Fast Quantitative Magnetic Resonance Imaging Evaluation of Hydrocephalus Using 3-Dimensional Fluid-Attenuated Inversion Recovery: Initial Experience.

OBJECTIVE: This study aimed to demonstrate the initial experience of using fast quantitative magnetic resonance imaging (MRI) to evaluate hydrocephalus. METHODS: A total of 109 brain MRI volumetry examinations (acquisition time, 7 minutes 30 seconds) were performed in 72 patients with hydrocephalus. From the measured ventricular system and brain volumes, ventricle-brain volume percentage was calculated to standardize hydrocephalus severity (processing time, <5 minutes). The obtained values were categorized into no, mild, and severe based on the fronto-occipital horn ratio (FOHR) and the ventricle-brain volume percentages reported in the literature. The measured volumes and percentages were compared between patients with mild hydrocephalus and those with severe hydrocephalus. The diagnostic performance of brain hydrocephalus MRI volumetry was evaluated using receiver operating characteristic curve analysis. RESULTS: Ventricular volumes and ventricle-brain volume percentages were significantly higher in in patients with severe hydrocephalus than in those with mild hydrocephalus (FOHR-based severity: 352.6 ± 165.6 cm 3 vs 149.1 ± 78.5 cm 3 , P < 0.001, and 26.8% [20.8%-33.1%] vs 12.1% ± 6.0%, P < 0.001; percentage-based severity: 359.5 ± 143.3 cm 3 vs 137.0 ± 62.9 cm 3 , P < 0.001, and 26.8% [21.8%-33.1%] vs 11.3% ± 4.2%, P < 0.001, respectively), whereas brain volumes were significantly lower in patients with severe hydrocephalus than in those with mild hydrocephalus (FOHR-based severity: 878.1 ± 363.5 cm 3 vs 1130.1 cm 3 [912.1-1244.2 cm 3 ], P = 0.006; percentage-based severity: 896.2 ± 324.6 cm 3 vs 1142.3 cm 3 [944.2-1246.6 cm 3 ], P = 0.005, respectively). The ventricle-brain volume percentage was a good diagnostic parameter for evaluating the degree of hydrocephalus (area under the curve, 0.855; 95% confidence interval, 0.719-0.990; P < 0.001). CONCLUSIONS: Brain MRI volumetry can be used to evaluate hydrocephalus severity and may provide guide interpretation because of its rapid acquisition and postprocessing times.

Complimentary Cardiac Computed Tomography Ventricular Volumetry-Derived Metrics of Severity in Patients with Ebstein Anomaly: Comparison with Echocardiography-Based Severity Indices.

Detailed three-dimensional cardiac segmentations using cardiac computed tomography (CT) data is technically feasible in patients with Ebstein anomaly, but its complementary role has not been evaluated. This single-center, retrospective study was aimed to evaluate the complementary role of cardiac CT ventricular volumetry in evaluating the severity of Ebstein anomaly. Preoperative cardiac CT ventricular volumetry was performed in 21 children with Ebstein anomaly. CT-based ventricular functional measures were compared between Carpentier types, and between definitive surgical repair types. The Celermajer severity index measured with echocardiography was correlated with CT-based functional parameters. Total right ventricle (RV) and functional RV (fRV) volumes, fRV fraction, fRV/left ventricle (LV) volume ratio, and end-diastolic CT severity index demonstrated statistically significant differences between Carpentier type A/B and Carpentier type C/D (p < 0.05). The Celermajer severity index measured with echocardiography showed a high positive correlation with the end-diastolic CT severity index (R = 0.720, p < 0.002). There were no statistically significant differences in both echocardiography- and CT-based functional measures between patients with biventricular repair and patients with one-and-a-half or univentricular repair (p > 0.05). Compared with echocardiography, cardiac CT ventricular volumetry can provide the severity of Ebstein anomaly objectively and may be used in select patients when echocardiographic results are inconclusive or inconsistent.

Pulmonary Atresia with Intact Ventricular Septum: Correlation of Preoperative Computed Tomography-Derived Parameters with Echocardiographic Tricuspid Valve Z-Score and Surgical Outcomes.

