Madelung Deformity

Madelung deformity is a growth disturbance of the distal radius caused by focal dysplasia of the physis that results in triangular deformity and medial and volar tilt of the distal radius. Females are more commonly affected than males.

Radiographs will show increased volar bowing of the distal radius, a widened distal radioulnar joint, increased volar tilt of the distal radial articular surface, and an exaggerated ulnar tilt of the distal radius. The carpal bones wedge into the triangular deformity created by the distal radius. In addition, osteophytes may form along the inferior ulnar border of the radius.

Some measurements can be used for the diagnosis of Madelung deformity. When any one of these thresholds is met, a diagnosis of a Madelung deformity can be made.

• Ulnar tilt ≥ 33°: On frontal radiographs, the acute angle between the longitudinal axis of the ulna and a line tangential to the proximal surfaces of the scaphoid and lunate is subtracted from 90.
• Lunate subsidence ≥ 4 mm: On frontal radiographs, the distance between the most proximal point of the lunate and a line perpendicular to the longitudinal axis of the ulna and through its distal articular surface.
• Lunate fossa angle ≥ 40°: On frontal radiographs, the acute angle between the longitudinal axis of the ulna and a line across the lunate fossa of the radius subtracted from 90.
• Palmar carpal displacement ≥ 20 mm: Distance between the longitudinal axis of the ulna and the most palmar point on the surface of the lunate or capitate.

The images show a case where a diagnosis of Madelung deformity was suspected, but only the lunate subsidence was positive.

On MRI, in addition to the radiographic findings, there will be a thickened ligament arising from the ulnar aspect of the distal radius to the lunate, the so-called Vickers ligament.

Differential considerations include:

• Idiopathic Madelung deformity:
• Turner syndrome:
• Dyschondrosteosis: Rare form of mesomelic dysplasia. Characterized by short stature and a Madelung deformity.

References

• Castriota-Scanderbeg A, Dallapiccola B. Chapter 5: Long bones. In Abnormal skeletal phenotypes. Castriota-Scanderbeg A and Dallapiccola B. Springer-Verlag Berlin Heidelberg, 2005. page 313.
• Dawe C, Wynne-Davies R, Fulford GE. Clinical variation in dyschondrosteosis. A report on 13 individuals in 8 families. J Bone Joint Surg Br. 1982;64(3):377-81.
• Dubey A, Fajardo M, Green S, Lee SK. Madelung's deformity: a review. J Hand Surg Eur Vol. 2010 Mar;35(3):174-81.
• Kim HK. Madelung deformity with Vickers ligament. Pediatr Radiol. 2009 Nov;39(11):1251.
• McCarroll HR Jr, James MA, Newmeyer WL 3rd, Manske PR. Madelung's deformity: diagnostic thresholds of radiographic measurements. J Hand Surg Am. 2010 May;35(5):807-12.

Tarsal Tunnel Syndrome

Tarsal tunnel syndrome refers to pain and paresthesia in the plantar aspect of the foot and toes due to nerve entrapment or compression at the level of the posterior tibial nerve or its branches as they pass through the tarsal tunnel.

The flexor retinaculum forms the roof of the tarsal tunnel. Anteriorly, the flexor retinaculum inserts on the anteromedial surface of the medial malleolus and posteriorly, it inserts into the medial tuberosity of the calcaneus. Inferiorly the flexor retinaculum splits to envelop the abductor hallucis muscle.

The floor of the tarsal tunnel is formed by the medial surface of the talus, the sustentaculum tali, and the medial wall of the calcaneus.

The structures of the tarsal tunnel, from anterior to posterior, include the well-known Tom, Dick, and Harry: the tibialis posterior tendon, the flexor digitorum longus tendon, the posterior tibial neurovascular bundle, and the flexor hallucis longus tendon.

Nerve compression can be intrinsic or extrinsic. Intrinsic causes include accessory muscles, ganglion cysts, neurogenic tumors, varicose veins, lipomas, synovial hypertrophy, and scar tissue. Extrinsic causes include foot deformities, hypertrophic and accessory muscles, os trigonum, and excessive pronation in some sports.

References

• Erickson SJ, Quinn SF, Kneeland JB, Smith JW, Johnson JE, Carrera GF, Shereff MJ, Hyde JS, Jesmanowicz A. MR imaging of the tarsal tunnel and related spaces: normal and abnormal findings with anatomic correlation. AJR Am J Roentgenol. 1990 Aug;155(2):323-8.
• Rosenberg ZS, Beltran J, Bencardino JT. From the RSNA Refresher Courses. Radiological Society of North America. MR imaging of the ankle and foot. Radiographics. 2000 Oct;20 Spec No:S153-79.

