Detection of dysbaric osteonecrosis in military divers using magnetic resonance imaging

This was a controlled cross-sectional study to investigate the prevalence of dysbaric osteonecrosis (DON) in military divers. MRI examinations of the large joints and adjacent bones were performed in a cross-sectional group of 32 highly experienced military divers and 28 non-divers matched for age and anthropometric data. Additional plain radiographs and follow-up controls were performed in all persons with signs certain or suspicious of DON. In two subject groups (one of divers and one of non-divers), lesions characteristic of DON were detected. From this controlled study, it may be concluded that MRI is a highly sensitive method to detect signs of osteonecrosis. It could be shown that the prevalence of bone lesions characteristic of osteonecrosis in highly experienced military divers is not higher than in non-diving subjects of comparable age. The outcome of this comparably small study group fits to the results of previous extensive studies performed with radiographs. The detected low incidence of DON in this collective may be due to the fact that military divers follow stricter selection criteria, decompression schemes and medical surveillance than commercial divers.     

Bone scintigraphy screening for osteonecrosis of the shoulder in patients with non-traumatic osteonecrosis of the femoral head

OBJECTIVE: In patients with non-traumatic osteonecrosis of the femoral head (ONFH), the shoulder is one of the major affected sites secondary to the proximal and distal femur in cases of multiple osteonecrosis. The present study attempted to investigate whether technetium bone scintigraphy is useful for screening of non-traumatic osteonecrosis of the shoulder (ONS). DESIGN AND PATIENTS: A total of 170 shoulder joints in 85 patients with ONFH were evaluated by bone scintigraphy and the findings compared with those of magnetic resonance imaging (MRI). The MR diagnosis was used as the gold standard. RESULTS: Based on the diagnosis by MRI, ONS was detected in 43 shoulders of 27 patients (25%). All necrotic lesions were located in the humeral head. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value of bone scintigraphy for ONS detection were 65%, 81%, 77%, 54% and 87%, respectively. When the necrotic angle of the lesions on the mid-coronal MRI was more than 40 degrees, the sensitivity of bone scintigraphy for ONS detection increased to 88% (21/24 shoulders). CONCLUSION: Bone scintigraphy may be useful for demonstrating medium or large ONS lesions on screening of patients with ONFH.     

Dysbaric osteonecrosis screening in Turkish Navy divers

INTRODUCTION: Dysbaric osteonecrosis (DON) is regarded as an occupational disease for caisson workers, commercial, and military divers. Magnetic resonance imaging (MRI) was suggested for the surveillance of military divers for DON. This study aimed to determine the prevalence of DON in Turkish Navy divers. METHODS: The shoulder, hip, and knee joints of 106 male divers were screened for DON with MRI. A questionnaire was used to obtain information about subjects' medical history and diving experience. RESULTS: The mean age of divers was 34.3 +/- 5.8 yr. The divers had spent an average of 12.1 +/- 6.1 yr at their occupation. The average of total hours of diving was 834 +/- 458 h. The maximum diving depth was 53.0 +/- 18.4 m (175 +/- 61 ft) and the average diving depth was 13.3 +/- 8.4 m (44 +/- 28 ft). MRI examinations of divers did not reveal bone lesions consistent with osteonecrosis. DISCUSSION: We concluded that the risk of DON is very low for military divers who strictly obey the decompression rules and who undergo periodic medical examination. The use of MRI for routine screening of military divers is not justified.     

Osteonecrosis of hip and knee in patients with severe acute respiratory syndrome treated with steroids

PURPOSE: To evaluate whether there is a relationship between steroid treatment and risk for osteonecrosis of the hip and knee in patients with severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: The hospital ethics committee approved the study, and all patients provided written informed consent. A total of 254 patients with confirmed SARS treated with steroids underwent evaluation with magnetic resonance (MR) imaging for osteonecrosis. Clinical profiles, joint symptoms, relevant past medical and drug history, steroid dose, and radiographic and MR imaging evidence of osteonecrosis and other bone abnormalities were evaluated. Mann-Whitney, Kruskal-Wallis, and Pearson exact chi(2) tests were performed, and univariate and multivariate logistic regression analyses were applied. RESULTS: One hundred thirty-four (53%) of 254 patients had recent onset of large joint pain, but 211 (80%) of 264 painful joints were not associated with abnormality on MR images. MR images in 12 (5%) of 254 patients showed evidence of subchondral osteonecrosis in the proximal femur (n = 9), distal femur (n = 2), and proximal and distal femora and proximal tibiae (n = 1). Additional nonspecific subchondral and intramedullary bone marrow abnormalities were present in 77 (30%) of 254 patients. Results of multiple logistic regression analysis confirmed cumulative prednisolone-equivalent dose to be the most important risk factor for osteonecrosis. The risk of osteonecrosis was 0.6% for patients receiving less than 3 g and 13% for patients receiving more than 3 g prednisolone-equivalent dose. No relationship was found between additional nonspecific bone marrow abnormalities and steroid dose. CONCLUSION: An appreciable dose-related risk was found for osteonecrosis in patients receiving steroid therapy for SARS. Additional nonspecific bone marrow abnormalities were frequent. Joint pain was common after SARS infection and was not a useful clinical indicator of osteonecrosis.     