The role of preoperative cardiac computed tomography (CT) in neonates with pulmonary atresia and intact ventricular septum (PA-IVS) remains unclear. This study was aimed to elaborate the role of preoperative CT-derived anatomical and functional findings in planning treatment strategies in neonates with PA-IVS. The presence of ventriculocoronary arterial connections was evaluated by CT. CT-derived ventricular volumetric parameters were compared and correlated with echocardiographic tricuspid valve (TV) z-score in 12 neonates with PA-IVS. Cardiac CT and echocardiographic findings were compared between definite surgical types (median follow-up, 4 years). Ventriculocoronary arterial connections were identified with CT in 58.3% of cases (7/12) and associated with higher incidence of Fontan procedure (42.9%, 3/7) and high mortality (28.6%, 2/7). The CT-derived and echocardiographic TV z-scores exhibited a high correlation (R = 0.924, p < 0.001). The CT-derived right ventricle (RV) volume and RV-left ventricle volume ratio also displayed high correlations (R = 0.875 and 0.867, respectively; p < 0.001) with echocardiographic TV z-score. More positive echocardiographic TV z-score, high CT-derived RV end-diastolic volume and RV-left ventricle volume ratio, and low CT-derived left ventricular end-diastolic volume were observed in biventricular surgery group (N = 2), compared to Fontan operation (N = 3) and 1.5 ventricular surgery (N = 3) groups, and mortality cases (N = 3). Preoperative CT-derived coronary artery anatomy and ventricular volumetric parameters may supplement treatment planning in neonates with PA-IVS especially when multifactorial decision including echocardiographic TV z-score is in a gray zone.W.

Partial voxel interpolation to reduce partial volume error of cardiac computed tomography ventricular volumetry in patients with congenital heart disease.

BACKGROUND: Varying degrees of partial volume error depending on the complexity of the endocardial borders are inevitable in threshold-based cardiac computed tomography (CT) ventricular volumetry. These errors can potentially be reduced by using a partial voxel interpolation (PVI) method, but this has not been tested for cardiac CT ventricular volumetry. OBJECTIVE: To evaluate the partial volume error-reducing effects of the PVI method in cardiac CT ventricular volumetry among patients with congenital heart disease (CHD). MATERIALS AND METHODS: The cardiac CT ventricular volumetry data were obtained from 55 patients (median age 12.0 years) with CHD. The ventricular and myocardial volumes, ejection fraction and ventricular mass-volume ratio were quantified and compared before and after the PVI method. The correlation between the myocardial volumes in the end-systolic and end-diastolic phases was tested. The effect of the PVI method on the classification of ventricular hypertrophy was evaluated. RESULTS: The indexed ventricular volumes after PVI were significantly smaller (7.4-11.5%) than those before PVI (P<0.001). In contrast, the indexed myocardial volumes were significantly larger (6.2-27.7%) after PVI (P<0.001). The ejection fractions and mass-volume ratios were significantly larger (1.6-2.2% and 19.7-42.5%, respectively) after PVI (P<0.001 and P<0.001, respectively). The indexed myocardial masses showed prominently high correlation between the end-systolic and end-diastolic phases (R, 0.961-0.990; P<0.001). The proportions of no and severe hypertrophy were significantly decreased (P<0.002) and increased (P<0.032), respectively, after the application of the PVI method. CONCLUSION: The PVI method can reduce partial volume error in cardiac CT ventricular volumetry among patients with CHD.

Pulmonary vascular volume ratio measured by cardiac computed tomography in children and young adults with congenital heart disease: comparison with lung perfusion scintigraphy.

BACKGROUND: Lung perfusion scintigraphy is regarded as the gold standard for evaluating differential lung perfusion ratio in congenital heart disease. OBJECTIVE: To compare cardiac CT with lung perfusion scintigraphy for estimated pulmonary vascular volume ratio in patients with congenital heart disease. MATERIALS AND METHODS: We included 52 children and young adults (median age 4 years, range 2 months to 28 years; 31 males) with congenital heart disease who underwent cardiac CT and lung perfusion scintigraphy without an interim surgical or transcatheter intervention and within 1 year. We calculated the right and left pulmonary vascular volumes using threshold-based CT volumetry. Then we compared right pulmonary vascular volume percentages at cardiac CT with right lung perfusion percentages at lung perfusion scintigraphy by using paired t-test and Bland-Altman analysis. RESULTS: The right pulmonary vascular volume percentages at cardiac CT (66.3 ± 14.0%) were significantly smaller than the right lung perfusion percentages at lung perfusion scintigraphy (69.1 ± 15.0%; P=0.001). Bland-Altman analysis showed a mean difference of -2.8 ± 5.8% and 95% limits of agreement (-14.1%, 8.5%) between these two variables. CONCLUSION: Cardiac CT, in a single examination, can offer pulmonary vascular volume ratio in addition to pulmonary artery anatomy essential for evaluating peripheral pulmonary artery stenosis in patients with congenital heart disease. However there is a wide range of agreement between cardiac CT and lung perfusion scintigraphy.

