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

Cyst infection is a common complication of autosomal dominant polycystic kidney disease (ADPKD). Diagnosis is challenging with standard imaging techniques. We aimed to evaluate the diagnostic performance of [(18)F]fluorodeoxyglucose positron emission tomography-computed tomography (18-FDG PET-CT) for the diagnosis of cyst infections among ADPKD patients, in comparison with computed tomography (CT) and magnetic resonance imaging (MRI). All APKD patients who underwent 18-FDG PET-CT for suspected cyst infection between 2006 and 2013 in a French teaching hospital were included. Diagnosis of cyst infection was retained a posteriori on an index of clinical suspicion. 18-FDG PET-CT findings were was considered to be positive in cases of cyst wall hypermetabolism. CT or MRI findings were were considered to be positive in cases of cyst wall thickening (and enhancement if contrast medium was injected) and infiltration of the adjacent fat. A control group of ADPKD patients with 18-FDG PET-CT performed for other reasons was included. Thirty-two 18-FDG PET-CT scans were performed in 24 ADPKD patients with suspected cyst infection. A diagnosis of cyst infection was retained in 18 of 32 cases: 14 with positive 18-FDG PET-CT findings, and four false negatives. There were no false positives and no hypermetabolism of cyst walls in nine ADPKD control patients. 18-FDG PET-CT had a sensitivity of 77%, a specificity of 100%, and a negative predictive value of 77%. 18-FDG PET-CT allowed a differential diagnosis in three patients. In contrast, CT had a sensitivity of 7% and a negative predictive value of 35% (p <0.001 vs. 18-FDG PET-CT). Only eight MRI scans were performed. The diagnostic performance of 18-FDG PET-CT is superior to that of CT in cyst infections, for comparable radiation doses and with no injection of nephrotoxic contrast medium, in ADPKD patients.

Survival of patients with ANCA-associated vasculitis on chronic dialysis: data from the French REIN registry from 2002 to 2011.

BACKGROUND: Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) can lead to end-stage renal disease in patients with renal involvement. OBJECTIVE: This study evaluated the survival of AAV patients on chronic dialysis in France. METHODS: Between 2002 and 2011, a total of 425 AAV patients started chronic dialysis and were registered in the Renal Epidemiology and Information Network. We analysed survival censored for renal transplantation, recovery of renal function and loss to follow-up. AAV patients were compared with 794 matched non-AAV patients on chronic dialysis. RESULTS: A total of 166 (39%) patients with microscopic polyangiitis and 259 (61%) patients with granulomatosis with polyangiitis were registered. Within a median follow-up of 23 months, 58 (14%) patients received a renal allograft and 19 (4%) recovered renal function. Median survival on dialysis was 5.35 years (95% CI, 4.4-6.3) and survival rates at 3 months, 1, 3 and 5 years were 96%, 85%, 68% and 53%, respectively. A total of 143 (41%) patients died after a median of 16 months. Causes of death were cardiovascular (29%), infections (20%), malnutrition (13%), malignancies (4%), AAV relapse (2%), miscellaneous (14%) and unknown (18%). Multivariate logistic regression identified three independent risk factors associated with AAV patients' mortality: age (HR = 1.05/year, P < 0.001), peripheral artery disease (HR = 2.62, P = 0.003) and frailty (HR = 2.43, P < 0.001). Survival of AAV patients did not differ from non-AAV controls, but infectious mortality was higher in AAV patients (20% vs. 8%, P < 0.001). CONCLUSION: Survival of AAV patients in chronic dialysis, although poor, was comparable to survival of non-AAV controls on dialysis. There was a similar burden of cardiovascular mortality, but higher infectious mortality.