Bone SPECT is more sensitive than MRI in the detection of early osteonecrosis of the femoral head after renal transplantation.

We compared the diagnostic sensitivity of (99m)Tc-methylene diphosphonate bone SPECT and MRI in the early detection of femoral head osteonecrosis after renal transplantation. METHODS: The patients were 24 renal allograft recipients who underwent both bone SPECT and MRI within 1 mo of each other because of hip pain but normal findings on plain radiography. SPECT was considered positive for osteonecrosis when a cold defect was detected in the femoral head, and the defect was further classified according to the presence of adjacent increased uptake: type 1 = a cold defect with no adjacent increased uptake; type 2 = a cold defect with adjacent increased uptake. MRI was considered positive for osteonecrosis when a focal region with low signal intensity on T1 images was detected in the femoral head. Final diagnoses were made by surgical pathology or clinical and radiologic follow-up of >1 y. RESULTS: A total of 32 femoral heads, including 24 of 29 painful hips and 8 of 19 asymptomatic contralateral hips, were confirmed as having osteonecrosis. SPECT detected osteonecrosis in all 32 of the femoral heads, resulting in a sensitivity of 100% (32/32), whereas MRI detected osteonecrosis in 21 femoral heads, for a sensitivity of 66% (21/32, P < 0.005). SPECT showed the type 1 pattern in 13 and the type 2 in 19. Ten of the 13 femoral heads with the type 1 pattern were false-negative on MRI, whereas only 1 of 19 with the type 2 pattern was normal on MRI (P < 0.001). There were 6 femoral heads with normal MRI findings and abnormal SPECT findings (type 1 pattern) in 3 patients, for whom hip pain decreased and radiographic findings were normal during follow-up. Follow-up bone SPECT showed a decreasing area of cold defect in 4 femoral heads. CONCLUSION: (99m)Tc-methylene diphosphonate SPECT is more sensitive than MRI for the detection of femoral head osteonecrosis in renal transplant recipients. Bone scintigraphy with SPECT is needed to diagnose osteonecrosis in patients with hip pain despite normal radiography results after renal transplantation. The significance of a transient SPECT abnormality needs to be clarified by further natural history studies.     

Imaging of primary multifocal osseous lymphoma

 Objective. To review our experience with primary multifocal osseous lymphoma (PMOL), to characterize its imaging features, before and after treatment, and to correlate these features with clinical outcome. Design. Hospital charts and imaging studies of eight patients with PMOL were reviewed. These included bone radiographs, bone scans, CT and MRI. Number, distribution and appearance of lesions before treatment were evaluated; and post-treatment changes were assessed for evidence of healing or progression, correlated with clinical outcome. Results. A total of 63 lesions were identified by pre-treatment bone scan, 36 by MRI (including 10 not visible on bone scan) and 16 by radiographs. Twenty-one percent of lesions occurred about the knee, and 63% of patients had concomitant skull, distal femoral and proximal tibial lesions. The radiographic appearance ranged from lytic to sclerotic. Lesions were isointense to hematopoietic marrow on T2-weighted MR sequences. Only plain radiographic evidence of healing or progression correlated with clinical outcome. Conclusion. Distribution of PMOL was best assessed by bone scan. However, MRI revealed larger areas of marrow involvement and detected lesions in the pelvis not seen on bone scan. Marrow involvement around the knee was common, and the combination of skull, distal femoral and proximal tibial lesions may suggest the diagnosis. Radiographs underestimate the extent of disease but were the best modality for assessment of treatment response.     

