Estimation of pulmonary hypertension by perfusion lung scintigraphy: gravitational effect of postural changes between the lateral decubitus positions

To estimate pulmonary hypertension in patients with various heart diseases, we devised a new method using perfuison lung scintigraphy with technetium-99m-labelled macroaggregated albumin. In this method, changes in the distribution of pulmonary perfusion caused by gravitational effects, namely, changes in the total count ratios of the right lung against the left lung between right and left lateral decubitus positions (rt/lt), were assessed in 62 patients and in 10 normal subjects. The rt/lt ratios were calculated as indices of the above changes. They correlated significantly with mean pulmonary arterial pressure (mPAP) (= –0.62,P < 0.001), pulmonary capillary wedge pressure ( = –0.63,P < 0.001) and pulmonary arteriolar resistance ( = 0.50,P < 0.001) in all subjects. In 17 patients with valvular heart diseases, the ratio correlated significantly with mPAP ( = – 0.84,P < 0.001). In 10 patients with various heart diseases, the U/S ratio, i.e. the index of changes in the count ratios of the upper field against the lower field for the right lung following postural change from the upright to the supine position, was also obtained as well as the rt/lt ratio. The latter evidenced a better correlation with mPAP ( = –0.90,P < 0.001) than the former (=–0.64,P < 0.05). We conclude that this method is valuable as a noninvasive approach for the estimation of pulmonary hypertension.     

Renal uptake on lung perfusion scintigraphy in a patient with primary pulmonary hypertension

An 18-year-old woman presented with primary pulmonary hypertension (PPH) and was hospitalized because of hemoptysis and was referred to our department for a differential diagnosis pulmonary thromboembolism. Doppler ultrasonography of the lower extremities was normal. Echocardiography and cardiac catheterization showed right ventricular dilatation and increased pulmonary artery pressure without anatomic (intracardiac) shunt. The mean pulmonary arterial pressure was 110 mm Hg. Tc-99m MAA lung perfusion scans showed nonsegmental patchy defects. Extrapulmonary renal uptake and increased systemic deposition of radiotracer were seen in the MAA scintigraphy. It could be related to a functional intrapulmonary shunt resulting in increasing pressure in the pulmonary artery in PPH.     

双能量CT肺灌注及血管成像与核素肺通气灌注成像诊断肺栓塞的对照研究

目的 通过与核素肺通气灌注显像比较,评价双能量CT肺血管成像(DE-CTPA)及双能量CT肺灌注成像(DE-CTLP)技术诊断肺栓塞的能力.方法 比较50例临床怀疑肺栓塞的患者DE-CTPA、DE-CTLP及核素肺通气灌注显像结果,以非线性相关检验比较DE-CTPA显示肺血管腔内充盈缺损与DE-CTLP显示灌注缺损之间的相关性,以核素为参考标准,应用一致性检验方法(Kappa检验)对照分析两者之间的一致性及DE-CTLP诊断肺栓塞的敏感性和特异性.结果 (1)50例临床怀疑肺栓塞患者中,4例CT图像质量差,不能评价.余46例共920个有效肺段中,DE-CTPA显示262个肺段肺血管腔内充盈缺损,DE-CTLP显示266个肺段明确灌注缺损.核素肺通气灌注扫描显示268个肺段灌注与通气不匹配.(2)DE-CTLP与DE-CTPA两者间显著相关(r=0.883,P<0.01);DE-CTLP与核素肺通气灌注显像的一致性良好(Kappa=0.940,P<0.01);以核素肺通气灌注成像为诊断参考标准,应用DE-CTLP诊断肺栓塞的阳性预测值95.5%(279/292),阴性预测值98.3%(641/652),敏感性96.2%(279/290),特异性98.0%(641/654).(3)应用CareDose 4D技术,DE-CTPA和DE-CTLP患者平均射线损伤剂量为(4.37±0.47)mSv.结论 应用DE-CTPA和DE-CTLP技术可以在一次扫描中同时获得常规CT肺血管成像的血管形态学信息和肺实质血流灌注情况,为临床诊断肺栓塞提供直观、有效的综合影像信息.     

