MRI Staging in an Evolving Management Paradigm for Rectal Cancer, From the AJR Special Series on Cancer Staging.

The treatment of rectal cancer centers around the distinct but related goals of management of distant metastases and management of local disease. Optimal local management requires attention to the primary tumor and its anatomic relationship to surrounding pelvic structures, with the goal of minimizing local recurrence (LR). High-resolution MRI is ideally suited for this purpose; application of MRI-based criteria in conjunction with optimized surgical and pathologic techniques has successfully reduced LR rates. This success has led to a shift away from using the TNM-based National Comprehensive Cancer Network (NCCN) guidelines as the sole determinant of whether a patient receives neoadjuvant chemoradiation. The new model uses a hybrid approach for assigning risk categories that combines elements of the TNM staging system with MRI-based anatomic features. These risk categories incorporate tumor proximity to the circumferential resection margin, T category, distance to the anal verge, and presence of extramural venous invasion to classify rectal tumors as low, intermediate, or high risk. This approach has been validated by accumulated data from numerous multiinstitutional studies. This article illustrates key anatomic concepts, depicts common interpretive errors and pitfalls, and discusses ongoing limitations; these insights should guide radiologists in optimal rectal MRI interpretation.

Development of novel gastroretentive salbutamol sulfate-loaded sodium alginate-pectin bubble beads prepared by co-axial needle air-injection method and in vivo clinical evaluation by ultrasound studies.

In the present study, the salbutamol sulfate-loaded sodium alginate-pectin (SS-loaded SA-PEC) bubble beads have been optimized and evaluated for drug loading, in vitro drug release, in vivo floating behavior in the stomach, etc. Nine batches (F1-F9) of bubble beads with different SA and PEC contents were prepared by novel co-axial needle air-injection method and related to their percent drug loading efficiency (%DLE) and percent drug release at 4 h (%R4h) as response factors. The multivariate analysis has shown the effect of SA/PEC ratio, total polymer content, as well as their interaction on %DLE and %R4h. In the quantitative modeling, the satisfactory adjustment of the linear models (along with interaction terms) with the experimental data for both %DLE and %R4h has confirmed the findings of the multivariate analysis. The optimized SS-loaded SA-PEC bubble beads based on 2D (contours), 3D, desirability, and overlay plots has exhibited %DLE of 87.35 ±â€¯2.48% (n = 3 and error = 2.94%) and %R4h of 85.79 ±â€¯2.98% (n = 3 and error = 0.25%). The in vitro drug release studies have shown almost complete (≥85%) SS release from all the batches within 4-6 h in simulated gastric fluid (SGF) pH 1.2. The in vivo clinical findings by ultrasound studies have shown excellent floatation (>6 h) behavior of bubble beads in the upper gastrointestinal tract (GIT) and efficient stomach-specific gastroretention.