In-111 WBC imaging of osteomyelitis in patients with underlying bone scan abnormalities

Imaging tests for the detection of osteomyelitis: a systematic review

BACKGROUND

Osteomyelitis is an infection of the bone. Medical imaging tests, such as radiography, ultrasound, magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT) and positron emission tomography (PET), are often used to diagnose osteomyelitis.

OBJECTIVES

To systematically review the evidence on the diagnostic accuracy, inter-rater reliability and implementation of imaging tests to diagnose osteomyelitis.

DATA SOURCES

We conducted a systematic review of imaging tests to diagnose osteomyelitis. We searched MEDLINE and other databases from inception to July 2018.

REVIEW METHODS

Risk of bias was assessed with QUADAS-2 [quality assessment of diagnostic accuracy studies (version 2)]. Diagnostic accuracy was assessed using bivariate regression models. Imaging tests were compared. Subgroup analyses were performed based on the location and nature of the suspected osteomyelitis. Studies of children, inter-rater reliability and implementation outcomes were synthesised narratively.

RESULTS

Eighty-one studies were included (diagnostic accuracy: 77 studies; inter-rater reliability: 11 studies; implementation: one study; some studies were included in two reviews). One-quarter of diagnostic accuracy studies were rated as being at a high risk of bias. In adults, MRI had high diagnostic accuracy [95.6% sensitivity, 95% confidence interval (CI) 92.4% to 97.5%; 80.7% specificity, 95% CI 70.8% to 87.8%]. PET also had high accuracy (85.1% sensitivity, 95% CI 71.5% to 92.9%; 92.8% specificity, 95% CI 83.0% to 97.1%), as did SPECT (95.1% sensitivity, 95% CI 87.8% to 98.1%; 82.0% specificity, 95% CI 61.5% to 92.8%). There was similar diagnostic performance with MRI, PET and SPECT. Scintigraphy (83.6% sensitivity, 95% CI 71.8% to 91.1%; 70.6% specificity, 57.7% to 80.8%), computed tomography (69.7% sensitivity, 95% CI 40.1% to 88.7%; 90.2% specificity, 95% CI 57.6% to 98.4%) and radiography (70.4% sensitivity, 95% CI 61.6% to 77.8%; 81.5% specificity, 95% CI 69.6% to 89.5%) all had generally inferior diagnostic accuracy. Technetium-99m hexamethylpropyleneamine oxime white blood cell scintigraphy (87.3% sensitivity, 95% CI 75.1% to 94.0%; 94.7% specificity, 95% CI 84.9% to 98.3%) had higher diagnostic accuracy, similar to that of PET or MRI. There was no evidence that diagnostic accuracy varied by scan location or cause of osteomyelitis, although data on many scan locations were limited. Diagnostic accuracy in diabetic foot patients was similar to the overall results. Only three studies in children were identified; results were too limited to draw any conclusions. Eleven studies evaluated inter-rater reliability. MRI had acceptable inter-rater reliability. We found only one study on test implementation and no evidence on patient preferences or cost-effectiveness of imaging tests for osteomyelitis.

LIMITATIONS

Most studies included < 50 participants and were poorly reported. There was limited evidence for children, ultrasonography and on clinical factors other than diagnostic accuracy.

CONCLUSIONS

Osteomyelitis is reliably diagnosed by MRI, PET and SPECT. No clear reason to prefer one test over the other in terms of diagnostic accuracy was identified. The wider availability of MRI machines, and the fact that MRI does not expose patients to harmful ionising radiation, may mean that MRI is preferable in most cases. Diagnostic accuracy does not appear to vary with the potential cause of osteomyelitis or with the body part scanned. Considerable uncertainty remains over the diagnostic accuracy of imaging tests in children. Studies of diagnostic accuracy in children, particularly using MRI and ultrasound, are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017068511.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 61. See the NIHR Journals Library website for further project information.

