GI/ Abdomen and CNS/Head Radiology Flashcards
epidural hematomas are typically caused by what mechanism?
- blunt trauma (ie. MVA)
- Almost always (more than 90%) have an associated skull fracture
etiologies of dementia
- Vascular disease (e.g., multiple-infarct dementia)
- Alzheimer’s dementia
- Parkinson’s disease
- Normal pressure hydrocephalus (NPH)
- HIV encephalopathy
- Frontal lobe space occupying lesion (e.g., neoplasm, subdural hematoma)
*Brain MRI can be useful in diagnosing treatable conditions
what can free air in the abdomen be?
alway abnormal
- perforation, postop/postprocedureal
- pneumoperitoneum
what are the indications for an Upper GI fluoroscopy study? and what pathology can it detect?
Indication: epigastric pain, hematemesis, N/V, guiac positive stools, child with bilious emesis (malrotation)
Pathology: neoplasm, gastritis/duodenitis, gastric or duodenal ulcers, diverticulae, benign tumors, malrotation/volvulus
what is the test of choice for abdominal pain
Abdominal CT
*unless Gallbladder disease is suspected
what is a subdural hematoma
- hemorrhage into potential space btwn arachnoid and dura mater
- presentation w/in 48 hrs (HA, confusion, progressive dysfxn)
- high mortality rate
- tearing of the bridging veins between dural sinus and brain
what imaging would you order if someone presents with:
-Multiple sclerosis
MRI w/ Gad
Subdural Hematoma CT findings
- Acute: High-density (i.e. lighter on CT image), CRESCENT-SHAPED mass
- Subacute: “Isodense” (same density as brain)
- Chronic: Low-density (darker on CT than brain)
- possible midline shift
- distortion of Lateral ventricle
what is mass effect?
is the bowel displaced by a mass or enlarged solid organ?
what are 9 indications for abdominal U/s?
- Biliary Disease (Most common: Acute cholecystitis): Preferred modality
- Trauma Screening
- Solid Organ Lesion
- Evaluation (Cyst vs Solid)
- Appendicitis in children and pregnant women
- Vascular flow evaluation (Doppler)
- Abdominal aortic aneurysm
- Guided biopsy, ascites tap
- Pregnancy and disorders of female pelvis
what are types of nuclear medicine scans of the abdomen and what do they evaluate for?
HIDA – cholecystitis, biliary atresia, other suspected biliary disease
Tagged RBC scan – source of GI bleed
Sulfur colloid scan – evaluate liver, spleen
what imaging could you obtain for Vertigo?
- No imaging: most cases of vertigo
- Noncontrast brain CT: consider if there is CONDUCTIVE hearing loss and vertigo, not responsive to treatment
- Brain MRI: if there is SENSORINEURAL hearing loss, suspected acoustic neuroma or posterior fossa lesion
what are your imaging options for a seizure
MRI for the following:
- Healthy with new onset
- Alcoholic with new onset
- Epilepsy with poor therapeutic response
- Focal neurologic deficit
- Abnormal EEG
- non-contrasted CT used w/ trauma
what are the 3 main types of intracranial hemorrhages
- Epidural hematoma
- Subdural hematoma
- Subarachnoid hemorrhage
what bones can you see on an abdominal plain film? and what do you assess for?
- spine
- pelvis
- ribs
- prox. femora, hips
-fxs, bony erosions, degenerative changes
how do you assess calcifications on an abdomen plain film
- location
- shape:
- Round lucent center = phlebolith (calcified venous thrombi)
- Branching (staghorn) = renal
- Round and in RLQ…think appendicolith
what is a bulge in disc disease?
- diffuse enlargement of disc area
- Very common
*Usually not clinically important
May contribute to spinal stenosis
what is a benefit of an ERCP study?
treatment can be performed simultaneously:
- sphincterotomy
- stent placement
- dilation of strictures
- stone removal
what imaging is most sensitive in detecting early ischemic stroke?
MRI (more so than CT)
what organs can you see on an abdomen plain film?
