Visibility of the graft hepatic artery using superb microvascular imaging in liver transplantation recipients: initial experience

Abstract

Background Hepatic artery (HA) obstruction is one of the most threatening complications following liver transplantation (LT); however, conventional color Doppler imaging (CDI) suffers from technical limitations regarding the visualization of fine vessels and low-velocity blood flow. Purpose To test the visibility of HA in postoperative evaluation of LT using a superb microvascular imaging (SMI). Material and Methods This retrospective study was approved by our institutional review board. Fifty-five consecutive patients (58 grafts; mean age = 56 years) who underwent LT with Doppler ultrasonography (US) on postoperative day 1 were included. We compared the subjective visibility of HA and objective measurements of HA caliber, visible HA length on CDI, monochrome SMI (mSMI), contrast-enhanced mSMI (CE-mSMI), and contrast harmonic imaging (CHI). Reproducibility of HA caliber measurements on SMI techniques were also evaluated by using intraclass correlation coefficients (ICCs). Results The subjective image quality for visibility of HA tended to be graded higher with mSMI than CDI, and with CE-mSMI than mSMI ( P < 0.001). The overall reproducibility of HA caliber measurements was good to excellent for both mSMI and CE-mSMI (ICC = 0.674-0.855). HA caliber measurements on mSMI and CE-mSMI strongly correlated with CHI ( R = 0.785, 0.798, P < 0.001), while mean HA length on mSMI was significantly longer than on CDI (1.88 ± 0.83 vs. 1.42 ± 1.01cm, P = 0.004), and even longer on CE-mSMI (vs. 3.28 ± 1.11 cm, P < 0.001). Conclusion The mSMI technique shows good reproducibility and correlates well with currently used methods for postoperative evaluation of HA in LT recipients. It is further improved by administration of an US contrast agent.

Additional value of superb microvascular imaging for assessing hepatic arterial blood flow after pediatric liver transplantation

“…cSMI and mSMI demonstrated clinical applications for assessing the graft hepatic artery, and good interobserver reliability was indicated. Jang et al 32 reported that the SMI technique showed good reproducibility in adult liver transplant recipients.…”

Superb Microvascular Imaging (SMI) Compared with Color Doppler Ultrasound for the Assessment of Hepatic Artery in Pediatric Liver Transplants: A Feasibility Study

“…SMI has been tested to assess a broad spectrum of disorders, including breast tumors, thyroid nodules, carotid plaques, vascular endoleak, and focal liver lesions [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. However, there are still a few studies regarding SMI technique application during the routine follow-up of LT patients [ 18 , 29 ], particularly in pediatric recipients [ 17 ]. Therefore, we aimed to explore the potential of SMI in visualizing HA in pediatric LT recipients compared with CDI.…”

“…Our findings align with previous studies that explored SMI for HA assessment in adult liver recipients. Jang et al [ 29 ] compared SMI and CDI in LT patients. They concluded that SMI shows good reproducibility, correlates well with currently used methods for postoperative evaluation of HA in LT recipients, and is further improved by administering a US contrast agent.…”

New microvascular ultrasound techniques: abdominal applications

“…FNH: spoke-wheel pattern (41–67%). HCC: non-specific or irregular pattern (48–93%) Assessment of treatment response [ 18 ] Detection of residual intratumoral flow after transarterial chemoembolization Fibrosis staging [ 25 – 28 ] Vascular changes can predict the severity of fibrosis Diagnosis of steatosis [ 29 ] Vascular index inversely correlated with hepatic steatosis Assessment of liver transplant recipients [ 30 – 33 ] Improved visibility of the hepatic artery and diagnosis of hepatic artery thrombosis Gallbladder Diagnosis of acute cholecystitis [ 34 ] Superb microvascular imaging value predicted acute cholecystitis Diagnosis of gallbladder lesions [ 37 ] Superb microvascular imaging may help in the differential diagnosis Kidney Differential diagnosis between renal lesions [ 41 – 45 ] Improved detection of intratumoral vascularization. Malignant tumors: annular or ring-like flow pattern (65–67%) Diagnosis of acute pyelonephritis [ 46 ] Improved detection and diagnosis Evaluation of renal function [ 47 , 48 ] Cortical flow and vascular index correlated with the severity of chronic kidney disease Bladder Acute cystitis [ 50 ] Higher vascular index was associated with acute cystitis Vesicoureteral reflux [ 51 ] Demonstrated reversed ureteral jet and/or renal pelvic swirl sign Prostate Diagnosis of prostate cancer [ 52 , 53 ] Higher vascularity in malignant lesions and lesions with...…”