Multiple Detector-row CT Research Articles

Multiple Detector-Row CT in Gastric Cancer Staging: Prospective Study

The aim of this study was to evaluate the accuracy of multiple detector computed tomography (MDCT) in the preoperative staging of gastric cancer, prospectively comparing CT findings with pathological findings at surgery, in a single-center study. A total of 19 consecutive patients with primary cancer recruited between March and July 2014 were submitted to preoperative MDCT staging according to a standard protocol. All diagnostic procedures were performed by dedicated radiologists who were unaware of the final pathological results. Subsequently, 16 patients underwent surgical treatment and 15 were finally included in the study. The primary tumor was detected at CT in all 15 cases. CT results for T staging were in agreement with pathological findings in 12 of 15 cases, with overall accuracy of 80%. Stage-specific sensibility was high for advanced stages (sensibility for T1, T3, and T4 resulted 60%, 85.7%, and 100%, respectively), while earlier stages showed higher specificity (specificity for T1, T3, and T4 resulted 100%, 75%, and 91.7%, respectively). Overall N staging accuracy was 86.7%, with 13 of 15 patients correctly staged. Stage-specific sensibility was 75% for N0 and 100% for N3, while specificity was 100% for N0 and lower for advanced stages. Accuracy for peritoneal involvement was 100%. Our findings show a good performance of the diagnostic protocol performed with MDCT tested in this study.

Advances in CT technology and application to pediatric imaging

The use of imaging in both hospital and non-hospital settings has expanded to more than 70 million CT procedures in the United States per year, with nearly 10% of procedures performed on children. The availability of multiple-row detector CT (MDCT) systems has played a large part in the wider usage of CT. This rapid increase in CT utilization combined with an increasing concern with regard to radiation exposure and associated risk demands the need for optimization of MDCT protocols. This manuscript will briefly discuss how technology has changed in regard to MDCT protocols, helping to reduce radiation dose in CT, especially in pediatric imaging.

High resolution spiral CT for determining the malignant potential of solitary pulmonary nodules: refining and testing the test

A solitary pulmonary nodule (SPN) may represent early stage lung cancer. Lung cancer is a devastating disease with an overall 5-year mortality rate of approximately 84% but with early detection and surgery as low as 47%. Currently a contrast-enhanced multiple-row detector CT (MDCT) scan is the first examination when evaluating patients with suspected lung cancer. To apply an additional high resolution CT (HRCT) to SPNs to test whether certain morphological characteristics are associated with malignancy, to assess the diagnostic accuracy of HRCT in the characterization of SPNs, and to address the reproducibility of all measures. Two hundred and thirteen participants with SPNs were included in a follow-up study. Blinded HRCT images were assessed with regard to margin risk categories (MRCs), calcification patterns and certain other characteristics and overall malignancy potential ratings (MPRs) were given. Morphological characteristics were tested against reference standard and ROC methodology was applied to assess diagnostic accuracy. Reproducibility was measured with Kappa statistics and 95% confidence intervals were computed for all results. Histopathology (90%) and CT follow-up (10%) were used as reference standard. MRCs (P < 0.001), calcification patterns (P = 0.003), and pleural retraction (P < 0.001) were all statistically significantly associated to malignancy. Reproducibility was moderate to substantial. Sensitivity, specificity, and overall diagnostic accuracy of HRCT were 98%, 23% and 87%, respectively. Reproducibility was substantial. Statistically significant associations between SPN MRCs, calcification patterns, pleural retraction and malignancy were found. HRCT yielded a very high sensitivity and a somewhat lower specificity for malignancy. Reproducibility was high.

High-resolution spiral CT for determining the malignant potential of solitary pulmonary nodules: refining and testing the test

BackgroundA solitary pulmonary nodule (SPN) may represent early stage lung cancer. Lung cancer is a devastating disease with an overall 5-year mortality rate of approximately 84% but with early det...

Angiografía por tomografía computarizada coronaria: indicaciones, adquisición de imágenes e interpretación

