Leukocyte Scintigraphy Research Articles

Late Dacron Patch Inflammatory Reaction after Carotid Endarterectomy

The aim was to analyse the incidence and presentation of carotid patch inflammatory reactions following carotid endarterectomy (CEA). This was a cohort study using a prospectively maintained database. All patients who underwent elective CEA at a tertiary vascular centre between 2002 and 2016 were included. Computed tomography scan angiogram, duplex scan, and leucocyte scintigraphy were used to assess patients with suspected inflammatory patch complications. Re-intervention procedures and outcomes were noted. Histopathology and organisms cultured from the harvested material during re-intervention were assessed. During the study period, 633 patients underwent elective CEA. Fifty-one underwent eversion endarterectomy: 111 did not require a patch, whereas 471 patients had a patch repair. Four hundred and twenty eight had a Dacron patch repair and 43 a biological patch. Eight patients returned with late Dacron patch inflammatory complications (1.3% of all CEA and 1.9% of Dacron patch closures) after a period ranging from 18 months to 7 years (mean 4.1±2.1 years). Seven of the eight patients underwent surgical re-intervention, and the eighth patient was deemed high surgical risk. One patient underwent a vein bypass, three had vein patch repair, one required internal carotid artery (ICA) ligation after patch excision, and two were managed by debridement, with omohyoid and sternomastoid muscle covering of the patch. The patient who required ICA ligation suffered a fatal stroke. The remaining patients had a satisfactory outcome. All patients showed evidence of foreign body reaction in pathological examination with no pathological organism cultured from swabs or tissue harvested during surgery. Late wound complications after CEA may be related to inflammatory reaction of the Dacron patch rather than infection. Infection should be excluded first. Reconstruction with vein is effective. However, debridement with sternomastoid and omohyoid muscle covering of the patch may be considered in high risk patients after exclusion of infection with regular follow-up.

Detection of Osteomyelitis in the Diabetic Foot by Imaging Techniques: A Systematic Review and Meta-analysis Comparing MRI, White Blood Cell Scintigraphy, and FDG-PET

Diagnosing bone infection in the diabetic foot is challenging and often requires several diagnostic procedures, including advanced imaging. We compared the diagnostic performances of MRI, radiolabeled white blood cell (WBC) scintigraphy (either with 99mTc-hexamethylpropyleneamineoxime [HMPAO] or 111In-oxine), and [18F]fluorodeoxyglucose positron emission tomography (18F-FDG-PET)/computed tomography. We searched Medline and Embase as of August 2016 for studies of diagnostic tests on patients known or suspected to have diabetes and a foot infection. We performed a systematic review using criteria recommended by the Cochrane Review of a database that included prospective and retrospective diagnostic studies performed on patients with diabetes in whom there was a clinical suspicion of osteomyelitis of the foot. The preferred reference standard was bone biopsy and subsequent pathological (or microbiological) examination. Our review found 6,649 articles; 3,894 in Medline and 2,755 in Embase. A total of 27 full articles and 2 posters was selected for inclusion in the analysis. The performance characteristics for the 18F-FDG-PET were: sensitivity, 89%; specificity, 92%; diagnostic odds ratio (DOR), 95; positive likelihood ratio (LR), 11; and negative LR, 0.11. For WBC scan with 111In-oxine, the values were: sensitivity, 92%; specificity, 75%; DOR, 34; positive LR, 3.6; and negative LR, 0.1. For WBC scan with 99mTc-HMPAO, the values were: sensitivity, 91%; specificity, 92%; DOR, 118; positive LR, 12; and negative LR, 0.1. Finally, for MRI, the values were: sensitivity, 93%; specificity, 75%; DOR, 37; positive LR, 3.66, and negative LR, 0.10. The various modalities have similar sensitivity, but 18F-FDG-PET and 99mTc-HMPAO-labeled WBC scintigraphy offer the highest specificity. Larger prospective studies with a direct comparison among the different imaging techniques are required.

Bone scan in painful knee arthroplasty: obsolete or actual examination?

