Radiology Notes

My notes during radiology residency, fellowship, and beyond…

Archive for the ‘ct’ Category

Acalculous Cholecystitis CT criteria

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2 major or 1 major + 2 minor

Major criteria:

  • Gallbladder wall thickening greater than 3 mm
  • Subserosal halo (ie, gallbladder wall edema)
  • Pericholecystic fatty inflammation
  • Pericholecystic fluid (without ascites or hypoalbuminemia)
  • Mucosal sloughing
  • Intramural gas

Minor criteria:

  • Gallbladder distention (>5 cm transverse)
  • High-attenuation bile (sludge)

Written by lmwong

December 19, 2009 at 2:18 am

Posted in abdomen, ct, gallbladder, gi

Acute Ischemic Stroke

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Cytotoxic edema is cell death with efflux of K and influx of Ca, Na, and water. Edema peaks at day 7.

CT noncontrast

  • Hyperdense artery sign on brain windows = thrombus; MCA most common (asymmetric)
  • Loss of gray-white matter distinction, loss of insular ribbon;
  • Parenchymal hypodensity = edema/cell necrosis
  • Gyral swelling = 12-24hrs
  • Hemorrhagic transformation = 24-48hrs
  • if negative, get MRI
MRI
  • Perfusion defect = ADC dark, DWI bright
  • Edema = T1 low, T2 high
  • if MRI negative and still strong clinical suspicion, do MRA or CTA neck/head

Stroke Timing

Time CT MRI
Minutes no change absent flow void, arterial enhancement, DWI high
2-6 hrs hyperdense artery sign, insular ribbon sign brain swelling (T1), subtle T2 high
6-12 hrs sulcal effacement, decreased attenuation T2 high
12-24 hrs decreased attenuation T1 low
3-7 d max swelling
3-21 d gyral enhancement
30-90 d encephalomalacia, loss of enhancement

Which vessel territory?

Causes of acute stroke by age group
Pediatrics
  • CHD
  • Blood dyscrasias
  • meningitis
  • arterial dissection
  • trauma
  • extracorporeal membrane oxygenation (ECMO)
  • venous thrombosis
Young Adult
  • Cardiac emboli
  • ASD
  • drug abuse
  • arterial dissection
  • coagulopathy
  • venous thrombosis
Elderly
  • ASD
  • cardiac emboli
  • coagulopathy
  • amyloid
  • vasculitis
  • venous thrombosis

Written by lmwong

April 12, 2008 at 3:12 pm

Posted in ct, mri, neuro, stroke

C-Spine CT Dictation

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Indication: Neck injury.

Technique: Multiple contiguous 3 mm axial images were obtained from the skull base through the thoracic inlet without intravenous contrast. Reformats in the coronal and sagittal planes were also obtained.

Comparison: [x]

Findings: No prevertebral soft tissue swelling is seen. The cervical alignment is maintained without spondylolisthesis. No acute fracture is identified. The vertebral body and disk space heights are preserved. The odontoid process is intact.

Impression: [x]

Written by lmwong

April 9, 2008 at 11:01 am

Posted in ct, neck, neuro, sample dictation

Petrous Temporal Bone CT Dictation

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Indication: [x]

Technique: A CT of the petrous temporal bone was obtained utilizing multiple contiguous 1 mm axial and coronal images without the use of intravenous contrast. Sagittal and coronal reformats were also obtained.

Comparison: [x]

Findings: The external auditory canals, tympanic membranes, and osseous labyrinths are normal bilaterally. There is no evidence of erosion of the ossicles, scutum, or tegmen tympani. The mastoid air cells are well-pneumatized and well aerated. No suspicious osseous lesion or fracture is identified.

Impression: Normal petrous temporal bone CT.

Written by lmwong

April 9, 2008 at 11:00 am

Neck Soft Tissue CT Dictation

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Indication: [x]

Technique: Contiguous 3mm axial images were obtained from the skull base to the thoracic inlet following the administration of intravenous contrast.

Comparison: [x]

Findings: The nasopharynx, oropharynx and hypopharynx are normal. No cervical mass or collection is seen. No aerodigestive tract mass is identified. The parotid, submandibular and thyroid glands are normal. No lymphadenopathy is identified. The osseous structures are intact.

Impression: Normal neck CT.

Written by lmwong

April 9, 2008 at 11:00 am

Posted in ct, neck, neuro, sample dictation

Facial CT Dictation

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Indication: Facial injury.

Technique: A facial CT was performed utilizing contiguous 3 mm axial images with reformats in the coronal and sagittal planes. No intravenous contrast was administered.

Comparison: [x]

Findings: The paranasal sinuses are well-developed and aerated. There is no mucosal disease or air-fluid level. The cribriform plate appears intact. The nasal septum is not deviated. No osseous lesion or fracture is visualized.

Impression: Normal facial CT.

Written by lmwong

April 9, 2008 at 10:59 am

Head CT Dictation

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Indication: [x]

Technique: Multiple contiguous 5 mm axial images were obtained from the skull base to the vertex without the use of intravenous contrast.

Comparison: [x]

Findings: The ventricles and sulci are within normal limits. No intracranial hemorrhage or extra-axial fluid collection is identified. There is no evidence of acute territorial infarct, focal mass lesion or midline shift. The osseous structures are intact. The paranasal sinuses are well-aerated.

Impression: Normal head CT.

Written by lmwong

April 9, 2008 at 10:58 am

Posted in ct, head, neuro, sample dictation