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Objective: The objective of our study was to prospectively compare the diagnostic performance of MR arthrography and conventional MRI with surgical correlation in the same patient for detecting labrum and articular cartilage defects., Subjects and Methods: Twenty-eight patients (mean age, 31.8 years) underwent MR arthrography, conventional MRI, and subsequent hip surgery, which served as the reference standard. Labrum and cartilage defects were evaluated at MRI by two independent readers. A McNemar test and kappa statistics were used for statistical analysis., Results: At surgery, 31 labral tears were identified. MR arthrography had an advantage over conventional MRI for detecting labral tears at the anterosuperior quadrant (sensitivity of MR arthrography, 81% and 69% for readers 1 and 2, respectively; sensitivity of conventional MRI, 50% for both readers); this difference in performance between MR arthrography and conventional MRI was statistically significant for reader 1 (p = 0.02) but not for reader 2 (p = 0.2). Interobserver agreement for labral tears was higher for MR arthrography (κ = 0.81) than for conventional MRI (κ = 0.63). Surgery showed 31 acetabular cartilage defects and nine femoral cartilage defects. MR arthrography had an advantage over conventional MRI for detecting acetabular cartilage defects (sensitivity of MR arthrography, 71% and 92% for readers 1 and 2, respectively; sensitivity of conventional MRI, 58% and 83%), whereas there was no advantage to using MR arthrography for detecting femoral cartilage defects with statistically significant difference for the acetabular cartilage or femoral cartilage. Interobserver agreement was slightly higher for MR arthrography (κ = 0.50) than for conventional MRI (κ = 0.40) for assessing the acetabular cartilage and was almost identical for the femoral cartilage (κ = 0.62 and 0.63, respectively)., Conclusion: MR arthrography was superior to conventional MRI for detecting labral tears and acetabular cartilage defects and showed a higher interobserver agreement. For femoral cartilage lesions, both modalities yielded comparable results.

Objective: The objective of our study was to perform a systematic review of the semiquantitative and qualitative radiologic criteria that are used for the diagnosis of lumbar spinal stenosis (LSS)., Materials and Methods: A four-step systematic literature search including the MEDLINE database was performed by an experienced librarian to reveal all semiquantitative or qualitative radiologic criteria used for the diagnosis of LSS. The precise definitions of all criteria, normal or abnormal values (if applicable), and intra- and interrater reliability were noted by two independent readers. Descriptive statistics were used., Results: A total of 14 semiquantitative or qualitative radiologic parameters were identified and distinguished according to relevant anatomic spaces into criteria for central canal stenosis, lateral (recess) stenosis, and foraminal stenosis. Great variability in terms of the exact definitions of the criteria was found. For 10 of the 14 criteria, the intra- and interrater reliability data were found with kappa values ranging from 0.01 to 1.0., Conclusion: Our systematic literature review identified 14 different semiquantitative or qualitative radiologic criteria that are used for the diagnosis of LSS; however, these criteria show remarkable variability in terms of their exact individual definitions and intra- and interrater reliability.

Objective: The purpose of this study was to compare abnormalities detected on conventional shoulder radiography with improvement in pain and shoulder function after subacromial injections., Subjects and Methods: We conducted a prospective outcomes study including 98 consecutive patients after fluoroscopy-guided subacromial injections who returned outcome questionnaires and who underwent routine shoulder radiography. Numeric pain rating scale (NRS) data were collected before and, along with patient global impression of change (PGIC) data, at 1 week and 1 month after injection. Outcome differences were assessed using the Student t test and Mann-Whitney U test. Logistic regression analysis was done, including radiographic variables compared with the outcome improvement. The odds ratios with 95% CIs were identified for the significant predictors., Results: A significant difference in overall improvement was found depending on the posterior acromial slope. Patients with a slope of more than 36° had significantly lower NRS and PGIC scores at 1 week and 1 month (p < 0.025) compared with those with a slope of 36° or less, with 86.4% of patients with a slope of more than 36° reporting significant improvement at 1 month. This was the only variable linked with improvement in the logistic regression analysis, with an odds ratio of 2.16 (95% CI, 1.11-4.22). Patients with calcific tendinitis had significantly lower NRS scores at both 1 week and 1 month (p = 0.03 and 0.05, respectively) and PGIC scores at 1 week (p = 0.05)., Conclusion: A posterior acromial slope of more than 36° and the presence of calcific tendinitis on conventional shoulder radiography are associated with better outcomes. Patients with a slope of more than 36° showed the best improvement.