Consensus document for the diagnosis of prosthetic joint infections: a joint paper by the EANM, EBJIS, and ESR (with ESCMID endorsement)

Background

For the diagnosis of prosthetic joint infection, real evidence-based guidelines to aid clinicians in choosing the most accurate diagnostic strategy are lacking.

Aim and Methods

To address this need, we performed a multidisciplinary systematic review of relevant nuclear medicine, radiological, orthopaedic, infectious, and microbiological literature to define the diagnostic accuracy of each diagnostic technique and to address and provide evidence-based answers on uniform statements for each topic that was found to be important to develop a commonly agreed upon diagnostic flowchart.

Results and Conclusion

The approach used to prepare this set of multidisciplinary guidelines was to define statements of interest and follow the procedure indicated by the Oxford Centre for Evidence-based Medicine (OCEBM).

Electronic supplementary material

The online version of this article (10.1007/s00259-019-4263-9) contains supplementary material, which is available to authorized users.

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.

FDG PET Assessment of Osteomyelitis: A Review

This article discusses the role of [(18)F]Fluorodeoxyglucose (FDG) PET and PET/computed tomography in diagnosis and therapeutic response assessment for the management of patients with osteomyelitis, to increase awareness of imaging pitfalls and to improve understanding of specific technical and diagnostic challenges in patients with posttraumatic chronic osteomyelitis, spinal infections, prosthetic joint infections, and diabetic foot infections. This article focuses on the usefulness of modern imaging modalities in the setting of suspected infection or inflammation and on the role of FDG-PET in the management of patients with suspected or confirmed infection in the bones.

Critically evaluating the role of diagnostic imaging in osteomyelitis

Early diagnosis, essential for timely appropriate treatment and reduction of complications, can be difficult. This article aims to give an overview of the role that different imaging modalities have to play in the diagnosis of osteomyelitis. Osteomyelitis is a heterogeneous disease in its pathophysiology, clinical presentation, and management. It infers inflammation of bone and marrow, whereas osteitis is inflammation of the bone only. Thus, a soft-tissue infection that reaches the bone surface but has not infected the marrow is osteitis and not osteomyelitis. Chronic osteomyelitis is divided into active and inactive forms. Newly appearing periosteal reaction or bone destruction within the chronic involucrum are indicators of activation. Imaging modalities represent different underlying pathophysiological processes that may be represented in differing types and differing phases of osteomyelitis. Sequential selection of appropriate imaging modalities requires a thorough understanding of the disease processes and the process by which each modality visualizes this dynamic disease process.

Reliability of white blood cell scan in the follow-up of osteomyelitis

INTRODUCTION

The question of whether antibiotic treatment does or does not affect reliability of white blood cell scan (WBCS) to detect disease activity in clinical practice is still unanswered. Our aim was to study the relationship between scintigraphic findings of WBCS and antibiotic therapy in a group of patients affected with osteomyelitis (OM).

METHODS

We retrospectively reviewed 57 scans, performed in 18 patients affected by OM and who were on antibiotic treatment. The number of therapy weeks was calculated for each antibiotic. A comparison of results obtained during and after discontinuation of the antibiotic treatment was made. Overall sensitivity, specificity and accuracy of WBCS were calculated and compared with those obtained in patients undergoing therapy.

RESULTS

Forty-seven scans were performed during treatment and 10 scans after discontinuation of treatment. The scintigraphic results obtained during and after discontinuation of treatment were as follows: TN 14 and 8, TP 31 and 2, FN 2 and 0, FP 0 and 0, respectively. Sensitivity, specificity and accuracy of WBCS, calculated in all patients, were 94.3%, 100% and 96.5% respectively. In patients receiving antibiotic therapy, the same parameters were 93.9%, 100% and 95.7% respectively. In patients treated with antibiotics that can decrease leukocyte function, there were 10 TN, 14 TP, 2 FN and 0 FP, while in patients treated with antibiotics that have not effect on leukocyte function there were 4 TN, 17 TP, 0 FN and 0 FP.

