Diagnostic performance of [(18)F]fluorodeoxyglucose positron emission tomography-computed tomography in cyst infection in patients with autosomal dominant polycystic kidney disease

Standardized 4-point scoring scale of [18F]-FDG PET/CT imaging helps in the diagnosis of renal and hepatic cyst infections in patients with autosomal dominant polycystic kidney disease: a validation cohort

Background

Autosomal dominant polycystic kidney disease (ADPKD) is prone to multiple complications, including cyst infection (CyI). 2-Deoxy-2-[18F]fluoro-d-glucose positron emission tomography/computed tomography ([18F]-FDG PET/CT) imaging has proved useful in the diagnosis of renal and hepatic CyI. A 4-point scale comparing the uptake of [18F]-FDG in the suspected infected cyst versus the hepatic physiological background has been recently proposed. We performed an independent validation of this semi-quantitative scoring system.

Methods

All ADPKD patients hospitalized between January 2009 and November 2019 who underwent an [18F]-FDG PET/CT for suspected CyI were retrospectively identified using computer-based databases. Medical files were reviewed. CyI was conventionally defined by the combination of fever (≥38°C), abdominal pain, increased plasma C-reactive protein levels (≥70 mg/L), absence of any other cause of inflammation and favourable outcome after ≥21 days of antibiotics. [18F]-FDG uptake of the suspected CyI was evaluated using a 4-point scale comparing the uptake of [18F]-FDG around the infected cysts with the uptake in the hepatic parenchyma. Statistics were performed using SAS version 9.4.

Results

Fifty-one [18F]-FDG PET/CT scans in 51 patients were included, of which 11 were cases of CyI. The agreement between the 4-point scale and the gold-standard criteria of CyI was significant [odds ratio of 6.03 for CyI in case of a score ≥3 (P = .014)]. The corresponding sensitivity, specificity, and positive and negative predictive values of [18F]-FDG PET/CT using the 4-point scale were 64% [Clopper-Pearson 95% confidence interval (CI) 30%-89%], 78% (95% CI 62%-89%), 44% (95% CI 20%-70%) and 89% (95% CI 73%-97%), respectively.

Conclusions

Our independent validation cohort confirms the use of a semi-quantitative 4-point scoring system of [18F]-FDG PET/CT imaging in the diagnosis of CyI in patients with ADPKD. Considering its performance metrics with high specificity and negative predictive value, the scoring system is particularly useful to distinguish other causes of clinical inflammation than CyI and as such avoid unnecessarily long antibiotic treatment.

Incidence, risk factors and outcomes of kidney and liver cyst infection in kidney transplant recipient with autosomal dominant polycystic kidney disease

Introduction

Methods

Results

Conclusion

Position paper on liver and kidney diseases from the Italian Association for the Study of Liver (AISF), in collaboration with the Italian Society of Nephrology (SIN)

Liver and kidney are strictly connected in a reciprocal manner, in both the physiological and pathological condition. The Italian Association for the Study of Liver, in collaboration with the Italian Society of Nephrology, with this position paper aims to provide an up-to-date overview on the principal relationships between these two important organs. A panel of well-recognized international expert hepatologists and nephrologists identified five relevant topics: 1) The diagnosis of kidney damage in patients with chronic liver disease; 2) Acute kidney injury in liver cirrhosis; 3) Association between chronic liver disease and chronic kidney disease; 4) Kidney damage according to different etiology of liver disease; 5) Polycystic kidney and liver disease. The discussion process started with a review of the literature relating to each of the five major topics and clinical questions and related statements were subsequently formulated. The quality of evidence and strength of recommendations were graded according to the GRADE system. The statements presented here highlight the importance of strong collaboration between hepatologists and nephrologists for the management of critically ill patients, such as those with combined liver and kidney impairment.

PET/CT Imaging for Personalized Management of Infectious Diseases

Positron emission tomography combined with computed tomography (PET/CT) is a nuclear imaging technique which is increasingly being used in infectious diseases. Because infection foci often consume more glucose than surrounding tissue, most infections can be diagnosed with PET/CT using 2-deoxy-2-[18F]fluoro-D-glucose (FDG), an analogue of glucose labeled with Fluorine-18. In this review, we discuss common infectious diseases in which FDG-PET/CT is currently applied including bloodstream infection of unknown origin, infective endocarditis, vascular graft infection, spondylodiscitis, and cyst infections. Next, we highlight the latest developments within the field of PET/CT, including total body PET/CT, use of novel PET radiotracers, and potential future applications of PET/CT that will likely lead to increased capabilities for patient-tailored treatment of infectious diseases.

