Atrophy patterns in isolated subscapularis lesions.

BACKGROUND: While supraspinatus atrophy can be described according to the system of Zanetti or Thomazeau there is still a lack of characterization of isolated subscapularis muscle atrophy. The aim of this study was to describe patterns of muscle atrophy following repair of isolated subscapularis (SSC) tendon. METHODS: Forty-nine control shoulder MRI scans, without rotator cuff pathology, atrophy or fatty infiltration, were prospectively evaluated and subscapularis diameters as well as cross sectional areas (complete and upper half) were assessed in a standardized oblique sagittal plane. Calculation of the ratio between the upper half of the cross sectional area (CSA) and the total CSA was performed. Eleven MRI scans of patients with subscapularis atrophy following isolated subscapularis tendon tears were analysed and cross sectional area ratio (upper half /total) determined. To guarantee reliable measurement of the CSA and its ratio, bony landmarks were also defined. All parameters were statistically compared for inter-rater reliability, reproducibility and capacity to quantify subscapularis atrophy. RESULTS: The mean age in the control group was 49.7 years (± 15.0). The mean cross sectional area (CSA) was 2367.0 mm2 (± 741.4) for the complete subscapularis muscle and 1048.2 mm2 (± 313.3) for the upper half, giving a mean ratio of 0.446 (± 0.046). In the subscapularis repair group the mean age was 56.7 years (± 9.3). With a mean cross sectional area of 1554.7 mm2 (± 419.9) for the complete and of 422.9 mm2 (± 173.6) for the upper half of the subscapularis muscle, giving a mean CSA ratio of 0.269 (± 0.065) which was seen to be significantly lower than that of the control group (p < 0.05). CONCLUSION: Analysis of typical atrophy patterns of the subscapularis muscle demonstrates that the CSA ratio represents a reliable and reproducible assessment tool in quantifying subscapularis atrophy. We propose the classification of subscapularis atrophy as Stage I (mild atrophy) in case of reduction of the cross sectional area ratio < 0.4, Stage II (moderate atrophy) in case of < 0.35 and Stage III (severe atrophy) if < 0.3.

Fluorescence optical imaging and 3T-MRI for detection of synovitis in patients with rheumatoid arthritis in comparison to a composite standard of reference.

OBJECTIVES: To address whether Indocyanine Green (ICG) enhanced fluorescence optical imaging (FOI) is more sensitive than magnetic resonance imaging (MRI) in the detection of synovitis of the wrist and finger joints in rheumatoid arthritis and to analyze the performance of FOI depending on the grade of synovitis. METHODS: Twenty patients with highly active rheumatoid arthritis (mean DAS28-ESR 5.25±1.0) and thirteen healthy volunteers underwent clinical examination, FOI and contrast-enhanced 3T-MRI. Joints were rated by three independent readers semiquantitatively (grade 0-3: no, low, moderate and high grade synovitis) and compared to a semiquantitative composite standard of reference (cSOR, grade 0-3) that incorporated clinical parameters, FOI and MRI results. RESULTS: 2.868 evaluations in 956 joints were performed. FOI had an overall sensitivity of 57.3% and a specificity of 92.1%, whereas MRI had a sensitivity of 89.2% and a specificity of 92.6%. The sensitivity of FOI increased with the degree of synovitis to 65.0% for moderate and severe synovitis (specificity 88.1%) and 76,3% for severe synovitis (specificity 80.5%). The performance of FOI decreased with the degree of synovitis with false negative results predominantly for mild (156/343, 45.5%) and moderate (160/343, 46.6%) synovitis and false positive FOI evaluations predominantly based on weak (grade 1) signals (133/163, 81,6%). CONCLUSION: FOI has a lower sensitivity than 3T-MRI in the detection of synovitis of the hand and finger joints. The diagnostic performance of FOI decreases with the degree of synovitis and with the strength of FOI signals.

Long-term Results After Arthroscopic Repair of Isolated Subscapularis Tears.

