Random_1 Flashcards
Diaphanous
Light, delicate, and translucent.
Aggressive looking, ehancing extra axial mass
- meningioma
- hemangiopericytoma
- endolymph sac tumor (temporal bone)
- aggressive mets
Odontoma
- Most common odontogenic tumor
- Actually hamartomas
- Often their radiographic appearance is one of a conspicuously dense jaw lesion with a surrounding hypodense halo
- Often in the mandible and frequently interfere with the eruption of adjacent dentition
- Conservative resection is most often curative.
Acute disseminated encephalomyelitis
- Multifocal white matter lesions with relatively little mass effect or vasogenic edema
- Locations
- anywhere in the spinal cord
- brain is almost always involved
- T1: focal low signal intensity
- T2: multifocal flame shaped white matter lesions with slight spinal cord swelling
- T1 post gad: variable enhancement, may show punctate, rim, or fluffy enhancement
- Etiology
- viral infections
- vaccinations
- Rx: immunosuppressant
4 compartments of the orbital space
- ocular
- intraconal space
- extraconal space
- conal space (EOM)
Most common epithelial malignancy of the lacrimal gland
- adenoid cystic carcinoma (ACC)
- DDx
- pleomorphic adenoma
- orbital pseudotumor
- metastasis
- lymphoma
Most common benign epithelial tumor of the the orbit
benign mixed tumor (BMT) or
pleomorphic adenoma
- when compared to adenoid cystic adenoma - BMT/pleomorphic adenoma does not demonstrate bony erosion
Most common PRIMARY intraocular tumor in adults
- ocular melanoma
- melanocytes of the uveal tract - ciliary body, choroid, iris
- CT - hyperdense, slight to moderate enhancement
- MR - hyper T1, hypo T2
- DDx
- choroidal nevus
- choroidal hemangioma
- hypo to hyper on T1
- iso to hyper on T2
- metastatic choroidal lesion
Most common intraorbital tumor
- metastasis - often from breast cancer
- diffuse and irrgular
- grows along rectus muscles and fascial planes
Orbital hemangiomas
- well-defined, encapsulated lesions
- most often in the intraconal space
- rounded or oval in shape
- CT
- isodense to extraocular muscles on CT
- may be associated with calcificiations
- MR
- isointense on T1
- hyperintense on T2
- homogeneous, classic patchy enhancement
- DDX
- nerve shealth tumors and nerve sheath meningiomas - tubular in shape
- optic nerve glioma
- orbital varix - enlarge during valsalva maneuver
Orbital Wegener granulomatosis
- 2% of cases of WG
- MR
- HYPOintense to orbital fat on T1 and T2
- enhance strongly
- DDx
- orbital lymphoma
- metastases
- sarcoidosis
- orbital psuedotumor
Orbital inflammatory pseudotumor
- no predilection for age, sex, or race
- hypo to isointense to extraocular muscles, marked enhancement. No bone destruction
- DDx
- orbital cellulitis
- lymphoma
- sarcoidosis
- WG
Optic nerve sheath meningioma
- 40 yo, female predominant
- fusiform enlargement of the optic nerve sheath, with tramtrack sign
- CT
- hyperdense
- calcifications
- MR
- hypo, iso intense on T1
- variable on T2
- marked enhancement
Orbital lymphoma
- CT - hyperdense; no bony changes
- MR - hypointense on T1 and T2
- homogeneous enhancement
Etiologies for infectious terminal ileitis
- TB
- salmonella
- yersinia
- campylobacter
Most common primary appendiceal tumor
Carcinoid of the appendix
MR appearance of endometriosis
T1 hyper
T2 hypo
hemosiderin rim
Ovarian vein thrombosis
- most often idiopathic
- common causes
- postpartum patients
- after pelvic surgery
- pelvic trauma
- pelvic inflammatory disease
- complications of chemotherapy
Vogt’s triad of tuberous sclerosis
- mental retardation
- seizures
- adenoma sebaceum
Bioenteric intragastric balloon
BIB
- A BIB is a temporary weight-loss device
- CT - a large, round, fluid- and gas-containing intragastric structure
- Common adverse effects include nausea, vomiting, and abdominal cramps
- However, balloon migration, GI tract perforation, and obstruction
- Necrotizing pancreatitis is an uncommon complication
Cross fused renal ectopia
vs
Horseshoe kidney