Pulmonary arterial hypertension: value of perfusion scintigraphy

Records of 34 patients with established causes of pulmonary arterial hypertension were retrospectively reviewed. The ventilation-perfusion scans were blindly classified according to standardized criteria as normal or high, low, or intermediate probability of pulmonary embolism as the cause of pulmonary arterial hypertension. Twelve of 13 patients with primary pulmonary hypertension had normal or low-probability scans, but the perfusion pattern was not helpful in distinguishing between histologic subtypes. All eight patients with large-vessel thromboembolic hypertension had high-probability scans; however, three of 13 patients with nonembolic secondary pulmonary hypertension also had high-probability scans. While a normal or low-probability scan excluded proximal pulmonary emboli as a cause of pulmonary hypertension, a high-probability scan may be associated with a variety of other nonembolic causes of secondary pulmonary hypertension.     

肺通气/灌注显像与多层螺旋CT诊断慢性血栓栓塞性肺动脉高压的对比研究

目的 对比肺通气/灌注(V/Q)显像与多层螺旋CT肺血管造影(CTPA)诊断慢性血栓栓塞性肺动脉高压(CTEPH)的准确性,评价2种影像学方法的诊断符合程度.方法 49例肺动脉高压患者,经超声心动图排除瓣膜性心脏病和先天性心脏病,既往无急性肺栓塞病史.所有患者先后行肺V/Q显像和CTPA检查,并以肺动脉造影为"金标准"进行对比评价.对V/Q显像和CTPA检查结果比较进行χ2检验,采用SPSS 12.0统计软件.结果 肺V/Q显像对CTEPH的诊断灵敏度、特异性和准确性分别为100.0%(17/17),71.9%(23/32)和81.6%(40/49),CTPA分别为94.1%(16/17),81.2%(26/32)和85.7%(42/49).肺V/Q显像与CTPA的诊断符合率为75.5%(37/49),Kappa值为0.513,2种影像学方法的诊断结果差异无统计学意义(χ2=0.75,P>0.05).结论 肺V/Q显像和CTPA均是诊断CTEPH有效的无创性影像学方法,两者结合应用有助于更好地诊断CTEPH.     

Correlation between lung perfusion blood volume and SPECT images in patients with chronic thromboembolic pulmonary hypertension by balloon pulmonary angioplasty

ObjectivesWe evaluated the reperfusion by balloon pulmonary angioplasty (BPA) in lung PBV and SPECT images.MethodsIn total, 17 patients and 57 sessions were evaluated. Pre-BPA and post-BPA lung PBV and SPECT/CT images, based on both anatomical segments and physiologic regions (upper/middle/lower) were compared.ResultsBPA had a positive effect on most hypoperfused/unperfused segments/regions. There was generally a high rate of agreement between PBV measurements and SPECT/CT.ConclusionsBPA shows promise as a treatment modality for CTEPH patients. SPECT/CT, and, to a lesser extent, PBV, were useful in indicating areas in need of balloon angioplasty.     

Acute pulmonary embolism: comparison and integration of perfusion lung scintigraphy with multislice spiral CT

PURPOSE: This study compared and integrated the data from perfusion lung scintigraphy and multislice computed tomography (CT) for the emergency diagnosis of acute pulmonary embolism in nuclear medicine and radiology departments operating around the clock. MATERIALS AND METHODS: One hundred and seven patients with a clinical and laboratory suspicion of acute pulmonary embolism who had already undergone chest radiography were divided into four groups according to the time interval between onset of clinical suspicion and performance of the two diagnostic examinations (0-24 h, 24-48 h, 0-48 h, 2-7 days). Cohen's test for the analysis of statistical concordance was used. RESULTS: Perfusion lung scintigraphy and multislice CT were positive in 29/107 (27.1%) and negative in 78/107 (72.89%). Positive concordance (PC) was found in 22 cases and negative concordance (NC) in 71 cases: 0-24 h: PC in 12, NC in 32 cases; 24-48 h: PC in 3, NC in 15 cases; 0-48 h: PC in 15, NC in 47 cases; 2-7 days: PC in 7, NC in 24 cases. CONCLUSIONS: Perfusion lung scintigraphy and multislice CT demonstrated elevated concordance if performed within 7 days of the onset of suspicion of acute pulmonary embolism. Concordance was higher if the examinations were completed within 24-48 h. In suspected acute pulmonary embolism, it is mandatory to reach a correct diagnosis within few hours--48 at the most.     

99mTc technegas ventilation and perfusion lung scintigraphy for the diagnosis of pulmonary embolus.

