Diffusion‐weighted imaging of the liver: Optimizing b value for the detection and characterization of benign and malignant hepatic lesions

Abstract

Purpose:To determine the optimal b values required for diffusion-weighted (DW) imaging of the liver in the detection and characterization of benign and malignant hepatic lesions. Materials and Methods:MR images obtained in 76 patients including 28 malignant hepatic lesions (21 hepatocellular carcinomas and 7 metastases) and 27 benign lesions (12 hemangiomas and 15 cysts) were reviewed. DWecho planner images (EPIs; b values with100, 200, 400, and 800 s/mm 2 ) were reviewed solely first, and then with T2-weighted EPIs (b ϭ 0 s/mm 2 ).Results: Sensitivity for malignant lesions (74%) was highest on DW-EPIs with b value of 100 s/mm 2 and T2-weighted EPIs combined (P Ͻ 0.05), and sensitivity for benign lesions (87%) was highest on DW-EPIs with b value of 800 s/mm 2 and T2-weighted EPIs (P Ͻ 0.05). Specificities were comparably high for all sequences. The Az values for malignant lesions were 0.94, 0.90, 0.87, and 0.89, and those for benign lesions were 0.91, 0.89, 0.87, and 0.94 on DW-EPIs with b values of 100, 200, 400, and 800 and T2-weighted EPIs combined, respectively. Hepatic cysts were clearly distinguished with the cutoff ADC value of 2.5 ϫ10 Ϫ3 mm 2 /s using a b value of 400 s/mm 2 or greater.Conclusion: DW-EPIs with middle b values were not required in the detection and characterization of benign and malignant hepatic lesions.

Diffusion-Weighted MR Imaging of the Benign Hepatic Focal Lesions

“…Mean ADC values of cyst and haemangioma were significantly higher than other benign hepatic focal lesions. This coincides with other studies [18] [20] [24].…”

“…[21]. But, it does not correlate with other studies [22]- [24]. The difference may be due to using different b value, different technique either breath-hold or respiratory triggered, or different pathological types of haemangiomas.…”

Diffusion weighted MRI for detecting and monitoring cancer: a review of current applications in body imaging

“…DWI is able to differentiate between benign and malignant focal hepatic lesions, in many cases because of the higher ADC of benign lesions compared with malignant lesions (56)(57)(58). This finding is thought to be the result of cellular membranes impeding the mobility of water molecules.…”

Using magnetic resonance imaging and spectroscopy in cancer diagnostics and monitoring

“…21 Similarly, ADC can be used to separate malignant and benign hepatic lesions. 22 In addition, diffusion MRI has shown great potential for separating benign from malignant head and neck tumors and thereby guiding biopsing. 23 Recent technical advancements in body MR have indicated that DWI may provide valuable information for lymph node staging, 24 which has recently been possible in situ only by radionucleotide techniques, such as PET.…”