Characterization of focal liver lesions using quantitative techniques: comparison of apparent diffusion coefficient values and T2 relaxation times

Abstract

ObjectivesTo compare the efficacy of two quantitative methods for discrimination between benign and malignant focal liver lesions (FLLs): apparent diffusion coefficient (ADC) values and T2 relaxation times.MethodsSeventy-three patients with 215 confirmed FLLs (115 benign, 100 malignant) underwent 1.5-T MRI with respiratory-triggered single-shot SE DWI (b = 50, 400, 800) and dual-echo T2TSE (TR = 3,000 ms; TE1 = 84 ms; TE2 = 228 ms). ADC values and T2 relaxation times of FLLs were calculated. Sensitivity, specificity and accuracy of both techniques in diagnosing malignancy were assessed.ResultsThe mean ADC value of malignant tumours (1.07 × 10−3 mm2/s) was significantly lower (P < 0.05) than that of benign lesions (1.86 × 10−3 mm2/s ); however, with the use of the optimal cut-off value of 1.25 × 10−3 mm2/s, 20 false positive (FP) and 20 false negative (FN) diagnoses of malignancy were noted, generating 79 % sensitivity, 82.6 % specificity and 80.9 % accuracy. The mean T2 relaxation time of malignant tumours (64.4 ms) was significantly lower (P < 0.05) than that of benign lesions (476.1 ms). At the threshold of 107 ms 22 FP and 1 FN diagnoses were noted; the sensitivity was 99 %, specificity 80.9 % and accuracy 89.3 %.ConclusionsQuantitative analysis of T2 relaxation times yielded significantly higher sensitivity and accuracy in diagnosing malignant liver tumour than ADC values.Key Points• Diffusion-weighted magnetic resonance imaging is increasingly used for liver lesions.• But ADC values demonstrated only moderate accuracy for differentiation of liver lesions.• T2 relaxation times yielded higher accuracy in diagnosing malignant liver tumours.• Both ADC and T2 values overlapped between focal nodular hyperplasia and malignant lesions.• Nevertheless T2 liver mapping could be valuable for evaluating focal liver lesions.

Intrahepatic cholangiocarcinomas mimicking other lesions

“…Although considerable overlap exists between benign lesions and malignant tumors, and DWI cannot differentiate between different malignant tumors [33][34][35][36], restricted diffusion seen in an indeterminate lesion may strengthen the suspicion of a possible malignancy and help exclude perfusional anomalies, as was the case in our cohort, and may alert the radiologist of a need for continued followup of the lesions or for recommending biopsy. When the target sign is present on DWI, the diagnosis of cholangiocarcinoma should be entertained even if other findings are indeterminate [19].…”

Added Value of Diffusion-Weighted Acquisitions in MRI of the Abdomen and Pelvis

“…Furthermore, solid lesions that have low cellularity (e.g., mucinous rectal carcinomas) may not show restricted diffusion. Lack of restricted diffusion in these circumstances may lead to false-negative results [25, 26]. Additionally, both benign and malignant solid lesions can show restricted diffusion.…”

Improved differentiation between hepatic hemangioma and metastases on diffusion-weighted MRI by measurement of standard deviation of apparent diffusion coefficient

“…In particular, liver hemangiomata represent one of the more difficult, yet common, lesions to consistently diagnose by DW-MR alone [5,6]. To date, studies assessing quantitative diffusion metrics have usually assessed the mean apparent diffusion coefficient (mADC) value of liver lesions in an attempt to distinguish benign from malignant etiologies.…”