Leukocyte Scintigraphy Research Articles

Nuclear Imaging for Classic Fever of Unknown Origin: Meta-Analysis.

We searched PubMed, Scopus, and other databases through October 31, 2015, to identify studies reporting on the diagnostic accuracy or impact on diagnosis and management decisions of 18F-FDG PET alone or integrated with CT (18F-FDG PET/CT), gallium scintigraphy, or leukocyte scintigraphy. Two reviewers extracted data. We quantitatively synthesized test performance and diagnostic yield and descriptively analyzed evidence about the impact on management decisions. We included 42 studies with 2,058 patients. Studies were heterogeneous and had methodologic limitations. Diagnostic yield was higher in studies with higher prevalence of neoplasms and infections. Nonneoplastic causes, such as adult-onset Still's disease and polymyalgia rheumatica, were less successfully localized. Indirect evidence suggested that 18F-FDG PET/CT had the best test performance and diagnostic yield among the 4 imaging tests; summary sensitivity was 0.86 (95% confidence interval [CI], 0.81-0.90), specificity 0.52 (95% CI, 0.36-0.67), and diagnostic yield 0.58 (95% CI, 0.51-0.64). Evidence on direct comparisons of alternative imaging modalities or on the impact of tests on management decisions was limited. Nuclear imaging tests, particularly 18F-FDG PET/CT, can be useful in identifying the source of fever in patients with classic FUO. The contribution of nuclear imaging may be limited in clinical settings in which infective and neoplastic causes are less common. Studies using standardized diagnostic algorithms are needed to determine the optimal timing for testing and to assess the impact of tests on management decisions and patient-relevant outcomes.

Deleterious effects of 28-day oral co-administration of first-line anti-TB drugs on spleen, blood and bone marrow chromosomes in normal rat

Context: Isoniazid, rifampicin and pyrazinamide are most reliable and cost-effective remedy for tuberculosis treatment and prophylaxis among first-line anti-tuberculosis (TB) drugs and have a pronounced tendency to cause adverse drug reactions. Hepatotoxicity is well-studied side effect of these drugs but their effects on other organs like spleen and blood are still needed to be explored. Objective: To explore the probable outcome of co-administration these three major antitubercular drugs (ATDs), rifampicin, isoniazid and pyrazinamide on spleen, blood and bone marrow. Materials and methods: Different parameters were evaluated like lipid peroxidation, glutathione (GSH) and protein content in spleen by spectrophotometric evaluation, hematological evaluation by determining total hemoglobin, total leukocyte count, differential leukocyte count and scanning electron microscopy studies in blood, genotoxicity studied by bone marrow chromosomal analysis and DNA fragmentation. The female rats n = 12 (150–200 g) were grouped as control group orally given saline and toxicant group given INH (30.85 mg/kg b.wt.) + RIF (61.7 mg/kg b.wt.) + PZA (132.65 mg/kg b.wt.) dosage extrapolated from dose that is used in human for 28 d once daily. Results: After 28 d-oral co-administration of anti-TB drugs (INH (30.85 mg/kg b.wt.) + RIF (61.7 mg/kg b.wt.) + PZA (132.65 mg/kg b.wt.)), it was revealed that there were an increase thiobarbituric acid reactive substances, decrease in GSH and protein contents in spleen. Marked changes in hematological parameters, DNA fragmentation and chromosomes were also observed. Conclusion: This can be concluded from this work that co-administration of first-line ATDs is toxic to spleen and blood also these drugs can cause damage at genetic level.

Performance of Common Disease Activity Markers as a Reflection of Inflammatory Burden in Ulcerative Colitis.

