Comparison of Three-Dimensional Isotropic and Two-Dimensional Conventional Indirect MR Arthrography for the Diagnosis of Rotator Cuff Tears

OBJECTIVE: To compare the accuracy between a three-dimensional (3D) indirect isotropic T1-weighted fast spin-echo (FSE) magnetic resonance (MR) arthrography and a conventional two-dimensional (2D) T1-weighted sequences of indirect MR arthrography for diagnosing rotator cuff tears. MATERIALS AND METHODS: The study was approved by our Institutional Review Board. In total, 205 patients who had undergone indirect shoulder MR arthrography followed by arthroscopic surgery for 206 shoulders were included in this study. Both conventional 2D T1-weighted FSE sequences and 3D isotropic T1-weighted FSE sequence were performed in all patients. Two radiologists evaluated the images for the presence of full- or partial-thickness tears in the supraspinatus-infraspinatus (SSP-ISP) tendons and tears in the subscapularis (SSC) tendons. Using the arthroscopic findings as the reference standard, the diagnostic performances of both methods were analyzed by the area under the receiver operating characteristic curve (AUC). RESULTS: Arthroscopy confirmed 165 SSP-ISP tendon tears and 103 SSC tendon tears. For diagnosing SSP-ISP tendon tears, the AUC values were 0.964 and 0.989 for the 2D sequences and 3D T1-weighted FSE sequence, respectively, in reader I and 0.947 and 0.963, respectively, in reader II. The AUC values for diagnosing SSC tendon tears were 0.921 and 0.925, respectively, for reader I and 0.856 and 0.860, respectively, for reader II. There was no significant difference between the AUC values of the 2D and 3D sequences in either reader for either type of tear. CONCLUSION: 3D indirect isotropic MR arthrography with FSE sequence and the conventional 2D arthrography are not significantly different in terms of accuracy for diagnosing rotator cuff tears.

Anatomy, Variants, and Pathologies of the Superior Glenohumeral Ligament: Magnetic Resonance Imaging with Three-Dimensional Volumetric Interpolated Breath-Hold Examination Sequence and Conventional Magnetic Resonance Arthrography

The purpose of this review was to demonstrate magnetic resonance (MR) arthrography findings of anatomy, variants, and pathologic conditions of the superior glenohumeral ligament (SGHL). This review also demonstrates the applicability of a new MR arthrography sequence in the anterosuperior portion of the glenohumeral joint. The SGHL is a very important anatomical structure in the rotator interval that is responsible for stabilizing the long head of the biceps tendon. Therefore, a torn SGHL can result in pain and instability. Observation of the SGHL is difficult when using conventional MR imaging, because the ligament may be poorly visualized. Shoulder MR arthrography is the most accurately established imaging technique for identifying pathologies of the SGHL and associated structures. The use of three dimensional (3D) volumetric interpolated breath-hold examination (VIBE) sequences produces thinner image slices and enables a higher in-plane resolution than conventional MR arthrography sequences. Therefore, shoulder MR arthrography using 3D VIBE sequences may contribute to evaluating of the smaller intraarticular structures such as the SGHL.

Hill-Sachs Lesion on MR Arthrography of the Shoulder: Relationship with Bankart Lesion on Arthroscopy and Frequency of Shoulder Dislocations

PURPOSE: This study was performed to evaluate the presence and severity of Hill-Sachs (HS) lesions on MR arthrography (MRA) of shoulder in patients with Bankart lesions following anterior dislocation and to investigate their relationship with Bankart lesions and frequency of dislocations. MATERIALS AND METHODS: 86 MRA of shoulder were evaluated in patients with arthroscopic Bankart repairs following anterior dislocations. The largest surface length of HS lesion on MRA and extent of Bankart lesions on arthroscopy were measured. Relationships between length of HS lesions and extent of Bankart lesions and frequency of dislocations were assessed. RESULTS: HS lesions were identified on MRA in 78 patients. The largest surface length of HS lesion ranged from 9.3 mm to 29.6 mm (mean, 18.8 mm). The extent of Bankart lesion ranged from one to six o'clock extent (mean, 4.25 o'clock extent). Three patients had single dislocation and the other 75 patients had recurrent dislocations (mean 24.5 times). The largest surface length of HS lesions was positively correlated with extent of Bankart lesions (p = 0.001, r = 0.37), but not with frequency of dislocation. CONCLUSION: HS lesion was very common in patients with Bankart lesion. The severity of HS lesions was correlated with extent of Bankart lesions.

