Pitfalls in MR morphology of the sterno-costo-clavicular region using whole-body MRI.

AIM: To analyse the imaging findings at the sterno-costo-clavicular (SCC) joint region using whole-body (WB) magnetic resonance imaging (MRI) in healthy individuals to minimize misinterpretation as changes due to spondyloarthritis (SpA). MATERIALS AND METHODS: As part of a cross-sectional study of 122 SpA patients, 75 healthy individuals (42/33 males/females; median age 30.3 years; range 17.7-63.8 years) were scanned using sagittal and coronal WB short tau inversion recovery (STIR) and T1-weighted MRI sequences. The SCC region was analysed independently by seven readers for bone marrow oedema (BMO), erosions, subchondral fat signal intensity (FSI), and joint fluid accumulation. RESULTS: SCC changes simulating inflammation were reported by four or more of the seven readers in 15 (20%) healthy individuals (12 male/three female; median age 32.1 years; range 20.2-48 years). Thirteen individuals (17%) had changes at the manubriosternal joint (MSJ); five had BMO, one BMO + erosion, four erosion, two erosion + FSI, and one FSI only. Changes at the sternoclavicular joint occurred in three individuals (4%) encompassing erosion, erosion + FSI + BMO, and joint fluid accumulation, respectively. One patient had both MSJ and sternoclavicular joint changes. CONCLUSIONS: Findings mimicking inflammatory changes occurred in healthy individuals, particularly in the MSJ. Awareness of this is important in recognition of SCC inflammation in SpA.

MR/CT image fusion of the spine after spondylodesis: a feasibility study.

The objective of this study is to evaluate feasibility, accuracy and time requirements of MR/CT image fusion of the lumbar spine after spondylodesis. Sagittal MR and CT images derived from standard imaging protocols (sagittal T2-weighted MR/sagittal reformatted multi-planar-reformation of the CT) of the lumbar spine with correct (n = 5) and incorrect (n = 5) implant position were fused by two readers (R1, R2) using OsiriX in two sessions placing one (session 1) or two (session 2) reference point(s) on the dorsal tip(s) of the cranial and caudal endplates from the second lumbar to the first sacral vertebra. R1 was an experienced musculoskeletal radiologist; R2 a spine surgeon, both had received a short training on the software tool. Fusion times and fusion accuracy, defined as the largest deviation between MR and CT in the median sagittal plane on the ventral tip of the cranial end plate of the most cranial vertebra visible on the CT, were measured in both sessions. Correct or incorrect implant position was evaluated upon the fused images for all patients by an experienced senior staff musculoskeletal radiologist. Mean fusion time (session 1/session 2; in seconds) was 100.4/95 (R1) and 104.2/119.8 (R2). Mean fusion deviation (session 1/session 2; in mm) was 1.24/2.20 (R1) and 0.79/1.62 (R2). The correct/incorrect implant position was identified correctly in all cases. In conclusion, MR/CT image fusion of the spine with metallic implants is feasible, fast, accurate and easy to implement in daily routine work.

Spatial variation in T1 of healthy human articular cartilage of the knee joint.

The longitudinal relaxation time T(1) of native cartilage is frequently assumed to be constant. To redress this, the spatial variation of T(1) in unenhanced healthy human knee cartilage in different compartments and cartilage layers was investigated. Knees of 25 volunteers were examined on a 1.5 T MRI system. A three-dimensional gradient-echo sequence with a variable flip angle, in combination with parallel imaging, was used for rapid T(1) mapping of the whole knee. Regions of interest (ROIs) were defined in five different cartilage segments (medial and lateral femoral cartilage, medial and lateral tibial cartilage and patellar cartilage). Pooled histograms and averaged profiles across the cartilage thickness were generated. The mean values were compared for global variance using the Kruskal-Wallis test and pairwise using the Mann-Whitney U-test. Mean T(1) decreased from 900-1100 ms in superficial cartilage to 400-500 ms in deep cartilage. The averaged T(1) value of the medial femoral cartilage was 702+/-68 ms, of the lateral femoral cartilage 630+/-75 ms, of the medial tibial cartilage 700+/-87 ms, of the lateral tibial cartilage 594+/-74 ms and of the patellar cartilage 666+/-78 ms. There were significant differences between the medial and lateral compartment (p<0.01). In each cartilage segment, T(1) decreased considerably from superficial to deep cartilage. Only small variations of T(1) between different cartilage segments were found but with a significant difference between the medial and lateral compartments.

Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) of cadaveric shoulders: comparison of contrast dynamics in hyaline and fibrous cartilage after intraarticular gadolinium injection.

BACKGROUND: Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a novel method to investigate cartilaginous and fibrocartilaginous structures. PURPOSE: To investigate the contrast dynamics in hyaline and fibrous cartilage of the glenohumeral joint after intraarticular injection of gadopentetate dimeglumine. MATERIAL AND METHODS: Transverse T(1) maps were acquired on a 1.5T scanner before and after intraarticular injection of 2.0 mmol/l gadopentetate dimeglumine in five cadaveric shoulders using a dual flip angle three-dimensional gradient echo (3D-GRE) sequence. The acquisition time for the T(1) maps was 5 min 5 s for the whole shoulder. Measurements were repeated every 15 min over 2.5 hours. Regions of interest (ROIs) covering the glenoid cartilage and the labrum were drawn to assess the temporal evolution of the relaxation parameters. RESULTS: T(1) of unenhanced hyaline cartilage of the glenoid was 568+/-34 ms. T(1) of unenhanced fibrous cartilage of the labrum was 552+/-38 ms. Significant differences (P=0.002 and 0.03) in the relaxation parameters were already measurable after 15 min. After 2 to 2.5 hours, hyaline and fibrous cartilage still demonstrated decreasing relaxation parameters, with a larger range of the T(1)(Gd) values in fibrous cartilage. T(1) and triangle Delta R(1) values of hyaline and fibrous cartilage after 2.5 hours were 351+/-16 ms and 1.1+/-0.09 s(-1), and 332+/-31 ms and 1.2+/-0.1 s(-1), respectively. CONCLUSION: A significant decrease in T(1)(Gd) was found 15 min after intraarticular contrast injection. Contrast accumulation was faster in hyaline than in fibrous cartilage. After 2.5 hours, contrast accumulation showed a higher rate of decrease in hyaline cartilage, but neither hyaline nor fibrous cartilage had reached equilibrium.

Unsuspected osteomyelitis is frequent in persistent diabetic foot ulcer and better diagnosed by MRI than by 18F-FDG PET or 99mTc-MOAB.

AIM: Prevalence, optimal diagnostic approach and consequences of clinically unsuspected osteomyelitis in diabetic foot ulcers are unclear. Early diagnosis of this infection may be crucial to ensure correct management. METHODS: We conducted a prospective study in 20 diabetic patients with a chronic foot ulcer (>8 weeks) without antibiotic pretreatment and without clinical signs for osteomyelitis to assess the prevalence of clinically unsuspected osteomyelitis and to compare the value of magnetic resonance imaging (MRI), 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) and 99mTc-labelled monoclonal antigranulocyte antibody scintigraphy (99mTc-MOAB). Those with suggestive scans underwent bone biopsy for histology (n = 7). RESULTS: Osteomyelitis was confirmed by biopsy in seven of the 20 clinically unsuspected foot ulcers. Presence of osteomyelitis was not related to age, ulcer size, ulcer duration, duration of diabetes or HbA1c. C-reactive protein was slightly elevated in patients with osteomyelitis (35.1 +/- 16.0 mg L(-1) vs. 12.2 +/- 2.6 mg L(-1) in patients with and without osteomyelitis respectively; P = 0.07). MRI was positive in six of the seven patients with proven osteomyelitis, whereas 18F-FDG PET and 99mTc-MOAB were positive only in (the same) two patients. Of the seven patients with osteomyelitis, five had lower limb amputation and in one patient the ulcer was persisting after 24 months of follow-up. In contrast, of the 13 patients without detectable signs of osteomyelitis on imaging modalities only two had lower limb amputation and two persisting ulcers. CONCLUSIONS: Clinically unsuspected osteomyelitis is frequent in persisting foot ulcers and is a high risk factor for adverse outcome. MRI appears superior to 18F-FDG PET and 99mTc-MOAB in detecting foot ulcer-associated osteomyelitis and might be the preferred imaging modality in patients with nonhealing diabetic foot ulcers.