The inflammatory burden influences therapeutic decisions in patients with ulcerative colitis (UC). We aimed to study which commonly used markers of disease activity correlate best with inflammatory burden in patients with UC using leukocyte scintigraphy (single-photon emission computed tomography [SPECT-CT]) as the gold standard. Patients with different severity of UC underwent colonoscopy with biopsies and leukocyte SPECT-CT scintigraphy. Serum C-reactive protein (CRP), fecal calprotectin, and clinical questionnaires were collected. The maximum uptake of technetium-labeled leukocytes was calculated as a SPECT score for each colon segment and a summed activity score for 5 colonic segments combined. Thirty patients with UC were included; 14 of 30 (47%) had left-sided colitis, and 16 of 30 (53%) had pancolitis. One patient (3%) had inactive UC, 5 of 30 (17%) had mild, 11 of 30 (37%) had moderate, and 13 of 30 (43%) had severe disease activity based on the endoscopic Mayo score. The endoscopic Mayo score correlated better with the SPECT score than with the ulcerative colitis endoscopic index of severity (UCEIS) (r = 0.50; P < 0.01 and r = 0.32; P = 0.08, respectively). The Geboes UC histologic score correlated equally well as the Mayo score (r = 0.50; P < 0.01). We found a significant correlation between scintigraphy and fecal calprotectin (r = 0.44; P = 0.02) but not with serum CRP (r = 0.25; P = 0.18). Fecal calprotectin reflected inflammatory burden significantly better in left-sided colitis (r = 0.80; P = 0.001) than in pancolitis (r = 0.22; P = 0.41). The inflammatory burden in patients with UC, measured by SPECT-CT, is better reflected by the endoscopic Mayo score and the Geboes histologic score than by the UCEIS. Fecal calprotectin is a more accurate inflammatory marker than CRP, predominantly in patients with left-sided colitis. This study was approved by the Ethics Committee Review at October 22, 2012 and, in accordance with Dutch legislation, prospectively registered at the CCMO (Dutch central commission for human research) https://www.toetsingonline.nl with NL39801.018.12.

Endovascular repair of thoracoabdominal aortic aneurysm using the off-the-shelf multibranched t-Branch stent graft

Endovascular repair has been increasingly used to treat thoracoabdominal aortic aneurysms using patient-specific or off-the-shelf fenestrated and branched stent grafts. Device customization limits the application of patient-specific devices in patients who need urgent or emergency repair because of ruptured or large, rapidly expanding aneurysms. For these patients, an off-the-shelf multibranched stent graft, the t-Branch stent graft (Cook Medical, Bjaeverskov, Denmark) hasbeen developed based on the relative predictability of visceral vessel anatomy, allowing incorporation and intraoperative customization of target vessels with four down-going directional branches. We used the t-Branch stent graft in a 66-year-old woman with a rapidly enlarging type III thoracoabdominal aortic aneurysm. Completion angiography and follow-up computed tomography angiography demonstrated successful exclusion of the aneurysm sac, patent target vessels, and nearly complete sac shrinkage at the 12-month follow-up.

Nuclear medicine imaging of posttraumatic osteomyelitis.

IntroductionEarly recognition of a possible infection and therefore a prompt and accurate diagnostic strategy is essential for a successful treatment of posttraumatic osteomyelitis (PTO). However, at this moment there is no single routine test available that can detect osteomyelitis beyond doubt and the performed diagnostic tests mostly depend on personal experience, available techniques and financial aspects. Nuclear medicine techniques focus on imaging pathophysiological changes which usually precede anatomical changes. Together with recent development in hybrid camera systems, leading to better spatial resolution and quantification possibilities, this provides new opportunities and possibilities for nuclear medicine modalities to play an important role in diagnosing PTO.AimIn this overview paper the techniques and available literature results for PTO are discussed for the three most commonly used nuclear medicine techniques: the three phase bone scan (with SPECT-CT), white blood cell scintigraphy (also called leukocyte scan) with SPECT-CT and 18F-fluorodeoxyglucose (FDG)-PET/CT. Emphasis is on how these techniques are able to answer the diagnostic questions from the clinicians (trauma and orthopaedic surgeons) and which technique should be used to answer a specific question. Furthermore, three illustrative cases from clinical practice are described.

IWGDF guidance on the diagnosis and management of foot infections in persons with diabetes.

