopsy and malignant, do CT scan to check for metastasis
o
Irregularly shaped lesion that infiltrates into surrounding tissue; air in center so know it is cavitating.
It can be a tumor or a lung abscess (fever, white count, etc). If see fissure elevated, have loss of volume. (horizontal fissure is bowed up)
When have irregular mass and loss of volume, likely tumor (pneumonias do not often give loss of volume)
Air in middle of lesion is necrosis
o
Alveolar vs. interstitial processes Alveolar processes are acute - PNA Fluffy, white, not well defined Interstitium-chronic-fibrosis
Cavities
o
Thin-walled cavity: bleb, bullae, coccidiomycoses (grape-skin cavity)
o
Thick-walled cavity (fairly well-circumscribed): granulomatous disease, histoplasmosis (ohio), blastomycosis, TB, fungal diseases
o
Thick-wall and lobulated centrally – squamous cell carcinoma
NEVER drain a lung abscess because can lead to an empyema (infection in the pleural space, which you have to drain); tx abscess with antibiotics
Mediastinum o
Ant mediastinum – retrosternal goiter, lymphoma, thymus, thyroid, lipoma, germ cell tumors (teratoma), diaphragmatic hernias (lumbocostal, hiatal) 4 T's (teratoma, thy mus, thyroid, terrible lymphoma) `Thymoma- Myasthenia Gravis (80-20) ---what percentage of people have thymoma in MG - 20%
o o
post mediastinum – neurogenic tumors (schwanomma), esophagus (diverticulum, neoplasm), diaphragmatic hernia, germ cell tumor (rare) middle mediastinum – enlarged LNs, cardiomegaly, vascular aneurysms, cyst (eg pericardial, GI, bronchial)
sarcoidosis – paratracheal adenopathy, bilateral hilar adenopathy
hilar adeopathy can also be lymphoma
multiple nodules of varying sizes – almost always metastases
Posterior segment of upper lobe (avg pt) and superior segment of lower lobe: think TB (old)
o
Vs multiple nodules on same side of chest (granulomatous disease)
o
Elevated right hemidiaphragm -loss of volume
o
When also affecting the vertebral column Pott’s disease
Aspergillosis: fungus ball in cavity
5 Categories: Congenital, trauma, infectious, neoplastic, everything else (metabolic) Other: Direct signs of collapse indicate diminished lung volume:
1) Septae will be displaced TOWARD the collapsed lung 2) The lung will be more radioopaque due to loss of air.
3) The bronchi will appear crowded together. Indirect signs of collapse:
1) Hilum/Mediastinum will be displaced TOWARD the collapsed lung. 2) Ipsilateral hemidiaphragm will be elevated. 3) Rib cage size will appear diminished. (Compare with old films!) 4) Compensatory emphysema:contralateral lung appears more radiolucent. Patterns of collapse: Lobe
Direction of collapse
Shift of fissures
RUL/LUL Superiorly, medially, anteriorly On right, minor fissure shifts upward and medially (PA) R ML
I nf er io rl y a nd me di al ly
M in or fi ss ur e s hi ft s d own wa rd (P A)
RLL/LLL Inferiorly, medially, posteriorly Major/oblique fissures shift downward and backward (LAT)
HEART
can see calcium in intima of aortic aneurysm
can see prominent ascending aorta on RSB (Marfan’s if 6’6”, syphilis rare, post-obstructive aortic dilatation, atherosclerosis)
CHF with pulmonary edema; CAD/ischemic myopathy is most common cause of pump failure
o
o
o o o
Atherosclerosis of intima
Aortic stenosis
Normally can see hilar vessels Pulm edema- see bat wing configuration Nl LVEDP - <12
Increased venous pattern in the apical segments ( cephalization) (increased in blood flow to the upper lung veins) (cephalization goes away if patient lays down?) o
Vasoconstriction around lower lobe veins shunts blood to the upper lobe veins
o
Fluid around vessels cause perivascular cuffing; mediated by oncotic and osmotic forces
o
will eventually lead to interstitial fluid leading to kerley b lines (lymphatics taking fluid away); kerley b lines are best seen in lower corners of the film , horizontal lines Patient gets Paroxysmal nocturnal dyspnea Will hear a wheeze b/c there is fluid in interstitium = CARDIAC ASTHMA LV pressure 18-20 Then see Frank pulmonary edema (pressure 24-25) - fluid everywhere including thealveoli Fluid gets dumped into pleural space --> pleural effusion (EF = percentage of blood ejected in each stroke---decreased in HF)
MR: holosystolic murmur at apex radiating toward axilla. See left ventricle and left atrial enlargement
Can get fluid in pericardial space – pericardial effusion (dx by ECHO)
o
o
Elevation of left main stem bronchus (normal angle should be about 70 degrees)
Globular heart (water bottle shaped)
o
MITRAL STENOSIS: If left ventricle is normal but left atrium is enlarged,likely Mitral Stenosis (diastolic murmur); sometimes can see left atrium on right side of heart. Also see large PA due to secondary pulmonary HTN
o
*Left atrium enlargement from mitral regurgitation and mitral stenosis o
Mitral stenosis - diastolic murmur
o
Mitral regurgitation-holosystolic murmur radiating to axilla
LV not enlarged Left ventricle is enlarged
**Left border- aortic knob, main pulmonary artery, left atrial appendage (left atrium), Left ventricle
Unable to see arch of aorta
o
Coarctation of aorta
o
Notching of the ribs
normal pacemaker should be in apex of right ventricle o
Trabeculated
o
Bipolar pacer- two leads
Central line complications: thrombosis, infection, PTX (central lines should go in distal superior vena cava justproximal to the entrance into the entrance of the right atria- 2 cm above junction of SVC and RA) - needs to be past valve in brachiocephalic o
Right atrium not a good place b/c tricuspid valve is there and can cause arrhythmia ; non infectious endocarditis
Other
-
VSD
-
ASD
o
-
RV and LA will be enlarged
o
LA is normal to small
o
RA will be enlarged
o
RV will be enlarged
PDA o
LA enlarged and LV enlarged
What Radiology tests to order and when!
