Differential diagnosis of cerebral hemispheric pathology: multimodal approach.

This article gives a comprehensive review and illustrations of the imaging features of various pathological conditions and clinical syndromes associated with cerebral hemispheric involvement. The various conditions are described and defined to provide a basis for the differential diagnostics. The hypotheses relating to the pathology of the various syndromes are discussed with special emphasis on excitotoxic mechanisms for explaining the subsequent cerebral hemiatrophy.

The "thickened" ligamentum flavum: is it buckling or enlargement?

BACKGROUND AND PURPOSE: Thickening of the LF is ascribed to buckling due to DSN. Uncertainty exists as to whether this can occur without DSN. Our primary hypothesis was that facet degenerative changes alone, independent of DSN, can thicken the LF. Our secondary hypothesis was that inflammatory changes surrounding degenerative facet joints may incite thickening. MATERIALS AND METHODS: Fifty-two patients were divided into 1 of 3 groups: group 1 (normal lumbar spine, n = 21), group 2 (LF thickening and FH with normal height of the L4-5 disk, n = 18), and group 3 (LF thickening and FH with decreased height of the L4-5 disk, n = 13). LF thickness measured on axial T1WI at the midpoint of the LF length was compared with that in group 1. Facet joints were evaluated for spurring, joint fluid, and cortical irregularity, indicating facet degeneration. Enhancement of the facet joints and LF thickening were also evaluated (n = 2). The Student t test was used to compare groups. RESULTS: Normal LF thickness (group 1) was 3.1 mm, whereas LF thickness averaged 4.9 mm in group 2 and 5.3 mm in group 3 (both P < .001). Patients with asymmetric LF thickness showed greater LF thickness on the side with greater FH. There was more LF enhancement on the side with greater facet degenerative disease. CONCLUSIONS: LF thickening can be secondary to facet degenerative changes, independent of DSN. Inflammatory changes may be an inciting factor for LF thickening.

The rare third branchial cleft cyst.

Third branchial cleft cysts (BCCs) are rare entities that represent abnormal persistence of the branchial apparatus. On CT examination, these cysts appear as homogeneous low-attenuation masses with well-circumscribed margins; on MR imaging, they demonstrate variable signal intensity on T1-weighted images and are hyperintense relative to muscle on T2-weighted images. Definitive treatment is surgical excision. We present a case of a third BCC and describe its diagnosis and treatment.

Lateral pterygoid muscle rhabdomyolysis.

We report a case of rhabdomyolysis due to acetaminophen overdose involving the lateral pterygoid muscles bilaterally, in addition to the other muscles of the abdomen and pelvis. To the best of our knowledge, involvement of the head and neck muscles by rhabdomyolysis has not been reported previously. The isolated involvement of the lateral pterygoid muscles may be due to the presence of the surrounding pterygoid venous plexus. It is important to be aware of the imaging characteristics of rhabdomyolysis and to consider the possibility of involvement of head and neck muscles to aid in early diagnosis and avoid misinterpretation of the imaging findings.