Severity assessment of acute pulmonary embolism: evaluation using helical CT

The objective was to evaluate the helical CT (HCT) criteria that could indicate severe pulmonary embolism (PE). In a retrospective study, 81 patients (mean age 62 years) with clinical suspicion of PE explored by HCT were studied. The patients were separated into three different groups according to clinical severity and treatment decisions: group SPE included patients with severe PE based on clinical data who were treated by fibrinolysis or embolectomy (n=20); group NSPE included patients with non-severe PE who received heparin (n=30); and group WPE included patients without PE (n=31). For each patient we calculated a vascular obstruction index based on the site of obstruction and the degree of occlusion in the pulmonary artery. We noted the HCT signs, i.e., cardiac and pulmonary artery dimensions, that could indicate acute cor pulmonale. According to multivariate analysis, factors significantly correlated with the severity of PE were: the vascular obstruction index (group SPE: 54%; group NSPE: 24%; p<0.001); the maximum minor axis of the left ventricle (group SPE: 30.2 mm; group NSPE: 40.4 mm; p<0.001); the diameter of the central pulmonary artery (group SPE: 32.4 mm; group NSPE: 28.3 mm; p<0.001); the maximum minor axis of the right ventricle (group SPE: 47.5 mm; group NSPE: 42.7 mm; p=0.029); the right ventricle/left ventricle minor axis ratio (group SPE: 1.63; group NSPE: 1.09; p<0.0001). Our data suggest that hemodynamic severity of PE can be assessed on HCT scans by measuring four main criteria: the vascular obstruction index; the minimum diameter of the left ventricle; the RV:LV ratio; and the diameter of the central pulmonary artery.     

螺旋CT肺动脉造影对肺栓塞的诊断

目的：评价螺旋CT及其肺动脉造影诊断肺动脉栓塞（PE）的价值。方法：回顾性分析12例PE患,均行螺旋CT容积扫描,并在工作站进行图像后处理,获得肺动脉多平面重建图像及三维立体图像。结果：对12例196支肺动脉分支进行分析,受累率为46.4%;栓子发生在主肺动脉、左右肺动脉干及叶段肺动脉。多平面重建图像上表现为充盈对比剂血管内有充盈缺损区,或其远侧方无对比剂充填区。肺动脉成像示,主干血管内可见充盈缺损影,或呈截断状影;叶栓塞或段栓塞亦呈突然“截断状”,其远侧方肺动脉分支不显影或呈纤维状。结论：螺旋CT肺动脉造影不仅可以获得轴位图像,而且可以获得立体图像,可多轴向旋转观察PE部位,是诊断叶或段以上PE可靠而直观的检查方法。     

Value of negative spiral CT angiography in patients with suspected acute PE: analysis of PE occurrence and outcome

The aim of this study was to analyze pulmonary embolism (PE) occurrence and retrospective clinical outcome in patients with clinically suspected acute PE and a negative spiral CT angiography (SCTA) of the pulmonary arteries. Within a 35-month period, 485 consecutive patients with clinical symptoms of acute PE underwent SCTA of the pulmonary arteries. Patients with a negative SCTA and without anticoagulation treatment were followed-up and formed the study group. Patient outcome and recurrence of PE was evaluated retrospectively during a period of 6 months after the initial SCTA, and included a review of computerized patient records, and interviews with physicians and patients. Patients were asked to fill out a questionnaire concerning all relevant questions about their medical history and clinical course during the follow-up period. Special attention was focused on symptoms indicating recurrent PE, as well as later confirmation and therapy of PE. Of the 485 patients, 325 patients (67%) had a negative scan, 134 (27.6%) had radiological signs of PE, and 26 (5.4%) had an indeterminant result. Of 325 patients with a negative scan, 269 (83%) were available for follow-up. The main reasons for loss to follow-up were change of address, name, or phone number, or non-resident patients who left abroad. Of 269 patients available for follow-up, 49 patients (18.2% of 269) received anticoagulant treatment because of prior or recent deep venous thrombosis (32.6%) or a history of PE (34.7%), cardiovascular disease (18.4%), high clinical probability (8.2%), positive ventilation–perfusion scan (4.2%), and elevated D-dimer test (2%). The remaining 220 patients, who did not receive anticoagulant medication, formed the study group. Of this study group, 1 patient died from myocardial infarction 6 weeks after the initial SCTA, and the postmortem examination also detected multiple peripheral emboli in both lungs (p=0.45%; 0.01–2.5, 95% confidence interval). The PE did not occur in any other patient. In patients with suspected PE and negative SCTA without anticoagulant therapy, the risk of recurrent PE in this study was less than 1% and similar to that in patients after a negative pulmonary angiogram. Therefore, we conclude that patients can be managed safely without anticoagulation therapy; however, this approach may not be appropriate for critically ill patients and those with persistent high clinical suspicion of acute PE.     