- liver- location can often be estimated by location of ascending colon (difficult to assess heptomegaly)
- spleen- hard to visualize
- bladder- hard to visualize
- kidneys- Perirenal fat usually outlines kidneys, making them visible on plain film. (Appear to sit atop psoas muscles)
site of dilated loops in LUQ can possible be caused by:
pancreatitis
why is a waters’ view angle used for plain film?
-better see the maxillary sinus
What initial imaging study you would you obtain for:
-TIA or acute stroke
- CT initially to distinguish ischemic from hemorrhagic
- MRI (more sensitive) to follow
what is a protrusion in disc disease?
- nucleus pulposis pushes focally through fibers of annulus fibrosis
- Base wider than apex**
- May focally impinge on nerve or thecal sac
what contrast is used in PET scans of the head?
radiolabeled glucose (F-18-FDG)
site of dilated loops in mid-abdomen can possible be caused by:
ulcer, renal stone
wht is the most common cause of small bowel obstruction
post-surgical adhensions
what is the contrast material used for a GI fluoroscopy studies?
barium (or iodine w/ ERCP)
what is fluoroscopy and when is it typically used?
- Real time images produced by mobile table producing x-rays and converting images into video
- For GI studies, barium is used as a contrast material
- Very active examination (think about the patient’s condition and ability to cooperate)
- Significant radiation dose
what gases can you see in the colon on plain film
- Almost always air in the rectum or sigmoid colon
- Usually no air-fluid levels
- Stool shows multiple small gas bubbles
- greater than 6 cm colon, greater than 8 cm cecum = Abnormal
indications for a MRI w/ a HA
- Thunderclap headache (CT if unstable)
- Headache that:
- worsens with exertion
- is associated with a decrease in alertness
- is positionally related
- awakens one from sleep
- changes in pattern over time - New HA in HIV positive individual
- HA with papilledema
- HA with focal neurologic deficit
- HA with mental status changes
*CT is acceptable if MRI contraindicated or unavailable
when would you order an non-contrast abdominal CT
- Kidney Stones
- Retroperitoneal bleed
- Contrast Allergy
- Acute Renal Failure
- Cr less than or equal to 1.5 concerning
- Diabetes
what 3 questions do you need to ask when assessing bowel obstruction on a plain film?
- Is there air in the rectum or sigmoid?
- Are there dilated loops of small bowel?
- Are there dilated loops of large bowel?
How can you get a plain film to assess GI/abdomen and when would you get those?
- Supine abdomen: Inappropriately called a KUB (kidney, ureters, bladder)
- Upright abdomen: better-Ability to assess for pneumoperitoneum (free air)
- 3-way: best- Upright chest, upright abdomen, supine abdomen (Requires a somewhat mobile patient)
subdural hematomas are typically caused by what mechanism?
- Deceleration injuries (ie. MVA)
- falls in elderly
- *more common than epidural hematoma
Common indications for plain film of skull
- Evaluation of penetrating injuries
- Location of foreign bodies
- Evaluate for the presence of depressed skull fragments
- Quick screening test for spinal trauma
- Evaluation of the pituitary fossa.
- Waters’ view still used in some settings for sinus evaluation
*largely replaced by CT and MRI
indications for an AP and lateral plain film for the spine
- Spondylolisthesis
- Compression fracture
- Sacroiliac (SI) joint disease
- Disc degeneration
- Facet arthritis
- Tumor
- Infection in disc space
how can clinical findings help differentiate localized ileus vs early SBO (sx 1-2 days) or partial SBO
-Early (symptoms of a day or two) or partial SBO will typically present with obstructive symptoms
- Localized ileus will typically present with signs/
symptoms of the underlying process (e.g. pancreatitis,
appendicitis, cholecystitis, etc.)
site of dilated loops in RUQ can possible be caused by:
cholecystitis
what contrast is typically used for MRI
gadolinium based
when treating low back pain, what should you recommend inregards to bed rest?
