Neuroradiology #37

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Clinical Data

40-year-old female presents with acute severe headache at the emergency department.
The neurologist wants to rule out an intracranial haemorrhage and orders a CT brain.

Showing images CT without contrast

More images: MRI

What do you see?

What do you see?

CT shows
* low attenuating suprasellar lesion (fat density) with rim calcification.
* multiple scattered smaller similar subarachnoid lesions supra and infratentorial.
* enlarged supratentorial ventricles.

MRI shows
* the suprasellar lesion shows T1 heterogenous and T2-hyperintense signal,
* multiple scattered T1-hyperintense foci subarachnoid and intraventricular in the left frontal horn (arrows).
* no enhancement.
* no diffusion restriction (not shown).

What is the most likely diagnosis?

What is the most likely diagnosis?

Ruptured suprasellar dermoid cyst.

Ruptured intracranial dermoid cyst

Intracranial dermoid cysts are often incidental findings and most do not cause symptoms. Both dermoid and epidermoid cysts are ectodermal in origin and lined by stratified squamous epithelium. In addition, dermoid cysts contain epidermal appendages such as sebaceous glands which secrete sebum, an oily substance.

Symptoms occur due to mass effect or rupture. In case of rupture, dermoid material (sebum droplets) can leak into the subarachnoid space which can lead to chemical meningitis and cause symptoms such as headaches, seizures, and vasospasms.
CT shows
-hypoattenuating primary lesion (fat density due to sebum).
-typically, not exclusively, in midline location.
-sometimes rim calcification of the primary lesion.
-smaller similar hypoattenuating lesions in the subarachnoid space in case of rupture.

MRI shows
-generally T1-hyperintense signal (sebum).
-scattered T1-hyperintense droplets in the subarachnoid space and intraventricular. Fat-fluid level within the ventricles.
-variable T2 signal.
-generally no enhancement of the lesion. Leptomeningeal enhancement in case of chemical meningitis.

References

https://radiopaedia.org/articles/intracranial-dermoid-cyst-1

Head and Neck #15

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What do you see in the following images?

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Scalp haemangioma
Right parietal subcutaneous well-defined soft tissue oval lesion. It demonstrates low signal on T1W image, Intermediate signal on T2W image with prominent vascular flow voids, and avid enhancement on the post contrast image. No adjacent osseous or soft tissue abnormality. No intracranial extension.

More information

Infantile hemangiomas are benign vascular tumours, most of these tumours arise in the craniofacial region. Most of them are not present at birth but they increase in size during the first year of life, with a subsequent progressive involution during early childhood.

Differential diagnosis includes: epidermoid cyst, lymphatic malformation,  and sinus pericranii.

Abdominal #22

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45-year-old female patient:

* Generally unwell with abdominal pain and palpable cervical lymph nodes

Clinical information:

– Newly diagnosed HIV infection with a very low CD4 count of 30 cells/uL
– Generally unwell
– Presents at the emergency department with abdominal pain and palpable cervical lymph nodes

What do you see?

Diagnosis:

Most likely pulmonary and extrapulmonary tuberculosis in an immunocompromised patient with miliary pulmonary lesions, tuberculous colitis and ileitis, and necrotic extrapulmonary adenopathy (cervical and abdominal adenitis)
Microbiological analysis of an excised abdominal node confirmed the presence of Mycobacterium tuberculosis

Treatment:

Ileocaecal resection, tuberculostatic medication, and HAART

Teaching points:

– Be aware of TB in immunocompromised patients
– Cervical nodes are the #1 site of extrapulmonary TB adenopathy and the most common cause of adenopathy worldwide
– Intestinal tuberculosis can mimic inflammatory bowel disease

Neuroradiology #36

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Clinical Information

A young adult male presents with progressive limb numbness and gait disturbances. Medical history was unremarkable.
MRI brain was performed and showed no intracranial abnormalities.
The neurologist ordered an MRI scan of the cervical spinal cord.

Showing MRI images:

What do you see?

A long segment T2-hyperintense lesion in the posterior part of the cervical myelum, specifically in the dorsal columns (‘inverted V-sign’). There is no perilesional oedema, mass effect, or enhancement.

What is the differential diagnosis based on the MRI findings?

Subacute Combined Degeneration due to Vitamin B12 deficiency or inactivation
Intrathecal MTX-induced myelopathy
Vitamin E deficiency
Copper deficiency
Tabes dorsalis (neurosyphilis)
HIV vacuolar myelopathy

More information
The laboratory values of Vitamine B12 were normal, as well as Copper and Vitamin E values.
HIV and Syphilis screening were negative.

The patient finally confirmed recreational (ab)use of nitrous oxide.

What is the most likely diagnosis?

Subacute Combined Degeneration due to nitrous oxide-induced Vitamin B12 inactivation.

Subacute Combined Degeneration

SCD is a neurological complication of vitamin B12 deficiency or inactivation. Several drugs can inactivate vitamin B12 such as metformin and nitrous oxide. Abuse of nitrous oxide inactivates vitamin B12 by oxidizing Cobalt-ion. In case of nitrous oxide abuse, vitamin B12 serum levels can appear normal.
Clinical symptoms include loss of vibration and proprioception in hands and feet and sensory gait ataxia. In severe cases, muscle weakness especially in the distal extremities can be seen.
MRI shows bilateral T2 high signal in the dorsal columns (inverted V sign) which explain the sensory deficits (paraesthesia, propriocepsis, and fine touch). In severe or untreated cases, the lateral columns may be involved leading to motor deficits such as limb weakness, spasticity, and paraplegia. The lesions typically involve a long segment in the cervical and higher thoracic spinal cord and show no enhancement or cord expansion.
It is crucial to promptly identify this disease and treat the vitamin B12 deficiency and/or discontinue the inactivating drug to prevent serious complications.

