Virtual pulmonary arterioscopy in pulmonary embolic disease

16 slice multidetector CT provides virtual endoscopic views of the inside of arteries, or any other hollow structures. This is performed non-invasively using post-processing of three-dimensional isotropic image data sets, acquired during standard CT examinations. These virtual endoscopic views are simultaneously correlated with the standard multiplanar reconstructions, with the ability to navigate a virtual camera through the hollow structure under study. Normal and abnormal volume rendered images of the pulmonary arteries are presented in correlation with the multiplanar reformats. The abnormal images show the volume rendered appearances of acute and chronic pulmonary embolic disease. It is also postulated that this technique has a problem solving role in the differential diagnosis of chronic mural emboli from extravascular structures such as adjacent lymph nodes or bronchiolar impaction. This technique may also have a role in medical education, providing clinicians and medical students with interactive three-dimensional representations of disease processes.     

The relationship between pulmonary artery pressure and pulmonary artery diameter in pulmonary hypertension

The pulmonary arteries dilate in response to many factors, principally increased pressure and flow. In patients who have pulmonary arterial hypertension but no increase in flow, we have compared main pulmonary artery size at computed tomography with pulmonary haemodynamic data obtained during right heart catheterisation. In patients with primary pulmonary hypertension and chronic thromboembolic pulmonary hypertension, dilatation correlated with raised pulmonary vascular resistance and reduced cardiac output but not with mean arterial pressure. In patients with chronic lung disease no correlations were shown though a trend between raised pressure and size was observed. We speculate that pulmonary artery compliance is an important factor which determines the degree of dilatation in response to raised pressure. Estimations of pressure cannot be made from measurements of pulmonary artery size without knowledge of the underlying lung disease.     

CT-determined pulmonary artery diameters in predicting pulmonary hypertension

This study was to determine if the diameters of pulmonary arteries measured from computed tomographic (CT) scans could be used 1) as indicators of pulmonary artery hypertension and 2) as a reliable base for calculating mean pulmonary artery pressure. The diameters of the main, left, proximal right, distal right, interlobar, and left descending pulmonary arteries were measured from CT scans in 32 patients with cardiopulmonary disease and in 26 age- and sex-matched control subjects. Diameters were measured using a special computer program that could display a CT density profile of the artery and its adjacent tissues. The upper limit of normal diameter for the main pulmonary artery was found to be 28.6 mm (mean + 2 SD). In the patient group, the diameters were correlated with data from cardiac catheterization. In these patients, a diameter of the main pulmonary artery above 28.6 mm readily predicted the presence of pulmonary hypertension. The calculated cross-sectional areas of the main and interlobar pulmonary arteries (normalized for body surface area [BAS]) were found to give the best estimates of mean pulmonary artery pressure (r = 0.89, P less than 0.001 and r = 0.66, P less than 0.001). Multiple regression analysis gave the useful equation: mean pulmonary artery pressure = -10.92 + 0.07646 X area of main pulmonary artery/BSA + 0.08084 X area of the right interlobar pulmonary artery/BSA (r = 0.93, P less than 0.0001). Because CT allows precise, noninvasive measurement of the diameter of pulmonary arteries, it can be of value in detecting pulmonary hypertension and estimating mean pulmonary artery pressure.     

Computed tomography pulmonary angiogram diagnosis of pulmonary embolism

Over the last decade, contrast-enhanced spiral CT has been established as a non-invasive alternative to catheter angiography and is now regarded as the first-line imaging investigation for the diagnosis of pulmonary embolism (PE). The reported sensitivities for the diagnosis of PE of spiral CT vary from 45 to 100% and the specificities vary from 78 to 100%. Prospective outcome studies have shown a high negative predictive value for a single-detector spiral CT for PE. Patients' outcomes were not adversely affected in these studies when anticoagulation was withheld after a negative CT pulmonary angiogram. The main limitation of single-detector spiral CT has been its limited ability to detect isolated subsegmental PE. However, multidetector spiral CT allows evaluation of pulmonary vessels down to sixth-order branches and significantly increases the rate of detection of PE in segmental and subsegmental levels. The interobserver correlations for diagnosis of subsegmental PE with multidetector spiral CT exceed the reproducibility of selective pulmonary angiography. If appropriate equipment is available (multidetector CT), then CT pulmonary angiogram is safe to be used as the first-line imaging investigation for the diagnosis of PE.     

