***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: Aim To assess the extent to which bone marrow scintigraphy ( BMS ) makes the interpretation of  leucocyte scintigraphy ( LS ) easier and improves its diagnostic value . Methods Seventy-three 111In LSs , 99mTc hydroxymethylene diphosphonate bone scintigraphies ( BSs ) and 99mTc sulfur colloid BMSs were performed in 60 patients with suspected infection related to a hip prosthesis or knee prosthesis , either in situ ( + group , n=43 ) or after removal for septic loosening ( −group , n=30 ) . Bacteriological sample s were obtained from all patients . LS was interpreted together with BS ( LS-BS ) or with BMS ( LS-BMS ) by three independent readers . Results The concordance among readers , estimated by the kappa test , was average with LS-BS ( κ/κm coefficients=0.58 , 0.58 and 0.46 , respectively , for the three pairs of readers ) and excellent with LS-BMS ( κ/κm coefficients=1.00 for the three pairs of readers ) . With LS-BS , 64/219 interpretations were equivocal whereas only one was equivocal with LS-BMS . Sensitivity , specificity and accuracy of LS-BMS  were , respectively , 80 % , 94 % and 91 % in the+group , and 33 % , 100 % and 93 % in the−group . Conclusion We conclude that ( 1 ) the interpretation of the results for LS-BMS is very easy , in contrast to LS-BS ; ( 2 ) the diagnostic value of LS-BMS for detecting infected joint prostheses is good ; and ( 3 ) additional data are needed to assess the accuracy of LS-BMS when the prosthesis has been removed Purpose This study aims to assess and compare the value of FDG PET with combined 111In-labeled leukocyte/99mTc-sulfur colloid bone marrow ( WBC/BM ) imaging for diagnosing infection in hip and knee prostheses . Methods In this prospect i ve study , patients with painful hip or knee arthroplasty , who were scheduled to undergo clinical and diagnostic evaluation for prosthesis revision , were included . They have been studied by using FDG PET and WBC/BM scan . This study was institutional review board approved and Health Insurance Portability and Accountability Act compliant . All patients provided written informed consent . Results A total of 134 hip and 87 knee prostheses , suspected of being either infected or noninfectious loosening , were evaluated . All 221 prostheses underwent FDG PET , whereas both  WBC/BM imaging and FDG PET  were performed in 88 prostheses . The initial analysis of data from the WBC/BM images demonstrated somewhat suboptimal results compared with those of FDG PET scans on 88 patients . In addition , some patients were not willing to undergo both procedures and therefore participate in this study . Therefore , a decision was made to eliminate WBC/BM imaging from the procedures for the remainder of this research study . This decision was reached partly because of the significant radiation dose delivered from labeled WBC and safety issues related to preparing these labeled cells . Final diagnosis was based on microbiological examinations of the surgical specimens in 125 prostheses and joint aspirations combined with the clinical follow-up of 6 months or more in 86 prostheses . The sensitivity , specificity , positive predictive value , and negative predictive value of FDG PET  in hip prostheses were 81.8 % , 93.1 % , 79.4 % , and 94.0 % , respectively , and in knee prostheses were 94.7 % , 88.2 % , 69.2 % , and 98.4 % , respectively . The sensitivity , specificity , positive predictive value , and negative predictive value of WBC/BM imaging in hip prostheses were 38.5 % , 95.7 % , 71.4 % , and 84.6 % , respectively , and in knee prostheses were 33.3 % , 88.5 % , 25.0 % , and 92.0 % , respectively . In those cases that underwent both FDG PET and WBC/BM imaging , there was a trend ( P = 0.0625 ) toward a higher sensitivity for FDG PET in hip prostheses , whereas other comparisons did not show any significant differences between the 2 imaging modalities . Conclusions Based on this study , the diagnostic performance of FDG PET scan in detecting infection in painful hip and knee prostheses is optimal for routine clinical application . Considering the complexity and costs of WBC/BM imaging and related safety issues associated with this preparation , FDG PET seems to be an appropriate alternative for assessing these patients PURPOSE To prospect ively determine the accuracy of computed tomography ( CT ) in the detection of  painful infection at the site of hip prosthesis before surgery . MATERIAL S AND METHODS Helical CT examinations of hip prostheses were prospect ively performed before surgery after a st and ard clinical and radiologic examination of 65 patients .  