Diffusion-Weighted Imaging of Brain Metastasis from Lung Cancer: Correlation of MRI Parameters with the Histologic Type and Gene Mutation Status.

BACKGROUND AND PURPOSE: Development of noninvasive imaging biomarkers indicating the histology and the gene mutation status of brain metastasis from lung cancer is important. We aimed to investigate diffusion-weighted imaging parameters as predictors of the histology and gene mutations of brain metastasis from lung cancer. MATERIALS AND METHODS: DWI data for 74 patients with brain metastasis from lung cancer were retrospectively reviewed. The patients were first grouped according to the primary tumor histology (adenocarcinoma, small-cell lung cancer, squamous cell carcinoma), and those with adenocarcinoma were further divided into epidermal growth factor receptor (EFGR) mutation-positive and wild type groups. Sex; age; number, size, and location of brain metastasis; DWI visual scores; the minimum ADC; and the normalized ADC ratio were compared among groups using χ2 and ANOVA. Multiple logistic regression analysis was performed to determine independent predictors of the EGFR mutation. RESULTS: The minimum ADC was lower in the small-cell lung cancer group than in the other 2 groups, though the difference was not significant. Furthermore, minimum ADC and the normalized ADC ratio were significantly lower in the EGFR mutation-positive group than in the wild type group (P = .021 and .014, respectively). Multivariate analysis revealed that minimum ADC and the normalized ADC ratio were independently associated with the EGFR mutation status (P = .028 and .021, respectively). CONCLUSIONS: Our results suggest that DWI parameters (minimum ADC and normalized ADC ratio) for the solid components of brain metastasis from lung cancer are not correlated with their histology, whereas they can predict the EGFR mutation status in brain metastasis from lung adenocarcinoma.

The relationship of the anterior articular capsule to the adjacent subscapularis: An anatomic and histological study.

INTRODUCTION: The purpose of this study was to delineate the anatomic relationship between the anterior articular capsule and the adjacent subscapularis by measuring the dimensions of the anterior articular capsule attachment and the subscapularis footprint on the humerus, as well as investigating the interface between the two structures. MATERIALS AND METHODS: Three shoulder specimens underwent histological analysis; for histological analysis, cross-sections through the subscapularis-capsule complex were harvested at the tendinous and muscular insertion sites. The dimensions of the anterior articular capsule attachment and the subscapularis footprint (including the tendinous and muscular insertions) were measured in thirteen cadaveric shoulder specimens. RESULTS: Histologically, the articular capsule has thin and loosely arranged collagen fibers with many interspersing fibroblast nuclei, whereas the outer layer of the articular capsule blends into a layer of more loosely spaced and less organized collagen fibers. This interface between the subscapularis and the underlying articular capsule is filled with more loosely spaced and less organized collagen fibers. The macroscopic evaluation showed that the minimum articular capsule width (4.2mm, SD 2.2mm) was located at its initiation 4.9mm (SD, 2.1mm) inferior to the superior margin of the subscapularis; the corresponding subscapularis footprint width measured 10.1mm (SD, 4.9mm). The maximum articular capsule width was11.1 mm (SD, 3.7mm) and was located 5mm distal to the inferior margin of the tendinous footprint. The maximum subscapularis footprint width was 15.8mm (SD, 2.9mm); the corresponding articular capsule attachment measured 5.2mm (SD, 1.8mm). CONCLUSIONS: Our results suggest that the anterior articular capsule attachment of the glenohumeral joint complements the footprint of the subscapularis and occupies a larger area of the lesser tubercle and metaphysis of the humerus than previously documented. The histological study confirms the presence of a demarcation between the subscapularis and articular capsule, specifically more significant at the region medial to the tendon insertion and at the muscular insertion of the subscapularis.