BMC Medical Imaging最新文献

Background: The cervix undergoes morphological and structural changes during pregnancy in preparation for delivery. Assessing the progression of these changes using transvaginal ultrasound (TVUS) is crucial for preterm birth prediction. However, existing methods such as cervical length have limitations in capturing subtle tissue changes. Although tissue analysis using TVUS has been explored to address these limitations, achieving consistent and reproducible results in quantitative analysis remains challenging due to high inter-observer variability and a lack of standardized region of interest (ROI) definitions. This study proposes an oriented cervical canal region (O-CCR) framework that identifies regions containing ultrasound features while preserving anatomical spatial information.

Methods: We utilized 1436 TVUS images for training, validation, and testing, with 189 additional images from a different hospital for external validation. CCR was defined to include the cervical canal and its surrounding region after aligning the IO and EO parallel to ensure anatomical consistency in the cervix. To validate the effectiveness of O-CCR in handling various orientations, we applied five oriented object detection models (Oriented R-CNN, ReDet, S²A-Net, R³Det, and Oriented RepPoints) and evaluated their CCR localization performance.

Results: We compared the performance of five models implemented within O-CCR framework. Among them, Oriented RepPoints achieved the highest average precision (AP) of 0.981 at the intersection over union (IoU) threshold of 0.5, compared to Oriented R-CNN (0.968), S²A-Net (0.962), ReDet (0.964), and R³Det (0.980) on the test dataset. Notably, Oriented RepPoints demonstrated superior performance even at higher thresholds of 0.6 (0.931) and 0.7 (0.743) and the lowest average orientation error (AOE) of 9.1980 in CCR localization.

Conclusion: The proposed O-CCR framework exhibited reliable performance in CCR localization regardless of varying orientations and morphological configurations, while providing standardized regions that preserve the anatomical spatial information of the cervix. The consistent CCR could be applied to quantitative analysis of cervical tissue properties in future research. Ultimately, this approach could support the development of automated cervical change assessment for prenatal care.

Background: Prostate Cancer (PCa) is a heterogeneous disease, where hypoxia and cribriform growth have been established as adverse prognostic features. Hypoxia refers to a condition of limited oxygen concentration within the tumor microenvironment, associated with enhanced tumor aggressiveness, resistance to therapy, and poor clinical outcome. Likewise, cribriform growth has also been related to poor prognosis, though the biologic basis remains unclear. Recent pathological studies suggest that there is an association between cribriform growth and tumor hypoxia, but evidence from PCa patient studies are scarce. To fill this knowledge gap, this study aims to investigate the association between hypoxia measured by MR imaging and cribriform growth identified in whole-mount histological specimens.

Methods: A retrospective cohort of 291 patients with biopsy-confirmed PCa who underwent radical prostatectomy and pre-operative MRI was analyzed. Tumors were graded according to the 2019 ISUP classification, and cribriform growth presence and length were assessed on whole-mount histology. The oxygen consumption and supply based model using apparent diffusion coefficient and fractional blood volume was applied to estimate hypoxia level (HL) and hypoxia fraction (HF_DWI). Differences in HL and HF_DWI across Gleason patterns and between cribriform growth-positive and -negative tumors were assessed. Furthermore, a linear regression model was used to evaluate the association between cribriform growth and hypoxia after adjusting for confounders.

Results: Cribriform growth-positive tumors exhibited significantly higher HF_DWI values compared to cribriform growth-negative tumors (p < 0.001). Within individual cancer Grade Groups (GG), cribriform growth length was significantly associated with increased HF_DWI in pGG 3 tumors. HL_median values were highest in Gleason Pattern 3 (GP3) regions and lowest in cribriform growth (GP4Crib+) regions, with significant differences observed between GP3 vs. non-cribriform growth GP4 regions (p < 0.001) and GP3 vs. GP4Crib+ (p < 0.001), consistent with more hypoxia in GP4Crib+. Multivariable regression confirmed cribriform growth presence as an independent predictor of increased hypoxia fraction, even after adjusting for tumor volume and GG.

Conclusions: This study shows an association between cribriform growth and tumor hypoxia using an MRI-based biomarker. These findings provide further biological insights into the aggressive nature of cribriform growth architecture and highlight the potential clinical utility of non-invasive hypoxia quantification for risk stratification in prostate cancer management.

Clinical trial number: Not applicable.