MRI Diagnostic Accuracy Research Articles

Value of MRI in diagnosis of anteromedial and posterolateral bundle tears in patients undergoing anterior cruciate ligament reconstruction

Objective To analyze the value of MRI in the diagnosis of anteromedial bundle(AMB) and posterolateral bundle (PLB) tears in patients undergoing anterior cruciate ligament (ACL) reconstruction. Methods MRI of 141 knees undergoing ACL reconstruction were retrospectively reviewed with using arthroscopy as golden standard to evaluate diagnostic accuracy of MRI to predict AMB and PLB injury conditions. The interval time between MRI and arthroscopic ACL reconstruction was 4 days to 29 days. The median time was 11 days. The injury patterns of AMB and PLB was observed on MRI and classified into normal type, partial tear and complete tear. Using the arthroscopic findings as the golden standard, MRI diagnostic accuracy of AMB and PLB tears was compared with Chi-square test. Results Thirteen cases(9.2%, 13/141) with isolated bundle injury were identified in the arthroscopic assessments among 141 patients, including 11 cases with isolated AMB injury and 2 cases with isolated PLB injury. Combined AMB and PLB injury were all identified in the remaining 128 knees (90.8%, 128/141). There was statistical difference between the incidence rate of isolated bundle injury and double-bundles injury (χ2=6.532, P=0.011). Partial tear was defined as partially torn or interrupted fiber bundles with remaining normal fiber bundles. Complete tear was defined as the fiber bundles in the expected region of the ligament were completely discontinuous. The diagnostic accuracy of MRI in prediction of AMB injury was better than PLB [85.8% (121/141) versus 72.3% (102/141); χ2=7.737, P=0.005]. There was no statistical difference between the accuracy rate of MRI in diagnosis of partial AMB and PLB tear [77.8% (14/18) versus 50.0% (15/30); χ2=3.630, P=0.057]. There was no statistical difference between the accuracy rate of MRI in diagnosis of complete AMB and PLB tear[87.6% (106/121) versus 84.0% (84/100); χ2=0.589, P=0.443]. There was no statistical difference between the accuracy rate of MRI in diagnosis of partial and complete AMB tear (χ2=1.282, P=0.258). There was statistical difference between the accuracy rate of MRI in diagnosis of partial and complete PLB tear (χ2= 14.690, P=0.001). Conclusions Complete AMB and PLB tear are the common injury patterns among patients undergoing ACL reconstruction, while an isolated AMB or PLB tear is uncommon. MRI is of value in the diagnosis of ACL injury. MRI can accurately diagnose complete AMB tear, complete PLB tear and partial AMB tear, but the diagnostic accuracy of MRI in assessing partial PLB tear needs to be improved. Key words: Anterior cruciate ligament; Wounds and injury; Magnetic resonance imaging

Reporting standards in cardiac MRI, CT, and SPECT diagnostic accuracy studies: analysis of the impact of STARD criteria

Diagnostic accuracy studies determine the clinical value of non-invasive cardiac imaging tests. The 'STAndards for the Reporting of Diagnostic accuracy studies' (STARD) were published in 2003 to improve the quality of study reporting. We aimed to assess the reporting quality of cardiac computed tomography (CCT), single positron emission computed tomography (SPECT), and cardiac magnetic resonance (CMR) diagnostic accuracy studies; to evaluate the impact of STARD; and to investigate the relationships between reporting quality, journal impact factor, and study citation index. We randomly generated six groups of 50 diagnostic accuracy studies: 'CMR 1995-2002', 'CMR 2004-11', 'CCT 1995-2002', 'CCT 2004-11', 'SPECT 1995-2002', and 'SPECT 2004-11'. The 300 studies were double-read by two blinded reviewers and reporting quality determined by % adherence to the 25 STARD criteria. Reporting quality increased from 65.3% before STARD to 74.1% after (P = 0.003) in CMR studies and from 61.6 to 79.0% (P < 0.001) in CCT studies. SPECT studies showed no significant change: 71.9% before and 71.5% after STARD (P = 0.92). Journals advising authors to refer to STARD had significantly higher impact factors than those that did not (P = 0.03), and journals with above-median impact factors published studies of significantly higher reporting quality (P < 0.001). Since STARD, citation index has not significantly increased (P = 0.14), but, after adjustment for impact factor, reporting quality continues to increase by ∼1.5% each year. Reporting standards for diagnostic accuracy studies of non-invasive cardiac imaging are at most satisfactory and have improved since the introduction of STARD. Adherence to STARD should be mandatory for authors of diagnostic accuracy studies.