Bone marrow edema pattern in advanced hip osteoarthritis: quantitative assessment with magnetic resonance imaging and correlation with clinical examination, radiographic findings, and histopathology

Objective To correlate the amount of bone marrow edema (BME) calculated by magnetic resonance imaging(MRI) with clinical findings, histopathology, and radiographic findings, in patients with advanced hip osteoarthritis(OA). Materials and methods The study was approved by The Institutional Human Subject Protection Committee. Coronal MRI of hips was acquired in 19 patients who underwent hip replacement. A spin echo (SE) sequence with four echoes and separate fast spin echo (FSE) proton density (PD)-weighted SE sequences of fat (F) and water (W) were acquired with water and fat suppression, respectively. T2 and water:fat ratio calculations were made for the outlined regions of interest. The calculated MRI values were correlated with the clinical, radiographic, and histopathologic findings. Results Analyses of variance were done on the MRI data for W/(W + F) and for T2 values (total and focal values) for the symptomatic and contralateral hips. The values were significantly higher in the study group. Statistically significant correlations were found between pain and total W/(W + F), pain and focal T2 values, and the number of microfractures and calculated BME for the focal W/(W + F) in the proximal femora. Statistically significant correlations were found between the radiographic findings and MRI values for total W/(W + F), focal W/(W + F) and focal T2 and among the radiographic findings, pain, and hip movement. On histopathology, only a small amount of BME was seen in eight proximal femora. Conclusion The amount of BME in the OA hip, as measured by MRI, correlates with the severity of pain, radiographic findings, and number of microfractures.     

140 m氦氧饱和-166 m巡回潜水对潜水员骨关节的影响

目的 调查140m氦氧饱和-166m巡回潜水对潜水员骨关节结构和功能的影响。方法 对8名潜水员于潜水前、潜水后半年和1年采用物理检查和MRI检查膝关节，X线摄片检查肩、肘、髋关节并作对照观察。结果 8名潜水员各关节结构和功能正常。结论 在此次大深度饱和潜水中8名潜水员的骨关节功能没有受到明显影响。     

SARS痊愈患者继发骨坏死的临床及MRl分析

目的: 探讨SARS痊愈患者继发骨坏死的临床及MRI表现. 材料和方法: 回顾性分析63例SARS痊愈患者继发骨坏死的MRI表现. 结果: 继发骨坏死者17例,31个骨骼受累,共33个病灶.股骨头20个,股骨下端7个,胫骨上端4个,髌骨2个.结论: SARS痊愈患者继发骨坏死以多骨受累,多发病灶,且表现多样为特点,MRI全面检查,密切随访有症状的骨与关节十分重要.     

Reflex sympathetic dystrophy syndrome. Contribution of magnetic resonance

An attempt was made to establish Magnetic Resonance Imaging (MRI) diagnostic criteria for the study of the reflex sympathetic dystrophy syndrome (RSDS). Five patients with hip and knee pain were studied. The radiographic pattern was "positive" only in two patients, while radionuclide studies showed increased activity in the painful joint in all; only in three cases Computed Tomography was performed. In all patients MRI demonstrates the lesions and defines their extension. MRI allows a differential diagnosis between RSDS and other bone lesions such as osteonecrosis and tumors. The relation between anatomopathological findings of RSDS and MRI features is discussed. MRI proved to be a reliable technique in showing and characterizing RSDS better than radiographic examination (often "negative" in early phases), and radionuclide study (a sensitive but not specific technique).     

SARS康复患者骨坏死改变的MRI筛查

目的　探讨SARS康复患者骨缺血坏死的患病率 ,及其与激素使用的关系。方法　对76例SARS康复患者进行双髋和双膝关节MR扫描。其中男 17例 ,女 5 9例。在治疗SARS时 8例未使用激素 ,其余 6 8例均使用了激素治疗 ,其中 30例有确切激素用量、疗程。对患者全身骨关节症状进行问卷调查。由高年资医生阅读MR图像 ,诊断有无骨缺血坏死改变。对骨缺血坏死患病率、激素用量和症状等参数进行统计学分析。结果　 (1)SARS康复患者股骨头和股骨髁部位出现的骨缺血坏死及骨髓内骨梗死的MRI表现符合临床诊断骨缺血坏死者的MRI典型表现。 (2 ) 8例未用过激素的SARS康复患者无一例出现骨缺血坏死改变 ,而 6 8例使用激素患者中 2 5例出现骨缺血坏死改变 ,两组比较差异有显著性意义 (P <0 0 5 )。 2 5例中有 2 0例累及双侧髋或 (和 )膝关节。骨缺血坏死改变累及股骨头 32个 ,股骨髁 2 6个 ,股骨、胫骨骨髓坏死 6处。在 30例有确切激素用量患者中 ,有骨缺血坏死表现的患者 13例 ,其使用激素总量的中位数为 35 70mg、每日最大用量的中位数为 2 5 0mg、激素使用时间的中位为数 2 3d ,均大于无骨缺血坏死组 (17例 ) ,相应中位数分别为 2 5 6 0mg、2 4 0mg和 2 2d。两组之间 3个参数经秩和检验差异无显著性意义 (P值均 >0 0 5 )     

