I-Chen Tsai

Using multidetector-row CT in neonates with complex congenital heart disease to replace diagnostic cardiac catheterization for anatomical investigation: initial experiences in technical and clinical feasibility.

BackgroundEchocardiography is the first-line modality for the investigation of neonatal congenital heart disease. Diagnostic cardiac catheterization, which has a small but recognized risk, is usually performed if echocardiography fails to provide a confident evaluation of the lesions.ObjectiveTo verify the technical and clinical feasibilities of replacing diagnostic cardiac catheterization with multidetector-row CT (MDCT) in neonatal complex congenital heart disease.Materials and methodsOver a 1-year period we prospectively enrolled all neonates with complex congenital heart disease referred for diagnostic cardiac catheterization after initial assessment by echocardiography. MDCT was performed using a 40-detector-row CT scanner with dual syringe injection. A multidisciplinary congenital heart disease team evaluated the MDCT images and decided if further diagnostic cardiac catheterization was necessary. The accuracy of MDCT in detecting separate cardiovascular anomalies and bolus geometry of contrast enhancement were calculated.ResultsA total of 14 neonates were included in the study. No further diagnostic cardiac catheterization was needed in any neonate. The accuracy of MDCT in diagnosing separate cardiovascular anomalies was 98% (53/54) with only one atrial septal defect missed in a patient with coarctation syndrome. The average cardiovascular enhancement in evaluated chambers was 471xa0HU. No obvious beam-hardening artefact was observed.ConclusionThe technical and clinical feasibility of MDCT in complex congenital heart disease in neonates is confirmed. After initial assessment with echocardiography, MDCT could probably replace diagnostic cardiac catheterization for further anatomical clarification in neonates.

CT-Guided Core Biopsy of Lung Lesions: A Primer

OBJECTIVEnCT-guided core biopsy is playing an increasing role in the diagnosis of benign disease, cellular differentiation, somatic mutation analysis, and molecular fingerprint analysis.nnnCONCLUSIONnIn this article, we summarize the basic concepts, protocols, and techniques that we use for CT-guided core biopsy of lung lesions to assist radiologists in obtaining diagnostic specimens while reducing preventable complications.

Visualization of neonatal coronary arteries on multidetector row CT: ECG-gated versus non-ECG-gated technique

BackgroundMultidetector CT (MDCT) seems to be a promising tool for detection of neonatal coronary arteries, but whether the ECG-gated or non-ECG-gated technique should be used has not been established.ObjectiveTo compare the detection rate and image quality of neonatal coronary arteries on MDCT using ECG-gated and non-ECG-gated techniques.Materials and methodsTwelve neonates with complex congenital heart disease were included. The CT scan was acquired using an ECG-gated technique, and the most quiescent phase of the RR interval was selected to represent the ECG-gated images. The raw data were then reconstructed without the ECG signal to obtain non-ECG-gated images. The detection rate and image quality of nine coronary artery segments in the two sets of images were then compared. A two-tailed paired t test was used with P values <0.05 considered as statistically significant.ResultsIn all coronary segments the ECG-gated technique had a better detection rate and produced images of better quality. The difference between the two techniques ranged from 25% in the left main coronary artery to 100% in the distal right coronary artery.ConclusionFor neonates referred for MDCT, if evaluation of coronary artery anatomy is important for the clinical management or surgical planning, the ECG-gated technique should be used because it can reliably detect the coronary arteries.

Vertebral and carotid artery anomalies in patients with aberrant right subclavian arteries

BackgroundThere is little published evidence regarding the patterns and prevalence of vertebral artery (VA) and common carotid artery (CCA) anomalies in patients with an aberrant right subclavian artery (ARSCA).ObjectiveTo study the patterns and prevalence of VA and CCA anomalies in patients with ARSCA.Materials and methodsIn a 2-year period we reviewed the children referred with suspected vascular ring who had undergone multidetector-row CT. Patients with ARSCA were reviewed for VA and CCA patterns and their prevalence and relevance were calculated.ResultsIn total, 102 patients with ARSCA were identified. VA anomalies were present in 16 patients (15.7%), and CCA anomalies (common carotid trunk) in 21 patients (20.6%). In some patients with VA anomalies, the right VA arose from the right CCA and in some the left VA arose from the aortic arch. When the left VA arose from the aortic arch it was situated between the left CCA and the left SCA or between the left SCA and the ARSCA.ConclusionIf neurointerventionalists understand these potential anomalies and their prevalence, time and contrast medium could be saved when catheterizing the VA and CCA in patients with ARSCA.