Objective: A few studies have reported on short-term outcomes of patients receiving imaging-guided injections into the foot articulations, but none have compared patient responses depending on the anatomic site injected. This study includes a large sample size facilitating the investigation of postinjection pain reduction overall and by specific articulation., Materials and Methods: Three hundred forty-eight patients with imaging-guided diagnostic or therapeutic injections into the foot articulations, with complete preinjection and 20- to 30-minute postinjection numeric rating scale pain data were included. The proportions of patients reporting clinically relevant pain reduction (≥ 50%) were calculated overall and for specific subgroups. The risk ratio comparing patients with osteoarthritis to those without osteoarthritis was calculated. Analysis of variance was used to compare outcomes between subgroups of patients based on injection site. The unpaired Student t test was used to compare responses of men versus women, those with and without a diagnosis of osteoarthritis, and more experienced versus less experienced radiologists., Results: Sixty-four percent of patients (224/348) reported clinically relevant pain reduction. The average decrease overall was 56% (SD, 36). Injections into the Lisfranc articulation were significantly more effective (61% pain reduction, p = 0.007) compared with other sites, with 74% of patients obtaining clinically relevant pain relief. Patients with osteoarthritis reported more relief (62%) compared with those without (50%, p = 0.002). No difference in outcomes comparing musculoskeletal radiologists with residents or fellows in training was found., Conclusion: Nearly two thirds of patients receiving imaging-guided injections into the foot articulations reported clinically relevant pain reduction. Lisfranc joint injections and patients with a diagnosis of osteoarthritis responded better.

Objective: The objective of our study was to evaluate whether there is injury to the transverse ligament of the atlas in patients with acute whiplash., Materials and Methods: Ninety patients with an acute (< 48 hours) symptomatic whiplash-associated injury and 90 healthy age- and sex-matched asymptomatic control subjects (mean age of patients and control subjects, 36 years) were included. The maximal sagittal thickness of the transverse ligament was measured on midsagittal T1 volumetric interpolated breath-hold examination (VIBE) images and transverse reformatted VIBE images. The signal intensity of the transverse ligament was measured on transverse STIR images and on transverse reformatted T1 VIBE images before and after IV administration of gadoterate. Contrast between the transverse ligament and CSF and alterations of contrast after gadoterate injection were calculated., Results: Patients had a minimally thicker transverse ligament (posttraumatic swelling) than control subjects, and the difference in thickness was significant in men only (p = 0.03). In patients, a significant signal alteration of the transverse ligament (p = 0.03) was seen on STIR (posttraumatic edema) and native VIBE sequences. The contrast between the transverse ligament and the CSF on VIBE images was significantly (p = 0.005) lower in patients than in control subjects. With the application of a contrast agent, the contrast difference between the transverse ligament and CSF in patients and control subjects was less pronounced (p = 0.038). There was no abnormal uptake of contrast agent by the transverse ligament or CSF., Conclusion: The results of our study indicate possible involvement of the transverse ligament in whiplash injury. Although MRI may be helpful to study injury-related changes of anatomic structures in cohorts, it is not suited for individual diagnosis because the alterations are too small.