FDG PET/CT for Detection of Infectious Complications Following Solid Organ Transplantation

Infectious complications after solid organ transplantation (SOT) are often more severe and remain a diagnostic challenge due to vague and atypical clinical presentations. Diagnostic performance of conventional diagnostic tools is frequently inadequate which may lead to delayed diagnosis with the risk of poorer outcomes. This literature review aimed to investigate the current evidence on the use of ¹⁸F-fluoro-deoxy-glucose (FDG) Positron Emission Tomography (PET)/computer tomography (CT) in infectious complications after SOT. Based on search in PubMed, Medline, and Cochrane databases, 13 articles and 46 case reports were included. For inclusion, articles were to include data on patients with infectious complications after SOT, and where FDG PET/CT was part of the work-up. Final searches were conducted on 02 September 2020. Overall, in the absence of initial diagnostic clues, FDG PET/CT should be considered as the imaging technique of choice as it may guide further investigations and eventually reveal the diagnosis in most of the patients. However, the available literature of the role of FDG PET/CT in SOT recipients with infectious complications is scarce and well-designed prospective studies including control groups are warranted to establish the role of FDG PET/C/ in SOT recipients. The main drawback of FDG PET/CT is the lack of ability to differentiate between cancer and infectious diseases which are both highly prevalent in this patient group. Accordingly, the main reasons for "false" results of FDG PET/CT is the misdiagnosis of cancer in benign inflammatory or infectious processes, information which nonetheless can be useful.

18F-FDG PET/CT in cyst infection in autosomal dominant polycystic kidney disease

Infection of a cyst within an autosomal dominant polycystic kidney disease (ADPKD) is a serious complication. Diagnosis with conventional imaging techniques such as ultrasonography, computed tomography (CT), and magnetic resonance imaging can be sometimes challenging. The definite diagnosis is analysis of the cyst fluid, but cyst punctures can cause bleeding, rupture, and contamination of adjacent cysts. Recently, FDG PET/CT has been reported as a sensitive tool for detection of cyst infection. We describe a case of 63-year-old woman with infected cysts in the left kidney, in whom accurate diagnosis was made on FDG PET/CT. FDG PET/CT is an important investigation in patients with fever of uncertain etiology, where renal cyst infection is a possible cause, but other etiologies also need to be ruled out.

In-hospital management of acute complicated urinary tract infections

Upper tract urinary tract infections that require hospitalization have been the focus of national recommendations in 2018 by the French society of infectious diseases (Spilf). We here propose to discuss several complex-challenging situations: severe infection with sepsis, pyelonephritis in the pregnant woman, management of infections involving multiresistant bacteria and infection in polycystic kidney disease.

Two cases of fungal cyst infection in ADPKD: is this really a rare complication?

Background

Cyst infection is a prevalent complication in autosomal dominant polycystic kidney disease (ADPKD) patients, however therapeutic and diagnostic approaches towards this condition remain unclear. The confirmation of a likely episode of cyst infection by isolating the pathogenic microorganism in a clinical scenario is possible only in the minority of cases. The available antimicrobial treatment guidelines, therefore, might not be appropriate to some patients.

Case presentation

We describe two unique cases of kidney cyst infection by Candida albicans, a condition that has not been previously described in literature. Both cases presented clear risk factors for Candida spp. infection. However, since there was no initial indication of cyst aspiration and culture, antifungal therapy was not immediately started and empirical treatment was initiated as recommended by the current guidelines. Antifungal treatment was instituted in both cases along the clinical course, according to their specificities.

Conclusion

Our report highlights the possibility of Candida spp. cyst infection. Failure of clinical improvement with antibiotics should raise the suspicion of a fungal infection. Identification of infected cysts should be pursued in such cases, particularly with PET-CT, and when technically possible followed by cyst aspiration and culture to guide treatment. Risk factors for this condition, such as Candida spp. colonization, previous antimicrobial therapy, hemodialysis, necrotizing pancreatitis, gastrointestinal/hepatobiliary surgical procedure, central venous catheter, total parenteral nutrition, diabetes mellitus and immunodeficiency (neutropenia < 500 neutrophils/mL, hematologic malignancy, chemotherapy, immunosuppressant drugs), should be also considered accepted criteria for empirical antifungal therapy.

[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.

Infected cyst in patients with autosomal dominant polycystic kidney disease: Analysis of computed tomographic and ultrasonographic imaging features

Purpose

To investigate the imaging features of cyst infection in autosomal dominant polycystic kidney disease (ADPKD) patients using computed tomography (CT) and ultrasonography (US).

