Multidetector Computed Tomography Arthrography Research Articles

Diagnostic Performance of Multi-Detector Computed Tomography Arthrography and 3-Tesla Magnetic Resonance Imaging to Diagnose Experimentally Created Articular Cartilage Lesions in Equine Cadaver Stifles.

The purpose of the study was to determine the diagnostic performance of computed tomographic arthrography (CTA) and 3-Tesla magnetic resonance imaging (MRI) for detecting artificial cartilage lesions in equine femorotibial and femoropatellar joints. A total of 79 cartilage defects were created arthroscopically in 15 cadaver stifles from adult horses in eight different locations. In addition, 68 sites served as negative controls. MRI and CTA (80-160 mL iodinated contrast media at 87.5 mg/mL per joint) studies were obtained and evaluated by a radiologist unaware of the lesion distribution. The stifles were macroscopically evaluated, and lesion surface area, depth, and volume were determined. The sensitivity and specificity of MRI and CTA were calculated and compared between modalities. The sensitivity values of CTA (53%) and MRI (66%) were not significantly different (p = 0.09). However, the specificity of CTA (66%) was significantly greater compared to MRI (52%) (p = 0.04). The mean lesion surface area was 11 mm2 (range: 2-54 mm2). Greater lesion surface area resulted in greater odds of lesion detection with CTA but not with MRI. CTA achieved a similar diagnostic performance compared to high-field MRI in detecting small experimental cartilage lesions. Despite this, CTA showed a higher specificity than MRI, thus making CTA more accurate in diagnosing normal cartilage. Small lesion size was a discriminating factor for lesion detection. In a clinical setting, CTA may be preferred over MRI due to higher availability and easier image acquisition.

Ex vivo comparison of 3 Tesla magnetic resonance imaging and multidetector computed tomography arthrography to identify artificial soft tissue lesions in equine stifles.

OBJECTIVETo determine the diagnostic performance of computed tomographic arthrography (CTA) and 3 Tesla magnetic resonance imaging (MRI) for detecting artificial meniscal, meniscotibial ligament (MTL) lesions and cruciate ligament (CL) lesions in horses.STUDY DESIGNEx vivo controlled laboratory study.ANIMALSNineteen stifles from adult horses.METHODSStablike defects (n = 84) (16 mm long, 10 mm deep) were created in the menisci (n = 35), CLs (n = 24), and MTLs (n = 25) via arthroscopy prior to MRI and CTA (80 mL contrast at 85 mg/mL per joint). Two radiologists, unaware of the lesions, reached a consensus regarding the presence of lesions, based on 2 reviews of each study. Sensitivity and specificity of MRI and CTA were determined using arthroscopy as a reference and compared with McNemar's tests.RESULTSThe sensitivity and specificity of MRI (41% and 86% respectively) and CTA (32% and 90% respectively) did not differ (P = .65). The sensitivity (MRI: 24%‐50%; CTA:19%‐40%) and specificity (MRI: 75%‐92%; CTA 75%‐100%) of imaging modalities did not differ when detecting lesions of the menisci, MTLs, and CLs (P = .1‐1.0). The highest sensitivities were achieved when MTLs were evaluated with MRI (50%) and CLs with both modalities (40%).CONCLUSIONSThe diagnostic performance of CTA was comparable with that of MRI, with a low to moderate sensitivity and high specificity.CLINICAL SIGNIFICANCEComputed tomographic arthrography should be considered as an adjunct to diagnose CL injuries. This is important for equine clinicians, as the CL cannot be visualized adequately using basic imaging techniques preoperatively.

Flat-panel CT arthrography for cartilage defect detection in the ankle joint: first results in vivo.

