Preliminary clinical results of proton (1H) imaging of cranial neoplasms: in vivo measurements of T1 and mobile proton density.
Proton nuclear magnetic resonance (NMR) images reflecting T1 relaxation time and approximating proton density were acquired and used to generate T1 rate (1/T1) maps. By region-of-interest selection, measurements of T1 relaxation time were made from discrete volumes of the imaging plane. Such techniques were applied to the study of human cranial neoplasia and associated conditions of differential diagnostic importance (e.g., postoperative changes, radiation necrosis). Inversion-recovery NMR images exhibit a high lesion-detection sensitivity. In all patients, the specificity of NMR imaging is low since all abnormal areas appear as lesions darker than surrounding normal brain, reflecting a decreased proton density, prolonged T1 values, or both. T1 relaxation times are prolonged within neoplastic foci; however, absolute T1 values overlap with those found in other lesions.