To assess and discuss current knowledges about the diagnostic value of the various scans in TKA failure alone. We perform a pubmed/medline search to identify all papers published in the literature matching the following key words: "total knee arthroplasty", "bone", "scintigraphy", "imaging", "three-phase", "triple-phase", "99mTc-HDP", "99mTc-MDP", "99mTc-hydroxymethane diphosphonate", and "99m Tc-methylenediphosphonate", "leukocyte scanning", "labeled leukocyte scintigraphy", "antigranulocyte", "nuclear medicine", "septic loosening", "aseptic loosening" and "infection". Three phases bone scintigraphy results an early diagnostic screening test or part of the preoperative tests for painful TKA and when PJI is suspected. Instead, leukocyte/bone marrow scintigraphy is superior to other scintigraphic tools in diagnosis of TKA infections. Granulocyte scintigraphy, seems to be an excellent choice when the diagnosis is unclear. Moreover, nuclear diagnostic tests showed different diagnostic accuracy between TKA and THA. Although nuclear diagnostic tests for THA failure are superior in diagnostic accuracy compared to TKA, NM scintigraphy is still an effective tool in the identification of chronic, low grade PJI. To date, scintigraphic exams have an higher levels of sensitivity, specificity and accuracy. Currently, leukocyte/bone marrow scintigraphy is considered the gold standard for this aim. Nevertheless, further studies are needed to assess and improve the accuracy of the scintigraphic exams in order to discriminate the causes of failure for painful TKA.

A retrospective analysis of the accuracy of radioactively labeled autologous leukocytes in patients with infected prosthetic joints.

Labeled leukocyte scintigraphy (LS) is considered a valuable tool in preoperative diagnosis of prosthetic joint infections (PJI). The aim of this study was to determine the accuracy of LS combined with bone marrow scintigraphy (BMS), as well as inflammation markers CRP and WBC, in detecting infection in patients with prosthetic joints. This study included patients suspected of having PJI between January and September 2013 at the Vienna General Hospital who underwent imaging with 99mTc-HMPAO labeled autologous leukocytes and subsequent BMS. Diagnostic accuracy was assessed in terms of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). A total of 48 patients were included. The most common joint investigated was knee (25), followed by hip (9), shoulder (2), and elbow (1). Other parts of the body investigated included the femur (6), tibia (2), leg (2), and foot (1). The pathogens most frequently isolated included Staphylococcus epidermidis and Candida albicans. The sensitivity of LS was 60%, specificity 97%, PPV 86% and NPV 90%. Overall accuracy was calculated to be 90%. This study was able to demonstrate that 99mTc-HMPAO labeled autologous leukocytes in patients presenting with symptoms of PJI is accurate. In contrast, however, inflammation markers CRP and WBC are not accurate pre-diagnostic markers for PJI.

Erratum to: What is the Accuracy of Nuclear Imaging in the Assessment of Periprosthetic Knee Infection? A Meta-analysis.

Erratum to: Clin Orthop Relat Res DOI 10.1007/s11999-016-5218-0 In the published study, “What is the Accuracy of Nuclear Imaging in the Assessment of Periprosthetic Knee Infection? A Meta-analysis” several errors can be found throughout the manuscript. In Table 1, the column title, “Number of hip prostheses (total/infected)” should be: “Number of knee prostheses (total/infected).” In Table 2, the column title, “Hip prostheses (primary/revision)” should be: “Knee prostheses (primary/revision).” In the legend for Table 2, “H = hybrid hip prostheses” should be removed. In the Discussion section, Figure 5A-B is incorrect as published. The corrected Fig. 5A-B is shown in this erratum.Fig. 5A-B: The pooled (A) sensitivity and (B) specificity of leukocyte scintigraphy in the assessment of periprosthetic knee infection with 95% CIs are shownThe title of Table 14 is incorrect. The title should be: “Diagnostic accuracy of fluorodeoxyglucose-positron emission tomography for detection of periprosthetic knee infection.” The title of Table 15 is incorrect. The title should be: “Study characteristics of fluorodeoxyglucose positron emission tomography for detection of periprosthetic knee infection.” Additionally, Figure 8A-B is incorrect as published. The corrected Fig. 8A-B is shown in this erratum. The authors apologize for the errors.Fig. 8A-B: The pooled (A) sensitivity and (B) specificity of FDG-PET in the assessment of periprosthetic knee infection with 95% CIs are shown. FDG-PET = fluorodeoxyglucose-positron emission tomography.