Objective: The purpose of this article is to identify the most rotation-stable hindfoot alignment measurement techniques on hindfoot alignment view and long axial view radiographs., Materials and Methods: Hindfoot alignment was quantified on hindfoot alignment view and long axial view radiographs of a phantom in different rotation positions. Rotation stability of measurements using the calcaneal axis, the medial and lateral calcaneal contour, and the apparent moment arm were graphically compared. Interreader agreement was quantified using intraclass correlation coefficient., Results: On hindfoot alignment view radiographs, measurements using the medial and lateral calcaneal contour were rotation stable (± 5°). Measurements using the calcaneal axis were not reliable and showed considerable divergence with phantom rotation. Measurements using the apparent moment arm manifested an almost linear relationship to phantom rotation. On long axial view radiographs, all measurements manifested an almost linear relationship to phantom rotation, whereas those using the calcaneal axis were the most rotation stable. Interreader agreement of all measurement techniques was perfect on both hindfoot alignment and long axial view radiographs (intraclass correlation coefficient, 0.8-0.98; p < 0.001). Interreader agreement was slightly better on long axial view radiographs., Conclusion: Hindfoot alignment measurements should be performed on hindfoot alignment view radiographs using the medial or lateral calcaneal contour or on long axial view radiographs using the calcaneal axis. Interreader agreement of hindfoot alignment measurements is slightly better on long axial view radiographs than on hindfoot alignment view radiographs.

Objective: The purpose of this study was to evaluate pain relief 20 to 30 minutes after diagnostic or therapeutic injections into the sternoclavicular joint and to compare patient outcomes based on the CT diagnosis., Materials and Methods: Informed consent was obtained from each patient. Ethics approval was not required. Fifty patients who had CT-guided injections of corticosteroid and local anesthetic into their sternoclavicular joints were included in the study. Preinjection and 20- to 30-minute postinjection visual analog scale data were recorded and compared with the imaging findings agreed by consensus. Kappa statistics were calculated for the reliability of imaging diagnosis. The percentage of patients improving after joint injection was calculated, and the risk ratio comparing the response of patients with osteoarthritis to those without osteoarthritis was completed. The correlation between the severity of each patient's osteoarthritis and the pain response was calculated using Spearman's correlation coefficient., Results: Sixty-six percent of the patients reported clinically significant pain reduction at between 20 and 30 minutes after injection. The proportion of patients with osteoarthritis who had a clinically significant response was 67% compared with 64% for patients who did not have osteoarthritis. This difference was not statistically or clinically significant. There was no correlation between the severity of osteoarthritis and the amount of pain reduction (r = 0.03). The reliability of imaging diagnosis was substantial., Conclusion: Two thirds of patients having sternoclavicular joint injections of corticosteroids and local anesthetics report clinically significant improvement regardless of the abnormalities detected on their CT images.

Objective: The purpose of our study was to evaluate the effectiveness of conventional radiography and CT for explaining the osseous causes of elbow stiffness., Materials and Methods: Two independent readers analyzed loose bodies and osteophytes on conventional radiography and CT (or CT arthrography) of the elbow in 94 consecutive patients (71 men, 23 women; mean age, 41 years; range, 18-68 years). Arthroscopic or surgical correlation was available in 58 (62%) patients. In all 94 patients, the expected restriction of motion was measured on images and correlated (Pearson's correlation) with the clinical restriction of motion. Kappa statistics were performed for interobserver agreement., Results: Accuracy for detecting loose bodies was 67% with conventional radiography and 79% with CT. Differences in accuracy were most pronounced for detecting loose bodies in the posterior joint space (64% for conventional radiography vs 79% for CT). Accuracy for detecting osteophytes was 69% with conventional radiography and 76% with CT. Expected restriction of motion on conventional radiography correlated significantly with clinical restriction for only one reader for flexion (R = 0.21, p = 0.04). Expected restriction of extension on CT correlated significantly with clinical restriction of motion by both readers (R = 0.34 and 0.33, p = 0.001 and 0.001, respectively). Expected restriction of flexion on CT correlated significantly by one reader (R = 0.24, p = 0.02). Interobserver agreement with regard to detection of both loose bodies and osteophytes was higher for CT (kappa = 0.83 and 0.76) than for conventional radiography (0.64 and 0.60)., Conclusion: CT is more effective than conventional radiography in explaining the osseous causes of elbow stiffness.