No more than 48 hrs
Complications of angiography
- Reversible neurologic deficit (TIA, RIND) 2-3%
- Permanent neurologic deficit (infarct) 0-5%
- Arterial occlusion 0-0.4%
- Arteriovenous fistula/pseudoaneurysm 0-0.22%
- Contrast media associated nephrotoxicity 0-0.15%
when do you see portal venous air
- severe GI inflammation
- ischemia
subarachnoid hemorrhages are typically caused by what mechanism?
- ruptured aneurysm (berry)
- trauma
- arteriovenous malformation (AVM)
PET scan of the brain allows for evaluation of what?
functional evaluation of the brain
- metabolism
- blood flow
- electrical activity
- neurochemisty
indications for imaging for back pain
- Conservative treatment for 6 weeks first unless there are “red flags”
1. Immediate imaging is recommended in patients with acute low back pain who have major risk factors for: - Cancer (unintentional weight loss, Immunosuppression, history of cancer)
- risk factors for spinal infection (intravenous drug use, steroid use)
- risk factors for or signs of cauda equina syndrome
- trauma history (esp with hx of Osteoporosis, or age greater than 50)
- severe or progressive neurologic deficits (Radiculopathy).
what is a functional ileus on plain film
One or more loops of bowel lose their ability to propagate peristaltic waves, causing
a functional “obstruction” proximally, seen as gas-filled loops of bowel
what is an ERCP?
- Combines endoscopy and fluoroscopy
- Endoscopically-guided cannula is inserted through the Ampulla of Vater and contrast is injected into the bile ducts and/or pancreatic duct
how do you differentiate the colon vs small bowel on plain film?
- Colon is peripherally positioned and has HAUSTRATIONS,
folds usually don’t go all the way across the lumen and
are more widely spaced
- Small bowel is centrally positioned VALVULAE CONNIVENTES, folds traverse entire width of lumen
what are the indications for an esophgram (fluoroscopy study)? and what pathology can it detect?
Indications: dysphagia, odynophagia, reflux (may be reasonable alternative to EGD- sedation, expensive, greater risks)
Pathology: Reflux (common), hiatal hernia (common), aspiration, esophageal diverticulae, neoplasm, esophagitis
what sinuses and landmarks can you see on a PA view of a plain film of skull
- Sphenoid sinus
- Maxillary sinus
- mastoid air cells
- hard plate
- nasal septum
___% will resolve without intervention (or imaging), most without a specific diagnosis
-Among patients with sciatica, ___ % will need surgery
90%
less than 10%
site of dilated loops in RLQ can possible be caused by:
appendicitis
what masses could you see in the abdomen on plain film?
- Hepatosplenomegaly
- Tumors (ovarian)
- Pancreatic pseudocyst
- Ascites (not really a mass)
what imaging would you initally order for an acute stroke and why
CT w/o IV contrast
- Rapid
- Reliable to exclude hemorrhage
- High sensitivity for acute blood
- Acute blood appears bright on CT relative to brain tissue.
what is a subarachnoid hemorrhage
- hemorrhage into subarachnoid space
* worst HA ever/sudden onset–> usually from berry aneurysms
what is a extrusion in disc disease?
- nucleus material pushes out beyond posterior longitudinal ligament but remains in contact with disc space
- Apex wider than base**
- Likely to impinge on nerve roots
how do you determine if there is a pneumoperitoneum?
-Best seen in upright film beneath hemidiaphragms
- Rigler’s sign: Both walls of the bowel visible: Best
seen in supine, usually only if large amounts of free
air
indications of a head/CNS CT
- Trauma (fracture, intracranial hemorrhage, contusion)
- Acute intracranial hemorrhage (2° to trauma, aneurysm, AVM)
- Hydrocephalus
- Intracranial infection (meningitis, encephalitis, toxoplasmosis)
- Suspected mass (neoplasm)
- Acute venous/dural sinus thrombosis
What initial imaging study you would you obtain for:
-Mass
MRI
what advantages and disadvantages of a CT to assess appendicitis?
