Miho Sakata

Myocardial Strain Imaging for Early Detection of Cardiac Involvement in Patients with Duchenne's Progressive Muscular Dystrophy

Objective: In patients with Duchennes progressive muscular dystrophy (DMD), myocardial fibrosis begins from the epicardial half of the left ventricular posterior wall. Myocardial strain imaging by tissue Doppler echocardiography is a new method for assessing regional myocardial function. We hypothesized that this method might be useful for the early detection of subclinical myocardial involvement in DMD patients. Methods: Myocardial radial strain of the left ventricle was measured in 25 DMD patients (age: 14.8 ± 3.1 years) with a normal left ventricular shortening fraction and 25 age‐matched healthy controls. Results: Peak systolic radial strain of the posterior wall in a short‐axis view of the left ventricle was significantly lower in DMD patients compared to control subjects (P < 0.0001). In the interventricular septum, peak systolic radial strain was not significantly different between the two groups. Receiver operating characteristic curve analysis differentiated DMD patients from control patients with 92% sensitivity and 92% specificity, when the cutoff value for systolic peak strain of the posterior wall was 61%. When radial strain was measured separately for the inner and outer halves of the posterior wall, a systolic negative strain was more frequently observed in the outer half than in the inner half of the posterior wall (6/25 vs. 0/25, P < 0.05). Conclusions: Myocardial strain imaging in DMD patients was characterized by decreased peak systolic strain of the posterior wall despite normal standard echocardiographic findings. Strain measurement might be useful for early detection of subtle regional myocardial dysfunction.

Assessment of systemic-pulmonary collateral arteries in children with cyanotic congenital heart disease using multidetector-row computed tomography: Comparison with conventional angiography

BACKGROUND The present study aimed to assess the feasibility of multidetector-row computed tomography (MDCT) for the evaluation of systemic-pulmonary collateral (SPC) arteries in children with congenital heart disease associated with reduced pulmonary blood flow. METHODS Forty-eight consecutive patients (mean age 9+/-5 months; range, 0-30 months) underwent MDCT angiography of the thorax with a 16-detector row scanner prior to cardiac catheterization and operation. Conventional angiographic findings were used as a gold standard for the detection of SPC vessels. Findings on CT angiograms, including CT scans, maximum intensity projections, and three-dimensional volume-rendered images, were used to evaluate depiction of SPC arteries. Quantification of measurements at the SPC artery diameter was evaluated independently on MDCT and conventional invasive angiography. RESULTS Among the 48 patients, 115 SPC arteries were identified with conventional angiography, and 94 SPC arteries were identified with MDCT. In 89 (77%) vessels, concordant findings were observed with both modalities, with adequate depiction in 53 vessels and suboptimal depiction in 36 vessels. In 26 (23%) vessels, MDCT was unable to identify SPC arteries. Further, CT angiography resulted in the false-positive identification of vessels in 5 cases. There was an excellent correlation between MDCT- and conventional angiography-based measurement of SPC vessel diameter (R(2)=0.83), although a systematic overestimation was observed with MDCT (bias 0.19+/-0.74 mm). CONCLUSIONS This study demonstrates that MDCT is a potentially useful tool, which may have implications for planning percutaneous interventions and surgical repair in the future.

Right ventricular myocardial deformation patterns in children with congenital heart disease associated with right ventricular pressure overload

AIMS Longitudinal wall motion of the right ventricle (RV) has been thoroughly studied in patients with RV dysfunction. However, circumferential strain of the RV free wall has yet to be investigated. Therefore, this study was conducted to assess the utility of RV free wall circumferential strain. METHODS AND RESULTS Strain profile curves were obtained using speckle tracking echocardiography from the subcostal left ventricular (LV) short-axis view in 30 normal children (normal group) and 25 patients with RV pressure overload (RVO group). The time-strain curves of three individual segmental (anterior, lateral, and inferior segments) and global circumferential deformations were evaluated. RV ejection fraction (RVEF), RV systolic pressure (RVSP), and RV fractional area change obtained in the four-chamber view and LV short-axis view [RVFAC (4CH) and RVFAC (SAX), respectively] were measured, and their relationships with RV free wall deformation were assessed. In the normal group, circumferential strain was significantly lower in the anterior segment than in the other segments. The inferior segment had a significantly larger strain than the other segments in the RVO group. Circumferential strain was predominant over longitudinal RV free wall strain in the RVO group (-18.4 ± 3.9 vs. -14.2 ± 3.8%, respectively; P < 0.005), whereas no significant difference between them was observed in the normal group (-23.0 ± 3.9 vs. -22.4 ± 4.7%, respectively). Global circumferential strain had a significantly higher correlation with RVFAC (4CH), RVFAC (SAX), RVEF, and RVSP than global longitudinal strain (P < 0.05 for all). CONCLUSION RV free wall circumferential strain provides better information about RV function than longitudinal strain in children with RVO.