Clinically suspected pulmonary embolism: is it safe to withhold anticoagulation after a negative spiral CT?

The goal of this study was 3-month clinical outcome in non-anticoagulated patients with clinically suspected acute pulmonary embolism (PE) following a negative spiral CT. During a 6-month period 305 patients underwent spiral CT, of whom only 8 also had a lung scintigraphy. In patients with a final CT report read as not positive for acute PE, all hospital records and answers to a patient questionnaire were analyzed for episodes of venous thrombembolism (VTE). Acute PE was diagnosed at spiral CT in 61 patients (20 %). Twenty-six of the remaining 244 patients were excluded from further analysis because of (a) long-term anticoagulation due to symptomatic acute deep venous thrombosis (n = 5), clinically diagnosed acute PE (n = 2), chronic recurrent VTE (n = 4), and cardiac disorders (n = 5); and (b) a normal perfusion scintigram (n = 4) or a negative pulmonary arteriogram (n = 6). Three patients were lost to follow-up. Among the remaining 215 patients only 10 had undergone a negative lower extremity venous study. Sixteen patients (7 %) died during the follow-up period, 6 of whom underwent autopsy. Venous thrombembolism was diagnosed in three of the 215 patients (1.4 %, 95 % confidence limits: 0.5–4.0 %), one causing the patient's death. Two patients had advanced thoracic malignancies and the third severe chronic obstructive pulmonary disease (84 years old). A negative spiral CT may be able to exclude clinically significant acute PE with the same accuracy as a normal lung scintigraphy or a negative pulmonary arteriography. Received: 8 February 2000 Revised: 18 May 2000 Accepted: 22 May 2000     

Comparison of doses for pulmonary embolism detection with helical CT and pulmonary angiography

The objective of this study was to compare the radiation exposure delivered by helical CT and pulmonary angiography (PA) for the detection of pulmonary embolism (PE), with an anthropomorphic phantom. A preliminary survey defined a representative standard procedure for helical CT and PA (n=148) by choosing the exposure settings most frequently used. Then, radiation doses were measured with thermoluminescent dosimeters TLD 100 (Lif) introduced into the depth of an anthropomorphic phantom. Average doses were approximately five times smaller with helical CT than with PA (6.4±1.5 and 28±7.6 mGy, respectively). The most important doses were abreast the pulmonary apex for CT, and abreast the pulmonary arteries for PA. Compared with PA, helical CT dose distribution was relatively uniform (10–13 mGy). Finally, concerning abdomen and pelvis, doses were more important for PA than for CT scan (0.06–2.86 and 0.2–11.5 mGy, respectively). For the diagnostics of PE, radiation exposure is five times smaller with helical CT than with pulmonary angiography.     

Safety and Efficacy of Acute Pulmonary Embolism Treated via Large-Bore Aspiration Mechanical Thrombectomy Using the Inari FlowTriever Device