99mTc-labeled White Blood Cell Scan as a Guide to Open Biopsy in the Management of Hip and Knee Prosthesis Infection: Preliminary Results.

The aim of the present prospective study was to evaluate the usefulness of labeled leukocyte scan as a guide to open biopsy for the management of hip and knee prosthesis infection in patients without loosening of orthopedic device. Twenty-six patients with suspected hip (24) and knee (2) prosthesis infection underwent routine analysis of blood, plain radiography and 99mTc-HMPAO labelled leukocyte scan (WBCS). On these basis, patients were subdivided in the following groups: bone infection without loosening (n°=14), septic loosening (n°=8), superficial infection (n°=2), no infection (n°=2). Patients with septic loosening underwent empirical antibiotic therapy in order to avoid two-stage reimplantation. When the medical treatment was effective patients were submitted to one-stage operation. Patients without loosening of prosthesis but positive WBCS results underwent open biopsy: bone samples and periprosthetic tissues were taken from the regions showing pathological leukocyte uptake at the scan. Samples were submitted to microbiological examination and antibiotic treatments were undertaken in cases of bacterial growth. A 24-months clinical and instrumental follow-up was carried out in all patients. WBCS showed 22 patients affected by bone infection, 2 by superficial infection and 2 not infected. Height out of the 22 patients affected by deep infection had a septic loosening. In these cases, the medical treatment was inadequate in 6 patients and effective in 2. Fourteen patients with bone infection without loosening were submitted to open biopsy: in 9 cases a complete remission of the disease was found. Two patients, without infection, underwent single-stage surgery for mechanical problems. Superficial infection was assessed and successfully treated in 2 patients. The obtained results indicate that a multidisciplinary approach to infection of orthopedic prostheses, characterized by the combined use of open biopsy, WBC, and microbiological examination, produced positive outcome in 9 out of 14 patients.

Positron Emission Tomography and Single-Photon Emission Computed Tomography Imaging in the Diagnosis of Cardiac Implantable Electronic Device Infection: A Systematic Review and Meta-Analysis.

The use of cardiac implantable electronic devices (CIED) is increasing, and their associated infections result in significant morbidity and mortality. The introduction of better cardiac imaging techniques could be useful for diagnosing this condition and guiding therapy. Our objective was to systematically assess the diagnostic accuracy of Fluor-18-fluorodeoxyglucose positron emission tomography and computed tomography, labeled leukocyte scintigraphy (LS), and Gallium-67 citrate scintigraphy for the diagnosis of CIED infection. A systematic review of the literature and meta-analysis on the use of all 3 modalities in CIED infection were conducted. Pooled sensitivity, specificity, and summary receiver operating characteristic curves of each imaging modalities were determined. The literature search identified 2493 articles. A total of 13 articles (11 studies for 18F-FDG PET-CT and 2 for LS), met the inclusion criteria. No studies for 67Ga citrate scintigraphy met the inclusion criteria. The pooled sensitivity of 18F-FDG PET-CT for the diagnosis of CIED infection was 87% (95% CI, 82%-91%) and pooled specificity was 94% (95% CI, 88%-98%). The summary receiver operating characteristic curve analysis demonstrated good overall accuracy, with an area under the curve of 0.935. There were insufficient data to do a meta-analysis for LS, but both studies reported sensitivity above 90% and specificity of 100%. Both 18F-FDG PET-CT and LS yield high sensitivity, specificity, and accuracy, and thus seem to be useful for the diagnosis of CIED infection, based on robust data for 18F-FDG PET-CT but limited data for LS. When available,18F-FDG PET-CT may be preferred.

Left ventricular assist pump pocket infection: conservative treatment strategy for destination therapy candidates.