ACR website has “appropriateness criteria” - clinical modules
GI o
Acute massive hemorrhage- significant bloody aspirate, hematemesis, hematchoezia or severe melana
o
Upper GI bleeding - s1. stabilize, 2. endoscopy Ulcers, varices are most common causes Endoscopy - to find ulcer and sclerose it or varix
o
Lower GI bleeding MCC- diverticulosis (also AVM) Technetium labeled Radionucleotide RBC scans
LLQ -left hemicolectomy
Colonoscopy vs barium enema Enteroclysis for small bowel studies (usually do to polyps---tube down inject bar ium to see where it goes) o
Angiography Diagnostic: AV malformations, angiodysplasia Treatment
Chronic blood loss o
Fe def anemia or positive stools for blood Air contrast barium enema
Role of colonoscopy
Air contrast GI series Small bowel study Angiography
Diverticulitis o
Symptoms: LLQ pain, fever, occasional diarrhea
o
CT abdomen AND pelvis – with and without contrast (delay imaging two hours after contrast) With oral contrast and IV contrast
Gallbladder disease o
U/S, HIDA scan HIDA shows you if cystic duct is open or closed; drug tagged with radioactive
Body treats substance like bile -- -if it goes into gallbladder you know the cystic du ct is patent and does not have acute cholecystitis
o
Gall bladder wall thickening- 3mm or more is indicative of gall bladder wall inflammation
o
US- look for stones, wall thickening, cholecystic fluid
Urinary Tract o
NON CONTRAST CT bc stone is white on x ray and contrast is same color
o
Calculi: helical CT most accurate
o
Obstructive uropathy: U/S will tell you size, configuration of kidn eys, and if obstruction exists Could do plain xray to see if you can see the stone If small and can't see it it will pass by itself
Postmenopausal bleeding o
History – question hormone use
o
U/S – transabdominal if question transvaginal
o
If questions remain, MR
Adnexal masses o
U/S – transabdominal and/or transvaginal
o
MR imaging
Ectopic pregnancy (hormone levels, U/S with color Do ppler imaging)
Chest lesions o
Solitary pulmonary nodule
o
CT
o
PET scanning (benign vs malignant); nodule has to be 2cm in size to be seen
o
Pulmonary Embolus
CXR (previous films, age, hx, nodule size and configuration)
Positive nodule must be biopsied b/c high probability of malignancy CXR (other causes), V/Q scan, spiral CT, ang iography, role of MRA
suspect PE, before CTA do a plain film xray to rule out other causes
do v/q scan for pregnant patients, contrast allergy (half the amount of radiation in CTA)
Ventilation - breathe in radioactive xenon- perfusion- give tagged albumin to see if there is an area that doesn't perfuse
Acute stroke o
NON CONTRAST MRI
o
Most strokes are embolic --- obstruction to blood vessel
o
MR after 24 hours
o
Angiography Most often for therapy
Catheter into common carotid and inject tPa-helps prevent GI bleeding
Encephalitis o
Differentiate b/w hemorrhage, abscess, tumor
o
MR imaging
o
If unavailable in area then CT with contr ast
Sinusitis o
Coronal CT (non contrast)
o
First 30 days you don't image
o
Imaging to see where blockage is so surgeon can go in
Low back pain
o
If not better after 30 days- MR imaging
o
MR imaging, CT, plain films only if trauma, lumbar discography
o
Fever (osteo), malignancy (mets), and trauma (compression fx) are red flags
Child Abuse o
Skeletal survey To include skull, chest, lumbar spine, and extremities (single large x-ray inadequatE) Multiple fractures at different stages of healing Most common are stripping of the per iosteum and avulsions at growth plates (small avulsion fractures at m etaphyses of bones) View with suspicion- fracture in an ambulatory child; metaphyseal avulsion fractures
LAO- right heart becomes more prominent
FLUID GIVES MENISCUS
ICU Lecture
reading ICU CXR o
check it is an adequate film
o
check for tubes, lines, catheters 30% placed incorrectly
ICD-thick wire portion
HEART VALVES
Tricuspid and mitral valve below line Aortic and pulmonic above
struts of prosthetic valves go in direction of flow
endotracheal tube o
End should be 4cm above the carina
o
complication of trach tubes – stricture, most common is aspiration pneumonia, atelectasis if placed too f ar and ends up in RMSB
o
cuff can press against trachea and can compress bloo d supply (to prevent this, drop cuff every hour); when drop it, secretion s accumulate above the cuff (can lead to aspiration
Flexing head moves NG tube downward, could enter RMSB
pneumonia) o
halfway between chorine and thoracic inlet
o
A portable chest x-ray and close-up of a properly placed endotracheal tube (arrows) and location of carina (^).
