MR imaging of chronic osteomyelitis

Diagnostic Efficacy of Diffusion-weighted Imaging in Distinguishing Chronic Diffuse Sclerosing Osteomyelitis from Suppurative Osteomyelitis of the Mandible

PURPOSE

Chronic diffuse sclerosing osteomyelitis (CDSO) is a non-suppurative inflammatory bone disease diagnosed based on combined clinical, histopathological, and radiological findings. Accurate diagnosis is important since CDSO is more refractory to treatment than suppurative osteomyelitis. The purpose of this study was to determine the diagnostic efficacy of diffusion-weighted imaging (DWI) in the quantitative assessment of CDSO to distinguish it from acute suppurative osteomyelitis (ASO) and chronic suppurative osteomyelitis (CSO) of the mandible.

METHODS

Using a retrospective cohort study design, we analyzed MRI data of 6 patients with CDSO and 34 patients with ASO and CSO. The mean apparent diffusion coefficient (ADC) values of the three groups (CDSO, ASO, and CSO groups) were calculated, and differences were analyzed using Kruskal-Wallis and post-hoc Mann-Whitney tests with Bonferroni adjustments. We performed a receiver operating characteristic (ROC) curve analysis to evaluate the ability of the ADC to predict CDSO. P < 0.05 was considered statistically significant.

RESULTS

The mean ADCs in the CDSO, ASO, and CSO groups were 1.22 ± 0.04 × 10-3 mm2/s, 1.28 ± 0.08 × 10-3 mm2/s, and 1.06 ± 0.09 × 10-3 mm2/s, respectively. Significant differences were observed between the ASO and CSO groups (P < 0.001) and CSO and CDSO groups (P < 0.01). However, there was no significant difference between the ASO and CDSO groups (P = 0.21). The ROC analysis revealed a cut-off ADC value of 1.19 for distinguishing the CSO group from the CDSO group. Sensitivity, specificity, accuracy, and area under the ROC curve were 1.0, 0.92, 0, 95, and 0.94, respectively.

CONCLUSION

The results suggest that ADC may be useful in distinguishing CDSO from mandibular suppurative osteomyelitis.

Magnetic resonance imaging texture analysis in the quantitative evaluation of acute osteomyelitis of the mandibular bone

OBJECTIVES

Accurate assessment of radiological images can help in early diagnosis and therapy of suppurative osteomyelitis (OM). The purpose of this study was to apply texture analysis to MRI as a means of quantitatively evaluating acute OM of the mandible.

METHODS

We analyzed the data from 38 patients who complained of pain and underwent MRI between April 2017 and March 2019. From the MRIs of these patients, with (n = 19) and without OM (n = 19), 279 radiomics features were extracted using short tau inversion recovery, data of the regions of interest and analyzed with MaZda v. 3.3. 10 features, including one histogram feature (90th percentile), eight gray-level co-occurrence matrix features (Sum Averg), and one gray-level run-length matrix feature (Horzl_RLNonUni), were selected using Fisher coefficient and compared between the acute OM and non-OM groups. The two groups were compared using Mann-Whitney U test with p value set at 0.05.

RESULTS

All 10 radiomics features showed significant differences between the acute OM and non-OM groups (p < 0.05).

CONCLUSIONS

MRI texture analysis has potential application in radiomics diagnosis of acute OM of the mandible.

Efficacy of diffusion-weighted magnetic resonance imaging in the diagnosis of osteomyelitis of the mandible

OBJECTIVE

This retrospective cohort study aimed to determine the diagnostic utility of apparent diffusion coefficient (ADC) values in the quantitative evaluation of mandibular osteomyelitis.

METHODS

We analyzed the records of 70 patients aged 30 to 90 years, with and without osteomyelitis, who underwent magnetic resonance imaging at the Nihon University School of Dentistry between April 2017 and March 2019. The mean ADC of bone marrow of patients without osteomyelitis and those with acute and chronic osteomyelitis of the mandible were calculated. Differences in ADC overall and in pair-wise comparisons were analyzed. Correlations with patient age were also calculated.

RESULTS

The mean ADC values in the nonosteomyelitis, acute osteomyelitis, and chronic osteomyelitis groups were 0.87 ± 0.15 × 10^-3, 1.24 ± 0.11 × 10^-3, and 1.07 ± 0.13 × 10^-3 mm²/s, respectively (P < .001 for all pair-wise comparisons). Receiver operating characteristic curve analysis revealed an ADC cut-off of 0.98 for osteomyelitis. Diagnostic values for predicting osteomyelitis were ≥ .81. No correlations of osteomyelitis with age were found.