Dysbaric osteonecrosis screening in submarine escape instructors

INTRODUCTION: Dysbaric osteonecrosis (DON) is an avascular bone necrosis that can be seen in divers and compressed air workers. Submarine escape instructors constitute a specific group who are exposed to hyperbaric conditions with a constant profile. METHODS: We screened 21 Turkish Navy submarine escape instructors and evaluated 147 skeletal radiographs for dysbaric osteonecrosis. Two instructors who had suspicious DON lesions on the X-rays underwent examination by MRI of the suspected sites. RESULTS: We found no evidence of DON in the radiographs and MRIs of the submarine escape instructors. DISCUSSION: We concluded that the risk of DON is very low for submarine escape instructors who work at the Submarine Escape Training Tower (SETT) at a depth of 60 ft and who strictly obey the decompression rules.     

Bone scintigraphy and magnetic resonance imaging after transtrochanteric rotational osteotomy

Objective. To assess the ability of bone scintigraphy and magnetic resonance imaging (MRI) to predict the outcome of transtrochanteric rotational osteotomy (TRO) for osteonecrosis of the femoral head (ONFH). Design. This study was a prospective evaluation of imaging techniques. Patients and methods. MRI and bone scintigraphy were performed on 20 hips in 18 patients at 3 months after TRO. The radiographic findings at 3 months after TRO, and the MRI and bone scintigraphic findings, were compared with the radiographic findings at final follow-up (mean 39 months). Results and conclusions. On MRI a low-intensity area or a low-intensity band in the new weight-bearing area extending over the acetabular edge on T1-weighted images was related to the presence of collapse on the radiographs at final follow-up. In hips with an area of absent activity in the new weight-bearing surface on bone scintigraphy, collapse was seen more frequently on radiographs at final follow-up than in hips without this feature. Bone scintigraphy was no more specific than radiography in predicting the outcome after TRO. We consider MRI to be superior to bone scintigraphy in predicting the occurrence of collapse, which is one of the major short-term problems after TRO. Received: 22 July 1997 Revision requested: 2 January 1998, 12 October 1998 Revision received: 3 March 1998, 23 December 1998 Accepted: 18 January 1999     

Scaphoid nonunions treated with vascularised bone grafts: MRI assessment

Purpose: To assess the value of MR imaging (MRI) with regard to union, graft viability and proximal pole bone marrow status, after use of vascularized bone grafts for treating scaphoid nonunions. Materials and methods: Vascularized bone grafts from the distal radius were used to treat 47 scaphoid nonunions resulting from fractures or enchondromas. Clinical and imaging evaluation was used for the pre- and postoperative assessment of all patients. Apart of conventional radiographs obtained in all cases, 15 patients were also assessed postoperatively with MRI at 3 months. From these 15 patients, eight were assessed preoperatively with MRI whereas nine had serial MRI evaluations at 6 and 12 months. The clinical follow-up time of this subgroup of 15 patients ranged from 6 to 27 months. Results: All patients showed clinical signs of union within 12 weeks form the procedure and at the latest follow-up they experienced complete (10 cases) or almost complete (five cases) relief from pain. Both plain and contrast-enhanced MRI obtained at 3 months showed viability of the bone graft in all cases. At 3 months union was established with plain radiographs in 12 patients at both sides of the graft and in three patients between the graft and proximal pole. At 3 months plain MRI showed nonunion in four patients (two between graft and proximal pole, two between graft and distal pole and one at both sides of the graft) whereas contrast-enhanced MRI revealed only one case of nonunion between graft and proximal pole. Four patients were considered to have osteonecrosis of the proximal pole intraoperatively. Two of them showed necrosis of the proximal pole with preoperative and postoperative plain radiographs and three of them with plain postoperative MRI. Contrast-enhanced MRI at 3 months showed postoperative reversal of necrotic changes in all four scaphoids. MRI also revealed bone marrow oedema of the carpal bones surrounding the scaphoid in 14 cases. Serial MRI at 6 and 12 months, obtained in nine patients, revealed resolution of the bone marrow oedema of the surrounding bones and full graft incorporation in all cases. Conclusion: Contrast-enhanced MRI is able to demonstrate the early union after treatment of scaphoid nonunions with vascularised bone grafts allowing thus earlier mobilisation. In addition, MRI can assess the viability of the proximal pole and the graft as well as the postoperative bone marrow oedema-like lesions of the surrounding bones.     

