Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 135-710, Korea.
Eur Radiol. 2014 Mar;24(3):677-84. doi: 10.1007/s00330-013-3054-0. Epub 2013 Nov 1.
To evaluate the usefulness of diffusion-weighted (DW) magnetic resonance images for distinguishing non-neoplastic cysts from solid masses of indeterminate internal characteristics on computed tomography (CT) in the mediastinum.
We enrolled 25 patients with pathologically proved mediastinal masses who underwent both thoracic CT and magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI). MRI was performed in patients with mediastinal masses of indeterminate internal characteristics on CT. Two thoracic radiologists evaluated the morphological features and quantitatively measured the net enhancement of the masses at CT. They also reviewed MR images including unenhanced T1- and T2-weighted images, gadolinium-enhanced images and DW images.
The enrolled patients had 15 solid masses and ten non-neoplastic cysts. Although the morphological features and the extent of enhancement on CT did not differ significantly between solid and cystic masses in the mediastinum (P > 0.05), non-neoplastic cysts were distinguishable from solid masses by showing signal suppression on high-b-value DW images or high apparent diffusion coefficient (ADC) values of more than 2.5 × 10(-3) mm(2)/s (P < 0.001). ADC values of non-neoplastic cysts (3.67 ± 0.87 × 10(-3) mm(2)/s) were significantly higher than that of solid masses (1.46 ± 0.50 × 10(-3) mm(2)/s) (P < 0.001).
DWI can help differentiate solid and cystic masses in the mediastinum, even when CT findings are questionable.
• Non-invasive diagnosis of non-neoplastic cysts can save surgical biopsy or excision. • Conventional CT or MRI findings cannot always provide a confident diagnosis. • Mediastinal masses can be well-characterised with DWI. • Non-neoplastic mediastinal cysts show significantly higher ADC values than cystic tumours. • DWI is useful to determine treatment strategy.
评估弥散加权（DW）磁共振成像在区分胸部计算机断层扫描（CT）上表现为不定内部特征的非肿瘤性囊肿与实体肿块的有用性。
我们纳入了 25 名经病理证实的纵隔肿块患者，这些患者均进行了胸部 CT 和磁共振成像（MRI）检查，包括弥散加权成像（DWI）。MRI 是在 CT 上发现纵隔肿块具有不定内部特征的患者中进行的。两名胸部放射科医生评估了肿块的形态特征，并在 CT 上对肿块的净增强程度进行了定量测量。他们还回顾了包括未增强 T1 和 T2 加权图像、钆增强图像和 DW 图像在内的 MR 图像。
纳入的患者中，有 15 个实性肿块和 10 个非肿瘤性囊肿。尽管纵隔内实性和囊性肿块的 CT 形态特征和增强程度无显著差异（P>0.05），但非肿瘤性囊肿在高 b 值 DW 图像上表现为信号抑制或表观扩散系数（ADC）值高于 2.5×10(-3)mm(2)/s（P<0.001）时，可与实性肿块相区分。非肿瘤性囊肿的 ADC 值（3.67±0.87×10(-3)mm(2)/s）显著高于实性肿块（1.46±0.50×10(-3)mm(2)/s）（P<0.001）。
DWI 有助于区分纵隔内的实性和囊性肿块，即使 CT 结果可疑也是如此。
非侵袭性诊断非肿瘤性囊肿可避免外科活检或切除。
常规 CT 或 MRI 结果不能总是提供明确的诊断。
DWI 可很好地对纵隔肿块进行特征描述。
非肿瘤性纵隔囊肿的 ADC 值明显高于囊性肿瘤。
DWI 有助于确定治疗策略。