Advantages: more sensitive, allows evaluation for other diagnoses
Disadvantages: IV contrast, exposure to ionizing radiation
what advantages and disadvantages of an U/S to assess appendicitis?
Advantages: low cost, availability, safe in pregnancy
Disadvantages: much less sensitive, children may lack sufficient visceral fat
What initial imaging study you would you obtain for:
-New-onset seizure
MRI
what pathology can an abdominal CT detect?
- Trauma
- Cancer
- Infection/Abscess
- Bowel Obstruction
- Appendicitis
- Diverticulitis
- Pancreatitis
- kidney stones
- angiography
what imaging would you order if someone presents with:
-Sensorineural hearing loss
MRI of posterior fossa,
temporal bone CT
what do MRIs of the back typically show in adults
- degenerative changes in many over 40
- many asymptomatic people have disc budlges and protrusion
*So, imaging is likely to result in an abnormal report.
But correlation between radiographic findings and clinical symptoms is poor.
what gases can you see in the stomach on plain film
- Gastric bubble normally present
- Air-fluid level visible on upright film
what is the difference btwn single and double contrast w/ fluoroscopy studies?
- Single contrast uses just barium
- Double contrast uses barium and air (Allows better visualization of the wall of the lumen)
What initial imaging study you would you obtain for:
-multiple sclerosis
MRI
what are the meninges
3 layers that surround the brain and spinal cord
- Dura Mater
- Arachnoid
- Pia mater
*CSF is between arachnoid and pia mater
what is a mechanical bowel obstruction?
A physical, organic
obstructing lesion prevents the passage of intestinal contents past the point of obstruction
what is the purpose of the contrast dye in flurosocopy of the spine?
Contrast media (dye) is injected into the cerebrospinal fluid (CSF). The contrast serves to illuminate the spinal canal, cord, and nerve roots during imaging
SBO vs localized ileus
Localized ileus
- GAS IN RECTUM OR SIGMOID
- 2-3 persistently* dilated loops of bowel
- same over time and regardless of veiw
SBO:
- GIVEN ENOUGH TIME, THERE SHOULD BE NO AIR IN SIGMOID OR RECTUM
- MULTIPLE (more than 3) dilated loops of SB
- may be associated w/ high-pitched hyperactive BS
*Localized ileus may resemble early (symptoms for 1-2 days) SBO or partial SBO on plain film (clinical findings may help here)
what is the common CT technique for common CT exams
- “Routine” – 3 hour oral prep, IV contrast
- CT appy – 1 hour oral prep, rectal contrast, IV contrast
- CT KUB – no contrast
*always give appropriate hx when ordering (what you suspect) so the radiologist can protocol it correctly
what are the indications for a SB follow through fluoroscopy study? and what pathology can it detect?
Often done in conjunction with upper GI
Indications: IBD, partial SBO, unexplained GI bleed
Pathology: Crohn’s disease, lymphoma, TB, sprue, adhesions, partial/intermittent obstruction
how is small bowel obstruction seen on a plain film?
Dilatation of bowel proximal to the obstruction. If complete obstruction, minimal or no air in distal bowel
- multiple air-fluid levels
- “step ladder”
what is repeat back imaging recommended
in patients with new or changed low back symptoms
*Even positive findings of degenerative disease like disc extrusions and spinal stenosis are not urgent and will be treated conservatively at first
L-spine film-AP view shows a good view for what?
- vertebral body fx
- transverse process fx
- disc disease
Epidural Hematoma CT findings
- High-density (i.e. lighter on CT image), biconvex, LENS-SHAPED mass
- Most commonly in the temporoparietal region due to injury of the middle meningeal artery or vein
- Often referred to as “lenticular” or lens shaped
- Can show a midline shift
when would you get a plain film to assess the GI/abdomen
only when adjacent structures possess different densities can they can be distinguished
*unlike the chest, which contains wide variations in radiodensity, the abdomen contains structures which can be very difficult to distinguish
what do you assess in the lower chest on abdominal plain films?