PurposeTo report initial experience with safety and efficacy in the treatment of pulmonary embolism (PE) using the FlowTriever device.Materials and MethodsA single-center retrospective study was performed in all patients with acute central PE treated using the FlowTriever device between March 2018 and March 2019. A total of 46 patients were identified (massive = 8; submassive = 38), all with right ventricular (RV) strain and 26% with thrombolytic contraindications. Technical success (according to SIR reporting guidelines) and clinical success (defined as mean pulmonary artery pressure intraprocedural improvement) are reported, as are major device and procedure-related complications within 30 days after discharge.ResultsTechnical success was achieved in 100% of cases (n = 46). Average mean pulmonary artery pressure improved significantly from before to after the procedure for the total population (33.9 ± 8.9 mm Hg before, 27.0 ± 9.0 mm Hg after; P < .0001; 95% confidence interval [CI], 5.0–8.8), submassive cohort (34.7 ± 9.1 mm Hg before, 27.4 ± 9.2 mm Hg after; P < .0001; 95% CI, 5.2–9.5) and massive cohort (30.4 ± 6.9 mm Hg before, 25.4 ± 8.2 mm Hg after; P < .05; 95% CI:0.4–9.6). Intraprocedural reduction in mean pulmonary artery pressure was achieved in 88% (n = 37 of 42). A total of 100% of patients (n = 46 of 46) survived to hospital discharge. In total, 71% of patients (n = 27 of 38) experienced intraprocedural reduction in supplemental oxygen requirements. Two major adverse events (4.6%) included hemoptysis requiring intubation, and procedure-related blood loss requiring transfusion. No delayed procedure-related complications or deaths occurred within 30 days of hospital discharge.ConclusionsInitial clinical experience using the FlowTriever to perform mechanical thrombectomy showed encouraging trends with respect to safety and efficacy for the treatment of acute central, massive, and submassive pulmonary embolism.     

Computed tomography pulmonary embolism index for the assessment of survival in patients with pulmonary embolism

This study was an analysis of the correlation between pulmonary embolism (PE) and patient survival. Among 694 consecutive patients referred to our institution with clinical suspicion of acute PE who underwent CT pulmonary angiography, 188 patients comprised the study group: 87 women (46.3%, median age: 60.7; age range: 19–88 years) and 101 men (53.7%, median age: 66.9; age range: 21–97 years). PE was assessed by two radiologist who were blinded to the results from the follow-up. A PE index was derived for each set of images on the basis of the embolus size and location. Results were analyzed using logistic regression, and correlation with risk factors and patient outcome (survival or death) was calculated. We observed no significant correlation between the CTPE index and patient outcome (p = 0.703). The test of logistic regression with the sum of heart and liver disease or presence of cancer was significantly (p< 0.05) correlated with PE and overall patient outcome. Interobserver agreement showed a significant correlation rate for the assessment of the PE index (0.993; p< 0.001). In our study the CT PE index did not translate into patient outcome. Prospective larger scale studies are needed to confirm the predictive value of the index and refine the index criteria. This work was supported by the European Commission Leonardo da Vinci grant.     

多层螺旋CT肺动脉成像评价急性肺栓塞严重性的初步研究

目的:探讨多层螺旋CT肺动脉成像(CTPA)在评价肺栓塞(PE)严重性方面的价值。方法:23例急性PE患者行16层螺旋CT肺动脉和下肢静脉血管成像。根据超声心动图的检查结果,将患者分为右室劳损组(A组,7例)和无右室劳损组(B组,16例)。在CTPA心腔短轴位图像上测量右室最大横径(RVMMA)、左室最大横径(LVMMA)、主肺动脉(PA)直径、升主动脉(AO)直径,观察室间隔移位、下腔静脉对比剂反流情况,并计算RVMMA/LVMMA和PA/AO值及肺动脉阻塞指数。结果:A组与B组比较,差异有显著性意义的参数包括肺动脉阻塞指数(分别为46.79%、25.31%,P=0.024),RVMMA(分别为4.9和3.51cm,P<0.001),LVMMA(分别为3.34和4.07cm,P=0.046),RVMMA/LVMMA(分别为1.56、0.88,P=0.002),主肺动脉直径(分别为3.31和2.67cm,P=0.01),PA/AO(分别为1.03、0.75,P=0.011),室间隔移位比(分别为4/7、1/16,P=0.017)。以肺动脉阻塞指数为47%作为阈值时,诊断右心室劳损的敏感度为57%,特异度为75%;以RVMMA/LVMMA为1.4作为阈值,诊断右心室劳损的敏感度为71%,特异度为100%。结论:CTPA不仅可以诊断PE,并且可以提示急性PE的严重性。     