CT scans and conventional radiographs were review ed for periprosthetic bone abnormalities , and CT scans were review ed for periprosthetic soft-tissue abnormalities ( joint distention , fluid-filled bursae , and fluid collection in muscles and perimuscular fat ) . Patients subsequently underwent revision arthroplasty within 1 month , and infection was diagnosed in 12 ( 19 % ) patients . RESULTS Infection was detected clinical ly in 25 % of patients . Periprosthetic bone abnormalities did not allow differentiation of infection from complications not related to sepsis , except for periostitis , with 100 % specificity but only 16 % sensitivity . Soft-tissue findings were accurate for detection of infection , with 100 % sensitivity and 87 % specificity . Fluid collection in muscles and perimuscular fat had a 100 % positive predictive value , and absence of joint distention had a 96 % negative predictive value . CONCLUSION CT is accurate in the diagnosis of painful infection  at the site of a hip prosthesis on the basis of soft-tissue findings , whereas periprosthetic bone abnormalities are not useful Aim To analyse the role played by bone scintigraphy in the diagnosis of infected joint prostheses . Methods The study included 77 patients , aged 32–77 years , in whom infection of a joint prosthesis ( 48 hip , 29 knee ) was suspected . In all patients the following examinations were performed consecutively : a two-phase 99mTc methylene diphosphonate ( 99mTc-MDP ) bone scan , a 99mTc hexamethylproplyene amine oxime ( 99mTc-HMPAO ) labelled white blood cell ( WBC ) scan , and a 99mTc microcolloid bone marrow ( BM ) scan . The minimum interval between examinations was 48 h. The diagnoses were based on data obtained from bacteriological cultures . Results The bone scan was positive in all patients and 28 of them had an infection ( sensitivity 100 % , specificity 0 % ) . The  WBC scan was positive in 61 patients but only 27 had an infection . The WBC scan was negative in 16 patients , and the possibility of infection was discarded in 15 of these cases ( sensitivity 96 % , specificity 30 % ) . The results of the bone marrow scan were not compatible with those of the WBC scan  ( suggestive of infection ) in 27 patients : 26 of them had prosthesis infection . The results of both examinations were compatible in the other 34 patients and the possibility of infection was discarded in 33 of these patients ( sensitivity 92.8 % , specificity 98 % ) . The addition of a BM scan to a WBC scan decreased the sensitivity from 96 % to 92.8 % but increased specificity from 30 % to 98 % . The addition of a bone scan to this dual combination did not alter the results . Conclusions When infection of a prosthesis is suspected the diagnostic procedure should start with a WBC scan followed , if positive , by a BM scan . This procedure reduces the cost , the time required for a diagnosis , and the dose of radiation received by the patient Ten per cent of patients with hip replacement will eventually complain of significant pain after surgery , often requiring a revision arthroplasty . The majority of these patients experience aseptic loosening rather than infection . Despite significant advances made in diagnostic imaging , distinguishing infection from aseptic loosening remains a significant challenge . Imaging using fluorodeoxyglucose ( FDG ) positron emission tomography ( PET ) has been reported to have excellent sensitivity in detecting infections associated with hip prostheses . However , in some studies , a high rate of false positive results has been reported , especially when increased tracer uptake adjacent to the prosthesis ( which is not surrounded by bone ) is used as the sole criterion for diagnosing infection . The objective of this investigation was to determine the optimal criteria for diagnosing periprosthetic infection , thereby avoiding false positive results in this setting . A total of 41 total hip arthroplasties from 32 patients and for whom complete clinical follow-up was available were included in this analysis . The location and intensity of FDG