PubMed Health⌕ Search

Biomedical subjects

R Nakashima

Publications and source records attributed to R Nakashima.

41 records · Page 3Linked to original sources
PubMedDate not supplied

Usefulness of turbo-FLASH dynamic MR imaging of dissecting aneurysms of the thoracic aorta.

PURPOSE: We attempted to determine whether Turbo-FLASH dynamic magnetic resonance imaging is clinically useful for the diagnosis of dissecting aneurysm of the thoracic aorta by differentiating slow flow from thrombus in the false lumen. METHODS: Magnetic resonance imaging (MRI) was performed in ten patients using three different pulse sequences (spin echo, cine and turbo-FLASH dynamic MRI). The three imaging techniques were compared for their ability to demonstrate anatomical and hemodynamic abnormalities by visual assessment. RESULTS: In all patients with thrombus in the false lumen, the thrombus was accurately differentiated from slow flow on contrast enhanced turbo-FLASH dynamic MRI, but only with difficulty on spin echo and cine MRI. Dynamic MRI was also useful for the evaluation of flow dynamics in the false lumen. CONCLUSION: Turbo-FLASH dynamic MRI is recommended for patients with dissecting aneurysm of the thoracic aorta, not definitely diagnosed by spin echo and cine MRI.

Aged↗
PubMedDate not supplied

Measurement of effective renal plasma flow (ERPF) with 123I-orthoiodohippurate (I-123-OIH).

We evaluated the necessity of attenuation correction for calculating effective renal plasma flow (ERPF) using I-123-orthoiodohippurate (OIH), an agent introduced recently to replace I-131-OIH. From a kidney phantom experiment, the attenuation coefficient (mu) for I-123-OIH in the human body was determined as 0.1262 cm-1. I-123-OIH renal scintigraphy was performed in 23 patients with urinary diseases with blood sampling for calculation of ERPF by Tauxe's method. Calculated renal uptake, with or without attenuation correction, was compared with ERPF determined by Tauxe's method. There was good correlation between renal uptake without attenuation correction and ERPF obtained by Tauxe's method (r = 0.737), while much better correlation was found between attenuation-corrected renal uptake and ERPF calculated by Tauxe's method (r = 0.816). In conclusion, attenuation correction for renal uptake is an important technique for estimating ERPF using I-123-OIH renal scintigraphy.

Adolescent↗
PubMedDate not supplied

Functional evaluation of transplanted kidneys by Gd-DTPA enhanced turbo FLASH MR imaging.

We evaluated the usefulness of dynamic turbo FLASH MR imaging in the differential diagnosis of complications after renal transplantation in 17 patients (10 from living relatives and 7 from cadavers). Coronal turbo FLASH dynamic images were obtained every 5 sec for 5 min after an intravenous bolus injection of Gd-DTPA. Corticomedullary differentiation (CMD) on spin echo coronal T1-weighted images and MR renogram patterns of the renal cortex and medulla were obtained for quantitative analysis of the Gd-DTPA-enhanced dynamic turbo-FLASH images. The signal intensity ratio of the medulla to cortex after Gd-DTPA enhancement was compared among four groups: normal (n = 9), acute tubular necrosis (ATN) or cyclosporine A (CyA) tubulopathy (n = 6), acute rejection (AR) in the living related donor kidney (n = 4), and AR in the cadaveric kidney (n = 5). Although loss of CMD was seen in severe renal dysfunction in the transplanted kidneys, there was considerable overlap among the four groups. On dynamic study, there was significant differences in the signal intensity ratio of the medulla to cortex between normally functioning kidneys or ATN/CyA tubulopathy and AR (p < 0.01). In patients with severe renal dysfunction, the arterial cortical peak was indistinct. In conclusion, MR renograms obtained from dynamic turbo FLASH MR imaging played a significant role in evaluating dysfunction of the renal transplant.

Acute Disease↗