Name the tumor based on findings from plain radiographs of mandible: 1. sunburst appearance, radiating periosteal new bone 2. soft tissue mass with amorphous "popcorn" calcifications 3. displaced surrounding structures, with multiple loculations and a honeycomb appearance 4. well-circumbscribed lesion with a dense core and lucent rim; the core enlarges and rim diminishes with maturation

1. osteosarcoma 2. chondrosarcoma 3. ameloblastoma 4. cemento-ossifying fibroma

20 Imaging Studies Flashcards by brian langford

What is the imaging modality of choice for lymphatic malformations?

MRI. CXR can also r/o mediastinal extension or pleural effusion

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Arteriography before surgery is recommended for stable injuries to which neck zones?

I and III

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What is the initial test of choice in pts w/ pulsatile tinnitus and nl otoscopy?

Duplex carotid u/s and echo in pts suspected of carotid/coronary artery dz; otherwise, MRI/MRA/MRV brain and neck

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What is the initial test of choice in pts w/ pulsatile tinnitus and retrotympanic mass

CT scan of the temporal bone

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A 45-year-old woman with type I diabetes comes into the emergency room with severe left otalgia. She has been on topical ciprofloxin eardrops for the past 2 weeks without improvement. On examination, she has significant swelling of the pinna and external auditory canal (EAC) and granulation tissue is seen in the lateral portion of the canal. What imaging studies should be ordered?

CT w/ contrast and technetium-99m bone scan to evaluate for osteomyelitis of T bone

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A 54-year-old man presents with high fever, nausea, hypotension, and severe left-sided headache. Two weeks ago he was treated for left otitis media with azithromycin. On examination, he has severe edema and erythema over his left mastoid. Noncontrast CT scan of the brain shows the delta sign and contrast CT scan of the brain shows the reverse delta sign. What test should be ordered next?

MRI with gadolinium and MRV brain to confirm sigmoid sinus thrombophlebitis

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Pt with zenkers on swallow study. What would esophageal manometry show

Lack of coordination b/w pharynx and CP muscle, hypertensive UES, hypotensive LES, abnl esophageal peristalsis

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What finding on barium swallow is classic for CP dysfunction

CP bar

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Criteria for dx retropharyngeal abscess on lateral neck film

7 mm or greater thickness of the retropharynx at the level of C2 or 22 mm or greater thickness of the retropharynx at C6

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How is atlantoaxial subluxation diagnosed?

Neck pain and torticollis with an atlas-dens interval of > 4 mm in kids and > 3 mm in adults

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What radiographic view on plain film of the face is best for visualizing the zygomatic arches?

submental vertex

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What percent of cervical esophageal perfs will be missed with water-soluble contrast agents

50%

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What percent of thoracic esophageal perfs will be missed with water-soluble contrast agents

25%

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What is the sensitivity of barium in detecting esophageal perfs

80-90%

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What is the sensitivity and specificity of inspiratory/expiratory and lateral decubitus films for foreign body aspiration

67% sensitive and specific

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Name the tumor based on findings from plain radiographs of mandible:

sunburst appearance, radiating periosteal new bone
soft tissue mass with amorphous “popcorn” calcifications
displaced surrounding structures, with multiple loculations and a honeycomb appearance
well-circumbscribed lesion with a dense core and lucent rim; the core enlarges and rim diminishes with maturation

osteosarcoma
chondrosarcoma
ameloblastoma
cemento-ossifying fibroma

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On CT temporal bone, what ear structures are best seen on axial views

Body of malleus and incus
IS joint
Round window

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On CT temporal bone, what ear structures are best seen on coronal views

Stapes
Oval window
Vestibule

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On CT temporal bone with axial cuts, what structures are seen in same plane as porus acousticus

Head of malleus
Horizontal SCC
Epitympanic recess

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On CT temporal bone with axial cuts, what is seen in same plane as stapes

Sinus tympani
Handle of malleus
Vestibule
Cochlea
Pyramidal eminence

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What is m/c identified inner ear malformation on temporal bone imaging studies?

Isolated lateral SCC defects

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What temporal bone malformation is classic for rubella

Scheibe malformation

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“A 7-year-old boy is found on examination to have stenosis of his right EAC. CT scan shows ground glass appearance of the temporal bone. What is the likely diagnosis?

