Diagnostic performance comparison of conventional radiography to magnetic resonance imaging for suspected osteomyelitis of the extremities: a multi-reader study.

OBJECTIVE: To determine whether MRI provides improved diagnostic accuracy compared to radiography for the diagnosis of extremity osteomyelitis (OM) with multi-reader analysis. METHODS: In this cross-sectional study, three musculoskeletal fellowship-trained expert radiologists evaluated cases of suspected OM in two rounds-first using radiographs (XR), then with conventional MRI. Radiologic features consistent with OM were recorded. Each reader recorded individual findings on both modalities and rendered a binary diagnosis along with certainty of final diagnosis on a confidence scale of 1-5. This was compared with the pathology-proven diagnosis of OM to determine diagnostic performance. Intraclass correlation (ICC) and Conger's Kappa were used for statistics. RESULTS: XR and MRIs of 213 pathology proven cases (51.5 years ± 14.0 years, mean ± St.Dev.) were included in this study, with 79 tested positive for OM and 98 were positive for a soft tissue abscess, with 78 patients being negative for both. In total, 139 were males and 74 females with bones of interest in the upper and lower extremities in 29 and 184 cases, respectively. MRI showed significantly higher sensitivity and negative predictive value than XR (p < 0.001 for both metrics). Conger's Kappa for OM diagnosis were 0.62 and 0.74 on XR and MRI, respectively. Reader confidence improved slightly from 4.54 to 4.57 when MRI was used. CONCLUSIONS: MRI is a diagnostically more effective imaging modality than XR for finding extremity osteomyelitis with better inter-reader reliability. CLINICAL RELEVANCE STATEMENT: This study validates the diagnosis of OM with MRI over XR but adds novelty because it is the largest study of its kind with a clear reference standard to guide clinician decision making. KEY POINTS: • Radiography is the first-line imaging modality for musculoskeletal pathology but MRI can add value for infections. • MRI shows greater sensitivity for the diagnosis of osteomyelitis of the extremities than radiography. • This improved diagnostic accuracy makes MRI a better imaging modality for patients with suspected osteomyelitis.

Predictive Value of Radiographic and Magnetic Resonance Imaging Characteristics on Patient Outcomes in Confirmed Acute Osteomyelitis of the Extremities.

OBJECTIVE: The aim of this study was to determine whether imaging characteristics on plain radiography, magnetic resonance imaging (MRI), and diffusion-weighted imaging are predictive of patient outcomes in cases of confirmed osteomyelitis (OM). MATERIALS AND METHODS: In this cross-sectional study, 3 experienced musculoskeletal radiologists evaluated pathologically proven cases of acute extremity OM and recorded imaging characteristics on plain radiographs, MRI, and diffusion-weighted imaging. These characteristics were then compared with the patient outcomes after a 3-year follow-up using length of stay, amputation-free survival, readmission-free survival, and overall survival using multivariate Cox regression analysis. Hazard ratio and corresponding 95% confidence intervals are reported. False discovery rate-adjusted P values were reported. RESULTS: For the 75 consecutive cases of OM in this study, multivariate Cox regression analysis adjusting for sex, race, age, body mass index, erythrocyte sedimentation rate, C-reactive protein, and white blood cell count showed no correlation among any of the recorded characteristics on imaging and patient outcomes. Despite the high sensitivity and specificity of MRI for diagnosing OM, there was no correlation between MRI characteristics and patient outcomes. Furthermore, patients with coexistent abscess of the soft tissue or bone with OM had comparable outcomes using the previously mentioned metrics of length of stay, amputation-free survival, readmission-free survival, and overall survival. CONCLUSION: Neither radiography nor MRI features predict patient outcomes in extremity OM.

Incremental value of diffusion weighted imaging over conventional MRI for the diagnosis of osteomyelitis of extremities.