Atresia of the bilateral pulmonary veins: a rare and dismal anomaly identified on cardiac CT.

BACKGROUND: Imaging findings of bilateral pulmonary vein atresia have not been described. OBJECTIVE: To describe cardiac CT findings and clinical outcomes of bilateral pulmonary vein atresia. MATERIALS AND METHODS: Three newborns with bilateral pulmonary vein atresia were encountered at our institution during a period of 8 years. We evaluated prenatal echocardiographic findings, clinical presentations, postnatal echocardiographic findings, chest radiographic findings, cardiac CT findings and clinical outcomes. RESULTS: All newborns presented immediately after birth with severe cyanosis, respiratory distress and acidosis that were unresponsive to medical management. Prenatal and postnatal echocardiographic studies and chest radiography were misleading, inconclusive or nonspecific in making the diagnosis in these children; however cardiac CT clearly demonstrated atresia of the bilateral pulmonary veins with multiple small mediastinal collateral veins and pulmonary edema. Surgical treatments were not feasible for this anomaly. Their clinical outcomes were universally dismal and all infants died within 3 days. CONCLUSION: Cardiac CT provides an accurate diagnosis of bilateral pulmonary vein atresia and leads to prompt treatment decision in these children.

Left ventricle volume measured by cardiac CT in an infant with a small left ventricle: a new and accurate method in determining uni- or biventricular repair.

Left ventricle volume is a factor in determining the type of surgical treatment in patients with a hypoplastic left ventricle. The volume of the hypoplastic left ventricle can be measured by echocardiography and cardiac MRI. In an infant with congenital heart disease and a small left ventricle, cardiac CT was used for this measurement and biventricular repair was performed. The left ventricular end-diastolic volume index showed a gradual increase from 23.2 to 47.9 ml/m(2) 4 months after the biventricular repair, and the postoperative outcome was excellent. Cardiac CT provided an accurate volume of the hypoplastic left ventricle in this infant with congenital heart disease; that volume was used to determine the type of surgical repair.

Identification of rapid progression of right ventricular functional measures using three-dimensional cardiac computed tomography after total surgical correction of tetralogy of Fallot.

OBJECTIVE: To identify subsets of patients with tetralogy of Fallot (TOF) after total surgical correction demonstrating the rapid progression of right ventricle (RV) functional measures using cardiac computed tomography (CT) ventricular volumetry. METHODS: Rapid or slow progression of RV functional measures was determined in 109 patients with TOF who underwent cardiac CT ventricular volumetry more than twice after total surgical correction. Patient age, body surface area, postoperative days, the time interval between the first and last cardiac CT examinations, and CT-based functional measures were evaluated using binary logistic regression to determine the predictors of the rapid progression. Receiver operating characteristic curve analysis was performed to evaluate diagnostic performance of the potential predictors. RESULTS: The rapid progression of indexed RV end-systolic volume (ESV) (≥2.7 mL/m2/year) and indexed RV end-diastolic volume (≥0.9 mL/m2/year) could be predicted by RV ejection fraction (EF) at the last cardiac CT with an odds ratio of 1.340 (95 % confidence interval [CI], 1.122-1.600; p = 0.001) and age at the last cardiac CT with an odds ratio of 8.255 (95 % CI, 1.531-44.513; p = 0.014), respectively. RV EF at the last cardiac CT showed the highest diagnostic performance (area under the curve = 0.799; p < 0.002) for the rapid progression of indexed RV ESV. CONCLUSION: Cardiac CT ventricular volumetry can be used to identify patients demonstrating the rapid progression of RV functional measures after total surgical correction of TOF and follow-up imaging protocols can be individually optimized based on initial progression rate.

Prediction of pulmonary hypertension using central-to-peripheral pulmonary vascular volume ratio on three-dimensional cardiothoracic CT in patients with congenital heart disease.

