Quantitative Assessment of Ventricular Septal Contour for Estimation of Right Ventricular Pressure.

BACKGROUND: Qualitative assessment of ventricular septal flattening is commonly used in pediatric patients with pulmonary hypertension (PH) who lack adequate tricuspid regurgitation (TR) Doppler signal. We sought to determine the relation between quantitative measures of septal flattening including the eccentricity index (EIs) and a novel marker, the septal flattening angle (SFA) with right ventricular systolic pressure (RVSP). METHODS: Subjects (≤18 years) with an anatomically normal heart, an adequate TR signal to obtain a peak velocity, and a simultaneous systemic systolic blood pressure (SBP) was included. RVSP was derived using TR gradient. Eccentricity index (EIs) and the SFA in systole were measured offline and correlated with RVSP/SBP. RESULTS: Of the 108 subjects, RVSP/SBP was < 50% in 77 and ≥ 50% in 31. In those with RVSP/SBP ≥50%, the median SFA was significantly lower (7.4° vs. 22°, p < 0.0001), and the median EIs was higher (1.61 vs. 1.07, p < 0.0001). SFA and EIs had a significant correlation with RVSP/SBP (rs = -0.70 and 0.61, respectively). Area under the curve was higher for SFA compared to EIs (0.92 and 0.85, respectively). The sensitivity and specificity of SFA for predicting an RVSP/SBP ≥ 50% using a cut point of 16° was 84% and 95% and for an EIs cut point of 1.35 was 74.2% and 96.1%, respectively. CONCLUSION: Septal flattening angle and EIs are quantitative measures of ventricular septal flattening that correlate well with RVSP/SBP and should be considered more routinely in clinical practice, especially in patients with inadequate TR Doppler signal.

Echocardiography of the tricuspid and pulmonary valve in children.

Diseases of the tricuspid and pulmonary valve are common in childhood. These include congenital anomalies, acquired lesions, and secondary valve compromise due to left heart disease. A comprehensive and methodical approach to the echocardiographic assessment of these diseases of the tricuspid and pulmonary valve is necessary for best care of children with these conditions.

Massive hemoptysis in a post-Fontan procedure patient.

Aortopulmonary collateral vessels (AP collaterals) are frequently seen in patients with cyanotic heart disease. However, massive hemoptysis leading to life-threatening hemorrhage is rare. In this case, we present a 7-year-old girl who presented to the pediatric emergency department with massive hemoptysis secondary to AP collateral hemorrhage. We were able to control her hemoptysis initially through calming techniques, but the patient eventually went on to have 2 cardiac catherization procedures, during which coiling of many AP collateral vessels was performed.

Effective radiation dose in computed tomographic angiography of the chest and diagnostic cardiac catheterization in pediatric patients.

Computed tomographic angiography (CTA) and cardiac catheterization are useful adjuncts to echocardiography for delineating cardiovascular anatomy in pediatric patients. These studies require ionizing radiation, and it is paramount to understand the amount of radiation pediatric patients receive when these tests are performed. Modern dosimetry methods facilitate the conversion of radiation doses of varying units into an effective radiation dose. To compare the effective radiation dose between nongated CTA of the chest and diagnostic cardiac catheterization in pediatric patients. This is a retrospective cohort study of patients of patients who underwent either nongated CTA of the chest or diagnostic cardiac catheterization between July 2009 and April 2010. Fifty patients were included in each group as consecutive samples at a single tertiary care center. An effective radiation dose (mSv) was formulated using conversion factors for each group. The median effective dose (ED) for the CTA group was 0.74 mSv compared with 10.8 mSv for the catheterization group (p < 0.0001). The median ED for children <1 year of age in the CTA group was 0.76 mSv compared with 13.4 mSv for the catheterization group (p < 0.0001). Nongated CTA of the chest exposes children to 15 times less radiation than diagnostic cardiac catheterization. Unless hemodynamic data are necessary, CTA of the chest should be considered in lieu of diagnostic cardiac catheterization in patients with known or presumed cardiac disease who need additional imaging beyond echocardiography.

Murine S factors for liver, spleen, and kidney.

UNLABELLED: Preclinical evaluation of new radiopharmaceuticals is performed in animal systems before testing is started in humans. These studies, often performed in murine or other rodent models, are important in understanding the relationship between absorbed dose and response, which can be translated to preclinical results for humans. In performing such calculations, either electrons are assumed to deposit all of their energy locally or idealized models of mouse anatomy are used to determine absorbed fractions. Photon contributions are generally considered negligible. To improve the accuracy of such absorbed dose calculations, mouse-specific S factors for (131)I, (153)Sm, (32)P, (188)Re, and (90)Y have been generated, and the photon and electron portions have been tabulated separately. Absorbed fractions for 5 monoenergetic electrons, ranging in energy from 0.5 to 2 MeV, are also provided. METHODS: Female athymic mouse MR images were obtained on a 4.7-T MRI device. Fifteen T1-weighted, 1.5-mm-thick slices (0.5-mm gap) were collected. Using a previously developed software package, 3-dimensional Internal Dosimetry (3D-ID), organ contours were drawn to obtain a 3-dimensional representation of liver, kidneys, and spleen. Using a point-kernel convolution, the mean absorbed dose to each organ from the individual contributions of each source organ were calculated. S factor equivalent values were obtained by assuming a uniform distribution of radioactivity in each organ. Results were validated by comparing 3D-ID generated electron S factors for different-sized spheres with published data. Depending on matrix size, sphere size, and radionuclide, 1% (256(2) matrix) to 18% (64(2) matrix) agreement was obtained. RESULTS: S factor values were calculated for liver, spleen, and right and left kidneys. Cross-organ electron-absorbed fractions of up to 0.33 were obtained (e.g., (90)Y right kidney to liver). Comparisons between S factor values and values obtained assuming complete absorption of electron energy yielded differences of more than 190% ((90)Y spleen self-dose). CONCLUSION: The effect of cross-organ and self-absorbed dose is dependent on emission energy and organ geometry and should be considered in murine dose estimates. The approach used to generate these S factors is applicable to other animal systems and also to nonuniform activity distributions that may be obtained by small-animal SPECT or PET imaging or by quantitative autoradiography.