Lung scintigraphy is used widely for diagnosis of pulmonary embolus (PE). Technegas ventilation imaging has many advantages over other methods, but little outcome data exists on this technique. The aims of this study were to better define the role of lung scintigraphy in the management of patients with suspected PE and to evaluate technegas ventilation imaging by following patient outcomes. METHODS: A group of 717 out of 834 consecutive patients, referred to a university teaching hospital for lung scintigraphy to confirm or refute the diagnosis of PE, was followed for 18-30 mo to determine clinical outcome. The follow-up endpoints were death as a result of PE, death as a result of hemorrhage after treatment for PE, uncomplicated survival, survival with subsequent PE, nonfatal hemorrhage after treatment for PE and recurrence of PE in treated patients. Ventilation imaging was performed using technegas, and perfusion imaging was performed using intravenous 99mTc macroaggregated albumin. The modified PIOPED (Prospective Investigation of Pulmonary Embolism Diagnosis) diagnostic criterion was used for interpretation of lung scintigraphy. RESULTS: Diagnostic results included 3.5% normal studies, 67.4% assessed as low probability for PE, 10% as moderate probability for PE and 19.1% as high probability for PE. A total of 231 patents received therapy with heparin, followed by warfarin, including those receiving anticoagulation therapy for other conditions. Ninety-six percent of patients with normal and low probability studies (n = 508) had good outcomes, 6 patients died as a result of PE and 12 subsequently developed PE. The odds ratio for death by PE in this group was 0.2. Of the 72 moderate probability studies, 39 patients were untreated. In this group there was 1 death due to PE, and PE subsequently developed in 2 patients. None of the remaining 33 treated patients died, but 4 patients experienced bleeding complications. The odds ratio for death by PE in the moderate probability group was 0.7. In those patients with high-probability studies, there were 8 deaths by PE, 6 deaths by hemorrhage, 11 nonfatal hemorrhages and 7 patients who experienced recurrences of PE. The odds ratios in this group were 6 and 10 for death by PE, or death by PE and the treatment of PE, respectively. CONCLUSION: The use of the modified PIOPED diagnostic classification is valid for technegas lung scintigraphy. Using technegas, normal/low-probability and high-probability results are highly predictive of respective outcomes. Technegas lung scintigraphy reduces the number of indeterminate studies.     

Evaluation by ventilation and perfusion scintigraphy in patients who developed postural hypoxemia in the supine position

Ventilation and pulmonary perfusion scintigraphy were performed in 7 patients in whom postural change from the sitting position to the supine position decreased partial oxygen pressure in arteries (PaO₂) by 15 mmHg or more. Six of these 7 patients were obese. Five patients had organic pulmonary disease or space occupying lesions of the liver. On lateral supine-position images taken by using the continuous inhalation method for^81mKr ventilation scintigraphy, ventilation was reduced in the dorsal area corresponding to a gravity-dependent area, but on pulmonary perfusion scintigrams, there were no marked changes compared to normal adults. The mismatch of ventilation to perfusion may have caused hypoxemia. Reduced ventilation was correlated with reduced PaO₂. The distribution of^81mKr bolus gas inhalation suggested closure of the airway in the dorsal area at functional residual capacity (FRC), which means the resting expiratory level, in the supine position.     

Quantitative analysis of lung perfusion in patients with primary pulmonary hypertension.

The aim of this study was to evaluate quantitatively the heterogeneity of lung perfusion scans in patients with primary pulmonary hypertension (PPH) and to compare it with the severity of disease. METHODS: Lung perfusion scans were obtained on 22 patients with PPH and 12 age-matched control subjects. The perfused area rates (PARs) were calculated by dividing the lung area in each 10% threshold width from 10% to 100% of maximal counts by total lung area. The total absolute difference in the PAR between each patient and the mean control value was assumed as the perfusion index of the lung (P index). The P index was compared with hemodynamic parameters and the right ventricular ejection fraction (RVEF), including 7 patients who received long-term vasodilator therapy. RESULTS: The P index correlated significantly with mean pulmonary arterial pressure (P < 0.001) and RVEF (P < 0.05). In patients with vasodilator therapy, the P index was improved significantly after therapy (P < 0.05) and was associated with a reduction in pulmonary arterial pressure. CONCLUSION: Quantitative assessment of lung perfusion irregularity might provide useful information about the severity of disease and the effect of therapy in addition to the routine visual representation.     