Tracheal compression due to an elongated aortic arch in patients with congenital heart disease: evaluation using multidetector-row CT.

BackgroundThe airway can become obstructed as a result of compression by an elongated aortic arch.ObjectiveIn this study we evaluated tracheal compression using multidetector-row CT in patients with congenital heart disease and an elongated aortic arch.Materials and methodsThe trachea was measured at the level of the aortic arch in 205 children and young adults and then the severity of tracheal compression was determined by measuring the tracheal diameter ratio (short axis diameter/long axis diameter). Patients were divided as follows: group I (normal aortic arch; n=166), group II (transversely running aortic arch; n=22), and group III (elongated aortic arch; n=17). From the viewpoint of the relationship of the great arteries, group II had D-malposition, and group III had L-malposition.ResultsAge, height, weight and body surface area were significantly correlated with the short and long axis diameter in group I. There was a negative correlation between tracheal diameter ratio and the physical size parameters. The tracheal diameter ratio in group III was 0.50±0.13, which was significantly lower than in groups I and II (P<0.01 and 0.05, respectively).ConclusionEven apparently asymptomatic patients with an elongated aortic arch can have tracheal compression. An elongated aortic arch may be a useful predictor of tracheal compression.

Cell membrane stretch activates intermediate-conductance Ca2+-activated K+ channels in arterial smooth muscle cells.

The aim of this study is to determine the signal transduction of membrane stretch on intermediate-conductance Ca2+-activated K+ (IKca) channels in rat aorta smooth muscle cells using the patch-clamp technique. To stretch the cell membrane, both suction to the rear end of patch pipette and hypotonic shock were used. In cell-attached and inside-out patch configurations, the open probability of IKca channels increased when 20- to 45-mmHg suction was applied. Hyposmotic swelling efficiently increased IKca channel current. When the Ca2+-free solution was superfused, the activation of IKca current by the hyposmotic swelling was reduced. Furthermore, gadolinium (Gd3+) attenuated the activation of IKca channels induced by hyposmotic swelling, whereas nicardipine did not. In the experiments with Ca2+-free bath solution, pretreatment with GF109203X, a protein kinase C (PKC) inhibitor, completely abolished the stretch-induced activation of IKca currents. The stretch-induced activation of IKca channels was strongly inhibited by cytochalasin D, indicating a role for the F-actin in modulation of IKca channels by changes in cell stretching. These data suggest that cell membrane stretch activates IKca channels. In addition, the activation is associated with extracellular Ca2+ influx through stretch-activated nonselective cation channels, and is also modulated by the F-actin cytoskeleton and the activation of PKC.

Minimum-intensity projection of multidetector-row computed tomography for assessment of pulmonary hypertension in children with congenital heart disease.

