Comprehensive evaluation of CT pulmonary angiography for patients suspected of having pulmonary embolism.

Recently, CT pulmonary angiography (CTPA), especially performed with multi-detector row CT, has become a key imaging modality for pulmonary embolism. However, CTPA that was performed under clinical suspicion of pulmonary embolism has been shown to lead to high prevalence of alternative diagnosis, up to 25.4%. A comprehensive evaluation of pulmonary and extrapulmonary abnormalities including cardiovascular lesions is critical in proper diagnosis and patient care. Radiologists should be familiar with the comprehensive interpretation of CTPA to facilitate differential diagnosis and further treatment decision.

Usefulness of multidetector-row computed tomography in evaluating adult cor triatriatum.

Cor triatriatum is a rare congenital cardiac disease in which a fibromuscular membrane divides the left atrium into 2 distinct chambers. The most common presenting symptoms in adults are dyspnea, hemoptysis, and orthopnea, which mimic mitral stenosis in presentation. Cor triatriatum is commonly evaluated and diagnosed by echocardiography.Herein, we describe the case of a 39-year-old woman who had experienced worsening dyspnea for 7 months. Cor triatriatum was diagnosed by transthoracic and transesophageal echocardiography. A 3-dimensional reconstruction image produced by multidetector-row computed tomography (40 slices) clearly showed the intra-atrial membrane and the communicating fenestration, in conjunction with coronary and whole-heart evaluation in a single study. On the basis of our findings, we conclude that multidetector-row computed tomography may be a useful tool, as an adjunct to echocardiography, for whole-heart evaluation before operative correction of cor triatriatum.

Comprehensive evaluation of ischemic heart disease using MDCT.

OBJECTIVE: Recently 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. CONCLUSION: Radiologists should be familiar with the protocol design and comprehensive interpretation of cardiac MDCT to provide comprehensive treatment suggestions for the patients.

Neonatal cardiac multidetector row CT: why and how we do it.

Neonatal congenital heart disease is a most difficult area of diagnostic radiology because of the small patient body size and fast resting heart rate. Recently, the spatial and temporal resolution of multidetector-row CT (MDCT) has evolved so that neonatal congenital heart disease can be precisely diagnosed. We describe the role of MDCT in neonatal congenital heart disease and offer tips for the scanning procedure to familiarize radiologists with this developing field.

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

OBJECTIVE: The 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). SUBJECTS AND METHODS: During 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 Student's t test. RESULTS: Enhancement 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. CONCLUSION: Iodixanol 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.

Polyarteritis nodosa: MDCT as a "one-stop shop" modality for whole-body arterial evaluation.

Polyarteritis nodosa is a rare disease, which is characterized by aneurysm formation and occlusion in the arteries of multiple systems. Due to its extensive involvement, whole-body evaluation is necessary for diagnosis and treatment monitoring. We report a case of polyarteritis nodosa using multidetector-row computed tomography (MDCT) as a "one-stop shop" modality for whole-body arterial evaluation. With precise protocol design, MDCT can be used as a reliable noninvasive modality providing comprehensive whole-body arterial evaluation.

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

BACKGROUND: There 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). OBJECTIVE: To study the patterns and prevalence of VA and CCA anomalies in patients with ARSCA. MATERIALS AND METHODS: In 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. RESULTS: In 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. CONCLUSION: If 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.

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

BACKGROUND: Multidetector 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. OBJECTIVE: To compare the detection rate and image quality of neonatal coronary arteries on MDCT using ECG-gated and non-ECG-gated techniques. MATERIALS AND METHODS: Twelve 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. RESULTS: In 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. CONCLUSION: For 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.

Gradual pulmonary artery enhancement: new sign of septal defects on CT.

OBJECTIVE: Hemodynamic 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. CONCLUSION: Gradual pulmonary artery enhancement is a newly recognized CT sign that may be helpful in evaluating septal defects.

Use of 40-detector row computed tomography before catheter coronary angiography to select early conservative versus early invasive treatment for patients with low-risk acute coronary syndrome.

OBJECTIVE: Using catheter coronary angiography (CAG) as reference standard, we examined the agreement of 40-detector row computed tomography (MDCT) in triaging patients into the 2 controversial strategies of managing low-risk acute coronary syndrome (ACS). METHODS: Seventy-eight patients with low-risk ACS received both MDCT and CAG. Early invasive strategy was assigned for the patient if there was significant stenosis (> or =50% diameter stenosis) in any of the coronary artery segments with diameter larger than 1.5 mm. The results of MDCT were compared with the CAG for agreement. RESULTS: The overall agreement of the early conservative/early invasive strategy assignment was 92.3%, with kappa value of 0.82 between MDCT and CAG. Only 1 patient needing early invasive strategy was missed by MDCT. CONCLUSION: Forty-detector row computed tomography is reliable in triaging patients into the 2 strategies of managing low-risk ACS.

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

OBJECTIVE: The essay describes the protocol for and interpretation of MDCT scans in the evaluation of patients after insertion of an Amplatzer septal occluder. CONCLUSION: In 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.

Homogeneous enhancement in pediatric thoracic CT aortography using a novel and reproducible method: contrast-covering time.