- Lower lobe pneumonia can cause abdominal pain
2. Check for infiltrate, effusions
what are the indications for an abdominal CT?
indications: Abdominal pain, N/V, mass, trauma, obstruction symptoms, renal colic, dropping hematocrit
what are common indications for an MRI of the spine?
- Disc disease (degenerative, infection)
- Spondylolysis
- Congenital abnormalities (spinal stenosis, dysraphisms)
- Neoplasm (cord, meningeal)
- Infection (epidural abscess)
- Inflammation (MS)
Common indications for a brain MRI
- Definition of neoplasm (primary vs. metastatic)
- Infection (ventriculitis, empyema, abscess)
- Inflammation (sarcoidosis, vasculitis)
- Demyelinating diseases (MS, Alzheimer’s)
- Trauma (DAI)
- Vascular malformations (AVM, varix)
- Posterior fossa lesions (schwannoma)
indications for flexion/extension plain film for the spine
- instability
what imaging would you order if someone presents with:
-Suspected neoplasm
MRI
when is fluoroscopy used to assess the spine?
- Fluoro-guided lumbar puncture
- fluoro-guided Myelogram (aka myelography)
what can you see/assess in a plain film of the GI/abdomen
The BIG 4 (and the other 2)
Gasses
Masses
Calcifications
Solid organs (liver, kidneys, spleen)
Bones
Lower chest
what structures does an abdominal CT assess
All solid viscera, all hollow viscera, free air, free fluid
what is a pneumobilia and when do you see it
-gas in biliary system
-often post ERCP; cholangitis,
emphysematous cholecystitis, gallstone ileus
when would you not get imaging for a seizure?
- Otherwise healthy children
- Febrile seizures
- Chemical withdrawal
what gases can you see in the small bowel on plain film
-Usually a small amount of air in 2-3 loops of bowel
-RULE OF THREE’S:
-greater than 3 air-fluid levels
-greater than 3 cm lumen
- greater than 3mm fold/
wall thickness
= Abnormal
indications for an oblique plain film for the spine
- Spondylolysis
- Facet arthritis
- Foraminal stenosis (cervical spine)
What initial imaging study you would you obtain for:
-depressed skull fracture, facial fracture
CT
what sinuses and landmarks can you see on a lateral view of a plain film of skull
- Frontal sinuses
- Sphenoid sinuses (below Sella turcica)
- vascular grooves
- pinna of ear
- mastoid air cells
4 categories of gas patterns
bowel obstruction
- Localized functional ileus
- Generalized (“adynamic”) functional ileus
- Small bowel mechanical obstruction
- Large bowel mechanical obstruction
L-spine film-oblique view shows a good view for what?
- facet joint disease
2. spondylolysis
what does an “apple core” lesion suggest on a barium enema?
colon CA
What initial imaging study you would you obtain for:
-acute hemorrhage
CT
what is a localized ileus on plain film
- One or two loops of bowel (“sentinel loops”), usually small bowel, due to local inflammation.
- “Sentinel loops” may suggest the site of an inflammatory or irritative process.
what are common indications of a PET scan (nuclear medicine) of the head
- Epilepsy
- Dementia—Separate dementia of Alzheimer’s type from other causes and pseudodementia due to depression.
- Neoplasm evaluation—Evaluation of residual/recurrent tumor after chemotherapy/radiation therapy
What initial imaging study you would you obtain for:
-Aneurysm or AV malformation
MRI
Subarachnoid hemorrage CT findings
- Blood (hyperintense) within sulci, Sylvian fissure, basal cisterns
- By 2-3 weeks, usually difficult to discern
-plain film shows slippage of one vertebral body on the one below
-Fracture of the pars interarticularis
“Scotty dog sign”
Spondylolisthesis
what imaging would you order if someone presents with:
-pulsatile tinnitus
- MRI w/ MRA and MRV
- Angiography (conventional or CT)
what are the indications for an ERCP fluoroscopy study? and what pathology can it detect?