Magnetic Resonance Arthrographic Dissection of Posterolateral Corner of the Knee: Revealing the Meniscofibular Ligament

PURPOSE: To evaluate meniscofibular ligament (MFibL) at the posterolateral corner of the knee joint on the magnetic resonance arthrography (MRA) with 70degrees knee flexion. MATERIALS AND METHODS: The MRA of the knee joint was performed at 70degrees knee flexion. Eighteen patients (19 knee joints) underwent scanning of sagittal, coronal, and axial fat-suppressed T1 weighted images (T1FS), and coronal fat-suppressed T2 weighted images. Sagittal three-dimensional (3D) gradient echo (GRE) images were also obtained. Retrospective review of 19 knee MRA studies was independently performed by two musculoskeletal radiologists. The statistical significance was proved by chi-square test. RESULTS: The MFibL ligament was optimally demonstrated on the far lateral sagittal 3D GRE and T1FS MRA images. The MFibL appeared as a curvilinear or straight hypointense band of variable thickness, extended from the posterolateral meniscus to upper anteromedial aspect of the fibular head. The MFibL was demonstrated with scale 2 (more than a half length of the ligament) by both reviewers in 73.68% (n=14/19) of the knee 3D GRE images and 89.47% (n=17/19) of the knee T1FS images. The visualization on T1FS and that on GRE were not statistically different from each other (p>0.05). The interobserver agreements were significantly good on both 3D GRE and T1FS images in detecting the ligament (kappa values, 0.642 and 0.683, respectively). CONCLUSION: The MFibL is well visualized on the far lateral sagittal MRA at 70degrees knee flexion, which could potentially be useful in recognizing structures in the posterolateral corner of the knee, including the MFibL.

Comparisons of the Various Partial-Thickness Rotator Cuff Tears on MR Arthrography and Arthroscopic Correlation

OBJECTIVE: To assess the diagnostic performance of MR arthrography in the diagnosis of the various types of partial-thickness rotator cuff tears by comparing the MR imaging findings with the arthroscopic findings. MATERIALS AND METHODS: The series of MR arthrography studies included 202 patients consisting of 100 patients with partial-thickness rotator cuff tears proved by arthroscopy and a control group of 102 patients with arthroscopically intact rotator cuffs, which were reviewed in random order. At arthroscopy, 54 articular-sided, 26 bursal-sided, 20 both articular- and bursal-sided partial-thickness tears were diagnosed. The MR arthrographies were analyzed by two radiologists for articular-sided tears, bursal-sided tears, and both articular- and bursal-sided tears of the rotator cuff. The sensitivity and specificity of each type of partial-thickness tears were determined. Kappa statistics was calculated to determine the inter- and intra-observer agreement of the diagnosis of partial-thickness rotator cuff tears. RESULTS: The sensitivity and specificity of the various types of rotator cuff tears were 85% and 90%, respectively for articular-sided tears, 62% and 95% for bursal-sided tears, as well as 45% and 99% for both articular- and bursal-sided tears. False-negative assessments were primarily observed in the diagnosis of bursal-sided tears. Conversely, both articular- and bursal-sided tears were overestimated as full-thickness tears. Inter-observer agreement was excellent for the diagnosis of articular-sided tears (k = 0.70), moderate (k = 0.59) for bursal-sided tears, and fair (k = 0.34) for both articular- and bursal-sided tears, respectively. Intra-observer agreement for the interpretation of articular- and bursal-sided tears was excellent and good, respectively, whereas intra-observer agreement for both articular- and bursal-sided tears was moderate. CONCLUSION: MR arthrography is a useful diagnostic tool for partial-thickness rotator cuff tears, but has limitations in that it has low sensitivity in bursal- and both articular- and bursal-sided tears. In addition, it shows only fair inter-observer agreement when it comes to predicting both articular- and bursal-sided tears.