Intense scientific and clinical evaluation have brought about great improvements in cardiac CT. This is no longer merely an experimental technique, rather it has become a clinical application that is ready to fulfill its promise of replacing invasive cardiac catheterization in certain patient populations. Among the proven indications is the evaluation of patients with atypical chest pain, the morphological evaluation of the coronary arteries in cases of suspected congenital anomalies, and before surgical intervention, as well as the evaluation of coronary revascularizations. The use of CT angiography for the exhaustive evaluation of cardiac and non-cardiac pathology in patients with acute chest pain in the emergency department is currently being investigated. Because the heart is continuously moving, CT coronary angiography represents a greater technical challenge than other applications of CT. On the other hand, rapid technical development requires acquisition protocols to be adjusted constantly. However, users that know the general techniques of computed tomography can overcome these challenges. The aim of this article is to provide those interested and involved in CT angiography with a manual to enable them to follow our method step by step. We include considerations regarding the correct selection of patients, patient medication, radiological protection, contrast enhancement, acquisition and reconstruction parameters, image display, image analysis techniques, and the radiological report. Our recommendations are based on our experience, which runs from the evolution of multiple-row detector CT scanners for cardiac applications from its beginnings to the most modern presentations of advanced acquisition modalities, including dual-source CT, which we consider to be the precursor of this test in routine clinical practice.

Reproducible Simulation of Respiratory Motion in Porcine Lung Explants

To develop a model for exactly reproducible respiration motion simulations of animal lung explants inside an MR-compatible chest phantom. The materials included a piston pump and a flexible silicone reconstruction of a porcine diaphragm and were used in combination with an established MR-compatible chest phantom for porcine heart-lung preparations. The rhythmic inflation and deflation of the diaphragm at the bottom of the artificial thorax with water (1 - 1.5 L) induced lung tissue displacement resembling diaphragmatic breathing. This system was tested on five porcine heart-lung preparations using 1.5T MRI with transverse and coronal 3D-GRE (TR/TE = 3.63/1.58, 256 x 256 matrix, 350 mm FOV, 4 mm slices) and half Fourier T2-FSE (TR/TE = 545/29, 256 x 192, 350 mm, 6 mm) as well as multiple row detector CT (16 x 1 mm collimation, pitch 1.5, FOV 400 mm, 120 mAs) acquired at five fixed inspiration levels. Dynamic CT scans and coronal MRI with dynamic 2D-GRE and 2D-SS-GRE sequences (image frequencies of 10/sec and 3/sec, respectively) were acquired during continuous "breathing" (7/minute). The position of the piston pump was visually correlated with the respiratory motion visible through the transparent wall of the phantom and with dynamic displays of CT and MR images. An elastic body splines analysis of the respiratory motion was performed using CT data. Visual evaluation of MRI and CT showed three-dimensional movement of the lung tissue throughout the respiration cycle. Local tissue displacement inside the lung explants was documented with motion maps calculated from CT. The maximum displacement at the top of the diaphragm (mean 26.26 [SD 1.9] mm on CT and 27.16 [SD 1.5] mm on MRI, respectively [p = 0.25; Wilcoxon test]) was in the range of tidal breathing in human patients. The chest phantom with a diaphragmatic pump is a promising platform for multi-modality imaging studies of the effects of respiratory lung motion.

How to design injection protocols for multiple detector-row CT angiography (MDCTA)

The basis of the development of optimal injection protocols for multiple detector-row CT-angiography is knowledge of the physiological and pharmacokinetic principles of arterial enhancement. This article reviews the key rules of early arterial contrast medium dynamics: (1) Arterial enhancement is directly proportional to the iodine administration rate (iodine flux), and can be controlled by the injection flow rate and the iodine concentration of the contrast medium; (2) Arterial enhancement continuously increases over time with longer injection durations, due to the cumulative effects of bolus broadening and recirculation; (3) The strength of an individual's enhancement response to intravenously administered CM depends primarily on the patient's cardiac output and correlates inversely with body weight. In CTA, any of the following strategies can be employed alone, or in combination, to achieve adequate arterial enhancement in spite of short acquisition times: Increasing the injection rate, using higher concentration CM or increasing the injection duration (and scanning delay) relative to the scan time. Both injection volumes and flow rates should be adjusted to body weight, at least for patients < or =60 kg and > or =90kg BW. Rationally designed injection protocols based on physiological concepts allow optimal CM utilisation and take full advantage of the technical capabilities offered by modern MDCT scanners.

Multidetector row CT of the kidneys

In this article, the value of multiple detector-row computed tomography (MDCT) in renal applications is discussed, with emphasis on clinical uses. The superiority of application techniques of MDCT renders it one of the most distinguished modality in detection of congenital anomalies, tumors, transplants, trauma, and arterial diseases of the kidney.

MDCT of renal and mesenteric vessels.