OBJECTIVE: This study compares the empiric setting and contrast-covering time (CCT) concept for i.v. contrast injection in pediatric thoracic CT aortography. SUBJECTS AND METHODS: A total of 113 pediatric patients referred for thoracic CT aortography were classified into four groups: group 1 (1-5 years old, CCT), group 2A (6-10 years old, CCT), group 2B (6-10 years old, empiric setting), and group 3 (11-15 years old, CCT). The CT attenuation values from the left common carotid artery to the descending aorta were recorded every 0.5 second. The quantitative bolus geometric analysis of each group included average enhancement, SD within the patient, and slope of enhancement. Groups 2A and 2B were compared to determine whether better bolus geometry could be obtained with the CCT concept than with the traditional empiric setting. Groups 1, 2A, and 3 were compared to determine whether homogeneous bolus geometry could be obtained in different age groups. RESULTS: More homogeneous enhancement was obtained with the CCT concept than the empiric setting with a smaller SD of enhancement (25.5 +/- 8.5 H vs 49.3 +/- 16.2 H, p < 0.001). Furthermore, in the three different age groups (groups 1, 2A, and 3) examined using the CCT concept, there was no significant difference in the average enhancement (415.7 +/- 83.6 H, 422.8 +/- 97.1 H, 392.0 +/- 78.5 H, respectively; all p > 0.05), SD of enhancement (28.5 +/- 9.8 H, 25.5 +/- 8.5 H, 28.5 +/- 14.6 H, respectively; all p > 0.05), or enhancement slopes (-5.6 +/- 18.0 H, -2.7 +/- 10.7 H, -5.4 +/- 12.3 H, respectively; all p > 0.05). CONCLUSION: The CCT concept yields more homogeneous enhancement than the empiric setting. It also can routinely obtain homogeneous bolus geometry in patients in different age groups.

Radiographic, clinical, and prognostic features of complicated and uncomplicated community-acquired lobar pneumonia in children.

BACKGROUND AND PURPOSE: The incidence of community-acquired lobar pneumonia in conjunction with either necrosis or empyema in children has rapidly increased in recent years. This study aimed to evaluate the radiographic, clinical, and predicted factors of complicated and uncomplicated lobar pneumonia in children. METHODS: This retrospective study included 131 patients younger than 18 years of age with community-acquired lobar pneumonia treated between January 2002 and March 2005. Multiple logistic regression analysis was performed to demonstrate the risk factors of complicated lobar pneumonia. RESULTS: The proportion of children with lobar pneumonia in children increased dramatically from 7% in 2002 to 19% in 2004. Analysis revealed the presence of elevated C-reactive protein level (>12 mg/dL) [odds ratio (OR), 3.51; 95% confidence interval (CI), 1.61-7.66], persistent fever for more than 1 week before admission (OR, 1.14; 95% CI, 1.04-1.26), and multilobar (> or =2 lobes) confluent lung opacity on chest radiographs (OR, 2.83; 95% CI, 1.27-6.33) were independent predictors of the occurrence of complicated lobar pneumonia. A progressive increase in the number of penicillin-non-susceptible Streptococcus pneumoniae isolates was found during the study period. Prolonged fever was a common clinical feature of hospitalized children with lobar pneumonia. Failure of consolidative pneumonia to respond to appropriate antibiotic treatment within 4.4 days was associated with the development of necrosis or empyema. CONCLUSIONS: Complicated and uncomplicated lobar pneumonia are difficult to distinguish based on clinical symptoms at the time of admission. The presence of the above risk factors can help in the early diagnosis of complicated lobar pneumonia.

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.

BACKGROUND: Echocardiography 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. OBJECTIVE: To verify the technical and clinical feasibilities of replacing diagnostic cardiac catheterization with multidetector-row CT (MDCT) in neonatal complex congenital heart disease. MATERIALS AND METHODS: Over 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. RESULTS: A 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 471 HU. No obvious beam-hardening artefact was observed. CONCLUSION: The 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.

A rare hernia of intra-abdominal fat in the thorax under an intact diaphragm: multidetector computed tomography.

Neither abdominal wall hernia nor diaphragmatic hernia is an unusual disease. But some may have difficulty diagnosing the presence of intra-abdominal fat in the thorax under an intact diaphragm. We report a case with an external compression of the right lower lung from intra-abdominal fat owing to a hernia through the right lateral abdominal wall and secondary through the ninth intercostal space of the chest wall to the right lower thorax without traumatic history. Multiple images, including multidetector row computed tomography, are reviewed.

Classification of clustered microcalcifications using a Shape Cognitron neural network.

A new shape recognition-based neural network built with universal feature planes, called Shape Cognitron (S-Cognitron) is introduced to classify clustered microcalcifications. The architecture of S-Cognitron consists of two modules and an extra layer, called 3D figure layer lies in between. The first module contains a shape orientation layer, built with 20 cell planes of low level universal shape features to convert first-order shape orientations into numeric values, and a complex layer, to extract second-order shape features. The 3D figure layer is a feature extract-display layer that extracts the shape curvatures of an input pattern and displays them as a 3D figure. It is then followed by a second module made up of a feature formation layer and a probabilistic neural network-based classification layer. The system is evaluated by using Nijmegen mammogram database and experimental results show that sensitivity and specificity can reach 86.1 and 74.1%, respectively.

Synovial sarcoma of the mediastinum.

Synovial sarcomas are exceedingly rare neoplasms of the mediastinum. We herein report a case of synovial sarcoma occurring in the mediastinum of an 11-year-old boy. The patient presented with superior vena cava syndrome, and the tumor was found located in the upper superior mediastinum. Due to the large size of the tumor making complete removal impossible, an incisional biopsy was performed. The biopsy showed the typical biphasic pattern of synovial sarcoma. After surgery, the patient received radiotherapy and chemotherapy, and was still alive 2 years after diagnosis.