Indications: Recurrent or chronic pancreatitis, obstructive jaundice, sphincter of Oddi dysfunction
Pathology: Obstruction (stones, strictures, sphincters), bile duct tumors
the bowel reacts to obstruction in the following 3 ways:
- Peristalsis continues
- Loops proximal to the obstruction become dilated with air and fluid
- Loops distal to the obstruction become decompressed or airless
what are the indications for a barium enema fluoroscopy study? and what pathology can it detect?
Indication: Hematochezia, Heme positive stools, abdominal pain, constipation, incomplete colonoscopy, suspected intussusception in a child (therapeutic, air only)
Pathology: diverticulosis, polyps, colorectal carcinoma, ulceration (IBD),
*Contraindicated in diverticulitis.
what fluoroscopy studies use barium (or iodine) as a contrast material
- Esophagram (“barium swallow”)
- Upper GI
- Small bowel follow through
- Barium enema
- ERCP (Endoscopic retrograde cholangiopancreatography)– uses iodine
what to assess on L-spine film- lateral view
- Contour lines of anterior and posterior vertebral bodies.
- Height and shape of vertebral bodies should be uniform.
- Disc spaces should be roughly equal in height.
what are indications for an angiography?
- Definition of atherosclerotic occlusive disease.
- Evaluation of aneurysms
- Trauma to cervicocerebral vessels
- Evaluation of tumor vascularity
- Evaluation of vasculitis
what imaging would you order if someone presents with:
-facial fractures
- Simple fractures may be visualized on plain films
- Multiple fractures usually require CT
causes of acute back pain
- paraspinal muscles and ligaments
- synovial joints
- disc disease
- spondylosis
- bone disease
- infection
what head bleeds do NOT cross suture lines?
epidural hematoma – bc dura is fused to skull at sutures
what structures do the following assess:
- Barium enema
- SB follow through
- upper GI
- esophagram
- Barium enema: colon and rectum
- SB follow through: jejunum, ileum, terminal ileum, cecum
- upper GI: esophagus, stomach, duodenum
- esophagram: Oropharynx, hypopharynx, esophagus, GE junction
what are general indications for fluorosocpy?
- Dysphagia
- GERD
- Intussusception or mesenteric volvulus in kids!
- Suspected Ulcer
- Suspected small bowel lesion (malabsorption, unexplained GI bleed, IBD)
- Colon cancer screening
- Suspected fistula
when would you order an MRI of the abdomen?
- Used much less commonly than CT
- Good for adrenal pathology
- Great for biliary pathology (MRCP)
- Great for female pelvis
- Often done for pre-transplant planning
- MR Angiography a good alternative to invasive angio
what imaging would you order if someone presents with:
-Sinusitis
noncontrast CT
the fifth most common reason for all physician visits
low back pain
*more than 75% of adults will suffer it at some time
abdominal CT caveats
- Radiation exposure: One CT of the abdomen = roughly 500 chest X-rays
- IV contrast can be toxic to the kidneys (Check serum creatinine first and Patients must not be on metformin)
what structures does an ERCP evaluate
biliary and/or pancreatic ductal systems
what is an angiography
- Catheter is passed through an artery leading to the body area of interest
- Contrast material is injected to highlight the vessels when x-rays are taken.
What initial imaging study you would you obtain for:
-major head trauam
CT (if neurologically unstable); MRI (if stable)
common indications for head/CNS imaging
- low back pain
- radiculopathy
- HA
- Stroke/TIA
- Vertigo
- Seizure
- Demenita
what is an epidural hematoma
- hemorrhage into potential space between dura and skull
- lucid interval initially (talk and die syndrome)
- tear in middle meningeal artery
what do Sentinel loops suggest
site of an inflammatory or irritative process
*seen in localized ileus
site of dilated loops in LLQ can possible be caused by:
diverticulitis
what head bleed is associated w/ a skull fracture 90% of the time?
epidural hematoma