Femoral component rotation and arthrofibrosis following mobile-bearing total knee arthroplasty.

The purpose of this study was to evaluate the femoral component rotation in a small subset of patients who had developed arthrofibrosis after mobile-bearing total knee arthroplasty (TKA). Arthrofibrosis was defined as flexion less than 90 degrees or a flexion contracture greater than 10 degrees following TKA. From a consecutive cohort of 3,058 mobile-bearing TKAs, 49 (1.6%) patients were diagnosed as having arthrofibrosis, of which 38 (86%) could be recruited for clinical assessment. Femoral rotation of a control group of 38 asymptomatic TKA patients matched for age, gender, and body mass index was also evaluated. The surgical epicondylar axis was compared with the posterior condylar axis for the femoral prosthesis. Femoral components in the arthrofibrosis group were significantly internally rotated by a mean of 4.7 degrees (SD 2.2 degrees , range 10 degrees internal to 1 degrees external). In the control group, the femoral component had a mean 0.3 degrees internal rotation (SD 2.3 degrees , range 4 degrees internal to 6 degrees external). Following mobile-bearing TKA, there is a significant correlation between internal femoral component rotation and chronic arthrofibrosis.

Late solitary bone metastasis of a primary pulmonary synovial sarcoma with SYT-SSX1 translocation type: case report with a long follow-up.

Primary synovial sarcoma outside its classical presentation in para-articular soft tissue of young patients is rare but regularly reported. One of the rarest primary locations is the lung. We describe a 73-year-old female patient who presented with a solitary malignant bone tumor 8 years after the resection of a lung neoplasm. The bone tumor was classified as an osteosarcoma and the lung tumor as an atypical carcinoid tumor at their first respective diagnostic work-ups. The resection of the affected humerus with allograft and endoprosthesis implantation followed. Reevaluation of the tumor samples at the time of the local recurrence of the bone tumor 6 years following the initial symptoms of the bone tumor lead to the reclassification of both specimens as synovial sarcomas. Both neoplasms contained the SYT-SSX1 type of the diagnostic translocation t(X;18) as detected by the reverse-transcription polymerase chain reaction analysis. The patient died 14 years after the resection of the primary synovial sarcoma of the lung and 6 years following the occurrence of the bone metastasis. This prolonged clinical course is uncommon for the SYT-SSX1 translocation, which, in other locations, is usually associated with an unfavorable prognosis.

Surgical treatment of cervical myelopathy of unclear aetiology.

In some cases neither the clinical pattern nor the findings of magnetic resonance imaging (MRI) can help to determine the cause of a cervical myelopathy. The differential diagnosis of such cases as a rule includes spondylotic myelopathy, a solitary focus of multiple sclerosis and an intramedullary tumour in early stage. Worsening of signs and symptoms due to the circumscribed lesion of the spinal cord can require surgical treatment, even if no certain diagnosis could be stated thus far. The question is how to choose a surgical procedure which is beneficial for all three kinds of spinal cord pathology in their initial stage, which at the same time does not jeopardise spine and spinal cord and allows secondary surgery if needed after the precise nature of the lesion has been assessed. Ventral decompression and fusion with or without dorsal decompression seems to be a convincing procedure.

