Diffusion-weighted MRI and optimal b-value for characterization of liver lesions.

BACKGROUND: Diffusion-weighted imaging (DWI) is commonly used to distinguish between benign and malignant liver lesions. However, different b-values are recommended. PURPOSE: To determine the most suitable b-value in DWI for differentiation of benign and malignant liver lesions. MATERIAL AND METHODS: A total of 124 lesions in 89 consecutive patients (43 men, 46 women; age, mean ± standard deviation, 58 ± 14 years) with a pathological or radiological diagnosis of malignant or benign focal liver lesions after magnetic resonance imaging (MRI) were included in this study. Routine abdominal MRI and DWI were performed using seven b-values (0, 50, 200, 400, 600, 800, 1000 s/mm(2)). Lesions were analyzed for benignity/malignity using apparent diffusion coefficient (ADC) values with 10 b-value combinations and by measuring the lesion/normal parenchyma ADC ratio. RESULTS: Mean ADC values were significantly different between malignant and benign lesions for all b-value combinations (P=0.000). The best b-value combination was 0 and 800 (Az=0.935). Using lower b-values such as 0 and 50 together with higher b-values ≥ 600 s/mm(2) was beneficial (Az=0.928 and 0.927). Mean ADC values were approximately 13% (1-15%) higher in total when b=0 and b=50 s/mm(2) were included in multiple b-value combinations. CONCLUSION: In DWI, we recommend the use of b-values of 0 and 800 s/mm(2) as two b-values, or b=0, 50, 600, 800, and 1000 s/mm(2) as multiple b-values for distinguishing between benign and malignant liver lesions. Mean ADC value is 13% higher in total by additional use of b=0 and b=50 s/mm(2) in multiple b-value combinations.

Impotence due to external iliac steal syndrome: treatment with percutaneous transluminal angioplasty and stent placement.

We report a case of erectile dysfunction caused by external iliac artery occlusion, associated with pelvic steal syndrome; bilateral internal iliac arteries were patent. The patient stated that he had experienced erectile dysfunction at similar times along with claudication, but he did not mention it before angiography. He expressed that the erectile dysfunction did not last long and that he felt completely okay after the interventional procedure, in addition to his claudication. Successful treatment of the occlusion, by percutaneous transluminal angioplasty and stent implantation, helped resolve erectile dysfunction completely and treat the steal syndrome.