Pulmonary Langerhans Cell Histiocytosis

Pulmonary Langerhans Cell Histiocytosis is a chronic progressive interstitial lung disease strongly associated with cigarette smoking.

The images here show an upper lobe-predominant process characterized by irregular cysts and nodules in a peribronchiolar distribution. Differential considerations include pulmonary Langerhans cell histiocytosis and lymphangioleiomyomatosis. Emphysema, which shouldn't be a consideration once you note that the cysts have perceptible walls, is included in some differentials.

The classic teaching is that cysts associated with pulmonary Langerhans cell histiocytosis are less uniform in appearance than those associated with lymphangioleiomyomatosis and that Langerhans cell histiocytosis is associated with nodules (especially early in the course of the disease), while lymphangioleiomyomatosis is not. However, more recent (2003) work suggests that there is considerable overlap between the appearance of lymphangioleiomyomatosis and Langerhans cell histiocytosis and that CT can't be reliably used to differentiate the two.

References

• Bonelli FS, Hartman TE, Swensen SJ, Sherrick A. Accuracy of high-resolution CT in diagnosing lung diseases. AJR Am J Roentgenol. 1998 Jun;170(6):1507-12.
• Koyama M, Johkoh T, Honda O, Tsubamoto M, Kozuka T, Tomiyama N, Hamada S, Nakamura H, Akira M, Ichikado K, Fujimoto K, Rikimaru T, Tateishi U, Müller NL. hronic cystic lung disease: diagnostic accuracy of high-resolution CT in 92 patients. AJR Am J Roentgenol. 2003 Mar;180(3):827-35.

Hypoxic-Ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is one of the most common causes of severe neurologic deficit in children and occurs in up to about 10/1,000 live births. HIE is thought to occur due to insufficient cerebral blood flow in combination with decreased oxygen content, which leads to loss of normal cerebral autoregulation and diffuse brain injury.

Different patterns of injury have been described in preterm (< 36 weeks) and term (> 36 week) neonates and based on severity. They include:

• Mild-to-moderate hypotension in preterm infants: The periventricular regions are most affected. MR shows areas of T1 hyperintensity within larger areas of T2 hyperintensity. Periventricular leukomalacia (cavitation and periventricular cyst formation) develops 2 to 6 weeks later. End-stage periventricular leukomalacia refers to progressive necrosis of the periventricular tissue with ex-vacuo enlargement of the ventricles and manifests on cross sectional imaging as ventriculomegaly with irregular margins of the bodies and trigones of the lateral ventricles, loss of periventricular white matter with increased T2 signal, and thinning of the corpus callosum.
• Severe hypotension in preterm infants: The thalami, brainstem, and cerebellum in are most affected due to their high metabolic activity in the immature brain. Ultrasound shows hyperechogenicity, CT shows hypoattenuation, and DWI shows restricted diffusion in these regions. T2 signal is variable.
• Mild-to-moderate hypotension in term infants (shown above): The intervascular watershed zones between the anterior and middle cerebral arteries and between the middle and posterior cerebral arteries and the border zone are affected. The parasagittal cortex and subcortical white matter demonstrate restricted diffusion.
• Severe hypotension in term infants: The lateral thalami, posterior putamina, hippocampi, brainstem, corticospinal tracts, and the sensorimotor cortex are affected. These areas may be hyperechoic on ultrasound and low attenuation on CT. The CT findings may be subtle, with the hypoattenuation of the basal ganglia and thalami manifesting as isoattenuation compared to adjacent white matter. MRI will show abnormal T1 hyperintensity, variable T2 signal, and restricted diffusion in these areas.

References

Chao CP, Zaleski CG, Patton AC. Neonatal hypoxic-ischemic encephalopathy: multimodality imaging findings. Radiographics. 2006 Oct;26 Suppl 1:S159-72.

Endobutton

Endobuttons are used to secure the upper end of a tendon graft, for example in anterior cruciate ligament (top images) or biceps tendon (bottom images) reconstruction. A strip of polyethylene tape (black) is looped around the tendon graft (red) on one end and looped around the center two holes of the Endobutton on the other.

References

• Illinois Sportsmedicine & Orthopaedic Centers (video)
• Smith & Nephew.