Heart failure is a major cause of mortality and morbidity, particularly among patients with advanced disease and no access to cardiac transplantation. LVAD implantation is not only a bridge-to-transplantation option for patients awaiting a heart donor, but is often used as bridge-to-destination therapy in patients unsuited for transplantation for various reasons. LVAD infection is considered the second-most common cause of death in patients who survive the initial 6 months on LVAD support. Few reports describe the indications for chronic suppressing antibiotic therapy, device exchange, methods for exchanging infected devices, post-exchange antimicrobial management status, and the outcomes of such patients. This is the case of a 74-year-old male patient with numerous comorbidities who received urgent surgical management for severe heart failure with a HeartMate II. Six months later he developed an LVAD pump infection with methicillin-resistant Staphylococcus epidermidis, which was diagnosed with leucocyte scintigraphy. The patient received an omental graft over the LVAD and a chronic suppressive antibiotic regime. A marked leukocyte scintigraphy showed the infection's regression 6 months after the initiation of antibiotic treatment. We concisely reviewed the driveline infections and the main aspects of the LVAD pump infection. We reviewed options for conservative and nonconservative management and showed that conservative management of the LVAD pump infection is possible. There are no defined recommendations for the management of LVAD pump infection. This case is among the few in the literature showing that conservative treatment of an LVAD pump infection is possible.

The ideal dual-isotope imaging combination in evaluating patients with suspected infection of pelvic pressure ulcers.

The successful management of infected pelvic pressure ulcer patients (PPUP) depends on the distinction between infections limited to soft tissue (STI) and those with underlying osteomyelitis (OM), which can be difficult to determine clinically. Dual-isotope (DI) comprehensive imaging has excellent accuracy in localizing diabetic foot infection and differentiating OM from STI with SPECT/CT utilization. In this study, we assess the accuracy and confidence of the different DI SPECT/CT imaging steps in PPUP with confirmed diagnoses. Pelvic flow and blood pool imaging were followed by labeled white blood cell reinjection and Tc-99m hydroxymethylene-diphosphonate bone (bone scan) and In-111-leukocytes (white blood cell scan) DI planar and SPECT/CT (step 1) acquisitions. Tc-99m sulfur colloid (bone marrow scan)/WBCS SPECT/CT (step 2) images were obtained on the following day. DI step 1 planar, step 1 SPECT/CT, step 2 SPECT/CT, and combined step 1/step 2 SPECT/CT were reviewed separately for diagnosis and diagnosis confidence. The final diagnosis was confirmed by culture/pathology in 21 patients and clinical/imaging follow-up in 12 patients. There were 19 OM patients, three STI patients, and 11 patients with no infection. The final diagnosis agreement to DI combined step 1/step 2 SPECT/CT was higher than DI step 2 or step 1 SPECT/CT alone, or DI step 1 planar, as assessed by λ and error reduction %, respectively. Combined DI step 1/step 2 SPECT/CT was more sensitive than DI step 2 SPECT/CT and more specific than DI step 1 SPECT/CT, and showed higher diagnostic confidence than both imaging techniques. DI SPECT/CT is highly useful in evaluating PPUP with suspected infection. DI step 1 is more sensitive, whereas step 2 is more specific. Both step 1 and step 2 DI SPECT/CT images are needed to accurately and confidently assess for infection and distinguish OM from STI, which are crucial for optimal management.

Cardiac Imaging of Infective Endocarditis, Echo and Beyond.

The visualization of cardiac lesions is a major component of the diagnosis of infective endocarditis (IE). We review the usefulness of different cardiac imaging techniques for the diagnosis and management of IE. Transthoracic echocardiography is indicated in all cases of suspected IE. Transesophageal echocardiography is used in most patients due to its higher sensitivity. When diagnosis remains doubtful, in particular for IE on foreign material, multislice computed tomography and nuclear medicine techniques, i.e., positron emission tomography and radiolabelled leucocyte scintigraphy, enable a higher proportion of IE to be classified as definite or rejected at an early stage. Imaging also plays a role in prognostic stratification and follow-up. Nuclear medicine and radiological imaging techniques are useful to diagnose cardiac lesions on IE when echocardiography is not conclusive. They should be used in selected patients and their findings should be integrated in a multidisciplinary management in endocarditis teams.

