Gumuser Gul, Pirildar Timur, Tarhan Serdar, Batok Dilek, Ruksen Ebru, Sakar Aysin, Sayit Elvan
Department of Nuclear Medicine, School of Medicine, Celal Bayar University, Manisa, Turkey.
Nucl Med Commun. 2011 May;32(5):363-8. doi: 10.1097/MNM.0b013e328341a375.
Behçet's disease (BD) is a multisystem disorder that is characterized by vasculitis, and consists of a triad of recurrent ulcers of the oral and genital mucosa with relapsing uveitis. The prevalence of pulmonary involvement varies in the range of 1-10% in various studies, and its complications are severe and life threatening. To objectively assess the degree of pulmonary vascular endothelial damage in BD, the lung uptake, and the clearance rate of technetium-99m-hexamethylpropylene amine oxime (Tc-99m-HMPAO) were determined.
Twenty-three nonsmoking patients with BD (10 female, 13 male) and 11 (six female, five male) healthy nonsmoking controls underwent Tc-99m-HMPAO lung scanning, pulmonary function tests (PFT), chest radiograph examination, contrast-enhanced spiral chest computed tomography scanning, and high-resolution computed tomography examinations. Immediately after the bolus injection of 740 MBq of Tc-99m-HMPAO posterior sequential images were obtained at 1-s intervals for 150 s and subsequent images were obtained at one frame per minute (min) over a 10-min period, using a double-headed gamma camera equipped with a low-energy all-purpose parallel hole collimator. Dynamic images were used to calculate the Tc-99m-HMPAO lung clearance rate (T1/2). Simultaneously, a static anterior image, including a large part of the liver, was obtained of 5-min duration at 10 min after the injection. Regular regions of interests were drawn over the midportion of the right lung and the highest activity area of the liver parenchyma was selected and lung/liver (L/Li) uptake ratios were calculated to represent the degree of pulmonary vascular endothelial damage.
Chest radiograph, high-resolution computed tomography, and computed tomography findings in patients with BD were nonspecific for BD. There was also a statistically significant difference between patients with BD (30.26 ± 10.55 s) and normal controls (19.53 ± 6.24 s) on their T1/2 values (P = 0.0004). The results show that the L/Li ratios on the Tc-99m-HMPAO lung scan were significantly higher in patients with BD (0.60 ± 0.19) than those in normal controls (0.39 ± 0.07) (P = 0.0021). Using a cutoff value of 0.50, 15 of 23 (65%) patients with BD had increased L/Li ratios. No correlation was found between the mean T1/2 values of Tc-99m-HMPAO clearance and the PFT in patients with BD. The L/Li ratios were not correlated with PFT in patients with BD.
The degree of pulmonary vascular endothelial damage was represented as increased L/Li ratios and decreased lung clearance rate measured on the Tc-99m-HMPAO lung scan in patients with BD. Our results indicated that determining the T1/2 values and the L/Li ratios on Tc-99m-HMPAO lung imaging should be an objective method to assess subclinical pulmonary damage even in the early stages of BD in the patients.
白塞病（BD）是一种以血管炎为特征的多系统疾病，由口腔和生殖器黏膜复发性溃疡以及复发性葡萄膜炎组成三联征。在各项研究中，肺部受累的患病率在1%至10%之间，其并发症严重且危及生命。为客观评估白塞病患者肺血管内皮损伤程度，测定了99m锝-六甲基丙烯胺肟（Tc-99m-HMPAO）的肺摄取及清除率。
23例不吸烟的白塞病患者（10例女性，13例男性）和11例（6例女性，5例男性）健康不吸烟对照者接受了Tc-99m-HMPAO肺扫描、肺功能测试（PFT）、胸部X线检查、对比增强螺旋胸部计算机断层扫描以及高分辨率计算机断层扫描检查。在静脉推注740 MBq的Tc-99m-HMPAO后，立即使用配备低能通用平行孔准直器的双头γ相机，以1秒间隔获取150秒的后位序列图像，随后在10分钟内每分钟获取一帧图像。利用动态图像计算Tc-99m-HMPAO肺清除率（T1/2）。同时，在注射后10分钟获取一张包括大部分肝脏的静态前位图像，时长5分钟。在右肺中部绘制常规感兴趣区，并选择肝实质的最高活性区域，计算肺/肝（L/Li）摄取比值以代表肺血管内皮损伤程度。
白塞病患者的胸部X线、高分辨率计算机断层扫描及计算机断层扫描结果对白塞病无特异性。白塞病患者的T1/2值（30.26±10.55秒）与正常对照者（19.53±6.24秒）之间也存在统计学显著差异（P = 0.0004）。结果显示，白塞病患者Tc-99m-HMPAO肺扫描的L/Li比值（0.60±0.19）显著高于正常对照者（0.39±0.07）（P = 0.0021）。以0.50为临界值，23例白塞病患者中有15例（65%）的L/Li比值升高。白塞病患者中，Tc-99m-HMPAO清除的平均T1/2值与肺功能测试之间未发现相关性。白塞病患者的L/Li比值与肺功能测试也无相关性。
白塞病患者肺血管内皮损伤程度表现为Tc-99m-HMPAO肺扫描中L/Li比值升高及肺清除率降低。我们的结果表明，测定Tc-99m-HMPAO肺成像的T1/2值和L/Li比值应是评估白塞病患者即使在疾病早期亚临床肺损伤的一种客观方法。
