Low radiation dose in computed tomography: the role of iodine.

Recent approaches to reducing radiation exposure during CT examinations typically utilize automated dose modulation strategies on the basis of lower tube voltage combined with iterative reconstruction and other dose-saving techniques. Less clearly appreciated is the potentially substantial role that iodinated contrast media (CM) can play in low-radiation-dose CT examinations. Herein we discuss the role of iodinated CM in low-radiation-dose examinations and describe approaches for the optimization of CM administration protocols to further reduce radiation dose and/or CM dose while maintaining image quality for accurate diagnosis.

Comparison of inversion recovery and contrast-enhanced T1-weighted fat-suppressed sequences for the staging of cervical lymphoma.

In a retrospective analysis with two readers blinded to the clinical information, coronal short tau inversion recovery (STIR) images were compared to contrast-enhanced fat-saturated T1-weighted imaging (T1 CEfs) in 51 cases of cervical lymphoma. Interrater reliability was good to excellent. Although sensitivity and subjective quality of the STIR sequence were higher than those of the T1 CEfs sequence (sensitivity 85%/72%, respectively), specificity (82%/95%) as well as positive likelihood ratio (4.

Small bowel imaging with MRI.

Magnetic resonance imaging (MRI) has evolved as a powerful tool for the assessment of the small bowel. Strengths of MRI include the superb soft-tissue contrast, lack of radiation exposure, and the implementation of fast scanning techniques. Clinically relevant findings such as inflammation and tumor disease can be well-depicted.

Objective evaluation of vessel attenuation in multidetector-row computed tomographic pulmonary angiography using high-density contrast material for the detection of pulmonary embolism.

Objective: The purpose of this study was to analyze the pulmonary vessel enhancement obtainable using high-density contrast material and saline flushing with automated bolus tracking for multidetector-row computed tomographic (MDCT) pulmonary angiography in a routine clinical setting.

Methods: Attenuation values of pulmonary vessels were retrospectively measured in 51 CT scans performed on a 40-channel MDCT for unselected emergency patients with clinically suspected pulmonary embolism.

Results: Mean vascular attenuation measured 326.

Coronary MR imaging: navigator echo biofeedback increases navigator efficiency--initial experience.

Rationale And Objectives: The aim of this study was to investigate whether a respiratory biofeedback system could increase navigator efficiency and maintain image quality compared to conventional respiratory-gated magnetic resonance coronary angiography (MRCA).

Materials And Methods: Eighteen healthy volunteers underwent MRCA using three different respiratory-gating protocols. A conventional expiratory free-breathing (FB) sequence was compared to two approaches using navigator echo biofeedback (NEB), a midinspiratory approach (NEBin) and an expiratory approach (NEBex).

Aortic wall thickness assessed by multidetector computed tomography as a predictor of coronary atherosclerosis.

Purpose of this study was the evaluation of the thoracic aortic wall thickness as a potential identifier of patients at increased risk for future cardiac events. Thoracic aortic wall thickness was measured with MDCT in 160 patients. The CT-scans were implemented as non-invasive coronary angiography studies.

The cisterna chyli: prevalence, characteristics and predisposing factors.

The purpose of this study was to determine the prevalence and characteristics of the cisterna chyli (CC) in a large 3,000-patient cohort and to identify potential predisposing factors for the development of a CC. Three thousand consecutive contrast-enhanced CT examinations (1,261 women, 1,739 men, mean age 61.0 years) of the chest and/or abdomen were included in this retrospective study.

MDCT of the abdomen.

Multi-detector row computed tomography (MDCT) enables fast and thin acquisition of the abdominal anatomy. This allows multi-pass multi-planar studies that can be obtained during defined circulatory phases. When bolus timing is adequate, arterial phases with high contrast levels provide "free lunch" CT angiographies eliminating the need for diagnostic angiographies in most cases.

MRI-based separation of congenital and acquired vertebrobasilar artery anomalies in ischemic stroke of the posterior circulation.

Background And Purpose: Stroke MRI protocols provide useful information about underlying vessel pathologies in the anterior circulation by means of intracranial time-of-flight angiography. However, these protocols mostly fail in the posterior circulation to differentiate between congenital variants and secondary thrombosis. Therefore, a high-resolution anatomic True Fast Imaging in Steady State Precession sequence, added to a commonly used stroke imaging protocol, was evaluated.

Electronic colon-cleansing for CT colonography: diagnostic performance.

Background: The purpose of this study was to evaluate whether an electronic-colonic-cleansing (ECC) algorithm is beneficial for the diagnostic performance compared to a CT colonography (CTC) evaluation without electronic cleansing in tagged datasets.

Methods: Two blinded readers evaluated CTC datasets from 79 patients with 153 colorectal polyps confirmed by optical colonoscopy. Cases were read in a randomized order with and without the use of electronic colon-cleansing software.

CT colonography: an update.

Computed tomographic (CT) colonography (CTC)--also known as "virtual colonoscopy"--was first described more than a decade ago. As advancements in scanner technology and three-dimensional (3D) postprocessing helped develop this method to mature into a potential option in screening for colorectal cancer, the fundamentals of the examination remained the same. It is a minimally invasive, CT-based procedure that simulates conventional colonoscopy using 2D and 3D computerized reconstructions.

Multiple gastrointestinal stromal tumors and bilateral pheochromocytoma in neurofibromatosis.

The coincidence of a gastrointestinal stromal tumor (GIST) and a neuroendocrine tumor (NET) in neurofibromatosis type 1 (NF1) is described only five times within the literature. We report on a 63 year old Caucasian female with the rare condition of neurofibromatosis type 1 coinciding with recurrent gastrointestinal stromal tumor plus bilateral pheochromocytoma (PCC). After a history of palpitations and dizziness that lasted for years, a left adrenal mass was detected by CT.