The Relationship between the Evaluation of the Graft-bone Interface and the Clinical Results after Double Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE: This study examined the relationship between an evaluation of the graft-bone interface using magnetic resonance (MR) arthrography and the clinical results after double bundle anterior cruciate ligament (ACL) reconstruction. MATERIALS AND METHODS: From December 2005 to October 2007, 15 cases that underwent double bundle ACL reconstruction and that were evaluated by MR arthrography were reviewed. The mean follow-up period was 20 months. The graft-bone interface was assessed by the leakage of contrast medium seen on MR arthrography. Four groups were classified according to the degree of contrast media leakage: no contrast media leakage, the focal type, the crescent type and the circumferential type. A functional evaluation was made using the Lysholm score, the international knee documentation committee (IKDC) score, the difference in the midthigh circumference and the Hop test. The stability was evaluated using a Lachmann test, a pivot shift test, a KT-2000 arthrometer and an anterior drawer stress radiograph using Telos(R) with the knee in 30degrees flexion. RESULTS: Ten cases showed no leakage of contrast media, five cases showed focal leakage and there was no case of crescent and circumferential leakage. The clinical results of the no leakage and focal leakage groups were compared. The functional evaluation such as the Lysholm score, the IKDC score, the difference in the midthigh circumference and the Hop test showed no significant difference between the two groups. The stability evaluation, such as the Lachmann test, the pivot shift test, the KT-2000 arthrometer and anterior drawer stress radiograph, also showed no significant difference. CONCLUSION: On MR arthrography after double bundle ACL reconstruction, adequate osteointegration and satisfactory clinical results could be obtained in the no leakage and focal leakage groups.

Comparative Study of MR-arthrography and Arthroscopy in Partial Thickness Rotator Cuff Tears

PURPOSE: The purpose of this study was to assess the efficacy of MR arthrography to detect partial thickness rotator cuff tears. MATERIALS AND METHODS: One hundred and seventy seven patients with a high suspicion for rotator cuff disease were studied by performing MR-arthrography and subsequent arthroscopy. The ability of MRarthrography to detect partial thickness tears was evaluated according to the location of the tears. We determined the correspondence between the measurements of the articular side partial tears on MR arthrography and those on the arthroscopic findings. RESULTS: The arthroscopic diagnosis of partial thickness rotator cuff tears was divided into 3 groups according to their location. There were 63 cases on the articular side, 41 cases on the bursal side and 20 cases on both sides. The sensitivity of MR-arthrography was 82% for the articular side tears and 11% for the bursal tears. The specificity was 88% for the articular side tears and 100% for the bursal tears. MRarthrographic measurement correctly predicted 72% in 28 repaired cases of 56 articular side partial thickness tears. CONCLUSIONS: MR-arthrography may be a reliable tool for diagnosing articular side partial thickness rotator cuff tears, but it has limitations for bursal side tears.

The Usefulness of Multidetector CT Arthrography in the Diagnosis of Shoulder Pathology: Comparison with MR Arthrography and Arthroscopic Findings in the Same Patient

PURPOSE: The purpose of the study is to evaluate the usefulness of CT arthrography (CTA) by conducting a comparative study of CTA and MR arthrography (MRA) with the arthroscopic findings in the same patients. MATERIALS AND METHODS: Forty nine patients who suffered from shoulder disease underwent MRA and CTA concurrently. The sensitivity and specificity of CTA was evaluated, as compared to MRA, in the case of four types of shoulder pathological lesions. The accuracy of CTA was evaluated by analyzing the arthroscopic findings of thirty four patients. RESULTS: Compared to MRA, CTA showed a sensitivity of 90% and a specificity of 100% for diagnosing supraspinatus tendon (SST) full thickness tear, and CTA showed a sensitivity of 100% and a specificity of 97.5% for making the diagnosis of superior labrum anterior to posterior (SLAP) lesion. For diagnosing partial articular side supraspinatus avulsion (PASTA) lesion, some studies have shown the usefulness of CTA with a sensitivity of 71.4% and a specificity of 97.7%. However, for diagnosing SST bursal side partial tear, the sensitivity of CTA was as low as 10%. CTA has been shown to be relatively accurate when the diagnoses were verified with the arthroscopic findings; diagnosing SST full thickness tear and SLAP lesion with CTA has shown an accuracy of 100% and87.5% respectively, and CTA showed 71.4% diagnostic accuracy for PASTA lesion. CONCLUSION: CTA was a useful tool and it was equivalent to MRA for the assessment of SST full thickness tear, SLAP lesion and PASTA lesion, but not bursal side partial tear. Thus, it may be used preferably to diagnose shoulder pathology and for follow up as an inexpensive tool after operation.