CONCLUSIONS

The ADC was significantly higher in the osteomyelitis groups than in the nonosteomyelitis group. This suggests that ADC may be a useful parameter for quantitative evaluation of mandibular osteomyelitis.

Quantitative assessment of age-related changes in the mandibular bone marrow using apparent coefficient value

PURPOSE

The purpose of this study was to investigate the age-related changes in apparent diffusion coefficient (ADC) values of the mandibular bone marrow using diffusion-weighted imaging (DWI).

MATERIALS AND METHODS

This retrospective cohort study comprised all patients who underwent pantomography and magnetic resonance imaging (MRI) between April 2018 and November 2020 at our institution. A total of 351 participants (140 men, 211 women), aged 15-89 years (mean age 46.01 years), were included in the study. Spearman's correlation coefficients were calculated using age groups as the criterion variable and the ADC values as the explanatory variables. P < 0.05 was considered statistically significant.

RESULTS

The mean ADC value for all age groups was 0.91 ± 0.18 in men and 0.86 ± 0.16 in women (p = 0.016). There was a significant negative correlation between age and the ADC values in each sex group (p < 0.001).

CONCLUSION

This study demonstrates that the normal ADC values of the mandibular bone marrow show significant negative correlation with increasing age. These findings will be useful in the diagnosis of bone marrow diseases.

Septic arthritis in children: frequency of coexisting unsuspected osteomyelitis and implications on imaging work-up and management

OBJECTIVE

Osteomyelitis and septic arthritis clinically present at any age with overlapping signs and symptoms. The purposes of this study were to evaluate the demographic distribution of septic arthritis and osteomyelitis in children and to explore optimal imaging guidelines for these patients.

MATERIALS AND METHODS

We performed a retrospective study of children up to 18 years old who were treated for osteomyelitis or septic arthritis between January 2011 and September 2013. All patients underwent MRI without previous intervention. Studies were reviewed to determine the incidence of septic arthritis or superimposed osteomyelitis. The reference diagnosis was based on the combined review by the orthopedic surgeon and infectious disease notes, discharge summary, operative report, and MRI examination.

RESULTS

One hundred sixty-two children who underwent 177 MRI examinations were diagnosed with acute musculoskeletal infection. One hundred three patients were included in the septic arthritis category, of whom 70 (68%) had septic arthritis with osteomyelitis. Seventy-four (42.1%) patients had isolated osteomyelitis without septic arthritis. Children under 2 years old were more likely to have septic arthritis (either isolated or with osteomyelitis) than isolated osteomyelitis compared with older children (p = 0.0003).

CONCLUSION

In children who underwent MRI for suspected musculoskeletal infection, septic arthritis was more prevalent in children under the age of 2 years than in older children. However, both septic arthritis and osteomyelitis were found frequently in older children. Musculoskeletal infection imaging workup guidelines for children of all ages should address the frequent association of osteomyelitis and septic arthritis. We recommend that MRI should be used in the evaluation of suspected musculoskeletal infections in children, and the nearest joint should always be included to evaluate the extent of articular disease.

MR imaging of the paediatric foot and ankle

Radiography is the mainstay for initial evaluation of paediatric foot and ankle pathology. MRI is the preferred exam for further characterisation of the majority of these conditions. The modality features high sensitivity and specificity for this purpose with few exceptions. Findings on MRI will often dictate patient referral and further management, and are frequently required for surgical planning. This article will provide an overview of a variety of pathologies that afflict the foot and ankle in children. These include tarsal coalition, osteochondral lesions, osteonecrosis, osteochondroses, stress fractures, osteomyelitis, inflammatory arthritis, neoplasms of bone and soft tissue, and foreign bodies. Their respective imaging manifestations on MRI are the focus of the paper. Technical parameters and marrow signal variation are also discussed.

Diagnosis of tuberculous vertebral osteomyelitis (TVO) in a developed country and literature review

STUDY DESIGN

Review of medical and radiological records and literature to study the diagnosis of tuberculous vertebral osteomyelitis (TVO) and the differential diagnosis between TVO and pyogenic vertebral osteomyelitis (PVO).

OBJECTIVE

To identify the correct criteria for the diagnosis.

SETTING

National Spinal Injuries Centre, UK.

METHODS

(1) Medical and radiological records of 10 patients diagnosed as vertebral osteomyelitis and treated elsewhere but later admitted to the NSIC were reviewed retrospectively. (2) Medical literature on vertebral osteomyelitis were reviewed.