螺旋CT在肺动脉栓塞诊断中的价值

目的:评价螺旋CT在诊断肺动脉栓塞中的作用。方法:16例肺动脉栓塞患者行螺旋CT肺动脉造影 (SCTA)检查,层厚3mm,扫描时间0.8s,对比剂注射速度3.5ml/s,总量100ml,扫描延迟时间15s。结果:16例 共644支,其中134支肺动脉及分支显示了栓塞,占20.8%。228支肺段肺动脉中,有56支显示肺动脉栓塞,占分 析肺动脉支的24.5%。204支亚段肺动脉中37支显示肺动脉栓塞,占分析肺动脉支15.4%。肺动脉栓塞的CT形 态:①直接征象为不同程度的肺动脉分支内充盈缺损。中心型充盈缺损17支,偏心型充盈缺损44支,附壁血栓型 34支,完全阻塞型39支。②间接征象胸膜下肺梗死灶,内乳动脉一侧增粗,肺纹理稀少,胸水,肺动脉高压。结论: 螺旋CT肺动脉造影是诊断肺动脉栓塞的快速、有效、无创伤的诊断方法。     

Non-severe pulmonary embolism: Prognostic CT findings

The goal of this study was to retrospectively evaluate CT cardiovascular parameters and pulmonary artery clot load score as predictors of 3-month mortality in patients with clinically non-severe pulmonary embolism (PE). We included 226 CT positive for PE in hemodynamically stable patients (112 women; mean age 67.1 years ±16.9). CT were independently reviewed by two observers. Results were compared with occurrence of death within 3 months using Cox regression. Twenty-four (10.6%) patients died, for whom 9 were considered to be due to PE. Interobserver agreement was moderate for the shape of interventricular septum (κ = 0.41), and for the ratio between the diameters of right and left ventricle (RV/LV) (κ = 0.76). Observers found no association between interventricular septum shape and death. A RV/LV diameter ratio >1 was predictive of death (OR, 3.83; p < 0.01) only when we also took into account the value of the embolic burden (<40%). In a multivariate model, CT cardiovascular parameters were not associated with death. Concomitant lower limb DVT and comorbid conditions were important predictors of death. In clinically non-severe PE, a RV/LV diameter ratio >1 is predictive of death when the embolic burden is low (<40%).     

Comparison of Ultrasound-Accelerated versus Pigtail Catheter–Directed Thrombolysis for the Treatment of Acute Massive and Submassive Pulmonary Embolism

Purpose

To compare the technical and clinical effectiveness of ultrasound-accelerated endovascular thrombolysis (USAT) versus pigtail catheter–directed thrombolysis (PCDT) for the treatment of acute pulmonary embolism (PE).

Massive Pulmonary Embolism: Treatment with the Rotarex Thrombectomy System

This study was designed to evaluate the efficacy and safety of percutaneous mechanical thrombectomy (PMT) for acute massive pulmonary embolism (PE). Fourteen patients (8 men, 6 women) with a mean age of 55.4 (range, 38?C71) years with acute massive PE were initially diagnosed by computed tomography (CT) and confirmed by pulmonary angiography. All patients presented with acute PE symptoms and hemodynamic compromise. Each patient was treated with Straub Rotarex thrombectomy device and five patients received additional thrombolysis. Technique success and clinical improvement were achieved in all patients without major complications. The mean pulmonary artery pressure (PAP) decreased from 37.6?±?6.6 to 29?±?6.4?mmHg (P?<?0.01) after PMT. Partial arterial pressures of O₂ (PaO₂) increased from 61.1?±?9.2 to 88?±?5.1?mmHg (P?<?0.01). The Miller index was 0.67?±?0.11 and 0.37?±?0.13 (P?<?0.01), respectively, before and after PMT (P?<?0.01). Eleven patients had no recurrence of PE on a mean follow-up of 28.3?months, whereas the other three patients were lost to follow-up. The preliminary experience in our series suggests that the Straub Rotarex thrombectomy device, which has been utilized in peripheral arteries, also is useful for the treatment of acute massive PE.     

