MDCT Technique Research Articles

Evaluation of penetrating abdominal and pelvic trauma

Penetrating abdominal trauma comprises a wide variety of injuries that will manifest themselves at imaging depending on the distinct mechanism of injury. The use of computed tomography (CT) for hemodynamically stable victims of penetrating torso trauma continues to increase in clinical practice allowing more patients to undergo initial selective non-surgical management. High diagnostic accuracy in this setting helps patients avoid unnecessary surgical intervention and ultimately reduce morbidity, mortality and associated medical costs. This review will present the evidence and the controversies surrounding the imaging of patients with penetrating abdominopelvic injuries. Available protocols, current MDCT technique controversies, organ-specific injuries, and key MDCT findings requiring intervention in patients with penetrating abdominal and pelvic trauma are presented. In the hemodynamically stable patient, the radiologist will play a key role in the triage of these patients to operative or nonoperative management.

Assessment of Image Quality of Dual Energy 256 MDCT Technique Focused on keV Changes for MCA Stroke in Cerebral Angiography : Single Energy CT Standard Reference Mode

The purpose of this study was to evaluate the usefulness of cerebral angiography in each energy level by using dual energy technique in CT. Methods were performed on 15 DE images and SE images of CT angiography. For the analysis of images, mean value, standard deviation, SNR and CNR value were determined by setting ROI on MCA, brain parenchyma tissue, and back ground. As a result of concurrent visual evaluation with Likert 5 point scale, the clearest MCA image was confirmed at DE 40 keV and SE 120 kVp(p>0.05). The SNR value of the SE image was measured to be similar to the 40 keV energy level of the DE image. The low energy level image of 40 keV and 50 keV was measured with a high SNR and the contrast ratio was higher than that of the high energy image.

Diagnosis by 64-Row Multidetector Computed Tomography for Longitudinal Superficial Extension of Distal Cholangiocarcinoma

BackgroundThis study aimed to demonstrate the diagnostic ability of 64-row multidetector computed tomography (64-row MDCT) for longitudinal superficial extension of distal cholangiocarcinoma (LSEDC). MethodsTwenty-seven patients with distal cholangiocarcinoma (DC) underwent preoperative 64-row MDCT without drainage tubes. LSEDC was diagnosed using curved planar reconstruction images reconstructed from 64-row MDCT, which were compared with pathologic findings. ResultsLSEDC was observed in 13 patients (48%). Ten patients (37%) had enhancing nonthickened bile ducts extending continuously from the main tumor (type 1). These coincided with pathologic findings of high-grade dysplasia (HGD) in 90.0% of cases; that is, a positive predictive value (9/10). Fourteen patients (52%) had only wall thickening of the main tumor with or without enhancement (type 2). Four patients with HGD in this group were difficult to diagnose. Three patients (11%) had enhancing nonthickened bile ducts not in continuity with the main tumor (type 3). This finding revealed an inflammatory change instead of a carcinoma in the pathologic findings. The sensitivity and specificity of detecting HGD were 75% and 93% on the liver side, 33% and 100% on the duodenal side, respectively. Four patients (67%) with HGD on the liver side were overdiagnosed, and one patient (17%) was underdiagnosed. Most of the patients overdiagnosed on the liver side (3/4 or 75%) had drainage tubes inserted before the MDCT. ConclusionsFor DC patients without drainage tubes, the 64-row MDCT technique may be useful for diagnosing HGD depicted as LSEDC on the liver side but not as useful on the duodenal side.

Application of MDCT and post-processing in children with tracheal foreign body

Objective:To explore the clinical value of MDCT and post-processing in children with suspected foreign body in trachea.Method:Two hundred patients with suspected tracheal foreign body were treated with 64-slice spiral CT (MDCT) and simulated endoscopic imaging,then compared with seen in bronchoscopy; Compare the results of MDCT and post-processing with the coincidence of intraoperative findings.Result:One hundred and eighty-four cases of positive children were examined by MDCT postprocessing technique and bronchoscopy,179 cases were obstructed by exogenous foreign body,5 cases were phlegm thrombosis (endogenous foreign body) obstruction; 16 cases of children with no foreign body diagnosed by MDCT post-processing technique were also examined by bronchoscopy. The results showed that there was a foreign body in 1 case,and the foreign body was located in the pharyngeal cleft (watermelon spermoderm),and the remaining 15 cases had no foreign body. MDCT and post-treatment techniques for children with tracheal foreign body diagnosis of 99.4% sensitivity,specificity of 75%.There was no significant difference in the detection rate of foreign body between the two techniques of MDCT and post-processing technique and bronchoscopy (P>0.05). Examed by MDCT and postprocessing,we can understand the specific location and size of foreign body,nature,shape preoperatively.Conclusion:Although MDCT and post-processing techniques can not be used to treat tracheal foreign bodies,but the diagnostic rate of bronchial foreign bodies is comparable to that of bronchoscopy. We could apply MDCT examination and post processing before the bronchoscopy,for foreign body inhalation history is not clear,or suspected airway foreign body. We can improve the level of diagnosis and treatment through guiding the operation of bronchoscopy focus.

