Bogveradze Nino, Maas Monique, El Khababi Najim, Schurink Niels W, Lahaye Max J, Bakers Frans Ch, Tanis Pieter J, Kusters Miranda, Beets Geerard L, Beets-Tan Regina Gh, Lambregts Doenja Mj
Department of Radiology, 1228The Netherlands Cancer Institute, Amsterdam, The Netherlands.
GROW School for Oncology & Developmental Biology, 5211University of Maastricht, Maastricht, The Netherlands.
Acta Radiol. 2023 Feb;64(2):467-472. doi: 10.1177/02841851221091209. Epub 2022 Apr 11.
The sigmoid take-off (STO) is a recently established landmark to discern rectal from sigmoid cancer on imaging. STO-assessment can be challenging on magnetic resonance imaging (MRI) due to varying axial planes.
To establish the benefit of using computed tomography (CT; with consistent axial planes), in addition to MRI, to anatomically classify rectal versus sigmoid cancer using the STO.
A senior and junior radiologist retrospectively classified 40 patients with rectal/rectosigmoid cancers using the STO, first on MRI-only (sagittal and oblique-axial views) and then using a combination of MRI and axial CT. Tumors were classified as rectal/rectosigmoid/sigmoid (according to published STO definitions) and then dichotomized into rectal versus sigmoid. Diagnostic confidence was documented using a 5-point scale.
Adding CT resulted in a change in anatomical tumor classification in 4/40 cases (10%) for the junior reader and in 6/40 cases (15%) for the senior reader. Diagnostic confidence increased significantly after adding CT for the junior reader (mean score 3.85 vs. 4.27; < 0.001); confidence of the senior reader was not affected (4.28 vs. 4.25; = 0.80). Inter-observer agreement was similarly good for MRI only (κ=0.77) and MRI + CT (κ=0.76). Readers reached consensus on the classification of rectal versus sigmoid cancer in 78%-85% of cases.
Availability of a consistent axial imaging plane - in the case of this study provided by CT - in addition to a standard MRI protocol with sagittal and oblique-axial imaging views can be helpful to more confidently localize tumors using the STO as a landmark, especially for more junior readers.
乙状结肠起始部（STO）是最近确定的一个影像学标志，用于在成像时区分直肠癌和乙状结肠癌。由于轴向平面不同，在磁共振成像（MRI）上进行STO评估可能具有挑战性。
除MRI外，确定使用计算机断层扫描（CT；具有一致的轴向平面）通过STO对直肠癌和乙状结肠癌进行解剖学分类的益处。
一名资深放射科医生和一名初级放射科医生对40例直肠/直肠乙状结肠癌患者进行回顾性研究，首先仅根据MRI（矢状面和斜轴面视图）使用STO进行分类，然后结合MRI和轴向CT进行分类。肿瘤根据已发表的STO定义分为直肠/直肠乙状结肠/乙状结肠，然后再分为直肠癌和乙状结肠癌。使用5分制记录诊断信心。
对于初级读者，添加CT后4/40例（10%）的肿瘤解剖学分类发生了变化；对于资深读者，6/40例（15%）发生了变化。添加CT后，初级读者的诊断信心显著提高（平均评分3.85对4.27；<0.001）；资深读者的信心未受影响（4.28对4.25；=0.80）。仅MRI（κ=0.77）和MRI+CT（κ=0.76）时，观察者间一致性同样良好。读者在78%-85%的病例中就直肠癌和乙状结肠癌的分类达成了共识。
除了具有矢状面和斜轴面成像视图的标准MRI方案外，提供一致的轴向成像平面（本研究中由CT提供）有助于更自信地使用STO作为标志定位肿瘤，尤其是对于经验较少的读者。