BACKGROUND: Although some reports have presented short- to midterm results after arthroscopic repair of isolated subscapularis (SSC) tendon tears, long-term evaluation is still lacking. HYPOTHESIS: Long-term results after arthroscopic repair of isolated SSC tears are comparable with the functional and radiological short- to midterm outcomes described in the literature. STUDY DESIGN: Case series, Level of evidence, 4. METHODS: This study assessed 17 patients (5 females and 12 males; mean age, 45.6 years) with isolated SSC tears (Fox and Romeo classification types 2-4) who underwent all-arthroscopic suture anchor repair. The mean interval from symptom onset to the time of surgery was 5.3 months in 16 patients (94.1%). One patient (5.9%) was symptomatic for a prolonged period (104 months) before surgery. All patients were assessed with a clinical examination preoperatively. SSC function was investigated using specific clinical tests and common scoring systems, including Constant, American Shoulder and Elbow Surgeons (ASES), Disabilities of the Arm, Shoulder and Hand (DASH), and Simple Shoulder Test (SST) scores. At follow-up, muscular strength was evaluated using an electronic force-measuring plate. Structural integrity of the repair was assessed using magnetic resonance imaging (MRI). RESULTS: At a mean follow-up of 98.4 ± 19.9 months, the mean Constant score improved from 47.8 preoperatively to 74.2 postoperatively ( P = .001). Higher Constant ( P = .010) and ASES ( P = .001) scores were significantly associated with a shorter time from symptom onset to surgery. The size of the SSC lesion did not correlate with any clinical score outcome ( P = .476, .449, .985, and .823 for Constant, ASES, DASH, and SST scores, respectively). Three patients (17.6%) had persistent positive clinical test results (belly-press/lift-off). Compared with the uninjured contralateral side, SSC strength was significantly reduced in the belly-press position ( P = .031), although active internal ( P = .085) and external ( P = .093) rotation was not affected. In 1 patient, a rerupture was detected by MRI. Six patients had cranial SSC atrophy. Overall, 88.2% of patients were "very satisfied" or "satisfied" with their results. CONCLUSION: Arthroscopic repair of isolated SSC tears results in significant clinical improvements and enduring tendon integrity, although SSC strength remains reduced in the long term. Early surgical treatment seems to be a relevant factor allowing good shoulder function.

Osteoporosis imaging: effects of bone preservation on MDCT-based trabecular bone microstructure parameters and finite element models.

BACKGROUND: Osteoporosis is defined as a skeletal disorder characterized by compromised bone strength due to a reduction of bone mass and deterioration of bone microstructure predisposing an individual to an increased risk of fracture. Trabecular bone microstructure analysis and finite element models (FEM) have shown to improve the prediction of bone strength beyond bone mineral density (BMD) measurements. These computational methods have been developed and validated in specimens preserved in formalin solution or by freezing. However, little is known about the effects of preservation on trabecular bone microstructure and FEM. The purpose of this observational study was to investigate the effects of preservation on trabecular bone microstructure and FEM in human vertebrae. METHODS: Four thoracic vertebrae were harvested from each of three fresh human cadavers (n=12). Multi-detector computed tomography (MDCT) images were obtained at baseline, 3 and 6 month follow-up. In the intervals between MDCT imaging, two vertebrae from each donor were formalin-fixed and frozen, respectively. BMD, trabecular bone microstructure parameters (histomorphometry and fractal dimension), and FEM-based apparent compressive modulus (ACM) were determined in the MDCT images and validated by mechanical testing to failure of the vertebrae after 6 months. RESULTS: Changes of BMD, trabecular bone microstructure parameters, and FEM-based ACM in formalin-fixed and frozen vertebrae over 6 months ranged between 1.0-5.6% and 1.3-6.1%, respectively, and were not statistically significant (p>0.05). BMD, trabecular bone microstructure parameters, and FEM-based ACM as assessed at baseline, 3 and 6 month follow-up correlated significantly with mechanically determined failure load (r=0.89-0.99; p<0.05). The correlation coefficients r were not significantly different for the two preservation methods (p>0.05). CONCLUSIONS: Formalin fixation and freezing up to six months showed no significant effects on trabecular bone microstructure and FEM-based ACM in human vertebrae and may both be used in corresponding in-vitro experiments in the context of osteoporosis.

