Epiploic Appendagitis

An axial CT image of a 43-year-old man with left lower quadrant pain shows an oval fatty mass (arrow) with surrounding fat stranding. There is fascial thickening (arrowheads).

Epiploic Appendagitis

• Torsion of epiploic appendages results in vascular occlusion, leading to ischemia
• Inflammation of appendages is self limited. Rarely, it may result in adhesion, bowel obstruction, peritonitis, or abscess
  
• Common in 4th to 5th decades of life
• Acute pain, most in left lower quadrant - easily mistaken for acute diverticulitis
  

CT Appearance

• Anterior to colonic lumen, sigmoid colon > descending colon > cecum
  
• Oval fatty mass surrounded by inflammation, 1.5cm and 3.5cm size
  
• Central high-density focus represents venous thrombosis
  
• Colonic wall thickening rare
  

Reference:
Singh AK. CT appearance of acute appendagitis. AJR Am J Roentgenol 2004;183:1303-1307.

Intracranial Aneurysms

Fig.1: Unenhanced axial CT of the head of a patient without recent trauma shows diffuse, bilateral subarachnoid hemorrhage (arrowheads), left greater than right. There is blood in the cerebral sulci as well as in the CSF cisterns.
Fig.2: Axial CT with IV contrast (angiographic technique) shows a left supraclinoid internal carotid artery aneurysm (arrow), measuring 6-7 mm.

Intracranial Aneurysms

• Dilatation or ballooning of intracranial blood vessel, small <12>25mm
• Three types: fusiform, saccular and dissecting
• Berry aneurysm is of a saccular type
• Common at branch points of large arteries that form the circle of Willis
• Anterior circulation (85% - 95%) > posterior circulation

Symptoms

• Most aneurysms are small and asymptomatic. Large ones may cause mass effect to cranial nerves and brain.
  
• Rupture usually results in subarachnoid hemorrhage (SAH) with high mortality of up to 50%
  
• Overall rupture risk is 1.9% per year, higher in women, cigarette smokers, cocaine users, symptomatic aneurysms, >10mm, and located in posterior circulation

Reference:
Ontario Health Technology Advisory Committee. Coil Embolization for Intracranial Aneurysms. January 2006.

Subependymal Giant Cell Astrocytoma

Fig 1&2: Axial and coronal MR images (contrast enhanced T1WI) show an enhancing mass in the left caudothalamic groove in a patient with known tuberous sclerosis. Given the size and enhancement on this initial scan, a concern of SGCA should be raised.

Subependymal giant cell astrocytoma (SGCA)

• 1 in 10 individuals with TSC
• Arises from subependymal nodules
• Can result in ventricular obstruction
  
• It is recommended by the National Tuberous Sclerosis Association that brain imaging obtainend at every 1-3 years in children, up to the age of 21 years, to detect giant cell astrocytoma

Imaging Appearances That May Suggest SGCA

• Serial growth (best imaging predictor)
• Hydrocephalus
  
• Contrast enhancement
• Size >1 cm

Reference:
Goh S, Butler W, Thiele EA. Subependymal giant cell tumors in tuberous sclerosis complex. Neurology 2004;63:1457-1461.

Chronic Pulmonary Embolism

Fig. 1&2: Axial CT image shows a partial thrombus (stars) in the main and proximal left pulmonary artery that forms an obtuse angle with the vessel wall. There is enlarged pulmonary artery and bronchial collaterals (arrows).

Facts

• Some pulmonary emboli do not resolve and form endothelialized fibrosis of pulmonary vascular bed, thought to be due to disturbance in thrombus resolution
• Results: pulmonary HT, cor pulmonale, bronchial hypertrophy

Risks

• Multiple episodes of PE
• Younger age
• Larger perfusion defect
• Idiopathic cause of PE

CT signs

• Complete thrombus with small vascular diameter
• Partial crescent-shaped, eccentric thrombus
• Calcified thrombus
• Web, band
• Pulmonary hypertension
• Collaterals from bronchial arteries
• Mosaic attenuation of the lungs

Reference:
Castaner E, et al. CT diagnosis of chronic pulmonary thromboembolism. Radiographics 2009;29:31-50.

Commoditization of Radiology

In the latest issue of the Journal of the American College of Radiology (JACR), Giles Boland MD took on a hot topic of 'commoditization' of radiology specialty.

What is Commoditization?

• The word 'commoditization' is actually derived from a noun 'commodity'. Commodity means "a raw material or primary argricultural product that can be bought and sold, such as copper or coffee" , according to an Apple's Dictionary.
• According to Wikipedia: Commodity is "anything for which there is demand but that is supplied without qualitative differentiation across a market".
• "A product that is the same no matter who produces it."
• Examples: oil, rice, sugar, salt, ethanol, gold, silver

What If Radiology Is a Commodity...

• No referring physicians care whether who interprets the examination.
• There is no differentiation among different providers.
• Price of radiology services are determined as a function of the market: fluctuating and universal, changing based on supply and demand.
• Etc.

What Leads Radiology To Become a Commodity?

• Electronic imaging network, PACS
• Teleradiology
• Individual radiologist

What Radiologists Can Do To Prevent It?

Well, you can't stop the pace of technology (electronic networking, PACS), and business (teleradiology), but you can do more as an individual radiologist:

1. Be a part of clinical care team: active participation in an interdepartmental conference, active engagement in patient care (phone call or personal discussion)
2. Build an effective relationship with referring physicians
3. Guide technologists to obtain appropriate images of high quality
4. Devise disease-specific imaging protocols
5. Participate in an effort to reduce radiation dose
6. Actively involve in reduction of unnecessary imaging and update imaging appropriateness criteria
7. Educate younger, newcomer radiology residents, fellows, medical students on best imaging practice
8. Be subspecialized, or at least having an area of expertise in one or two specific modalities or clinical specialties, to keep up with referring physicians.

Reference:

Boland GWL. Teleradiology for auction: the radiologist commoditized and how to prevent it. JACR 2009 (DOI 10.1016/j.jacr.2008.10.006).