RESULTS

(1) Case review: Before the study, four of the 10 patients TVO had been diagnosed based on positive bacteriology. Of the other six, the diagnosis of PVO had been made in one based on positive blood culture of staphylococcus while in another without any positive result of bacteriology. The diagnosis had been uncertain in four because of negative results of both bacteriology and histology on both tuberculous and pyogenic infection. The author made the diagnosis of TVO in all 10 cases based on clinical manifestations and plain radiographs. Highly raised ESR with moderate rise of or normal WBC in eight cases supported TVO. Computer tomography and magnetic resonance imaging did not contribute to the differential diagnosis. Laminectomy in five patients led to some clinical improvement. The five patients without surgery deteriorated. Two of them died. (2) LITERATURE REVIEW: A total of 188 articles were reviewed. The crucial role of plain radiographs in the diagnosis of TVO and the high incidence of false-negative of tuberculosis in both bacteriological and histological tests were neglected in most articles. Polymerase chain reaction (PCR) was more reliable in diagnosing tuberculosis.

CONCLUSION

Clinical manifestations, discrepancy between ESR and WBC, plain radiographs and PCR are keys to a correct diagnosis of TVO.

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.

Subacute osteomyelitis of long bones: diagnostic usefulness of the "penumbra sign" on MRI

Although subacute osteomyelitis of long bones is not uncommon, it is usually confined to metaphysis. Two unusual cases of subacute osteomyelitis that traversed a growth plate are described. There may be some radiological difficulties in distinguishing it from other malignant or benign lesions. On magnetic resonance (MR) imaging, both of the present cases showed characteristic four-layered appearance and the penumbra sign. These characteristic findings on MR imaging are considered to facilitate establishing the radiologic diagnosis.

Imaging of osteomyelitis in the mature skeleton

Diagnosis of acute osteomyelitis is often challenging but can be made by plain radiograph, bone scan, or MR imaging. This diagnosis may be more problematic in small bones, in diabetic or immunocompromised patients, those partially treated, post-traumatic, previous surgery, or with pre-existing marrow conditions and associated soft tissue infections. CT is the modality of choice for revealing sequestra and cortical erosions in chronic osteomyelitis. Nonenhanced and enhanced STIR or fat-saturated sequences are essential to reveal the marrow abnormality and its extension for diagnosis of subtle cases with neuropathic or other associated conditions. Combined radionuclide scintigraphy becomes necessary in complicated situations.

Nuclear medicine imaging in early vertebral osteomyelitis: still of clinical utility

A case is presented of vertebral osteomyelitis in an elderly confused patient with poorly localizing signs. The lesion was not diagnosed on the initial MRI study of the spine due to poor targeting. The abnormality was detected on a bone scan the following day. This was confirmed with a gallium scan 3 days later, and also a repeat MRI study 11 days after the first MRI, using an optimized protocol over the region of interest established by the bone scan.

Infection: ultrasound-guided procedures

The majority of fluid collections in the musculoskeletal system can be localized and aspirated under ultrasound guidance. Whether fluid is infected cannot be determined from ultrasound appearances and laboratory analysis is required. In complicated infection, particularly septic arthritis and osteomyelitis, combined use of MR imaging and aspiration under ultrasound is very useful.

MRI in patients with intraspinal bullets

The purpose of this study was to determine whether neurologic sequelae occur in patients with intraspinal bullets or bullet fragments who undergo magnetic resonance imaging (MRI). Nineteen patients with bullets or bullet fragments adjacent to the cord or nerve roots underwent clinical MRI studies at 1.5 T. Sequences included conventional spin echo, fast spin echo, gradient-recalled echo, and inversion recovery. Patients were queried during scanning for symptoms of discomfort, pain, or change in neurologic status. Detailed neurologic examinations were performed prior to MRI (baseline), post MRI, and at the patients' discharge. Sixteen patients were completely paralyzed (ASIA-A), and three were not paralyzed. The length of time from injury was 2-24 months. No patients experienced pain or discomfort during the procedure. No change in neurologic status occurred. Follow-up radiographic studies showed no bullet movement following the scanning. We conclude that in patients with complete spinal cord injury, MRI in patients with intraspinal bullets may be performed.

Osteomyelitis of the pelvis/hips in paralyzed patients: accuracy and clinical utility of MRI

PURPOSE

The goal of our study was to determine the accuracy and clinical utility of MRI in the diagnosis of osteomyelitis of the pelvis/hips in paralyzed patients.