Chest tubes o
Removing air or fluid
o
PTX-up higher b/c air up higher
o
Fluid-lower
Central Line o
The intravascular volume status of critically ill patients is crucial to their management. A CVP can be obtained directly via central vein catheters placed either through the subclavian veins or the internal jugular veins. Similarly, intravenous catheters may be used to infuse large volumes over lon ger periods of times with little chance of thrombosis.
o
Ideally the catheter tip should lie between the most proximal venous valves of the subclavian or jugular veins and the right atrium.
o
How far from the brachiocephalic vein are these valves? o
Approximately 2.5 cm from where they join to form the brachiocephalic vein. Usually the last valve in the subclavian vein is at the level of the anterior portion of the first rib.
o
Dophoff tube o
thin tube used for feeding with radiopaque end (metal tip)
o
Smaller
Swan ganz catheter o
should be in either right of left pulmonary artery at the edge of the cardiac shadow
o
Can be inserted in femoral, subclavian or jugular
o
Triple lumen
o o
2 complications: thrombosis of vessel or hemorrhage Need to decompress balloon after you wedge the catheter, otherwise will occlude blood flow and create a wedge -shaped infarct
o
After open heart surgery, want to put in mediastinal drains (otherwise accumulation of blood can cause tamponade) o
Underneath heart on pleural surface
Film -
-
Cannot see through the left heart to the pulmonary vessels Large white thing behind heart- not pleural fluid b/c can see costophrenic sulcus - could be consolidation or atelectasis of left lower lobe PNA vs. atelectasis - clinical difference
ARDS – o
damage to type II pneumocytes and endothelium of alveoli, fluid leaks across cell membrane PAS positive membrane can’t oxygenate
o
Sepsis, hypoxia, trauma, shock, hypovolemia
o
Patchy alveolar infiltrates
o
alveolar disease – looks like patchy clouds in the lung
interstitial disease – looks like linear pattern
Atelectasis o
fissures will be moved over
o
do not confuse with fluid
o
often due to mucus plugging
o
Radiographic Appearance of Atelectasis Radiographically, atelectasis may vary from complete lung collapse to relatively normal-appearing lungs.
For example, acute mucus plugging may cause only a slight diffuse reduction in lobar or lung volume without visible opacity. Nevertheless, the physiologic effects can be significant. In the so called mucus plugging syndrome, the association o f sudden hypoxia with a normal or quasi-normal chest radiograph can lead to the suspicion of a pulmonary embolus. Mild atelectasis usually takes the form of minimal basilar shadowing or linear streaks (subsegmental or "discoid" atelectasis) and may not be physiologically significant.
Atelectasis may also appear similar to pulmonary consolidation (dense opacification of all or a portion of a lung due to filling of air spaces by abnormal material),
making it difficult to distinguish from pneumonia or other causes of consolidation. The distinction between atelectasis and other causes of consolidation is important, and certain clues exist to aid in making that determinatio n. Atelectasis will often respond to increased ventilation, while pneumonia, for example, will not. Crowding of vessels, shifting of structures such as interlobar fissures towards areas of lung volume loss and elevation of the hemidiaphragm suggests atelectasis. Another key for distinguishing b/w atelectasis and consolidation is recognition of the typical patterns that each pulmonary lobe follows whencollapsing.
Right upper lobe atelectasis is easily detected as the lobe migrates superomedially toward the apex and mediastinum. The minor fissure elevates The left lung lacks a middle lobe and therefore a minor fissure, so left upper and the inferior border of the collapsed lobe is a well demarcated curvilinear lobe atelectasis presents a different picture from that of the right upper lobe border arcing from the hilum towards the apex with inferior concavity. Due
collapse. The result is predominantly anterior shift of the upper lobe in left
to reactive hyperaeration of the lower lobe, the lower lobe artery will often
upper lobe collapse, with loss of the left upper cardiac border. The expanded
be displaced superiorly on a frontal view.
lower lobe will migrate to a location both superior and posterior to the upper lobe in order to occupy the vacated space. As the lower lobe expands, the lower lobe artery shifts superiorly. The left mainstem bronchus also rotates to a nearly horizontal position. LEFT UPPER LOBE- blur left of heart border
Right middle lobe atelectasis is difficult to detect in the AP film (left). The lateral (right), though, shows a marked decrease in the distance between the horizontal and oblique fissures. Right middle lobe atelectasis may cause minimal changes on the frontal chest film. A loss of definition of the right heart border is the key finding. Right middle lobe collapse is usually more easily seen in the lateral view. The horizontal and lower portion of the major fissures start to approximate with increasing opacity leading to a wedge of opacity pointing to the hilum. Like other cases of atelectasis, this collapse may by confused with right middle lobe pneumonia.
