T. Kumazaki

Safety of gadolinium contrast agent in hemodialysis patients

PURPOSE We evaluated the safety of a gadolinium (Gd) contrast agent in hemodialysis patients. MATERIAL AND METHODS Seventy hemodialysis patients underwent contrast-enhanced MR examination. After the examination, the patients were hemodialyzed on a usual schedule, i.e., 3 times per week at 4 h each session. The hemodialysis was performed on the same day in 16 patients, the next day in 34, 2 days later in 14 and 3 days later in 6 patients. Serum Gd concentrations before and after the first to fourth hemodialysis sessions were analyzed in 11 patients. Cardiovascular, cutaneous, respiratory, psycho-neurological and digestive side effects were evaluated in all patients. Changes in liver and kidney functions, blood counts, and electrolytes were also checked. RESULTS AND CONCLUSION Neither side effects nor blood changes were noted in any of the patients. Average excretory rates were 78.2%, 95.6%, 98.7% and 99.5% in the first to fourth hemodialysis sessions, respectively. These results suggest that Gd contrast agents can be used in hemodialysis patients if hemodialysis is carried out promptly after the examination.

Delayed hyper-enhancement of myocardium in hypertrophic cardiomyopathy with asymmetrical septal hypertrophy: comparison with global and regional cardiac MR imaging appearances.

To evaluate the relationship between delayed hyper‐enhancement of the myocardium and global and regional cardiac abnormalities in hypertrophic cardiomyopathy (HCM) with asymmetrical septal hypertrophy using magnetic resonance (MR) imaging.

Detection and characterization of focal liver lesions using superparamagnetic iron oxide-enhanced magnetic resonance imaging: comparison between ferumoxides-enhanced T1-weighted imaging and delayed-phase gadolinium-enhanced T1-weighted imaging

AbstractBackground: Double contrast magnetic resonance (MR) imaging using superparamagnetic iron oxide (SPIO) and gadolinium (Gd) is performed to detect and characterize focal liver lesions. However, this technique is a costly and lengthy process. The purpose of this study was to determine the usefulness of SPIO-enhanced MR imaging including SPIO-enhanced T1-weighted imaging in diagnosing focal liver lesions. Methods: Eighty-four focal liver lesions were examined with a 1.5-T MR unit. Transverse precontrast T1- and T2-weighted images and SPIO (ferumoxides)-enhanced T1- and T2-weighted images were obtained, followed by Gd-enhanced T1-weighted imaging. The Gd set (i.e., precontrast T1- and T2-weighted and delayed-phase gadolinium-enhanced T1-weighted images) and ferumoxides set (i.e., precontrast T1- and ferumoxides-enhanced T1- and T2-weighted images) were reviewed by two independent readers. Results: More lesions were detected from the ferumoxides set than from the Gd set. Ferumoxides-enhanced T1-weighted imaging showed enhancement patterns of the lesions similar to those of delayed-phase Gd-enhanced T1-weighted imaging. The diagnoses of hepatic metastasis and cyst by the ferumoxides set were similar to those by the Gd set. However, a dynamic study may be inevitable for the diagnosis of hepatocellular carcinoma and hemangioma. Conclusion: The ferumoxides set was useful for the detection of focal hepatic lesions. Ferumoxides-enhanced T1-weighted imaging may replace delayed-phase gadolinium-enhanced T1-weighted imaging in the diagnosis of hepatic metastasis and cysts.

Aberrant left gastric vein directly draining into left portal venous system. A case report.

A 66-year-old man with early gastric cancer and liver cirrhosis was diagnosed by preoperative angiography as having an aberrant left gastric vein communicating directly with the left lateral portal vein system. This communication was confirmed during operation for the gastric cancer. Our report is the first of an aberrant left gastric vein showing direct communication with the left portal vein system.

Aberrant Right Gastric Vein Draining Directly into the Quadrate Lobe of the Liver A Case Report

Angiography and arterial angio-CT in a 21-year-old man with idiopathic portal hypertension revealed an aberrant right gastric vein communicating directly with the quadrate lobe of the liver. This is the first report of a radiologically confirmed case of an aberrant right gastric vein with a unique area of distribution in the liver parenchyma.

Contrast-enhanced T1-weighted black-blood fast spin-echo MR imaging of the brain. Technique for suppression of enhancing venous signal.

Purpose: Contrast-enhanced T1-weighted black-blood fast spin-echo MR imaging (BB-FSE) was performed to suppress enhancing venous signal and flow artifacts in the brain without sacrificing the T1-weighted imaging contrast. Material and Methods: Twenty-five MR imaging sections (17 transverse and 8 coronal images) in 15 patients with various brain diseases were obtained by contrast-enhanced T1-weighted SE and BB-FSE images. Results: In contrast-enhanced T1-weighted BB-FSE images, venous signal was significantly less and T1-weighted contrast of the brain was more evident. No differences in flow artifacts were found between the two imaging techniques. The interobserver agreements were good for the venous signal and flow artifacts using both techniques. Conclusion: Contrast-enhanced T1-weighted BB-FSE imaging reduced the venous signal in the brain with maintaining T1-weighted contrast. This novel MR technique can be used when the suppression of enhancing venous signal is expected to improve the depiction of enhancing lesions in the brain.

Aberrant Right Gastric Vein Draining Directly into the Quadrate Lobe of the Liver

Angiography and arterial angio-CT in a 21-year-old man with idiopathic portal hypertension revealed an aberrant right gastric vein communicating directly with the quadrate lobe of the liver. This is the first report of a radiologically confirmed case of an aberrant right gastric vein with a unique area of distribution in the liver parenchyma.

Evaluation of the Exposure Dose Reduction in Full-Field Digital Mammography System

We evaluated image quality characteristic of full-field digital mammography (Senographe 2000D; GEMS, CR-AL film;FUJIFILM) system in comparison with screen film mammography (Senographe DMR+;GEMS, Min-R 2000/Min-R 2000; Kodak) system and investigated the possibility of exposure dose reduction in FFDM system. To evaluate each systems image quality characteristics, we measured characteristic curve, modulation transfer function (MTF)value, and wiener spectrum (W.S) value, image qualities and observer performance by RMI-156 phantom and CDMAM phantom were also evaluated in accordance with the change of exposure dose. W.S value of FFDM become equal to that of SFM system in the amount of 60% exposure dose. The phantom studies reveled that the observer performance of FFDM system was also superior to that of SFM system. Those results indicated the possibility of exposure dose reduction in FFDM.

Clinical Evaluation of CR Mammography in Comparison with Full-Field Digital Mammography

To prospectively evaluate the clinical diagnostic equivalence of a new CR mammography (CRM) system and a full-field digital mammography (FFDM) system using hard copy images. 103 patients were imaged with FFDM and 91 patients were imaged with CRM. Sensitivity, specificity, positive predictive value (PPV), and ROC analysis were used to compare the differences in observer performance between the two systems. The number of the readers was five. The overall sensitivity of the FFDM system was 76.8% versus 70.3% for the CRM system. The overall specificity for the FFDM system was 86.9% versus 91.5% for the CRM system. The overall PPV for the FFDM system was 67.2% versus 85.5% for the CRM system. The average area under the ROC- curve (A(z)) for the FFDM system was 0.905 versus 0.907 for the CRM system.