uptake were determined for each scan . Final diagnosis was made by microbiology , histopathology , surgical findings and clinical follow-up . Patients who did not undergo surgery were followed up to at least 9 months . Twelve patients were proven eventually to have periprosthetic infection . Images from 11 of these patients displayed increased tracer uptake along the interface between bone and prosthesis . The intensity of the increased tracer uptake varied from mild to moderate , with st and ardized uptake values less than 2 . In contrast , images from uninfected , loose hip prostheses revealed very intense uptake around the head or neck of the prosthesis with st and ardized uptake values as high as 7 . It is concluded that the intensity of increased FDG uptake is less important than the location of increased FDG uptake when FDG PET is used to diagnose periprosthetic infection in patients with hip arthroplasty . Using increased uptake as the sole criterion for diagnosing infection will result in false positive results in this setting To determine the value of immunoscintigraphy ( IS ) with antigranulocyte monoclonal antibodies ( Mab ) in the diagnosis of subacute or chronic infection of hip prostheses , we prospect ively studied 57 patients ( 23 women and 34 men ; age 29–92 years , mean 72.7 years ) sent to our institution in the past 6 years for clinical suspicion of septic loosening of a hip prosthesis . Nineteen patients had bilateral prostheses and one of them was studied twice . A total of 78 prostheses were examined . All patients had three-phase bone scans followed by IS with technetium-99 m antigranulocyte Mab BW 250/183 . Intervals between bone scans and IS varied from 2 days to 4 weeks . Final diagnosis was assessed by culture in 48 cases ( articular puncture or intraoperative sampling ) and by clinical follow-up of at least 8 months in 30 cases . Twelve prostheses were considered septic and 66 non-septic . The overall sensitivity and specificity were 92 % and 64 % respectively for bone scans , 67 % and 75 % for IS and 67 % and 84 % for both modalities together . In three cases , IS was doubtful and the final clinical diagnosis was negative for infection . False-positive results were observed in the presence of massive loosening of the prosthesis or in association with metaplastic peri-articular bone formation . In three of the four false-negative results , infection was proven only after enrichment of the culture , and the bacterium wasStaphylococcus epidermidis . In 12/33 ( 36 % ) positive bone scans IS allowed the diagnosis of infection to be excluded . Overall accuracy of both modalities together was 81 % and the negative predictive value was 93 % , which compares favourably with the results reported for other non-invasive methods We compared the accuracy of fluorine-18 labelled 2-fluoro-2-deoxy-d-glucose positron emission tomography ( 18FDG PET ) with that of technetium-99 m hexamethylpropylene amine oxime leucocyte scintigraphy ( LS ) in the detection of infected hip prosthesis . Seventeen patients with a hip prosthesis suspected for infection were prospect ively included and underwent 99mTc-methylene diphosphonate bone scintigraphy ( BS ) , LS and an 18FDG-PET scan within a 2-week period . Seven volunteers with ten asymptomatic hip prostheses were used as a control group and underwent BS and an 18FDG-PET scan . Bacteriology of sample s obtained by surgery or by needle aspiration and /or clinical follow-up for up to 6 months were used as the gold st and ard . Planar images of BS and LS ( 4 and 24 h p.i . ) were acquired , followed by single-photon emission tomography ( SPET ) LS images ( after 4 h ) . These images were scored as positive or negative by two experienced readers . The 18FDG-PET scans of the patients were compared with the tracer distribution pattern in the asymptomatic control group and with 
    Output:
    
Of the currently used imaging techniques , leukocyte scintigraphy has satisfactory accuracy in confirming or excluding periprosthetic hip infection .
Although not significantly different , combined leukocyte and bone marrow scintigraphy was the most specific imaging technique .
FDG PET has an appropriate accuracy in confirming or excluding periprosthetic hip infection , but may not yet be the preferred imaging modality because of limited availability and relatively higher cost .