Large-Bore Aspiration Thrombectomy versus Catheter-Directed Thrombolysis for Acute Pulmonary Embolism: A Propensity Score–Matched Comparison

PurposeTo compare effectiveness and safety of large-bore aspiration thrombectomy (LBAT) with catheter-directed thrombolysis (CDT) for treatment of acute massive and submassive pulmonary embolism (PE).Materials and MethodsThis retrospective review included patients with acute PE treated with LBAT or CDT using tissue plasminogen activator (tPA) between December 2009 and May 2020. A propensity score based on Pulmonary Embolism Severity Index class and PE severity (massive vs submassive) was calculated, and 26 LBAT cases (age 60.2 y ± 17.1, 14/26 women) were matched with 26 CDT cases (age 59.7 y ± 14.2, 14/26 women).ResultsThe CDT group had 22.1 mg ± 8.1 tPA infused over 21.2 h ± 6.6. Both groups demonstrated similar initial and final systolic pulmonary artery pressure (PAP) (LBAT: 54.5 mm Hg ± 12.9 vs CDT: 54.5 mm Hg ± 16.3, P = .8, and LBAT: 42.5 mm Hg ± 14.1 vs CDT: 42.6 mm Hg ± 12.1, P = .8, respectively) and similar reductions in heart rate (LBAT: −5.4 beats/min ± 19.2 vs CDT: −9.6 beats/min ± 15.8, P = .4). CDT demonstrated a higher reduction in Miller score (−10.1 ± 3.9 vs −7.5 ± 3.8, P = .02). LBAT resulted in 1 minor hemorrhagic complication and 2 procedure-related mortalities, and CDT resulted in 1 minor and 1 major hemorrhagic complication.ConclusionsLBAT and CDT resulted in similar reductions of PAP and heart rate when used to treat acute PE. CDT reduced thrombus burden to a greater degree. Although hemorrhagic complications rates were not significantly different, the LBAT group demonstrated a higher rate of procedure-related mortality. Larger studies are needed to compare the safety of these techniques.     

MRI for short-term follow-up of acute pulmonary embolism. Assessment of thrombus appearance and pulmonary perfusion: a feasibility study

Tha aim of this study was to demonstrate the feasibility of MRI for short-term follow-up examinations in patients with acute pulmonary embolism (PE), and to assess temporal changes of pulmonary perfusion and thrombus characteristics that may be helpful in determining thrombus age. Thirty-three patients (15 female, 18 male, mean age 59.4 years) with acute PE were examined initially and 1 week later using both 16-row computed tomography (CT) and MRI with magnetic resonance angiography (MRA), real-time MRI and magnetic resonance (MR) pulmonary perfusion imaging. MRA and MR pulmonary perfusion used contrast-enhanced 3D flash sequences, and real-time MRI used true fast imaging with steady-state precession sequences (repetition time/echo time 3.1/1.5, bandwidth 975 Hz, 256 matrix size, acquisition time 0.4 s per image) in three orthogonal planes. Follow-up examinations were feasible for all patients. Diagnosis of PE was concordant between MRI and CT in all patients. The signal intensity of embolic material increased after 1 week for real-time MRI [132±5 vs. 232±22 (standard error of the mean), p<0.001], but not significantly for MRA. MR pulmonary perfusion of areas affected by PE increased (area under the curve initially 9.6±7.4, at follow-up 40.7±7.6, p<0.001). A decreasing time-to-peak in normal lung areas (15.7±0.96 and 13.2±0.55, respectively, p<0.05) indicated systemic circulatory effects of PE, and subsiding pulmonary artery obstruction improved arterial inflow for the entire lung. Follow-up examinations of patients with acute PE are feasible with MRI, and a relation between thrombus appearance and thrombus age can be implied.     