Pneumothorax o
deep sulcus sign: will see costophrenic angle go very deep
o
barotrauma – trauma induced by the pressure of mechanical ventilation
o
want to have CT near apex
o
In the supine patient, intrapleural air rises anteriorly and medially, often making the diagnosis of pneumothorax difficult.
o
ORDER LLD left side down for Right pneumothorax
Tension Pneumothorax
o
Tracheostomy tube o
Balloon at end of tube - should be same width as trachea (not larger)
o
Can lead to stricture
NG tube o
has end hole and side hole (in case end hole gets blocked)
o
for feeding – put post or close to pylorus
o
for decompression – past LES is fine
Intra-aortic balloon pump o
want marker to be just distal to the subclavian
o
bilateral patchy lower lobe infiltrates – almost always aspiration pneumonia especially in ICU
o
o
nice air bronchograms = pneumonia, not atelectasis
hemoptysis: TB, bronchitis/bronchiectasis, bronchial carcinoma, fungal infection
Mediastinal Emphysema
o
Balloon tracheostomy dropped down
o
Pneumopericardium
o
o
A. Portable upright chest x- ray before aspiration; B. Chest x-ray 1 hour after aspiration, showing bilateral diffuse alveolar infiltrates, worse at the bases on the right side
Heart Failure
Other
o
o
ET tube - Children halfway b/w carina and and thoracic inlet
o
AORTA-POSTERIOR SEGMENT
Abdomen
abdominal upright film o
rotation: look at vertebrae and ribs.
o
Supine film Should see bottom of pubis
Should see diaphragms
o
Gas patterns o
look for small or large bowel obstruction which would lead to ischemia to necrosis to perforation
o
do both supine and erect films when looking for obstruction
o o o
if pt can’t stand, do AP and left lateral decubitus plicae of small bowel go all the wall across haustra of large bowel go part o f the wall across the wall normal colon can be 5-6 cm in size. Cecum about 10cm ascending and descending are retroperitoneal
transverse and sigmoid are intraperitoneal
Obstruction o
Determine large vs small
o
Mechanical vs ileus Mechanical air fluid levels at different heights means that there is tone present (so you can be certain this is a mechanical obstruction as opposed to ileus)
Paralytic Ileus
o
Large Bowel Osbruction o
May get dilated small bowel b/c of incompetent ileo-cecal valve
o
Sigmoid Volvulus Sigmoid Volvulus with a markedly distended loop of colon in the midlin e of the abdomen. There is a thin vertical band of tissue pointing toward the left upper
quadrant. This tissue band represents the medial walls of the twisted colon and is present in 60-70% of patients. The colon converges toward the pelvis. There is no air in the rectum due to the obstruction.
o
o
LBO- Sigmoid Carcinoma
Large spleen o
ITP, lymphoma, spherocytosis, CLL
o
Pushes colon medially
If enlarged kidney o
push descending colon lateral
most common visceral structures that rupture: gastric/duodenal ulcer
Pyloric ulcer-- can obstruct stomach --- get enlarged stomach
Case - PANCREATIC PSEUDOCYST
o
Delayed empyting - gastroparesis - in diabetic
o
n/v/ abdominal pain
o
Soft tissue mass - 8 cm rounded mass with good sharp borders in LUQ
o
LUQ- It could be the pancreas, spleen , kidney, adrenal, stomach, or abdominal wall.
o
Case - pancreatic pseudocyst o
Mass- calcified 6-7 cm rounded mass LUQ
o
? Kidney cyst - do oblique and see if it moves with kidney -- could do US
o
Aneurysm - Splenic artery aneurysm (females)
Case - Gallstones + pseudocysts in ducts = Gallstone Pancreatitis o
Abdominal pain/ nausea/ vomiting
o
Calcifications in RUQ
Gallstones (20% calficified) Other calcifications look like in the ducts - pnacreatic duct calcifications o
Something pressing on stomach
Large soft tissue density Also calcifications on the right side o
Erect film
Can see air fluid levels Calcifications fell down inside something = Gallstones
Case = Appendicitis o
RLQ pain + calcifications
o
Pathophys- obstruction at neck of appendix
o
Abdominal pain, N/V
o
Calcifications
o
Pneumotosis Intestinalis- Intramural Air o o o
air in the wall of the bowel, caused by ischemia due to obstruction will see both luminal and serosal side of bowel NICU babies - necrotizing enterocolitis - air in wall of bowel
o
Necrotizing enterocolitiswith perforation of the terminal ileum.
