Doppler sonography of patients with and without acute cellular rejection after right-lobe living donor liver transplantation

Usefulness of Picture Archiving and Communication System-Based Quantitative Ultrasound Measurements in Evaluation of Allograft Dysfunction in Patients With Liver Transplantation

OBJECTIVE

The aim of this study was to assess the usefulness of picture archiving and communication system (PACS)-based quantitative grayscale ultrasonography (US) measurements in detecting allograft dysfunction in posttransplant patients.

METHODS

In this retrospective study, 116 patients with liver transplantation who underwent biopsy for allograft evaluation were recruited from the database. All participants had US images prior to procedure. Normal, acute cellular rejection (ACR), recurrent hepatitis (Hep), or combined (ACR/Hep) groups were generated based on pathology results. Region of interests were drawn for liver and rectus abdominus muscle to perform quantitative US analysis. The liver/muscle mean ratio (L/M) and heterogeneity index (HI; liver standard deviation/liver mean) were obtained. The ratios of groups were compared, and receiver-operating-characteristic analysis was performed.

RESULTS

There was a significant difference between normal (n = 16) and each of other groups (ACR, 39; Hep, 36; combined, 25) for L/M and HI (P < 0.05). No significant difference was detected between ACR, Hep, and combined groups. The areas under the curve for L/M and HI were 0.755 (moderate) and 0.817 (good), respectively. To differentiate abnormal (ACR, Hep, and combined) from normal allografts sensitivity, specificity, PPV, and NPV were 50.0%, 87.5%, 96.2%, and 21.9% for cut point of L/M ≥1 and 84.0%, 68.8%, 94.4%, and 40.7% for cut point of HI ≥0.2 with odds ratios of 7.52 (for L/M ≥1) and 13.10 (for HI ≥0.2), respectively (P < 0.01).

CONCLUSIONS

L/M has moderate and HI has good discrimination of normal from abnormal allograft in liver transplant patients. PACS-based quantitative US measurements is an objective, easy to use, noninvasive auxiliary tool to discriminate hepatic allograft dysfunction.

Value of Doppler ultrasonography in predicting clinical outcomes for patients with acute cellular rejection after liver transplantation

PURPOSE

This study investigated the value of Doppler ultrasonography in predicting clinical outcomes after antirejection treatment for patients with acute cellular rejection (ACR) following liver transplantation (LT).

METHODS

This retrospective study included 84 patients who were pathologically diagnosed with ACR and received antirejection treatment within 90 days following LT. Two radiologists searched for abnormal Doppler parameters at ACR diagnosis and within 7 days after antirejection treatment initiation, including portal blood velocity (PBV) <20 cm/s, hepatic artery resistive index <0.5, and a monophasic hepatic vein flow pattern. Interval PBV changes were also evaluated. The frequencies of abnormal Doppler parameters and PBV changes were compared by treatment outcome.

RESULTS

The frequency of abnormal PBV in the early post-treatment phase (PBVearly post-treatment) was significantly higher among poor responders (50.0% [10/20]) than among good responders (7.8% [5/64]) (P<0.001). The sensitivity, specificity, and accuracy of abnormal PBVearly post-treatment as a predictor of poor response to antirejection treatment were 50.0% (10/20), 92.2% (59/64), and 82.1% (69/84), respectively. A decrease (>10%) from the PBV at event (PBVevent) to PBVearly post-treatment was significantly more common among poor responders (50.0% [10/20]) than among good responders (20.3% [13/64]) (P=0.019). The sensitivity, specificity, and accuracy of this PBV decrease in predicting poor treatment response were 50.0% (10/20), 79.7% (51/64), and 72.6% (61/84), respectively.

CONCLUSION

Abnormal PBVearly post-treatment and a decrease between PBVevent and PBVearly post-treatment were significantly associated with poor treatment response in patients with ACR after LT. Consequently, Doppler ultrasonography may be useful for predicting clinical outcomes in these patients.

Use of blood oxygen level-dependent magnetic resonance imaging to detect acute cellular rejection post-liver transplantation

OBJECTIVES

Acute cellular rejection (ACR) is a major immune occurrence post-liver transplant that can cause abnormal liver function. Blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) can be used to evaluate liver disease, but it has not been utilized in the diagnosis of ACR post-liver transplant. Therefore, the purpose of this study is to evaluate the diagnostic performance of BOLD MRI and to monitor treatment response in recipients with ACR.

METHODS

This prospective study was approved by the local institutional review board. Fifty-five recipients with highly suspected ACR were enrolled in this study. Each patient underwent hepatic BOLD MRI, blood biochemistry, and biopsy before treatment. Of 55 patients, 19 recipients with ACR received a follow-up MRI after treatment. After obtaining the R2* maps, five regions-of-interest were placed on liver parenchyma to estimate the mean R2* values for statistical analysis. Receiver operating characteristic curve (ROC) analysis was performed to assess the diagnostic performance of R2* values in detecting patients with ACR.

RESULTS

The histopathologic results showed that 27 recipients had ACR (14 mild, 11 moderate, and 2 severe) and their hepatic R2* values were significantly lower than those of patients without ACR. ROC analysis revealed that the sensitivity and specificity of the R2* values for detection of ACR were 82.1% and 89.9%, respectively. Moreover, the R2* values and liver function in patients with ACR significantly increased after immunosuppressive treatment.