Materials & methods

The institutional review board approved this retrospective study. Fifty-one episodes with proven cyst infection in forty-three ADPKD patients were included. Two experienced abdominal radiologists reviewed CT and US images and evaluated the following imaging features in consensus: cyst size, location, cyst shape, intracystic attenuation, intracystic echogenicity, intracystic heterogeneity, wall thickness, the presence of fluid-fluid level, septation, intracystic gas, pericystic fat infiltration, and pericystic hyperemia. Intracystic attenuation was measured for all infected cysts and two presumed normal cysts and compared using the Wilcoxon rank-sum test.

Results

On CT scans, the median size of infected cysts was 5.5 cm (range: 2.3–18.8 cm) and 46 of 51 (90.2%) infected cysts were located in the subcapsular region. Most (48 of 51, 94.1%) infected cysts showed lobulated, focal bulging or irregular shape. Discernible wall thickening (84.1%) was the most frequently found imaging feature of infected cysts followed by relatively higher intracystic attenuation compared to normal cysts (79.1%) and pericystic fat infiltration (52.9%). Fluid/fluid level was found in 3 of 51 (5.9%) infected cysts and intracystic gas was found in 3 of 51 (5.9%) infected cysts, respectively. For hepatic cysts, 11 of 14 (78.6%) infected cysts showed pericystic hyperemia. Intracystic attenuation was significantly higher in infected cysts (median; 19.0 HU) than in presumed normal cysts (median; 8.5 HU) (P<0.001), and exceeded 25 HU in 18 (35.3%) of 51 infected cysts. Among the 41 infected cysts for which US images were available, 35 (85.1%) showed heterogeneous echogenicity.

Conclusion

Minute imaging features such as minimal wall thickening or relatively high attenuation compared to normal cysts would be helpful to detect infected cysts in ADPKD patients.

18F-FDG PET/CT in Autosomal Dominant Polycystic Kidney Disease Patients with Suspected Cyst Infection

The objective of this study was to determine the value of ¹⁸F-FDG PET/CT for diagnosing renal or hepatic cyst infection in patients with autosomal dominant polycystic kidney disease (ADPKD). Methods: This retrospective, single-center study included all patients who had ADPKD and underwent ¹⁸F-FDG PET/CT because of suspected cyst infection between 2010 and 2017. Results: Thirty ¹⁸F-FDG PET/CT scans of 30 individual patients were included; 19 of them had positive results for cyst infection. According to a previously established clinical and biochemical reference standard, ¹⁸F-FDG PET/CT achieved a sensitivity of 88.9%, a specificity of 75.0%, a positive predictive value of 84.2%, and a negative predictive value of 81.8% for the diagnosis of cyst infection. In 5 cases, ¹⁸F-FDG PET/CT suggested that the symptoms could be explained by a different pathologic process, including pneumonia (n = 1), generalized peritonitis (n = 1), pancreatitis (n = 1), colitis (n = 1), and cholangitis (n = 1). The total duration of the hospital stay and the duration between the ¹⁸F-FDG PET/CT scan and hospital discharge for patients with ¹⁸F-FDG PET/CT scan results that were positive for cyst infection were significantly longer than those for patients with negative scan results (P = 0.005 and P = 0.009, respectively). Creatinine levels were significantly higher in patients with ¹⁸F-FDG PET/CT scan results that were positive for cyst infection than in patients with negative scan results (P = 0.015). Other comparisons of clinical parameters (age, sex, presence of fever [>38.5°C] for more than 3 d, abdominal pain, history of solid-organ transplantation and nephrectomy, and immune status), laboratory values (C-reactive protein level, leukocyte count, and estimated glomerular filtration rate), and microbiologic test results (blood and urine cultures) were not significantly different (P = 0.13-1.00) in patients with positive and negative ¹⁸F-FDG PET/CT scan results. Conclusion: ¹⁸F-FDG PET/CT is a useful imaging modality for the evaluation of patients with ADPKD and suspected cyst infection.

FDG-PET/CT for diagnosis of cyst infection in autosomal dominant polycystic kidney disease

Purpose

Cyst infections are a common complication in autosomal dominant polycystic kidney disease (ADPKD). Diagnosing these infections often remains challenging. Conventional imaging techniques such as ultrasonography, computed tomography (CT), and standard magnetic resonance imaging have several drawbacks and disadvantages. The purpose of this pictorial essay was to illustrate and discuss the potential value of ¹⁸F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET)/CT in diagnosing cyst infection in ADPKD.

Methods

Exemplary (ADPKD) patients who underwent FDG-PET/CT as part of their routine clinical work-up in our institution are presented to show the potential value and drawbacks of this imaging technique in diagnosing cyst infection. In addition, the current literature and guidelines on this topic were reviewed.