BACKGROUND The present study aimed to assess the feasibility of minimum-intensity projection (minIP) images for the evaluation of pulmonary hypertension (PH) in children with congenital heart disease (CHD). METHODS A total of 70 consecutive patients (mean age, 4.6 ± 4.4 years; range, 6 months-16 years) underwent multidetector-row computed tomography (MDCT) angiography of the thorax prior to cardiac catheterization and lung perfusion scintigraphy. Contiguous axial, coronal and sagittal minIP images of 5-mm thickness were reconstructed from the contrast-enhanced CT datasets. Two reviewers evaluated the images in consensus and qualitatively graded lung parenchyma attenuation as homogeneous (Class I), slightly heterogeneous lung attenuation that does not conform to the anatomic boundaries of the secondary pulmonary lobule (Class II), and mosaic pattern (Class III). MinIP attenuation grading results were then compared with those of perfusion scintigraphy. Furthermore, the relationships between the results of these modalities and mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) were evaluated. RESULTS In 51 (73%) patients, concordant findings were observed between the modalities, although minIP showed a higher grade for heterogeneous images than did scintigraphy. mPAP and PVR showed significant difference among the minIP attenuation classes (p<0.0001 for both). High-grade heterogeneous minIP images were associated with high mPAP, high PVR, presence of major aortopulmonary collateral artery, and chromosomal abnormality. CONCLUSION MinIP is a promising technique for depicting lung perfusion and can be used as superior alternative to scintigraphy in the evaluation of PH.

Transient left temporal lobe lesion in Menkes disease may influence the generation of tonic spasms

We report a 7-month-old boy with Menkes disease who presented West syndrome. Magnetic resonance imaging (MRI) revealed atrophy of the frontal and parietal lobes, subdural hematoma on the right side, and left temporal lobe lesion (low intensity in T1-weighted imaging (T1-WI), high intensity in T2-weighted imaging (T2-WI) and low intensity in diffusion-weighted imaging (DW-I)) at 7 months of age. The apparent diffusion coefficient (ADC) was 1.68×10(-3)mm(2)/s in the left temporal lobe lesion and 1.15×10(-3)mm(2)/s on the contralateral side. (1)H-magnetic resonance spectroscopy ((1)H-MRS) revealed a decrease in N-acetylaspartate/(creatine+phosphocreatine) (NAA/Cr) (0.71) and a lactate peak in the left temporal lobe lesion. At 8 months of age, the left temporal lobe lesion disappeared, the ADC of this lesion was within the normal range (1.10×10(-3)mm(2)/s), and (1)H-MRS revealed a slight increase in NAA/Cr (1.12) and disappearance of the lactate peak. We suspected that the transient temporal lobe lesion in Menkes disease was mainly vasogenic edema. Electroencephalography (EEG) revealed left hemisphere dominant hypsarrhythmia and slowing in the left hemisphere. Ictal EEG revealed generalized slow wave burst with P3, T3 spike antecedence and the antecedent spike was consistent with left temporal lobe lesion. After disappearance of the left temporal lobe lesion, tonic spasms disappeared and EEG findings improved. In this case, the clinical course and ictal EEG suggested that epileptic activity from the left temporal lobe lesion may have given rise to tonic spasms.

Subclavian and pulmonary artery steal phenomenon in a patient with isolated left subclavian artery and right aortic arch

We describe a patient with an isolated left subclavian artery associated with right aortic arch, patent ductus arteriosus, and ventricular septal defect. As the isolated left subclavian artery is supplied by the left vertebral artery in which blood flows in the retrograde direction, this anomaly is usually responsible for a congenital subclavian steal phenomenon. Atrophy of the left cerebral hemisphere and inverted left vertebral arterial flow were clearly depicted by echoencephalography in this patient, whose subclavian artery was connected to the main pulmonary artery by a patent ductus arteriosus.

Stenting of Ductus Arteriosus in a Neonate with Truncus Arteriosus and Interrupted Aortic Arch Associated with a Right Aortic Arch

This report describes a case in which successful stenting of ductus arteriosus (DA) was performed for a 27-day-old boy with truncus arteriosus (TA) and interrupted aortic arch (IAA). The patent DA was associated with a right aortic arch. During the balloon catheter crossing of the ductus, the DA and descending aorta shifted toward the left side, making appropriate stent placement difficult. Additionally, the DA was longer than in previously reported cases with left aortic arch, thus requiring a longer stent. This experience suggests that DA stenting in neonates with TA and IAA averts surgical repair during the early neonatal period.

Assessment of Two-Component Ventricular Septum: Functional Differences in Systolic Deformation and Rotation Assessed by Speckle Tracking Imaging

The purpose of this study was to elucidate functional differences in the right and left components of the ventricular septum (Rt and Lt, respectively).