The application of MR imaging in the detection of hip involvement in patients with ankylosing spondylitis

Objective

To investigate the changes in hip MR imaging, evaluate the frequency of hip involvement and compare the value of clinical symptoms, radiographs, and MR imaging in the detection of hip involvement in patients with ankylosing spondylitis (AS).

Methods

Anteroposterior radiographs of the pelvis, MR imaging of the hip and clinical evaluation were undertaken in 58 patients with definite AS. All patients were followed up 3 years. Annual radiographs and clinical evaluation were carried out. The imaging data were independently assessed by two experienced radiologists who were blinded to patient identity and clinical characteristics. Based on the Bath Ankylosing Spondylitis Radiology Hip Index (BASRI-hip) scoring system, BASRI-hip scores ≥2 were defined as radiological hip involvement. On MR imaging, both acute and chronic inflammatory changes were considered positive signs for hip involvement. Symptomatic hip involvement was defined as current or past pain or limitation of the hip movement. The statistical analysis was performed using the χ² test for comparison of sensitivity among clinical symptoms, radiographs, and MR imaging in the detection of hip involvement and the Student's t-test for comparison of disease duration between with and without hip involvement. A P value <0.05 was considered to be statistically significant. For interpreting MRI and radiographs, the percentage of agreement between the two assessors and the kappa coefficients were calculated.

Results

On MR imaging, positive changes were detected in 86 (74.1%) hips among 116 hips in all 58 patients. Joint effusion was observed in 73 (62.9%) hips; 23 out of 27 patients who underwent fat-saturated contrast-enhanced T₁-weighted sequences had abnormal synovial enhancement in bilateral hips. The other abnormal MR findings included subchondral bone marrow edema in 35 (30.2%) hips, enthesitis in 22 (19.0%) hips, fatty accumulation of the bone marrow in 28 (24.1%) hips, bone erosive destruction in 32 (27.6%) hips, and joint-space narrowing in 4 (3.4%) hips. Based on the BASRI-hip scoring system, 68, 24, 18, 6 and 0 hips had no, suspicious, mild, moderate or severe damage on conventional radiographs of the pelvis, respectively. Thirty-five hips in 20 patients had current or past pain or limitation. The proportion of hip involvement according to MR imaging, radiographs, and clinical symptoms was 74.1% (86/116), 20.7% (24/116), and 30.2% (35/116), respectively. MR imaging yielded higher values than radiographs and clinical symptoms in the detection of hip involvement in patients with AS (χ² = 66.45 and 44.93, P <0.05). Interreader reliability for interpretation of findings was acceptable for both MRI and radiographs. During follow-up, radiological hip involvement were found in 10 hips with BASRI-hip scores ≤1 at baseline and clinical symptoms appeared in 15 sides of the original asymptomatic hip. On baseline MR imaging, inflammatory changes were seen in all hips which appeared symptoms and/or radiological involvement both at baseline and during follow-up.

Conclusion

The proportion of hip involvement is much higher than that suggested by radiographic changes and clinical symptoms. MR imaging is superior to conventional radiographs and clinical symptoms in the detection of hip involvement. Joint effusion and synovial enhancement caused by synovitis are the commonest hip findings on MR imaging in patients with AS.     