- An anomaly where the kidneys are fused and located on the same side of the midline
- Normal ascent of the kidneys is required for formation of the extraperitoneal perirenal fascial planes and therefore ectopia (or renal agenesis) results in failure of development of fascial layers on the ipsilateral side –> malposition and medial displacement of the colon
- Left to right ectopy more common
- V.S. horseshoe kidney - fused with isthmus comprised of either renal parencyhmal tissue or fibrous tissue; with association with chromosomal syndromes and complications - reflux nephropathy and wilm’s tumor
Endometrioma
- T1 hyper, T2 hypo/grading
- homogeneous
- vs hemorrhagic cyst
- may have cholesterol depositions
Pseudocirrhosis
- In patients with cancer metastases to the liver, treatment with chemotherapy can result in areas of retracted tumor tissue and scarring. Between areas of scarring, the liver parenchyma is regenerative
- Unlike cirrhosis, at pathology patients do not have bridging portal fibrosis, but can manifest nodular regenerative hyperplasia
Normal MR signal intensity of the pituitary gland
- Anterior pituitary gland (Adenohypophysis) – isointense on both T1 and T2
- Posterior pituitary gland (Neurohypophysis) – high T1, low T2
- Post Gad – contrast washes into the gland from the infundibulum and gradually spread to the more peripheral parts of the gland
Pituitary Siderosis
- Hemochromatosis develops in patients with chronic hemolytic anemia undergoing chronic blood transfusions –> iron deposition in a variety of body organs.
- The susceptibility effect caused by accumulation of iron on certain MRI sequences leads to signal loss in the affected tissues.
- Hemochromatosis –> pituitary siderosis –> hypopituitarism
Define: recourse
A source of help in a difficult situation:
- “surgery may be the only recourse”.
- “sometimes the transverse colon may be visible on supine fluoroscopy without recourse to any other technical maneuveres to demonstrate the colon”.
Tract
vs
Track
- Tract: An AREA of indefinite extent, typically a large one: “large tracts of natural forest”
- Track: A rough PATH or minor road, typically one beaten by use rather than constructed.
Venous sinus thrombosis
- Unenhanced CT - hyperdense sinus
- CTV - empty detla sign; filling defect
- MR -
- Acute thrombus - iso T1, hypo T2
- Subacute thrombus - hyper on T1 and T2
- Venous infarct - hyper FLAIR
- Post-Gad - clots are hypointense with rim enhancement
3rd ventricle mass
- Lesions more anterior in the third ventricle are usually sellar-suprasellar or hypothalamic masses;
- posterior masses include pineal and tectal masses;
- inferior masses include hypothalamic hamartomas, basilar artery aneurysms, and arachnoid cysts.
- Intraventricular masses are most often from the choroid plexus and include papillomas, carcinomas, and lymphomas.
- Intraventricular masses not from the choroid plexus include chordoid glioma, ependymoma, meningioma, and craniopharyngioma.
Chiari II malformation
- open myelomeningocele
- leakage of CSF
- small posterior fossa
- not enough room for cerebellar development
- tonsillar ectopia, crowding of foramen magnum, upward shifting of vermis, beaking of tectal plate
Hypothenar Hammer Syndrome
Hypothenar hammer syndrome (HHS) refers to an abnormality of the ulnar artery thought to be caused by repetitive, blunt trauma to the hypothenar area. HHS is most prevalent in men with occupations that require repetitive hammer-like motion
Lipoleiomyoma
- Lipoleiomyoma is a rare benign uterine tumor, typically seen in postmenopausal women.
- US: a hyperechoic myometrial mass with a hypoechoic rim.
- CT: well-defined mixed fatty and soft-tissue uterine masses.
- MRI: demonstrate the fat content within the mass and confirm a uterine location.
- Uterine lipoleiomyomas may be mistaken for other pelvic pathology, especially ovarian teratomas.
- Recognition of lipoleiomyomas on imaging is important because they require no intervention.
Brink
An extreme edge of land before a steep or vertical slope.
