48岁男性，因胰管腺癌行保留幽门胰十二指肠切除术及肠系膜上静脉切除术及重建(T3N1)。A.轴位增强CT示1.7 cm病变(箭头)，肠系膜上动脉左侧边界不清。B.轴位t2加权像，肿块至椎旁肌高信号(箭头)。C.动脉期t1加权显像，与未增强图像相比，肿块轻度增强(箭头);增强模式分类为早期。D. DWI b值800mm2 /s，肿块至椎旁肌高信号(箭头)。E.在ADC图上，视觉上肿块呈低信号(箭头)至椎旁肌。结果表明存在定性扩散限制;病变ADC值为0.96 × 10−3 mm2/s。F. MRI后6个月CT轴位图显示病灶最大轴径增大大于5mm(箭头)，提示软组织异常为局部肿瘤复发。
May 25, 2022 —According to ARRS’ American Journal of Roentgenology (AJR),addingdiffusion-weighted MRI(DWI) to conventionalMRIimproves the differentiation of locally recurrent tumor and post-surgical fibrosis afterpancreatic ductal adenocarcinoma(PDAC) resection, primarily due to improved sensitivity for recurrence.
“The findings indicate a potential role for MRI with DWI in surveillance protocols after PDAC resection,” clarified corresponding authorTae Wook Kang, MDfrom Samsung Medical Center in Seoul, South Korea.
Kang and colleagues’ retrospective study included 66 patients (35 men, 31 women; mean age, 60.5 years) with PDAC resection between January 2009 and March 2016, who underwent postoperative surveillance CT demonstrating a soft tissue lesion at the operative site or at the site of peripancreatic vessels and subsequent MRI with DWI for further evaluation. CT at least 6 months after MRI served as reference standard, with increase in size of the soft tissue by ≥5 mm differentiating locally recurrent tumor (n=26) and post-surgical fibrosis (n=40). Two observers independently reviewed MRI examinations in separate sessions: conventional MRI alone vs MRI with DWI.
Compared with MRI alone, MRI and DWI showed higher sensitivity (observer 1: 88.5% vs 61.5%, p=.008; observer 2: 84.6% vs 42.3%, p= .001) without difference in specificity (observer 1: 72.5% vs 80.0%, p=.08; observer 2, 95.0% vs 85.0%, p=.10) in detecting local recurrence after PDAC resection.
“MRI with DWI as a problem-solving tool during post-operative surveillance after PDAC resection could facilitate earlier detection of recurrences,”the authors of this AJR article added, “guiding prognostic assessment and treatment decisions.”
For more information:www.arrs.org
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