RecommendationsClassification/diagnosis Diabetic foot infection must be diagnosed clinically, based on the presence of local or systemic signs or symptoms of inflammation (strong; low). Assess the severity of any diabetic foot infection using the Infectious Diseases Society of America/International Working Group on the Diabetic Foot classification scheme (strong; moderate). Osteomyelitis For an infected open wound, perform a probe‐to‐bone test; in a patient at low risk for osteomyelitis, a negative test largely rules out the diagnosis, while in a high‐risk patient, a positive test is largely diagnostic (strong; high). Markedly elevated serum inflammatory markers, especially erythrocyte sedimentation rate, are suggestive of osteomyelitis in suspected cases (weak; moderate). A definite diagnosis of bone infection usually requires positive results on microbiological (and, optimally, histological) examinations of an aseptically obtained bone sample, but this is usually required only when the diagnosis is in doubt or determining the causative pathogen's antibiotic susceptibility is crucial (strong; moderate). A probable diagnosis of bone infection is reasonable if there are positive results on a combination of diagnostic tests, such as probe‐to‐bone, serum inflammatory markers, plain X‐ray, magnetic resonance imaging (MRI) or radionuclide scanning (strong; weak). Avoid using results of soft tissue or sinus tract specimens for selecting antibiotic therapy for osteomyelitis as they do not accurately reflect bone culture results (strong; moderate). Obtain plain X‐rays of the foot in all cases of non‐superficial diabetic foot infection (strong; low). Use MRI when an advanced imaging test is needed for diagnosing diabetic foot osteomyelitis (strong; moderate). When MRI is not available or contraindicated, consider a white blood cell‐labelled radionuclide scan, or possibly single‐photon emission computed tomography (CT) and CT (SPECT/CT) or fluorine‐18‐fluorodeoxyglucose positron emission tomography/CT scans (weak; moderate). Assessing severity At initial evaluation of any infected foot, obtain vital signs and appropriate blood tests, debride the wound and probe and assess the depth and extent of the infection to establish its severity (strong; moderate). At initial evaluation, assess arterial perfusion and decide whether and when further vascular assessment or revascularization is needed (strong; low). Microbiological considerations Obtain cultures, preferably of a tissue specimen rather than a swab, of infected wounds to determine the causative microorganisms and their antibiotic sensitivity (strong; high). Do not obtain repeat cultures unless the patient is not clinically responding to treatment, or occasionally for infection control surveillance of resistant pathogens (strong; low). Send collected specimens to the microbiology laboratory promptly, in sterile transport containers, accompanied by clinical information on the type of specimen and location of the wound (strong; low). Surgical treatment Consult a surgical specialist in selected cases of moderate, and all cases of severe, diabetic foot infection (weak; low). Perform urgent surgical interventions in cases of deep abscesses, compartment syndrome and virtually all necrotizing soft tissue infections (strong; low). Consider surgical intervention in cases of osteomyelitis accompanied by spreading soft tissue infection, destroyed soft tissue envelope, progressive bone destruction on X‐ray or bone protruding through the ulcer (strong; low). Antimicrobial therapy While virtually all clinically infected diabetic foot wounds require antimicrobial therapy, do not treat clinically uninfected wounds with antimicrobial therapy (Strong; Low) Select specific antibiotic agents for treatment based on the likely or proven causative pathogens, their antibiotic susceptibilities, the clinical severity of the infection, evidence of efficacy of the agent for diabetic foot infection and costs (strong; moderate). A course of antibiotic therapy of 1–2 weeks is usually adequate for most mild and moderate infections (strong; high). Administer parenteral therapy initially for most severe infections and some moderate infections, with a switch to oral therapy when the infection is responding (strong; low). Do not select a specific type of dressing for a diabetic foot infection with the aim of preventing an infection or improving its outcome (strong; high). For diabetic foot osteomyelitis, we recommend 6 weeks of antibiotic therapy for patients who do not undergo resection of infected bone and no more than a week of antibiotic treatment if all infected bone is resected (strong; moderate). We suggest not using any adjunctive treatments for diabetic foot infection (weak; low). When treating a diabetic foot infection, assess for use of traditional remedies and previous antibiotic use and consider local bacterial pathogens and their susceptibility profile (strong; low).