Objective: The objective of our study was to retrospectively evaluate the association between abnormalities of the lesser tuberosity and subscapularis tendon lesions., Materials and Methods: Cortical irregularities and cysts of the lesser tuberosity were evaluated on radiographs and MR images in 70 patients: 31 with normal subscapularis tendons and 39 with subscapularis tendon tears. These imaging findings were correlated with subscapularis tendon tears diagnosed during arthroscopy and with fatty atrophy of the subscapularis muscle seen on MR images. Correlations between imaging findings, patient age, history of trauma, and the reference standards were assessed using gamma coefficients. Interreader agreement was calculated using kappa values., Results: For the diagnosis of subscapularis tendon tears, the sensitivity of cortical irregularities and cysts on radiographs was 44%/51% (reader 1/reader 2) and 21%/21%, respectively; specificity was 65%/68% and 87%/87%. The sensitivity of cortical irregularities and cysts on MRI was 64%/72% and 36%/39%. Specificity was 48%/45% and 81%/77%. For fatty atrophy of the subscapularis muscle, the sensitivity of cortical irregularities and cysts on radiographs was 67%/73% and 17%/27%, respectively; the specificity was 63%/63% and 83%/85%. Significant (p < 0.05) positive correlations were found between cortical irregularities and surgical grade of subscapularis tendon tear for reader 2 (radiography, gamma = 0.39; MRI, gamma = 0.45) and between lesser tuberosity abnormalities and patient age (gamma = 0.11 and 0.43) for both readers. Interobserver agreement of imaging findings varied from moderate to substantial (kappa = 0.50-0.76)., Conclusion: Abnormalities of the lesser tuberosity are moderately associated with subscapularis tendon tears and patient age. Cysts seen in the lesser tuberosity on shoulder radiographs or MR images are relatively specific for subscapularis tendon tears and muscle atrophy.

Objective: The purpose of our study was to investigate the contrast dynamics and the relationship between visualization of intraarticular structures and time elapsed between intraarticular injection of contrast agent and MRI in symptomatic patients referred for MR arthrography of the shoulder, hip, and wrist., Subjects and Methods: Our local ethics committees and the national drug administration approved this multicentric study. We prospectively studied 11 shoulders, 11 hips, and 10 wrists. After the intraarticular gadolinium injection, patients underwent a baseline MR arthrography protocol (time point [TP] 1) and subsequent MRI at another four time points (TP 2-TP 5) up to 240 minutes. The course of contrast-to-noise ratio (CNR) over time was calculated. Three observers assessed the degree of visualization of different intraarticular structures and the overall image quality at each time point using a 3-point scale and a 5-point scale, respectively., Results: For all joints, CNR measurements showed peak CNR at TP 1 (21 minutes) and TP 2 (45 minutes) with a subsequent, near-logarithmic decline of CNR values over time. Visualization of different anatomic structures decreased over time. Overall image quality was insufficient for diagnostic purposes at TP 3 (96 minutes) in three (27%) of 11 shoulders and in three (27%) of 11 hips. In two (20%) of 10 wrists, image quality was insufficient at TP 2 (45 minutes)., Conclusion: For MR arthrography, the degree of visualization of intraarticular structures depends on the time elapsed between contrast injection and MRI. MR arthrography of the shoulder and hip should be performed within 90 minutes, and MR arthrography of the wrist should be performed within 45 minutes, after intraarticular injection.