The purpose of this study was to compare the diagnostic performance of flat-panel computed tomography (FPCT) arthrography for cartilage defect detection in the ankle joint to direct magnetic resonance (MR) arthrography using multidetector computed tomography (MDCT) arthrography as the reference standard. Twenty-seven patients with specific suspicion of articular cartilage lesion underwent ankle arthrography with injection of a mixture of diluted gadolinium and iobitridol and were examined consecutively with the use of FPCT, MDCT, and 1.5T MR imaging. FPCT, MDCT, and MR arthrography examinations were blinded and randomly evaluated by two musculoskeletal radiologists in consensus. In each ankle, eight articular cartilage areas were assessed separately: medial talar surface, medial talar trochlea, lateral talar trochlea, lateral talar surface, tibial malleolus, medial tibial plafond, lateral tibial plafond, and fibular malleolus. Findings at FPCT and MR were compared with MDCT assessments in 216 cartilage areas. For the detection of cartilage defects, FPCT demonstrated a sensitivity of 97%, specificity of 95%, and accuracy of 96%; and MR arthrography showed a sensitivity of 69%, specificity of 94%, and accuracy of 87%. FPCT and MR arthrography presented almost perfect agreement (κ = 0.87) and moderate agreement (κ = 0.60), respectively, with MDCT arthrography. Mean diagnostic confidence was higher for FPCT (2.9/3) than for MR (2.3/3) and MDCT (2.7/3) arthrography. FPCT demonstrated better accuracy than did 1.5T MR arthrography for cartilage defect detection in the ankle joint. Therefore, FPCT should be considered in patients scheduled for dedicated imaging of ankle articular cartilage.

The comparison of direct magnetic resonance arthrography with volumetric interpolated breath-hold examination sequence and multidetector computed tomography arthrography techniques in detection of talar osteochondral lesions

ObjectiveThe aim of this study was to compare additive diagnostic values of magnetic resonance (MR) arthrography with volumetric interpolated breath-hold examination (VIBE) sequence and multidetector computed tomography (MDCT) arthrography for diagnosis and grading of talar osteochondral lesions. MethodsMDCT arthrography and MR arthrography with three dimensional VIBE sequence were performed in 27 patients. Findings of MR arthrography and MDCT arthrography images were compared with arthroscopic findings. Sensitivity, specificity, and accuracy rates were calculated for both MR arthrography and MDCT arthrography imaging findings. ResultsFor grade I osteochondral lesions; sensitivity, specificity and accuracy rates of MR arthrography were 95%, 73%, 90%, respectively; For grade I osteochondral lesions; sensitivity, specificity and accuracy rates of MDCT arthrography were 96%, 79%, 81%. For grade IV osteochondral lesions; sensitivity, specificity and accuracy rates of MDCT arthrography and MR arthrography were 100%. For grade II lesions, the sensitivity, specificity and accuracy rates of the MR arthrography were 80%, 76%, 77%, respectively; for grade III lesions, the sensitivity, specificity and accuracy rates of the MR arthrography were 78%, 68%, 75%. For grade II osteochondral lesions; the sensitivity, specificity and accuracy rates of the MDCT arthrography were 91%, 81%, 86%; for grade III osteochondral lesions; the sensitivity, specificity and accuracy rates of the MDCT arthrography were 90%, 83%, 89%; For grade II and III osteochondral lesions, MDCT arthrography had higher sensitivity, specificity and accuracy rates than MR arthrography. MDCT arthrography had higher diagnostic performance than MR arthrography for detection of grade II and III lesions (p = 0.041 and p = 0.038, respectively). ConclusionMDCT arthrography appears to be more reliable than MR arthrography with three dimensional VIBE sequence for accurate detection and grading of osteochondral lesions. Level of evidenceLevel III, Diagnostic Study.

Optimizing radiation dose parameters in MDCT arthrography of the shoulder: illustration of basic concepts in a cadaveric study.

To determine in a cadaveric study the lowest achievable radiation dose and optimal tube potential generating diagnostic image quality in multidetector computed tomography (MDCT) arthrography of the shoulder. Six shoulders from three human cadavers were scanned using a 256-MDCT system after intra-articular injection of diluted iodinated contrast material. Using six decreasing radiation dose levels (CTDIvol: 20, 15, 10, 8, 6, and 4mGy) and for each dose level, four decreasing tube potentials (140, 120, 100, and 80kVp), image noise and contrast-to-noise ratio (CNR) were measured. Two independent and blinded observers assessed the overall diagnostic image quality, subjective amount of noise, and severity of artifacts according to a four-point scale. Influence of those MDCT data acquisition parameters on objective and subjective image quality was analyzed using the Kruskal-Wallis and Wilcoxon signed-rank tests, and pairwise comparisons were performed. Multidetector CT protocols with radiation doses of 15mGy or higher, combined with tube potentials of 100kVp or higher, were equivalent in CNR to the reference 20mGy-140kVp protocol (all p ≥ 0.054). Above a CTDIvol of 10mGy and a tube potential of 120kVp, all protocols generated diagnostic image quality and subjective noise equivalent to the 20mGy-140kVp protocol (all p ≥ 0.22). Diagnostic image quality in MDCT arthrography of the shoulder can be obtained with a radiation dose of 10mGy at an optimal tube potential of 120kVp, corresponding to a reduction of up to 50% compared with standard-dose protocols, and as high as 500% compared with reported protocols in the literature.