Quality of reporting in cardiac MRI, CT and SPECT diagnostic accuracy studies: Analysis of the impact of STARD criteria

Methods This paper reports on the reporting quality of cardiac computed tomography (CCT), single positron emission computed tomography (SPECT), and cardiac magnetic resonance (CMR) diagnostic accuracy studies in randomly selected groups of 50: ‘CMR 1995-2002’, ‘CMR 20042011’, ‘CCT f 1995-2002’, and ‘CCT 2004-2011’, ‘SPECT 1995-2002’, ‘SPECT 2004-2011’. These 300 studies were read against the 25 STARD criteria (7500 items assessed) and their % adherence determined. Simple and multivariable linear regression models were developed.

MRI signal changes in completely healed meniscus confirmed by second-look arthroscopy after meniscal repair with bioabsorbable arrows

This study evaluated the MRI signal characteristics and MRI diagnostic accuracy in identifying completely healed menisci repaired with bioabsorbable arrows. A total of 34 patients (38 menisci), with a mean age of 26.0 years, underwent arthroscopic meniscal repair with bioabsorbable arrows and concomitant anterior cruciate ligament (ACL) reconstruction. Of the 34 patients, 27 were male and 7 were female. Of the 38 menisci, 27 were medial and 11 were lateral. Second-look arthroscopy was performed for each patient while taking out the hardware for ACL reconstruction of the tibial side to evaluate the healing status of the repaired menisci. Postoperative MRI was done 2 days before or after second-look arthroscopy. Sagittal T1, T2 and PD images and coronal T2 and PD images were used as the main diagnostic serials. Second-look arthroscopy showed that surfaces of the repaired sites of all 38 menici were almost smooth. In all 38 cases the tail ends of meniscus arrows disappeared and in four patients new overlying injury of compartmental cartilage at the repaired side was detected. MRI results revealed that different serials had different diagnostic accuracy. Sagittal: T1 28.9%, PD 34.2%, T2 60.5%. Coronal: PD 36.8%, T2 65.8%. The double sides Grade 3 signal had a higher proportion in saggital T1 and PD serials, 47.4 and 39.5%, respectively, while lower in sagittal and coronal T2 serials, both 5.3%. MRI diagnostic accuracy was correlated positively with the follow-up time (P < 0.05). MRI has its limitation in evaluating the status of menisci repaired with bioabsorbable arrows, especially for PD and T1 serials. T2 serials have higher diagnostic accuracy than other serials. MRI diagnostic accuracy can be improved by prolonging follow-up time and might be improved by further classifying Grade 3 signal in terms of signal intensity and the shape of the signal margin.

Results of a prospective multicenter study for evaluation of the diagnostic quality of an open whole-body low-field MRI unit.: A comparison with high-field MRI measured by the applicable gold standard

Objective: To evaluate the diagnostic quality of an open whole-body low-field MRI scanner compared to high-field scanners. Materials and methods: Over a period of 3 months, 401 patients with diseases of the kidney ( n=78), the shoulder ( n=122), the spine ( n=105) and the cerebrum ( n=96) were prospectively evaluated in four participating centers. They all underwent clinical evaluation, low-field and high-field MRI examination and surgical or follow-up confirmation of diagnosis. Clinical, histopathologic, high-field and low-field MRI diagnoses were recorded in standardized questionnaires that were centrally evaluated. Statistical evaluation comprised two parts: ROC analysis assessed accuracy of MRI and clinical diagnoses; furthermore rates of concordance of high- and low-field MRI diagnosis were calculated. Results: We found no statistically relevant difference in high-field MRI diagnosis compared to low-field MRI diagnostic accuracy measured by clinical or surgical gold standard in three of the four regions examined; in cerebral examinations there was a small yet significant advantage for the high-field systems ( P=0.01). Conclusion: We conclude that the open low-field scanner we evaluated using clinical and surgical gold standard as reference is able to achieve comparable diagnostic accuracy compared to high-field scanners at lower costs and greater patient comfort. Limitations due to field strength (signal-to-noise ratio, resolution, scan time) seem to be relevant only in a very small number of cases that warrant high-field examination.

Role of magnetic resonance imaging in hypothalamic-pituitary disorders.

Improvement of MRI diagnostic accuracy in the study of the hypothalamic-pituitary region provides precise anatomic details. In pituitary dwarfism, MRI reveals severe sella/pituitary gland and stalk hypoplasia with or without posterior pituitary ectopia, and empty sella, and this more frequently in patients with multiple pituitary hormone deficiency. Two main hypotheses have been proposed to explain these findings: traumatic stalk transection during breech delivery, and abnormal embryonic development of the pituitary gland. The association between neuroradiological findings and type/severity of endocrine alteration has not yet been clarified. In diabetes insipidus, MRI findings are normal picture, posterior lobe not visible, and thickened stalk (as expression of preclinical/initial histocytosis). Patients with central precocious puberty or hypogonadotropic hypogonadism rarely show morphologic abnormalities (hamartoma of the tuber cinereum, partially empty sella). So far, MRI permits one to identify morphologic pictures in diseases previously considered 'idiopathic'.