Magnetic Resonance Arthrographic Findings of the Painful Hemiplegic Shoulder

OBJECTIVE: To identify the etiology of hemiplegic shoulder pain by magnetic resonance (MR) arthrography. METHOD: The study included seventy-four hemiplegic patients with shoulder pain. After several physical examinations, all patients had fluoroscopically guided injection by a physiatrist with a maximum of 12~15 ml of contrast agent. Then T1-weighted, T2-weighted and fat-suppressed T1-weighted images were taken at the oblique coronal plane. In addition, fat-suppressed T1-weighted images were obtained at the oblique sagittal and oblique coronal plane. RESULTS: Except for the 9 patients who did not finish the study, the mean age of the participants was 61.5+/-8.9 years and mean duration of the cerebrovascular accident (CVA) was 15.7+/-9.7 weeks. The findings were as follows: 40% supraspinatus tendinitis, 30.8% superior labrum anterior to posterior (SLAP) lesion, 29.2% adhesive capsulitis, 24.6% supraspinatus partial tear, 23.1% biceps tendinitis, 13.8% supraspinatus full thickness tear, 7.7% infraspinatus partial tear. The SLAP lesion had significant statistic relationship with biceps tendinitis (p<0.05) but not with rotator cuff lesion. CONCLUSION: We found that causes of hemiplegic shoulder pain were various. The prevalence of the SLAP lesion was high (30.8%). We recommend the MR arthrography when the hemiplegic shoulder pain does not improve by conventional therapy or the cause of the pain is uncertain.

Optimization of the Contrast Mixture Ratio for Simultaneous Direct MR and CT Arthrography: an in Vitro Study

OBJECTIVE: This study was designed to determine the optimal mixture ratio of gadolinium and iodinated contrast agent for simultaneous direct MR arthrography and CT arthrography. MATERIALS AND METHODS: An in vitro study was performed utilizing mixtures of gadolinium at six different concentrations (0.625, 1.25, 2.5, 5.0, 10 and 20 mmol/L) and iodinated contrast agent at seven different concentrations (0, 12.5, 25, 37.5, 50, 75 and 92-99.9%). These mixtures were placed in tissue culture plates, and were then imaged with CT and MR (with T1-weighted sequences, proton-density sequences and T2-weighted sequences). CT numbers and signal intensities were measured. Pearson's correlation coefficients were used to assess the correlations between the gadolinium/iodinated contrast agent mixtures and the CT numbers/MR signal intensities. Scatter diagrams were plotted for all gadolinium/iodinated contrast agent combinations and two radiologists in consensus identified the mixtures that yielded the optimal CT numbers and MR signal intensities. RESULTS: The CT numbers showed significant correlation with iodinated contrast concentrations (r = 0.976, p < 0.001), whereas the signal intensities as measured on MR images showed a significant correlation with both gadolinium and iodinated contrast agent concentrations (r = -484 to -0.719, p < 0.001). A review of the CT and MR images, graphs, and scatter diagram of 42 combinations of the contrast agent showed that a concentration of 1.25 mmol/L gadolinium and 25% iodinated contrast agent was the best combination for simultaneous CT and MR imaging. CONCLUSION: A mixture of 1.25 mmol/L gadolinium and 25% iodinated contrast agent was found to be optimal for simultaneous direct MR arthrography and CT arthrography.

Superior Labrum Anterior to Posterior Lesion Type II with Accompanied Findings: Assessment of Shoulder MR Arthrographic Findings