Unusual pulmonary angiographic findings in suspected pulmonary embolism

Pulmonary arteriography is most commonly performed to diagnose pulmonary embolism. A variety of clinical entities, however, may mimic pulmonary embolism both clinically and scintigraphically. Five patients with abnormal pulmonary arteriograms resulting from diseases other than pulmonary embolism are presented. The clinical, radiographic, and pathologic findings and long-term follow-up in these patients are described. Awareness of the angiographic patterns seen in these unusual cases is important in the differential diagnosis of pulmonary thromboembolism.     

Angiography and perfusion pulmonary scintigraphy in pulmonary embolism

Clinical signs suggestive of pulmonary embolism require diagnostic confirmation from complementary scintigraphic and/or angiographic examinations, therapy being adapted to the results obtained. A comparative study of the value of the two techniques was conducted in 20 patients with suspected pulmonary embolism investigated by a perfusion pulmonary scan and selective pulmonary angiography. Results confirmed the diagnostic superiority of angiography, the high percentage of false positives obtained by perfusion scintigraphy alone indicating the need for associated ventilatory function tests.     

CT pulmonary angiography and suspected acute pulmonary embolism

PURPOSE: To evaluate the use and quality of CT pulmonary angiography in our department, and to relate the findings to clinical parameters and diagnoses. MATERIAL AND METHODS: A retrospective study of 324 consecutive patients referred to CT pulmonary angiography with clinically suspected pulmonary embolism (PE). From the medical records we registered clinical parameters, blood gases, D-dimer, risk factors and the results of other relevant imaging studies. RESULTS: 55 patients (17%) had PE detected on CT. 39 had bilateral PE, and 8 patients had isolated peripheral PE. 87% of the examinations showing PE had satisfactory filling of contrast material including the segmental pulmonary arteries, and 60% of the subsegmental arteries. D-dimer test was performed in 209 patients, 85% were positive. A negative D-dimer ruled out PE detected at CT. Dyspnea and concurrent symptoms or detection of deep vein thrombosis (DVT), contraceptive pills and former venous thromboembolism (VTE) were associated with PE. The presence of only one clinical parameter indicated a negative PE diagnosis (p < 0.017), whereas two or more suggested a positive PE diagnosis (p < 0.002). CT also detected various ancillary findings such as consolidation, pleural effusion, nodule or tumor in nearly half of the patients; however, there was no association with the PE diagnosis. CONCLUSION: The quality of CT pulmonary angiography was satisfactory as a first-line imaging of PE. CT also showed additional pathology of importance in the chest. Our study confirmed that a negative D-dimer ruled out clinically suspected VTE.     

Follow-up pulmonary perfusion scintigraphy pulmonary arterial embolization in two cases of familial pulmonary arteriovenous fistula

Follow-up pulmonary perfusion scintigraphy in evaluating pulmonary arterial embolization were assessed by two cases of pulmonary familial arteriovenous fistula. Pulmonary arteriovenous fistula was found for brain abscess in the older brother, and for dyspnea on effort in the younger brother. Pulmonary arterial embolizations were performed. (older brother: 4 times, younger brother: 5 times) Before embolization, pulmonary perfusion scintigram showed pale defect, clear asymmetric perfusion between right and left lung, and clear renal visualization. On the other hand, after the embolization, clear multiple defects agreed with the sites of embolization, and asymmetric pulmonary perfusion and renal visualization disappeared. We conclude that follow-up pulmonary perfusion scintigraphy is useful to evaluate in pulmonary arteriovenous fistula after embolization.     

