T Mamiya — Page 6 | Search PubMed

PubMedDate not supplied

The optimum Butterworth-Wiener filter for I-123 IMP brain SPECT.

The optimum Butterworth-Wiener filter (BWF) for the preprocessing of N-isopropyl-p-[I-123]-iodoamphetamine (I-123 IMP) SPECT was determined by a simulation experiment. Sixty-four images of the brain phantom containing 14.8 MBq of I-123 IMP were collected with a gamma camera equipped with a slant hole collimator during a 360-degree rotation. The images were processed with 27 BWFs of different shapes, followed by SPECT image reconstruction and visual comparison. The optimum BWF had a cutoff frequency of 0.25/pixel, FWHM of four pixels, and constant of 0.05. The image quality was greatly affected by the cutoff frequency of BWF used for preprocessing.

Brain↗

PubMedDate not supplied

Measurement of cerebral blood flow with two-dimensional cine phase-contrast mR imaging: evaluation of normal subjects and patients with vertigo.

PURPOSE: The purpose of this study was to determine whether or not the vertebral flow of patients with vertigo and normal brain magnetic resonance (MR) images was decreased in comparison with normal controls. MATERIALS AND METHODS: Cerebral blood flow (CBF) was quantitatively measured by a two-dimensional phase contrast cine MR imaging technique in 24 normal controls (mean age, 38.6 years; range, 12-70) and 23 patients (mean age, 53.7 years; range, 19-76) with a 1.5 Tesla MR imaging unit. RESULTS: Inter- and intraobserver variation in blood flow measurements was small (r = 0.970, standard error of the estimate [SEE] = 2.9 ml, n = 80; r = 0.963, SEE = 4.6 ml, n = 40, respectively). In the normal group, mean summed vertebral flow (171 ml/min, SD = 40.6) was significantly less than mean summed carotid flow (523 ml/min, SD = 111). Right vertebral flow (80.2 ml/min, SD = 30.5) was less than left vertebral flow (91.2 ml/min, SD = 38.2), but the difference was not statistically significant (p < 0.05). In the 23 patients, although the summed vertebral flows of two patients (63.3, 88.8 ml/min) were significantly less than that of the normal group, mean summed vertebral flow (165 ml/min, SD = 59.1) showed no significant difference from that of the normal group (p < 0.05). CONCLUSIONS: In this study, the majority of patients had normal CBF. This method is clinically useful for estimating CBF.

Adolescent↗

PubMedDate not supplied

Delayed imaging of Tc-99m-DTPA-HSA SPECT in subacute cerebral infarction.

Cerebral blood volume measurement by Tc-99m-DTPA-HSA SPECT was performed in a patient with subacute cerebral infarction to evaluate compensatory vasodilatation. Additional delayed imaging revealed focal increased radioactivity that was not found on the early images, indicating leakage of radioactive agents due to blood-brain barrier breakdown. Delayed SPECT may be helpful to detect areas unsuitable for estimating regional blood volume.

Acute Disease↗