Free Air o
Pneumoperitoneum
Can see retroperitoneal free air around kindney
Kidney above liver -
Uterine Fibroids
Soft Tissue Abscess
o
o
ERCP, trauma
uterine fibroids will calcify
o
Abscess - Lesser sac abscess secondary to pancreatitis
o
The presence of gas and fluid in the lesser sac is usually from a pancreatic abscess, but other or gans must be considered suc h as the duodenum, stomach, or an enteric fistula.
o
Abscess in uterus- endometritis
air forming abscess looks like cloudy/puffy structure
Volvulus o
Sigmoid (intraperitoneal)
o
o
Cecum can also volvulate
when looking for free air – left lateral decub
Ultrasound
best to do ultrasound over fluid filled area (not lung or bone)
we use the terms hypoechogenicty (black ), hyperechogenic (white); isoechoic - muscle -- normal
Anechoic - fluid filled - gallbladder - no echo
TIA - check for carotid doppler
Cannot be used for bowel
Uses o
Liver Mass lesions Portal vein flow
o
Gallbladder
o
Kidney
o
Aorta
o
Misc
Obstruction/hydronephrosis
Fluid in abdomen
Hepatic vein to IVC Decrease flow by 50%--- need to have lumen narrowed by 70% blood vessels/fluid will be black
cant see bowel well
can see hepatic vein thrombosis (budd chiari)
Benign cyst – anechogenic, smooth borders, increased through transmission - increased echoes
mass in the breast, thyroid and scrotum are good for distinguishing between solid and cystic lesion
Advantage b/c real time so yo u can have patient sit up to dif ferentiate GB stone vs polyp
GI
video fluoro studies for swallowing problems
double contrast GI is done when you are looking for abnormalities in mucosa
when small bowel gets inflamed, it gets spikey like picket fence
dysphagia:
o
tumor, diverticulum, schatzkis ring, stricture, achalasia, eosinophilic esophagitis, ulcers
o
Do swallowing function video study
Esophagus o
Barium swallow or esophagram - study of esophagus
o
Done with single or double contrast Double contrast- high density barium (sour cream consistency)-coats muco sa so better view of mucosa
If patient is cooperative the standard test is DOUBLE CONTRAST GI study
For patient who cannot turn, follow orders, etc- SINGLE CONTRAST GI study o
Don't visualize mucosa as well
Diverticula
o
Zenkers Diverticulum
o
Esophageal Varices
o
Esophagitis
o
Duodenal ulcer
o
o
Contrast goes into hole in mucosa)
Esophageal Tumor
o
Adenocarcinoma of the Stomach
Polyps
o
Esophagus - 12 mm or less - need to operate o
Barium pill that is exactly 12 mm in diameter
o
Esophagram with Barium pill Study
Diaphragmatic Hernia
o
Malignancy
Overhanging shelf (stricture tapers)
Barretts Esophagus
o
o
Barrett esophagus with a midesophageal stricture and a reticular pattern. Do uble -contrast esophagogram shows a focal area of mild narrowing in the midesophagus (black arrow). Note also the distinctive reticular pattern that extends distally a considerable distance from the stricture (approxi mately to the level indicated by the white arrow). This reticular pattern is thought to result from intestinal metaplasia in Barrett mucosa.
Contrast
thickening of colon wall and blood in submucosa – ischemic colitis
o
o
Barium for esophagus on down
shaggy exudative yellow crap – C. diff
Ulcerative Colitis o
Lead pipe appearnce
o
Multiple small lesions in colon with no haustra and lead pipe appearance – ulcerative colitis o
UC generally starts in left colon (rectum) and Crohn’s in the right colon (terminal ileum)
o
UC has tiny shallow ulcers and Crohn’s has large deep ulcers that penetrates
o
UC rarely has fistulas whereas Crohn’s often has fistulas
o
UC is continuous and Crohn’s has skip lesions
o
UC has high rate of malignancy and Crohn’s has lower Crohn’s have abnormalities of sacroiliac joints and in biliary tree; can manifest anywhere in GI tract UC is limited to the colon
o
Both happen in the young but Crohn’s is bimodal and can present later in life as well
Crohns Disease o
String sign
Enterocolic Fistula
Men can get fistula between colon and bladder and get air in the urine. Women do not because uterus in between.