Objective: The objective of our study was to investigate outcome predictors of short- and medium-term therapeutic efficacy of facet joint blocks., Materials and Methods: Forty-two patients with chronic lower back pain who were undergoing facet joint blocks at one (n = 29) or two (n = 13) levels were analyzed. All patients underwent MRI or CT of the lumbar spine within 5 months before the facet joint blocks. The facet joint blocks were performed under fluoroscopic guidance. A small amount (< 0.3 mL) of iodinated contrast agent, 0.5 mL of local anesthetics and 0.5 mL of steroids, were injected. The initial pain response was prospectively assessed using a visual analogue scale. Additional data, including short-term effect (> 1 week) and medium-term effect (> 3 months), were collected by a structured telephone interview. CT and MRI were reviewed with regard to the extent of facet joint abnormalities. Multiple logistic regression analyses were conducted to identify outcome predictor for efficacy of facet joint blocks., Results: A positive immediate effect was seen in 31 patients (74%). A positive medium-term effect was found in 14 patients (33%). Pain alleviated by motion (p = 0.035) and the absence of joint-blocking sensation (p = 0.042) predicted pain relief. However, the extent of facet joint osteoarthritis on MRI and CT was not a significant predictor for outcome (p = 0.57-0.95)., Conclusion: Facet joint blocks appear to have a beneficial medium-term effect in one third of patients with chronic lower back pain and may therefore be a reasonable adjunct to nonoperative treatment. However, outcome appears to depend on clinical, not on morphologic, imaging findings.

Objective: Our objective was to determine the diagnostic performance of CT-guided core biopsy including both intervertebral disks and subchondral bone in suspected spondylodiskitis and compare the results with those for other biopsy techniques., Conclusion: CT-guided core biopsy of subchondral bone and intervertebral space compares favorably to previously published studies because histology can provide the diagnosis even when no specific infectious agent is isolated.

Objective: The purpose of our study was to compare diagnostic performance, reviewer confidence, and time requirements in the MRI diagnosis of meniscal tears for three types of reviewers and two types of image documentations (PACS vs hard copies)., Materials and Methods: An experienced musculoskeletal radiologist (reviewer 1), a fellow in musculoskeletal radiology (reviewer 2), and a junior staff member in orthopedic surgery (reviewer 3) evaluated MR images displayed on PACS monitors and hard copies independently and in a blinded fashion with regard to the presence or absence of meniscal tears. Seventy-one patients (mean age, 45.4 years; range, 16-80 years) were consecutively included if they had undergone both MRI of the knee and arthroscopy within 4 months. Arthroscopy was the standard of reference. Evaluation time and the reviewer's confidence in his or her diagnosis (Visual Analogue Scale, possible values of 0-100) were determined., Results: Accuracies, sensitivities, and specificities in diagnosing meniscal tears were 80-87%, 63-85%, and 87-93% for soft copies and 82-85%, 64-76%, and 87-94.0%, respectively, for hard copies. Intrareviewer differences between PACS and hard copies were not significant for any of the three reviewers (McNemar tests). Reviewer 3 was less sensitive but more specific in the diagnosis of meniscal tears than reviewers 1 and 2. This difference was significant for both the PACS and hard copies. The reviewers' confidence in their diagnoses and evaluation times were not significantly different for PACS and hard copies (analysis of variance with Bonferroni post hoc analysis)., Conclusion: Differences in the diagnostic performance of suspected meniscal tears depend on reviewer experience rather than on the type of documentation.

Objective: The objective of this study was to investigate the diagnostic performance of MR arthrography after rotator cuff repair., Materials and Methods: MR arthrographic examinations of the shoulder performed after rotator cuff repair and before revision surgery were retrospectively analyzed in 48 patients (31 males, 17 females; mean age, 50.3 years; age range, 17-69 years). Full-thickness and partial-thickness defects of the supraspinatus, infraspinatus, and subscapularis tendons were diagnosed independently by two radiologists. Revision surgery served as the standard of reference., Results: Observer 1 correctly recognized five of eight intact supraspinatus tendons, 10 of 19 partial-thickness defects, and 19 of 21 full-thickness defects. For observer 2, the numbers were three of eight, eight of 19, and 18 of 21. The corresponding numbers for the infraspinatus tendon for observer 1 were 28 of 31, 0 of three, and 14 of 14 tendons. For observer 2, they were 28 of 31, two of three, and 11 of 14. For the subscapularis tendon, observer 1 made the correct diagnosis in 18 of 31, five of six, and nine of 11 tendons. The results for observer 2 were 26 of 31, one of six, and 10 of 11 tendons. Interobserver agreement (weighted kappa) was 0.47 for the supraspinatus, 0.64 for the infraspinatus, and 0.20 for the subscapularis tendons, respectively., Conclusion: Postoperative full-thickness defects of the rotator cuff are reliably diagnosed with MR arthrography. The diagnostic performance for partial-thickness defects is only moderate.