Osteonecrosis diagnosed on MR images of the knee. Relationship to reduced bone mineral density determined by high resolution peripheral quantitative CT.

PURPOSE: To evaluate if osteonecrosis diagnosed on MR images of the knee relates to reduced bone mineral density (BMD) and may be caused by an insufficiency fracture. MATERIAL AND METHODS: Thirty-two consecutive patients (8 men, 24 women; age range 27-82 years, mean 62 years) with MR findings of osteonecrosis of the femoral or tibial condyle were prospectively included. Trabecular and cortical BMD were measured with high resolution peripheral quantitative CT in the non-dominant distal radius and the tibia of the involved extremity. One tibia was not measured due to posttraumatic deformity. RESULTS: The mean trabecular BMD of the radius was 81% of the young-adult average peak BMD (range 19-160%). The mean cortical BMD in the radius was 86% (range 63-108%). The mean trabecular BMD in the tibia was 92% (range 28-160%). The mean cortical BMD in the tibia was 86% (range 49-132%). The values of the trabecular bone of the distal radius (tibia) were normal in 11 (15) patients, osteopenic in 12 (4), and osteoporotic in 9 (12), respectively. The cortical bone values of the distal radius (tibia) were normal in 12 (13) patients, osteopenic in 12 (12), and osteoporotic in 8 (6), respectively. CONCLUSION: Osteoporosis and osteopenia are commonly found in patients with osteonecrosis of the knee as diagnosed on MR images. This indicates that for some patients an insufficiency mechanism may be responsible for the MR findings. However, in the patients with normal bone density other reasons for osteonecrosis may be present.

Cartilage lesions in the ankle joint: comparison of MR arthrography and CT arthrography.

OBJECTIVE: To compare MR arthrography and CT arthrography for the evaluation of cartilage lesions in the ankle joint. DESIGN AND PATIENTS: Thirty-six consecutive patients with clinically suspected cartilage lesions were prospectively included in the study. A 1:1 mixture of diluted gadoteridol (4 mmol/l) and iopamidol (300 mg iodine/ml) was injected. The articular cartilages of the talus, tibia, and fibula were analyzed separately by two musculoskeletal radiologists. A review panel consisting of two musculoskeletal radiologists and an orthopedic surgeon represented the standard of reference. RESULTS: For reader 1 accuracy of MR arthrography in the talus/tibia/fibula (88%/88%/94%) was slightly inferior to CT arthrography (90%/94%/92%). For reader 2, the accuracy was 76%/78%/83% for MR arthrography, and 92%/93%/92% for CT arthrography, respectively. Interobserver agreement for MR arthrography was 79%/74%/89% (kappa 0.47/0.34/0.27), while interobserver agreement for CT arthrography was 89%/90%/89% (kappa 0.69/0.54/0.54). CONCLUSION: CT arthrography appears to be more reliable than MR arthrography for the detection of cartilage lesions in the ankle joint.

Gorham-Stout disease of the shoulder girdle and cervico-thoracic spine: fatal course in a 65-year-old woman.

A case of Gorham-Stout disease of the shoulder girdle and cervico-thoracic spine in a 65-year-old woman is described. The patient presented with progressive neurologic symptoms, pain, and deformities of the cervico-thoracic spine as well as of her left shoulder following a traumatic shoulder luxation. Since the patient had a history of uterine carcinoma, the current disease was clinically difficult to differentiate from osteolytic metastases. The results of the clinical, radiological and histopathologic examination leading to the diagnosis of Gorham-Stout disease are described. Neither attempted surgery nor radiotherapy produced clinical improvement and the patient died 1 year after the first clinical evaluation.

The contour of the femoral head-neck junction as a predictor for the risk of anterior impingement.

