[Progress in MR imaging: differential diagnosis of infectious and inflammatory diseases with MR imaging].

MR imaging is useful for diagnosis of infectious and inflammatory diseases. Diffusion weighted images (DWI) and fluid-attenuated inversion recovery (FLAIR) images revealed hyperintense signal changes in the anterior striata and cortices in patients with Creutzfeldt-Jakob disease, which were characteristic. In patients with nonherpetic and non-paraneoplastic acute limbic encephalitis, DWI and FLAIR images showed hyperintense changes in the hippocampi, amygdales, cingulate gyri, and occasionally claustrum, but not in the anterior and lateral temporal cortices, which were often involved in herpes simplex encephalitis. In ventriculitis, DWI and FLAIR images showed high signal intensity changes with niveau formation in the lateral ventricle, which indicated the presence of pus in the ventricle. In Japanese encephalitis, T2-weighted images showed high signal intensity changes in the thalami and substantia nigra, which were most often involved by Japanese encephalitis. In idiopathic cranial hypertrophic pachymeningitis, thallium-201 SPECT showed a remarkable accumulation in the abnormal dura matter. Furthermore, the abnormal uptake of thallium-201 returned to normal after treatment with corticosteroid. Thallium-201 SEPCT was useful for the evaluation of disease activity in patients with hypertrophic cranial pachymeningitis.