Subchondral insufficiency fracture of the femoral head and medial femoral condyle

This case report documents the clinical, radiographic, and histologic findings in a 69-year-old obese man, who had subchondral insufficiency fracture both in the femoral head and medial femoral condyle. On plain radiographs, both lesions underwent subchondral collapse. Magnetic resonance images of the left hip showed a bone marrow edema pattern with associated low-intensity band on T1-weighted images, which was convex to the articular surface. The histopathologic findings in the hip and knee were characterized by the presence of a subchondral fracture with associated callus and granulation tissue along both sides of a fracture line. There was no evidence of antecedent osteonecrosis. To our knowledge, this is the first case report to describe the multiple occurrence of collapsed subchondral insufficiency fracture. Received: 22 May 1999 Revision requested: 5 August 1999 Revision received: 13 September 1999 Accepted: 15 September 1999     

Intraosseous epidermal cyst of the distal phalanx of the thumb: radiographic and magnetic resonance imaging findings

We report conventional radiographic and magnetic resonance imaging (MRI) findings of an intraosseous epidermal cyst of the distal phalanx of the right thumb in a 39-year-old man. Conventional radiographs showed a sharply well-circumscribed osteolytic lesion of the distal phalanx with interruption of its tip. The osteolytic lesion itself showed low signal intensity on T1-weighted images and high signal intensity on T2-weighted images without contrast enhancement. However, the soft tissues surrounding the osteolytic lesion demonstrated contrast enhancement on MRI. The combined conventional radiographic and MRI findings suggested the diagnosis of intraosseous epidermal cyst rather than enchondroma, giant cell tumor, intraosseous glomus tumor, aneurysmal bone cyst, or simple bone cyst.     

Idiopathic osteonecrosis of the scaphoid (Preiser's disease)--MRI gives new insights into etiology and pathology

Objective

To describe the imaging signs of idiopathic osteonecrosis of the scaphoid (Preiser's disease) and to differentiate the findings from scaphoid nonunion.

Material and methods

10 patients (4 men, 6 women, mean age 36.9 years) with radial-sided wrist pain were identified to suffer from primary osteonecrosis of the scaphoid. Imaging methods included radiograms in all cases, CT imaging in 9 cases, and contrast-enhanced MRI in 7 cases. In CT and MRI, images were also acquired in the sagittal-oblique plane for depicting the scaphoids in the entire longitudinal extension. Follow-up examinations were performed in 5 patients, two of them underwent surgery with pedicled bone grafts.

Results

In all patients, both osteosclerosis and lesions of the bone marrow were most intensive at the proximal scaphoid pole. A three-layered architecture was found. The zone of osteonecrosis was located most proximally, followed by a zone of repair in the middle, and the zone of viable bone marrow in the distal part of the scaphoid. In contrast to scaphoid nonunion, pathological fractures were exclusively located within the zone of osteonecrosis in 8 cases. Applying morphologic criteria, three stages of Preiser's disease were discernible. The initial stage (proximal osteosclerosis, but unaltered shape of the scaphoid), the advanced stage (pathologic fractures, volume loss of the proximal pole), and the final stage (osteonecrosis of the entire scaphoid).

Conclusion

Pathoanatomy of Preiser's disease and the differentiation into three zones of bone marrow viability can be explained with the retrograde blood supply of the scaphoid. In its natural course, three different stages can be depicted with the initial stage seen only in MRI.     

MRI findings of treated bacterial septic arthritis

Introduction

The purpose of this study was to report the MRI findings that can be encountered in successfully treated bacterial septic arthritis.

Materials and methods

The study included 12 patients (8 male and 4 female; mean age 38?years, range 9–85) with 13 proven cases of bacterial septic arthritis. The joints involved were hip (n?=?3), knee (n?=?3), shoulder (n?=?2), sacroiliac (n?=?2), ankle (n?=?1), wrist (n?=?1), and elbow (n?=?1). MRI examinations following surgical debridement and at initiation of antibiotic therapy and after successful treatment were compared for changes in effusion, synovium, bone, and periarticular soft tissues. Imaging findings were correlated with microbiological and clinical findings.

Results

Joint effusions were present in all joints at baseline and regressed significantly at follow-up MRI (p?=?0.001). Abscesses were present in 5 cases (38?%), and their sizes decreased significantly at follow-up (p?=?0.001). Synovial enhancement and thickening were observed in all joints at both baseline and follow-up MRI. Myositis/cellulitis was present in 10 cases (77?%) at baseline and in 8 cases (62?%) at follow-up MRI. Bone marrow edema was present in 10 joints (77?%) at baseline and persisted in 8 joints (62?%). Bone erosions were found in 8 joints (62?%) and persisted at follow-up MRI in all cases.

Conclusion

The sizes of joint effusions and abscesses appear to be the factors with the most potential for monitoring therapy for septic arthritis, since both decreased significantly following successful treatment. Synovial thickening and enhancement, periarticular myositis/cellulitis, and bone marrow edema can persist even after resolution of the infection.