Intestinal Ascariasis

Author: Santip Srisuwan, M.D.

Axial CT image shows multiple tubular filling defects (arrows) within the opacified lumen of the small bowel. Note contrast filling within the filling defects.

Facts:

• Most common helminthic infection (worldwide prevalence 25%)
• Usually asymptomatic.
• Possible symptoms are colicky abdominal pain in adults and growth retardation/intussusception/volvulus in children

Imaging

• X-ray: usually normal but may present as bowel obstruction (partial or complete), or soft tissue masses
• US: hypo echoic curvilinear tubular structures with well-defined echogenic walls and curling movement of the worm during the exam
• CT: long, thin tubular structure coiled within the small bowel, outlined by oral contrast materials

References:

1. Hommeyer SC, Hamill GS, Johnson JA. CT diagnosis of intestinal ascariosis. Abdom Imaging 1995;20:315-316.

2. Rodrigues EJ, Gama MA, Ornstein SM, et al. Ascariasis causing small bowel volvulus. Radiographics 2003;23:1291-3.

3. Villamizar E, Mendez M, Bonilla E, et al. Ascaris lumbricoides infestation as a cause of intestinal obstruction in children: experience with 87 cases. J Pediatr Surg 1996;3:201-4.

4. Hendi JM, Horton KM, Fishman EK. Ascariasis infection of the colon: MDCT evaluation. Emerg Radiol 2006;12:180-1.

5. Bude RO, Bowerman RA. Case 20: Biliary ascariasis. Radiology 2000;214:844-7.

6. Hershkovitz D, Wasserberg N. Large bowel obstruction due to Ascaris lumbricoides. IMAJ 2004;6:115-116.

Triquetral Fracture

A lateral wrist radiograph shows a small bone fragment (arrow) dorsum to the wrist with overlying soft tissue swelling.

Facts:

• Second most common carpal bone fracture
• Two main types: dorsal chip fracture and body fracture
• Dorsal chip fracture (like in our case ) believed to be due to forceful impingement of the triquetrum during wrist hyperextension
• Body fracture frequently associated with perilunate dislocation (direct blow)
• Pain and swelling localized at the dorsum of the wrist where triquetrum is located
• Complication: motor branch of ulnar nerve injury

Imaging

• Chip fracture best seen on lateral radiograph with hand in flexion
• Body fracture best seen on AP and oblique radiographs
• Fractures are possibly underreported. CT can help in suspected cases.

Reference:

Simon RR, Koenigsknecht SJ. Emergency orthopedics: the extremities, 2001.

Pneumothorax on Ultrasound

M-mode ultrasound images of the lungs (right and left) show a normal "lung sliding" on the right side "Right" and absence of it on the left side "Left".

Facts:

• Ultrasound can be performed to diagnose pneumothorax with high accuracy
• Normal "lung sliding" is seen when pleura moves against the chest wall during respiration. The movement is easily seen on real-time imaging and can be captured on M-mode ultrasound
• M-mode US shows normal lung sliding as a "seashore sign", in which the motion of pleura/lung produces sand-like granular appearance on the image. The non-mobile chest wall shows several uninterrupted band or "sea"
• Some diseases may produce "loss of lung sliding", most notably pneumothorax

Pneumothorax on US

• Absence of lung sliding shown on real-time imaging
• On M-mode as "barcode sign" or "stratosphere sign" (see above image labeled "left")
• More specific sign is the "lung point sign"

Our case: left pneumothorax (confirmed with radiography)

Reference:

Lichtenstein DA, Menu Y. A bedside ultrasound sign ruling out pneumothorax in the critically ill. Chest 1995; 108:1345-48.

Calcification in Lung Nodule

A spot chest radiographic view of the left lower lung zone (with a nipple marker) shows a 1-cm nodule (arrow) in the lung base just medial to the nipple marker.

Non-contrast CT confirms the presence of a nodule in the left lower lobe (arrow) that contains a central calcification.

Lung Nodule Calcification

• Up to 6% of lung cancer have calcification. Therefore, calcium in a nodule does not exclude possibility of lung cancer
• Suspected malignant nodule if calcium is.... eccentric, amorphous or it involves only a small portion of the nodule
• Benign: central (>10% of cross-sectional area of nodule), diffuse and laminated calcification
• Nodules that are nonsolid or partly solid are more often malignant

Our case: benign nodule, likely a granuloma.

Reference:

Hodler J, von Schulthess GK, Zollikofer ChL. Diseases of the Heart, Chest & Breast 2011-2014. Springer-Verlag Italia 2011.

Sternoclavicular Rheumatoid Arthritis

Axial CT images of the sternoclavicular joints show erosion, indistinct cortical margins of the joints, which are quite symmetric.

Facts:

• Sternoclavicular (SC) joint is diarthrodial articulation between axial and appendicular skeleton, which is subject to same disease process that occur in other joints (degenerative arthritis, rheumatoid arthritis, infection and subluxation. Degenerative arthritis is the most common).
• Up to 30% of patients with rheumatoid arthritis have changes in SC joints (a part of polyarticular involvement) but radiographic findings are often unremarkable.

Imaging Finding

• Synovitis
• Bone marrow edema and enhancement of subcortical bone (after IV contrast)Er
• Erosion and indistinct cortical margins
• Think infection if: unilateral, history of IVDU and immunocompromised states

References:

1. Restrepo CS, Martinez S, Lemos DF, et al. Imaging appearance of the sternum and sternoclavicular joints. Radiographics 2009; 29:839-859.

2. Berry DJ, Steinmann SP. Adult Reconstruction, 2007.