MRI evaluation of bone marrow changes in the diabetic foot: a practical approach.

One of the most important roles of magnetic resonance (MR) in imaging of the diabetic foot is to differentiate between the common and often comorbid pathologies that present with abnormal bone marrow signal. The primary diagnostic challenges in this setting are to distinguish osteomyelitis from reactive bone marrow edema, neuroarthropathy from osteomyelitis, and the sterile from the superinfected neuropathic joint. Whereas both osteomyelitis and reactive marrow edema share increased T2 signal, osteomyelitis is confirmed by T1 hypointensity in the bone marrow and reactive edema demonstrates isolated T2 signal hyperintensity. In distinguishing osteomyelitis from neuroarthropathy, a localized or contiguously spreading forefoot focus of abnormal bone marrow away from the subchondral surface and adjacent to a skin ulcer, cellulitis, abscess, or sinus tract would be indicative of osteomyelitis. A midfoot, subchondral, periarticular, or polyarticular distribution of findings in the absence of a contiguous focus of skin disruption would strongly support neuroarthropathy. Parameters that have been successfully correlated with acute infection superimposed on neuroarthropathy include diffuse bone marrow signal abnormality, progressive subarticular enhancement, loss of subchondral cysts, and the presence of the MRI "ghost sign."

Subretinal hemorrhage masquerading as a hemorrhagic choroidal detachment in a case of nonaccidental trauma.

Retinal hemorrhages are the most commonly reported ocular findings in nonaccidental trauma in children. Other reported ocular findings include perimacular folds, traumatic retinoschisis, choroidal hemorrhages, and retinal detachments. We report the clinical and pathologic findings in a case of a 10-month-old boy who sustained nonaccidental trauma and whose clinical presentation was characteristic of a hemorrhagic choroidal detachment. Postmortem examination revealed a large subretinal hemorrhage, with no evidence of choroidal hemorrhage.

Duane syndrome in association with 48,XXYY karyotype.

Duane syndrome is an ocular motility disorder consisting of deficient horizontal eye movements, eyelid retraction, palpebral fissure narrowing, and abnormal vertical eye movements. It occurs in 1%-5% of patients with strabismus and has also been reported in several syndromes and chromosome abnormalities. Although most cases are sporadic, autosomal-dominant inheritance is seen in up to 10% of cases. Recently, Duane syndrome has been reported to occur in the setting of chromosomal duplication. The 48,XXYY syndrome is a rare syndrome involving duplication of the sex chromosomes. Ocular abnormalities are not typical of this condition. We report the first case of Duane syndrome presenting in an 8-month-old boy with XXYY syndrome. This case lends further support to the association of chromosomal duplication and Duane syndrome.