Comparative Study Of Diffusion-weighted Imaging (DWI) In The Diagnosis Of Hepatocellular Carcinoma

Objective: To prospectively evaluate whether DWI with mSENSE (mSENSE-DWI)can help to improve image quality and affect the calculation of lesion's ADC,compared with DWI with conventional phase encoding(conventional DWI)in patientswith small HCC lesions.Materials and methods: 32 patients with 47 small HCC lesions underwentsingle-shot spin-echo echo-planar DWI with conventional phase encoding andmSENSE. Three b values of 300, 500 and 800 sec/mm² were used. mSENSE-DWIand conventional DWI were compared for image quality, and CNR with different bvalue. Lesion's ADC with conventional phase encoding and mSENSE at MR imagingwere also observed and compared; Friedman test and matched-pairs Wilcoxon signedrank test was used to test statistical significance.Results: Higher image quality scores were achieved at mSENSE-DWI group (P<0.01) and CNR of the lesions was also higher than that of conventional DWI (P<0.01) with the same b value. There was no significant difference in the measurementof lesion's ADC between mSENSE-DWI group and conventional DWI group withhigh b value(500 and 800 sec/mm², P=0.383,0.388 respectively). With the increase ofb value, the image quality , CNR and ADC decreased at mSENSE-DWI group as wellas that of conventional DWI group(P<0.01).Conclusion: Higher quality images can be achieved in liver DWI with mSENSEwithout compromising small HCC lesion's ADC calculation.Objective: To compare the sensitivity of DWI and 2D DCE MRI for the detection ofsmall HCC lesion (≤ 3 cm)in the patients with chronic liver disease, and evaluate theclinical value for DWI.Materials and methods: 54 patients with 74 small HCC lesions(≤3cm) underwentDWI and 2D DCE MRI at the same time. The DWI was performed using mSENSEtechnology with different b value(300 500 800sec/mm²). The dynamic MRIexamination was performed using 2D FLASH sequence. Two observersindependently interpreted the images in random order, separately. The diagnosticperformance of each technique was evaluated using the ROC curves. The sensitivityand positive predictive value were also calculated.Results: The mean area under the ROC curve (Az) of DWI (0.95, 0.86) wasstatistically higher than that of 2D DCE MRI (0.86, 0.64) for all small HCC lesionsand MHCC lesions (P<0.01). The sensitivities of DWI for two observers weresignificantly higher than those of 2D DCE MRI for all small lesions and for MHCC(P<0.05); For MHCC, the sensitivity of DWI and 2D DCE MRI was 95.8-96%,62.5-68% respectively, The positive predictive value for MHCC lesions in DWI wasstatistically higher than in 2D DCE MRI(P<0.05).Conclusion: For the detection of small HCC lesions in the patients with chronic liverdisease, DWI is more sensitive than 2D DCE MRI. It can provide valuableinformation in the differential diagnosis.Part IIIThe value of diffusion-weighted imaging in differentiating SHCC from Hepatichyperplastic nodulesObjective: To evaluate the value of DWI of liver in differentiating SHCC from hepatic hyperplastic nodules(including DN and FNH).Materials and methods: the DWI of liver were performed with mSENSE technology under b value 500 sec/mm², the signal feature of 28 SHCC lesions 10 DN lesions and11 FNH lesions confirmed with surgery and pathology were observed retrospectively and ADC value of all lesions were calculated and analyzed statistically. Results: All of 28 SHCC lesions showed as hyperintense on DWI, isointensity or hypointensity was showed in 10 DN lesions, hyperintensity was showed in 11 FNH lesions, the mean ADC value of SHCC, DN and FNH was 1.30±0.21 X10^-3mm²/sec, 1.51±0.22 X10^-3mm²/sec, 1.85±0.33X10^-3mm²/sec respectively. There was statistically significant difference in ADC value between SHCC lesions and DN lesions (P=0.021), between SHCC lesions and FNH lesions(P=0.000), between SHCC lesions and surrounding hepatic tissues(P=0.001), between FNH lesions and surrounding hepatic tissues(P=0.006); there was no statistically significant difference in ADC value between DN lesions and surrounding hepatic tissues(P=0.575). Combination of ADC value and signal features, The accuracy of DWI for differentiating SHCC from hepatic hyperplasia nodules was 89.8%. The accuracy of dynamic contrast-enhanced was 69.4%. The combination of dynamic contrast-enhanced and DWI had accuracy of 97.9% in differential diagnosis. Conclusion: Combined with ADC value and signal features, DWI of liver can provide additional important information in differentiating SHCC from hepatic hyperplastic nodules.Part IVInitial investigation of HCCs on its Correlation between DWI and HCCDifferentiations, PCNA expressionObjective: To investigate the correlations between ADC value of HCC on DWI and tumor differentiation and PCNA expression.Materials and methods: 27 HCCs cases with 29 lesions confirmed by pathology were collected in this study. The DWI of liver were performed with mSENSE technology under b value 500sec/mm² for all cases, the ADC value of HCC were calculated on ADC mapping. The pathological examination with HE stain for cell differentiation, irnmunohistochemistrical exams for PCNA were performed. All lesions were also divided according to Edmondson grading into two groups: group one (high differentiation) including Edmondson grade I, I-II and II; group two (lowdifferentiation) including Edmondson grade II-II1, III, III-IV and IV; The all 29 leisons were quantitatively evaluated N/C area ratio, immunohistochemistrically for PCNA positive index. The correlation between ADC value and cell differentiation PCNA expression were analyzed.Results: Hyperintensity was demonstrated on DWI for all HCC lesions. The ADC value of HCC lesions was 0.86-1.69X10^-3mm²/sec. According to the Edmondson grade, there was 14 high-differentiated lesiosns and 15 low-differentiated lesions. There was no significant difference in ADC value between high-differentiated and low-differentiated lesions(p=0.913). There were no significant correlations between ADC value and the tumor N/C area ratio(r=0.149) and PCNA index(r=0.364). Conclusion: At the DWI of liver with b value 500sec/mm², ADC value of HCC may not be used to evaluate the tumor cell differentiation and invasion in vivo study.