Meniscal tears: comparison of the conventional spin-echo and fast spin-echo techniques through image processing.

BACKGROUND: Conventional spin-echo (PD-CSE) and fast spin-echo (PD-FSE) techniques are frequently used to detect meniscal tears. However, the time delay for imaging with PD-CSE has resulted in its replacement with faster techniques, such as proton density fast spin-echo (PD-FSE), which has become a frequent tool at most diagnostic centres.Qualitative analysis shows that the PD-CSE technique is more sensitive, but other authors have not found significant differences between the aforementioned techniques. Therefore, we performed a quantitative analysis in this study that aims to measure differences in the quality of the images obtained with both techniques. METHODS: We compared the PD-CSE and PD-FSE techniques by quantitatively analysing the obtained proton density images: the area shown, as well as the brightness and lesion contrast of the obtained image.A set of 100 images from 50 patients thought to contain meniscal tears of the knee were selected. These 100 images were obtained from all individuals using both the PD-CSE and PD-FSE techniques. The images were processed using software developed in Delphi. In addition to these quantifications, three physicians, who are specialists in radiology and capable of analysing magnetic resonance (MR) images of the musculoskeletal system, qualitatively analysed the diagnostic sensitivity of both techniques. RESULTS: On average, samples obtained via the PD-CSE technique contained 22% more pixels in the lesion area. The contrast differed by 28%, and the brightness differed by 31%. The two techniques were correlated using Student's t-test, which showed a statistically significant difference. The specialists detected meniscal tears in 30 of the images obtained via the PD-CSE technique, while only 72% of these cases were detected via the PD-FSE technique. CONCLUSIONS: The PD-CSE technique was shown to be superior to PD-FSE for all of the evaluated properties, making its selection preferable.

Calculating anterior glenoid bone loss using the Bernageau profile view.

OBJECTIVE: To determine if it is possible to measure glenoid bone loss by using the Bernageau view and to compare it to a 3D CT scan. MATERIALS AND METHODS: Fifty healthy subjects with a mean age of 34 ± 8 years old and 31 (62 %) male were submitted to the Bernageau view X-ray of both shoulders. Three blinded evaluators measured the distance between the posterior and anterior glenoid rim. Ten patients with multiple episodes of unilateral traumatic anterior shoulder dislocation with a mean age of 34 ± 9.1 years old and 90 % male were submitted to the same X-ray technique to determine the percentage of glenoid bone loss. They were also submitted to a bilateral 3D CT scan to be compared to the radiographs. RESULTS: In the 50 asymptomatic subjects, the AP distance was 24.48 mm ± 3.32 mm in the left shoulder and 24.82 mm ± 3.16 mm in the right shoulder. Comparing the X-ray study and the 3D CT scan of the ten patients with multiple episodes, there was no significant statistical difference of the AP normal distance in both methods (p = 0.646), the AP erosion distance (p = 0.386), as well as the percentage of bone loss (p = 0.513). Moreover, the differences between the percentages of bone loss in the X-ray, compared with the 3D CT scan were, on average 2.28 % (range 0 to 6.05 %). CONCLUSIONS: The Bernageau radiographic view is an accurate and reproducible technique for measuring the presence of glenoid erosion, with similar results when compared to the 3D CT scan.