Michimasa Matsuo

Proton two-dimensional chemical shift imaging for evaluation of prostate cancer: External surface coil vs. endorectal surface coil

To compare the diagnostic ability of proton magnetic resonance spectroscopy (MRS) using an external surface coil with that using an endorectal surface coil in patients with prostate cancer.

An MRI study of the myelination pattern in West syndrome

Using magnetic resonance imaging (MRI), we studied the myelination of the brains of 8 patients with West syndrome. All cases were symptomatic, 2 having severe asphyxia, 1 lissencephaly, 1 Leigh encephalopathy, 2 tuberous sclerosis, 1 multiple anomalies and 1 microcephaly. Myelination of the pons, cerebellum, thalamus, internal capsules, optic radiation, centrum semiovale and cerebral white matter was separately assessed. The 2 cases with tuberous sclerosis exhibited normal myelination patterns, although asymmetry of the cerebral white matter was noted. These cases had a moderate degree of mental retardation and persistent seizures. The other 6 cases exhibited a marked delay of myelination throughout the central nervous system except for the midbrain. These cases had severe psychomotor retardation and persistent seizures. Although the difference in the outcome may simply reflect the different etiological disorders, these results suggest that the myelination pattern is related to the psychomotor retardation but not to the severity of the seizures in West syndrome. Atrophy of the corpus callosum developed during ACTH therapy and disappeared after the therapy. It was thus suggested that the callosal atrophy caused by the ACTH therapy was reversible.

Distinction of hepatic vein from portal vein by MR imaging

Fast magnetic resonance (MR) imaging techniques are assuming importance in imaging of the abdomen in part due to their ability to produce images during breath-holding, which ensures high spatial resolution and no respiratory motion artifacts. One problem with rapid scanning of the liver, shared with other MR techniques, is confusion between portal and hepatic veins due to similarity in signal intensity. The fast low angle shot (FLASH) technique (flip angle 40 degrees, repetition time 28 ms, and echo time 16 ms) produces high signal in both venous systems. To remedy the problem we incorporated presaturation pulses applied across the portal and mesenteric veins to the FLASH technique; this induced a decrease in signal in the portal venous system and facilitated their differentiation from hepatic veins. Moreover, in one patient an intraportal tumor thrombus not detected on the standard FLASH technique was rendered visible by presaturation. Although the presaturation pulses in the present series were confined to the sagittal plane, the technique should be applicable in any plane as dictated by the anatomy and direction of blood flow. We anticipate wide use of combined presaturation and rapid scanning techniques.

A Supporting System for Getting Tomograms and Screening with a Computerized 3D Brain Atlas and a Knowledge Database

We introduce a system which includes a 3D atlas of a human central nervous system, a knowledge database which has correspondences between patient’s symptoms and damaged nerves, and a display tool which has various graphical display methods to show 3D structure of damaged nerves and its adjoining organs. 3D atlas is composed of two MRI images and a labeled image whose labels stand for motor nerves and brain matters. The knowledge database includes 66 if-then rules. If a user uses this system, he will be able to acquire appropriate sectional images and the corresponding atlas data needful for screening images, diagnosing patients and planning a therapy.