DW-MRI of liver lesions: can a single ADC-value represent the entire lesion?

Predictive Value of MRI with Serum Lectin-Reactive Alpha-Fetoprotein for Liver Cancer Recurrence after Percutaneous Radiofrequency Ablation

Objective

To explore the predictive value of magnetic resonance imaging (MRI) with serum lectin-reactive alpha-fetoprotein (AFP-L3) for liver cancer recurrence after percutaneous radiofrequency ablation (RFA).

Methods

This study included 94 liver cancer patients admitted for RFA treatment and 82 healthy subjects. MRI was performed to record the apparent diffusion coefficient (ADC). The serum concentrations of AFP-L3 were quantified in all participants. The correlation of the AFP-L3 serum level and ADC value with clinical efficacy following RFA was analyzed. Moreover, the prognostic factors affecting liver cancer recurrence were analyzed, as well as the predictive effect of the ADC value and AFP-L3 on liver cancer recurrence.

Results

The serum AFP-L3 level was higher in liver cancer patients than the healthy controls with a lower ADC value. Besides, the patients with tumor residuals had lower ADC values and higher serum AFP-L3 levels than those with complete ablated tumor. The combined detection of the ADC value and serum AFP-L3 level had a sensitivity of 87.50% and a specificity of 87.18% for diagnosing complete ablation after RFA treatment. The number of tumor nodules, tumor diameter, AFP, AFP-L3, and the presence of liver cirrhosis are all independent risk factors for liver cancer recurrence within one year. Meanwhile, the combined detection of the ADC value and serum AFP-L3 level had a good predictive effect on liver cancer recurrence with the sensitivity of 92.86% and a specificity of 69.62%.

Conclusion

The ADC values combined with serum AFP-L3 detection had good predictive effects on complete ablation and recurrence of liver cancer after RFA treatment.

Evaluation of ADCratio on liver MRI diffusion to discriminate benign versus malignant solid liver lesions

PURPOSE

The aim of this project is to investigate the usefulness of the absolute liver lesion ADC value and ratio of Apparent diffusion coefficient (ADC) values of a liver lesion and liver parenchyma to discriminate between a benign and malignant lesion.

METHODS

Liver MRI scans performed between January 2009 and June 2015 were retrospectively analysed. Scans were performed on either a 1.5 T or 3 T MRI unit. The type of liver lesion (benign or malignant) was determined by its radiological appearance, histology result and clinical management. Lesions with undetermined diagnosis or MRI studies degraded by artifacts were excluded. Liver cysts were also excluded from the analysis. ADC value of a lesion and liver parenchyma was measured and ADC_ratio was calculated. The values were analysed using independent samples t-test Results:Data set contained 39 benign lesions and 36 malignant lesions. Mean ADC value for benign lesions was 1678, and the mean value for malignant lesions was 1097 with a statistically significant difference of p < 0.001. All lesions with ADC value below 955 were malignant, while all lesions with ADC value above 1880 were benign. ADC value of 1260 was identified as the best available cut-off value for differentiating benign and malignant lesions, achieving sensitivity of 92%, specificity of 80% and an overall accuracy of 89%. The mean lesion to liver ADC_ratio for benign lesions was 1.3467 and for malignant lesions was 0.9038 with a statistically significant difference of p < 0.001. All lesions with ADC_ratio measuring <0.9 were malignant while lesions with ADC_ratio>1.5 were benign. ADC_ratio of 1.1 was identified statistically as the best available cut-off value for differentiating benign from malignant lesions, with sensitivity of 82%, specificity of 86% and an overall accuracy of 92%.

CONCLUSION

Our dataset indicates that lesion to background liver ADC_ratio is superior in discriminating between benign and malignant focal lesions compared to absolute ADC values of the hepatic lesions.

Assessment of different mathematical models for diffusion-weighted imaging as quantitative biomarkers for differentiating benign from malignant solid hepatic lesions

To quantitatively compare the monoexponential, biexponential, and stretched‐exponential diffusion‐weighted imaging (DWI) models in differentiating benign from malignant solid hepatic lesions. The institutional review board approved this retrospective study and waived the informed consent requirement. A total of 188 patients with 288 hepatic lesions included 202 malignant lesions and 86 benign lesions were assessed (confirmed by pathology or clinical follow‐up for 6 months). All patients underwent hepatic 3.0‐T MRI, including multi‐b DWI that used 12 b values. The ADC, D_p, D_t, perfusion fraction (f_p), α, and DDC values for normal liver, benign liver lesions, and malignant liver lesions were calculated. Independent sample t tests were used for comparisons. The diagnostic performance of the parameters was evaluated using ROC analysis. The AUC value for each model was also calculated. The value of D_p was significantly lower in benign lesions than in normal hepatic parenchyma while others were significantly higher (P < .001). Whereas Values of D_t and α in malignant hepatic lesions were significantly higher than in normal hepatic parenchyma (P < .001), and the D_p value was significantly lower (P < .001). Values of ADC, f_p, DDC, and α for malignant hepatic lesions were significantly lower than those for benign hepatic lesions (P < .001). ROC analysis showed that the diagnostic value of the biexponential model of normal hepatic parenchyma vs benign hepatic lesions and normal hepatic parenchyma vs malignant hepatic lesions was high (0.946 and 0.876, respectively). In the differential diagnosis of benign and malignant hepatic lesions, DDC had the highest AUC value (0.819). The biexponential and stretched‐exponential DWI may provide additional information and improve the differential diagnosis of benign and malignant hepatic lesions compared with the monoexponential DWI.