METHOD

In 44 paralyzed patients, 59 consecutive MR examinations of the pelvis/hips were evaluated prospectively. Criteria for diagnosis of osteomyelitis were based on those established in previous studies of complex, nonhematogenous osteomyelitis (diabetic foot). Average follow-up was 3 years. The standard of reference for the diagnosis of osteomyelitis was histologic/microbiologic results of surgical biopsy specimens or clinical follow-up. Note was made if decubitus ulcers, sinus tract, fistula, fluid collection, abscess, septic arthritis, joint effusion, bursitis, or heterotopic ossification was present on MRI. Comparison of the extent of infection by MRI and surgical margins was performed. Effect on surgical treatment was defined by absence of recurrent infection at the surgical site within 6 weeks of limited resection.

RESULTS

The criteria for diagnosis of osteomyelitis were fulfilled in 49 of 57 MR studies for an overall accuracy of 97%. There was one false-negative MR study. MRI for the diagnosis of osteomyelitis yielded a sensitivity of 98% and a specificity of 89%. There were 41 decubitus ulcers, 28 sinus tracts, 2 fistulae, 14 fluid collections, 15 abscesses, 9 hips with septic arthritis, 10 "bland" hip effusions, 5 cases of trochanteric bursitis, and 30 patients with heterotopic ossification. Twenty-one patients underwent limited surgical resection guided by MR findings in which only the enhancing area was resected. There was only one recurrence of osteomyelitis at the surgical margins.

CONCLUSION

MRI is accurate in the diagnosis of osteomyelitis and associated soft tissue abnormalities in spinal cord-injured patients. MRI can delineate the extent of infection in guiding limited surgical resection and preserving viable tissue.

Update on imaging of orthopedic infections

Although the diagnosis of infection is only a small part of the orthopedist's job description, it is a important part. This article discusses the fundamentals of orthopedic infections and highlights the refinements on this topic from a radiologic perspective. In addition to reviewing the imaging appearance of musculoskeletal infections in bone and the surrounding soft tissues, we focus on the advantages and disadvantages of five imaging methods: radiography, sonography, CT, scintigraphy, and MR imaging. Finally, we review three specific situations that have garnered substantial attention in recent medical literature: chronic recurrent multifocal osteomyelitis, musculoskeletal infections in AIDS patients, and pedal infections in diabetic patients.

Surgical management of nontuberculous thoracic and lumbar vertebral osteomyelitis: report of 33 cases

BACKGROUND

Thirty-three patients with nontuberculous pyogenic thoracic and lumbar vertebral osteomyelitis were treated surgically. Indications for surgery were either progression of disease despite adequate antibiotic therapy, neurologic deficit, or both. The most common initial symptom was back pain. Seven patients had diabetes, seven patients were intravenous drug users, two patients were receiving immunosuppressive therapy, and seven patients had a debilitating disease. Eleven had infections elsewhere in their bodies. Prior to surgery organisms were grown from blood in 10 patients and at surgery in 15 patients.

METHODS

Infection was evident on plain films in all patients, and either a CT scan or MRI was obtained in each. The lateral extracavitary approach was used for resection of granulation tissue and infected bone ventral to the dura. Interbody bone grafts were placed in 19 patients, usually when bone resection was extensive. Posterior instrumentation was placed in 17 patients at a second procedure 10 days-2 weeks following initial operation. Intravenous antibiotics were administered for 4-6 weeks following surgery, and solid fusion was obtained in all patients.

RESULTS

Neurologic deficit was present in 28 patients prior to surgery and was functionally significant in 18 patients. Of the 11 patients with severe paraparesis, 10 achieved good functional recovery. These patients were able to walk, three with assistance and seven without, and all those who were unable to void regained this ability.

CONCLUSIONS

Surgical debridement, interbody fusion, and posterior instrumentation is a safe and effective treatment for vertebral osteomyelitis and is indicated when neurologic deficit or bone destruction progress despite adequate antibiotic therapy.

Chronic recurrent multifocal osteomyelitis involving both jaws: report of a case including magnetic resonance correlation

A case of chronic recurrent multifocal osteomyelitis in a 14-year-old girl is presented. The disease had an initial aggressive osteolytic appearance involving both the maxilla and the mandible. Conservative treatment with minimal surgical intervention has been successful in this case during a 2-year follow-up period. The value of magnetic resonance imaging and bone scintigraphy in this case and the cause of chronic recurrent multifocal osteomyelitis is discussed.

