Use of PET-CT in diagnostic workup of periprosthetic infection of hip and knee joints: significance in detecting additional infectious focus.

INTRODUCTION: The diagnosis and management of periprosthetic knee and hip infections as well as the identification and management of possible additional infectious foci is of great importance for successful therapy. This study analyses the importance of 18F deoxyglucose PET-CT (PET-CT) in the identification of additional infectious focus and subsequent impact on management of periprosthetic infection (PPI). MATERIAL AND METHODS: A retrospective analysis of the clinical data and findings in the period from January 2008 to December 2018 was carried out. One hundred and four patients with in-hospital treatment due to PPI of a hip or knee joint were identified and included in this study. All patients underwent a standardized clinical examination and further surgical and antibiotic therapy. The reevaluation of performed PET-CTs was specifically carried out with regard to the local PPI or detection of secondary foci. RESULTS: PET-CT successfully verified the PPI in 84.2% of the patients. A total of 78 possible additional foci were detected in PET-CT in 56 (53.8%) of the examined patients. Predilection sites for possible secondary foci were joints (42.3%), pulmonary (15.4%), ear-nose-throat (15.4%), spine (11.5%), and the musculocutaneous tissues (11.5%). Fifty-four positive PET-CT findings were confirmed clinically with need of additional adequate treatment. CONCLUSION: PET-CT is a valuable diagnostic tool to confirm periprosthetic joint infection. At the same time, the whole-body PET/CT may detect additional foci of infection with impact on subsequent treatment strategy. PET was of special value in detecting infections at distant locations far from the primary infected joint in significant number. These distant infection locations can be potential cause of a re-infection. This clearly reflects the need of their diagnosis.

Cholelithiasis: a frequent complication of artificial heart valve replacement.

The results of this investigation reveal that 39 per cent of patients in a study group of 46 patients with heart valve prostheses had gallstones if they survived 18 months or longer following valve replacement. In contrast, the prevalence of gallstones in a general population of autopsied rheumatic heart disease patients, including those who had been operated for severe valvular heart disease and had not survived for more than one month, was only 12 per cent. These findings suggest that gallstones are a frequent late complication of heart valve replacement.

Clinical experience with the Smeloff-Cutter aortic valve prosthesis: an 8-year follow-up study.

A total of 46 patients who survived aortic valve replacement with the present model Smeloff-Cutter prosthesis between 1968 and 1973 were followed up postoperatively. All patients received oral anticoagulant therapy. The average age at implantation was 44 +/- 13 (mean +/- standard deviation) years; 36 patients were male and 10 were female. The valve damage was caused by rheumatic disease in 19 (41 percent), infective endocarditis in 14 (30 percent), congenital heart disease in 7 (15 percent) and other factors in 6 (13 percent). Late death occurred in eight patients (17 percent). All available patients were followed up until December 1976. During the 8 years of follow-up study, seven patients, including four heroin addicts, had postoperative endocarditis (15 percent); five of the seven had cerebral involvement, possibly from septic emboli. Four patients were reoperated on; three had active endocarditis and one had a high transvalve pressure gradient. The mean follow-up time was 4.9 years per patient. Of the 38 living patients, 33 have functional improvement and are still being followed up. Only one patient had a bland embolism to a systemic artery. No ball variance or other types of material failure have been detected. Although the chronic aspects of valve disease remain after prosthetic valve replacement, the Smeloff-Cutter aortic prosthesis deserves strong consideration when selecting a rigid prosthesis for aortic valve replacement.

Phonoangiography by autocorrelation.

Phonoangiography, as a noninvasive quantitative analysis of arterial bruits, was conducted just prior to standard invasive radiographic angiography in 135 patients. Sound records from 162 carotid arteries were analyzed with a new processing technique employing a high speed analog acoustic analyzer, the autocorrelator. In 18 arteries with carotid stenosis, a correlation coefficient of 0.87 resulted between phonoangiographic diameter predictions and radiographic diameter estimates. Bruit analysis identified two patients with patent lumen diameters, but tortuous carotid vessels. One hundred thirty-three carotid arteries had no bruits that could be analyzed, but angiograms showed no extracranial stenosis. Four arteries from which bruits could not be analyzed were found to be totally occluded. Carotid phonoangiography appears applicable in approximately one of seven patients now requiring angiography of head and neck vessels. When applicable, phonoangiography is significantly correlated with angiographic findings.

In vivo degradation of silicone rubber poppets in prosthetic heart valves.

Dynamic shear modulus G' was measured throughout the volume of three nonvariant silicone rubber poppets which were recovered from aortic prosthetic heart valves that had been implanted for 4 days, 52 days, and 8 years. Similar measurements were obtained for two unused silicone rubber poppets. Although the recovered poppets exhibited no obvious physical evidence of damage, the silicone rubber had undergone in vivo degradation throughout the poppet volume as indicated by decreases in modulus. The measurements also indicate that the poppet surface degrades at a rate faster than the core. Further, comparison with data reported in the literature suggests that the surfaces of variant poppets degrade at a rate faster than the surfaces of nonvariant poppets.