When see narrowing or structuring in UC, think cancer
Reserve CT for complication search (fistula, abscesses, etc)
Barium study is study of choice f or Crohns and colonscopy for UC
Can see apple core lesions – carcinoma of the colon
HIDA
Normal filling o
give patient IV drug tagged with tecnichium which is excreted like bile (get outline of liver); if see bile ducts, means the y must be dilated
o
Dilated common bile duct and dilated pancreatic duct ampulla of Vater obstruction
o
Double Duct sign Dilated pancreatic and common bile duct
Liver o
Metastatic disease
CT
Splenic vein runs on dorsal aspect of spleen (lesions of the pancreas like carcinoma or pseudocyst can obstruct the splenic vein and can lead to varices)
http://fitsweb.uchc.edu/ctanatomy/abdomen/axial.html
same densities but now we can distinguish between water and soft tissue
can see enhancing (with blood supply, lighter ) with darker fluid in middle – likely a pseudocyst
contrast o
barium – inert
o
gastrographin is water soluble oral contrast
o
iodine tagged to inulin (for kidney) or other substances
o
ionic – dissociate into component molecules (increased side effects)
o
non-ionic – bound to an organic compound; less side effects
o
Gadoliniumfor MR Contrast Need to know GFR If GFR less than 30 it is CONTRAINDICATED to give pat ient contrast during MRI May develop diffuse systemic sclerosis 30-60 need very good reason to give contrast -life o r death situation GFR > 60 to be safe
o
Stop metformin 12-24 hours before giving contrast and at least 24 hrs after giving contrast
IV contrast uses: anatomic clarification, assess perfusion, angiography, lesion characterization, assess defects in BBB, assess for extravasation
Tumor enhances b/c it has blood vessels; a cyst won't
to do IV contrast CT pt cannot have Cr over 2, between 1.5-2 better have a good reason for CT
o
o
MUST CHECK PATIENT’S CREATININE
e.g. cecum enhancing - most likely a tumor
best way to prevent AKI is hydration
patient must be off metformin for at least 12 hours prior to CT and keep pt off for 48h after or patients will often go into lactic acidosis
gadolinium is the contrast used in MR must be tagged to organic substance, m ust check renal fx o o
if GFR is under 30ml/h it is contraindicated to give contrast between 30-60ml/h should be a good reason
non contrast CT – looking for head bleed and looking for stones
ER/MSK
to clear C-spine: cross table lateral through collar,----then can do other views A/P, adontoid
Abdominal/Pelvic
o
AAA – CT/US
o
renal colic – non contrast CT/US/IVP
o
cholecystitis – US/HIDA
o
appendicitis – CT/US/plain film
o
ectopic – US
o
testicular torsion – US/nuclear
o
trauma – CT/US
SKELETAL RADIOLOGY o
ankle: A/P, lateral, oblique’
o
hip: A/O, frog leg, lateral
o
Shoulder
Colles Fracture
o
soft tissue swelling is often an indication for the location of a fracture
o
Fracture Base of 5th Metatarsal
o
Fracture Descriptions Number of fracture framents (simple or comminuted (more than 1)) Direction of fracture line (transverse right across bone, oblique diagonally, or spiral)
Transverse: force applied perpendicular to long axis of bone; fracture occurs at side of force
Relationship of one fragment to another (displacement, angulation, shortening, and rotation – determines whether will splint or need OR) Open to atmosphere (outside) – closed or open (compound) o
if you think kid has fracture, splint for 7-10d and then re-xray
o
Hip fractures
Subcapital (base of head) Most common
Femoral neck
If fracture subcapital or higher part of neck, will damage middle circumflex and can develop avascular necrosis
Easier to fix
If this is the case, they can go in and replace it right away
Intratrochanteric Good blood supply still, so go in and nail it
o
Green stick/buckle fracture in children – bendable bones In children, get a film in the view that you see the abnormality, but look at other side for comparison
o
increased bone density think avascular necrosis (femoral head and scaphoid)
o
Abnormal fat pad Most likely an occult fracture
o
Dislocations
o
Rotator Cuff tear
o
Scapho Lunate
o
Hand Bones
o
Lunate dislocation
Anterior vs. posterior
o
Children
Look for epiphysis plate fractures Will cause growth problems
o
Mallet Finger
Space should not be more than 3 mm don’t miss a c2 fracture of dens
Can happen in RA o
ACL tear
o
liss-frank fracture – increased space between first and second metatarsal
o
cortical thickening Paget’s; marketedly elevated alkaline phosphatase (indicates marked anabolic overgrowth in bone)
Frontal radiograph of the pelvis shows marked sclerosis of the sacroiliac joints, as well as the iliac bones, left greater than right (correlating with the bone scan findings). Additionally, there is severe osteoarthrosis of the hip joints, with joint space narrowing and remodeling of the femoral heads. o
Sickle cell: 17yo with enlarged heart due to anemia and high output failure, dense white bone due to sickling Dense ribs Cortical infarcts
o
Arthritis degenerative arthritis – most common bone abnormality (osteophytes, narrowed joint spaces, sclerosis) □
involves DIP joints (in contrast to rheumatoid, which involves PIP)
rheumatoid – erosions in early rheumatoid subchondral increased lucency/destruction and sclerosis characteristic of aseptic necrosis Scleroderma
□
o
Metastatic disease / pathologic fracture
o
Increased bone density =
Osteoblastic metastases or avascular necrosis (dead bone) o
Neurofibroma
o
Bone tumors irregularity with stuff growing out into soft tissues – osteosarcoma bone is irregular and periosteum is elevated; one area growing into soft tissue – osteoid tumor living in epiphysis – osteoblastoma in middle phalanx along medial aspect, can see sub periosteal resorption associated with hyperparathyroidism
benign tumor expands bone but has a sclerotic rim (body walls it off) □
Well defined edges
o
Deposition Arthritis of abnormal substance in joint Gout – inability to metabolize purines, so uric acid is deposited in soft tissues, classically in synovium; classically in first pha lanx
o
thin periosteum in fingers (lacy-like) – osteoporosis(not enough mineral in bone)
o
thickening of bone can be osteoblastic metastases (eg prostate)
o
SCFE draw line perpendicular to middle; if femoral head extends outside of line, SCFE can lead to avascular necrosis
Normal - head comes over neck
Klein lines are drawn along the superior cortex of the femoral neck. A normal Klein line will intersect the epiphysis. An abnormal Klein line does not intersect the epiphysis, as the femoral neck has moved proximally and anteriorly relative to the epiphysis o
Scapula Fracture
IR
INTRAARTERIAL AND INTRAVENOUS CONTRAST o
Angiograms (arteriograms and venograms) are obtained by injection of radioopaque contrast material directly into a blood vess el via a needle or catheter. The contrast is comprised of high density iodine, which attenuates the x-ray beam and makes the lumen of the blood vessel visible. The iodine is subsequently filtered through the kidneys and excrete d in the urine.
o
The fluoroscopic images are displayed digitally, and can be manipulated such that the vessel lumen appears white or black. Th e image on the right is "subtracted" which means that the bones and other structures have been subtracted from the image so that only the blood vessels are seen.
o
The forward movement of the contrast bolus that occurs concurrent with venous return (venogram) or arterial pulsation (arteri ogram) is observed fluoroscopically. Without the injected x-ray dye, the blood vessels would not be visible.
