To evaluate the role of DW MRI combined with mean ADC values to differentiate between bland and malignant portal vein thrombus.

The study was carried on 25 patients referred to the Department of Radiodiagnosis and Intervention, Alexandria Main University Hospital. They underwent dynamic contrast enhanced MRI liver using 1.5 T Siemens machine and proved to have PVT whether bland or tumoral. We have detected 26 PVT in our 25 patients, due to the presence of concomitant bland and malignant PVT within the same patient.

The 26 PVT were divided into 2 groups: 10 bland and 16 malignant PVT.

The enhancement pattern was used as our reference for sure sign of malignancy. By using ROIs, mean ADC values of bland and malignant PVT were calculated to reach a cut off value.

1. The study showed statistical significance between the mean ADC values of the bland and the malignant PVT which were (1.48 x10-3 mm2/sec ± 0.35 SD) and (0.93 x10-mm2/sec ± 0.13 SD) respectively.
2. A cut off value of (≤1.1 × 10-3 mm2/sec) for mean ADC values of PVT was calculated using ROC curve. It proved to be highly diagnostic of malignancy with area under curve (0. 891), P value (0.001), sensitivity (93.75%), specificity (80%), positive predictive value (88.2%), and negative predictive value (88.9%)
3. Statistical significance showed between the mean ratios of ADC bland PVT / ADC HCC tumor and ADC malignant PVT/ ADC HCC tumor, which were (1.78 ± 0.32 SD) and (1.13 ± 0.25 SD) respectively.
4. A cut off value of (≤1.385) for the mean ratio ADC PVT / ADC HCC tumor was calculated using ROC curve. It proved to be highly diagnostic of malignancy with AUC (0.953), P value (0.006), sensitivity (93.75%), specificity (75%), PPV (93.7%), and NPV (75%).

1.  DW MRI is a  non invasive imaging technique with great ability in tissue characterization, combined with mean ADC values to differentiate between bland and malignant PVT through qualitative and quantitative methods respectively.

2. A cut off value of (≤ 1.1 × 10-3 mm2/sec) for mean ADC of PVT, as  well as a cut off value of (≤1.385) for the mean ratio ADC PVT/ ADC HCC tumor were reached  and both  proved to be highly diagnostic of malignancy

1. The use of DWI sequences in conjunction with all dynamic contrast enhanced MRI liver studies, for confident differentiation between bland and malignant PVTT.
2. DW MRI can be used confidently as an alternative in case of patients contraindicated to contrast material
3. Accurate diagnosis of PVT type, helps in deciding the treatment plan.