Objective: We sought to evaluate the diagnostic value of a 2D multiple-echo data image combination (MEDIC) MRI sequence in the detection of patellar cartilage defects., Materials and Methods: Our study included 52 consecutive patients who had knee surgery within 4 months of undergoing an MRI examination including an axial 2D MEDIC (TR/TE, 884/26; flip angle, 30 degrees ) sequence. Cartilage was surgically graded on a 5-point scale: 0, normal; 1, softening or swelling; 2, partial thickness defect; 3, fissuring to the level of the subchondral bone; or 4, exposed subchondral bone. Cartilage was graded on MRI according to a scale that was almost identical to the surgical scale except that grade 1 lesions were defined as signal alteration or swelling of cartilage. Two blinded reviewers independently analyzed patellar cartilage. Sensitivity, specificity, accuracy, and weighted kappa values for interobserver variability were calculated., Results: Low-grade cartilage lesions predominated in our study group. When grade 2 or higher was considered the threshold for relevance, the sensitivity, specificity, and accuracy for the MEDIC sequence was as high as 79%, 82%, and 81%, respectively. Increasing the threshold of relevance to grade 3 increased the sensitivity, specificity, and accuracy to as high as 83%, 91%, and 90%, respectively. Interobserver agreement for the MEDIC sequence was good (weighted kappa = 0.68)., Conclusion: The 2D MEDIC sequence performs comparably to previously described sequences optimized for cartilage imaging such as the 3D double-echo steady-state or 3D spoiled gradient-recalled sequences with good interobserver agreement, high sensitivity, and excellent specificity for revealing low- to intermediate-degree cartilage defects.

Objective: Our aim was to describe MRI and CT characteristics of primary lymphoma of bone during and after successful treatment., Conclusion: MRI showed a rapid decrease of tumor volume with complete disappearance of the soft-tissue component. Minor signal abnormalities of bone marrow without clinical relevance persisted for up to 2 years. CT showed bone remodeling within months with a persistent architecture similar to that of Paget's disease of the bone.

Objective: The objective of our study was to compare the diagnostic performance of a dedicated cartilage MR sequence (water-excitation 3D double-echo steady-state) with a standard MR sequence (T1-weighted spin-echo) in detecting articular cartilage lesions of the hip after intraarticular injection of gadopentetate dimeglumine., Materials and Methods: In 50 MR arthrograms of the hip joint obtained in 47 consecutive patients, a sagittal 3D double-echo steady-state sequence (TR/TE, 24/6.5; flip angle, 25 degrees ) was compared with a sagittal T1-weighted spin-echo sequence (350/14). Two musculoskeletal radiologists independently evaluated articular cartilage. Sensitivity and specificity for detecting cartilage defects were calculated for those hips that underwent open surgery (n = 21). Lesion conspicuity was retrospectively reviewed and graded between 1 (not visible) and 5 (well defined)., Results: At surgery, a total of 26 lesions of the acetabular (n = 20) and femoral (n = 6) cartilage were found. For the 3D double-echo steady-state and T1-weighted spin-echo sequences, sensitivities and specificities for cartilage lesion detection were 58% and 88% and 81% and 81% for reviewer 1 and 62% and 94% and 62% and 100% for reviewer 2, respectively. Lesion conspicuity was significantly superior (p = 0.036) for the 3D double-echo steady-state sequence (mean grade, 3.4) compared with the T1-weighted spin-echo sequence (mean grade, 3.0). The kappa value was fair for the 3D double-echo steady-state sequence (kappa = 0.40) and moderate for the T1-weighted spin-echo sequence (kappa = 0.55)., Conclusion: The 3D double-echo steady-state sequence optimized for cartilage imaging improves lesion conspicuity but does not improve diagnostic performance.