OBJECTIVE: To determine the incremental value of diffusion weighted imaging (DWI) over conventional MR imaging in diagnosing extremity osteomyelitis (OM). MATERIALS AND METHODS: In this cross-sectional study, three experienced musculoskeletal radiologists evaluated clinically suspected cases of extremity OM in two rounds-first on conventional MR imaging, and then conventional MR imaging combined with DWI 4-6 weeks later. The readers recorded a result of the presence or absence of OM and their diagnostic confidence on a 1-5 scale. Mean and minimum apparent diffusion coefficient (ADC) were measured. Pathology diagnosis served as the reference standard. Statistical analysis utilized intraclass correlation (ICC) and Conger's kappa. RESULTS: A total of 213 scans of suspected OM were reviewed by three musculoskeletal radiologists with no significant changes in sensitivity (0.97, 0.97), specificity (0.97, 0.94), positive predictive value (0.91, 0.87), or negative predictive value (0.98, 0.98) between conventional MR imaging and MR imaging combined with DWI, respectively. Reader confidence did not significantly change with the addition of DWI (4.55 and 4.70, respectively). A high inter-reader agreement was observed for the diagnosis of OM, soft tissue abscess, and intraosseous abscess in both rounds. A higher mean (1.46+/-0.43 × 10-3 mm2/s > 0.64+/-0.47 × 10-3mm2/s) and minimum (1.18+/-0.45 × 10-3mm2/s > 0.37+/-0.44 × 10-3mm2/s) ADC value was associated with OM (p-value < 0.0001) with odds ratios of 1.34 and 1.31, respectively, for mean and minimum ADC of the involved bone. CONCLUSION: DWI-derived ADC increase is associated with OM. The use of DWI slightly increases reader confidence in the diagnosis of OM; however, no significant incremental value over conventional MR imaging is seen for the final diagnosis of OM.

Role of magnetic resonance neurography in intercostal neuralgia; diagnostic utility and efficacy.

OBJECTIVE: To evaluate the utility and efficacy of MR neurography (MRN) in the diagnostic work-up for intercostal neuralgia and to assess the treatment course and outcomes in MRN-imaged clinically suspected intercostal neuropathy cases of chronic chest and abdominal wall pain syndromes. METHODS: Following a retrospective cross-sectional study, a consecutive series of patients who underwent MRN of torso for suspected intercostal neuralgia were included. Patient demographics, pain location/level/duration, previous work-up for the same indication, MRN imaging results, and MRN cost per patient were recorded. An inter-reader reliability assessment was performed on the MRN findings using Cohen's weighted κ analysis. Post-MRN treatment choice, as well as success rates of MRN directed perineural injections and surgical management were also evaluated. RESULTS: A total of 28 patients (mean ± SD age, 48.3 ± 18.0 years, female/male = 3.0) were included. Pain and/or numbness in the right upper quadrant were the most common complaints. The mean maximum pain level experienced was 7.4 ± 2.5 on a 1 (lowest pain level) - 10 (highest pain level) visual analog scale. The duration of pain before MRN work-up was 36.9 ± 37.9 months. The patients had seen an average of 5 ± 2.8 physicians for such syndromes. 20 (71%) patients had one or multiple other imaging studies for prior work-up. MRN identified positive intercostal nerve abnormality in 19 cases with clinical symptoms of intercostal neuralgia. From the inter-reader reliability assessment, a Cohen's weighted κ value of 0.78 was obtained. The costs of work-up was about one-third with MRN for diagnostic purposes with less financial and psychological harm. Among the MRN-positive cases, 9/19 patients received perineural injections, of which 6 reported improvement after their first round, lasting an average of 41.1 ± 83 days. Among the nine MRN-negative cases, two received perineural injections, of which none reported improvement. Surgical management was mostly successful with a positive outcome in six out of seven operated cases (85.7%). CONCLUSION: MRN is useful in diagnostic algorithm of intercostal neuralgia and MRN-positive cases demonstrate favorable treatment response to perineural injections and subsequent surgical management. ADVANCES IN KNOWLEDGE: The use of MRN in intercostal neuralgia is an application that has not been previously explored in the literature. This study demonstrates that MRN offers superior visualization of pathology in intercostal neuralgia and confirms that treatment directed at MRN identified neuropathy results in good outcomes while maintaining cost efficiency.

Percutaneous CT guided bone biopsy for suspected osteomyelitis: Diagnostic yield and impact on patient's treatment change and recovery.