A novel approach of 67-Gallium-citrate three-phase bone scan to diagnose bone infection: A report of three cases.

Objectives:67-Gallium-citrate three-phase bone scan (Ga-TPBS), a new approach for the diagnosis of bone infection is evaluated. The interpretation of TPBS is based on the normal physiological vascular endothelial-related response noted in infection.Materials and Methods:Three cases of suspected bone infection as determined by clinical, laboratory, and radiological examinations were further subjected to conventional technetium-99m-TPBS (Tc-99m-TPBS) and Ga-TPBS. Nuclear scan diagnosis of bone infection was made by the presence of generalized vasodilatation with increased capillary permeability noted on the flow and the pool phase of the TPBS and the comparative evaluation of the 4 h delayed Tc-TPBS and 24–48 h delayed Ga-TPBS. Diagnosis of bone infection was confirmed in all three cases on histopathologcal examination of the surgically excised tissues.Results:The data clearly indicated that all three cases of bone infection (osteomyelitis) had generalized massive flow and pool pattern. Infection could be diagnosed only on the Ga-TPBS by noting generalized vasodilatation with increased capillary permeability on the flow and the pool phase with focal retention of the radiotracer on the delayed scan.Conclusions:By incorporating the concept of vascular endothelial-related response causing massive vasodilatation in infection, the interpretation of the Ga-TPBS can be more précised as it is based on the normal physiology. In comparison to two Tc-99m scans (white blood cell scan + bone marrow scan), a single Ga-TPBS is also cost-effective and compliance friendly. Larger, comparative, and statistically unbiased studies are needed.

Edwardsiella tarda Endocarditis Confirmed by Indium-111 White Blood Cell Scan: An Unusual Pathogen and Diagnostic Modality.

Edwardsiella tarda is a freshwater marine member of the family Enterobacteriaceae which often colonizes fish, lizards, snakes, and turtles but is an infrequent human pathogen. Indium-111- (111In-) labeled white blood cell (WBC) scintigraphy is an imaging modality which has a wide range of reported sensitivity and specificity (from 60 to 100% and from 68 to 92%, resp.) for diagnosing acute and chronic infection. We describe a case of suspected E. tarda prosthetic aortic valve and mitral valve endocarditis with probable vegetations and new mitral regurgitation on transthoracic and transesophageal echocardiograms which was supported with the use of 111In-labeled WBC scintigraphy.

Liver Abscess; Uncommon Complication Following Renal Transplantation: Case Report with Review of Literatures

Intra-abdominal and biliary infections are significant cause of morbidity and mortality for the transplant recipients, specifically in the early post-operative period, reflecting substantial immunosuppression. In renal transplant recipients, there is no reported increased risk for pyogenic liver abscess as compared to general population. The diagnosis of hepatic abscess in a transplant recipient can be challenging since presentation could be atypical and the signs and symptoms might be insidious and subtle. If a hepatic abscess is missed and left untreated, it is potentially lethal; hence, an early diagnosis and timely initiation of appropriate therapy is of utmost importance, to improve patient outcomes. We present a case record of a 29 year old male patient who received a living unrelated renal transplant in 2007. He presented 8 years post-transplant with a fever of unknown origin; clinical and laboratory tests did not provide any clue to the diagnosis. However, labeled white cell scan (Leukoscan) followed by abdominal ultrasound scan (USS) revealed an unexpected finding of a large liver abscess (5.57 × 6.05 cm). He responded well to a course of antibiotics including metronidazole therapy besides requiring percutaneous abscess drainage.