肺灌注显像定量分析评价特发性肺动脉高压

目的探讨肺灌注显像肺血流灌注分布指数（简称P指数）定量分析法评价特发性肺动脉高压（IPAH）的应用价值。方法选取30例临床确诊的IPAH患者,行肺灌注显像和右心导管检查。应用美国国立卫生研究院开发的开源软件NIHImage进行P指数定量分析,同时选取12名年龄相匹配的健康对照者进行肺灌注显像,以得到灌注面积百分比标准曲线,并对全部30例患者的P指数和血流动力学参数进行Pearson相关性分析。按肺灌注显像特点将患者分为3组（双肺放射性分布均匀;双肺放射性分布不均匀,肺尖部放射性浓聚;双肺放射性分布明显不均匀,呈“斑片状”稀疏和缺损改变）,比较各组间P指数的差异。采用SPSS11．0软件,组间比较行student’st检验。结果P指数与平均肺动脉压（mPAP）及全肺阻力（TPR）呈直线相关性,P指数与mPAP的相关系数为0．541（P〈0．01）,与TPR的相关系数为0．573（P〈0．01）。图像定性分析3种特征性图像的P指数分别为9．47±1．06,13．77±4．57和18．97±5．93,呈递增趋势（t值分别为-2．83,-5．68和-2．65,P均〈0．05）;mPAP、TPR亦依次呈递增趋势,但差异无统计学意义（t=-1．990～0．236,P均〉0．05）。结论肺灌注显像P指数定量分析法能够准确反映肺动脉压力和TPR等血流动力学状态,对IPAH的诊断和疗效判断具有较好的应用前景。     

Dynamic perfusion MRI versus perfusion scintigraphy: prediction of postoperative lung function in patients with lung cancer

OBJECTIVE: The purpose of this study was to determine the capability of dynamic perfusion MRI as an alternative to pulmonary perfusion scintigraphy for prediction of postoperative lung function in patients with lung cancer. SUBJECTS AND METHODS. Sixty patients with lung cancer (35 men, 25 women) underwent dynamic perfusion MRI, perfusion scintigraphy, and preoperative and postoperative pulmonary function tests (forced expiratory volume in 1 sec [FEV(1)]). Perfusion MRIs were obtained with a 3D turbo field-echo sequence (TR/TE, 2.7/0.6; flip angle, 40 degrees; matrix, 128 x 96) using a 1.5-T scanner. Regional blood flow was calculated from the signal intensity-time curves after bolus injection of contrast medium on MRI (Q(MRI)) and uptake ratios of radioisotope on perfusion scintigraphy (Q(PS)). Postoperative lung functions predicted by MRI (FEV(1,MRI)) and perfusion scintigraphy (FEV(1,PS)) were calculated from preoperative FEV(1) and regional Qs. To determine the capability of MRI as an alternative to scintigraphy, we evaluated correlations and the limits of agreement between predicted FEV(1,MRI) and postoperative FEV(1) and between predicted FEV(1,PS) and postoperative FEV(1). RESULTS: The correlation coefficient of postoperative FEV(1) with FEV(1,MRI) (r = 0.93, p < 0.0001) was better than that with FEV(1,PS) (r = 0.89, p < 0.0001). The limits of agreement between postoperative FEV(1) and predicted FEV(1,MRI) (0.9% +/- 10.4%) were smaller than those between postoperative FEV(1) and predicted FEV(1,PS) (2.1% +/- 13.2%). CONCLUSION: Dynamic perfusion MRI is a feasible alternative to pulmonary perfusion scintigraphy for predicting postoperative lung function in patients with lung cancer.     

Unilateral absence of lung perfusion on pulmonary scintigraphy secondary to lung cancer with extensive pleural metastases from lung cancer.

A man with a 20-year history of smoking who underwent Tc-99m MAA Pulmonary perfusion imaging, which showed virtually absent perfusion of the right lung and fairly normal perfusion of the left lung. Eighteen days after the study, the patient died; at autopsy poorly differentiated carcinoma of the right lung was confirmed, which included extensive thickened pleura and plaques deposits and compression of the right lung; 200 ml of bloody pleural effusion was also found on the right side. The unilateral absence of lung perfusion on Tc-99m MAA pulmonary scintigraphy might reflect the autopsy findings of the right lung and pleura.     

Dual-energy CT perfusion and angiography in chronic thromboembolic pulmonary hypertension: diagnostic accuracy and concordance with radionuclide scintigraphy

Objectives

To evaluate the diagnostic accuracy of dual-energy computed tomography (DECT) perfusion and angiography versus ventilation/perfusion (V/Q) scintigraphy in chronic thromboembolic pulmonary hypertension (CTEPH), and to assess the per-segment concordance rate of DECT and scintigraphy.