CONCLUSION

The reliability of WBCS in the detection of disease activity during antibiotic treatment does not change significantly. It can be assumed that the influence of antibiotic therapy on labelled leukocyte behaviour is negligible.

Role of radionuclide imaging in the orthopedic patient

Since its introduction more than 40 years ago, nuclear medicine has played an important role in the diagnosis and detection of soft tissue and skeletal disorders. Skeletal scintigraphy or bone scanning is a diagnostic study used to evaluate the distribution of osteoblastic activity or active bone formation within the body. Because no single imaging technique is ideal in all clinical situations, selecting an appropriate imaging test depends on understanding the pathophysiology of the suspected condition and limitations of each technique. This article provides a brief overview of bone scintigraphy, infection imaging, and positron emission tomography in the context of current, adult orthopedic practice.

Evaluation of (111) Indium-Labeled Autologous Leukocyte Scintigraphy for the Diagnosis of Chronic Osteomyelitis in Patients With Grade IV Pressure Ulcers, as Compared With a Standard Diagnostic Protocol

Diagnosing osteomyelitis in patients with pressure ulcers is complicated by overlying soft-tissue inflammation and reactive bone formation. We set out to evaluate the efficacy of indium scanning in the diagnosis of chronic osteomyelitis in spinal-cord-injury patients with grade IV pressure ulcers. The goal was to estimate the sensitivity and specificity of indium scanning as compared with diagnostic modalities previously evaluated by the principal investigator. Our method was a retrospective chart review of cases at a university hospital. Eleven patients with pressure sores and suspected chronic osteomyelitis underwent indium scanning. The results were compared with ostectomy specimens taken at the time of reconstructive surgery and/or bone biopsy. The sensitivity and specificity were 100% and 50%, respectively. Indium scanning appears to be more sensitive than specific. These data suggest that the value of indium scanning may primarily be to rule out osteomyelitis and not as a primary diagnostic modality.

Bone infection in patients suspected of complicating osteomyelitis: the diagnostic value of dual isotope bone-granulocyte scintigraphy

AIM

The purpose of this study was to evaluate the diagnostic value of dual isotope bone-granulocyte scintigraphy in patients with known bone pathology clinically suspected of osteomyelitis, i.e. complicating osteomyelitis, using per-operative bacterial culture from bone as reference.

METHODS

Simultaneous dual isotope bone-granulocyte scintigraphic images were obtained in 42 consecutive patients in whom conventional X-ray, erythrocyte sedimentation rate, and C-reactive protein were also available. 99mTc MDP bone and 111In labelled granulocyte imaging was obtained simultaneously. The images were interpreted as positive for osteomyelitis if regions of interests of pathologic 111In granulocyte accumulation included 99mTc MDP activity on the bone images (except in the spine).

RESULTS

The sensitivity, specificity, and accuracy were 84, 71 and 79%, respectively, for simultaneous, dual isotope bone-granulocyte scintigraphy, higher than the other diagnostic parameters.

CONCLUSION

Simultaneous bone-granulocyte scintigraphy is a valuable diagnostic tool in diagnosing osteomyelitis complicating other bone pathology with or without soft-tissue infection.

Applications of fluorodeoxyglucose-PET imaging in the detection of infection and inflammation and other benign disorders

FDG-PET has great potential in the evaluation of a variety of inflammatory and infectious disorders and possibly other benign disorders. FDG-PET is very helpful in the evaluation of chronic osteomyelitis, sarcoidosis, FUO, and differentiating toxoplasmosis from lymphoma in the central nervous system in HIV-positive patients. The assessment of efficacy of FDG-PET in the evaluation of arthroplasty-associated infection, large-vessel vasculitis, and other inflammatory and infectious disorders is ongoing but seems quite promising at this time.

