Nuclear medicine techniques in transplantation

Hepatobiliary Scintigraphy to Evaluate Biliary Complications of Pediatric Liver Transplantation: An Account of an Experience

INTRODUCTION

 Hepatobiliary scintigraphy (HS) is a noninvasive imaging technique whose use in the follow-up of liver transplantation has not been duly documented. The main objective of this study is to describe the experience of using this technique to detect biliary complications in pediatric patients following liver transplantation.

MATERIALS AND METHODS

 A retrospective, observational, and descriptive study involving 86 pediatric patients who had undergone liver transplantation between 2013 and 2018. Of the 86, 31 had undergone at least one HS during their postoperative period.

RESULTS

 A total of 45 studies were performed on 31 patients (36% of the patients undergoing transplantation during that time period). Patient ages ranged from 5 to 204 months (mean = 50 months). A total of 22 transplants (71%) were from living donors and 9 (29%) were from cadaveric donors. Of the 45 studies, 22 were positive for biliary complications, and all of them had an impact on clinical decision-making. The remaining 23 studies were negative. Of these 23, 19 continued under medical treatment and the other four underwent an additional intervention with positive surgical outcomes in all cases. All scintigraphy studies revealed hepatocellular dysfunction and cholestasis.

CONCLUSION

 The HS is a useful, noninvasive, and diagnostic procedure for the early diagnosis of biliary complications that may impact the evolution of disease in liver transplant patients. It allows the treating physician to make a more informed decision regarding expectant management, surgical management, or a less invasive course of action for transplantation complications.

[18F]FDG PET/CT imaging disproves renal allograft acute rejection in kidney transplant recipients with acute kidney dysfunction: a validation cohort

PURPOSE

[18F]FDG PET/CT may predict the absence of acute allograft rejection (AR) in kidney transplant recipients (KTRs) with acute kidney injury (AKI). Still, the proposed threshold of 1.6 of the mean of mean standardized uptake values (mSUVmean) in the renal parenchyma needs validation.

METHODS

We prospectively performed 86 [18F]FDG PET/CT in 79 adult KTRs who underwent per-cause transplant biopsy for suspected AR. Biopsy-proven polyoma BK nephropathies (n = 7) were excluded. PET/CT was performed 192 ± 18 min after administration of 254.4 ± 30.4 MBq of [18F]FDG. The SUVmean was measured in both upper and lower poles of the renal allograft. One-way analysis of variance (ANOVA) and Tukey's studentized range test were sequentially performed. The receiver operating characteristic (ROC) curve was drawn to discriminate "AR" from non-pathological ("normal" + "borderline") conditions.

RESULTS

The median age of the cohort was 55 [43; 63] years, with M/F gender ratio of 47/39. The mean eGFR was 31.9 ± 14.6 ml/min/1.73m2. Biopsies were categorized in 4 groups: "normal" (n = 54), "borderline" (n = 9), "AR" (n = 14), or "others" (n = 2). The median [min; max] mSUVmean reached 1.72 [1.02; 2.07], 1.97 [1.55; 2.11], 2.13 [1.65, 3.12], and 1.84 [1.57; 2.12] in "normal," "borderline," "AR," and "others" groups, respectively. ANOVA demonstrated a significant difference of mSUVmean among groups (F = 13.25, p < 0.0001). The ROC area under the curve was 0.86. Test sensitivity and specificity corresponding to the threshold value of 1.6 were 100% and 30%, respectively.

CONCLUSION

[18F]FDG PET/CT may help noninvasively prevent inessential transplant biopsies in KTR with AKI.

Hepatobiliary scintigraphy in the study of complications in adult patients after liver transplant. Description of the experience

OBJECTIVE

To show the experience of the use of hepatobiliary scintigraphy in patients with suspected complications after liver transplantation in a high complexity centre.

MATERIAL AND METHOD

Retrospective, observational and descriptive study. All consecutive adult patients with liver transplantation between January 2013 and February 2018 were included, with one or more hepatobiliary scintigraphy during the early or late postoperative period. A total of 58 studies were analyzed in 38 patients (22 men and 16 women). Mean age: 48 years. In 34/38: cadaverous donor (89%), and in 4 (11%): a living donor. Demographic data and relevant information regarding the transplant were obtained, and the result was related to the surgical findings to determine the correlation between them. The influence of the test on the final clinical decisions was evaluated.

RESULTS

Findings: 9 scans (14%) were normal, 36 studies were negative, and 21 were positive for biliary complications. Of the total of 58 studies, 50 (86%) had impact on the clinical behaviour of observation or intervention. All the patients with findings of biliary complications (21/21; 100%) had clinical repercussion since 18/21 patients were taken to invasive studies or treatments, and 3/21 patients continued in medical management for findings of non-surgical biliary complications. In 14/18 patients taken to studies or procedures, correlation was found with the scintigraphic study. In 24/36 (66%) of patients with negative scintigraphy, an impact on clinical behaviour was found.

CONCLUSION

Hepatobiliary scintigraphy is a simple, non-invasive, reliable, current and available form for the early study of biliary complications in patients with liver transplantation. Important hepatocellular dysfunction should be taken into account as a frequent cause of false negative studies.

[18F-FDG positron emission tomography in non-oncological renal pathology: Current indications and perspectives]

Positron emission tomography combined with computed tomography (PET/CT) is a nuclear imaging technique which provides anatomical and functional information. PET/CT is increasingly used in non-oncological nephrology since conventional radiological approaches after injection of contrast agents are relatively contra-indicated in patients with chronic kidney disease (CKD). PET/CT after i.v. injection of ¹⁸F-fluoro-deoxy-glucose (FDG) is not toxic and is characterized by a high sensitivity. The level of irradiation (∼5mSv) is acceptable. CKD does not significantly influence tissue uptake of ¹⁸F-FDG. The purpose of the present review aims at detailing the non-oncological indications of ¹⁸F-FDG PET/CT in general nephrology and after kidney transplantation. Particularly, ¹⁸F-FDG PET/CT appears useful in the diagnosis of cyst infection in patients with autosomal dominant polycystic kidney disease, as well as in the characterization of retroperitoneal fibrosis. In kidney transplant recipients, ¹⁸F-FDG PET/CT may help in the diagnostic work-up of suspected acute rejection, thereby eventually avoiding unnecessary kidney transplant biopsy. Perspectives in ¹⁸F-FDG PET/CT imaging are discussed, including innovative approaches of image analysis.