PURPOSE: To describe the pattern of various shoulder abnormalities with an associated superior labrum anterior to posterior (SLAP) lesion type II using magnetic resonance (MR) arthrography, and to assess the clinical significance of the associated abnormalities. MATERIALS AND METHODS: A retrospective review of the MR arthrographic findings of 92 cases of a shoulder with an arthroscopically confirmed SLAP lesion type II was performed. The MR arthrography images were reviewed and analyzed. MR arthrographic analysis noted the presence of a rotator cuff abnormality, acromioclavicular arthritis, adhesive capsulitis, glenohumeral arthritis, a labral abnormality besides the SLAP lesion, and a paralabral cyst. The patients with SLAP lesions were divided into two age groups: those over 40 years of age and those forty years old or younger. Statistical analysis was performed to evaluate the influence of age on the various shoulder abnormalities with associated SLAP lesion. RESULTS: Of the 92 SLAP lesions type II, there were 7 cases (8%) of isolated SLAP lesions without any associated any shoulder abnormality. Eighty-five (92%) SLAP lesions were associated with various shoulder abnormalities including rotator cuff tendinosis (30/92, 33%), partial-thickness tear (36/92, 39%), full-thickness tear (2/92, 2%), acromioclavicular arthritis (46/92, 50%), adhesive capsulitis (7/92, 8%), glenohumeral arthritis (15/92, 16%), labral abnormality (26/92, 28 %) and paralabral cyst (7/92, 8%). The SLAP lesions (60/92, 65%) in patients over forty years of age were accompanied by a significantly high number of rotator cuff abnormalities (p < 0.001), glenohumeral osteoarthritis (p = 0.001), and acromioclavicular osteoarthritis (p < 0.001). In contrast, the SLAP lesions (32/92, 35%) in patients forty years old or younger had a significantly high number of anterior or posterior labral lesions (p < 0.001). CONCLUSION: Isolated SLAP lesions type II without other associated shoulder abnormalities are uncommon, and the age of the patient influences the prevalence of other shoulder abnormalities associated with SLAP lesions. In addition, MR arthrography can help detect shoulder abnormalities accompanying the SLAP lesions.

Feasibility of Ultrasound-Guided Intraarticular Contrast Injection for MR Arthrography

PURPOSE: To assess the feasibility of ultrasound-guided intraarticular contrast injection using the posterior approach for MR arthrography. MATERIALS AND METHODS: Between June 2002 and October 2004, 132 patients (29 female, 103 male: mean age, 33.6 years) underwent ultrasound-guided intraarticular contrast media injection (40 ml saline+10 ml 2% lidocaine(R)+0.2 ml gadopentetate dimeglumine+0.4 ml epinephrine(R) for MR arthrography. The patients were classified into four groups, viz. the no leakage group, the minor leakage with successful intraarticular injection group, the major leakage with unsuccessful intraarticular injection group, and the injection failure group. RESULTS: The "no leakage" and "minor leakage" groups were considered to be technical successes, while the "major leakage" and "injection failure" groups were regarded as technical failures. The technical success rate of ultrasound-guided intraarticular contrast injection using the posterior approach for MR Arthrography was 99.2% (131/132 patients) and one patient 0.7% (1/132 patients) was included in the "major leakage" group. CONCLUSION: Ultrasound-guided intraarticular contrast injection using the posterior approach for MR arthrography was feasible with a high success rate.

Adhesive Capsulitis of the Shoulder: MR Arthrography

PURPOSE: Adhesive capsulitis is a clinical syndrome involving pain and decreased joint motion caused by thickening and contraction of the joint capsule. The purpose of this study is to describe the MR arthrographic findings of this syndrome. MATERIALS AND METHODS: Twenty-nine sets of MR arthrographic images were included in the study. Fourteen patients had adhesive capsulitis diagnosed by physical examination and arthrography, and their MR arthrographic findings were compared with those of 15 subjects in the control group. The images were retrospectively reviewed with specific attention to the thickness of the joint capsule, volume of the axillary pouch (length, width, height(depth)), thickness of the coracohumeral ligament, presence of extra-articular contrast extravasation, and contrast filling of the subcoracoid bursa. RESULTS: Mean capsular thickness measured at the inferior portion of the axillary pouch was 4.1 mm in patients with adhesive capsulitis and 1.5 mm in the control group. The mean width of the axillary pouch was 2.5 mm in patients and 9.5 mm in controls. In patients, the capsule was significantly thicker and the axillary pouch significantly narrower than in controls (p<0.05). Capsule thickness greater than 2.5 mm at the inferior portion of the axillary pouch (sensitivity 93%, specificity 80%) and a pouch narrower than 3.5 mm (sensitivity 93%, specificity 100%) were useful criteria for the diagnosis of adhesive capsulitis. In patients with this condition, extra-articular contrast extravasation was noted in six patients (43%) and contrast filling of the subcoracoid bursa in three (21%). CONCLUSION: The MR arthrographic findings of adhesive capsulitis are capsular thickening, a low-volume axillary pouch, extra-articular contrast extravasation, and contrast filling of the subcoracoid bursa. Capsule thickness greater than 2.5 mm at the inferior portion of the axillary pouch and a pouch width of less than 3.5 mm are useful diagnostic imaging characteristics.

