Kiyoshi Ishii

Error analysis of table look-up method for cerebral blood flow measurement by123I-IMP brain SPECT: Comparison with conventional microsphere model method

While N-isopropyl-p-[123I]iodoamphetamine (IMP) is commonly used as a flow tracer, significant clearance from the brain causes underestimation of CBF as compared with true CBF when conventional microsphere model analysis is applied. We previously reported a simple “table lookup” method for CBF measurement using IMP taking into account this clearance effect. The method is based on a two-compartment model, the K1 (corresponding to CBF) and k2 constants being obtained from a table from the ratio of the 1st SPECT (40 min) to the 2nd SPECT (180 min) counts. Arterial input data used were obtained by one point blood sampling 10 min after IMP infusion against the standard input function. In the present study, this approach was compared with conventional microsphere model analysis. For 30 subjects, the latter method entailed 8 min continuous arterial blood sampling after IMP infusion and the use of SPECT data at the end of this period, calibrated by a count ratio of 8 min/40 min planar images of whole brains. A good correlation was observed between the two methods (r = 0.88), but an overestimation of table look-up method CBF as compared with microsphere model CBF was observed contrary to theoretical predictions. Limitations in the estimation of SPECT data at 8 min, obtained with SPECT data at 40 min for calibration of the count ratio of 8 min/40 min whole brain planar images, might be responsible for this.

Unruptured carotid-duplicated middle cerebral artery aneurysm: case report.

We demonstrate the first case with unruptured carotid-duplicated middle cerebral artery (IC-Dup MCA) aneurysm combined with ruptured opposite carotid aneurysm. Eleven IC-Dup MCA aneurysm reported until now had all ruptured. It is noteworthy that 8 patients of the 11 were Japanese.

Error analysis of autoradiography method for measurement of cerebral blood flow by123I-IMP brain SPECT: A comparison study with table look-up method and microsphere model method

N-isopropyl-p-[123I]iodoamphetamine (IMP) has been commonly used as a cerebral blood flow tracer, but, significant clearance of IMP from the brain to the blood causes underestimation of cerebral blood flow (CBF) as compared with true CBF when the conventional microsphere model method is applied. Previously, we reported an “Autoradiography method” (ARG method) for measuring CBF by using IMP in which this clearance effect was corrected. This method was based on a two-compartment model (influx: K1 efflux: k2, K1/k2 = distribution volume of IMP (Vd)), the K1 (corresponding to CBF) being obtained from the table which showed a correlation between CBF and the brain counts of SPECT scan with a constant Vd value. Arterial input data used were obtained by one point blood sampling 10 min after IMP infusion against the standard input function. In the present study, the ARG method was compared with the table look-up method (TLU method) and the conventional microsphere model method (MS method) for 30 subjects. When the Vd value in the ARG method was assumed to be 50 ml/ml, CBF values obtained by the ARG method were correlated well with those obtained by the TLU method (Y= 1.04X−2.5;X: TLU,Y: ARG, r = 0.97) and those obtained by the MS method (Y = 0.82X + 12.1;X: ARG,Y: MS, r = 0.84). But, when the Vd value was assumed to be more or less than 50 ml/ml, ARG method CBF were under-or overestimated compared with the TLU method. This indicated that the ARG method could be a reliable method for CBF measurement if the Vd was determined properly. CBF values obtained by the MS method were actually 13.2% higher than those obtained by the ARG method against previous studies. As reasons for this, errors in the effects of gray-white matter mixture in the ARG method and in estimation of the SPECT brain counts at 8 min in the MS method were considered.

Cerebral perfusion changes in traumatic diffuse brain injury; IMP SPECT studies

Diffuse brain injury (DBI) is characterized by axonal degeneration and neuronal damage which cause diffuse brain atrophy. We have investigated the time course of abnormalities in cerebral perfusion distribution in cases of DBI by using Iodine-123-IMP SPECT, and the relationship to the appearance of diffuse brain atrophy. SPECT scans were performed on eight patients with diffuse brain injury due to closed cranial trauma in acute and chronic stages. All patients showed abnormalities in cerebral perfusion with decreases in perfusion, even in non-depicted regions on MRI, and the affected areas varied throughout the period of observation. Diffuse brain atrophy appeared in all patients. In some patients, diffuse brain atrophy was observed at or just after the time when the maximum number of lesions on SPECT were seen. The abnormalities in cerebral perfusion in cases of DBI might therefore be related to axonal degeneration and neuronal damage which causes diffuse brain atrophy.

Rearranged limonoids from Harrisonia brownii

Abstract A new limonoid, brownin C, was isolated from the bark of Harrisonia brownii, and a new limonoid, brownin G, from the wood of the same plant. Their structures were determined by spectral techniques and X-ray crystal structure analysis.

Brownins A and B: Novel rearranged limonoids from Harrisonia brownii

Abstract Two highly rearranged limonoids of a novel skeletal type, brownins A (1) and B (2), have been isolated from the bark of Harrisonia brownii (Simaroubaceae). Their structures were determined by spectral data and X-ray diffraction analysis.

Javanicinosides D-H, quassinoid glucosides from Picrasma javanica

Abstract From Picrasma javanica , five new quassinoid glucosides, javanicinosides D-H, together with known quassinoids, neoquassin and picrasin A and triterpenoids, hispidol A and lanosta-7,24-dien-3-one were isolated. The structures have been determined by spectral analysis and chemical evidence.

Brownins D and E: New limonoids from Harrisonia brownii

Abstract Two new limonoids, brownin D ( 1 ) and E ( 2 ), were isolated from the bark of Harrisonia brownii (Simaroubaceae). Their relative stereostructures were established by specific methods and X-ray diffraction analysis of 1 .

Symptom changes caused by movement of a calcified lateral ventricular meningioma: Case report

BACKGROUND Large calcified psammomatous meningioma in the left lateral ventricle with a long silent interval of 16 years was presented. The symptoms varied by its moving not enlargement, which was described by sequential images of the brain computer tomography. Combined approaches of transcallosal and transinferior temporal sulcus routes were superior to prevent injury of the speech center in the dominant hemisphere.