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Hajime Sakuma

Publications and source records attributed to Hajime Sakuma.

25 records · Page 2Linked to original sources
PubMed2003

Quantitative assessment of diffusion abnormalities in benign and malignant vertebral compression fractures by line scan diffusion-weighted imaging.

OBJECTIVE: Acute vertebral collapse is common, and it is sometimes difficult to determine whether the cause is benign or malignant. Recently, diffusion-weighted imaging has been reported to be useful for differentiating the two types. The purpose of this study was to evaluate diffusion abnormalities quantitatively in benign and malignant compression fractures using line scan diffusion-weighted imaging. SUBJECTS AND METHODS. Line scan diffusion-weighted imaging was prospectively performed in 17 patients with 20 acute vertebral compression fractures caused by osteoporosis or trauma, in 12 patients with 16 vertebral compression fractures caused by malignant tumors, and in 35 patients with 47 metastatic vertebrae without collapse. Images were obtained at b values of 5 and 1,000 sec/mm(2). The apparent diffusion coefficient (ADC) was measured in vertebral compression fractures and metastatic vertebrae without collapse. RESULTS: The ADC (mean +/- SD) was 1.21 +/- 0.17 x 10(-3) mm(2)/sec in benign compression fractures, 0.92 +/- 0.20 x 10(-3) mm(2)/sec in malignant compression fractures, and 0.83 +/- 0.17 x 10(-3) mm(2)/sec in metastatic vertebral lesions without collapse. The ADC was significantly higher in benign compression fractures than in malignant compression fractures (p < 0.01), although the two types showed considerable overlap. CONCLUSION: Although the quantitative assessment of vertebral diffusion provides additional information concerning compressed vertebrae, the benign and malignant compression fracture ADC values overlap considerably. Therefore, even a quantitative vertebral diffusion assessment may not always permit a clear distinction between benign and malignant compression fractures.

Aged↗
PubMed2002

Midterm results of stent-graft repair of acute and chronic aortic dissection with descending tear: the complication-specific approach.

BACKGROUND: Endovascular stent-graft placement for the treatment of patients with aortic dissection is emerging as an attractive alternative to conventional cardiac operations. However, there has been no report of longer-term follow-up. The purpose of this study is to describe our midterm results with endovascular stent-graft repair for the treatment of patients with aortic dissections. METHODS: Thirty-eight patients with aortic dissections with descending tears were treated with endovascular stent-grafting. Ten patients had acute type A, 14 patients had acute type B, and 14 patients had chronic type B dissection. Stent grafts fabricated from expanded polytetrafluoroethylene-covered Z stents were placed to close entry tears in all patients through the delivery systems introduced from the femoral or the iliac arteries. RESULTS: Two patients with complicated acute type B dissection, who would have required surgical intervention, died within 30 days of the procedure, although no other patients died within the same period. There were no late deaths during the mean follow-up period of 27 months. Early and late complication rates were 33% and 36%, respectively, in patients with acute dissection, whereas rates were 4% and 0% (P <.05 vs patients with acute dissection) in patients with chronic dissection. CONCLUSIONS: Entry closure with endovascular stent-graft placement may be a safe and effective method for the treatment of patients with aortic dissection. It could be an alternative to conventional surgical intervention in selected patients with chronic dissection. However, strict patient selection and close follow-up seem mandatory in patients with acute dissection receiving Z stent-based stent-grafts. Stent-graft repair should be delayed for acute type B dissection without complications.

Acute Disease↗
PubMed2002

[Optimal use of contrast medium in contrast enhanced MR imaging of the heart].

With the recent development of fast MR imaging techniques, the diagnostic value of contrast enhanced MR imaging of the heart has been substantially improved. Since no tissue-specific contrast medium is available for clinical cardiac MR imaging at this point, both the early and late dynamics of extracellular MR contrast medium should be carefully evaluated for assessing the multiple aspects of cardiac function, including myocardial blood flow, myocardial, viability, and left ventricular function. Myocardial blood flow can be assessed by monitoring the first-pass passage of MR contrast medium. Quantitative assessments of arterial input function and output function in the regional myocardium can provide more accurate detection of altered myocardial blood flow in patients with coronary artery disease. Excellent contrast between infarcted myocardium and normal tissue can be obtained with delayed contrast enhanced MR imaging. Myocardial infarction, including small subendocardial infarction and chronic scar, is demonstrated as an area of "hyperenhancement" on delayed enhanced MR images, while the signal from normal myocardium is nearly null. This review paper describes the optimal dose and injection rate of MR contrast material for functional cardiac MR imaging studies. In addition, practical suggestions for obtaining good cardiac MR images and interpreting contrast enhanced MR images are given and are explained in detail.

Contrast Media↗
PubMedDate not supplied

A case of inverted left atrial appendage mimicking a tumor.

We report a rare case of an inverted left atrial appendage without prior cardiac surgery. A left atrial mass was incidentally found during routine echocardiography in a 19-year-old man with mitral valve prolapse. Echocardiography revealed a hyperechoic mass in the left atrium, and a neoplastic lesion could not be excluded. On magnetic resonance imaging (MRI), this mass consisted of fat tissue that showed continuation to epicardial fat, indicating an inverted left atrial appendage mimicking a tumor in the left atrium. When a mass in the left atrium is observed on echocardiography, there are several differential diagnoses, including thrombus, vegetation, and intra-atrial neoplasms such as myxomas. Recently, several studies reported cases with inverted left atrial appendages mimicking tumors in patients after cardiac operations. We present a case of inverted left atrial appendage without any prior cardiac surgery. Cardiac MRI was highly useful to obtain the final diagnosis of inverted left atrial appendage.

Adipose Tissue↗