Impingement by prominence at the femoral head-neck junction on the anterior acetabular rim may cause early osteoarthritis. Our aim was to develop a simple method to describe concavity at this junction, and then to test it by its ability to distinguish quantitatively a group of patients with clinical evidence of impingement from asymptomatic individuals who had normal hips on examination. MR scans of 39 patients with groin pain, decreased internal rotation and a positive impingement test were compared with those of 35 asymptomatic control subjects. The waist of the femoral head-neck junction was identified on tilted axial MR scans passing through the centre of the head. The anterior margin of the waist of the femoral neck was defined and measured by an angle (alpha). In addition, the width of the femoral head-neck junction was measured at two sites. Repeated measurements showed good reproducibility among four observers. The angle alpha averaged 74.0 degrees for the patients and 42.0 degrees for the control group (p < 0.001). Significant differences were also found between the patient and control groups for the scaled width of the femoral neck at both sites. Using standardised MRI, the symptomatic hips of patients who have impingement have significantly less concavity at the femoral head-neck junction than do normal hips. This test may be of value in patients with loss of internal rotation for which a cause is not found.

[Percutaneous transpedicular vertebroplasty for treatment of osteoporosis-induced vertebral fractures]. / Die perkutane transpedikuläre Vertebroplastik zur Behandlung Osteoporose bedingter Wirbelfrakturen.

Osteoporosis plays an increasing medical, social, and economic role in our society. Vertebral body fractures are the most common fractures, along with fractures around the hip joint, and fractures of the distal radius due to osteoporosis. An osteoporotic vertebral compression fracture can lead to incapacitating back pain and immobility and often requires in-hospital treatment. Vertebroplasty is an effective procedure consisting of the percutaneous injection of polymethylmethacrylate (PMMA) cement into vertebral bodies. Preliminary studies showed promising clinical results with this new technique. As there is a high incidence of cement leakage during the injection of the cement, we prefer to perform the procedure under computed tomography control with a fluoro-CT-option. Furthermore, we recommend that the procedure is only done in collaboration with a spine surgeon. In case of a neurological complication, immediate decompression of the spinal canal is mandatory. Vertebroplasty is a very promising, effective and safe method for the treatment for osteoporotic vertebral compression fractures. Based on our preliminary results, this method can be recommended for a more widespread clinical use.

Selective nerve root blocks for the treatment of sciatica: evaluation of injection site and effectiveness--a study with patients and cadavers.

PURPOSE: To relate different types of radiographic contrast material distributions to anatomic compartments by using cadaveric specimens and to relate the injection site to treatment-induced discomfort and therapeutic effect. MATERIALS AND METHODS: The contrast material distributions of selective nerve root blocks (SNRBs) in 36 patients (13 women, 23 men; mean age, 52 years; age range, 22-88 years) were graded by two radiologists in conference as type 1 (tubular appearance), type 2 (nerve root visible as filling defect), or type 3 (nerve root not visible). These patterns were correlated with pain reduction after 15 minutes and 2 weeks (with a visual analogue scale of 100-mm length). In addition, 30 nerve roots were injected with iodine-containing contrast material and blue dye in three cadaveric specimens. Radiographs were compared with anatomic sections. RESULTS: After 15 minutes and 2 weeks, 75% and 86% of the patients, respectively, reported pain relief. Mean pain relief length after 15 minutes for type 1 distribution was 60 mm; for type 2, 44 mm; and for type 3, 22 mm; and after 2 weeks, it was 34 mm for type 1, 31 mm for type 2, and 57 mm for type 3. There was no correlation between early and late response. Pain during intervention was less pronounced in type 2 injection, compared with type 1 (P = .002). On the basis of anatomic sections, type 1 injection was intraepineural; type 2, extraepineural; and type 3, paraneural. CONCLUSION: Therapeutic SNRB is effective in sciatica, but early response does not predict the effect after 2 weeks. Type 1 injections are more painful than type 2 injections.