Multimodality imaging of osteomyelitis

Early diagnosis of osteomyelitis continues to be a clinical problem. Multiple imaging modalities are being used for the diagnosis of osteomyelitis, but none of them is ideal for all cases. The choice of modality depends on several factors based on an understanding of the pathophysiologic aspects of different forms of osteomyelitis. After a brief introduction outlining some basic principles regarding the diagnosis of osteomyelitis, pathophysiologic aspects are reviewed. Advantages and disadvantages of each imaging modality and their applications in different forms of osteomyelitis are discussed. The use of different imaging modalities in the diagnosis of special forms of osteomyelitis, including chronic, diabetic foot, and vertebral osteomyelitis, and osteomyelitis associated with orthopedic appliances and sickle cell disease is reviewed. Taking into account the site of suspected osteomyelitis and the presence or absence of underlying pathologic changes and their nature, an algorithm summarizing the use of various imaging modalities in the diagnosis of osteomyelitis is presented.

Magnetic resonance imaging of osteomyelitis in the mandible. Comparative study with other radiologic modalities

Magnetic resonance imaging of 14 histopathologically confirmed cases of osteomyelitis of the mandible was retrospectively reviewed. The findings of magnetic resonance imaging were compared with conventional radiography, computed tomography, bone scintigraphy, and histopathologic examinations. All lesions in bone marrow were shown as areas of low (64%) or low-to-intermediate (36%) signal intensity on T1-weighted images, and areas of high (29%), mixed (high and low, 21%; high and intermediate, 36%) or low (14%) signal intensity on T2-weighted images. Histopathologically, high T2-weighted signal intensity areas that showed enhancement after contrast injection corresponded to active infection. These were not collections of pus but were predominantly areas of granulation tissue. Magnetic resonance imaging showed larger areas of abnormality than plain radiography or computed tomography. Bone scintigraphy did not accurately reveal the locations of lesions but showed heterogeneous increased uptake in all patients. MRI was an extremely useful technique for assessing osteomyelitis of the mandible.

Magnetic resonance imaging for the diagnosis of osteomyelitis in the diabetic patient with a foot ulcer

Twenty-seven diabetic patients (12 males and 15 females) with clinically suspected osteomyelitis complicating soft tissue infection of the foot underwent 29 magnetic resonance imaging studies of the suspected lesion. Of these patients, 26 had plain film radiographs, 11 had technetium bone scanning, and 12 had indium-labeled leukocyte scintigraphy performed within 2 weeks of the magnetic resonance imaging. Definitive diagnosis of the presence or absence of osteomyelitis was obtained on the basis of surgical findings, histological evidence, or resolution with nonoperative therapy. Magnetic resonance imaging was 90% accurate (sensitivity 77%, specificity 100%) in the diagnosis of osteomyelitis in this patient population. Technetium bone scan was 45% accurate (sensitivity 100%, specificity 25%); indium-labeled leukocyte scintigraphy was 50% accurate (80% sensitivity, 29% specificity); and plain film roentgenography was 73% accurate (60% sensitivity, 81% specificity). Magnetic resonance imaging is a powerful, noninvasive tool for determining the presence or absence of osteomyelitis in the patient with a diabetic foot ulcer.

Brodie abscess: MR imaging appearance in 10 patients

The magnetic resonance (MR) imaging features of Brodie abscess have not yet been fully evaluated. Ten patients with Brodie abscess, eight of long bone and two of vertebra, were studied with MR imaging. Long bone abscess had a characteristic "target" appearance with four layers: (a) a center with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR (short-inversion-time inversion recovery) images, (b) an inner ring isointense to muscle on T1-weighted images and with high signal intensity on T2-weighted and STIR images, (c) an outer ring hypointense on all images, and (d) a peripheral halo hypointense on T1-weighted images. In six of eight cases, a soft-tissue mass was found. The two vertebral abscesses had a less specific appearance, with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR images. Only the peripheral halo was clearly identified in both cases.

Evaluation of magnetic resonance imaging in the diagnosis of osteomyelitis in diabetic foot infections

To assess the role of magnetic resonance imaging (MRI) in diagnosing osteomyelitis in diabetic foot infections, 47 diabetic patients with clinical suspicion of osteomyelitis, nonhealing foot ulcer, or soft tissue infection of the foot were examined prospectively by MRI and plain radiographs. Pathological confirmation of diagnosis was obtained in 62 bones from 32 patients. In addition, 14 patients with pathological confirmation of diagnosis underwent technetium-99 MDP triple-phase bone and gallium-67 citrate scans. MRI was significantly more sensitive and accurate (P < .01), with equal specificity in comparison to plain radiographs and technetium and gallium scans. MRI also provided a more detailed and accurate depiction of the anatomy. At early clinical follow-up, complete resection of abnormal bone on an MRI scan correlated with clinical healing. In summary, MRI is indicated when plain radiographs are negative for osteomyelitis or when the extent and accurate depiction of the infective process will facilitate surgical planning.