Methods

Forty consecutive patients with proven pulmonary hypertension underwent V/Q scintigraphy and DECT perfusion and angiography. Each imaging technique was assessed for the location of segmental defects. Diagnosis of CTEPH was established when at least one segmental perfusion defect was detected by scintigraphy. Diagnostic accuracy of DECT perfusion and angiography was assessed and compared with scintigraphy. In CTEPH patients, the per-segment concordance between scintigraphy and DECT perfusion/angiography was calculated.

Results

Fourteen patients were diagnosed with CTEPH and 26 with other aetiologies. DECT perfusion and angiography correctly identified all CTEPH patients with sensitivity/specificity values of 1/0.92 and 1/0.93, respectively. At a segmental level, DECT perfusion showed moderate agreement (κ?=?0.44) with scintigraphy. Agreement between CT angiography and scintigraphy ranged from fair (κ?=?0.31) to slight (κ?=?0.09) depending on whether completely or partially occlusive patterns were considered, respectively.

Conclusions

Both DECT perfusion and angiography show satisfactory performance for the diagnosis of CTEPH. DECT perfusion is more accurate than angiography at identifying the segmental location of abnormalities.

Key Points

? Chronic thromboembolic pulmonary hypertension (CTEPH) is potentially treatable by surgery. ? Dual-energy computed tomography (DECT) allows angiography and perfusion using a single acquisition. ? Both DECT perfusion and angiography showed satisfactory diagnostic performance in CTEPH. ? DECT perfusion was more accurate than angiography in identifying segmental abnormalities.     

Diagnosis of pulmonary embolism: ventilation perfusion scintigraphy versus helical computed tomography pulmonary angiography

The present study compared the accuracy of ventilation perfusion scintigraphy (VQS) and CT pulmonary angiography (CTPA) for the diagnosis of pulmonary embolism. This was a prospective observational study of 112 patients with suspected pulmonary embolism (PE) who could be studied with both investigations within 24 h. Results were compared to final diagnosis at completion of 6-month follow up, using receiver operating characteristic (ROC) analysis. Pulmonary embolism was diagnosed in 27 referred patients (24%). The sensitivity and specificity of VQS and CTPA were similar to that reported from the literature. A normal VQ scan had the highest negative predictive value (100%), while a high-probability VQ scan had the highest positive predictive value (92%). There was no overall difference (area under the ROC curve (AUC)) between VQS (AUC (95% CI) = 0.82 (0.75,0.89)) and CTPA (AUC = 0.88 (0.81,0.94)) for the diagnosis of PE. Among patients with abnormal chest X-rays, CTPA (AUC 0.90 (0.83,0.97)) appeared somewhat better than VQS (AUC 0.78 (0.68,0.88)) but this difference did not reach statistical significance. In this instance, CTPA is at least as accurate as VQS and may provide an opportunity to make alternative diagnoses.     

肺通气/灌注显像预测肺癌术后肺功能

目的 利用肺通气/灌注显像预测肺癌切除术后残余肺功能及评价手术适应证.方法 26例原发性肺癌患者：21例行肺灌注/通气显像,其中13例行手术治疗;5例行肺灌注显像行手术治疗;所有患者于术前1周左右行肺功能检查,其中18例手术治疗患者于术后2个月再次行肺功能检查.采用Neuhaus公式计算术后肺功能：第1秒用力呼气量预测值（ppoFEV1）.对通气、灌注显像2种方法计算所得的ppoFEV1值进行t检验,并分别与术后2个月肺功能实测值进行t检验和相关性分析.结果 21例患者通气法ppoFEV1为（1.347±0.539）L,灌注法ppoFEV1为（1.410±0.543）L,差异无统计学意义（t=0.062,P＞0.05）;13例手术者其中术前通气ppoFEV1为（1.545±0.588）L,术后2个月实测值为（1.450±0.521）L,差异无统计学意义（t=0.092,P＞0.05）.所有18例手术者术前灌注ppoFEV1为（1.697±0.546）L,术后2个月实测值为（1.457±0.488）L,差异无统计学意义（t=0.017,P＞0.05）.13例肺通气法ppoFEV1与术后2个月实测值显著相关,r=0.950,P＜0.01;肺灌注法ppoFEV1值与术后2个月实测值也显著相关,r=0.937,P＜0.01.18例肺灌注法ppoFEV1与术后2个月实测值也显著相关（r=0.922,P＜0.01）.结论 肺通气/灌注显像结合肺功能测定有利于判断肺癌患者尤其合并低肺功能患者能否进行手术及确定手术部位和范围,能用于预测肺癌切除术后残余肺功能.