Fibrous dysplasia

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CT on 6-year-old boy with hearing loss. Findings include absence of the anterior 1½ turns of the cochlea, a normally developed basal turn, wide vestibular aqueduct, plumb-deformed vestibule, and “empty cochlea.” What is the likely diagnosis?

Mondini malformation

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How does otosclerosis appear on CT

“Early on, areas of deossification, in particular, a double low attenuation ring paralleling the cochlear turns and lucencies along the margins of the oval window are present. As the disease progresses, foci of denser bone develop, eventually resulting in obliteration.

What other disease can mimic otosclerosis radiographically

Paget's disease and osteogenesis imperfecta

What distinguishes otosclerosis from Paget's dz radiographically

“The radiographic changes are more extensive and pronounced with Paget’s disease; they are also more likely to be bilateral and may include narrowing of the internal auditory canal (IAC).

DDx of soft tissue mass on promontory

- Congenital cholesteatoma - Paraganglioma - Aberrant carotid - Persistent stapedial artery - Glomus tympanicum

What is the accuracy of CT imaging in detecting bony erosion

85%

“A 49-year-old woman comes in with headache and unilateral rhinorrhea. CT scan of the brain and sinuses shows an enlarged foramen cecum, crista galli erosion, increased interorbital distance, and a mixed soft tissue and fluid density mass. What is the likely diagnosis?

encephalocele

“A 23-year-old man comes in with chronic nasal congestion, sneezing, sinus pressure, and rhinorrhea. CT scan of the sinuses shows a peripheral rim of low-density edematous mucosa surrounding homogeneous, high-attenuation material in the maxillary and ethmoid sinuses bilaterally with scattered calcifications and sinus wall expansion. What is the likely diagnosis?

AFS

A limited coronal CT scan of the sinuses is least sensitive for detecting dz in which sinus

frontal

“What percent of patients, asymptomatic with regard to their sinuses and undergoing CT scan of the head for other indications, have mucosal thickening of their sinuses?

24-39%

“How well do CT scan findings correlate with patient symptoms and endoscopic findings in patients with chronic rhinosinusitis?

“Positive endoscopic findings correlate well with positive CT scans, but only 71% of patients with negative endoscopic findings will have a negative CT scan. CT scan findings correlate poorly with patient symptoms.

Where does mucosal thickening most often occur on CT scans of sinuses

osteomeatal complex

What is the incidence of incidental ethmoid mucosal thickening on CT scans in kids

30%

Which plating material has been show to have significantly less streak artifact on CT

Titanium

T/F: CT scan of larynx underestimates stage of laryngeal CA

True

Why should radionuclide scanning precede CT scan imaging of thyroid gland

“CT scan contrast will linger in the thyroid gland for up to 6 months and interfere with radionuclide scanning.

Absolute CIs to MRI

pacemaker, metallic intraocular foreign body, intracranial aneurysm clips

What is a flow void

Complete lack of signal after contrast 2/2 moderate to high blood flow

How small of a lesion can MRI with gad detect

2 mm

How small of a lesion can fast-spin echo MRI detect

4-5 mm

What should be applied when using fast-spin echo MRI

Fat saturation (otherwise fat will remain bright on T2 images with fast-spin echo)

What is signal intensity of fat and water on T1 and T2 MRI

Fat: T1 - high; T2 - low Water: T1 - low; T2 - high

Which temporal bone structures are best visualized with T1 MRI

Nerves w/in IAC

Which temporal bone structures are best visualized with T2 MRI

Fluid-filled compartments

What problems can occur with MRI fat-suppression at skull base

Artifact, 2/2 air meeting soft tissue can obscure important anatomical detail i.e. foramina

“An asymptomatic patient has an incidental finding of a high signal in the left petrous apex on T1-weighted images. What is the significance of this finding?

Asymmetric pneumatization of petrous tip is present in 4% of pts; the high signal is from the bone marrow

How does CHL granuloma appear on MRI

High T1 and T2 signal

How does cholesteatoma appear on MRI

Intermediate T1, high T2

T/F: Cholesteatomas enhance w/ gad

False

What are the typical findings of meningioma on MRI

Broad based with dural tail sign on MRI with gad

Using MRI, how can one distinguish inflammation from tumor in the sinuses

“Tumor will be isointense on both T1- and T2-weighted images, while inflammation will be hyperintense on T2-weighted images.