Patient's assessment of discomfort during MR arthrography of the shoulder.

PURPOSE: To assess patient discomfort during (a) intraarticular contrast material injection (arthrography) and (b) magnetic resonance (MR) imaging in patients referred for MR arthrography of the shoulder and to compare the relative discomfort associated with each part of the examination. MATERIALS AND METHODS: With use of a visual analogue scale (VAS) and relative ratings, 202 consecutive patients referred for MR arthrography of the shoulder rated the expected discomfort and that actually experienced during both arthrography and MR imaging. The Student t test was used for statistical analysis. RESULTS: The average VAS score (0 = "did not feel anything," 100 = "unbearable") was 16.1 +/- 16.4 (SD) for arthrography and 20.2 +/- 25.0 for MR imaging. This difference was statistically significant (P =.036, paired t test). The discomfort experienced during arthrography was as expected in 90 (44.6%) patients, less than expected in 110 (54.4%), and worse than expected in two (1.0%). MR imaging-related discomfort was as expected in 114 (56.4%) patients, less than expected in 66 (32.7%), and worse in 22 (10.9%). Arthrography was rated worse than MR imaging by 53 (26.2%) patients, equal to MR imaging by 69 (34.2%), and less uncomfortable than MR imaging by 80 (39.6%). CONCLUSION: Arthrography-related discomfort was well tolerated, often less severe than anticipated, and rated less severe than MR imaging-related discomfort.

Magnetic resonance classification of lumbar intervertebral disc degeneration.

STUDY DESIGN: A reliability study was conducted. OBJECTIVES: To develop a classification system for lumbar disc degeneration based on routine magnetic resonance imaging, to investigate the applicability of a simple algorithm, and to assess the reliability of this classification system. SUMMARY OF BACKGROUND DATA: A standardized nomenclature in the assessment of disc abnormalities is a prerequisite for a comparison of data from different investigations. The reliability of the assessment has a crucial influence on the validity of the data. Grading systems of disc degeneration based on state of the art magnetic resonance imaging and corresponding reproducibility studies currently are sparse. METHODS: A grading system for lumbar disc degeneration was developed on the basis of the literature. An algorithm to assess the grading was developed and optimized by reviewing lumbar magnetic resonance examinations. The reliability of the algorithm in depicting intervertebral disc alterations was tested on the magnetic resonance images of 300 lumbar intervertebral discs in 60 patients (33 men and 27 women) with a mean age of 40 years (range, 10-83 years). All scans were analyzed independently by three observers. Intra- and interobserver reliabilities were assessed by calculating kappa statistics. RESULTS: There were 14 Grade I, 82 Grade II, 72 Grade III, 68 Grade IV, and 64 Grade V discs. The kappa coefficients for intra- and interobserver agreement were substantial to excellent: intraobserver (kappa range, 0.84-0.90) and interobserver (kappa range, 0.69-0.81). Complete agreement was obtained, on the average, in 83.8% of all the discs. A difference of one grade occurred in 15.9% and a difference of two or more grades in 1.3% of all the cases. CONCLUSION: Disc degeneration can be graded reliably on routine T2-weighted magnetic resonance images using the grading system and algorithm presented in this investigation.

Palmar tilt of the distal radius: influence of off-lateral projection initial observations.