Post Mortem Leukocyte Scintigraphy in Juvenile Pigs with Experimentally Induced Osteomyelitis.

We have previously demonstrated that 111In-labeled autologous leukocyte scintigraphy is able to detect osteomyelitis in living juvenile pigs. In animal research studies, it may well be an advantage if the animals could be scanned after euthanasia. Applying traditional scanning of living animals to euthanized animals will render anaesthesia unnecessary and be ideal for obtaining good and reliable scans for the correct interpretation of imaging afterwards, since the animals do not move. The autologous leukocytes of the pigs were collected, marked with 111In, and reinjected into the pigs and allowed for homing to the site of infections as usual while the pigs were alive. In this study, we demonstrate that it is possible to perform SPECT/CT with 111In-labelled autologous leukocytes almost 24 hrs after euthanasia with the same detectability of osteomyelitic lesions as in living pigs (78% versus 79%). The pigs in this study had exactly the same experimental conditions as the living pigs and were examined in parallel with the living pigs except for euthanasia prior to the leukocyte scan and that no PET/CT scans were performed.

Using Nuclear Medicine Imaging Wisely in Diagnosing Infectious Diseases.

In recent years, there has been an increasing emphasis on efficient and accurate diagnostic testing, exemplified by the American Board of Internal Medicine’s “Choosing Wisely” campaign. Nuclear imaging studies can provide early and accurate diagnoses of many infectious disease syndromes, particularly in complex cases where the differential remains broad.This review paper offers clinicians a rational, evidence-based guide to approaching nuclear medicine tests, using an example case of methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia in a patient with multiple potential sources. Fluorodeoxyglucose-positron emission tomography (FDG-PET) with computed tomography (CT) and sulfur colloid imaging with tagged white blood cell (WBC) scanning offer the most promise in facilitating rapid and accurate diagnoses of endovascular graft infections, vertebral osteomyelitis (V-OM), diabetic foot infections, and prosthetic joint infections (PJIs). However, radiologists at different institutions may have varying degrees of expertise with these modalities. Regardless, infectious disease consultants would benefit from knowing what nuclear medicine tests to order when considering patients with complex infectious disease syndromes.

Scintigraphic Patterns of Indium-111 Oxine-Labeled White Blood Cell Imaging of Gram-Negative versus Gram-Positive Vertebral Osteomyelitis

Objective: The goal of the study was to investigate whether or not gram-negative organisms that secrete antichemotactic factors cause the nonaccumulation pattern of ¹¹¹In-oxine-labeled white blood cell (¹¹¹In-WBC) scans. Materials and Methods:Staphylococcus aureus (gram-positive) (group 1) was injected into 25 rabbits and Escherichia coli (gram-negative) (group 2) into another 25 to induce infection in the lumbar vertebrae or left thigh bone (femur). Sixteen successfully infected and surviving rabbits from each group were used for imaging and analysis. Of the 16 rabbits, each group included 8 with vertebral infection and 8 with femur infection. For imaging, each rabbit was injected intravenously with 11.1 MBq (300 μCi) ¹¹¹In-WBC, and images were acquired 24 h later. Microscopic histopathology was performed after decalcification to confirm osteomyelitis. Results: The ¹¹¹In-WBC accumulation was observed in 7 (87.5%) of the 8 rabbits infected with S. aureus in the vertebrae and thigh bone. Of the rabbits infected with the gram-negative vertebrae, 1 (12.5%) showed little accumulation of ¹¹¹In-WBC. Of the 8 rabbits with gram-negative-infected femurs, 1 had high accumulation and another had low accumulation of ¹¹¹In-WBC, while the rest did not show any uptake. Osteomyelitis was confirmed by histopathology in all the successfully infected rabbits used for imaging. Conclusion: In the majority of the gram-positive-infected rabbit vertebrae there was high accumulation of ¹¹¹In-WBC. However, no accumulation of ¹¹¹In-WBC was observed in most of the vertebrae infected with gram-negative organisms, which release antichemotactic factors that prevent adequate accumulation of WBC at the infected area.

