Middle patellar tendon to posterior cruciate ligament (PT-PCL) and normalized PT-PCL : new magnetic resonance indices for tibial tubercle position in patients with patellar instability

BACKGROUND: To demonstrate whether the distance between the middle point of the patellar tendon and posterior cruciate ligament (PT-PCL) calculated on a single axial MR image could be an alternative measure to tibial tubercle-PCL (TT-PCL) distance for TT lateralization without the need of imaging processing. To show that normalization of PT-PCL (nPT-PCL) against the maximum diameter of the tibial plateau may help to identify patients with patellar instability (PI). METHODS: MR scans of 30 patients (13 females, age 32\u202f\ub1\u202f13\u202fyears) with known PI and 60 patients (31 females, age 39\u202f\ub1\u202f19\u202fyears) with no history of PI were reviewed. Two operators calculated TT-PCL, and PT-PCL nPT-PCL. Intraclass correlation coefficient, Student's t-test, Receiver Operator Characteristic curves, Spearman's Rho and McNemar's test were used. RESULTS: Interobserver reproducibility was 0.894 for PT-PCL for TT-PCL (95% CI\u202f=\u202f0.839-0.930) and 0.866 for TT-PCL (95% CI\u202f=\u202f0.796-0.912). The PT-PCL was 23.5\u202f\ub1\u202f3.8\u202fmm in patients and 20.0\u202f\ub1\u202f2.7\u202fmm in controls (P\u202f<\u202f0.001). The TT-PCL was 22.9\u202f\ub1\u202f3.9\u202fmm in patients and 20.5\u202f\ub1\u202f2.7\u202fmm in controls (P\u202f=\u202f0.002). Correlation between the PT-PCL and TT-PCL was R\u202f=\u202f0.838, P\u202f<\u202f0.001. The PT-PCL had 66.6% (95% CI\u202f=\u202f0.542-0.790) diagnostic yield. The nPT-PCL was significantly higher in patients (0.302\u202f\ub1\u202f0.03) than controls (0.271\u202f\ub1\u202f0.03; P\u202f<\u202f0.001) with 73.9% (95% CI\u202f=\u202f0.628-0.851) diagnostic yield. CONCLUSION: The PT-PCL correlated with TT-PCL, with 66.6% diagnostic yield. The nPT-PCL may represent an additional index, with 73.9% diagnostic yield

Development and evaluation of a secondary reference panel for BCR-ABL1 quantitation on the International Scale

Molecular monitoring of chronic myeloid leukemia patients using robust BCR-ABL1 tests standardized to the International Scale (IS) is key to proper disease management, especially when treatment cessation is considered. Most laboratories currently utilize a time-consuming sample exchange process with reference laboratories for IS calibration. A World Health Organization (WHO) BCR-ABL1 reference panel was developed (MR1-MR4), but access to the material is limited. In this study, we describe the development of the first cell-based secondary reference panel that’s traceable to and faithfully replicates the WHO panel, with an additional MR4.5 level. The secondary panel was calibrated to IS using digital PCR with ABL1, BCR, and GUSB as reference genes and evaluated by 44 laboratories worldwide. Interestingly, we found that &gt;40% of BCR-ABL1 assays showed signs of inadequate optimization such as poor linearity and suboptimal PCR efficiency. Nonetheless, when optimized sample inputs were used, &gt;60% demonstrated satisfactory IS accuracy, precision and/or MR4.5 sensitivity, and 58% obtained IS conversion factors from the secondary reference concordant with their current ones. Correlation analysis indicated no significant alterations in %BCR-ABL1 results caused by different assay configurations. More assays achieved good precision and/or sensitivity than IS accuracy, indicating the need for better IS calibration mechanisms