Prevalence of and Risk Factors for Dislocation Arthropathy: Radiological Long-term Outcome of Arthroscopic Bankart Repair in 100 Shoulders at an Average 13-Year Follow-up.

BACKGROUND: Glenohumeral osteoarthritis is a well-documented, long-term complication of open stabilization procedures. However, there is a lack of knowledge about long-term radiographic outcome after arthroscopic Bankart procedures. HYPOTHESIS: Glenohumeral osteoarthritis will develop less frequently in arthroscopic Bankart repair compared with open repairs reported in the literature. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The inclusion criteria for this study were (1) all-arthroscopic Bankart repair for a (2) symptomatic anteroinferior shoulder instability and (3) a minimum follow-up of 10 years. True anteroposterior and lateral radiographs were obtained to evaluate the prevalence and grade of osteoarthritis according to the Samilson classification. Patients were assessed by the Constant score and examined for passive external rotation deficits. RESULTS: Of 165 shoulders that fulfilled the inclusion criteria, 100 were available for evaluation. The median Constant score at an average±SD 156.2±18.5 months after Bankart repair was 94 (range, 46-100). Twenty-one shoulders (21%) sustained a recurrent dislocation. Overall, 31% of shoulders showed no evidence of glenohumeral osteoarthritis; 41% showed mild, 16% moderate, and 12% severe degenerative changes. Osteoarthritis did not correlate with Constant score results (P=.427). The grade of osteoarthritis was significantly associated with the number of preoperative dislocations (P=.016), age at initial dislocation (P=.005) and at surgery (P=.002), and the number of anchors used (P=.001), whereas time from initial dislocation to surgery (P=.854) and external rotation deficit at 0° and 90° of abduction (P=.104 and .348, respectively) showed no significant correlation. Recurrent dislocation did not affect the presence or grade of osteoarthritis (P=.796 and .665, respectively). CONCLUSION: At an average 13 years after arthroscopic Bankart repair, osteoarthritic changes are a common finding and, overall, are comparable with reports in the literature regarding open procedures as well as nonoperative treatment. The extent of trauma sustained during preoperative dislocations and the age of the patient seem to be more relevant for long-term dislocation arthropathy than the kind of treatment. Accordingly, the study hypothesis must be rejected. Avoiding preoperative dislocations is more important for the prevention of osteoarthritis than short-term treatment. The number of anchors used was found to be a predictor for long-term development of osteoarthritis.

Validation of a low dose simulation technique for computed tomography images.

PURPOSE: Evaluation of a new software tool for generation of simulated low-dose computed tomography (CT) images from an original higher dose scan. MATERIALS AND METHODS: Original CT scan data (100 mAs, 80 mAs, 60 mAs, 40 mAs, 20 mAs, 10 mAs; 100 kV) of a swine were acquired (approved by the regional governmental commission for animal protection). Simulations of CT acquisition with a lower dose (simulated 10-80 mAs) were calculated using a low-dose simulation algorithm. The simulations were compared to the originals of the same dose level with regard to density values and image noise. Four radiologists assessed the realistic visual appearance of the simulated images. RESULTS: Image characteristics of simulated low dose scans were similar to the originals. Mean overall discrepancy of image noise and CT values was -1.2% (range -9% to 3.2%) and -0.2% (range -8.2% to 3.2%), respectively, p>0.05. Confidence intervals of discrepancies ranged between 0.9-10.2 HU (noise) and 1.9-13.4 HU (CT values), without significant differences (p>0.05). Subjective observer evaluation of image appearance showed no visually detectable difference. CONCLUSION: Simulated low dose images showed excellent agreement with the originals concerning image noise, CT density values, and subjective assessment of the visual appearance of the simulated images. An authentic low-dose simulation opens up opportunity with regard to staff education, protocol optimization and introduction of new techniques.