Computed tomography angiography (CTA) with multiple detector-row CT (MDCT) has evolved into an established technique for non-invasive imaging of renal and mesenteric vessels. With adequate selection of acquisition parameters (thin collimation) high spatial-resolution volumetric data sets for subsequent 2D and 3D reformation can be acquired. Contrast medium (CM) injection parameters need to be adjusted to the acquisition speed of the scanners. Whereas fast acquisitions allow a reduction of total CM volume in the setting of CTA, this is not the case when CTA is combined with a second-phase abdominal MDCT acquisition for parenchymal (e.g., hepatic) imaging. Renal CTA is an accurate and reliable test for visualizing vascular anatomy and renal artery stenosis, and therefore a viable alternative to MRA in the assessment of patients with renovascular hypertension and in potential living related renal donors. CTA, combined with abdominal/parenchymal MDCT is a first-line diagnostic test in patients with suspected abdominal vascular emergencies, such as acute mesenteric ischemia, and an excellent tool to assess a wide variety of vascular abnormalities of the abdominal viscera.

Use of high-concentration contrast media in multiple-detector-row CT: principles and rationale

Contrast-medium-enhanced multiple-detector-row CT (MDCT) is a powerful technique for vascular and hepatic imaging. With increasingly faster acquisition speeds, which have become possible with latest 8- and 16-channel scanner systems, contrast medium delivery is becoming increasingly difficult. This article reviews the pharmacokinetic and physiologic principles of vascular and hepatic enhancement following the intravenous injection of iodinated contrast medium. The effects of user-selectable injection parameters, such as the injection rate, the injection duration, and the contrast medium concentration on arterial and parenchymal enhancement are elucidated. Equipped with this knowledge, rational injection strategies for CT angiographic protocols for scanners with different acquisition speeds are derived. Furthermore, injection and timing protocols, optimized for hepatic MDCT during the early arterial, late arterial, and parenchymal phases, are developed.

Improvement of parenchymal and vascular enhancement using saline flush and power injection for multiple-detector-row abdominal CT.

The aim of this study was to determine if a saline solution flush following low dose contrast material bolus improves parenchymal and vascular enhancement during abdominal multiple detector-row computed tomography (MDCT). Forty-one patients (24 men and 17 women; mean age 49 years, age range 27-86 years) underwent abdominal MDCT (collimation 4x5 mm, 15-mm table increment, reconstruction interval 5 mm, gantry rotation period 0.8 s) with a single- as well as with a double syringe power injector. Indication for examination were benign and malignant tumors and inflammatory diseases. Patients received 100 ml nonionic contrast material (300 mgI/ml) alone or pushed with 20 ml saline solution. Mean enhancement values for both protocols were measured in the liver, the spleen, the pancreas, the renal cortex, the portal vein, the inferior vena cava and the abdominal aorta. Double syringe power-injector protocol led to significantly higher parenchymal and vascular enhancement than single syringe power-injector protocol (p<0.05). The improvement in mean enhancement of the liver was 9 +/- 9 HU, of the spleen 8 +/- 10 HU, of the pancreas 7 +/- 9 HU, and of the renal cortex 8 +/- 20 HU. The improvement in mean enhancement of the portal vein was 10 +/- 17 HU of the inferior vena cava 8 +/- 13 HU and of the abdominal aorta 10 +/- 17 HU. The use of a double syringe power injector with saline flush following contrast material bolus significantly improves parenchymal and vascular enhancement during contrast-enhanced abdominal MDCT with low iodine doses.

Multiple detector-row CT angiography of the renal and mesenteric vessels

Computed tomography angiography (CTA) of the abdomen with multiple detector-row computed tomography (MD-CT) is an effective technique for minimally invasive imaging of the renal arteries and the visceral vasculature. This article reviews the clinical and technical aspects of MD-CT angiography in terms of image acquisition and reconstruction parameters, contrast medium application, and three-dimensional visualization with special attention to renal and mesenteric vascular imaging. Because of its high sensitivity to detect renal artery stenosis on the one hand, and because a normal renal CTA virtually excludes the presence of a significant renal artery stenosis on the other hand, renal CTA plays a useful role in the management of patients with suspected renovascular hypertension. Mesenteric CTA is a useful tool for visualizing normal vascular anatomy and its variants—particularly in the setting of organ transplantation. Vascular pathology, e.g. atherosclerotic disease (abdominal angina), or aneurysms of the visceral arteries are reliably assessed with CTA. Mesenteric CTA is an invaluable adjunct to abdominal CT in the setting of abdominal emergencies, because of its ability to detect the causes of acute intestinal ischemia (superior mesenteric artery embolism or thrombosis, superior mesenteric vein thrombosis). Accurate timing of the CTA acquisition and the subsequent parenchymal phase acquisition relative to the contrast medium transit time is critical to obtain excellent image quality in double-pass abdominal CT acquisitions.

Present and future trends in multiple detector-row CT applications: CT angiography.

Present and future trends in multiple detector-row CT applications: CT angiography.