Deep Brain Nuclei T1 Shortening after Gadobenate Dimeglumine in Children: Influence of Radiation and Chemotherapy.

BACKGROUND AND PURPOSE: Intrinsic T1-hyperintense signal has recently been reported in the deep gray nuclei on brain MR imaging after multiple doses of gadolinium-based contrast agents. Most reports have included adult patients and excluded those undergoing radiation or chemotherapy. We investigated whether T1 shortening is also observed in children and tried to determine whether radiochemotherapy is a risk factor for this phenomenon. MATERIALS AND METHODS: In this single-center retrospective study, we reviewed clinical charts and images of all patients 18 years of age or younger with ≥4 gadobenate dimeglumine-enhanced MRIs for 6 years. Seventy-six children (mean age, 9.3 years; 60 unconfounded by treatment, 16 with radiochemotherapy) met the selection criteria (>4 MR imaging examinations; mean, 8). T1 signal intensity ratios for the dentate to pons and globus pallidus to thalamus were calculated and correlated with number of injections, time interval, and therapy. RESULTS: Among the 60 children without radiochemotherapy, only 2 had elevated T1 signal intensity ratios (n = 20 and 16 injections). Twelve of the 16 children with radiochemotherapy showed elevated signal intensity ratios. Statistical analysis demonstrated a significant signal intensity ratio change for the number of injections (P < .001) and amount of gadolinium (P = .008), but not for the interscan time interval (P = .35). There was a significant difference in the average signal intensity ratio change between those with and without radiochemotherapy (P < .001). Chart review revealed no new neurologic deficits in any patients, related to their underlying conditions and prior surgeries. CONCLUSIONS: Compared with published adult series, children show a similar pattern of T1 hyperintense signal changes of the dentate and globus pallidus after multiple gadobenate dimeglumine injections. The T1 signal changes in children may have a later onset but are accelerated by radiochemotherapy.

Orbital wall infarction in sickle cell disease: MR evaluation.

Orbital wall infarction in a patient with sickle cell disease can present with periorbital swelling and subperiosteal collection and thus can mimic infection on CT. However, MR not only provides excellent morphologic information but, by characterizing the nature of the collection as containing blood, and by identifying bone marrow abnormality, can lead to the diagnosis of orbital wall infarction.

Isolated extranodal intracranial sinus histiocytosis in a 5-year-old boy. Case report.

Sinus histiocytosis with massive lymphadenopathy was first described in 1969 by Rosai and Dorfman. The typical clinical characteristics of this disease include painless cervical lymphadenopathy, fever, and weight loss. The condition can present with an extranodal mass in about 25% of patients, and isolated masses without lymph node involvement occur rarely. The authors describe a 5-year-old boy with cavernous sinus syndrome due to an isolated extranodal form of sinus histiocytosis with massive lymphadenopathy in the temporal fossa. Several cases of this disease involving the central nervous system are reviewed. The histopathological and magnetic resonance imaging characteristics are discussed.