Measurements and classifications in spine imaging.

Imaging criteria and radiologic measurements play a key role in the diagnosis of spinal diseases. In addition, they often create the basis of classification systems that determine the severity of the disease and thereby enable a stage-related therapy. A clearly defined nomenclature for imaging findings as well as standardized and thoroughly evaluated methods of measurement are necessary to achieve a sufficiently high diagnostic accuracy. Various specialized committees dealing with the diagnosis of spinal diseases have made efforts within the last years to develop diagnostic standards. This review provides an overview of radiologic measurements and classification systems that are currently used for the diagnosis of scoliosis and degenerative diseases of the lumbar spine.

Bone marrow oedema on MR imaging indicates ARCO stage 3 disease in patients with AVN of the femoral head.

OBJECTIVES: To test the hypothesis that bone marrow oedema (BME) observed on MRI in patients with avascular necrosis (AVN) of the femoral head represents an indicator of subchondral fracture. METHODS: Thirty-seven symptomatic hips of 27 consecutive patients (53% women, mean age 49.2) with AVN of the femoral head and associated BME on magnetic resonance (MR) imaging were included. MR findings were correlated with computed tomography (CT) of the hip and confirmed by histopathological examination of the resected femoral head. Imaging studies were analysed by two radiologists with use of the ARCO classification. RESULTS: On MR imaging a fracture line could be identified in 19/37 (51%) cases, which were classified as ARCO stage 3 (n = 15) and stage 4 (n = 4). The remaining 18/37 (49%) cases were classified as ARCO stage 2. However, in all 37/37 (100%) cases a subchondral fracture was identified on CT, indicating ARCO stage 3/4 disease. The extent of subchondral fractures and the femoral head collapse was graded higher on CT as compared to MRI (P < 0.05). Histopathological analysis confirmed bone necrosis and subchondral fractures. CONCLUSIONS: In patients with AVN, BME of the femoral head represents a secondary sign of subchondral fracture and thus indicates ARCO stage 3 disease. KEY POINTS: BME on MRI in AVN of femoral head indicates a subchondral fracture. BME in AVN of the femoral head represents ARCO stage 3/4 disease. CT identifies subchondral fractures and femoral head collapse better than MR imaging. This knowledge helps to avoid understaging and to trigger adequate treatment.

MR arthrography including abduction and external rotation images in the assessment of atraumatic multidirectional instability of the shoulder.

OBJECTIVE: To evaluate diagnostic signs and measurements in the assessment of capsular redundancy in atraumatic multidirectional instability (MDI) of the shoulder on MR arthrography (MR-A) including abduction/external rotation (ABER) images. METHODS: Twenty-one MR-A including ABER position of 20 patients with clinically diagnosed MDI and 17 patients without instability were assessed by three radiologists. On ABER images, presence of a layer of contrast between the humeral head (HH) and the anteroinferior glenohumeral ligament (AIGHL) (crescent sign) and a triangular-shaped space between the HH, AIGHL and glenoid (triangle sign) were evaluated; centring of the HH was measured. Anterosuperior herniation of the rotator interval (RI) capsule and glenoid version were determined on standard imaging planes. RESULTS: The crescent sign had a sensitivity of 57 %/62 %/48 % (observers 1/2/3) and specificity of 100 %/100 %/94 % in the diagnosis of MDI. The triangle sign had a sensitivity of 48 %/57 %/48 % and specificity of 94 %/94 %/100 %. The combination of both signs had a sensitivity of 86 %/90 %/81 % and specificity of 94 %/94 %/94 %. A positive triangle sign was significantly associated with decentring of the HH. Measurements of RI herniation, RI width and glenoid were not significantly different between both groups. CONCLUSIONS: Combined assessment of redundancy signs on ABER position MR-A allows for accurate differentiation between patients with atraumatic MDI and patients with clinically stable shoulders; measurements on standard imaging planes appear inappropriate. KEY POINTS: MR arthrography has the possibility to accurately identify patients with atraumatic MDI. Imaging of the shoulder in abduction and external rotation provides additive information. Capsular enlargement of the shoulder can be diagnosed on MR arthrography.