AIM: To evaluate the utility of percutaneous CT guided bone biopsy (PCBB) for suspected osteomyelitis (OM) and its eventual impact on patient management and recovery. MATERIAL AND METHODS: Patients who received a PCBB for suspected osteomyelitis from years 2012-2018. Patient demographics, lesion location, ulcer grade, signs of toxemia, serology, wound and blood cultures, bone biopsy and cross-sectional imaging results were recorded. Diagnostic yield of the bone biopsy and its role in influencing the final treatment plan and patient recovery were evaluated. Chi-square test was used. P-value less than 0.05 was considered statistically significant. RESULTS: 115 patients with mean age 50.86 ± 14.49 years were included. The common locations were sacrum/ischium (49/115, 43%) and spine (35/115, 30%). Clinically, 40/115 (35%) had toxemia and 67/115 (58%) had ulcers. Per serology, 17/111 (15%), 95/106 (90%), and 86/98 (88%) had an elevated WBC, CRP, and sedimentation rate, respectively. 22/91 (24%) had a positive blood culture and all 23/23 had a positive wound culture. On imaging, definitive and possible OM were reported in 84.1% and 14.2%, respectively, with 1.8% as no OM. Only 24/115 (21%) had a positive bone biopsy culture and only 10/24 (42%) total positive bone cultures impacted the treatment plan. There was no significant effect of antibiotics on the diagnostic yield of culture (p = 0.08). No statistical significance was found when comparing treatment change based on bone culture results versus all other factors combined (p = 0.33), or when comparing clinical improvement with and without positive bone cultures (p = 0.12). CONCLUSION: Despite positive cross-sectional imaging findings of OM, bone biopsy yield of positive culture is low, and it leads to a small impact in changing the treatment plan or altering the course of patient recovery.

Progenitors in Peripheral Nerves Launch Heterotopic Ossification.

Studies presented here, using a murine model of bone morphogenetic protein type 2 (BMP2)-induced heterotopic ossification (HO) show that the protein initiates HO by signaling through progenitors in the endoneurium of peripheral nerves. In the mouse, these cells were identified in the endoneurium one day after BMP2 induction using antibody against phosphoSMAD (PS) 1, 5, and 8. Studies conducted in a tracking mouse that contains a tamoxifen-regulated Wnt1-Cre recombinase crossed with a td Tomato red (TR) reporter (Wnt1CreErt :Ai9Tm) confirmed their neural origin. In this model both BMP2 induction and tamoxifen are absolutely required to induce TR. SP7+ (osterix+ )TR+ cells were found in the endoneurium on day 1 and associated with bone on day 7. Quantification of TR+ and TR- cells isolated by fluorescence-activated cell sorting showed that all SP7+ cells were found in the TR+ population, whereas only about 80% of the TR+ cells expressed SP7. Pre-chondrocytes (Sox 9+ ) and transient brown fat (tBAT, UCP1+ ) also coexpressed TR, suggesting that the progenitor in nerves is multi-potential. The endoneurium of human nerves near the site of HO contained many PS+ cells, and SP7+ cells were found in nerves and on bone in tissue from patients with HO. Control tissues and nerves did not contain these PS+ and SP7+ cells. Some osteoblasts on bone from patients with HO were positive for PS, suggesting the continued presence of BMP during bone formation. The data suggests that the progenitors for HO are derived from the endoneurium in both the mouse model of HO and in humans with HO. Stem Cells Translational Medicine 2017;6:1109-1119.

Mobile air quality studies (MAQS) in inner cities: particulate matter PM10 levels related to different vehicle driving modes and integration of data into a geographical information program.

BACKGROUND: Particulate matter (PM) is assumed to exert a major burden on public health. Most studies that address levels of PM use stationary measure systems. By contrast, only few studies measure PM concentrations under mobile conditions to analyze individual exposure situations. METHODS: By combining spatial-temporal analysis with a novel vehicle-mounted sensor system, the present Mobile Air Quality Study (MAQS) aimed to analyse effects of different driving conditions in a convertible vehicle. PM10 was continuously monitored in a convertible car, driven with roof open, roof closed, but windows open, or windows closed. RESULTS: PM10 values inside the car were nearly always higher with open roof than with roof and windows closed, whereas no difference was seen with open or closed windows. During the day PM10 values varied with high values before noon, and occasional high median values or standard deviation values due to individual factors. Vehicle speed in itself did not influence the mean value of PM10; however, at traffic speed (10 - 50 km/h) the standard deviation was large. No systematic difference was seen between PM10 values in stationary and mobile cars, nor was any PM10 difference observed between driving within or outside an environmental (low emission) zone. CONCLUSIONS: The present study has shown the feasibility of mobile PM analysis in vehicles. Individual exposure of the occupants varies depending on factors like time of day as well as ventilation of the car; other specific factors are clearly identifiably and may relate to specific PM10 sources. This system may be used to monitor individual exposure ranges and provide recommendations for preventive measurements. Although differences in PM10 levels were found under certain ventilation conditions, these differences are likely not of concern for the safety and health of passengers.