RESUMEN
BACKGROUND: Hip abduction can cause avascular necrosis (AVN) of the femoral head in infants. OBJECTIVE: To compare the US perfusion pattern of femoral head cartilage in neutral position with that in different degrees and duration of abduction, testing the venous congestion theory of post-abduction ischemia. MATERIALS AND METHODS: In 20 neonates, the Doppler flow characteristics of the posterosuperior (PS) branch of the femoral head cartilage feeding vessels were evaluated in neutral and at 30 degrees, 45 degrees, and 60 degrees abduction. In three neonates the leg was held in 45-degree abduction and flow was assessed at 5, 10, and 15 min. RESULTS: Male/female ratio was 11/9 with a mean age of 1.86 +/- 0.7 weeks. The peak systolic velocities (PSV) declined in all three degrees of abduction. After 15 min of 45-degree abduction, the mean PSV declined and showed an absent or reversed diastolic component and undetectable venous return. No perfusion was detected at 60-degree abduction. CONCLUSION: Abduction-induced femoral head ischemia is biphasic and degree- and duration-dependent. In phase I there is arterial hypoperfusion and in phase II there is venous congestion. A new pathogeneses for femoral head ischemia is offered.
Asunto(s)
Cartílago Articular/irrigación sanguínea , Cartílago Articular/diagnóstico por imagen , Necrosis de la Cabeza Femoral/diagnóstico por imagen , Cabeza Femoral/irrigación sanguínea , Cabeza Femoral/diagnóstico por imagen , Hiperemia/diagnóstico por imagen , Isquemia/diagnóstico por imagen , Ultrasonografía Doppler en Color , Velocidad del Flujo Sanguíneo , Femenino , Necrosis de la Cabeza Femoral/etiología , Humanos , Hiperemia/etiología , Recién Nacido , Isquemia/etiología , Masculino , PosturaRESUMEN
PURPOSE: Physiologic uptake of 2-[(18)F]-fluoro-2-deoxy-D: -glucose (FDG) by bowel can confound positron emission tomography/computed tomography (PET/CT) assessment for abdominal pathology, particularly within the bowel itself. We wished to determine if oral administration of the antimotility agent, Lomotil (5 mg diphenoxylate hydrochloride/0.05 mg atropine sulfate; G.D. Searle and Company, a division of Pfizer), prior to PET/CT scanning would reduce physiologic uptake of FDG by the small bowel and colon (lower gastrointestinal [GI] tract). PROCEDURES: Patients undergoing PET/CT scans for lymphoma were enrolled in a prospective, randomized, double-blinded study and received either 10 mL water (control group) or 10 mL Lomotil (experimental group) orally 30-60 min prior to scanning. Scans were reviewed independently by two blinded experienced readers and scored for the degree of FDG activity in the lower GI tract relative to liver activity. RESULTS: The administration of Lomotil prior to PET/CT scanning did not reduce physiologic FDG activity in the small bowel and colon. In contrast, increased radiotracer uptake by the lower GI tract was observed in the Lomotil group compared to the control group. CONCLUSIONS: Pretreatment with Lomotil prior to PET/CT scanning confers no benefit toward the reduction of physiologic FDG uptake by the small bowel and colon.