Intra-arterial infusion therapy o
Hemorrhage control
o
Thrombolysis
o
Chemotherapy infusion
o
Relief of vascular spasm
Vessel Occlusion o
Clot from somewhere else- Heart-Afib
o
Atherosclerosis -vessel thrombosis
Occlusion Therapy o
Hemorrhage
o
AV malformations and fistulas
o
Tumors
o
Organ ablation
o
Varicoceles - more common on L than right
o
IVC filters
Percutaneous Trnasluminal angioplasty o
Peripheral vascular system
o
Renal arteries
o
Distal aorta
o
Visceral arteries
Need 70% narrowing to reduce blood flow by 50%
Need to decrease flow by 70% to feel symptoms
Thoracentesis o
Stay at top of rib b/c underneath rib is artery, nerve, vein
o
Could create a fistula
check GFR before giving gadolinium
most common cause of IVC filter is recurrent DVT/PE that fails medical management
IVC Filter o
must be distal to renal vein; don’t want clot to propogate back into kidney
o
Once open it additional clots can occur so don't want to clot renal veins
Fibromuscular Hyperplasia
Subclavian steal syndrome
o
o
String of beads sign
retrograde flow in vertebral artery; due to a proximal stenosis (narrowing) and/or occlusion of the subclavian artery. The arm may be supplied by blood flowing in a retrograde direction down the vertebral artery at the expense of th e vertebrobasilar circulation.
o
o
Contrast-enhanced magnetic resonance angiogram showing the aortic arch (AA) and the arch vessels in a right anterior oblique projectio n. The proximal segment of the left subclavian artery (LSA) does not enhance and is occluded. The arrowhead indicates the site of origin of the LSA. BCA indicate s brachiocephalic artery;
Ileocolic is the last branch of SMA- goes to ileo-cecum w
Celiac artery branches
•
The x-ray dye is injected through a catheter which is located in the aortic arch. Any evaluation of the upper extremity arteries must include an evaluation of the aortic arch and the brachiocephalic trunk.
•
The aortic arch can be seen, with its three branches: the brachiocephalic trunk, the left common carotid and the left subclavian arteries.
•
The brachiocephalic trunk divides into the right common carotid and the right subclavian arteries.
•
The subclavian artery give off several branches, including the vertebral arteries. The subclavian artery becomes the axillary artery at the lateral border of the first rib.
http://www.dartmouth.edu/~anatomy/Head-neck/vessels/angiograms/CTAarch.htm Nuclear Medicine
don’t need to worry about harming liver or kidneys because loading dose is so sm all can pick up stress fractures
Checking for further lesions -osteo sarcoma--- may change plans for chemo/radiation/ surgical candidacy
Bony metastasis - seen in prostate cancer, breast cancer
To look for edema in bone marrow - MRI - but cannot do a whole body MRI study
Galium 67 citrate- spine infection, interstitial nephritis
Indium labeled WBC- soft tissue infections- thoracic pelvic region
Technetium labeled- good for extremities
Neuroimaging
Gray white junction helpful to tell health of brain
Brain MIRI
o
o
T1
o
T2
o
T1 Gadolinium
o
Flair
o
Central sulcus sign
Very good for looking at anatomy
Compare cortex to ventricle?
Vasogenic edema o
Neoplasm (GBM or met)
o
Cerebral abscess
o
Hematoma
Omega: site where hand is on homunculus o
In front: frontal
o
Behind: parietal
o
Central sulcus is the first one that interrupts and goes deepest
Anterior commissure o
Holes below = around CSF/vessels
o
Holes above = infarct
Most commonly injured nerve in head trauma is CN1 (olfactory)
Syrinx causes
o
Trauma
o
Congenital (eg Chiari malformation)
How to approach CT of the head o
Is there geometric distortion? Is something the wrong size, shape, or position?
o
Soft tissue abnormality?
o
Abnormal enhancement?
Subdural hematoma (goes along skull); if not white, means old
Cerebral Amyloid Angiopathy
o
Midline shift
o
o
Sensitivity of GRE imaging for hemosiderin in an 80 -year-old man with dementia that has progressed over the past 4 years. (a) Axial GRE MR image shows multiple fo ci of signal loss in cortical-subcortical locations. In a patient with a diagnosis of probable CAA, these foci are consistent with chronic microhemorrhages .
Ventirculomegaly o
Hydrocephalus (obstruction)
o
Volume loss (atrophy, surgical)
o
Congenital (never developed)
o
If both lateral and third ventricle are enlarged, obstruction is in aqueduct of Sylvius aqueduct stenosis (post inflammatory?)