Nontraumatic large bowel perforation: spectrum of etiologies and CT findings.

Large bowel perforation is an abdominal emergency that results from a wide range of etiologies. Computed tomography is the most reliable modality in detecting the site of large bowel perforation. The diagnosis is made by identifying direct CT findings such as extraluminal gas or contrast and discontinuity along the bowel wall. Indirect CT findings can help support the diagnosis, and include bowel wall thickening, pericolic fat stranding, abnormal bowel wall enhancement, abscess, and a feculent collection adjacent to the bowel. Common etiologies that cause large bowel perforation are colon cancer, foreign body aspiration, stercoral colitis, diverticulitis, ischemia, inflammatory and infectious colitides, and various iatrogenic causes. Recognizing a large bowel perforation on CT can be difficult at times, and there are various entities that may be misinterpreted as a colonic perforation. The purpose of this article is to outline the MDCT technique used for evaluation of suspected colorectal perforation, discuss relevant imaging findings, review common etiologies, and point out potential pitfalls in making the diagnosis of large bowel perforation.

MDCT and MRI of the ampulla of Vater. Part I: technique optimization, normal anatomy, and epithelial neoplasms.

The purpose of this two-part article is to review the cross-sectional anatomy of the ampulla and periampullary region, to propose novel and optimized MDCT and MRI techniques that allow accurate evaluation of the ampulla of Vater, and to summarize the cross-sectional imaging features of benign and malignant ampullary conditions. In this first part, we will review the normal anatomy of the ampullary region, provide suggestions on how to optimize evaluation of the ampullary region by MDCT and MRI, and review the imaging features of select epithelial neoplasms of the ampulla. Familiarity with the normal ampullary anatomy and the pathologic conditions involving the ampulla, as well as the use of optimized MDCT and MRI techniques, may improve the diagnostic accuracy of radiologists facing ampullary abnormalities.

MDCT and MRI of the ampulla of Vater. Part II: non-epithelial neoplasms, benign ampullary disorders, and pitfalls.

The purpose of this two-part article is to review the cross-sectional imaging features of benign and malignant ampullary conditions with endoscopic and histopathologic correlation and to present the most common pitfalls in the evaluation of the ampulla. In this part, we will review the mesenchymal and secondary neoplasms of the ampulla, a vast array of benign ampullary conditions, causes of bulging papilla, and pitfalls. Familiarity with ampullary pathologic conditions and pitfalls, as well as the use of optimized MDCT and MRI techniques, may improve the diagnostic accuracy of radiologists facing ampullary abnormalities.

SU-E-I-28: Introduction and Investigation of Effective Diameter Ratios as a New Patient Size Metric for Use in CT

Purpose: To introduce and investigate effective diameter ratios as a new patient metric for use in computed tomography protocol selection as a supplement to patient-specific size parameter data. Methods: The metrics of outer effective diameter and inner effective diameter were measured for 7 post-mortem subjects scanned with a standardized chest/abdomen/pelvis (CAP) protocol on a 320-slice MDCT scanner. The outer effective diameter was calculated by obtaining the anterior/posterior and lateral dimensions of the imaged anatomy at the middle of the scan range using Effective Diameter= SQRT(AP height*Lat Width). The inner effective diameter was calculated with the same equation using the AP and Lat dimensions of the anatomy excluding the adipose tissue. The ratio of outer to inner effective diameter was calculated for each subject. A relationship to BMI, weight, and CTDI conversion coefficients was investigated. Results: For the largest subject with BMI of 43.85 kg/m2 and weight of 255 lbs the diameter ratio was calculated as 1.33. For the second largest subject with BMI of 33.5 kg/m2 and weight of 192.4 lbs the diameter ratio was measured as 1.43, indicating a larger percentage of adipose tissue in the second largest subject’s anatomical composition. For the smallest subject at BMI of 17.4more » kg/m2 and weight of 86 lbs a similar tissue composition was indicated as a subject with BMI of 24.2 kg/m2 and weight of 136 lbs as they had the same diameter ratios of 1.11. Conclusion: The diameter ratio proves to contain information about anatomical composition that the BMI and weight alone do not. The utility of this metric is still being examined but could prove useful for determining MDCT techniques and for giving a more in depth detail of the composition of a patient’s body habitus.« less

The role of multidetector computed tomography and magnetic resonance recent imaging techniques in the evaluation of intra-conal orbital lesions