Early changes of trabecular bone structure in asymptomatic subjects with knee malalignment.

OBJECTIVE: To investigate whether alterations of trabecular bone structure can already be found in young asymptomatic subjects with knee malalignment. METHODS: Forty-eight subjects with neutral, mild varus, severe varus, and valgus knee joint alignment were included in this study (12 subjects in each group). Histomorphometric and texture parameters of the trabecular bone in the medial/lateral femur/tibia were determined using 1.5-T magnetic resonance imaging. RESULTS: Apparent trabecular thickness in the medial tibia compartment was lower in the valgus group (mean ± standard error, 0.353 ± 0.012 mm) compared with the neutral (0.396 ± 0.011 mm; P = 0.043), mild varus (0.403 ± 0.011 mm; P = 0.038) and severe varus groups (0.416 ± 0.013 mm; P = 0.015). In the medial femur compartment, fractal dimension was significantly greater in the mild (1.697 ± 0.005; P = 0.015) and severe varus groups (1.698 ± 0.005; P = 0.036) than in the valgus group (1.674 ± 0.005). CONCLUSIONS: The observed findings may be signs of the adaptation of the subchondral bone to altered loading conditions and possibly of early knee joint impairment.

Synovitis in patients with early inflammatory arthritis monitored with quantitative analysis of dynamic contrast-enhanced optical imaging and MR imaging.

PURPOSE: To evaluate quantitative perfusion measurements of dynamic indocyanine green (ICG)-enhanced optical imaging for monitoring synovitis in the hands of patients with inflammatory arthritis compared with dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging and clinical outcome. MATERIALS AND METHODS: This study was approved by the ethics committee at the institution. Individual joints (n = 840) in the hands and wrists of 28 patients (14 women; mean age, 53.3 years) with inflammatory arthritis were examined at three different time points: before start of therapy and 12 and 24 weeks after start of therapy or therapy escalation. Treatment response was assessed by using clinical measures (simple disease activity index [SDAI]), ICG-enhanced optical imaging, and DCE MR imaging. Dynamic images were obtained for optical imaging and DCE MR imaging. The rate of early enhancement (REE) of the perfusion curves of each joint was calculated by using in-house developed software. Correlation coefficients were estimated to evaluate the associations of changes of imaging parameters and SDAI change. RESULTS: Quantitative perfusion measurements with optical imaging and MR imaging correctly identified patients who responded (n = 18) and did not respond to therapy (n = 10), as determined by SDAI. The difference of REE after 24 weeks of treatment compared with baseline in responders was significantly reduced in optical imaging and MR imaging (optical imaging: mean, -21.5%; MR imaging: mean, -41.0%; P < .001 for both), while in nonresponders it was increased (optical imaging: mean, 10.8%; P = .075; MR imaging: mean, 8.7%; P = .03). The REE of optical imaging significantly correlated with MR imaging (ρ = 0.80; P < .001) and SDAI (ρ = 0.61; P < .001). CONCLUSION: Quantitative analysis of contrast-enhanced optical imaging allows for potential therapeutic monitoring of synovitis in patients with inflammatory arthritis.

Traumatic instability of the elbow - anatomy, pathomechanisms and presentation on imaging.

UNLABELLED: Traumatic instability of the elbow is a common problem among patients presenting to emergency departments. As recurrent instability is more common than previously thought and the knowledge of the most frequent underlying causes increases, treatment of elbow instability is becoming increasingly sophisticated. Therefore, it is mandatory for the radiologist to be familiar with the important osseous and soft-tissue stabilisers of the elbow joint and to know the pathomechanisms that lead to a spectrum of joint instability. This article discusses the relevant anatomy in elbow stability with respect to imaging and function, states the mechanisms leading to elbow dislocation and displays the types of traumatic instability of the elbow on radiography, computed tomography, and magnetic resonance imaging. KEY POINTS: • Expert imaging helps the management of traumatic instability of the elbow • The lateral ulnar collateral ligament is the cornerstone for elbow stability • Soft-tissue disruption is important in posterolateral rotatory instability • Identification of small coronoid process fragments is essential for optimal surgical therapy.

