Department of Radiology, Hospital de Base, São José do Rio Preto Medical School (FAMERP), São José do Rio Preto, São Paulo, Brazil.
PLoS One. 2013 Dec 6;8(12):e81509. doi: 10.1371/journal.pone.0081509. eCollection 2013.
Differentiating between infectious and neoplastic focal brain lesions that are detected by conventional structural magnetic resonance imaging (MRI) may be a challenge in routine practice. Brain perfusion-weighted MRI (PWI) may be employed as a complementary non-invasive tool, providing relevant data on hemodynamic parameters, such as the degree of angiogenesis of lesions. We aimed to employ dynamic susceptibility contrast-enhanced perfusion MR imaging (DSC-MRI) to differentiate between infectious and neoplastic brain lesions by investigating brain microcirculation changes.
DSC-MRI perfusion studies of one hundred consecutive patients with non-cortical neoplastic (n = 54) and infectious (n = 46) lesions were retrospectively assessed. MRI examinations were performed using a 1.5-T scanner. A preload of paramagnetic contrast agent (gadolinium) was administered 30 seconds before acquisition of dynamic images, followed by a standard dose 10 seconds after starting imaging acquisitions. The relative cerebral blood volume (rCBV) values were determined by calculating the regional cerebral blood volume in the solid areas of lesions, normalized to that of the contralateral normal-appearing white matter. Discriminant analyses were performed to determine the cutoff point of rCBV values that would allow the differentiation of neoplastic from infectious lesions and to assess the corresponding diagnostic performance of rCBV when using this cutoff value.
Neoplastic lesions had higher rCBV values (4.28±2.11) than infectious lesions (0.63±0.49) (p<0.001). When using an rCBV value <1.3 as the parameter to define infectious lesions, the sensitivity of the method was 97.8% and the specificity was 92.6%, with a positive predictive value of 91.8%, a negative predictive value of 98.0%, and an accuracy of 95.0%.
PWI is a useful complementary tool in distinguishing between infectious and neoplastic brain lesions; an elevated discriminatory value for diagnosis of infectious brain lesions was observed in this sample of patients when the rCBV cutoff value was set to 1.3.
在常规的结构性磁共振成像（MRI）检测中，区分感染性和肿瘤性局灶性脑病变可能具有挑战性。脑灌注加权 MRI（PWI）可以作为一种补充的非侵入性工具，提供有关病变血管生成程度等血流动力学参数的相关数据。我们旨在通过研究脑微循环变化，利用动态对比增强灌注 MRI（DSC-MRI）来区分感染性和肿瘤性脑病变。
回顾性评估了 100 例非皮质性肿瘤性（n=54）和感染性（n=46）病变患者的 DSC-MRI 灌注研究。MRI 检查在 1.5-T 扫描仪上进行。在采集动态图像前 30 秒给予预加载顺磁性对比剂（钆），然后在开始图像采集后 10 秒给予标准剂量。通过计算病变实性区域的局部脑血容量（rCBV）值，将其标准化为对侧正常白质的 rCBV 值，来确定 rCBV 值。进行判别分析以确定区分肿瘤性和感染性病变的 rCBV 值的临界点，并评估使用该临界值时 rCBV 的相应诊断性能。
肿瘤性病变的 rCBV 值（4.28±2.11）高于感染性病变（0.63±0.49）（p<0.001）。当使用 rCBV 值<1.3 作为定义感染性病变的参数时，该方法的灵敏度为 97.8%，特异性为 92.6%，阳性预测值为 91.8%，阴性预测值为 98.0%，准确性为 95.0%。
PWI 是区分感染性和肿瘤性脑病变的有用的补充工具；在该患者样本中，当 rCBV 截断值设定为 1.3 时，观察到对诊断感染性脑病变的区分诊断值升高。