Anterior Labral Tear: Diagnostic Value of MR Arthrography of the Shoulder

PURPOSE: To assess the accuracy of magnetic resonance(MR) arthrography in the diagnosis of anterior labral tear of the shoulder. MATERIALS AND METHODS: Between Semptember 1996 and February 2000, MR arthrography of the shoulder was performed in 281 patients with a history of shoulder pain or instability. Among this total, only 157 shoulders in 154 patients who underwent arthroscopy or open surgery 0 to 230 (average, 20.9) days after MR arthrography were included in this study; the subjects comprised of 150 males and 4 females with an average age of 23.3 years. MR arthrographs of these 154 patients were analyzed for the presence of anterior labral tears, and the findings were correlated with the arthroscopic and surgical findings. Anterior labral tear was classified as A to D according to its location, as determined by arthroscopy and surgery. (A=4 to 6 o 'clock direction, anteroinferior; B=2 to 4 o 'clock direction, central; C=12 to 2 o 'clock direction, anterosuperior; D= SLAP lesions). The retrospective analysis of MR arthrographs showing false-positive and negative findings was also undertaken. RESULTS: In the diagnosis of anterior labral tear, MR arthrography showed a sensitivity of 94%, a specificity of 90% and an accuracy of 91%. Anterior labral tears were confirmed by arthroscopy or surgery in 62 of the 157 shoulders (39%). Among 62 lesions, two (3%) were observed in area A, 32(52%) in area A+B, nine (15%) in area A+B+C, one(2%) in area A+B+D, 13(21%) in area A+B+C+D, two (3%) in area B+C, one(2%) in area B+D, and two(3%) in area C. Among ten false-positive cases, seven were focal lesions (two, three and two lesions in area A, B and C, respectively), and in the remaining three cases, located in area A+B, MR arthrography revealed thickening and deformation. All four false negatives were focal lesions (two in area A and two in area C). CONCLUSION: Other than in focal lesions, in which accuracy was relatively low, MR arthrography showed high sensitivity, specificity and accuracy in the diagnosis of anterior labral tear of the shoulder.

A Study to Assess by Means of MR Arthrography the Causal Relationship between Anterior Capsular Attachment Typeand Anterior Instability of the Glenohumeral Joint

PURPOSE: To evaluate by means of MR arthrography the causal relationship between anterior capsularattach-ment type and anterior instability of the glenohumeral joint. MATERIALS AND METHODS: Sixty-five patients (M:F=64:1; mean age, 23 years), who had undergone shoulder MR arthrography were retrospectively reviewed. There wasno history of traumatic dislocation, and medical records relating to anterior instability were available. Physicalexamination revealed anterior instability in 25 patients(Group A), while in 40 (Group B), this was eithersuspicious or absent. With the aid of general anesthe-sia, 32 patients who had undergone surgery were physicallyexamined. Anterior instability was evident in 16 patients(Group C), and suspicious or absent in the remaining 16(Group D). All images were obtained after in-traarticular injection of Gd-DTPA. Fat-suppressed T1 axial imagingwas used to evaluate anterior capsular at-tachment type at mid and distal three-fourths levels of the glenoidfossa. The causal relationship between ante-rior capsular attachment types and anterior instability was analyzedusing the x2 test RESULTS: In group A, type I was most common at distal three-fourths level, and types I and IIwere equal and more common than type III at mid level. In group B, type I anterior capsular attachment type wasmost com-mon at both mid and distal three-fourths level. In these groups, no statistical significance was notedbetween anterior capsular attachment type and anterior instability (p value 0.611: 0.567). In group C, types I andII were equal and more common than type III at both mid and distal three-fourths level, while in group D, type IIwas most common at mid level, and type I was most common at distal three-fourths level. In these groups, nostatistical significance was noted between anterior capsular attachment type and anterior instability (p val-ue,0.772). CONCLUSION: There was no statistically significant difference between anterior capsular attachment typeand anterior instability of the shoulder joint.