Hepatic angiosarcoma: cross-sectional imaging findings in seven patients with emphasis on dynamic contrast-enhanced and diffusion-weighted MRI.

OBJECTIVE: Primary hepatic angiosarcoma is a very rare and aggressive malignancy of vascular origin. We describe cross-sectional imaging findings of this entity with emphasis on dynamic contrast-enhanced (DCE) and diffusion-weighted (DWI) MR imaging. METHODS: Seven cases of pathologically confirmed hepatic angiosarcoma were retrospectively reviewed (CT and MRI examinations were available in seven and six patients, respectively). Two radiologists evaluated lesion growth patterns, attenuation, signal intensity characteristics, contrast enhancement patterns, and apparent diffusion coefficients (ADCs). RESULTS: Multifocal hepatic disease was present in six patients by means of a mixed pattern of large dominant masses and multiple small nodules; one patient had a solitary large mass. Unenhanced images depicted hemorrhagic areas and a markedly heterogeneous internal architecture within large tumors. Contrast-enhanced early phase images showed variable patterns including patchy peripheral or bizarre shaped intralesional foci of enhancement, peripheral rim enhancement, and small lesions without enhancement. On DCE images, the majority of lesions presented with varying degrees of progressive enhancement. Small nodules frequently displayed homogeneous enhancement on delayed phase images due to complete fill-in. DWI revealed a high interlesional variability of ADC values (range 0.57-2.41 × 10(-3 )mm(2)/s, mean 1.37 × 10(-3 )mm(2)/s). CONCLUSION: Cross-sectional imaging findings of hepatic angiosarcoma reflect the varied histopathological composition of the tumors. Multifocal disease, hemorrhage within large lesions, as well as progressive enhancement on DCE images are typical features of hepatic angiosarcoma. The mean ADC of lesions was found to be slightly elevated in comparison with other hepatic malignancies.

Lesions of the biceps pulley: diagnostic accuracy of MR arthrography of the shoulder and evaluation of previously described and new diagnostic signs.

PURPOSE: To retrospectively determine the diagnostic accuracy of magnetic resonance (MR) arthrography of the shoulder in the evaluation of lesions of the biceps pulley and to evaluate previously described and new diagnostic signs. MATERIALS AND METHODS: Institutional review board approval was obtained; the requirement for informed consent was waived. MR arthrograms of 80 consecutive patients (mean age, 34.2 years; 53 male, 27 female) with arthroscopically proved intact or torn pulley systems were assessed for the presence of a pulley lesion by three radiologists who were blinded to arthroscopic results. Criteria evaluated were displacement of the long head of the biceps tendon (LHBT) relative to the subscapularis tendon on oblique sagittal images (displacement sign), medial subluxation of the LHBT on transverse images, nonvisibility or discontinuity of the superior glenohumeral ligament (SGHL), presence of biceps tendinopathy, and rotator cuff tears adjacent to the rotator interval. RESULTS: There were 28 pulley lesions noted at arthroscopy. For observers 1, 2, and 3, respectively: MR arthrography showed a sensitivity of 89%, 86%, and 82% and a specificity of 96%, 98%, and 87% in the detection of pulley lesions. Nonvisibility or discontinuity of the SGHL was sensitive (79%, 89%, and 79%) and specific (83%, 79%, and 75%). With the displacement sign, sensitivity was 86%, 82%, and 75% and specificity was 96%, 98%, 90%. Tendinopathy of the LHBT on oblique sagittal images showed a sensitivity of 93%, 82%, 64%; specificity was 81%, 96%, and 85%. Subluxation of the LHBT was insensitive (36%, 50%, and 64%) but specific (100%, 98%, and 96%). CONCLUSION: MR arthrography is accurate in the detection of pulley lesions; the displacement sign, nonvisibility or discontinuity of the SGHL, and tendinopathy of the LHBT on oblique sagittal images are the most accurate criteria for the detection of pulley lesions.