Focal airtrapping at expiratory high-resolution CT: comparison with pulmonary function tests

This study was undertaken to determine prevalence, extent, and severity of focal airtrapping at expiratory high-resolution CT, and to compare focal airtrapping with age, gender, pulmonary function tests, and blood gas analysis. Two-hundred seventeen patients with and without pulmonary disease underwent paired inspiratory/expiratory high-resolution CT. Six scan pairs with corresponding scan levels were visually assessed for focal – not diffuse – airtrapping using a four-point scale. Pulmonary function tests and blood gas analysis were available for correlation in all patients (mean interval 5 days). Focal airtrapping with lower lung predominance was observed in 80 % of patients. Twenty-six of 26 patients with restrictive lung function impairment exhibited focal airtrapping (mean score 2.4), whereas only 72 of 98 (74 %) patients with obstruction did (mean score 1.5; p < 0.05). Fifty-eight of 70 (83 %) patients with normal lung function (mean score 1.8) and 19 of 23 (83 %) patients with mixed impairment (mean score 1.8) had focal airtrapping. Focal airtrapping showed negative correlations with static lung volumes (–0.27 to –0.37; p < 0.001) in all patients and moderate positive correlations with dynamic parameters (0.3–0.4; p < 0.001) in patients with obstruction. No significant correlations were found with age, gender, and blood gas analysis. Visual assessment of focal – not diffuse – airtrapping at expiratory high-resolution CT does not correlate with physiological evidence of obstruction as derived from pulmonary function tests since the perception of focal airtrapping requires an adequate expiratory increase in lung density. Received: 11 February 2000; Revised: 8 June 2000; Accepted: 9 June 2000     

CT阻塞指数对肺栓塞的评价及其与D-二聚体相关性分析

目的：探讨肺动脉CT阻塞指数对肺栓塞(PE)高危性的评价及其与D-二聚体之间的关系。方法收集经 CT肺动脉成像(CTPA)及D-二聚体检查的125例PE病例。将其分为高危PE组和非高危PE组,比较分析2组在 CT阻塞指数、D-二聚体、主肺动脉直径间的差异,以及肺动脉 CT 阻塞指数与 D-二聚体、主肺动脉直径之间的相关性(Spearman相关性评价)。结果高危PE组的CT阻塞指数明显高于非高危PE组(P=0.000),高危PE组主肺动脉直径较非高危PE组增粗,差异有统计学意义(P=0.000),而高危PE组和非高危PE组D-二聚体差异无统计学意义(P=0.103)。CT阻塞指数与D-二聚体无相关性(P=0.71)。结论血浆D-二聚体指标可以提示PE,不能评价PE的高危性;肺动脉CT阻塞指数在一定程度上可以反映PE的严重性,其与 D-二聚体间无相关性。     

多层螺旋CT对肺栓塞影像表现及与其严重性关系的评价

目的 评价多层螺旋CT肺栓塞影像表现及与其严重性的关系.资料与方法 回顾性分析104例临床诊断肺栓塞患者的临床及影像学资料,测量心血管参数:主肺动脉直径、右心室短轴最大径(RVMSA)、左心室短轴最大径(LVMSA)及RVMSA/LVMSA比值,计算CT肺动脉成像(CTPA)阻塞指数,评价CTPA上栓子的形态和与双能量CT(DECT)上灌注缺损的关系及CTPA阻塞指数与心血管测量参数的关系.结果 104例中,32例因图像丢失(n=10)、CTPA图像欠佳,不满足测量要求(n=9)或未行CTPA检查(n=13),故只对72例患者的影像学资料进行分析评价.完全闭塞型肺栓塞DECT表现为整个肺叶灌注降低或某个肺段灌注缺损,部分闭塞型DECT表现为灌注降低或正常.CT阻塞指数与心血管测量参数具有一定的相关性(P<0.05),以CT阻塞指数与RVMSA/LVMSA比值相关性最高(r=0.519,P<0.001).结论 肺灌注异常与否取决于肺动脉栓塞的程度;CT肺动脉阻塞指数可用于评价肺栓塞的严重性.     

