Idiopathic, heritable and veno-occlusive pulmonary arterial hypertension in childhood: computed tomography angiography features in the initial assessment of the disease.

BACKGROUND: In children, idiopathic and heritable pulmonary arterial hypertension present echocardiographic and heart catheterization findings similar to findings in pulmonary veno-occlusive disease. OBJECTIVE: To provide a systematic analysis of CT angiography anomalies in children with idiopathic or heritable pulmonary arterial hypertension, or pulmonary veno-occlusive disease. We also sought to identify correlations between CT findings and patients' baseline characteristics. MATERIALS AND METHODS: We retrospectively analyzed CT features of children with idiopathic and heritable pulmonary arterial hypertension or pulmonary veno-occlusive disease and 30 age-matched controls between 2008 and 2014. We compared CT findings and patient characteristics, including gene mutation type, and disease outcome until 2017. RESULTS: The pulmonary arterial hypertension group included idiopathic (n=15) and heritable pulmonary arterial hypertension (n=11) and pulmonary veno-occlusive disease (n=4). Median age was 6.5 years. Children with pulmonary arterial hypertension showed enlargement of pulmonary artery and right cardiac chambers. A threshold for the ratio between the pulmonary artery and the ascending aorta of ≥1.2 had a sensitivity of 90% and a specificity of 100% for pulmonary arterial hypertension. All children with pulmonary veno-occlusive disease had thickened interlobular septa, centrilobular ground-glass opacities, and lymphadenopathy. In children with idiopathic and heritable pulmonary arterial hypertension, presence of intrapulmonary neovessels and enlargement of the right atrium were correlated with higher mean pulmonary artery pressure (P=0.011) and pulmonary vascular resistance (P=0.038), respectively. Mediastinal lymphadenopathy was associated with disease worsening within the first 2 years of follow-up (P=0.024). CONCLUSION: CT angiography could contribute to early diagnosis and prediction of severity in children with pulmonary arterial hypertension.

Non-invasive assessment of congenital pulmonary vein stenosis in children using cardiac-non-gated CT with 64-slice technology.

BACKGROUND: Management of congenital pulmonary vein stenosis is a diagnostic challenge. Echocardiography may be insufficient and thus cardiac catheterization remains the reference standard in this setting. The aim of the study was to investigate the accuracy of cardiac-non-gated CT using 64-slice technology in detecting congenital pulmonary vein stenosis in children. MATERIALS AND METHODS: CT examinations were consecutively performed from May 2005 to December 2006 in 13 children aged 1.5-12 months (median 5 months) for suspected congenital pulmonary vein stenosis. Cardiac-non-gated CT acquisitions were performed after the peripheral injection of contrast agent. Pulmonary veins were evaluated for their pattern of connectivity from the lung to the left atrium and for the presence of stenosis. CT findings of pulmonary vein stenosis were compared with combined findings available from echocardiography, catheterization and surgery. RESULTS: Pulmonary veins from the right lung (n=29) and left lung (n=26) were evaluated as separate structures (N=55). Of the 55 structures, 32 had surgical and/or catheterization data and 45 had echocardiography for comparison. CT visualized 100% (55/55) of the investigated structures, while echocardiography visualized 82% (45/55). In the 13 subjects CT identified 10 stenotic pulmonary veins. CT confirmed the echocardiography suspicion of pulmonary vein stenosis in 100% (7/7) and established a new diagnosis in 3 other patients. CT agreed with surgery/catheterization in 100% (10/10) of the available comparisons. CONCLUSION: Cardiac-non-gated CT assessed the pulmonary veins more completely than echocardiography and should be considered as a viable alternative for invasive pulmonary venography for detecting pulmonary vein stenosis in children.

Assessment of intra- and interobserver variability of pulmonary vein measurements from CT angiography.

RATIONALE AND OBJECTIVES: Pulmonary vein (PV) stenosis is a common complication after radiofrequency ablation for atrial fibrillation. This study investigated the intra- and interobserver variability and precision of PV ostial measurements from three-dimensional computed tomography angiography. MATERIALS AND METHODS: Four observers measured the maximum and minimum diameters, as well as area, of the four PVs of seven patients who underwent a three-dimensional computed tomography scan before radiofrequency ablation. Each observer performed two sets of measurements. The intra- and interobserver variability of the measurements was calculated using analysis of variance. RESULTS: Intraobserver variability was approximately two times lower than interobserver variability in measurements of diameter and area. The standard error of the measurement (SEM), SEM(intra) and SEM(inter), were lower for the mean diameter than the maximum diameter. The minimum detectable changes in diameters, DeltaD(intra) and DeltaD(inter), and area, DeltaA(intra) and DeltaA(inter), demonstrated the same statistical trend as the corresponding SEM for each of the four veins. Both DeltaD(intra) and DeltaD(inter) and DeltaA(intra) and DeltaA(inter) were smaller than the corresponding lower bounds of the 95% confidence interval for 50% diameter reduction and 75% area reduction. The direct results of DeltaA(intra) and DeltaA(inter) for each of the four veins were consistently less than DeltaA's calculated from the corresponding DeltaD(intra) and DeltaD(inter). CONCLUSION: PV ostial measurements are less variable when made by a single observer than by multiple observers, and mean diameter measurements are more precise than a single, maximum diameter measurement. Both diameter and area measurements are capable of quantifying the mild PV stenosis. Furthermore, area can be measured with greater precision than mean diameter and should be used in PV ostium caliber determination.

Simultaneous assessment of right ventricular function and hypertrophy by Tc-99m MIBI.

PURPOSE: Tc-99m MIBI allows the simultaneous performance of cardiac blood pool scintigraphy and myocardial SPECT. The authors performed studies to determine whether right ventricular function and hypertrophy can be evaluated simultaneously using Tc-99m MIBI in patients with right heart disease. METHODS: Using right heart catheterization, several parameters of pulmonary circulation were measured, including right ventricular ejection fraction, in 23 patients with chronic pulmonary disease and pulmonary vascular disease. Within 1 week, right heart blood pool scintigraphy was performed using the first-pass method using Tc-99m MIBI. The right ventricular ejection fraction calculated from right heart blood pool scintigraphy was compared with that measured using right heart catheterization. Myocardial SPECT was performed 1 hour after right heart blood pool scintigraphy. On the short axis images, which allowed optimal visualization of the right ventricle, the right and left ventricular free walls were established as regions of interest. Myocardial wall counts were determined. The right ventricular uptake: left ventricular uptake ratio was calculated to study the relation of that ratio to mean pulmonary artery pressure and total pulmonary resistance. RESULTS: A significant correlation was observed between the right ventricular ejection fraction calculated on right heart catheterization and that calculated on right heart blood pool scintigraphy. The right ventricular uptake:left ventricular uptake ratio correlated positively with pulmonary artery pressure and total pulmonary resistance. CONCLUSION: These results suggest that Tc-99m MIBI allows simultaneous noninvasive evaluation of cardiac function and structure, which previously was considered impossible in patients with right heart disease.