Objective: The objective of this study was to determine gray-scale and power Doppler sonographic findings in patients with arthrofibrosis associated with total knee arthroplasty. SUBJECTS AND METHODS. From a consecutive cohort of more than 3000 mobilebearing total knee arthroplasties, 44 cases (1.5%) with arthrofibrosis were identified, of which 38 were recruited for a clinical and sonographic investigation. A control group of 38 patients with a well-functioning total knee arthroplasty was matched. Synovial hypertrophy, presence of neovascularity, patellar tendon thickness, and extent of effusion were assessed., Results: Synovial membrane thickness was significantly (p < 0.001) increased in the arthrofibrosis group (medial, 3.4 mm; lateral, 3.0 mm; suprapatellar, 3.1 mm) when compared with the control group (medial, 2.0 mm; lateral, 2.0 mm; suprapatellar, 1.9 mm). When a cutoff of 3.0 mm was used, sonography had a sensitivity of 84% and a specificity of 82% for detecting arthrofibrosis. Neovascularity (rated as grades 0-3) of the synovial membrane and Hoffa's fat pad was significantly (p

Objective: Our objective was to evaluate the predictive value of various MRI findings in the acromioclavicular joint for pain relief after intraarticular injection., Materials and Methods: The acromioclavicular joint of 50 patients (20 women, 30 men; mean age, 51 years; range, 25-75 years) was evaluated on MRIs of the shoulder. Osteophytes, subchondral cysts and irregularities, bone marrow edema, joint effusion, and joint capsule hypertrophy were assessed by two musculoskeletal radiologists in consensus. Local anesthetics were injected into the acromioclavicular joint with fluoroscopic guidance. Patients graded pain relief on a visual analogue scale (0-100%) after 15 min. The relationship between pain relief and MRI findings was assessed with the Mann-Whitney U test. Pain relief equal to or greater than 70% was rated as a positive response to the injection. This cutoff value was used to calculate sensitivity, specificity, accuracy, and predictive values of the various MRI findings in determining which acromioclavicular joints were responsive to joint injections., Results: Mean pain relief after injection was 38%. Pain relief was significantly related to capsular hypertrophy (p = 0.007) and was equal to or greater than 70% in 11 patients. The sensitivity in diagnosing a successful injection (range, 9-82%) was highest for caudal osteophytes (82%) and capsular hypertrophy (73%). The specificity (range, 51-97%) was highest for subchondral cysts (97%), subchondral bone marrow edema (95%), and joint effusion (92%)., Conclusion: Pain relief after intraarticular injection is significantly related to capsular hypertrophy diagnosed on MRI. MRI findings have a reasonable sensitivity and a high specificity in predicting relevant short-term pain relief after intraarticular injection.

Objective: The purpose of this study was to evaluate the prevalence of MR abnormalities of the knee on the symptomatic and contralateral asymptomatic sides in patients with suspected meniscal tears. SUBJECTS AND METHODS. One hundred patients (mean age, 42.7 years; range, 18-73 years) referred for suspected meniscal tears were prospectively examined with MRI of both knees when the contralateral knee was asymptomatic. The prevalence of various types of meniscal tears and other MR abnormalities was determined., Results: Meniscal tears were found in 57 symptomatic knees and in 36 contralateral asymptomatic knees. In those 57 patients with a meniscal tear on the symptomatic side, the prevalence of asymptomatic tears in the contralateral side was 63% (36/57). Horizontal or oblique meniscal tears were found medially in 32 and laterally in 11 symptomatic knees, and medially in 29 and laterally in eight asymptomatic knees. Radial, vertical, complex, or displaced tears were found medially in 18 and laterally in five symptomatic knees, and medially in five and laterally in none of the asymptomatic knees. Collateral ligament abnormalities were found in 53 symptomatic knees and in six asymptomatic knees. Pericapsular soft-tissue abnormalities were found in 64 symptomatic and in 12 asymptomatic knees. Edema-like bone marrow abnormalities were found in 36 symptomatic and in three asymptomatic knees., Conclusion: Horizontal or oblique meniscal tears are frequently encountered in both asymptomatic and symptomatic knees and may not always be related to symptoms. However, radial, vertical, complex, or displaced meniscal tears and abnormalities of the collateral ligaments, pericapsular soft tissues, and bone marrow are found almost exclusively on the symptomatic side and appear to be clinically more meaningful.