Is this bone infected or not? Differentiating neuro-osteoarthropathy from osteomyelitis in the diabetic foot

Osteomyelitis (bone infection) and neuro-osteoarthropathy (Charcot arthropathy) are limb-threatening complications of diabetic neuropathy with very different therapies. Distinguishing between them may be difficult, but it is important. In Charcot arthropathy, noninfectious soft tissue inflammation accompanies rapidly progressive destruction, first of joints, then of bone. This occurs in a well-vascularized and severely neuropathic, but nonulcerated, foot. In osteomyelitis, chronic soft tissue ulceration precedes infection of bone, which may be physically exposed. Magnetic resonance imaging and bone biopsy are the preferred diagnostic tests, provided adequate technical and interpretive skills are available.

Bone scintigraphic findings in patients with foot ulcers and normal plain film radiographs

A prospective study was performed to examine the performance of bone scintigraphy in the earliest stage of soft-tissue foot ulceration with potential risk for progression to osteomyelitis. Twenty-three podiatry clinic patients with new or recurrent foot ulcers but negative plain film radiographs of the foot underwent 24 (one patient was studied twice) multiphase bone scans (flow, blood pool, and 3- and 24-hour delayed images) that were visually scored for severity of increased uptake on a scale of 0 to 3+, with 0 indicating normal and 3+ indicating severe. Twenty-one scans (88%) showed abnormal uptake on at least one phase, with 17 (71%) having increased bone uptake on late images. Ulcer healing without complications occurred in 20 cases (83%), whereas 4 cases had adverse outcomes, 3 requiring surgical resection for failure to heal and 1 having radiographic progression to frank osteomyelitis. All three patients whose bone scans showed severe abnormal uptake had an adverse clinical outcome.

18-fluorodeoxyglucose positron emission tomographic imaging in the detection and monitoring of infection and inflammation

During the past decade, 18-fluorodeoxyglucose (FDG) positron emission tomography (PET) has rapidly evolved from a pure research modality to a clinical necessity. FDG-PET was introduced to determine the state of brain function in physiologic and pathologic states. Its use as a powerful tool to diagnose, stage, and monitor patients with a variety of malignancies has been truly revolutionary. However, FDG is a nonspecific tracer and it has been found to accumulate at sites of infection and inflammation. It is becoming evident that PET imaging will play a major role in the treatement of patients with suspected infection and inflammation. PET has been shown to be particularly valuable in the evaluation of chronic osteomyelitis, infected prostheses, sarcoidosis, fever of unknown origin, and acquired immunodeficiency syndrome. Because of its ability to quantitate the rate of FDG uptake, PET may prove to be a powerful modality for the monitoring of disease activity and response to therapy. Novel PET tracers are being tested for imaging infection and inflammation that may further enhance the role of this technique in the appropriate clinical setting. PET imaging to detect and characterize infection and inflammation may become a major clinical indication in the day-to-day practice of medicine.

Role of scintigraphy in musculoskeletal and spinal infections

Clinical findings are still the mainstay for suspecting the diagnosis of musculoskeletal infections, especially osteomyelitis. No single complementary imaging technique has 100% specificity and sensitivity for every case of musculoskeletal infection. Depending on the age of the patient, presence of orthopedic hardware, location of infection, underlying bone, and systemic conditions, the choice of imaging modalities must be tailored to the patient's condition. Plain radiographs are performed first and may be sufficient. In children, bone scan is highly accurate to diagnose osteomyelitis. Labeled leukocytes with complementary bone or bone marrow studies are recommended for orthopedic hardware or diabetic foot. Finally, gallium scanning is useful for the diagnosis of vertebral osteomyelitis. Current radiopharmaceuticals used for diagnosing infection also label inflammation. Newer products, as Infecton, should in the future allow better differentiation between infection and sterile inflammation.

Exclusion of chronic osteomyelitis with F-18 fluorodeoxyglucose positron emission tomographic imaging

PURPOSE

Excluding the diagnosis of chronic osteomyelitis is often difficult with noninvasive techniques, especially when bone anatomy and structure have been altered by trauma, surgery, or soft-tissue infection. It has been reported that fluorodeoxyglucose (FDG) positron emission tomography (PET) has excellent potential to diagnose osteomyelitis. In this study, the accuracy of FDG PET in the diagnosis of chronic osteomyelitis was determined.