Comparison of manual and automated size measurements of lung metastases on MDCT images: potential influence on therapeutic decisions.

Purpose: The goal of this study was to evaluate the influence of automated measurement of diameter, area, and volume from chest CT scans on therapeutic decisions of lung nodules as compared to manual 2-D measurements.

Patients And Method: The retrospective study involved 25 patients with 75 lung metastases. Contrast enhanced CT scans (16 row) of the lung were performed three times during chemotherapy with a mean time interval of 67.

MR neurography with multiplanar reconstruction of 3D MRI datasets: an anatomical study and clinical applications.

Introduction: Extracranial MR neurography has so far mainly been used with 2D datasets. We investigated the use of 3D datasets for peripheral neurography of the sciatic nerve.

Methods: A total of 40 thighs (20 healthy volunteers) were examined with a coronally oriented magnetization-prepared rapid acquisition gradient echo sequence with isotropic voxels of 1 x 1 x 1 mm and a field of view of 500 mm.

Bowel preparation for CT-colonography: comparison of two different cleansing protocols.

Objective: Comparison of cleansing effects and colonic distension observed with two polyethyleneglycol-solution (PEG) containing bowel preparation techniques prior to CT-colonography (CTC).

Materials And Methods: One hundred and three patients that received CTC in our institution were retrospectively evaluated. Fifty-one patients received preparation 1 (BP1; based on a GoLytely formulation+bisacodyl), 52 preparation 2 (BP2; based on a NuLytely formulation+bisacodyl).

MDCT angiography of the spinal vasculature and the artery of Adamkiewicz.

Objective: The purpose of our study was to prospectively assess 40-MDCT technology in combination with adapted brain reconstruction algorithms to visualize the spinal vasculature, in particular the artery of Adamkiewicz and its anatomic variants.

Subjects And Methods: One hundred patients underwent contrast-enhanced MDCT of the thoracolumbar junction with collimation of 40 x 0.625 mm.

Spectral coronary multidetector computed tomography angiography: dual benefit by facilitating plaque characterization and enhancing lumen depiction.

Objective: To assess ex vivo specimens of atherosclerotic coronary arteries by dual energy (DE) multidetector computed tomography (MDCT) imaging, and to correlate depicted vessel lumen morphology and detected tissue characteristics with histopathologic analysis.

Methods: Coronary arteries were imaged on a 16-slice MDCT using a DE protocol consisting of a 90- and 140-kV scan. Coronary arteries were perfused with iodine- and gadolinium-based contrast agents.

Synergy of MDCT and cine MRI for the evaluation of cardiac motility.

Objective: The objective of our study was to validate the feasibility of the synergistic use of cardiac MR and CT data sets for ventricular motility analysis and to correlate measurement variability with underlying heart rate.

Subjects And Methods: Twenty patients underwent concurrent ECG-gated MDCT and MRI for evaluation of ventricular motility, expressed as ventricular wall thickening and motion. Initially, individual measurement repetition series were analyzed by determining intraobserver variability and detecting intraobserver bias related to heart rates.

CT colonography: comparison of a colon dissection display versus 3D endoluminal view for the detection of polyps.

The purpose of this study was to compare sensitivity, specificity, and postprocessing time of a colon dissection approach to regular 3D-endoluminal workup of computed tomography (CT) colonography for the detection of polypoid lesions. Twenty-one patients who had received conventional colonoscopy after CT colonography were selected; 18 patients had either colon polyps or colon cancer and three had no findings. CT colonography was performed using a 4-channel multi-detector-row (MDR) CT in ten cases and a 16-channel MDR-CT in 11 cases.

Enhancing gray-to-white matter contrast in 3T T1 spin-echo brain scans by optimizing flip angle.

Background And Purpose: Compared with MR imaging at 1.5T T1-weighted spin-echo imaging at 3T shows up with reduced gray-to-white matter contrast. The purpose of the present study was to show the effects of alterations of different flip angles as an easily accessible parameter to increase gray-to-white matter contrast.

Automatic determination of minimal cardiac motion phases for computed tomography imaging: initial experience.

Low motion phases for cardiac computed tomography reconstructions are currently detected manually in a user-dependent selection process which is often time consuming and suboptimal. The concept of motion maps was recently introduced to achieve automatic phase selection. This pilot study compared the accuracy of motion-map phase selection to that with manual iterative selection.

Noninvasive coronary angiography with multislice computed tomography.

Context: Multislice computed tomography (MSCT) has recently evolved as a modality for noninvasive coronary imaging.

Objective: To assess the accuracy and robustness of MSCT vs the criterion standard of invasive coronary angiography for detection of obstructive coronary artery disease.

Design, Setting, And Patients: Prospective, single-center study conducted in a referral center setting in Germany and enrolling 103 consecutive patients (mean age, 61.

Multi-detector row CT: is prospective electrocardiographic triggering improving the detection of small pulmonary tumors?

Rationale And Objectives: To compare prospectively ECG-triggered multi-detector row computed tomography (ECG-MDR-CT) and multi-detector row computed tomography (MDR-CT) without triggering for the detection of pulmonary tumors.

Materials And Methods: 100 patients with proven or suspected tumors were referred for CT of the lung for staging of lung metastases. First, a non-enhanced scan was performed using prospective ECG-triggering on a four-row multidetector helical CT scanner, followed by a contrast-enhanced scan without triggering.