Detection of synovitis in the hands of patients with rheumatologic disorders: diagnostic performance of optical imaging in comparison with magnetic resonance imaging.

OBJECTIVE: To prospectively compare an indocyanine green (ICG)-enhanced optical imaging system with contrast-enhanced magnetic resonance imaging (MRI) for the detection of synovitis in the hands of patients with rheumatologic disorders. METHODS: Forty-five patients (30 women [67%], mean ± SD age 52.6 ± 13.4 years) in whom there was a clinical suspicion of an inflammatory arthropathy were examined with a commercially available device for ICG-enhanced optical imaging as well as by contrast-enhanced 3T MRI as the standard of reference. Three independent readers graded the degree of synovitis in the carpal, metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints of both hands (1,350 joints), using a 4-point ordinate scale (0 = no synovitis, 1 = mild, 2 = moderate, 3 = severe). Statistical analyses were performed using a logistic generalized estimating equation approach. Agreement of optical imaging ratings made by the different readers was estimated with a weighted kappa coefficient. RESULTS: When MRI was used as the standard of reference, optical imaging showed a sensitivity of 39.6% (95% confidence interval [95% CI] 31.1-48.7%), a specificity of 85.2% (95% CI 79.5-89.5%), and accuracy of 67.0% (95% CI 61.4-72.1%) for the detection of synovitis in patients with arthritis. Diagnostic accuracy was especially limited in the setting of mild synovitis, while it was substantially better in patients with severely inflamed joints. Moderate interreader and intrareader agreement was observed. CONCLUSION: The evaluated ICG-enhanced optical imaging system showed limitations for the detection of inflamed joints of the hand in comparison with MRI.

Avascular necrosis following fracture-dislocation of the hip and spontaneous relocation.

Injuries occurring during soccer tend to occur with lower energy transfer than in some other contact sports. Tibial and femoral shaft fractures occasionally occur, but pelvic fractures are rare. We report a case of a missed posterior acetabular rim fracture, caused by a low energy trauma playing soccer, complicated by the development of avascular necrosis (AVN) of the femoral head and subsequent osteoarthritis.

Hepatic epithelioid hemangioendothelioma: findings at CT and MRI including preliminary observations at diffusion-weighted echo-planar imaging.

OBJECTIVE: Hepatic epithelioid hemangioendothelioma (EHE) is a rare vascular tumor with low- to intermediate-grade malignant potential. We describe cross-sectional imaging findings of pathologically confirmed EHE including preliminary observations on lesion characteristics and apparent diffusion coefficients (ADCs) at diffusion-weighted MR imaging (DWI). METHODS: CT and MRI examinations in five patients were retrospectively reviewed. Two radiologists evaluated lesion growth patterns, attenuation, signal intensity characteristics, and contrast enhancement patterns. Additionally, DWI features on low and high b-value images as well as ADCs were assessed in three patients. RESULTS: Imaging features of EHE included multifocal hepatic disease (n = 5), predominantly subcapsular location (n = 5), coalescence of nodules (n = 5), capsular retraction (n = 3), and intralesional calcifications (n = 3). Contrast-enhanced CT and MR images showed variable degrees of peripheral rim enhancement. T2-weighted MR images, low b-value DWI and ADC maps frequently depicted a "target-sign" appearance of tumor nodules. A markedly hyperintense central area corresponding to hypocellular stroma was surrounded by a moderately hyperintense outer rim reflecting hypercellular tumor regions. The mean ADC of lesions was 1.86 × 10(-3) mm(2)/s. CONCLUSION: Cross-sectional imaging displayed typical features of EHE. The mean ADC value of lesions was found to be relatively high in comparison with other hepatic malignancies, which may be helpful in suggesting the diagnosis.