Results

FDG-PET/CT appears to be a sensitive method for the detection of cyst infection, but it is not infallible. Furthermore, FDG uptake in cysts and cyst-like lesions is not specific and clinical and radiological correlations are essential to improve specificity and minimize the risk of falsely discarding other diseases, in particular malignancy.

Conclusion

FDG-PET/CT seems to be a useful imaging modality to diagnose cyst infections in ADPKD. However, its exact diagnostic value has not been established yet due to the lack of a reliable reference standard in previous studies on this topic.

The Role of PET Scanning in the Evaluation of Patients With Kidney Disease

Patients with underlying kidney disease are often required to undergo imaging for a variety of purposes including diagnosis and prognosis. A test that is being increasingly used with for this group of patients is the positron emission test (PET) scan. In addition, combining the nuclear medicine technique (PET) with computed tomography scan allows additional imaging advantages over either alone. These imaging modalities are commonly used for a number of extrarenal indications (ie, cancer, coronary artery disease, central nervous system disease, infectious diseases, and others). They have also been used for diagnosis of acute tubulointerstitial nephritis, evaluation and management of retroperitoneal fibrosis, identifying infection within kidney and liver cysts, and distinguishing complex kidney cysts from kidney cancer in patients with underlying CKD. We will review PET scan utility in patients with kidney disease.

Glibenclamide impairs responses of neutrophils against Burkholderia pseudomallei by reduction of intracellular glutathione

The major risk factor for melioidosis, an infectious disease caused by B. pseudomallei, is diabetes mellitus. More than half of diabetic melioidosis patients in Thailand were prescribed glibenclamide. Recent evidence demonstrates that glibenclamide reduces pro-inflammatory cytokine production by polymorphonuclear neutrophils (PMNs) of diabetic individuals in response to this bacterial infection. However, the mechanisms by which glibenclamide affects cytokine production are unknown. We found that PMNs from glibenclamide-treated diabetic individuals infected with live B. pseudomallei in vitro showed lower free glutathione (GSH) levels compared with those of healthy individuals. Glibenclamide decreased GSH levels and glutathione peroxidase (GPx) of PMNs after exposed to live B. pseudomallei. Moreover, glibenclamide reduced cytokine production and migration capacity of infected PMNs, whereas GSH could restore these functions. Taken together, our data show a link between the effect of glibenclamide on GSH and PMN functions in response to B. pseudomallei that may contribute to the susceptibility of diabetic individuals to B. pseudomallei infection.

Diagnostic Algorithm in the Management of Acute Febrile Abdomen in Patients with Autosomal Dominant Polycystic Kidney Disease

Background

Acute febrile abdomen represents a diagnostic challenge in patients with autosomal dominant polycystic kidney disease (ADPKD). Although criteria have been proposed for cyst infection (CyI) and hemorrhage (CyH), there is a lack of comparative assessments. Furthermore, distinguishing cystic from non-cystic complications remains problematic.

Design

ADPKD patients presenting with abdominal pain and/or fever between 01/2005 and 06/2015 were retrospectively identified in a systematic computerized billing database. CyH was defined as spontaneous intracystic density above 50 Hounsfield units on computed tomography (CT). CyI was definite if confirmed by cyst puncture, and probable if 4 criteria were met: 3-day fever, loin/liver tenderness, C-reactive protein (CRP) plasma levels >50mg/L and no CT evidence for CyH. Other episodes were grouped as inflammation of unknown origin (IUO).

Results

Among a cohort of 173 ADPKD patients, 101 presented with 205 episodes of abdominal pain (n = 172) and/or fever (n = 33). 20 patients experienced 30 CyH, whereas 16 presented 23 episodes of definite (n = 11) or probable (n = 12) CyI. 35 IUO were observed in 31 patients. Clinically, fever was observed in 7% vs. 100% vs. 66% of CyH, CyI and IUO, respectively. Biologically, CRP cut-off at 70 mg/dl showed 92% sensitivity and 81% specificity in CyI diagnosis. Urine or blood cultures remained sterile in >90% of CyH, but were contributive in 53.4% of CyI and IUO, with a 74.2% prevalence for E. coli. Radiologically, ultrasounds, CT and magnetic resonance diagnosed CyI in 2.6%, 20% and 16.7% of cases, respectively. ¹⁸F-FDG positron-emission tomography (PET)/CT was done within a median period of 7 days post antibiotics, and significantly changed patient management in 71.4%.

Conclusions

This retrospective single-center series underscores the usefulness of clinical–fever–and biological–CRP–parameters, but emphasizes the limitations of bacteriological and radiological investigations in cases of acute febrile abdomen in ADPKD patients. ¹⁸F-FDG-PET/CT imaging may be helpful in such condition.