METHOD

Twenty-two patients with possible osteomyelitis (5 in the tibia, 5 in the spine, 4 in the proximal femur, 4 in the pelvis, 2 in the maxilla, and 2 in the feet) who underwent FDG PET imaging and on whom operative or clinical follow-up data were available were included in this analysis. The final diagnosis was made by surgical exploration or clinical follow-up during a 1-year period.

RESULTS

FDG PET correctly diagnosed the presence or absence of chronic osteomyelitis in 20 of 22 patients. Six had chronic osteomyelitis and 16 proved to be free of osteomyelitis. FDG PET correctly identified all six patients with chronic osteomyelitis but produced two false-positive results. This study had a sensitivity rate of 100%, a specificity rate of 87.5%, and an accuracy rate of 90.9%.

CONCLUSION

FDG PET is a highly effective imaging method to exclude osteomyelitis when a negative scan result is obtained. However, positive results can be caused not only by true osteomyelitis but also by inflammation in the bone or surrounding soft tissues as a result of other causes. Overall, FDG PET may prove to be the preferred study in the management of patients with possible chronic osteomyelitis.

Efficacy of three-phase bone scans in evaluating diabetic foot ulcers

To evaluate the utility of bone scans in determining the treatment of diabetic patients with foot ulcers, a retrospective study was conducted. Medical records were reviewed for clinical signs of infection, laboratory data, and the radiologists' interpretations of imaging studies. During the study period, 34 bone scans were obtained by the treating physicians to evaluate diabetic foot ulcers. Among these, 22 of 34 bone scans were markedly confirmatory of being "consistent with osteomyelitis," 8 of 34 were moderately confirmatory ("indeterminate with regard to osteomyelitis"), and 4 of 34 were not confirmatory ("not consistent with osteomyelitis"). Of the 22 patients in the markedly confirmatory group, eight patients with clinical findings of uncontrolled infection or gangrene were treated with partial or complete amputation, whereas all others (14 patients) were treated with local wound care+/-intravenous antibiotics. Among the eight bone scans interpreted as indeterminate, three patients required partial or complete amputation, whereas the other five patients were managed with local wound care. Of the four patients with nonconfirmatory bone scans, two patients had evidence of dry gangrene and required amputation, whereas the other two patients did not have clinical evidence of infection or gangrene and were treated with local wound care. There was no significant difference in the amputation rate for patients with confirmatory, indeterminate, or nonconfirmatory bone scans for osteomyelitis (36%, 37%, and 50%, respectively) (P > 0.5). Therefore, the authors concluded that the ultimate treatment should be based on clinical indicators of the presence of uncontrolled infection or gangrene rather than on bone scan findings.

Adult posttraumatic osteomyelitis of the tibia

Posttraumatic tibial osteomyelitis results from trauma or nosocomial infection from the treatment of trauma that allows organisms to enter bone, proliferate in traumatized tissue, and cause subsequent bone infection. The resulting infection is usually polymicrobial. The patient may be classified using the May and the Cierny-Mader classification systems. The diagnosis is based on the isolation of the pathogen(s) from the bone, or blood cultures. Appropriate therapy of posttraumatic tibial osteomyelitis includes adequate drainage, thorough debridement, obliteration of dead space, stabilization when necessary, wound protection, and specific antimicrobial therapy.

Detection of osteomyelitis in the neuropathic foot: nuclear medicine, MRI and conventional radiography

The diagnostic efficacy of (1) combined three-phase bone scintigraphy and In-111 labeled WBC scintigraphy (Bone/WBC), (2) MRI, and (3) conventional radiography in detecting osteomyelitis of the neuropathic foot was compared. Conventional radiography was comparable to MRI for detection of osteomyelitis. MRI best depicted the presence of osteomyelitis in the forefoot. Particularly in the setting of Charcot joints, Bone/WBC was more specific than conventional radiography or MRI.