Fever of Unkown Origin as a Sole Manifestation of Pancreas Allograft Rejection

Fever in a transplant recipient is almost always suspicious of an infectious etiology. We present a patient with simultaneous pancreas and kidney transplant who had persistent high grade fever for a month which could only be attributed to pancreas allograft rejection. A 56 year old white man with history of simultaneous kidney-pancreas transplant (SPK) a month prior presented with fever of unknown etiology. Patient denied any sick contacts or any localizing signs and symptoms. On examination, his temperature was 102.1 °F. Rest of the examination was unremarkable. His immunosuppression consisted of tacrolimus 3 mg twice daily, mycophenolate 1000 mg twice daily, and Prednisone 10 mg daily. Initial laboratory work up showed serum creatinine 1.8 mg/dl (Baseline serum Cr 1.8-2.0 mg/dl), tacrolimus level 14 ng/dl, serum amylase 82, serum lipase 67, glucose 89 mg/dl, and normal urine analysis. In addition, blood culture, urine culture, and serum cytomegalovirus, Epstein Barr virus and BK virus PCR were negative. Chest X ray and CT scan of abdomen and pelvis did not show any significant pathology. Patient's fever continued unabated in the range of 100-103°F daily for a month despite empirical antibiotic therapy while cultures remained negative. Rest of the negative work-up included an echocardiogram, kidney ultrasound with kidney biopsy, cerebrospinal fluid analysis, tagged white blood cell scan, upper and lower gastrointestinal scopes with biopsy of gastrointestinal mucosa for any viral inclusions. Nuclear PET scan showed increased activity in the pancreas transplant. Pancreas allograft biopsy confirmed pancreas allograft rejection although serum amylase and lipase were normal at the time of biopsy. Fever disappeared after initiation of steroids and has not recurred since discharge from the hospital 3 months ago. In conclusion, pancreas allograft rejection may present as fever of unknown etiology in a pancreas transplant recipient. Serum amylase and lipase may not be the reliable markers of pancreatic transplant rejection.

Screening with angiographic images prior to (99m)Tc-HMPAO labelled leukocyte scintigraphy in the diagnosis of periprosthetic infection

To evaluate the impact of the angioscintigrapy of the three phase bone scan as screening method to rule out infection of the hip and knee prosthesis prior to performing the (99m)Tc-HMPAO leukocyte scintigraphy. A total of 120 (70 women, 50 men; mean age 71±11years) with clinical suspicion of hip (n=63) or knee (n=57) infection of the prosthesis and clinical suspicion of infection were evaluated prospectively. All patients underwent three-phase bone scan (angioscintigraphy, vascular and bone phase) and (99m)Tc-HMPAO-labelled white blood cell scintigraphy. Final diagnosis of infection was made by microbiological documentation or clinical follow-up for at least 12months. Eighteen out of 120 patients were diagnosed of infection of hip prosthesis (n=10) or knee prosthesis (n=8). The angioscintigraphy was positive in 15/18 infected cases and in 21/102 of the non-infected cases with a sensitivity of 83%, specificity of 79% and negative predictive value of 97%. Sensitivity and specificity of (99m)Tc-HMPAO leukocyte scintigraphy were 72% and 95%, respectively. If the leukocyte labeled scintigraphies had been used exclusively for patients with positive angioscintigraphy, this would have saved up to 70% of the (99m)Tc-HMPAO leukocyte scintigraphies performed. There were no cases of infection with positive labeled leukocyte scintigraphy and negative angioscintigraphy. Angioscintigraphy (blood flow phase of bone scan) is a useful technique for screening for hip and knee joint prosthesis infection, significantly reducing the need for (99m)Tc-HMPAO leukocyte scintigraphy without affecting the sensitivity of the technique.

Screening with angiographic images prior to 99mTc-HMPAO labelled leukocyte scintigraphy in the diagnosis of periprosthetic infection

