الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
HCC is the 5th most common cancer worldwide with up to 20% of HCC cases are associated with MVI. PVTT is associated with the worst outcome, thus the differentiation between bland and malignant portal vein thrombus is crucial in the diagnosis, prognosis, therapeutic plans and survival rate.
Different imaging modalities play a role in the diagnosis of HCC with PVTT such as ultrasound with color doppler, triphasic CT liver and dynamic contrast enhanced MRI liver.
MRI is clinically a powerful imaging technique and superior to the other imaging modalities in tissue characterization. DW MRI is an emerging non-invasive imaging modality that doesn’t need contrast agent. It allows differentiation between different benign and malignant lesions, helping in tumor staging and detection of post-operative recurrent or residual masses. Even in the case of dynamic contrast-enhanced MRI, DWI yields supportive evidence and increases the confidence of a specific diagnosis.
The aim of our study was to evaluate the role of DW MRI in combination with mean ADC values in differentiating between bland and malignant portal vein thrombus.
Our study was carried on 25 patients referred from the Hepatobiliary Unit, Surgery Department, and the Clinical Oncology Department to the Department of Radiodiagnosis and Intervention, Alexandria Main University Hospital. The patients underwent DCE MRI liver and proved to have portal vein thrombus whether bland or tumoral. The enhancement pattern of the thrombus on the dynamic phases was used as our reference.
Ten bland PVT and 16 malignant PVT were detected, with a total of 26 PVT, this was due to the presence of a concomitant bland and malignant PV thrombi within the same patient.
All 16 PVTT were associated with primary HCC tumor, while only 4 bland PVT were associated with primary HCC tumor. The remaining 6 bland PVT were associated with cirrhotic liver.
Our 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 x10-3 mm2/sec ± 0.13 SD) respectively. 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%)
Additionally, our study showed statistical significance 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. 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%).
We have proved in our research that DW MRI with mean ADC values and mean ADC ratios have high positive predictive value for diagnosing PVTT and highly sensitive in tissue characterization to differentiate between bland and malignant portal vein thrombus.