No difference in prevalence of radiographic subspinal impingement of the hip between symptomatic and asymptomatic subjects.

The study determined the prevalence of subspinal impingement (SSI) in symptomatic and asymptomatic individuals, morphologic characteristics in symptomatic patients, and risk factors for SSI. The study cohort consisted of 427 patients (427 hips; median age 33.4years; range 19-50years) with mechanical symptoms who underwent multi-detector computed tomography arthrography (symptomatic patients) and 259 control (asymptomatic) patients who underwent abdominopelvic three-dimensional CT because of a ureter stone or minor trauma. Two orthopaedic surgeons reviewed the images to evaluate the prevalence of SSI and the relationship with morphologic abnormalities. Radiologic parameters were further compared between the SSI and non-SSI groups in symptomatic patients using the Chi-squared test or two-sample t test. Variables with p values <0.10 (sex and age) were included in the multi-variate analysis. Logistic regression analysis was carried out to identify independent risk factors for SSI. The prevalence of SSI in symptomatic and asymptomatic patients was 65/427 (15.2%) and 40/259 (15.4%), respectively (n.s.). Structural bony abnormalities in symptomatic patients were not associated with the presence of SSI (n.s.). Binary logistic regression analysis revealed that youth (odds ratio 0.952, 95% CI 0.922-0.984) was the only significant factor for SSI. SSI had a similar prevalence in symptomatic and asymptomatic patients and was not rare in either group. Therefore, clinical implication of SSI in symptomatic patient should be re-evaluated through further study. Level IV.

MDCT Arthrography of the Shoulder.

High-resolution multidetector computed tomography (MDCT) arthrography of the shoulder can diagnose internal derangement of the glenohumeral joints including abnormalities of the rotator cuff, glenoid labrum, and articular cartilage. Isotropic data sets and postprocessing techniques enable interactive three-dimensional image analysis that is capable of reducing artifacts for metal implants. In this article, we review the indications for MDCT arthrography of the shoulder, highlight techniques and important features of the MDCT acquisition, and review normal and abnormal MDCT arthrography appearances of the glenohumeral joint.

The role of MDCT arthrography in the follow-up of scapholunate stabilisation

The aim of this study was to assess outcomes in a group of patients with scapholunate dissociation treated with stabilisation surgery (Brunelli-Stanley) and to compare arthrography with multidetector computed tomography (MDCT) with conventional radiography, the gold standard in the follow-up of wrist surgery. Twelve patients (13 wrists) underwent surgery for scapholunate dissociation and were followed up with clinical (visual analogue scale, Mayo Wrist Score, Patient-Rated Wrist Evaluation, and Disabilities of the Arm, Shoulder, and Hand) and radiological assessment (conventional radiography and CT arthrography). Conventional radiography was assessed for: the scapholunate gap, scapholunate angle, radiolunate angle, capitate-lunate angle, and carpal height index; the CT arthrography images were also evaluated for: the distance between the dorsal exit hole of the bone tunnel and the proximal scaphoid pole, the thickness and tension of the flexor carpi radialis (FCR) strip, and any signs of joint degeneration. Analysis of the data from conventional radiography and MDCT arthrography demonstrated a significant statistical correlation among the measurements obtained on the radiograms and multiplanar CT reconstructions and the patients' clinical outcome. Our results show that MDCT arthrography has the same value as conventional radiography in the evaluation of standard parameters (scapholunate gap, scapholunate angle, radiolunate angle, capitolunate angle, carpal height index), but in addition provides an accurate delineation of the FCR tendon graft, allowing differentiation of its thickness, direction and degree of tension.