Non Infectious Cavitary Lung Lesions in a Patient with Adult Onset Still’s Disease: A Case Report

Acute Onset Still’s Disease (AOSD) is a disease of immunologic and hematologic dysfunction, whereby a percentage of cases develop further into Macrophage Activating Syndrome (MAS). This patient is a 35 year old Caucasian male with Acute Onset Still’s Disease without MAS was hospitalized for multiple cavitary lung lesions. Lesions included a larger estimated 2.5 cm x 2.5 cm cavitary lesion in the Right Middle Lobe and smaller estimated 1.3 x 1.4 cm and 1.8 x 1.2 cm lesions in the Left Lower Lobe of the lungs. The larger lesion was seen on chest X-ray a further detailed on a chest CT scan, which revealed the remaining two smaller pulmonary lesions. The patient experienced undulating fevers as high as 101°F. The patient was put on isolation and received serial blood cultures, sputum cultures, acid fast stains of sputum, urine cultures, viral film array serology all resulting in negative results. Over seven acid fast bacilli stains of sputum were negative in the setting of multiple cavitary lung lesions with high suspicion of active Tuberculosis. The patient received immediate broad spectrum antibiotic and antifungal intravenous antibiotics without relief in fever or symptoms. The patient received a full body Indium scan and MRI of the brain looking for a source of possible infection and further classification of his disease; both of which were negative. The blood and sputum fungal and bacterial cultures were negative. Serial chest CT and chest X-ray demonstrated slightly smaller cavitary lung lesions with thinner walls. The suspicion of Tuberculosis remained high and a lung biopsy was obtained of the large cavitary lesion in the Left Middle Lobe, which did not demonstrate acid fast staining on three separate samples. This patient was concluded to have noninfectious cavitary lung lesions and discharged home with close follow up. He is the first patient reported with AOSD Disease without MAS hospitalized for undulating fevers and multiple cavitary lung lesions without evidence of Tuberculosis of active infection.

Vascular Graft Infections, Mycotic Aneurysms, and Endovascular Infections: A Scientific Statement From the American Heart Association.

### Background The use of synthetic material for reconstructive vascular surgery was first reported during the early 1950s. Infection involving vascular graft prostheses is an infrequent but devastating complication of reconstructive vascular graft surgery and is associated with a high morbidity and, in some situations, mortality. Improvements in surgical techniques and graft design, including the use of native venous or arterial tissue, have reduced the frequency of infection and severity of complications from vascular graft infection (VGI). However, these advances have also led to more frequent vascular graft procedures occurring in a patient population with multiple underlying comorbidities that would have previously disqualified them as candidates for vascular reconstructive surgery. Underlying comorbidities, such as diabetes mellitus or immune compromise, increase the risk of infection and serious infection-related complications. The major complications of VGI include sepsis, amputation, disruption of infected anastomotic suture line with rupture or pseudoaneurysm formation, embolization of infected thrombi, reinfection of reconstructed vascular grafts, enteric fistulae to the small or large bowel, bacteremic spread of infection to other sites, and death. VGIs can be categorized broadly into those that occur in an extracavitary location, primarily in the groin or lower extremities, or in an intracavitary location, primarily within the abdomen or less commonly within the thorax. ### Frequency The frequency of VGI depends on the anatomic location of the graft. The infection rate is 1.5% to 2% for most extracavitary grafts and as high as 6% with vascular grafts in the groin.1–9 For intracavitary grafts, the infection rate is ≈1% to 5%.1–6 Graft infection is most common after emergency procedures and after reoperation.1–4,10 Aortic graft erosion or fistulous communication into the duodenum or other areas of the bowel reportedly occurs in 1% to 2% of patients after aortic reconstruction.11, …

The Accuracy of Imaging Techniques in the Assessment of Periprosthetic Hip Infection: A Systematic Review and Meta-Analysis.