Inter- and intraobserver variability of MR arthrography in the detection and classification of superior labral anterior posterior (SLAP) lesions: evaluation in 78 cases with arthroscopic correlation.

PURPOSE: The purpose of this study was to determine inter- and intraobserver variability of MR arthrography of the shoulder in the detection and classification of superior labral anterior posterior (SLAP) lesions. METHODS: MR arthrograms of 78 patients who underwent MR arthrography before arthroscopy were retrospectively analysed by three blinded readers for the presence and type of SLAP lesions. MR arthrograms were reviewed twice by each reader with a time interval of 4 months between the two readings. Inter- and intraobserver agreement for detection and classification of SLAP lesions were calculated using kappa coefficients. RESULTS: Arthroscopy confirmed 48 SLAP lesions: type I (n = 4), type II (n = 37), type III (n = 3), type IV (n = 4). Sensitivity and specificity for detecting SLAP lesions with MR arthrography for each reader were 88.6%/93.3%, 90.9%/80.0% and 86.4%/76.7%. MR arthrographic and arthroscopic grading were concurrent for 72.7%, 68.2% and 70.5% of SLAP lesions for readers 1-3, respectively. Interobserver agreement was excellent (kappa = 0.82) for detection and substantial (kappa = 0.63) for classification of SLAP lesions. For each reader intraobserver agreement was excellent for detection (kappa = 0.93, kappa = 0.97, kappa = 0.97) and classification (kappa = 0.94, kappa = 0.84, kappa = 0.93) of SLAP lesions. CONCLUSION: MR arthrography allows reliable and accurate detection of SLAP lesions. In addition, SLAP lesions can be diagnosed and classified with substantial to excellent inter- and intraobserver agreement.

Diagnosis of hepatic metastasis: comparison of respiration-triggered diffusion-weighted echo-planar MRI and five t2-weighted turbo spin-echo sequences.

OBJECTIVE: The purpose of this study was to compare the value of respiration-triggered diffusion-weighted (DW) single-shot echo-planar MRI (EPI) and five variants of T2-weighted turbo spin-echo (TSE) sequences in the diagnosis of hepatic metastasis. MATERIALS AND METHODS: Fifty-two patients with extrahepatic primary malignant tumors underwent 1.5-T MRI that included DW EPI and the following variants of T2-weighted TSE techniques: breath-hold fat-suppressed HASTE, breath-hold fat-supressed TSE, respiration-triggered fat-suppressed TSE, breath-hold STIR, and respiration-triggered STIR. Images were reviewed independently by two blinded observers who used a 5-point confidence scale to identify lesions. Results were correlated with surgical and histopathologic findings and follow-up imaging findings. The accuracy of each technique was measured with free-response receiver operating characteristic analysis. RESULTS: A total of 118 hepatic metastatic lesions (mean diameter, 12.8 mm; range, 3-84 mm) were evaluated. Accuracy values were higher (p < 0.001) with DW EPI (0.91-0.92) than with the T2-weighted TSE techniques (0.47-0.67). Imaging with the HASTE sequence (0.47-0.52) was less accurate (p < 0.05) than imaging with the breath-hold TSE, breath-hold STIR, respiration-triggered TSE, and respiration-triggered STIR sequences (0.59-0.67). Sensitivity was higher (p < 0.001) with DW EPI (0.88-0.91) than with T2-weighted TSE techniques (0.45-0.62). For small (< or = 10 mm) metastatic lesions only, the differences in sensitivity between DW EPI (0.85) and T2-weighted TSE techniques (0.26-0.44) were even more pronounced. CONCLUSION: DW EPI was more sensitive and more accurate than imaging with T2-weighted TSE techniques. Because of the black-blood effect on vessels and low susceptibility to motion artifacts, DW EPI was particularly useful for the detection of small (< or = 10 mm) metastatic lesions.