Efficacy of MR Arthrography in the Diagnosis of the Acetabular Labral Tear

PURPOSE: To determine the accuracy of magnetic resonance (MR) arthrography in the detection and staging of lesions of the acetabular labrum. MATERIALS AND METHODS: Fifteen hips of 14 patients with chronic hip pain and clinical suspicion of labral lesions were examined with direct or indirect MR arthrography and underwent subsequent arthroscopic evaluation. The study population consisted of six women and eight men aged between 40 and 59 years. Nine arthrograms were obtained intra-articular administration of gadolinium solution, and six involved articular motion exercise after intravenous administration of gadolinium solution. In 14 cases a phased-array pelvic coil was used, and a shoulder coil in one. Fat-suppressed T1-weighted images were obtained in the coronal, oblique coronal and oblique axial planes, and T1-and T2-weighted images were obtained in the axial plane. Labral lesions were graded according to the Czerny classification and evaluated on the basis of presence or absence of a tear and location (anteroinferior, anterosuperior, superior, posterosuperior, posteroinferior). The findings were then correlated with the arthroscopic findings. RESULTS: After direct and indirect MR arthography, the findings-based on the Czerny classification -were as follows : stage IA:3; IB:1; IIA:8; IIB:1; IIIA:4; IIIB:0. MR arthrography also showed that seven cases were located in the anterosuperior portion of the labrum, seven in the superior portion, and three in the posteroinferior portion. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MR arthrography for diagnosis of the labral tear was 92%, 75%, 92%, 75 %, and 88 %, respectively. CONCLUSION: In this preliminary study, MR arthrography appears to be a promising imaging modality for accurate diagnosis and useful for screening patients with chronic hip pain.

Subchondral Cysts of the Humeral Head: MR Imaging Findings

PURPOSE: To evaluate the findings of subchondral cyst of the humeral head, as seen on shoulder MRarthrography MATERIALS AND METHODS: Sixty-three patients( M:F=62:1 ; mean age 23 years) who underwent shoulder MRarthrography between September 1996 and May 1998 were retrospectively reviewed. No patient had a history of eithershoulder dislocation or certain diseases known to be commonl accompanied by subchondral cysts. All MR images wereobtained using a 1.5 Tesla unit after intraarticular injection of 20ml of diluted contrast material. T1 andT2-weighted axial, oblique coronal, and oblique sagittal images were analysed for the presence, location, number,shape, size, and connection to the joint cavity of subchondral cysts. RESULTS: We identified 58 subchondral cystsin 43(71.7%) of 63 cases. All were located in the posterolateral portion of the humeral head, and on the physealline. Twenty-eight patients(65.1%) had one cyst, and 15(34.9%) had two. Thirty-four cysts(58.6%) were round orovoid in shape and, 2-8mm in diameter(average, 3.9mm) ; 24(41.4%) were lobulated and 3-10mm in diameter(average5.3mm). Fifty-three cysts(91.4%) were connected to the joint cavity. CONCLUSIONS: In symptomatic patients, the incidence of subchondral cyst of the humeral head was 71.7%. All were located in the posterolateral portion, andon the physeal line. Most subchondral cysts were connected with the joint cavity.

MIR Arthrography of the Labral-Capular-Ligamentous Complex : Normal Variations and Pitfalls / 대한정형외과학회잡지

MR arthrography is a useful modality for evaluating the labrocapsular ligamentous complex (LCLC) of the shoulder. This study was performed to describe normal anatomic variations and pitfalls in image interpretation related to evaluation of the LCLC. MR arthrogram of 56 shoulders in 41 asymptomatic young, active, male volunteers were prospectively reviewed to evaluate the labral shapes, capsular insertions and images which may mimic the lesions of glenohumeral instability. The anterior and posterior parts of the labra, respectively, varied in shape: triangular (72%,36%), round (13%,35%), cleaved (8%,1%), notched (2%,0%), flat (5%,24%), and absent (0%,4%). The anterior and posterior capsular insertions, respectively, varied in site: Mosely and Oevergaard type I (82%,62%), type II (13%,36%), and type III (5%2%). A number of pitfalls in image interpretation were discovered. Articular cartilage undercutting the labrum (29%) and middle glenohumoral ligament in proximity to anterior labrum (5%) simulated a labral tear. Joint fluid interposed in the central, superior portion of the sublabral sulci (25%) simulated a SLAP lesion. Synovial fold (38%) in the axillary pouch resembled a loose body. Knowledge of normal variations and pitfalls in MR arthrogram image interpretation of labral-capsular-ligamentous complex will help the orthopedist to accurately detect debilitating derangements associated with the glenohumeral instability.