Various imaging techniques are used for excluding or confirming periprosthetic hip infection, but there is no consensus regarding the most accurate technique. The objective of this study was to determine the accuracy of current imaging modalities in diagnosing periprosthetic hip infection. A systematic review and meta-analysis of the literature was conducted with a comprehensive search of MEDLINE and Embase to identify clinical studies in which periprosthetic hip infection was investigated with different imaging modalities. The sensitivity and specificity of each imaging technique were determined and compared with the results of microbiological and histological analysis, intraoperative findings, and clinical follow-up of >6 months. A total of 31 studies, published between 1988 and 2014, were included for meta-analysis, representing 1,753 hip prostheses. Quality assessment of the included studies identified low concerns with regard to external validity but more concerns with regard to internal validity including risk of bias (>50% of studies had insufficient information). No meta-analysis was performed for radiography, ultrasonography, computed tomography, and magnetic resonance imaging because of insufficient available clinical data. The pooled sensitivity and specificity were 88% (95% confidence interval [CI], 81% to 94%) and 92% (95% CI, 88% to 96%), respectively, for leukocyte scintigraphy; 86% (95% CI, 80% to 90%) and 93% (95% CI, 90% to 95%) for fluorodeoxyglucose positron emission tomography (FDG PET); 69% (95% CI, 58% to 79%) and 96% (95% CI, 93% to 98%) for combined leukocyte and bone marrow scintigraphy; 84% (95% CI, 70% to 93%) and 75% (95% CI, 66% to 82%) for antigranulocyte scintigraphy; and 80% (95% CI, 72% to 86%) and 69% (95% CI, 64% to 73%) for bone scintigraphy. 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. Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

THE ACCURACCY OF PET AND SPECT IMAGING IN THE DIAGNOSIS OF IMPLANTABLE ELECTRONIC CARDIAC DEVICE INFECTION: A SYSTEMATIC REVIEW AND META-ANALYSIS

Implantable electronic cardiac device (IECD) infection is a serious and potentially life-threatening process. Timely and accurate diagnosis is paramount since it can have an impact on clinical decisions regarding the need for surgery or device extraction. Presentation varies widely and the diagnosis remains clinically challenging. Labelled leucocyte (WBC) scintigraphy and 67Ga scintigraphy are well established inflammation and infection imaging modalities and have both been used to help in the diagnosis and assessment of this condition. Over the last decade, clinical studies have demonstrated that 18F-FDG PET/CT is a promising diagnostic technique in the detection of localized inflammation and infectious foci in patient with IECD infection. A systematic literature review was performed to determine and compare the accuracy of these modalities in the diagnosis of IECD infection.

Multimodal Diagnostic Approach to Monoarthritis of the Wrist

Objective: The aim of this study was to evaluate both the performance characteristics of magnetic resonance imaging (MRI) in the differential diagnosis of monoarthritis of the wrist and the predictive ability of the 1987 American College of Reumatology (ACR) and 2010 ACR/European League Against Rheumatism (EULAR) criteria. Methods: The 29 patients with monoarthritis of the wrist retrospectively reviewed in this study underwent preoperative MRI with or without a white blood cell (WBC) scan. Their diagnoses were confirmed histologically after open synovectomy. Synovitis, bone erosion, and bone edema, as seen on MRI, were measured by 2 readers independently using the Outcome Measures in Rheumatology Clinical Trials (OMERACT) Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS) system. Receiver operating characteristic (ROC) curves were used to calculate the cutoff differentiating rheumatoid arthritis (RA) from other diseases. The optimized cutoff point for each parameter was determined using Youden index. Results: The areas under the ROC curves for the synovitis, bone erosion, and bone edema scores were 0.892, 0.853, and 0.752, respectively. The cutoff values of these scores to predict RA were 5, 48, and 19, respectively. The sensitivity and specificity of the 1987 ACR criteria were 50% and 92% and those of the 2010 ACR/EULAR criteria were 60% and 75%. Conclusion: The OMERACT RAMRIS system provides a valuable tool to differentiate RA from tuberculosis and undifferentiated chronic monoarthritis in patients with wrist monoarthritis. A multimodal diagnostic approach using MRI, WBC scan, and histologic evaluation is recommended if the diagnosis cannot be established based on clinical, biochemical, and radiographic evaluations.

