Huang Yao, Wu Ning, Lin Dong-mei, Li Lin, Wang Jian-wei
Department of Diagnostic Radiology, Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China.
Zhonghua Zhong Liu Za Zhi. 2005 Jun;27(6):360-3.
To evaluate imaging features of benign and malignant solitary pulmonary nodules (SPN) using dynamic computed tomography (dCT) to improve the accuracy of radiological diagnosis.
Fifty-one patients with SPN were studied by dCT. In this procedure, a bolus of 100 ml contrast medium was administrated intravenously at a rate of 4 ml/sec. The same-located dynamic scans were carried out from 15 sec to 120 sec following the injection. Time-attenuation curves (TAC) were created according to circular or oval ROI drawn over nodules. Histopathological diagnosis was considered as the golden standard in all patients. Double-blind examination and evaluation were carried out and the data were analyzed statistically with Mann-Whitney U test.
Thirty eight cases were diagnosed to be malignant SPN (mSPN) and 13 cases to be benign SPN (bSPN). The benign SPN were further divided into two groups, bSPN(1) consisting 6 cases with chronic pneumonitis, nodular tuberculosis or sclerosing hemangioma and bSPN(2) consisting 7 cases with tuberculoma, pulmonary cyst, pulmonary sequestration or mycosis ball. There were statistically significant differences between mSPN and bSPN(2) in peak heights of enhancement (87.6 HU vs. 57.8 HU, P < 0.01), enhancement values (peak heights- unenhanced CT values, 59.6 HU vs. 11.1 HU, P < 0.01). However, no statistically significant differences of those two values existed between mSPN and bSPN(1). TAC of mSPN reached to peak height more rapidly and remained a plateau. TAC of bSPN(1)s showed similar changes to that of mSPN despite a delayed reach to a peak height or even a descending branch. TAC of the bSPN(2)s was lower and flatter without peak height. If a threshold of 20 HU was taken for dCT, the lesions with < or = 20 HU were diagnosed as benign, and the lesions with > 20 HU were diagnosed as malignant, with a sensitivity of 100%, a specificity of 54.0% and an accuracy of 88.4%.
(1) Absence of the marked enhancement (< or = 20 HU) in dynamic CT is strongly predictive of benignancy. (2) The peak height and enhancement value of dCT are helpful to differentiate malignant SPNs from benign ones. (3) The TAC configuration is helpful in differentiating malignant SPNs from benign ones. Descending branches could be found in some benign lesions, but not in the malignant ones. The TAC of tuberculoma and mycosis ball is usually relatively low and flat without any peak height.
利用动态计算机断层扫描（dCT）评估良性和恶性孤立性肺结节（SPN）的影像特征，以提高放射学诊断的准确性。
对51例SPN患者进行dCT研究。在此过程中，以4ml/秒的速率静脉注射100ml造影剂团注。注射后15秒至120秒进行同部位动态扫描。根据在结节上绘制的圆形或椭圆形感兴趣区（ROI）创建时间-密度曲线（TAC）。所有患者均以组织病理学诊断为金标准。进行双盲检查和评估，并采用曼-惠特尼U检验对数据进行统计学分析。
38例被诊断为恶性SPN（mSPN），13例为良性SPN（bSPN）。良性SPN进一步分为两组，bSPN(1)组6例，包括慢性肺炎、结节性结核或硬化性血管瘤；bSPN(2)组7例，包括结核瘤、肺囊肿、肺隔离症或霉菌球。mSPN与bSPN(2)在强化峰值高度（87.6HU对57.8HU，P<0.01）、强化值（峰值高度-平扫CT值，59.6HU对11.1HU，P<0.01）方面存在统计学显著差异。然而，mSPN与bSPN(1)在这两个值上无统计学显著差异。mSPN的TAC更快达到峰值高度并保持在平台期。bSPN(1)的TAC尽管达到峰值高度延迟甚至出现下降支，但与mSPN表现出相似变化。bSPN(2)的TAC较低且较平缓，无峰值高度。若将dCT的阈值设为20HU，强化值≤20HU的病变诊断为良性，强化值>20HU的病变诊断为恶性，敏感性为100%，特异性为54.0%，准确性为88.4%。
（1）动态CT中无明显强化（≤20HU）强烈提示为良性。（2）dCT的峰值高度和强化值有助于鉴别恶性SPN与良性SPN。（3）TAC形态有助于鉴别恶性SPN与良性SPN。一些良性病变可出现下降支，而恶性病变则无。结核瘤和霉菌球的TAC通常相对较低且平缓，无峰值高度。
