Cholesteatoma- HRCT

Non contrasted temporal bone CT reveals a soft tissue mass in the right middle ear and Prussak’s space with associated erosions of the scutum, epitympanum walls, lateral semicircular canal, tegmen tympani and middle ear ossicles. It is also extending in to the mastoid air cells.

Discussion:

• An acquired cholesteatoma is a collection of exfoliated squamous epithelium and debris.
• Cholesteatomas often begin at the pars flaccida of the tympanic membrane and grow in Prussak's space of the temporal bone and produce inflammatory reaction.
• Cholesteatomas typically occur in the setting of chronic dysfunction of the Eustachian tubes and recurrent otitis media.
• Cholesteatomas can be as small as a couple of millimeters in size or can grow to fill the entire middle ear.
• Erosions of the scutum and ossicles are commonly seen.
• The presence of bony erosions or expansion are strong support of cholesteatoma over chronic otomastoiditis.
• Acquired cholesteatomas occur in children and adults.
• Most common presenting symptoms include ear discharge, hearing loss, ear pain and vertigo.
• Without treatment cholesteatomas will progressively increase in size.
• Complications include: Hearing loss, CN 7 palsy, venous sinus thrombosis, semicircular canal fistulas, and intracranial invasion.
• Early surgical intervention usually results in complete eradication and preservation of hearing.

Differential diagnosis:

1. Acquired cholesteatoma
2. Chronic otomastoiditis
3. Middle ear cholesterol granuloma
4. Glomus tympanicum paraganglioma

Double left renal artery - CT Angiography

44 Year old female referred for CT renal angiography for transplant donor evaluation. The coronal volume rendering images showing normal bilateral kidneys with single right renal artery and two renal arteries on the left side.

Discussion:
CT angiography is the most preferred investigation for donor kidney evaluation since it gives excellent anotomical depiction of the vessels, organs and the function of kidney in urography.
Protocol - Arterial phase, Venous phase and Excretory phase.
The things to be mentioned in the radiological report are

• Size, shape and position of the kidneys.
• Number of renal arteries, any accesory artery.
• Course of left renal vein retroaortic /preaortic.
• Distance of renal artery from origin to first branching.
• Length of right renal vein.
• Any other normal varuients/renal masses.
• Collecting system - Duplication of any.

All these findings are valuable to the graft harvesting surgeon and for the transplant anastomosis.

The Azygos Lobe

55 year old male came with history of chronic cough and was reffered for CT scan to ruleout tuberculosis and any other lung disease. CT scan axial section (first image) shows a azygos vein is coursing through the apical segment of the right upper lobe (arrow). Coronal reformated image shows pleural reflection - mesoazygos (arrow) with azygos vein (arrow head) in the right apical region.

Discussion:

The azygos lobe is a rare anomaly that developmentally arises when the right posterior cardinal vein penetrates the apex of the lung, instead of passing over it, and travels inferiorly taking pleural layers with it to entrap a portion of the right upper lobe. The two folds of pleura form the mesoazygos, a fissure visible on 0.4% of chest radiographs and 1.2% of high resolution computed tomography (CT) studies. The right azygos lobe is supplied by the medial segments of the apical and anterior or posterior branches of the apical segmental bronchial artery and vein. A true left azygos lobe has also been reported.
On chest radiography, the azygos lobe is usually distinguished by the azygos fissure, which superiorly has a triangular shape and inferiorly demonstrates the azygos vein as a tear-shaped shadow. The azygos fissure typically appears as a fine, convex line that crosses the apex of the right lung. The azygos lobe can appear opaque and be incorrectly interpreted as a pathologic mediastinal finding on PA chest radiographs.
When findings on traditional imaging are not clear, CT exams can be helpful in delineating relevant anatomy. Clinically, the knowledge of azygos lobe anatomy is important during thoracic surgical approaches. Partial obstruction of the thoracoscopic view during a bilateral sympathectomy was reported during attempted mobilization of the azygos lobe. Others reported difficulty reflecting the pleura during primary repair of the esophageal atresia in a pediatric patients. There are also reports of the phrenic nerve coursing within the azygos fissure. Finally, multiple authors have reported spontaneous pneumothorax associated with the azygos lobe in both the adult and the pediatric patient.