Pyogenic osteomyelitis of the spine in the elderly

The authors report 10 cases of spontaneous pyogenic spinal osteomyelitis encountered within a 3-year period. There were six women and four men, ranging in age from 60 to 84 years. Six cases occurred at the thoracic level, three at the lumbar level, and one in the cervical spine. No patient was diabetic, immunocompromised, or receiving steroid therapy, and none had a history of endocarditis or intravenous drug abuse. No patient had undergone previous spinal surgery. There were no instances of coexisting tuberculosis or malignancy. Contemporaneous cases with known predisposing factors have been excluded from this report; however, three patients did have a recent history of somatic infection, one with known sepsis. All 10 patients had been previously misdiagnosed, frequently by neurosurgeons and orthopedists as well as by internists and family practitioners. Three had undergone inappropriate or unnecessary surgical procedures, and two had received inappropriate radiation therapy. Seven cases were caused by Staphylococcus species. Gram-negative bacteria, or anaerobic infections. In the other three, no bacteriological diagnosis was made, secondary to prolonged antibiotic therapy before surgery. Each patient had developed symptomatic neural element compression, spinal instability, or both by the time of their referral. The patients with subcervical pyogenic spinal osteomyelitis underwent transthoracic or retroperitoneal decompression and corpectomy with simultaneous autologous bone grafting, followed by 6 weeks of bed rest and 6 weeks of intravenous broad-spectrum or organism-specific antibiotic therapy. They were then mobilized in orthoses for an additional 6 weeks. In no case were foreign implants employed or further stabilization procedures necessitated. One patient required an additional 6 weeks of antibiotics for recalcitrant Pseudomonas colonization. Despite the patients' advanced age and the extensive surgical procedures, there was no mortality and no neurological morbidity. All patients were asymptomatic or demonstrated objective improvement upon discharge from the hospital. In this subset of patients with spontaneous pyogenic vertebral osteomyelitis, the only predisposing factor was advanced age.

Osteomyelitis: sensitivity of 0.064 T MRI, three-phase bone scanning and indium scanning with biopsy proof

We compared the ability of magnetic resonance imaging (MRI) using a 0.064 T permanent magnet, three-phase bone scanning, and indium-labeled white blood cell (111In-WBC) scanning, to diagnose osteomyelitis. Twenty-three patients underwent biopsy. All patients were examined at presentation with all three modalities. Sensitivities for each modality were calculated using biopsy as a gold standard. The results were 72% for MRI, 68% for bone scan, and 45% for 111In-WBC. Specificities were not calculated because of lack of negative biopsies. MRI was as sensitive as bone scanning in the diagnosis of osteomyelitis. All modalities had lower than previously reported sensitivities for imaging osteomyelitis.

Septic arthritis of the sternoclavicular joint in healthy adults

Septic arthritis of the sternoclavicular joint (SCJ) is a rare disorder, and is usually associated with predisposing factors such as contiguous foci of infection, heroin addiction, rheumatoid arthritis and diabetes mellitus. Three cases in previously healthy adults are reported here. The aetiology, clinical manifestations and treatment are briefly reviewed. The considerable difficulty in diagnosing this disorder in adults is emphasized. In summary, diagnosis of septic arthritis of the SCJ in adults requires a high index of suspicion, and must be considered not only in patients with predisposing factors, but also in previously healthy adults.

Skeletal complications of type I Gaucher disease: the magnetic resonance features

Abnormalities on magnetic resonance imaging (MRI) are reported in six individuals with various skeletal complications of type I Gaucher disease. The changes were a nonhomogeneous reduction in both T1 and T2 marrow signals with increased T2 signals during avascular episodes. MRI proved an excellent technique for the assessment of bone marrow changes in Type I Gaucher disease and for assessing avascular complications. It was not able to differentiate between pseudo-osteomyelitis and pyogenic osteomyelitis without clinical correlation. The problems studied included the extent of intramedullary Gaucher cell infiltration, avascular necrosis of femoral heads, assessment of bone pain from pseudo-osteomyelitis and the relationship of skeletal disease to splenectomy.