Comprehensive evaluation of ischemic heart disease using MDCT.

OBJECTIVEnRecently MDCT has become widely used for the evaluation of ischemic heart disease, but clinically the evaluation is primarily focused on the coronary artery only. We describe why and how to comprehensively evaluate the cardiac CT scan, including myocardium, motion, viability, valve, and perfusion aspects related to ischemic heart disease.nnnCONCLUSIONnRadiologists should be familiar with the protocol design and comprehensive interpretation of cardiac MDCT to provide comprehensive treatment suggestions for the patients.

Contrast enhancement in cardiac MDCT: comparison of iodixanol 320 versus iohexol 350.

OBJECTIVEnThe objective of our study was to evaluate whether iodixanol 320 mg I/mL (iodixanol 320), with the highest iodine concentration of dimeric nonionic contrast agents on the market, results in decreased vascular or myocardial enhancement compared with iohexol 350 mg I/mL (iohexol 350).nnnSUBJECTS AND METHODSnDuring a 4-month period, 72 patients referred for cardiac MDCT were consecutively enrolled and randomized into two groups: iohexol 350 and iodixanol 320. The injection and scanning protocols were the same for both groups. Enhancement of the right heart, left heart, coronary arteries, and left ventricular (LV) myocardium in both the arterial and delayed phases was compared using two-tailed independent Students t test.nnnRESULTSnEnhancement in the right heart, left heart, coronary arteries, and LV myocardium in the arterial phase showed no statistical difference (p > 0.05) between the two groups, although the iohexol group showed slightly higher enhancement (average, 11.2 H) in all of the areas. Surprisingly, in the delayed phase, the iodixanol group displayed significantly higher (7.7 H) persistent enhancement (p < 0.05) in the LV myocardium.nnnCONCLUSIONnIodixanol 320 can provide vascular enhancement in cardiac MDCT that is similar to iohexol 350. In the delayed phase, iodixanol 320 shows significantly higher delayed enhancement (7.7 H) in the LV myocardium than iohexol 350.

MDCT evaluation after closure of atrial septal defect with an Amplatzer septal occluder.

OBJECTIVEnThe essay describes the protocol for and interpretation of MDCT scans in the evaluation of patients after insertion of an Amplatzer septal occluder.nnnCONCLUSIONnIn anatomic regions that cannot be confidently evaluated with transthoracic echocardiography, MDCT is useful for evaluating Amplatzer septal occluders for protrusion, migration, and residual shunt. Radiologists should be familiar with the imaging protocol and interpretation.

Comprehensive MDCT Evaluation of Patients With Pulmonary Hypertension: Diagnosing Underlying Causes With the Updated Dana Point 2008 Classification

OBJECTIVEnPulmonary hypertension is a challenge for imagers and clinicians, with a variety of possible underlying causes, each with its own specific treatment. Although the diagnosis is based on physiologic measurements, ECG-gated MDCT can play a vital role in elucidating underlying cardiac, vascular, and pulmonary causes.nnnCONCLUSIONnA revised system for pulmonary hypertension, the Dana Point classification, can provide a template for review of the myriad causes of this complex condition.

Arteriovenous Fistula and Graft Evaluation in Hemodialysis Patients Using MDCT: A Primer

OBJECTIVEnPatent arteriovenous fistula (AVF) is related to better prognosis and quality of life for patients on long-term dialysis. When AVF dysfunction is suspected, MDCT is a good noninvasive tool for evaluating the entire AVF structure and determining reversible conditions for treatment. The aim of this article is to introduce the scanning and interpretation techniques and to illustrate the conditions related to early and late fistula failures.nnnCONCLUSIONnMDCT is a fast, noninvasive, and accurate technique for diagnosing AVF complications. Radiologists familiar with these techniques can help to improve the prognosis and quality of life for hemodialysis patients.

Gradual Pulmonary Artery Enhancement: New Sign of Septal Defects on CT

OBJECTIVEnHemodynamic information observed on serial images obtained with bolus tracking might help in diagnosing septal defects on CT. Our purpose was to qualitatively and quantitatively examine a new sign called gradual pulmonary artery enhancement.nnnCONCLUSIONnGradual pulmonary artery enhancement is a newly recognized CT sign that may be helpful in evaluating septal defects.