Positron emission tomography and central neurotransmitter systems in movement disorders

Summary— This article discusses the anatomical and neurochemical structure of the basal ganglia and reviews the Positron Emission Tomographic (PET) ligands available for investigating these pathways. We discuss how clinical PET studies have improved our understanding of the neurochemical changes underlying principal movement disorders.     

Oxygen tension in human tumors: in vivo mapping using CT-guided probes

The role of oxygen in tumor response to therapy has been studied for several decades. We describe a technique that allows in vivo measurement of oxygen in tumors using computed tomography to guide probes. In the evaluation of 16 tumors, oxygen tensions were found to be substantially lower than surrounding tissue and varied nonrandomly. This technique has allowed construction of detailed tumor oxygen level maps.     

Osteochondritis dissecans: analysis of mechanical stability with radiography, scintigraphy, and MR imaging

Twenty-one joints with stable (n = 9) or loose (n = 12) osteochondritis dissecans (OCD) lesions were examined in 15 subjects with plain radiography, three-phase bone scintigraphy, and magnetic resonance (MR) imaging. The lesion size and the thickness of the sclerotic margin as measured on plain radiographs were good parameters for predicting loosening. However, bone scintigraphy was more sensitive and specific in determining the mechanical stability of OCD lesions. MR imaging permitted direct visualization of loosening and fragment displacement; the latter permits differentiation of in situ loosening from a grossly unstable lesion. The noninvasive nature of bone scintigraphy and MR imaging makes them potentially preferable diagnostic modalities to arthrography for evaluating the mechanical status of OCD lesions.     

Spectrum of medulloblastomas demonstrated by computed tomography

Twenty-two patients with medulloblastomas were evaluated by computed tomography. Pretreatment evaluation in 13 patients has shown the various presentations of the tumor. Eighteen of the patients have had post-therapy computed tomographic studies. Computed tomography is sensitive in detecting residual and locally recurrent tumor as well as tumor seeding by cereborspinal fluid pathways. Computed tomography has proved to be valuable in patient management and in evaluating the effectiveness of various forms of treatment. The present group of medulloblastomas is compared to other pediatric posterior fossa tumors and differential diagnoses are discussed.