Abdominal #21

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86-year-old patient:

– With sudden collapse

Clinical information:

– Patient known with infrarenal aortic aneurysm
– Sudden collapse at home
– Transfer to the hospital with ambulance

Axial and coronal slices of an abdominal CT in 2019 show a tortuous abdominal aorta with aneurysmal dilatations and eccentric thrombus. There is a thrombosed saccular component at the level of the aortic bifurcation (arrow)

CT at presentation:

What is the diagnosis?

Diagnosis:

– Ruptured aortic aneurysm
* known infrarenal aortic aneurysm
* massive retroperitoneal hematoma extending into the posterior pararenal and perirenal compartments
* active contrast extravasation
– Point of weakness: saccular aneurysmal component

Teaching points:

– This case did not show a classic sign of pending rupture; however, a clear point of weakness was retrospectively identified (the saccular aneurysmal component at the aortic bifurcation)
– Radiological signs of pending rupture:
* !! High attenuating crescent (= acute haematoma within the mural thrombus or aneurysmal wall)
* Focal discontinuity of intimal calcification and ‘tangential calcium sign’
* ‘Draped aorta sign’, present when
* The posterior aortic wall is unidentifiable as a distinct line
* The posterior aorta follows the contour of the spine on one or both sides
– Reference: CT signs of pending aortic aneurysm rupture, J.P. Heiken, radiologyassistant.nl
https://radiologyassistant.nl/abdomen/aorta/aneurysm-rupture

Head and Neck #14

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What do you see in the following images?

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Nasolabial cyst
Right nasolabial lesion with remodeling of the maxillary alveolus bone. On MRI it shows high signal intensity on both T1- and T2-weighted images with no signal suppression on the T2 FLAIR with Fat saturation sequence.
Differential Diagnosis:
Nasolabial cyst with hemorrhage
Epidermal inclusion cyst
Dermoid cyst
Dentigerous cyst

Abdominal #20

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61-year-old female:
– With elevated ALT, AST, and bilirubin

What do you see?

What do you see?

Wall thickening and enhancement of the gallbladder wall
Mild common bile and intrahepatic duct dilatation
Filling defect within the distal common bile duct

Diagnosis:

Choledocholithiasis

Musculoskeletal #32

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53-year-old male:
– Persistent right shoulder pain, no movement limitations.
– No previous trauma.
– Shoulder MRI is performed

What do you see?

Click here to see more information

Quadrangular/Quadrilateral space syndrome
– Posteroinferior paralabral cyst (arrow) extending into the quadrangular space
– Teres minor mild fatty infiltration – atrophy (circle)
– Neurovascular compression syndrome of the posterior humeral circumflex artery (PHCA) and/or the axillary nerve or one of its major branches in the quadrangular space
– Multiple causes of compression: fibrotic bands, ganglion/cysts, aneurysms, tumours
– MRI may demonstrate atrophy and/or denervation edema of the teres minor and/or deltoid muscles
– Differential diagnosis: Parsonage-Turner sd, disuse atrophy

Abdominal #19

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A 79-year-old female patient:
– Presented with abdominal pain, nausea, vomiting
– Previous history of cholecystitis and pancreatitis
– Laboratory findings:
*Elevated C-reactive protein and white blood cell levels

What do you see?

Pneumobilia (arrow)

Cholecystoduodenal fistula (red arrow)
Gastric (blue arrow) and duodenal (green arrow) distension

Gallstone located in the proximal jejunal segment (red arrows)
Gastric distension (blue arrows)

What is your diagnosis?

Gallstone ileus


Abdominal CT images obtained two years earlier show that the gallstone is in the gallbladder (arrows).

Teaching points:

* Gallstone ileus is a cause of mechanical small bowel obstruction that generally affects the elderly and has high mortality. It is a rare complication of chronic cholecystitis. It develops when a gallstone passes through a cholecystoenteric fistula leading to small bowel obstruction.

* Gallstones most commonly become impacted in the distal ileum.

* The classical imaging findings on abdominal radiographs form Rigler triad: pneumobilia, small bowel obstruction, and ectopic radio-opaque gallstone

* CT is the most frequently used imaging modality for the diagnosis as it demonstrates the rim-calcified or total-calcified ectopic gallstone, abnormal gallbladder with air collection, presence of air-fluid level, biliary-enteric fistula, and transition point of small bowel obstruction. However, only a minority of gallstones are calcified. Therefore, they may be overlooked in intestinal lumen, which may result in misdiagnosis. Multiplanar reformatted CT images can be helpful to locate the migration site of the ectopic stones.

* Treatment: Surgery with removal of gallbladder stone is the definitive treatment.

In our case, the patient underwent surgery. Enterotomy with gallstone removal was performed. According to the operation note, the gallstone was located in the jejunum 20 cm distal to the ligament of Treitz.

Abdominal #18

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75-year-old female:
– Day 4 post Whipple procedure
– Ongoing abdominal pain with increased inflammatory markers and slightly increased lactate levels

What do you see?

– Post-operative changes following partial pancreatectomy and duodenojejunostomy (partially shown)
– Prominent mesenteric nodes
– Partially occlusive thrombus of the superior mesenteric vein (best seen on axial slice) extending to a large jejunal branch (seen on coronal slice)

What is the most likely diagnosis?

Partial SMV occlusion as a complication to recent Whipple procedure