ABSTRACT
Background: This study aimed to develop a classification system for lumbar disc degeneration using routine magnetic resonance images (MRIs) that is easily applicable and unaffected by existing classifications' limitations, and to compare its reliability, reproducibility, and discriminative power to the widely used Pfirrmann classification. Methods: Five features were graded. This new classification system has eight grades, with at least one of these five features altering each grade. The T2-weighted sagittal images were acquired using a rapid spin-echo sequence with a repetition time of 2680 to 4900 milliseconds, an echo time of 100 to 109 milliseconds, and an echo train length of 17. Slice thick was 4 mm and the display field of view was 32 × 32 cm. The new classification system used five features: signal intensity, disc height, disc boundary regularity, and nucleus annulus separation. Increased signal intensity, decreased height, decreased regularity, and decreased nucleus-annulus separation indicated degeneration. Four raters classified 400 discs from 80 patients using the Pfirrmann and Novel systems. Statistical analyses were conducted to investigate reliability and correlation. Results: The overall ICC and kappa values were found to be higher in the novel classification. (0.988 indicating excellent agreement for ICC and 0.76/0.94 indicating good-very good agreement for kappa). The Kendall tau c value, which shows the correlation between the two classifications and indicates the validity of the new classification, was 0.872, which is very strong. Through the use of cross-tabulations, the discriminatory power of the two newly added classification criteria was determined. Conclusions: This study demonstrates the intra-rater and inter-rater reliability of an easy-to-use, discriminative novel morphometric MRI based classification system for lumbar disc degeneration. The differentiation of grades based on five distinct criteria may generate novel hypotheses regarding treatment selection and response monitoring, as well as new insights into the study of disc degeneration.
ABSTRACT
Resumen El origen geográfico de la semilla ejerce un control genético sobre los caracteres de comportamiento de las plantas por lo cual su selección es una herramienta útil para lograr la máxima adaptación de la especie al medio. En este sentido, la caracterización de materiales de diferentes procedencias brinda información para la elección de las fuentes de semilla utilizables en programas de mejora, así como en proyectos de forestación y/o repoblación. El presente trabajo tuvo como objetivo establecer el efecto de la procedencia sobre las variables morfológicas que constituyen parámetros de calidad en plantines de Prosopis alba provenientes de tres áreas geográficas. Se midieron variables morfológicas de las plantas hasta los 150 días posteriores a la siembra. El efecto de la procedencia resultó significativo para la mayoría de las variables medidas: altura de las plantas y diámetro a la altura del cuello (al menos durante los primeros 3 meses de viverización), volumen de raíz, peso foliar específico y área foliar específica. Así mismo algunos de los índices y cocientes morfológicos considerados como variables para determinar la calidad de plantas resultan afectados por el origen geográfico del material: relación longitud parte aérea/parte radical, coeficiente de esbeltez e índice de esbeltez. Los resultados permiten afirmar que en P. alba la procedencia influye sobre la morfología de las plantas y determina la existencia de dos grupos diferentes: por un lado, las procedencias santiagueña y chaqueña y, por otro, la procedencia Salta Norte.
Abstract Seed provenance has a genetic control over the behavioral characteristics of plants, whereby selection is an useful tool to achieve the maximum adaptation of the species to the environment. In this sense, different provenance materials characterization provides information for choosing seed sources used in breeding programs, as well as afforestation and/or reforestation projects. The aim of this work was established provenance´s effect on morphological variables that constitute quality parameters in Prosopis alba seedlings from three geographic areas. Morphological plants´ variables were measured up to 150 days after planting. Provenance effect was significant for most of measured variables: plant´s height, neck diameter (at least during the first 3 months of nursery), root volume, specific leaf weight and specific leaf area. Likewise, some of the morphological indices and quotients considered variables to determine plants´ quality are affected by material´s geographical origin: shoot length/ root length proportion, slenderness coefficient and index. Results allow affirming P. alba´s provenance influences plants´ morphology determining the existence of two different groups: on one hand Santiago del Estero and Chaco provenances, and on the other, Salta Norte origin. Rev. Biol. Trop. 66(2): 593-604. Epub 2018 June 01.