Evaluation of Rotator Cuff Tendon Tears: Comparison of Multidetector CT Arthrography and 1.5-T MR Arthrography

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. 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. 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. Data suggest that CT and MR arthrography have similar diagnostic performance for the evaluation of rotator cuff tendon tears.

Flat-Panel CT Arthrography

To show the feasibility of flat-panel computed tomography (FPCT) arthrography and quantitatively and qualitatively compare different FPCT protocols with standard multidetector computed tomography (MDCT). First, a phantom simulating joint space with increasing iodine concentrations was scanned using a standard MDCT and 3 different FPCT protocols. Quantitative analyses were performed by measuring CT numbers of iodine dilutions, radiation dose, and image noise as well as signal-to-noise ratio and contrast-to-noise ratio. Second, FPCT arthrographies of 4 animal joint specimens were performed and analyzed qualitatively by 2 independent readers who evaluated image artifacts, image noise, overall image quality and anatomic depiction of bone, cartilage, and soft tissue. Kappa values were calculated for inter-reader agreement. Pearson's correlation coefficient (r) and Wilcoxon signed-ranks test with Bonferroni corrections for multiple comparisons were used to compare MDCT and FPCT. In phantoms, all CT scans showed a linear correlation between increasing iodine concentrations and mean HU values of contrast media and radiation dose, respectively (r = 0.98-0.99, P < 0.01). Dose-length product remained constant for MDCT scans. Signal-to-noise ratio for phantom water linearly decreased in all FPCT scans with increasing iodine concentrations. Contrast-to-noise ratio curves showed reduced slope at iodine concentrations higher than 75 mg/mL. FPCT arthrography after intra-articular administration of 5 to 6 mL of a 25% dilution of iopromide (Ultravist 300 mg/mL, Bayer HealthCare, Berlin, Germany) was successfully performed in all 4 animal joint specimens. Kappa values for inter-reader agreement of qualitative image analyses were 0.62 to 0.91. Image and depiction quality of 20-s FPCT scans were similar or superior compared with standard MDCT (P < 0.005). FPCT arthrography is feasible and may allow similar image quality compared with standard MDCT arthrography.

Superior Labral Anteroposterior Tears: Accuracy and Interobserver Reliability of Multidetector CT Arthrography for Diagnosis

To evaluate the accuracy and interobserver reliability of multidetector computed tomographic (CT) arthrography for the diagnosis and classification of superior labral anteroposterior (SLAP) lesions. Institutional review board approval and informed consent were obtained. Retrospective review of images from 161 multidetector CT arthrographic examinations was performed by two radiologists independently for detection and classification of SLAP lesions (type I-X), and sensitivity, specificity, accuracy, and interobserver agreement were evaluated. The SLAP group included 94 patients, and the no-SLAP group included 67 patients with normal labrum. At arthroscopy, a total of 88 SLAP lesions (excluding type I) were found. For detection of SLAP lesions excluding SLAP type I lesions, sensitivity, specificity, and accuracy were 94.3%, 76.7%, and 86.3% for reader 1 and 97%, 72.6%, and 86.3% for reader 2, respectively, and the interobserver agreement was very good (κ = 0.87). The distribution of SLAP lesions was as follows: six type I, 58 type II, one type III, one type IV, 16 type V, one type VI, five type VII, three type VIII, one type IX, one type V and VI, and one type V and VII. Percentages of correct classification of SLAP lesions were variable according to the types, but the overall percentage was noted to be 69.2% for reader 1 and 68.1% for reader 2. The interobserver agreement of classification of SLAP lesions was good (κ = 0.72). Multidetector CT arthrography shows high accuracy and good interobserver reliability for diagnosis of SLAP lesions in spite of its limitations in specific classification.

Multidetector computed tomography arthrography of the knee: diagnostic accuracy and indications

To evaluate the diagnostic accuracy and indications of arthrography with multidetector computed tomography (arthro-MDCT) of the knee, in patients with absolute or relative contraindications to MRI and in patients with periarticular metal implants using diagnostic arthroscopy as the gold standard.