PURPOSE: To evaluate whether the central-to-peripheral pulmonary vascular volume ratio measured using three-dimensional cardiothoracic CT can serve as a potential predictor of pulmonary hypertension (PH) in patients with congenital heart disease. METHODS: Cardiothoracic CT was used to quantify right and left total, central, and peripheral pulmonary vascular volumes segmented based on a three-dimensional threshold-based approach in 60 patients with congenital heart disease (group with PH, n = 30; group without PH, n = 30). The CT-based central-to-peripheral pulmonary vascular volume ratios were correlated with the echocardiography-based maximum velocity of tricuspid regurgitation (TR Vmax) and systolic pulmonary arterial pressure (PAP) values. The diagnostic ability of the central-to-peripheral pulmonary vascular volume ratio to predict PH was analyzed. RESULTS: The central-to-peripheral pulmonary vascular volume ratios were significantly higher in the group with PH compared to the group without PH (1.6 ± 0.9 vs. 0.8 ± 0.3 for the right side, p < 0.001; 2.4 ± 2.2 vs. 1.0 ± 1.4 for the left side, p < 0.004). The right central-to-peripheral pulmonary volume ratios were significantly positively correlated with the TR Vmax and estimated systolic PAP values (R = 0.627 and 0.633, respectively; p < 0.001) in patients with and without PH, while the ratios were moderately correlated with the TR Vmax and estimated systolic PAP values (R = 0.431 and 0.435, respectively; p < 0.020) in the group with PH. The right and left central-to-peripheral pulmonary vascular volume ratios demonstrated a good diagnostic ability for predicting the presence of PH (area under the receiver-operating characteristic curve = 0.867, p < 0.001 and 0.859, p < 0.001 for the right and left, respectively). CONCLUSION: The CT-based central-to-peripheral pulmonary vascular volume ratio can be used to predict PH in patients with congenital heart disease.

Pattern Analysis of Left Ventricular Remodeling Using Cardiac Computed Tomography in Children with Congenital Heart Disease: Preliminary Results.

OBJECTIVE: To assess left ventricular remodeling patterns using cardiac computed tomography (CT) in children with congenital heart disease and correlate these patterns with their clinical course. MATERIALS AND METHODS: Left ventricular volume and myocardial mass were quantified in 17 children with congenital heart disease who underwent initial and follow-up end-systolic cardiac CT studies with a mean follow-up duration of 8.4 ± 9.7 months. Based on changes in the indexed left ventricular myocardial mass (LVMi) and left ventricular mass-volume ratio (LVMVR), left ventricular remodeling between the two serial cardiac CT examinations was categorized into one of four patterns: pattern 1, increased LVMi and increased LVMVR; pattern 2, decreased LVMi and decreased LVMVR; pattern 3, increased LVMi and decreased LVMVR; and pattern 4, decreased LVMi and increased LVMVR. Left ventricular remodeling patterns were correlated with unfavorable clinical courses. RESULTS: Baseline LVMi and LVMVR were 65.1 ± 37.9 g/m² and 4.0 ± 3.2 g/mL, respectively. LVMi increased in 10 patients and decreased in seven patients. LVMVR increased in seven patients and decreased in 10 patients. Pattern 1 was observed in seven patients, pattern 2 in seven, and pattern 3 in three patients. Unfavorable events were observed in 29% (2/7) of patients with pattern 1 and 67% (2/3) of patients with pattern 3, but no such events occurred in pattern 2 during the follow-up period (4.4 ± 2.7 years). CONCLUSION: Left ventricular remodeling patterns can be characterized using cardiac CT in children with congenital heart disease and may be used to predict their clinical course.

Optimal Attenuation Threshold for Quantifying CT Pulmonary Vascular Volume Ratio.

OBJECTIVE: To evaluate the effects of attenuation threshold on CT pulmonary vascular volume ratios in children and young adults with congenital heart disease, and to suggest an optimal attenuation threshold. MATERIALS AND METHODS: CT percentages of right pulmonary vascular volume were compared and correlated with percentages calculated from nuclear medicine right lung perfusion in 52 patients with congenital heart disease. The selected patients had undergone electrocardiography-synchronized cardiothoracic CT and lung perfusion scintigraphy within a 1-year interval, but not interim surgical or transcatheter intervention. The percentages of CT right pulmonary vascular volumes were calculated with fixed (80-600 Hounsfield units [HU]) and adaptive thresholds (average pulmonary artery enhancement [PAavg] divided by 2.50, 2.00, 1.75, 1.63, 1.50, and 1.25). The optimal threshold exhibited the smallest mean difference, the lowest p-value in statistically significant paired comparisons, and the highest Pearson correlation coefficient. RESULTS: The PAavg value was 529.5 ± 164.8 HU (range, 250.1-956.6 HU). Results showed that fixed thresholds in the range of 320-400 HU, and adaptive thresholds of PAavg/1.75-1.50 were optimal for quantifying CT pulmonary vascular volume ratios. The optimal thresholds demonstrated a small mean difference of ≤ 5%, no significant difference (> 0.2 for fixed thresholds, and > 0.5 for adaptive thresholds), and a high correlation coefficient (0.93 for fixed thresholds, and 0.91 for adaptive thresholds). CONCLUSION: The optimal fixed and adaptive thresholds for quantifying CT pulmonary vascular volume ratios appeared equally useful. However, when considering a wide range of PAavg, application of optimal adaptive thresholds may be more suitable than fixed thresholds in actual clinical practice.

