T2-weighted MRI of the upper abdomen: comparison of four fat-suppressed T2-weighted sequences including PROPELLER (BLADE) technique.

RATIONALE AND OBJECTIVES: The aim of this study was to compare four different fat-suppressed T2-weighted sequences with different techniques with regard to image quality and lesion detection in upper abdominal magnetic resonance imaging (MRI) scans. MATERIALS AND METHODS: Thirty-two consecutive patients referred for upper abdominal MRI for the evaluation of various suspected pathologies were included in this study. Different T2-weighted sequences (free-breathing navigator-triggered turbo spin-echo [TSE], free-breathing navigator-triggered TSE with restore pulse (RP), breath-hold TSE with RP, and free-breathing navigator-triggered TSE with RP using the periodically rotated overlapping parallel lines with enhanced reconstruction technique [using BLADE, a Siemens implementation of this technique]) were used on all patients. All images were assessed independently by two radiologists. Assessments of motion artifacts; the edge sharpness of the liver, pancreas, and intrahepatic vessels; depictions of the intrahepatic vessels; and overall image quality were performed qualitatively. Quantitative analysis was performed by calculation of the signal-to-noise ratios for liver tissue and gallbladder as well as contrast-to-noise ratios of liver to spleen. RESULTS: Liver and gallbladder signal-to-noise ratios as well as liver to spleen contrast-to-noise ratios were significantly higher (P < .05) for the BLADE technique compared to all other sequences. In qualitative analysis, the severity of motion artifacts was significantly lower with T2-weighted free-breathing navigator-triggered BLADE sequences compared to other sequences (P < .01). The edge sharpness of the liver, pancreas, and intrahepatic vessels; depictions of the intrahepatic vessels; and overall image quality were significantly better with the BLADE sequence (P < .05). CONCLUSION: The T2-weighted free-breathing navigator-triggered TSE sequence with the BLADE technique is a promising approach for reducing motion artifacts and improving image quality in upper abdominal MRI scans.

Non-breath-hold high b-value diffusion-weighted MRI with parallel imaging technique: apparent diffusion coefficient determination in normal abdominal organs.

PURPOSE: To detect apparent diffusion coefficient (ADC) values in normal abdominal organs using non-breath-hold high b-value diffusion-weighted magnetic resonance imaging (DW-MRI) with a parallel imaging technique. MATERIALS AND METHODS: A total of 50 patients with normal abdominal MRI findings were retrospectively enrolled. DW-MRI was performed with b-factors of 0, 500, and 1000 s/mm(2). Mean ADC measurements were calculated. RESULTS: There were statistically significant differences (P < 0.001) between the ADC values of four liver segments (left lobe lateral segment: 1.77 +/- 0.21 x10(-3) mm(2)/s, left lobe medial segment: 1.59 +/- 0.21 x 10(-3) mm(2)/s, right lobe anterior segment: 1.46 +/- 0.18 x 10(-3) mm(2)/ s, right lobe posterior segment: 1.34 +/- 0.20 x 10(-3) mm(2)/s). The ADC value for the left lobe lateral segment was significantly higher than the values for the other segments. The calculated ADC values for cortex and medulla of kidney were 2.08 +/- 0.22 x 10(-3) mm(2)/ s, 1.94 +/- 0.18 x 10(-3) mm(2)/s, respectively; (P < 0.001), for pancreas tail 1.59 +/- 0.38 x 10(-3) mm(2)/s, for pancreas body 1.68 +/- 0.26 x 10(-3) mm(2)/s, pancreas head 1.65 +/- 0.29 x 10(-3) mm(2)/s, stomach wall 1.84 +/- 0.22 x 10(-3) mm(2)/s, and spleen 1.28 +/- 0.38 x 10(-3) mm(2)/s. CONCLUSION: Knowledge of ADC values for normal abdominal organs will be required during quantitative evaluation of DW-MR images in diseases in accordance with the technique used. We believe that further studies investigating the effect of diseases on normal ADC values are necessary and would be helpful in quantitative DWI.