Recurrent Superior Labral Anterior-to-Posterior Tears after Surgery: Detection and Grading with CT Arthrography

To retrospectively evaluate the sensitivity and specificity of multidetector computed tomographic (CT) arthrography for the detection of recurrent superior labral anterior-to-posterior (SLAP) tears in the shoulder of patients who have previously undergone shoulder surgery and are clinically suspected of having a recurrent tear. The hospital ethics board did not require patient approval or informed consent for this retrospective review of case records. Multidetector CT arthrograms of 45 shoulders of 45 patients (35 men, 10 women; mean age, 29 years; age range, 21-38 years) who had undergone conventional arthroscopy within 30 days after the CT arthrographic examination were reviewed. Owing to the referral patterns at the authors' institution, all patients were professional athletes. Volumetric multidetector CT arthrography was performed by using a 16-detector CT scanner after the intraarticular injection of iodinated contrast material. All images were independently reviewed by two experienced musculoskeletal radiologists, with disagreements resolved by a third experienced musculoskeletal radiologist. The sensitivity and specificity of multidetector CT arthrography in the detection of any Snyder type II-IV tear was evaluated by using arthroscopy as the reference standard. The numbers and percentages of tears that were assigned the correct Snyder classification with multidetector CT arthrography were reported. Interobserver agreement regarding the correct Snyder classification with multidetector CT arthrography was determined by using kappa statistics. With multidetector CT arthrography, recurrent SLAP tears were correctly identified in 35 of 37 patients (95% sensitivity), and the absence of these tears was correctly noted in seven of eight patients (88% specificity). Multidetector CT arthrography- and arthroscopy-derived tear grades were in agreement in 30 (81%) of 37 patients with recurrent SLAP tears. Interobserver agreement at multidetector CT arthrography was substantial (kappa = 0.76). In the described highly selected patient population, multidetector CT arthrography was useful for evaluating recurrent SLAP tears.

Effectiveness of multidetector computed tomography arthrography for the diagnosis of shoulder pathology: Comparison with magnetic resonance imaging with arthroscopic correlation

This study evaluated the diagnostic efficacy of computed tomography arthrography (CTA) in the assessment of various shoulder pathologies with arthroscopic correlation. We hypothesized that CTA would be cost-effective and effectively comparable with magnetic resonance arthrography (MRA) for assessing labral detachments and full-thickness rotator cuff tears. A musculoskeletal radiologist interpreted CTAs for 78 patients and MRAs for 70 patients. Each imaging study was evaluated for the presence of bony (Hill-Sachs) or labral (Bankart or superior labrum anteroposterior [SLAP]) lesions, and rotator cuff disorder (full- or partial-thickness tears). All patients subsequently underwent arthroscopic surgery. Detailed arthroscopic findings were reported and compared with CTA and MRA findings. The sensitivity, specificity, kappa coefficients, and the area under the receiver operating characteristic (AUROC) curve were calculated. The sensitivity, specificity, and agreement were comparable in each imaging study for Bankart, SLAP, and Hill-Sachs lesions, and full-thickness rotator cuff tears, but those of CTA were significantly lower than MRA for partial-thickness cuff tears. The AUROC curve for CTA and MRA were not significantly different for any of the pathologies, except partial-thickness cuff tears. Our data suggest that CTA is a cost-effective, useful method in the preoperative evaluation of labral abnormalities, such as Bankart and SLAP lesions. It may also be useful for the detection of full-thickness rotator cuff tears. Level I; Diagnostic study.

MDCT Arthrography or MR Arthrography for Imaging the Wrist Joint?

Imaging of the wrist joint has been radically modified over the last decade, particularly since multidetector computed tomography (MDCT) arthrography and magnetic resonance (MR) arthrography have become widely available. These two modalities allow a confident assessment of ligament tears and potential diagnosis of associated abnormalities of cartilage, bone, and soft tissues. The interosseous scapholunate and lunotriquetral ligaments and the triangular fibrocartilage complex (TFCC) are the most important structures to consider. Precise analysis of their different lesions, including recognition of degenerative tears, is essential for guiding the treatment. After a brief overview of the different injuries of interosseous ligaments and cartilage, this article thoroughly exposes the technical aspects of wrist MDCT arthrography and MR arthrography, reviews their results, and discusses their performances in light of recent literature. Finally, we propose an imaging strategy to decide between MDCT arthrography and MR arthrography depending on the clinical query. Other imaging modalities are not forgotten in this strategy. The evaluation of ligamentous and TFCC pathology must always begin with conventional radiographs. Cineradiography, ultrasound, and standard MRI are also useful in selected cases.