ObjectiveThe purpose of our study was to assess the role of multi-detector computed tomography and magnetic resonance recent imaging techniques in the evaluation of intra-conal orbital lesions. Subjects and methods30 patients presented to the Ophthalmic and Radiology Departments at El-Minia University Hospital and El Minia Oncology Center with clinical diagnosis of visual loss and proptosis. They presented during the period from June 2012 to October 2013. Their ages range from 5 to 73years. All patients subjected to MDCT and MRI. Also, contrast injection was injected on some cases. 24 patients were subjected to surgery and histopathology to confirm the radiological diagnosis. ResultsA total of 30 patients were included (their mean age 26years). 8 lesions were diagnosed inflammatory in nature (4 were orbital abscess and 4 were idiopathic orbital inflammatory disease i.e. pseudo tumors). 10 lesions were diagnosed as vascular lesions (2 lesions were carotid cavernous fistula and 8 lesions were cavernous hemangiomas). 6 lesions were diagnosed as optic nerve gliomas and other 6 lesions were diagnosed optic nerve sheath meningiomas. ConclusionThe use of MDCT and MRI recent techniques are mandatory for accurate diagnosis of the nature of intra-conal orbital mass lesions.

Clinical impact of an adaptive statistical iterative reconstruction algorithm for detection of hypervascular liver tumours using a low tube voltage, high tube current MDCT technique

To investigate the impact of an adaptive statistical iterative reconstruction (ASiR) algorithm on diagnostic accuracy and confidence for the diagnosis of hypervascular liver tumours, as well as the reader's perception of image quality, using a low tube voltage (80 kVp), high tube current computed tomography (CT) technique. Forty patients (29 men, 11 women) with 65 hypervascular liver tumours underwent dual energy CT. The 80 kV set of the dual energy acquisition was reconstructed with standard filtered backprojection (FBP) and ASiR at different blending levels. Lesion contrast-to-noise ratio (CNR), reader's confidence for lesion detection and characterisation, and reader's evaluation of image quality were recorded. ASiR yielded significantly higher CNR values compared with FBP (P < 0.0001 for all comparisons). Reader's perception of lesion conspicuity and confidence in the diagnosis of malignancy were also higher with 60 % and 80 % ASiR, compared with FBP (P = 0.01 and < 0.001, respectively). Compared with FBP, ASiR yielded nearly significantly lower specificity for lesion detection and a substantial decrease in the reader's perception of image quality. Compared with the standard FBP algorithm, ASiR significantly improves conspicuity of hypervascular liver lesions. This improvement may come at the cost of decreased specificity and reader's perception of image quality.

A New MDCT Technique for the Detection and Anatomical Exploration of Urogenital Fistulas

We tested a new MDCT technical protocol, combining i.v. and intravesical positive contrast agent and intravaginal neutral contrast agent, that optimizes exploration of urogenital fistulas. We examined three patients (four CT examinations in total) with this technique and proved that a preexisting subtle ureterovaginal fistula that was under treatment was still present, though clinically silent. The proposed MDCT examination protocol provides important information to help detect subtle urogenital fistulas.

Incidence of Pulmonary Embolus and Rate of Nondiagnostic CTs PE/DVT Studies in Soldiers With Polytrauma

PURPOSE: To determine the incidence of pulmonary embolism (PE) in wounded soldiers compared to the general population with clinical concern for PE with a goal to improve specificity and sensitivity of the current MDCT techniques and to establish guidelines to manage high risk population with specific protocols.

Cardiac Valve Disease: Spectrum of Findings on Cardiac 64-MDCT

Recent studies have established that cardiac MDCT generates high-quality images of the cardiac valves. Images are acquired during a single breath-hold (inspiration) after the injection of iodinated contrast material (5 mL/s) followed by a saline bolus chaser. Incremental data sets are then reconstructed throughout the R-R interval, and after transfer to a workstation, specialized software combines data sets sequentially to generate cine loops of the heart throughout the cardiac cycle. The purpose of this article is to describe the cardiac MDCT techniques allowing optimal cardiac valve depiction and to illustrate the MDCT appearances of the most important valve diseases. Cardiac MDCT provides an excellent imaging method for illustrating cardiac valve disease. Radiologists should be aware of the various appearances of the common and most important cardiac valve diseases on cardiac MDCT.

MDCT technique and imaging findings of urinary stone disease: an expanded review

Unenhanced computed tomography (CT) is currently being widely used for the evaluation of patients presenting with acute flank pain. A variety of primary and secondary findings detected on unenhanced CT contribute not only to the diagnosis but also to the treatment plan. This review includes primary and secondary multidetector CT imaging findings of urinary stone disease, potential pitfalls with exquisite images of sample cases, and a brief review of radiation dose reduction and contrast administration strategies.