PURPOSE: To evaluate the effect of slight off-lateral positioning of the wrist on measurements of the palmar tilt of the distal radius on lateral views and to determine how this effect can be corrected quantitatively. MATERIALS AND METHODS: Seven cadaveric forearms in neutral and various oblique positions (5 degrees, 10 degrees, 15 degrees, 20 degrees ) of supination and pronation were examined with lateral radiography. The palmar tilt of the distal radius measured on the radiographs was correlated with each position of the wrist and the distance between the position of the palmar cortex of the pisiform bone (P) and a reference point (point 0), which was defined as the midpoint within the interval between palmar cortices of the distal scaphoid pole and of the capitate head (P0 distance). The same measurements were performed on 11 wrists during arthrography. RESULTS: The apparent palmar tilt of the distal radius increased with supination of the forearm. Regression analysis with the P0 distance as independent and palmar tilt as dependent variables resulted in a slope of 0.95 in the seven cadaveric wrists and of 0.92 in the 11 wrist arthrograms. The squares of the correlation coefficients (R(2)) were 0.89 in cadaveric wrists and 0.69 in 11 wrist arthrograms. CONCLUSION: Differences in the palmar tilt produced by off-lateral projections of the wrist can be estimated from the measured difference of the P0 distance. A 1-mm difference in the P0 distance corresponds to a difference in the palmar tilt of approximately 1 degrees.

MR arthrography of the glenohumeral joint: two concentrations of gadoteridol versus Ringer solution as the intraarticular contrast material.

PURPOSE: To compare two concentrations of gadoteridol with Ringer solution as the contrast material for magnetic resonance (MR) arthrography of the glenohumeral joint. MATERIALS AND METHODS: One hundred fifty-six consecutive MR arthrograms were randomly obtained with either 2 mmol/L gadoteridol (n = 52), 4 mmol/L gadoteridol (n = 52), or Ringer solution (n = 52). MR arthrograms were assessed quantitatively (for contrast-to-noise ratio [CNR]) and qualitatively (for overall image quality, image contrast, degree of joint distention, and motion artifacts). MR diagnoses were compared with arthroscopic or surgical reports in 88 patients. RESULTS: The mean CNR at imaging was 40.4 with 2 mmol/L gadoteridol, 45.6 with 4 mmol/L gadoteridol, and 48.7 with Ringer solution. The CNR with 2 mmol/L gadoteridol was significantly lower than that with 4 mmol/L gadoteridol (P =.025) and Ringer solution (P =.012). Qualitative differences between the two gadoteridol concentrations were not significant. Ringer solution was significantly worse with regard to overall quality, motion artifacts, image contrast, and joint distention compared with both gadoteridol concentrations. Ringer solution was slightly more sensitive and less specific than the gadoteridol solutions in the detection of supraspinatus tears and less sensitive and more specific in enabling diagnosis of superior labrum anteroposterior lesions. CONCLUSION: MR arthrograms of the shoulder obtained with gadoteridol and those obtained with Ringer solution provided equivalent diagnostic accuracy. The authors, however, preferred the image quality of the gadoteridol-enhanced arthrograms.

MR arthrographic variability of the arthroscopically normal glenoid labrum: qualitative and quantitative assessment.

The purpose of this study was to assess qualitatively and quantitatively the MR arthrographic variability of the arthroscopically normal glenoid labrum. Form and signal abnormalities of arthroscopically normal labral parts were analyzed on axial and coronal MR arthrograms of 55 consecutive patients (mean age 43.8 years, age range 21-76 years) referred mainly for suspected rotator cuff lesions. Length and width of the labrum were measured. One hundred twenty-one of 241 (50%) arthroscopically normal labral parts demonstrated normal (low) signal intensity and normal form on MR arthrograms. Increased linear or globular signal intensity was present in 74 of 241 (31%) normal labral parts, deformed or fragmented labra in 28 (12%), complete separation of the labrum from the glenoid in 4 (2%), a cleft in 5 (2%), attenuation in 4 (2%), and complete absence in 5 (2%), respectively. The mean size of the normal labrum varied between 3.8 x 3.3 mm at the subscapularis bursa level (anteriorly) and 6.1 x 5.6 mm at the inferior portion of the glenoid (anteriorly). The size was not significantly different between arthroscopically normal and abnormal labral parts (p = 0.13-0.83). Since the MR appearance of the arthroscopically normal glenoid labrum varies considerably concerning signal intensity, form, and size, only major tears or detachments of the labrum should be diagnosed.