Multidetector computed tomography arthrography of the shoulder: diagnostic accuracy and indications

The presence of subcutaneous implants, such as permanent defibrillators, is an absolute contraindication to the use of magnetic resonance imaging (MRI). Moreover, MRI is unadvisable in subjects with metallic hardware near the area of study, as artifacts generated by such materials distort image quality. To evaluate the diagnostic accuracy and indications of arthrography with multidetector computed tomography arthrography (arthro-MDCT) of the shoulder in patients with absolute or relative contraindications to MRI and in patients with periarticular metal implants using diagnostic arthroscopy as the gold standard. After intraarticular injection of iodixanol and volumetric acquisition, 70 shoulders in 70 patients (30 females, 40 males, age range 32-60 years) were examined with a 16-detector-row CT scanner. The patients had arthralgia but no radiologically detected fractures. They could not be studied by MRI because of absolute contraindications (subcutaneous electronic implants), surgical metal implants, or claustrophobia. In 28 of the 70 patients who had had previous shoulder surgery, the arthro-CT examination was preceded by an MRI on the same day. All examinations were interpreted by two experienced musculoskeletal radiologists. The findings were compared with arthroscopic findings carried out within 28 days of the CT study. In the 42 non-operated patients, the comparison between arthro-MDCT and arthroscopy showed sensitivity and specificity ranging between 87% and 100%. In the 28 operated shoulders, arthro-MDCT had an accuracy of 94% compared with 25% with MRI. Interobserver agreement was almost perfect (kappa=0.95) in the evaluation of all types of lesions, both on MDCT and MRI. When arthro-MDCT was compared with MRI in the postoperative patients by a McNemar test, a significant difference (P<0.05) was found between these two techniques. Arthro-MDCT of the shoulder is a safe technique that provides accurate diagnosis in identifying chondral, fibrocartilaginous, and intraarticular ligamentous lesions in patients who cannot be evaluated by MRI, and in patients after surgery.

Multidetector CT Arthrography of the Wrist Joint: How to Do It

With its exquisite spatial resolution, multidetector computed tomographic (CT) arthrography of the wrist is a valuable tool for the diagnosis and evaluation of a wide spectrum of articular disorders. Traumatic tears of the interosseous ligaments can be classified as complete or incomplete and as partial- or full-thickness tears at multidetector CT arthrography and can also be differentiated from asymptomatic degenerative lesions. In addition, tears of the triangular fibrocartilage complex can be differentiated according to their location. A tailored contrast material injection technique and multiplanar reformation are recommended for optimal assessment of these structures. Multidetector CT arthrography is also remarkably effective in demonstrating cartilage and bone abnormalities, many of which cannot be depicted with other imaging techniques. The chief limitation of multidetector CT arthrography lies in the evaluation of soft-tissue abnormalities, which may benefit from the addition of other imaging techniques such as ultrasonography or magnetic resonance imaging. A basic knowledge of the relevant anatomy, pathophysiologic features, and imaging technique is mandatory for obtaining high-yield diagnostic information concerning the wrist joint. (c) RSNA, 2008.

Multidetector computed tomography arthrography of the knee: Diagnostic accuracy and indications