AimTo evaluate the impact of the angioscintigrapy of the three phase bone scan as screening method to rule out infection of the hip and knee prosthesis prior to performing the 99mTc-HMPAO leukocyte scintigraphy. Material and methodsA total of 120 (70 women, 50 men; mean age 71±11years) with clinical suspicion of hip (n=63) or knee (n=57) infection of the prosthesis and clinical suspicion of infection were evaluated prospectively. All patients underwent three-phase bone scan (angioscintigraphy, vascular and bone phase) and 99mTc-HMPAO-labeled white blood cell scintigraphy. Final diagnosis of infection was made by microbiological documentation or clinical follow-up for at least 12 months. ResultsEighteen out of 120 patients were diagnosed of infection of hip prosthesis (n=10) or knee prosthesis (n=8). The angioscintigraphy was positive in 15/18 infected cases and in 21/102 of the non-infected cases with a sensitivity of 83%, specificity of 79% and negative predictive value of 97%. Sensitivity and specificity of 99mTc-HMPAO leukocyte scintigraphy were 72% and 95%, respectively. If the leukocyte labeled scintigraphies had been used exclusively for patients with positive angioscintigraphy, this would have saved up to 70% of the 99mTc-HMPAO leukocyte scintigraphies performed. There were no cases of infection with positive labeled leukocyte scintigraphy and negative angioscintigraphy. ConclusionAngioscintigraphy (blood flow phase of bone scan) is a useful technique for screening for hip and knee joint prosthesis infection, significantly reducing the need for 99mTc-HMPAO leukocyte scintigraphy without affecting the sensitivity of the technique.

The use of nuclear imaging for the diagnosis of periprosthetic infection after knee and hip arthroplasties.

Periprosthetic infection and aseptic prosthesis loosening remain the most common and serious complications of total hip arthroplasty and total knee arthroplasty. The differentiation of septic from aseptic prosthetic loosening is of great importance because the treatment of the two conditions is vastly different. Anatomical imaging procedures such as conventional radiography, computed tomography, or MRI are unable to differentiate septic and aseptic loosening, mainly because of hardware-induced artifacts. Nuclear imaging, however, reflects functional rather than anatomical changes and is not hampered by the presence of a metallic prosthesis. The commonly used nuclear imaging techniques include triple-phase bone scintigraphy, 67Ga, leukocyte scintigraphy, leukocyte/bone marrow scintigraphy, monoclonal antibodies/antibody fragments, radiolabeled ciprofloxacin, antimicrobial peptides, etc. Besides infection detection, single-photon emission computed tomography (SPECT) and PET with computed tomography (SPECT/CT and PET/CT) provide additional information on the location of the infection foci, which is clinically important for surgeons to select the most appropriate treatment and guide the intraoperative clearance of the infection foci. The current review will describe the working mechanism, clinical practice, and pros and cons of these techniques in the evaluation of periprosthetic infection.

Osteomyelitis: an overview of imaging modalities.

Diagnosis, early intervention, and treatment of patients who have an infection are the basic foundations of patient care. Early, appropriate interventions are associated with decreased patient morbidity and mortality. Diagnostic procedures with clinical information and laboratory results are integral in the assessment of inflammatory diseases and the prevention of sepsis. Some of the imaging modalities currently used for the assessment of inflammation include computed tomography, plain radiography, positron emission tomography, technetium Tc 99m bone scintigraphy, magnetic resonance imaging, and leukocyte scintigraphy. In the case of patients who exhibit signs of osteomyelitis, it is necessary to understand that acute and chronic conditions are not based on the duration of the disease but on the histopathologic features of the disease. Although several imaging modalities are considered appropriate, there is not one singular procedure that is considered ideal. Rather, it is a combination of procedures and various other clinical factors. This article addresses some of the advantages and disadvantages of the modalities, with a focus on molecular imaging and the assessment of osteomyelitis.

Evaluation of Pulmonary Infection in Rabbits by Tc-99m Hmpao Labeled Leukocyte Scintigraphy

Evaluation of Pulmonary Infection in Rabbits by Tc-99m Hmpao Labeled Leukocyte Scintigraphy

Evaluation of Bone or Soft Tissue Infection with Tc-99m Hmpao White Blood Cell Scintigraphy: Semiquantitative Method

