1 Department of Radiology, University of Chicago, 5841 S Maryland Ave, Chicago, IL 60637.
2 Department of Radiology, Bezmialem Vakif University, Istanbul, Turkey.
AJR Am J Roentgenol. 2019 Jan;212(1):124-129. doi: 10.2214/AJR.18.19742. Epub 2018 Nov 7.
This study investigates the multiparametric MRI (mpMRI) characteristics and pathologic outcome of wedge-shaped lesions observed on T2-weighted images.
Seventy-six patients with histologically confirmed prostate cancer underwent preoperative 3-T MRI before undergoing radical prostatectomy. Two radiologists worked in consensus to mark wedge-shaped regions of hypointensity on T2-weighted images and assess their appearance on apparent diffusion coefficient (ADC) maps (to determine the degree of hypointensity) and dynamic contrast-enhanced (DCE) MRI (DCE-MRI) (to assess whether they showed early enhancement). The pathologic outcome of wedge-shaped lesions was assessed by matching MR images with whole-mount histologic specimens retrospectively. The difference in quantitative ADC values between malignant and benign wedge-shaped lesions was assessed using a t test.
Thirty-five wedge-shaped regions were identified, 12 (34%) of which were found be malignant. Most malignant wedge-shaped regions were highly hypointense (10/12; 83%) on ADC maps and showed early enhancement on DCE-MRI (7/12; 58%). However, benign wedge-shaped lesions were predominantly mildly hypointense (13/23; 57%) on ADC maps and showed no early enhancement (15/23; 65%). Histologic correlates of the benign wedge-shaped regions showed prostatitis (acute inflammation [7/23; 30%] or chronic inflammation [9/23; 39%]), hemosiderin-laden macrophages (6/23; 26%), prominent blood vessels (7/23; 30%), intraluminal blood (6/23; 26%), and nonspecific atrophy (6/23; 26%). The mean (± SD) quantitative ADC value of malignant wedge-shaped regions (1.13 ± 0.11 μm/ms) was significantly lower (p = 0.0001) than that of benign wedge-shaped regions (1.52 ± 0.27 μm/ms).
This study shows that a greater percentage of wedge-shaped features are malignant than was previously thought. Of importance, mpMRI (specifically, ADC maps) can distinguish between malignant and benign wedge-shaped features.
本研究旨在探讨 T2 加权图像上观察到的楔形病变的多参数 MRI（mpMRI）特征和病理结果。
76 例经组织学证实的前列腺癌患者在接受根治性前列腺切除术前行术前 3T MRI 检查。两位放射科医生共同对 T2 加权图像上的楔形低信号区域进行标记，并评估其在表观扩散系数（ADC）图上的表现（以确定低信号程度）和动态对比增强（DCE）MRI（DCE-MRI）（以评估其是否表现出早期增强）。通过回顾性地将 MR 图像与整个组织学标本进行匹配来评估楔形病变的病理结果。使用 t 检验评估恶性和良性楔形病变的 ADC 值之间的差异。
共识别出 35 个楔形区域，其中 12 个（34%）为恶性。大多数恶性楔形区域在 ADC 图上呈高度低信号（10/12；83%），在 DCE-MRI 上表现为早期增强（7/12；58%）。然而，良性楔形病变在 ADC 图上主要呈轻度低信号（13/23；57%），无早期增强（15/23；65%）。良性楔形病变的组织学相关性显示前列腺炎（急性炎症[7/23；30%]或慢性炎症[9/23；39%]）、含铁血黄素巨噬细胞（6/23；26%）、突出的血管（7/23；30%）、管腔内血液（6/23；26%）和非特异性萎缩（6/23；26%）。恶性楔形病变的平均（±标准差）ADC 值（1.13±0.11μm/ms）明显低于良性楔形病变（1.52±0.27μm/ms）（p=0.0001）。
本研究表明，楔形特征中恶性的比例高于之前认为的比例。重要的是，mpMRI（特别是 ADC 图）可以区分恶性和良性楔形特征。
