Prognostic value of 99m Tc leukocyte scintigraphy in diabetic pedal osteomyelitis

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.

Application of white blood cell SPECT/CT to predict remission after a 6 or 12 week course of antibiotic treatment for diabetic foot osteomyelitis

AIMS/HYPOTHESIS

Diabetic foot osteomyelitis is a major risk factor for amputation. Medical treatment allows remission in 53-82% of cases. However, the optimal duration of antibiotic therapy remains controversial as a validated marker of osteomyelitis remission is lacking. The aim of this cohort study was to assess prospectively the remission rate of diabetic foot osteomyelitis medically treated using white blood cell (WBC)-single-photon emission computed tomography (SPECT)/computed tomography (CT) as a predictive marker of remission.

METHODS

Individuals with diabetic foot osteomyelitis that was non-surgically treated between April 2014 and December 2015 were included. All participants were treated with antibiotics alone. WBC-SPECT/CT was performed at 6 weeks and antibiotic treatment discontinued if the clinical signs of soft-tissue infection had resolved and there was no abnormal uptake of labelled WBCs. Treatment was otherwise continued for a total of 12 weeks and then discontinued. For these individuals, another WBC-SPECT/CT was performed at 12 weeks. Remission was defined as the absence of recurrence of osteomyelitis at the same location at 1 year.

RESULTS

Forty-five individuals were included; overall remission rate was 84% at 1 year. A 6 week course of antibiotics was used in 23 participants, 22 of whom were in remission at 1 year (96%); a 12 week course was used for 22 participants, 16 of whom were in remission at 1 year (73%). Sensitivity of WBC-SPECT/CT at 12 weeks was 100%, specificity 56%, positive predictive value 46% and negative predictive value 100%.

CONCLUSIONS/INTERPRETATION

The study suggests that WBC-SPECT/CT could predict remission at the end of antibiotic treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02927678.

Scintigraphic Evaluation of the Stump Region After Extremity Amputation and the Effect of Scintigraphy on Treatment

Background

We evaluated the stump region with scintigraphy and compared the correlation of treatment modalities and scintigraphic results.

Methods

Sixty-eight cases with extremity amputation were included in the study. Amputation applied cases underwent four-phase Tc-99m hydroxymethylene diphosphonate scintigraphy. Groups were performed according to the scanning time after amputation and amputation regions. After scintigraphic evaluation, results were recorded into five groups: osteomyelitis, soft-tissue infection, reactive changes secondary to surgery, chronic osteomyelitis, and normal. Post-surgical treatment modalities of the patients were determined and compared with scintigraphic results.

Results

In the scintigraphic evaluation of stump regions of the 68 amputated cases, 34 patients had acute osteomyelitis, one had chronic osteomyelitis, 16 had soft-tissue infection, and eight had changes secondary to the surgery. Nine of 68 cases had normal scintigraphic features. In the scintigraphic evaluation, 43 patients took antibiotic treatment and 16 had surgery. There was a strong correlation between scintigraphic results and treatment approach (P < 0.0001, r = 0.803) by means of preferred therapy and effectiveness of the therapy according to the scintigraphic results. Scintigraphy need increases with age after amputation and a negative correlation between patient age and scintigraphic need was found (P < 0.02, r = -0.339). There was no pathology in the follow-up in the cases that were scintigraphically normal.

Conclusion

Bone scintigraphy is a cost-effective, non-invasive, and efficient method that directs treatment in the evaluation of the stump region after amputation.

Assessing diabetic foot osteomyelitis remission with white blood cell SPECT/CT imaging

AIMS

Diabetic foot osteomyelitis is an important risk factor of lower limb amputation. Antibiotic therapy is often effective in preventing surgery. However, the duration of antibiotic therapy is difficult to define in the absence of a marker to diagnose osteomyelitis remission at the end of the treatment. In this study, we assessed the diagnostic performance of white blood cell SPECT/CT imaging for evaluating osteomyelitis remission.

PATIENTS AND METHODS

Twenty-nine out of 42 episodes of diabetic foot osteomyelitis seen between December 2009 and April 2012 had radiographs, a three-phase bone scintigraphy and a white blood cell SPECT/CT at the end of antibiotic therapy. They were treated with antibiotics alone and considered in clinical remission. White blood cell SPECT/CT results were considered positive when abnormal uptake in the osteomyelitis location was identified. Osteomyelitis remission was defined by the absence of an osteomyelitis relapse after 12 months' follow-up.

RESULTS

A negative white blood cell SPECT/CT was seen for 22 episodes of osteomyelitis. All of them were in remission. A positive white blood cell SPECT/CT was observed for seven episodes. A relapse occurred in five episodes (71.5%) after a median duration of 4 months (2-7 months). Sensitivity, specificity, positive predictive value and predictive negative value in predicting osteomyelitis relapse after the discontinuation of antibiotic treatment were, respectively, for radiographs 80%, 33%, 20% and 89%; for three-phase bone scintigraphy 100%, 12.5%, 15.5% and 100%; and for the white blood cell SPECT/CT 100%, 91.5%, 71.5% and 100%.

CONCLUSION

Negative uptake on white blood cell SPECT/CT is a good marker for diagnosis of diabetic foot osteomyelitis remission and might be very useful in guiding antibiotic therapy.

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.

Management of osteomyelitis

Osteomyelitis is an infection of the medullary or cortical bone that is becoming more difficult to cure with the increasing prevalence of methicillin- and vancomycin-resistant organisms. This article discusses the etiology of osteomyelitis and the effectiveness of various treatment options.