CONCLUSION

The non-invasive BOLD MRI technique may be useful for assessment of hepatic ACR and monitoring of treatment response after immunosuppressive therapy.

KEY POINTS

• Patients with acute cellular rejection post-liver transplant exhibited significantly decreased R2* values in liver parenchyma. • R2* values and liver function were significantly increased after immunosuppressive therapy. • R2* values were constructive indicators in detecting acute cellular rejection due to their high sensitivity and specificity.

Hematological and biochemical characteristics and diagnostic imaging results in acute T cell-mediated rejection after pediatric liver transplantation

BACKGROUND

Liver biopsy is the gold standard for diagnosing TCMR after LT. However, complications caused by liver biopsy may occur especially during the immediate post-transplantation period and other effective methods for predicting TCMR have not been established. Thus, we investigated whether hematological and biochemical characteristics and Doppler ultrasonography findings are associated with acute TCMR.

METHODS

A multiple logistic regression analysis was performed to identify the prognostic factors of acute TCMR, defined as a RAI ≥4. Then, a ROC curve analysis was conducted to evaluate for diagnostic performance. The relationship between prognostic factors and each histological category of RAI was investigated.

RESULTS

Eighty-nine liver biopsies were performed on 85 patients between January 2012 and December 2019. The RAI of 62 (69.7%) liver biopsies was ≥4. AEC (×10⁴ /μl), direct bilirubin level (mg/dl), and MHVV (cm/s) were found to be associated with acute TCMR (OR: 4.96, 95% CI: 1.44-17.0, p = .011; OR: 1.41, 95% CI: 1.04-1.91, p = .025; OR: 1.05, 95% CI: 1.02-1.08, p < .001, respectively). The area under the ROC curves for predicting acute TCMR was 0.86 (95% CI: 0.78-0.94). There was a correlation between AEC, direct bilirubin level, and MHVV as well as the severity of RAI.

CONCLUSIONS

AEC, direct bilirubin level, and MHVV were the independent risk factors for acute TCMR. This study could provide information regarding the identification of patients requiring liver biopsy.

Acoustic Radiation Force Impulse and Doppler Ultrasonography: Comprehensive Evaluation of Acute Rejection After Liver Transplantation

OBJECTIVES

The aim of our study was to evaluate the clinical application of color Doppler flow imaging (CDFI) and acoustic radiation force impulse (ARFI) for the diagnosis of acute rejection after liver transplantation.

METHODS

B-Mode CDFI and ARFI assessments were performed in 76 patients who underwent biopsy after liver transplantation at our institution, between October 2011 and October 2014. The study group included 56 patients with acute rejection confirmed by biopsy, with 20 patients whose liver function recovered within 1 month of transplantation forming the control group. Anteroposterior diameter of the liver, hemodynamic index (consisting of the portal vein diameter, portal vein flow velocity, and hepatic vein flow waveform), and ARFI shear wave velocity (SWV) were measured. We used logistic regression modeling and receiver operating curve to evaluate between-group differences.

RESULTS

Compared with the control group, patients with acute rejection exhibited increased anteroposterior diameter (P = .035) and change in hemodynamic index (P = .021), including increased portal vein diameter, decreased portal vein flow, and loss of triphasic waveform of hepatic vein flow. Acoustic radiation force impulse SWV was markedly increased in the acute rejection group (P < .001). The correlation r-value of measured parameters to acute rejection diagnosis was 0.253 for anterioposterior diameters, 0.271 for change in hemodynamic index, and 0.721 for increased SWV. Shear wave velocity and change in the hemodynamic index had diagnostic value, with an area under the receiver operating curve of 0.933.

CONCLUSIONS

Combining CDFI with ARFI was useful for the diagnosis of acute rejection after liver transplantation.

Contrast-Enhanced Ultrasound Using Perfluorobutane-Containing Microbubbles in the Assessment of Liver Allograft Damage: An Exploratory Prospective Study

This prospective study investigated the usefulness of contrast (perfluorobutane-containing microbubbles)-enhanced ultrasound in the non-invasive assessment of liver allograft damage. Forty-one liver recipients underwent contrast-enhanced ultrasound followed by a liver biopsy. The hepatic filling rate (time between the arrival of contrast agent in the right hepatic artery and the maximum intensity of hepatic parenchyma) and parenchymal intensity difference before and after instantaneous high-power emission in the Kupffer phase were measured. Patients with allograft damage had higher hepatic filling rates and lower parenchymal intensity differences than those without damage (42.0 ± 16.9 vs. 30.5 ± 7.7 s, p = 0.005; 6.1 ± 7.4 vs. 16.6 ± 16.1 dB, p = 0.047, respectively). In the diagnosis of liver allograft damage, hepatic filling rate and parenchymal intensity difference had sensitivities of 61.5% and 90.9% and specificities of 92.6% and 63.6% using cutoffs of >38.5 s and ≤10.3 dB, respectively. In conclusion, contrast-enhanced ultrasound may be a promising tool in the detection of liver allograft damage.