Objective: Aim the aim of this study was to investigate semiquantitatively the diagnostic performance of Tc-99m hexamethypropylene amine oxime labeled white blood cell (Tc-99m HMPAO-WBC) scintigraphy in patients with suspected bone or soft tissue infections. Methods: Material and Method twenty one patients who applied to Nuclear Medicine Departmant (for suspected prosthesis infection, diabetic foot, bone infection, graft infection) were evaluated retrospectively. Tc-99m HMPAO WBC scintigraphy imaging were performed to all patients. Planar images were taken 1., 2., and 4. hours after injecting the labeled leukocytes. Evaluation of infection with Tc-99m HMPAO WBC scintigraphy was done semiquantitatively. Relative uptake was determined by setting the region of interest (ROI) of lesion area on the anterior view. Rectangular ROI was set on the against limb (nonlesion). The ratio of the average pixel count in the lesion (L) to that in the non-lesion (NL) (L/NL ratio) was calculated at 1., 2., and 4. hours images. Final diagnosis was based on histopathology, microbiologic assays, or clinical and imaging follow-up. Results: 0.55 and 1.55±0.74, 1.42±0.55, 1.40±0.55 in positive and control groups, respectively. Positive group revealed a statistically significant increase L/NL values in the data 3 hours images (p=0.002). However, no statistically significant was found between L/NL values in 3 hours imaging data in control group (p=0.223). All the data in the positive group found Zehra Pinar Koc1, Yasemin Bulut2, Sinan Canpolat3, Ayhan Uysal4, Mehmet Sarac5 1Firat University Faculty of Medicine, Department of Nuclear Medicine, Elazig, Turkey 2Firat University Faculty of Medicine, Department of Clinic Microbiology, Elazig, Turkey 3Firat University Faculty of Medicine, Department of Phsiology, Elazig, Turkey 4Firat University Faculty of Medicine, Department of Cardiovascular Surgery, Elazig, Turkey 5Firat University Faculty of Medicine, Department of Pediatric Surgery, Elazig, Turkey Evaluation of Pulmonary Infection in Rabbits by Tc-99m Hmpao Labeled Leukocyte Scintigraphy

Accuracy of Radioactively Labeled Autologous Leukocytes in Patients with Infected Prosthetic Joints

Objective: A serious complication of joint replacement surgery is infection, which results in prolonged invalidity due to decrease in joint function and hospitalization, often resulting in removal and subsequent re-implantation after lengthy antibiotic therapy. Labeled leukocyte scintigraphy (LS) is considered a valuable tool in preoperative diagnosis of prosthetic joint infections. The aim of this study was to examine imaging of in vitro radioactively labeled autologous leukocytes and bone marrow scans in their accuracy and reliability in detecting infection in patients with prosthetic joints. Furthermore, inflammation markers CRP and WBC count were analyzed for their accuracy in detecting prosthetic joint infection. Methods: This single center study included all patients suspected of having prosthetic joint infections between January and September 2013 at the Vienna General Hospital. A total of 45 mL blood was drawn from a peripheral vein and leukocytes were radioactively labeled with Tc-99m-HMPAO according to protocol. The labeled leukocytes were then re-injected into a peripheral vein. A whole body scintigraphy and local images were recorded with a double-headed gamma camera four hours after re-injection. Additional local images were taken taken approximately 24 hours following re-injection. In the case of positive LS, bone marrow scintigraphy was conducted 48 hours after re-injection. Local images were recorded 30 minutes after injection of 370 MBq Tc-99m-nanocolloid. Results: This study included a total of 50 patients. All the patients underwent subsequent bacterial and histological testing via joint aspiration or operation of the joint. The most common joint investigated was knee (27), followed by hip (9), shoulder (2), and elbow (1). Other cases involved the complete femur (6), tibia (2), leg (2), and foot (1). Pathogens isolated from the joints included Staphylococcus epidermidis and Candida albicans. The sensitivity of LS was 63%, specificity 90%, PPV 56% and NPV 93%. Overall accuracy was calculated to be 86%. Pre-diagnostic testing with CRP and WBC was conducted in 43 patients. Mean CRP was 3,9 mg/dl. Thirty-one patients had a CRP-level higher and 12 patients lower than the cut-off. The sensitivity was 57%, specificity 28%, PPV 13%, NPV 77% and accuracy 33%. Lastly, only 3 patients had WBC counts higher than the cut-off. WBC count had a sensitivity of 0%, specificity 92%, PPV 0%, NPV 88% and overall accuracy 82%. Conclusion: While this study showed that CRP and WBC are not accurate pre-diagnostic markers for prosthetic joint infection, it was able to demonstrate that Tc-99m-HMPAO labeled autologous leukocytes in patients presenting with symptoms of prosthetic joint infection is accurate. LS is a feasible imaging method in patients with infection of prosthetic joints and may