What are typical MRI findings for hemangiomas

Serpentine high-volume flow voids surrounded by nonvascular soft tissue

“A 62-year-old woman comes in for cerumen removal. Medial deviation of her soft palate is noted incidentally on examination and the rest of her physical examination is unremarkable. MRI of the neck is likely to show what?

Deep lobe parotid tumor with a "dumbbell" shape as it extends into the parapharyngeal space

What are the indications for MRI in pt with tinnitus

“Unilateral unexplained tinnitus with or without hearing loss; bilateral symmetrical or asymmetrical hearing loss suspicious for retrocochlear etiology (poor discrimination, absent acoustic reflexes, acoustic reflex decay, abnormal auditory brainstem response).

What is the earliest gestational age that complete glottic atresia can be detected on u/s

22 wks

What would u/s show in a fetus with complete glottic atresia

“Distension of the airway and lung parenchyma; flattening of the diaphragm; edema of the placenta; compression of the heart, great vessels, and thoracic duct.

What are the advantages of u/s in eval of thyroid nodules

“Can detect nodules as small as 2–3 mm; can differentiate between solid, cystic, or mixed nodules with >90% accuracy; can detect the presence of lymph node enlargement.

What findings on thyroid u/s are a/w inc risk of malig

“Irregular/indistinct margins, heterogeneous nodule echogenicity, intranodular vascular images, microcalcifications, complex cysts, and diameter >1 cm.

How does PET/SPECT work

Radionuclide metabolic substrates are injected intravenously and detected by either production of positrons (PET) or by a directionally sensitive gamma camera (SPECT)—metabolically active tissues light up.

What substrate is used in LN functioning imaging

Superparamagnetic iron oxide coated dextran

What is FDG

“Fludeoxyglucose; a glucose analog with the radioactive isotope fluorine-18 substituted for one of the normal hydroxyl groups on the glucose molecule. It competes with glucose to enter into metabolically active cells. Like glucose, it is phosphorylated inside the cell, but unlike glucose-6-phosphate, FDG-6-phosphate cannot undergo further metabolism and becomes trapped.

What is the 1/2 life of FDG

20% is excreted quickly by renal system; 80% remains in the tissues with 1/2 life of 110 minutes

What is SUV

Standardized uptake value; ratio of FDG concentration in a region of interest to its concentration in the whole body

“True/False: PET scans typically have minimal impact on T-staging following conventional assessment of head and neck tumors.

“True: PET scans are more valuable for providing additional information in relation to nodal and distant disease staging.

Which type of tumors in H&N are less likely to be detected by FDG-PET

Salivary gland tumors and tumors with a large amount of necrosis

“In patients with an unknown primary of the head and neck, how useful is a combined FDG-PET/CT scan in detecting the primary tumor site?

Will ID primary in approximately 35% of cases

“Which imaging device has the highest sensitivity and specificity for identifying and delineating residual and recurrent tumors of treated head and neck cancer?

Combined FDG-PET/CT scan

What percent of cold, warm/cool, and hot nodules on radioiodine scanning of thyroid gland are malig

17, 13, and 4%

What is the most useful application of thyroid scanning in pts with thyroid CA

to detect residual thyroid tissue or occult distant mets after thyroidectomy

Which cardiovascular med will interfere with radioiodine scanning

Amiodarone

What is the optimal TSH value prior to radioiodine therapy

30 mU/L or higher

After ablation rx, how often are repeat scans performed

6-12 months after ablation then every 2 yrs

What is m/c longterm SE of RAI

Decreased saliva production

How long after ablation rx should woman avoid getting pregnant

1 year

What study prior to reoperation for persistent or recurrent hyperparathyroidism

99Tc sestamibi is 85% sensitive in experienced centers; accuracy is increased if pt is placed on cytomel prior to the scan to suppress thyroid uptake

What imaging study is used to monitor the response to therapy for osteomyelitis

Gallium-67 scan