Can helical CT replace scintigraphy in the diagnostic process in suspected pulmonary embolism? A retrolective-prolective cohort study focusing on total diagnostic yield

The aim of our study was to compare the diagnostic value of helical CT vs that of ventilation–perfusion (V/Q) scintigraphy as a first-line test in a diagnostic strategy in patients suspected of pulmonary embolism (PE). In a retrolective–prolective cohort study we tested the accuracy of helical CT vs V/Q scintigraphy in 123 patients suspected of PE. A diagnostic panel was asked to formulate the presumptive diagnosis on the presence or absence of PE, or of alternative disease by using two competing diagnostic strategies. These consisted of the patient history, laboratory tests and chest X-ray (together baseline tests) in combination with either helical CT or V/Q scintigraphy (CT strategy and V/Q strategy, respectively). The results were compared with the final diagnosis in each patient that was established from various reference tests (which included V/Q scintigraphy, pulmonary angiography and clinical follow-up). The CT and V/Q strategies were compared with regard to the accuracy for PE, for alternative diseases and with regard to the proportion of conclusive diagnoses that were made. The CT strategy was more accurate than the V/Q strategy for detecting or excluding PE. Sensitivity and specificity were 49 and 74 % for the V/Q strategy and 75 and 90 % for the CT strategy, respectively (P = 0.01). The CT strategy provided a conclusive diagnosis in a significantly larger proportion of patients than the V/Q strategy, 92 vs 72 % (P < 0.001). The CT strategy detected more alternative diagnosis than the V/Q strategy, 93 vs 51 %, respectively (P < 0.001). Helical CT seems more useful than V/Q scintigraphy as a first-line test in patients suspected of PE. Received 9 June 1997; Accepted 14 July 1997     

Does pregnancy affect vascular enhancement in patients undergoing CT pulmonary angiography?

The aim of this study was to evaluate whether pregnancy affects contrast enhancement within the pulmonary arteries during computed tomography pulmonary angiography (CTPA). This was a retrospective analysis of the CTPA examinations of 16 pregnant and 16 non-pregnant female patients, suspected of having an acute pulmonary embolus (PE), during the same time period. Pulmonary vascular enhancement was evaluated by measuring the CT density within the pulmonary arteries. In a blinded evaluation, subjective grading of contrast enhancement within the pulmonary arteries was also performed. There was a significant difference in arterial enhancement between the two groups, with pregnant patients having a mean pulmonary arterial density 112 HU less than patients in the control group [mean attenuation of 259.79 ± 59.31 HU in pregnant patients versus 371.88 ± 60.63 HU in non-pregnant patients (p < 0.001)]. The mean subjective pulmonary arterial enhancement score in the pregnant group was 8.19 ± 2.51 versus 13.69 ± 3.07 in the control group (p < 0.001). Pregnant women undergoing CTPA have significantly decreased pulmonary arterial enhancement compared to non-pregnant patients, probably due to the increase in cardiac output in pregnancy. We may need to reconsider how we perform CTPA in this group in order to ensure adequate opacification for diagnosis.     

Utility of coaxial technique for renal angioplasty in patients with a difficult-to-cross stenosis

The aim of this study was to evaluate the feasibility of coaxial approach in difficult-to-cross lesions in patients with failed percutaneous transluminal renal angioplasty by conventional over-the-wire exchange technique. Twelve stenoses in 10 patients (six women and four men; age range 19 ± 7 years) with uncontrolled hypertension were treated by this method. The stenosis was caused by nonspecific aortoarteritis in 8 patients and fibromuscular dysplasia in 2 patients. It was ostial in seven and post-ostial in five vessels. Conventional exchange technique was unsuccessful in all of them. All procedures were done by femoral route. Technical success was seen in 11 (92 %), without complication. The stenosis improved from 90 ± 2.1 % (range 80–100 %) to 6 ± 7 % (range 0–20 %), blood pressure decreased from 198 ± 12.3 mm Hg (range 180–220 mm Hg)/130 ± 6.7 mm Hg (range 120–140 mm Hg) to 119 ± 5.7 mm Hg (range 110–130 mm Hg)/83 ± 3.9 mm Hg (range 80–90 mm Hg), and number of drug treatments for hypertension fell from 3.6 ± 0.52 (range 3–4) to 1 ± 0.94 (range 0–3; p < 0.01). Percutaneous transluminal renal angioplasty resulted in “cure” in 3 patients and “improvement” in 7 patients. Follow-up period was 3–21 months (mean 6.4 months). No restenosis was detected. Coaxial approach is safe and effective in treating difficult-to-cross lesions in which renal angioplasty by conventional exchange technique is unsuccessful. Received: 7 May 1998; Revision received: 10 November 1998; Accepted: 25 November 1998