0079: Respective performances of FDG-PET and radiolabeled leukocyte scintigraphy for the diagnostic of prosthetic valve endocarditis

The incremental diagnostic value of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) and radiolabeled leukocyte scintigraphy (LS) has already been reported in infective endocarditis (IE) patients. The aim of this study was to compare the respective performances of FDG-PET and LS for the diagnosis of prosthetic valve (PVE)-IE in 39 patients. FDG-PET and LS were performed in 39 consecutive patients admitted for a clinical suspicion of PVE and inconclusive echocardiography who underwent both FDG-PET and LS. FDG-PET and LS were analysed separately and retrospectively by experienced physicians blinded to the results of the other imaging technique and to patient’s outcome. Final Duke-Li IE classification was performed after a 3-month follow-up period. Out of the 39 patients, 15 patients were classified after a 3-month follow-up period as definite IE, 3 as possible IE and 21 as excluded IE. Average time interval between FDG-PET and LS acquisitions was 7±7 days. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 93%, 71%, 70%, 94% and 81% for FDG-PET and 60%, 100%, 100%, 78% and 83% for LS, respectively. Discrepancies between the results of FDG-PET and LS occurred in 12 patients (31%). In patients with definite IE, 5 were identified with true positive FDG-PET but false negative LS. Out of these 5 patients, 3 presented non-pyogenic microorganism IE (Coxiella or Candida). In patients with excluded endocarditis, 6 patients were identified with true negative LS but false positive FDG-PET. These 6 patients had been imaged in the first two months following the last cardiac surgery. FDG-PET offers a high sensitivity for the detection of active infection in patients with a suspicion of PVE. LS offers a higher specificity than FDG-PET for IE diagnosis and should be considered in case of inconclusive FDG-PET findings or in the first two months after cardiac surgery.

Predictors of Diagnostic Efficacy of Tagged White Blood Cell Scans in the Evaluation of Occult Infection

Predictors of Diagnostic Efficacy of Tagged White Blood Cell Scans in the Evaluation of Occult Infection

Clinical utility of indium 111-labeled white blood cell scintigraphy for evaluation of suspected infection.

We sought to characterize the clinical utility of indium 111 ((111)In)-labeled white blood cell (WBC) scans by indication, to identify patient populations who might benefit most from this imaging modality. Medical records for all patients who underwent (111)In-labeled WBC scans at our tertiary referral center from 2005 to 2011 were reviewed. Scan indication, results, and final diagnosis were assessed independently by 2 infectious disease physicians. Reviewers also categorized the clinical utility of each scan as helpful vs not helpful with diagnosis and/or management according to prespecified criteria. Cases for which clinical utility could not be determined were excluded from the utility assessment. One hundred thirty-seven scans were included in this analysis; clinical utility could be determined in 132 (96%) cases. The annual number of scans decreased throughout the study period, from 26 in 2005 to 13 in 2011. Forty-one (30%) scans were positive, and 85 (62%) patients were ultimately determined to have an infection. Of the evaluable scans, 63 (48%) scans were deemed clinically useful. Clinical utility varied by scan indication: (111)In-labeled WBC scans were more helpful for indications of osteomyelitis (35/50, 70% useful) or vascular access infection (10/15, 67% useful), and less helpful for evaluation of fever of unknown origin (12/35, 34% useful). (111)In-labeled WBC scans were useful for patient care less than half of the time at our center. Targeted ordering of these scans for indications in which they have greater utility, such as suspected osteomyelitis and vascular access infections, may optimize test utilization.