Online ISSN: 2515-8260

Efficacy of Diffusion Weighted Imaging (DWI) and Apparent Diffusion Coefficient (ADC) in Characterizing Hepatic Lesions and Differentiating Regenerating Nodules from HCC in the Case of Liver Cirrhosis -An Observational Study

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Manish Nair Mohanan Nair1*, Lekshmy Remanan2, Sandhya Kuniyil3

Abstract

Purpose: Evaluating the efficacy of DWI and Apparent Diffusion coefficient (ADC) value in characterizing hepatic lesions and in differentiating regenerating nodules from HCC in the background of liver cirrhosis. Methods: In this observational study 40 patients with malignant liver lesions and 19 patients with benign liver lesions were included. Out of these 59 patients, 35 patients had a history of cirrhosis. DWI was used to characterize these lesions. Hepatic lesions in patients with cirrhosis were categorized into hepatocellular carcinomas (HCC) and regenerative nodule. The different ADC values obtained in these proven cases were used to derive a cut off ADC value to differentiate malignant from benign lesions. All these patients were referred to the department of radio diagnosis at Amrita Institute of Medical Science and research centre, Kochi, Kerala, India. Data were collected from June 2019 to June 2021 prospectively. Results: In the current study we could derive an ADC value which can be effectively applied to categorize lesions into malignant and benign. However there was no significant difference in ADC values between malignant lesions with considerable overlap in ADC values of HCC and other malignant lesion. Therefore, application of ADC value to differentiate between malignant lesions was not useful. ADC value was insufficient to further sub-characterize the malignant lesions into HCC and other malignant lesions even in the background of cirrhosis. However, it is useful in differentiating regenerating nodules from HCC in the case of liver cirrhosis. ADC values of different malignant lesions were nearly same with a decimal difference and hence a cut off to differentiate between these malignant lesions were not possible. Similarly, there was no significant difference between the ADC values of benign solid lesions by which we could subcategorize them. In this study ADC cutoff value of 1.45x10-3 mm2 /s was used to differentiate benign from malignant lesions. Conclusion: This study showed that application of the derived ADC cut off value of 1.45 was effective to differentiate malignant from benign lesions and it was also useful in differentiating regenerating nodules from HCC in the background of cirrhosis. It was not applicable to further subcategorize the malignant and benign lesions as obtained by histopathology. With the help of DWI, existing gold standard involving liver biopsy and its complications can be avoided in patients having a risk of contrast allergy and severe renal failure

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