A margin or bank of a body of water.
Persistent left SVC
- The persistent left SVC is usually a smaller vessel than the right.
- A solitary left SVC due to regression of the right is rare.
- The left-sided SVC most commonly drains into an enlarged coronary sinus.
- Rarely, it can drain into the left atrium, creating a right to left shunt.
- It is nearly always an asymptomatic and incidental finding.
US appearance of pseudoaneurysm
In a pseudoaneurysm, blood flow occurs within the mass, which is connected to the native artery by a neck.
A “to-and-fro” flow pattern is seen in the neck, with blood flowing into the collection during systole and away from the collection during diastole.
Duct of Luschka injury
- The duct of Luschka is an anatomic variant the has been described as a subhepatic duct that courses immediately adjacent to the gallbladder as well as an aberrant duct that empties directly into the gallbladder.
- It is an anatomic variant that once damaged, no longer drains as it did preoperatively, thus leading to a biliary leak.
- Treatment options include ERCP, Percutaneous biliary drainage (PBD) and repeat surgery. A percutaneous biliary drainage was performed diverting the bile thus allowing the duct to heal.
Wilson’s disease
- autosomal recessive
- copper metabolism
- hepatic dysfunction and profound neuropsychiatric symptoms are common
- copper deposition: liver, brain, eyes, kidneys, thyroid gland
- most affected areas: basal ganglia, thalami
- CT: decreased hypodensity
- MR: T2 hyper, restricted diffusion
- virtually pathognomonic of Wilson’s: pons and midbrain “face of the giant panda” sign on T2 axial imaging.
- unique geographic sparing of the red nuclei (“eyes”)
- pars reticulata of the substantia nigra (“ears”)
- superior colliculi (“nose”)
Signal voids on T2 images
- Calcifications - correlate with Xray or CT
- Vascular flow voids
Enchondroma
- second most common benign bone tumor (most common is NOF)
- cannot occur in the skull
- chondroid matrix characterized by rings and arcs calcifications
- intramedullary, may cause expansion of cortex without cortical break or periosteal reaction
- if cortical breakthrough or soft tissue mass seen, think of malignant transformation into a chondrosarcoma
- diagnosis can be made just on the basis of plain films and CT, MRI is helpful to evaluate the involvement and extent of the lesion
- MR demonstrates T2 hyper intensity and no contrast enhancement
- Signal voids compatible with calcification
Wilson’s disease
Face of giant panda sign
choesterol granuloma in petrous apex
Anatomy of lacrimal apparatus
Optic nerve sheath meningioma
- enhancing
- tram-tracking
- may contain calcifications
- may be associated with optic canal widening or hyperostosis
SLAP anatomy
Schatzker classification
Dorsal defect of patella
Salter-Harris classification
Avulsion fracture of the extensor digitorum brevis
- the muscle originates from the anterolateral aspect of the calcaneus
- frontal view of ankle best for Dx
- fracture fragment adjacent to the lateral margin of the calcaneus
- 2 cm distal to the lateral malleolus
Sinus tarsi syndrome
- sinus tarsi - anatomic compartment
- cone-shaped central and lateral space between the midpole of the talus and the anterior process of the calcaneus
- between the posterior subtalar joint and the talocalcaneonavicular joint
- contents: fat, neuovascular bundle, talocalcaneal ligaments
- sinus tarsi syndrome
- inflammation and hemorrhage within sinus tarsi
- lateral foot pain
- cause: inversion injury, rheumatoid arthritis
- abnormal MR which does not show fat density at this site
Persistent pain following trauma due to sinus tarsi syndrome
(a) T1 weighted sagittal image showing normal sinus tarsi containing the intertarsal ligament (arrow) and fat.
(b) T1 weighted sagittal image in a patient with sinus tarsi syndrome. The sinus is filled with abnormal tissue returning low signal intensity material (arrows).
Coxa valga/vara/norma
- normal femoral neck-shaft angle = 135
- coxa vara < 110
- coxa valga > 140
Best view for femoral neck fractures
Groin lateral radiographic view of the hip
allows best assessment of the femoral neck along its entire length without superimposition of the greater and lesser trochanters