Pilomatricoma

Pilomatricomas (pilomatrixoma, calcifying epithelioma of Malherbe) are benign calcifying tumors that arise from skin appendages and are the most common solid cutaneous tumor in patients under 20 years of age. Imaging is generally not used in the evaluation of pilomatricomas, since they are usually superficial, small, and well-circumscribed.

Pilomatricomas are slow-growing subcutaneous tumors that are usually less than 3 cm in diameter. The majority are found in the head and neck, followed by the upper extremities.

Radiographic features of pilomatricomas include regular contours, sharp demarcation from surrounding fat, and a normal overlying skin. Calcifications, when present, are usually speckled or sand-like, but can be large and dense in some cases.

Different ultrasound features have been described. Classically, these are hypoechoic solid nodules that are either fully or partially calcified. However, Pilomatricomas may also have internal fluid signal and a thick-wall.

MRI reveals a mass that is homogeneously isointense to muscle on T1-weighted images. Pilomatricomas can be hypointense to muscle on T2-weighted images with patchy hyperintense areas and striations that radiate from the center toward a hyperintense peripheral rim. Post-contrast images may reveal patchy or reticular enhancement centrally and peripheral enhancement of a connective tissue capsule. A case pilomatricoma without enhancement has also been reported. Peritumoral edema may be seen in some cases.

The case shown here is from a young woman with a longstanding history of a painless, hard bony mass in the left preauricular region. The images are not very exciting, as they are basically blacked out by the calcium, which goes along with the history of a hard bony mass.

References

• De Beuckeleer LH, De Schepper AM, Neetens I. Magnetic resonance imaging of pilomatricoma. Eur Radiol. 1996;6(1):72-5.
• Gustin AF, Lee EY. Pilomatricoma in a pediatric patient. Pediatr Radiol. 2006 Oct;36(10):1113.
• Haller JO, Kassner G, Ostrowitz A, Kottmeler K, Perfschuk LP. Pilomatrixoma (calcifying epithelioma of Malherbe): radiographic features. Radiology. 1977 Apr;123(1):151-3.
• Hoffmann V, Roeren T, Möller P, Heuschen G. MR imaging of a pilomatrixoma. Pediatr Radiol. 1998 Apr;28(4):272.
• Lim HW, Im SA, Lim GY, Park HJ, Lee H, Sung MS, Kang BJ, Kim JY. Pilomatricomas in children: imaging characteristics with pathologic correlation. Pediatr Radiol. 2007 Jun;37(6):549-55.
• Solivetti FM, Elia F, Drusco A, Panetta C, Amantea A, Di Carlo A. Epithelioma of Malherbe: new ultrasound patterns. J Exp Clin Cancer Res. 2010 May 6;29(1):42.

Duodenal Filling Defects

Small

• Lymphoid hyperplasia: Multiple Little (1 mm - 2 mm) filling defects. May be normal in children. May be associated with giardiasis in adults with hypogammaglobunimeia.
• Heterotopic gastric mucosa: Multiple mini (few mm) filling defects clustered in a mosaic pattern.

Large

• Pancreatic rest: Ectopic pancreatic tissue. Smooth (round or lobulated) filling defects 1 cm - 2 cm in diameter. Classical appearance of a central dimple of barium that can be confused with an ulcer. Usually found in the bulb or descending duodenum.
• Brunner gland hyperplasia: Multiple, Big (up to 1 cm or so), rounded filling defects at the bulb that can extend to the descending duodenum. Often produce a cobble stone appearance.

Miscellaneous/Uncommon

• Flexural pseudopolyp: Usually in thin patients. Due to sharp angle between the apex of the duodenal bulb and the descending duodenum, which causes mucosa to bunch up at the apex of the bulb.
• Adenoma: Uncommon. Mucosal polypoid lesions with high potential for malignant degeneration. Usually smaller than 1 cm. Villous adenomas can get larger than 1 cm and are more likely to be found in the periampullary region.
• Mesenchymal tumors: Leiomyoma or lipoma. Most common benign lesions of duodenum. Smooth, submucosal lesions. Ulceration uncommon.
• Kaposi: Multiple polypoid and ulcerated lesions.
• Carcinoid: Typically in the descending duodenum, peripapillary region.
• Choledochocele: Causes extrinsic compression.
• Papillitis: Enlarged major papilla due to inflammation, usually recent passage of a calculus.