Biomedical subjects

Aya Abe

Publications and source records attributed to Aya Abe.

5 recordsLinked to original sources

PubMed2005

Identification of the segmental artery feeding the anterior spinal artery: correlation between helical CT and angiography.

PURPOSE: We investigated whether identification of the segmental artery feeding the anterior spinal artery (ASA) is possible by single-slice helical CT. MATERIAL AND METHODS: Enhanced CT and angiography were performed in 14 patients with retroperitoneal, liver, or bone tumor. A single-slice helical CT scanner with 7 mm collimation and a 1.0 helical pitch was used. Scanning was started 25 to 30 sec after an intravenous injection of 100 ml of contrast medium at a rate of 3.0 ml/sec. RESULTS: We predicted the segmental artery feeding the ASA in all 14 patients using enhanced CT images. In 12 of the 14 patients, the segmental artery feeding the ASA was angiographically identified. In 7 of these 12 patients, the level of the segmental artery feeding the ASA identified on segmental arteriogram was the same level as that predicted by enhanced CT. In the remaining 5 patients, the level of the segmental artery feeding the ASA identified on segmental arteriogram was one level higher or lower than the predicted spinal level. CONCLUSION: We could identify the segmental artery feeding the ASA by detailed examination and interpretation of single-slice helical CT images.

Adult↗

PubMed2003

Performance evaluation of a hand-held, semiconductor (CdZnTe)-based gamma camera.

We have designed and developed a small field of view gamma camera, the eZ SCOPE, based on use of a CdZnTe semiconductor. This device utilises proprietary signal processing technology and an interface to a computer-based imaging system. The purpose of this study was to evaluate the performance of the eZ scope in comparison with currently employed gamma camera technology. The detector is a single wafer of 5-mm-thick CdZnTe that is divided into a 16x16 array (256 pixels). The sensitive area of the detector is a square of dimension 3.2 cm. Two parallel-hole collimators are provided with the system and have a matching (256 hole) pattern to the CdZnTe detector array: a low-energy, high-resolution parallel-hole (LEHR) collimator fabricated of lead and a low-energy, high-sensitivity parallel-hole (LEHS) collimator fabricated of tungsten. Performance measurements and the data analysis were done according to the procedures of the NEMA standard. We also studied the long-term stability of the system with continuous use and variations in ambient temperature. Results were as follows. INTRINSIC ENERGY RESOLUTION: 8.6% FWHM at 141 keV.LINEARITY: There was excellent linearity between the observed photopeaks and the known gamma ray energies for the given isotopes. INTRINSIC SYSTEM UNIFORMITY: For the central field of view, the integral uniformity and the differential uniformity were, respectively, 1.6% and 1.3% with the LEHR collimator and 1.9% and 1.2% with the LEHS collimator. SYSTEM SPATIAL RESOLUTION: The FWHM measurements made at the surface of the collimator were 2.2 mm (LEHR) and 2.9 mm (LEHS).CONTRAST TEST: The average S/N ratios (i.e. counts in the irradiated pixel divided by counts in the surrounding pixels) for the inner ring pixels (8)/outer ring pixels (16) using the LEHS collimator and LEHR collimator were 3.2%/0.2% and 3.7%/0.3%, respectively. COUNT RATE CHARACTERISTICS: We could not determine the maximum count rate and the 20% loss count rate from these data because the plateau was not reached while using the solutions measured. SYSTEM SENSITIVITY: The average acquisitions were 11,052 cpm/MBq (LEHR) and 28,590 cpm/MBq (LEHS). TEMPERATURE DEPENDENCE: The system displayed minimum corresponding shift in cps with temperature changes in the measured temperature range. We designed and developed a semiconductor-based gamma camera using CdZnTe. The basic performance of this camera compares favourably with the existing gamma camera technology that is deployed in the medical field today. The most significant differences include the spatial resolution, sensitivity, high count rate characteristics and energy resolution. We believe that this device will be of value for a number of clinical applications including sentinel node detection and radiopharmaceutical-guided surgery.

Cadmium↗

PubMed2003

Scoring analysis of salivary gland scintigraphy in patients with Sjögren's syndrome.

The purpose of the present study was to evaluate the validity of a scoring system based on excretion rate of salivary gland scintigraphy in patients with Sjögren's syndrome (SjS). Total scintigraphic scores were compared with the results of the Saxon test. One hundred and twenty-four subjects who were clinically diagnosed with SjS and 11 normal ones underwent salivary gland scintigraphy and the Saxon test. In salivary gland scintigraphy, the difference between maximum and minimum counts after stimulation using vitamin C divided by maximum counts was defined as the excretion rate. We then defined a scoring system with 4 grades: severe dysfunction = 3 (excretion rate < 25%), moderate dysfunction = 2 (25% < or = excretion rate < 40%), mild dysfunction = 1 (40% < or = excretion rate < 50%) and normal function = 0 (50% < or = excretion rate). The summation of the total scintigraphic score (0-12) of all 4 salivary glands was used as a semi-quantitative index indicating total salivary gland function, and total scintigraphic scores were compared with the results of the Saxon test. A significant inverse linear correlation (R2 = 0.95) was observed between total scintigraphic scores and mean values of the Saxon test within a range of abnormal scintigraphic scores (> or = 4). The scoring system developed in the present study is a clinically available, objective, and reproducible method for evaluation of salivary gland function in patients with SjS.

Adult↗

PubMedDate not supplied

Congenital absence of the portal vein: clinical and radiologic findings.

Congenital absence of the portal vein (CAPV) is a rare anomaly in which the intestinal and splenic venous drainage bypasses the liver and drains into the systemic veins through various venous shunts. In patients with CAPV, the portosystemic shunting causes disruption of the enterohepatic circulation and leads to various clinical manifestations. CAPV can be diagnosed without invasive techniques. This article illustrates the clinical and radiologic findings (including ultrasound, CT, and MRI) of CAPV.

Adult↗

PubMedDate not supplied

Clinical evaluation of choline measurement by proton MR spectroscopy in patients with malignant tumors.

PURPOSE: To examine whether choline measurement by proton magnetic resonance (MR) spectroscopy in patients with malignant tumors is clinically meaningful in addition to routine MR imaging. MATERIALS AND METHODS: MR spectroscopy and MR imaging were performed in 27 consecutive patients with suspected malignant disease. Malignancy was assessed based on total choline compound levels using proton MR spectroscopy, and the results were compared with MR imaging findings. RESULTS: The sensitivity of MR imaging (84%, 21/25) was not significantly different from that of MR spectroscopy (88%, 22/25) among the 25 actual malignant diseases. Both MR imaging and MR spectroscopy produced two false-negative results. In one case, MR spectroscopy produced a false-negative result, whereas MR imaging produced a true-positive result. In two cases of benign breast disease, MR imaging produced false-positive results. MR spectroscopy produced one true-negative result and one false-positive result. CONCLUSION: Although choline measurement by MR spectroscopy is a useful tool in the evaluation of malignant disease, it should be reserved for patients with suspected malignant disease that cannot be detected by MR imaging, such as those with non-palpable prostate tumor with elevated sPSA levels.

Adult↗