Objective: The purposes of this study were to evaluate the prevalence and determine the size of meniscal cysts, ganglionic cysts, synovial cysts of the popliteal space, fluid-filled bursae, and other fluid collections on MR images of asymptomatic knees., Materials and Methods: MR images of 102 asymptomatic knees were evaluated with regard to the prevalence of meniscal cysts, ganglionic cysts, synovial cysts of the popliteal space, fluid-filled bursae, and other fluid collections. The MR examinations were performed in patients (mean age, 42.8 years; age range, 18-73 years) with clinically suspected meniscal lesions in the contralateral knee. The craniocaudal, anteroposterior, and mediolateral diameters of detectable abnormal fluid collections were measured., Results: Medial meniscal cysts (mean size [craniocaudal x anteroposterior x mediolateral], 9 x 6 x 13 mm) were found in four asymptomatic knees. Neither lateral meniscal cysts nor ganglionic cysts of the cruciate ligaments were identified. Twenty-six synovial cysts of the popliteal space (Baker's cyst)-consisting of 11 gastrocnemius portions (mean size, 19 x 8 x 10 mm) and 15 semimembranosus portions (mean size, 20 x 7 x 9 mm)-were found in 19 knees. Twenty-four (92%) of these cysts had a maximal diameter of 30 mm or less. Fluid-filled bursae were found in 49 knees. The deep infrapatellar bursa was most commonly involved (42 knees; mean size, 6 x 3 x 5 mm). Fluid-filled anserine bursae (mean size, 27 x 12 x 10 mm) were detected in five knees., Conclusion: Meniscal cysts may be present in asymptomatic knees, at least on the medial side. Synovial cysts of the popliteal space can be found in approximately one fifth of asymptomatic knees. Their maximal diameter is usually smaller than 30 mm.

Objective: The objective of our study was to evaluate the usefulness of FDG positron emission tomography (PET) for the differentiation of degenerative and infectious endplate abnormalities in the lumbar spine that were detected on MR imaging., Subjects and Methods: FDG PET was performed prospectively in 30 consecutive patients with substantial endplate abnormalities (craniocaudal diameter of bone marrow abnormalities, > or = 25% of vertebral height) found during MR imaging of the lumbar spine. Both the MR and PET images were evaluated by two experienced musculoskeletal radiologists and two experienced nuclear physicians. The diagnosis of either degeneration with different types of endplate abnormalities or disk-space infection was determined. Clinical follow-up and, in selected cases, bone biopsies with cultures were used as the standard of reference., Results: On the MR images, 25 of the 38 degenerated levels were classified as Modic type I, 13 levels as type II, and none as type III. Five disk-space infections were diagnosed in four patients. MR imaging findings were false-positive at one disk level with type I abnormalities and false-negative at two levels with infection. PET did not show FDG uptake in the intervertebral spaces of any patient with degenerative disease. FDG PET findings were true-positive in all five levels with disk-space infection. The sensitivity and specificity for MR imaging in detecting disk-space infection were 50% and 96%, and were 100% and 100% for FDG PET, respectively (not significant, McNemar test, p = 0.5)., Conclusion: Our findings suggest that FDG PET may prove useful for differentiation of degenerative and infectious endplate abnormalities detected on MR imaging. Even in active (Modic type I) degenerative endplate abnormalities in our series, PET did not show increased FDG uptake.