Quantitative lobar pulmonary perfusion assessment on dual-energy CT pulmonary angiography: applications in pulmonary embolism

To assess quantitative lobar pulmonary perfusion on DECT-PA in patients with and without pulmonary embolism (PE). Our retrospective study included 88 adult patients (mean age 56 ± 19 years; 38 men, 50 women) who underwent DECT-PA (40 PE present; 48 PE absent) on a 384-slice, third-generation, dual-source CT. All DECT-PA examinations were reviewed to record the presence and location of occlusive and non-occlusive PE. Transverse thin (1 mm) DECT images (80/150 kV) were de-identified and exported offline for processing on a stand-alone deep learning–based prototype for automatic lung lobe segmentation and to obtain the mean attenuation numbers (in HU), contrast amount (in mg), and normalized iodine concentration per lung and lobe. The zonal volumes and mean enhancement were obtained from the Lung Analysis™ application. Data were analyzed with receiver operating characteristics (ROC) and analysis of variance (ANOVA). The automatic lung lobe segmentation was accurate in all DECT-PA (88; 100%). Both lobar and zonal perfusions were significantly lower in patients with PE compared with those without PE (p < 0.0001). The mean attenuation numbers, contrast amounts, and normalized iodine concentrations in different lobes were significantly lower in the patients with PE compared with those in the patients without PE (AUC 0.70–0.78; p < 0.0001). Patients with occlusive PE had significantly lower quantitative perfusion compared with those without occlusive PE (p < 0.0001). The deep learning–based prototype enables accurate lung lobe segmentation and assessment of quantitative lobar perfusion from DECT-PA. • Deep learning–based prototype enables accurate lung lobe segmentation and assessment of quantitative lobar perfusion from DECT-PA. • Quantitative lobar perfusion parameters (AUC up to 0.78) have a higher predicting presence of PE on DECT-PA examinations compared with the zonal perfusion parameters (AUC up to 0.72). • The lobar-normalized iodine concentration has the highest AUC for both presence of PE and for differentiating occlusive and non-occlusive PE.     

MR imaging of pulmonary arterial hypertension and pulmonary emboli

Intraluminal signal in the pulmonary arteries on spin-echo, ECG-gated MR images is limited to the diastolic phase of the cardiac cycle in normal subjects. Initial experience has indicated that signal persisting during systole may be characteristic of slow blood flow associated with pulmonary arterial hypertension (PAH) or of thrombotic material secondary to pulmonary embolism. This study analyzes our cumulative experience (31 patients) with multiphasic, double spin-echo MR for assessing PAH and/or suspected pulmonary embolism. In PAH, the abnormal systolic signal showed an intensity increase from first to second echo. This pattern was observed in 92% of PAH patients, including 100% of patients with pulmonary systolic pressures greater than or equal to 80 mm Hg and 60% of patients with pressures less than 80 mm Hg. At any focus in the pulmonary arteries, such signal disappeared at some phase of the cardiac cycle. In patients with pulmonary embolism, signal from thrombus was fixed throughout the cardiac cycle and showed little or no increase in relative intensity change from first- to second-echo image. Using this guideline, MR made six confirmed positive and four confirmed negative diagnoses of proximal pulmonary embolism, while it failed to identify thrombus in the one patient with a peripheral pulmonary embolism. Intraluminal signal in the pulmonary arteries caused by PAH or pulmonary embolism can be differentiated in most instances using multiphasic, double spin-echo, ECG-gated MR. However, at its current stage of development, the procedure does not appear to be useful for the evaluation of peripheral pulmonary embolism.     

胸腔镜肺叶切除术治疗肺良性疾病的临床分析

目的探讨胸腔镜肺叶切除术治疗肺部良性疾病的可行性和临床应用价值。方法回顾我院2010年3月～2012年7月采用胸腔镜肺叶切除术治疗的37例肺良性疾病的临床资料,对手术方式和围术期相关临床指标进行分析。结果37例患者中,全胸腔镜手术28例,胸腔镜辅助小切口手术9例。平均手术时间178(55～275)min;术中出血平均420(30～1300)ml;术后总引流量平均1420(160～4800)ml;术后住院时间平均9.5(4～27)d。全组无围术期死亡,术后并发呼吸衰竭1例,肺持续漏气1例,其余无严重并发症。结论胸腔镜肺叶切除术治疗肺部良性疾病是安全可行的,对于有肺叶切除适应证的肺部良性疾病患者,可以作为主要的手术方式。