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









