CT arthrography of adhesive capsulitis of the shoulder: Are MR signs applicable?

To determine if diagnostic signs of adhesive capsulitis (AC) of the shoulder at Magnetic Resonance Imaging (MRI) and arthrography (MRA) are applicable to CT arthrography (CTA). 22 shoulder CTAs with AC were retrospectively reviewed for features described in MR literature. The control group was composed of 83 shoulder CTA divided into four subgroups 1) normal (N = 20), 2) omarthrosis (N = 19), 3) labral injury (N = 23), and 4) rotator cuff tear (N = 21). Two musculoskeletal radiologists assessed the rotator interval (RI) for obliteration, increased width and thickening of coracohumeral ligament (CHL). The width and capsule thickness of the axillary recess were measured. The width of the axillary recess was significantly decreased in the AC group (4.6 ± 2.6 mm versus 9.9 ± 4.6 mm, p ≤ 0.0001; sensitivity and specificity of 84% and 80%). Thickness of the medial and lateral walls of the axillary capsule was significantly increased in the AC group (5.9 ± 1.3 mm versus 3.7 ± 1.1 mm, p ≤ 0.0001 and 5.7 ± 1 mm versus 3.5 ± 1.3 mm, p ≤ 0.0001, respectively). CHL thickness was significantly increased in the AC group (4.1 ± 1 mm (p ≤ 0.001)) in comparison to others groups. Obliteration of the RI was statistically significantly more frequent in patients with AC (72.7% (16/22) vs. 12% (10/83), p < 0.0001). Width of the RI did not differ significantly between patients and controls (p ≥ 0.428). Decreased axillary width, and thickened axillary capsule are MR signs of AC applicable to CTA. Evaluation of rotator interval seems useful and reproducible only for obliteration

Conventional Radiography of the Hip Revisited: Correlation with Advanced Imaging.

This review proposes a structured approach to analyzing conventional radiographs of adult hips by focusing on alterations of radiological bone density, femoral head contours, and the joint space. Conventional radiography enables detecting subtle changes in cortical contours and joint space width due to its high spatial resolution. It is limited to the detection of cortical changes in areas to which the x-ray beam is tangent. It has reduced sensitivity for the detection of trabecular bone and medullary changes. Radiographic findings in common hip disorders, such as osteoarthritis, osteonecrosis, transient osteoporosis, and subchondral insufficiency fractures, are correlated to changes on MR imaging and computed tomography

Magnetic Resonance Imaging of Accelerated Bone Remodeling.

A regional acceleration of bone remodeling may possibly follow biomechanical insults to the bone. This review assesses the literature and clinical arguments supporting the hypothetical association between accelerated bone remodeling and bone marrow edema (BME)-like signal intensity on magnetic resonance imaging. BME-like signal is defined as a confluent ill-delimited area of bone marrow with a moderate decrease in signal intensity on fat-sensitive sequences and a high signal intensity on fat-suppressed fluid-sensitive sequences. In addition to this confluent pattern, a linear subcortical pattern and a patchy disseminated pattern have also been recognized on fat-suppressed fluid-sensitive sequences. These particular BME-like patterns may remain occult on T1-weighted spin-echo images. We hypothesize that these BME-like patterns, with particular characteristics in terms of distribution and signal, are associated with accelerated bone remodeling. Limitations in recognizing these BME-like patterns are also discussed

Necrotizing fasciitis: contribution and limitations of diagnostic imaging.

Necrotizing fasciitis is a rare, rapidly spreading, deep-seated infection causing thrombosis of the blood vessels located in the fascia. Necrotizing fasciitis is a surgical emergency. The diagnosis typically relies on clinical findings of severe sepsis and intense pain, although subacute forms may be difficult to recognize. Imaging studies can help to differentiate necrotizing fasciitis from infections located more superficially (dermohypodermitis). The presence of gas within the necrotized fasciae is characteristic but may be lacking. The main finding is thickening of the deep fasciae due to fluid accumulation and reactive hyperemia, which can be visualized using computed tomography and, above all, magnetic resonance imaging (high signal on contrast-enhanced T1 images and T2 images, best seen with fat saturation). These findings lack specificity, as they can be seen in non-necrotizing fasciitis and even in non-inflammatory conditions. Signs that support a diagnosis of necrotizing fasciitis include extensive involvement of the deep intermuscular fascias (high sensitivity but low specificity), thickening to more than 3mm, and partial or complete absence on post-gadolinium images of signal enhancement of the thickened fasciae (fairly high sensitivity and specificity). Ultrasonography is not recommended in adults, as the infiltration of the hypodermis blocks ultrasound transmission. Thus, imaging studies in patients with necrotizing fasciitis may be challenging to interpret. Although imaging may help to confirm deep tissue involvement and to evaluate lesion spread, it should never delay emergency surgical treatment in patients with established necrotizing fasciitis

Update on MRI of spondyloarthritis. part one: the sacro-iliac joint.

In recent years, there has been an increased trend toward the use of advanced medical imaging for the diagnosis and assessment of SpondyloArthritis (SpA) (1, 2). MRI of the sacro-iliac (SI) joints has become a key-imaging technique for the detection of early non-radiographic axial SpA and has been shown to contribute to optimized clinical decision-making (3). The current paper aims at summarizing recent advances in the understanding of the disease, the questions from the clinicians, as well MRI protocols and findings in SpA. Pitfalls and differential diagnosis for SI changes will be addressed

Diagnostic performance of CT-arthrography and 1.5T MR-arthrography for the assessment of glenohumeral joint cartilage: a comparative study with arthroscopic correlation.