Purpose To evaluate the diagnostic accuracy and indications of arthrography with multidetector computed tomography (arthro-MDCT) of the knee, in patients with absolute or relative contraindications to MRI and in patients with periarticular metal implants using diagnostic arthroscopy as the gold standard. Materials and methods After intra-articular injection of iodixanol and volumetric acquisition, 68 knees in patients of both sexes (30 females, 38 males, age range 32–60 years) were examined with a 16-detector-row CT scanner. The patients had arthralgia but no radiologically detected fractures. They could not be studied by MRI either because of absolute contraindications (subcutaneous electronic implants), surgical metal implants or claustrophobia. In 37 of 68 patients who had had previous knee surgery, the arthro-CT examination was preceded by an MRI on the same day. All examinations were interpreted by two experienced musculoskeletal radiologists. The findings were compared with arthroscopic findings carried out within 28 days of the CT study. Results In non-operated patients the comparison between arthro-MDCT and arthroscopy showed sensitivity and specificity ranging between 86% and 100%. In the 37 operated knees, arthro-MDCT had an accuracy of 95% compared with 53% of the MRI. Inter-observer agreement was almost perfect ( K = 0.97) in the evaluation of all types lesions, both on MDCT and MRI. When arthro-MDCT was compared with MRI in post-operative patients by a McNemar test, a significant difference ( p < 0.05) was found between these two techniques. Conclusions Arthro-MDCT of the knee is a safe technique that provides accurate diagnosis in identifying chondral, fibrocartilaginous and intra-articular ligamentous lesions, in patients that cannot be evaluated by MRI, and in patients after surgical.

Cartilage Thickness: Factors Influencing Multidetector CT Measurements in a Phantom Study

To prospectively assess in a phantom the reconstruction errors and detection limits of cartilage thickness measurements obtained with multidetector computed tomographic (CT) arthrography, as a function of contrast agent concentration, scanning direction, spatial resolution, joint spacing, and tube current, with known measurements as the reference standard. A phantom with nine chambers was constructed. Each chamber had a nylon cylinder encased by sleeves of aluminum and polycarbonate to simulate trabecular bone, cortical bone, and cartilage. Varying simulated cartilage thicknesses and 10 joint space widths were assessed. On 3 days, the phantom was scanned with and without contrast agent administration and with the chamber axes both perpendicular and parallel to the scanner axis. Images were reconstructed at 1.0- and 0.5-mm intervals. Contrast agent concentration and tube current were varied. The simulated cartilage thickness was determined by using image segmentation. Root mean squared errors and mean residual errors were used to characterize the measurements. The reproducibility of the CT scanner and image segmentation results was determined. Simulated cartilage greater than 1.0 mm in thickness was reconstructed with less than 10% error when either no contrast agent or a low concentration (25%) of contrast agent was used. Error increased as contrast agent concentration increased. Decreasing the simulated joint space width to 0.5 mm caused slight increases in error; however, error increased substantially at joint spaces narrower than 0.5 mm. Errors in measurements derived from anisotropic CT data were greater than errors in measurements derived from isotropic data. Altering the tube current did not substantially affect reconstruction errors. The study revealed lower boundaries and the repeatability of simulated cartilage thickness measurements obtained by using multidetector CT arthrography and yielded data pertinent to choosing the contrast agent concentration, joint space width, scanning direction, and spatial resolution to reduce reconstruction errors.

L’artrografia con TC volumetrica 64 strati nell’instabilità di spalla: la nostra esperienza

This study was performed to assess the diagnostic accuracy of air-contrast 64-slice multidetector computed tomography (MDCT) arthrography in the evaluation of glenohumeral joint instability by comparison with conventional arthroscopy. Fifty patients with a history of shoulder instability underwent MDCT arthrography with thin collimation scans. The raw data were transferred to a workstation and processed using multiplanar reformation (MPR) and volume rendering (VR) algorithms. All patients subsequently underwent conventional arthroscopy. The results of the two techniques were compared and their sensitivity and specificity calculated. We diagnosed eight anterosuperior labrum lesions (group 1), 32 anteroinferior labrum lesions (group 2) and two posterior labrum lesions (group 3). Overall sensitivity and specificity (groups 1, 2, 3) were 88% and 100%, respectively. In group 1, sensitivity was only 66% (four false negatives), whereas in groups 2 and 3, it was 94% (two false negatives) and 100%, respectively. The labrum lesions were also found to be associated, with 100% sensitivity and specificity, with 20 lax capsules, 17 Hill-Sachs lesions, five Bankart lesions, two Perthes lesions and three complete rotator-cuff tears. Air-contrast MDCT arthrography is fast, reproducible, well tolerated and very accurate in the evaluation of lesions causing shoulder instability.