Computed Tomography-Based Ventricular Volumes and Morphometric Parameters for Deciding the Treatment Strategy in Children with a Hypoplastic Left Ventricle: Preliminary Results.

Objective: To determine the utility of computed tomography (CT) ventricular volumes and morphometric parameters for deciding the treatment strategy in children with a hypoplastic left ventricle (LV). Materials and Methods: Ninety-four consecutive children were included in this study and divided into small LV single ventricle repair (SVR) (n = 28), small LV biventricular repair (BVR) (n = 6), disease-matched control (n = 19), and control (n = 41) groups. The CT-based indexed LV volumes, LV-to-right-ventricular (LV/RV) volume ratio, left-to-right atrioventricular valve (AVV) area ratio, left-to-right AVV diameter ratio, and LV/RV long dimension ratio were compared between groups. Proportions of preferred SVR in the small LV SVR group suggested by the parameters were evaluated. Results: Indexed LV end-systolic (ES) and end-diastolic (ED) volumes in the small LV SVR group (6.3 ± 4.0 mL/m2 and 14.4 ± 10.2 mL/m2, respectively) were significantly smaller than those in the disease-matched control group (16.0 ± 4.7 mL/m2 and 37.7 ± 12.0 mL/m2, respectively; p < 0.001) and the control group (16.0 ± 5.5 mL/m2 and 46.3 ± 10.8 mL/m2, respectively; p < 0.001). These volumes were 8.3 ± 2.4 mL/m2 and 21.4 ± 5.3 mL/m2, respectively, in the small LV BVR group. ES and ED indexed LV volumes of < 7 mL/m2 and < 17 mL/m2, LV/RV volume ratios of < 0.22 and < 0.25, AVV area ratios of < 0.33 and < 0.24, and AVV diameter ratios of < 0.52 and < 0.46, respectively, enabled the differentiation of a subset of patients in the small LV SVR group from those in the two control groups. One patient in the small LV biventricular group died after BVR, indicating that this patient might not have been a good candidate based on the suggested cut-off values. Conclusion: CT-based ventricular volumes and morphometric parameters can suggest cut-off values for SVR in children with a hypoplastic LV.

Semiautomatic three-dimensional CT ventricular volumetry in patients with congenital heart disease: agreement between two methods with different user interaction.

To assess agreement between two semi-automatic, three-dimensional (3D) computed tomography (CT) ventricular volumetry methods with different user interactions in patients with congenital heart disease. In 30 patients with congenital heart disease (median age 8 years, range 5 days-33 years; 20 men), dual-source, multi-section, electrocardiography-synchronized cardiac CT was obtained at the end-systolic (n = 22) and/or end-diastolic (n = 28) phase. Nineteen left ventricle end-systolic (LV ESV), 28 left ventricle end-diastolic (LV EDV), 22 right ventricle end-systolic (RV ESV), and 28 right ventricle end-diastolic volumes (RV EDV) were successfully calculated using two semi-automatic, 3D segmentation methods with different user interactions (high in method 1, low in method 2). The calculated ventricular volumes of the two methods were compared and correlated. A P value <0.05 was considered statistically significant. LV ESV (35.95 ± 23.49 ml), LV EDV (88.76 ± 61.83 ml), and RV ESV (46.87 ± 47.39 ml) measured by method 2 were slightly but significantly smaller than those measured by method 1 (41.25 ± 26.94 ml, 92.20 ± 62.69 ml, 53.61 ± 50.08 ml for LV ESV, LV EDV, and RV ESV, respectively; P ≤ 0.02). In contrast, no statistically significant difference in RV EDV (122.57 ± 88.57 ml in method 1, 123.83 ± 89.89 ml in method 2; P = 0.36) was found between the two methods. All ventricular volumes showed very high correlation (R = 0.978, 0.993, 0.985, 0.997 for LV ESV, LV EDV, RV ESV, and RV EDV, respectively; P < 0.001) between the two methods. In patients with congenital heart disease, 3D CT ventricular volumetry shows good agreement and high correlation between the two methods, but method 2 tends to slightly underestimate LV ESV, LV EDV, and RV ESV.