PURPOSE: To compare the diagnostic performance of multi-detector CT arthrography (CTA) and 1.5-T MR arthrography (MRA) in detecting hyaline cartilage lesions of the shoulder, with arthroscopic correlation. PATIENTS AND METHODS: CTA and MRA prospectively obtained in 56 consecutive patients following the same arthrographic procedure were independently evaluated for glenohumeral cartilage lesions (modified Outerbridge grade ≥2 and grade 4) by two musculoskeletal radiologists. The cartilage surface was divided in 18 anatomical areas. Arthroscopy was taken as the reference standard. Diagnostic performance of CTA and MRA was compared using ROC analysis. Interobserver and intraobserver agreement was determined by κ statistics. RESULTS: Sensitivity and specificity of CTA varied from 46.4 to 82.4 % and from 89.0 to 95.9 % respectively; sensitivity and specificity of MRA varied from 31.9 to 66.2 % and from 91.1 to 97.5 % respectively. Diagnostic performance of CTA was statistically significantly better than MRA for both readers (all p ≤ 0.04). Interobserver agreement for the evaluation of cartilage lesions was substantial with CTA (κ = 0.63) and moderate with MRA (κ = 0.54). Intraobserver agreement was almost perfect with both CTA (κ = 0.94-0.95) and MRA (κ = 0.83-0.87). CONCLUSION: The diagnostic performance of CTA and MRA for the detection of glenohumeral cartilage lesions is moderate, although statistically significantly better with CTA. KEY POINTS: • CTA has moderate diagnostic performance for detecting glenohumeral cartilage substance loss. • MRA has moderate diagnostic performance for detecting glenohumeral cartilage substance loss. • CTA is more accurate than MRA for detecting cartilage substance loss

Evaluation of rotator cuff tendon tears: comparison of multidetector CT arthrography and 1.5-T MR arthrography.

PURPOSE: To compare the diagnostic performance of multidetector computed tomographic (CT) arthrography and 1.5-T magnetic resonance (MR) arthrography in the evaluation of rotator cuff lesions, with arthroscopic correlation. MATERIALS AND METHODS: This study was approved by the institutional ethical committee, and informed consent was obtained from all patients. CT and MR arthrographic images prospectively obtained in 56 consecutive patients, following the same arthrographic procedure, were independently evaluated by two radiologists. Arthroscopy, performed within 1 month of the imaging, was used as the reference standard. Sensitivity and specificity of CT and MR arthrography were compared by using the McNemar test. Interobserver and intertechnique agreement for detecting rotator cuff lesions were measured and compared with κ and Z statistics. The Bland-Altman method was used to determine interobserver and intertechnique agreement for measuring tendon tears. For grading fatty infiltration of rotator cuff muscles, κ and Z statistics were used. RESULTS: There was no statistically significant difference in sensitivity and specificity between CT arthrography and MR arthrography in depiction of rotator cuff lesions. The respective sensitivity and specificity of CT arthrography were 92% and 93%-97% for the supraspinatus, 100% and 77%-79% for the infraspinatus, 75%-88% and 85%-90% for the subscapularis, and 55%-65% and 100% for the biceps tendon. The respective sensitivity and specificity of MR arthrography were 96% and 83%-93% for the supraspinatus, 88%-100% and 81%-83% for the infraspinatus, 75%-88% and 90%-100% for the subscapularis, and 65%-85% and 100% for the biceps tendon. Interobserver agreement was substantial to almost perfect (κ = 0.744-0.964 for CT arthrography; κ = 0.641-0.893 for MR arthrography), and intertechnique agreement was almost perfect (κ > 0.819). CT and MR arthrography both yielded moderate interobserver and intertechnique agreement for measuring rotator cuff tears and grading muscle fatty infiltration. CONCLUSION: Data suggest that CT and MR arthrography have similar diagnostic performance for the evaluation of rotator cuff tendon tears

Multirater agreement for grading the femoral and tibial cartilage surface lesions at CT arthrography and analysis of causes of disagreement.

To assess the multirater agreement of the modified Outerbridge system for the grading of predefined areas of femorotibial cartilage at CT arthrography with multiple readers, with varying experience. Five readers with varying experience (two junior radiologists, three musculoskeletal radiologists including two experts in cartilage imaging) separately analyzed 962 cartilage sectors from pre-divided knee CT arthrograms with femorotibial osteoarthritis (Kellgren/Lawrence=3). Each cartilage area was graded twice by each reader, at a three-month interval, according to the modified 5-grade Outerbridge system. Interobserver and intraobserver agreement were assessed. After the second reading, 121 areas exhibiting the highest interobserver disagreement were reviewed in consensus to determine the sources of disagreement. The global interobserver agreement was fair (k=0.35), and increased with the grade (from k=0.14 to k=0.76 from grade 0-4). The intraobserver agreement varied with the readers' experience from moderate (k=0.59) to almost perfect (k=0.92). The majority of cases of disagreement (44%) was due to difficulties in assessing the normal variations of cartilage thickness, including diffuse cartilage thinning (23%) and normal variants of cartilage thickness (22%). 32% of cases of disagreement were due to retrospectively avoidable interpretation errors. The multirater agreement of the modified Outerbridge system is only fair when readers of different level of experience are taken into account, and interobserver agreement increases with readers' experience. However, interobserver agreement is substantial for grade 4 lesions. We report normal variations of cartilage thickness that may improve observer agreement in reporting cartilage lesions