Magnetic resonance image obtained in a patient treated with ETV for hydrocephalus due to aqueductal stenosis, revealing an open sylvian aqueduct (arrow).
Noncontrast axial head CT (A) and GRE (B) demonstrating microhemorrhages and lob ar hemorrhage consistent with cerebral amyloid angiopathy. o
Meningiomas are isointense to brain parenchyma (so need contrast to see)
o
Meningitis
o
MCA > PCA > ACA/PICA
Leptominigiomia enhancement
Glioblastoma Multiforme
o
Medulloblastoma
o
Vestibular Schwanoma
Chronic ischemic changes o
Gliosis (proliferation of glial cells), encephalomalacia (hole in brain)
o
Loss of parenchymal volume
Scalp Lymphoma
Prolactionoma
o
Pinealoma
o
Ischemic change o
Ischemic small vessel disease
o
Hypertensive vasculopathy
o
Branch vessel infarcts (MCA)
MCA infarct DWI takes 30 minutes to show up
o
Embolic infarcts (often cardiac)
Often out in periphery Subcortical white matter and adjacent cortex
o
Border zone infarcts (b/w MCA and ACA) / Watershed
Intracranial hemorrhage
o
o
Intra-axial or extra-axial? Look for relationship to the cortex/skull Widening of extra-axial space = extra axial
o
Extra-axial Epidural, subdural, subarachnoid Shape of collection? --- e.g. crescent Smooth interface with brain (does it fill sulci)? Does it respect (aka not cross) the sutures? Epidural Hematoma □
Biconvex; most are middle meningeal; a/w with fracture
Subdural Hematoma □
Usually due to tearing of veins; no consistent a/w fractures
□
Common in infants and elderly
□
Crescent shape along surface of brain; crosses suture lines
□
Acute is bright white
□
Iso to CSF = chronic
Smooth interface with the brain
Chronic SDH becomes low density as the hemorrhage is further reabsorbed. It is usually uniformly low density but may be locul ated. Rebleeding often occurs and causes mixed density and fluid levels.
□
Subacute
Subacute SDH may be difficult to visualize by CT because as the hemorrhage is reabsorbed it becomes isodense to normal gray m atter. A subacute SDH should be suspected when you identify shift of midline structures without an obvious mass. Giving contrast may help in diffic ult cases because the interface between the hematoma and the adjacent brain usually becomes more obvious due to enhancement of the dura and adjacen t vascular structures. Some of the notable characteristics of subacute SDH are: ◊ - Compressed lateral ventricle, Effaced sulci, White matter "buckling", Thick cortical "mantle"
□
Subarachnoid hemorrhage Most commonly from trauma; also ruptured aneurysm
Blood in subarachnoid space, cisterns, and ventricles
High density blood (arrowheads) fills the sulci over the right cerebral convexity in this subarachnoid hemorrhage. o
Intra-axial (ICH) Intra axial is a term that denotes lesions that are within the brain parenchyma, in contrast to extra axial, which describes lesions outside the brain, and intra
ventricular, which denotes lesions within the ventricular system. Is there associated trauma?
Contusion vs. diffuse axonal injury
If there is no known trauma:
Lobar hematoma or hypertensive hemorrhage (deep)
TRAUMA
1. Contusion
Half of intra-axial post traumatic lesions
Typically punctate or linear hemorrhages along gyri
Characteristic locations- 1/2 temporal lobes, 1/3 frontal lobes
2. Diffuse Axonal Injuries
Seen with sudden accel/decel
Often at gray white junction
Typically lose conscoiusness at moment of injury
Hard to see on CT scan
NON TRAUMA
1. Lobar Hematoma a) Into extraaxial CSF space
Supratentorial hemorrhages
In patients over 55 most likely due to Cerebral amyloid angiopathy
Consider arterial vascular malformation, tumor and cavernous malformations in younger patients
Cavernous angioma-po pcorn lesion
◊
AVM
Arteriovenous malformation (AVM) of the brain. A CT scan of the posterior fossa demonstrating a hemorrhage in the fourth ventricle, with extension to the left cerebellum.
2. Hypertensive hemorrhage
Deep intracerebral hemorrhage ◊ Basal ganglia 60-65 ◊ Thalamus 15-25 ◊ Pons and Cerebellum
MRI
Non-ionizing radiation and non-invasive; low side effects
T1: water is black,bone is white o
More like anatomy
o
When do head CT, use T1
o
Vessels look black because of the flow
o
All post contrast sequences are T1
T2: water is white, bone is black
Greatest advantage is better contrast resolution than CT, esp for soft tissue
Check GFR (>60, don’t worry about it; 30-60 need a REALLY good reason)
Unit of magnetism = tessla
Three sequences that highlight the brain are T1, T2 and flair
Shoulder MRI
o
o
Very good for detecting abnormality; sensitive but not specific
To avoid diffuse systemic sclerosis
o
Knee o
If see fibular head you know it is lateral
Avascular Necrosis
o
Psoas
Tuboovarian Abscess
o
o
Inserts on lesser tronchanter
