Purpose: To evaluate the effect of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) on T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) for the diagnosis of hepatocellular carcinoma (HCC).
Materials and Methods:The phantom signal intensity was measured. We also evaluated 72 patients including 30 patients with HCC. T2WI and DWI were obtained before and then 4 and 20 min after injecting the contrast medium. The signal to noise ratio (SNR), contrast to noise ratio (CNR), and apparent diffusion coefficient (ADC) were calculated in the tumor and liver parenchyma.
Results:The phantom signal intensity increased on T2WI at a concentration of contrast medium less than 0.2 mmol/L but decreased when the concentration exceeded 0.4 mmol/L. SNR of the liver parenchyma on T2WI was significantly different between before and 4 min after injecting the contrast medium, while there were no significant differences between before and 4 and 20 min after injection. On T2WI, SNR, and CNR of HCC showed no significant differences at any time. SNR, CNR, and ADC of the liver parenchyma and tumor on DWI also showed no significant differences at any time.
Conclusion:It is acceptable to perform T2WI and DWI after injection of Gd-EOB-DTPA for the diagnosis of HCC.
We evaluated the quality of dynamic magnetic resonance (MR) imaging of the temporomandibular joint (TMJ) in 20 normal volunteers with 40 TMJs. To conˆrm TMJ, we obtained static proton density weighted images (PDWI) before performing dynamic MR imaging with true-fast imaging in a steady-state precession (true-FISP) sequence. Four sequences of theˆrst 10 volunteers were examined to determine the optimal sequence. The 4 sequences included the integrated parallel acquisition technique (iPAT) and W or fat saturation technique. The optimal sequence was then determined and performed in all 20 volunteers. The quality of imaging was evaluated, especially with respect to the conspicuity of the articular disk, mandibular condyle, articular eminence and lateral pterygoid muscle. One of 3 conˆdence levels was assigned for this evaluation. Neither iPAT nor fat saturation obtained the best quality imaging. Detection rates in the 20 volunteers were 83z for the articular disk, 95z for the mandibular condyle, 96z for the articular eminence and 7.5z for the lateral pterygoid muscle.We recommend dynamic MR imaging of the TMJ with the true-FISP sequence using neither iPAT nor fat saturation. Nevertheless, dynamic MR imaging was inferior to static imaging in detecting the articular disk and still requires improvement.
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