Diagnosis of Periprosthetic Infection - What's Obligation, What's Optional?

Periprothetic infection after primary or revision arthroplasty is of increasing importance. The incidence of infection in primary arthroplasty is approximately 1 %. Revision arthroplasty has higher infection rates, which increase with the number of revision surgeries. Aim of this Paper: An overview of the current diagnosis of periprosthetic infection. This selective analysis is based on a lecture by the author at the DKOU 2015. Periprosthetic infection is taken as having been demonstrated when either two periprosthetic cultures contain the same microorganism, or if there is a fistula communicating with a joint. If only minor criteria are met, the detection of an infection is more difficult. The medical history only provides supporting evidence, especially as regards the course of the pain. Physical examination is more helpful, especially if there is redness, swelling, heat or wound dehiscence. Radiological pathologies, such as osteolysis or bone resorption can only be found in advanced infections. Nuclear medicine scans only possess acceptable sensitivity and specificity in combination with leukocyte scintigraphy. ESR, CRP and leukocyte blood count of the blood are of poor specificity. Important and targeted diagnostic steps include joint aspiration under aseptic conditions, although this exhibits a relatively high rate of false negative results. The conditions for this must be stringently observed. This is usefully complemented by cytological examinations and biopsies for tissue culture. Sensitivity and specificity are then increased. Sonication can significantly enhance the detection of an infection. The leukocyte esterase test is inexpensive and easy to perform and is therefore very much in vogue at the moment; however it is useless if there is contamination with blood. Recent studies indicate that the alpha-defensin test possesses high sensitivity and specificity, but has the disadvantage of being expensive. In patients with suspected periprosthetic infection, the primary aim is either to exclude an infection, or to detect a pathogen. The essential components are careful evaluation of the medical history, accompanied by imaging and laboratory tests. A critical approach is essential. Joint aspiration has become the gold standard in detecting periprosthetic infections. This should be performed in conjunction with a cytological analysis of the synovial fluid. An improvement in sensitivity and specificity can be archived by taking tissue samples. Sonication significantly improves the results. The latter method, the leukocyte esterase test and the alpha-defensin test are optional. The essential components are a rigorous evaluation, a clear algorithm and interdisciplinary collaboration with microbiologists and possibly infectiologists.

Role of PET/CT in Workup of Fever without a Source.

Fever without source is a febrile illness without localizing signs or initial obvious cause. Early workup will often include chest radiography and computed tomography (CT) of the abdomen and pelvis, with or without CT of the chest. To evaluate localizing signs or symptoms or to further evaluate findings from initial studies, targeted imaging according to body part can be performed by using radiography, ultrasonography, CT, or magnetic resonance (MR) imaging. Nuclear medicine studies can provide imaging of the whole body and may be helpful when the clinical and conventional imaging workup findings are negative or equivocal in identifying a source of fever. Nuclear medicine studies can be used to detect pathologic changes early in a disease course, even in the absence of an anatomic abnormality. Gallium 67 scintigraphy, indium 111- and technetium 99m-labeled leukocyte scintigraphy, and fluorine 18 fluorodeoxyglucose positron emission tomography (PET)/CT studies are all useful in the evaluation of fever, but the radiopharmaceutical cost for PET/CT is much lower than that for radiolabeled leukocyte studies. The increased use of bundled payments for inpatient admissions requires updated cost evaluations for the preferred nuclear medicine study. For inpatients in whom the findings from the initial clinical workup and imaging studies are nondiagnostic, PET/CT examination may be preferable to radiolabeled leukocyte studies because of its high sensitivity and lower cost. Negative findings at PET/CT can be helpful in excluding a suspected site of infection, and positive findings at PET/CT can be helpful in confirming a suspected site of infection or in identifying an unexpected cause of fever. (©)RSNA, 2016.