Diagnostic Accuracy For Detection Research Articles

Diagnostic Accuracy of Ascites Fluid Gross Appearance in Detection of Spontaneous Bacterial Peritonitis.

Spontaneous bacterial peritonitis (SBP) as a monomicrobial infection of ascites fluid is one of the most important causes of morbidity and mortality in cirrhotic patients. This study was aimed to determine the diagnostic accuracy of ascites fluid color in detection of SBP in cirrhotic cases referred to the emergency department. Cirrhotic patients referred to the ED for the paracentesis of ascites fluid were enrolled. For all studied patients, the results of laboratory analysis and gross appearance of ascites fluid registered and reviewed by two emergency medicine specialists. The sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ration of the ascites fluid gross appearance in detection of SBP were measured with 95% confidence interval. The present project was performed in 80 cirrhotic patients with ascites (52.5 female). The mean of the subjects' age was 56.25±12.21 years (35-81). Laboratory findings revealed SBP in 23 (29%) cases. Fifty nine (73%) cases had transparent ascites fluid appearance of whom 17 (29%) ones suffered from SBP. From 21 (26%) cases with opaque ascites appearance, 15 (71%) had SBP. The sensitivity and specificity of the ascites fluid appearance in detection of SBP were 46.88% (Cl: 30.87-63.55) and 87.50% (95% Cl: 75.3-94.14), respectively. It seems that the gross appearance of ascites fluid had poor diagnostic accuracy in detection of SBP and considering its low sensitivity, it could not be used as a good screening tool for this propose.

Diagnostic performance of Multislice Computed Tomography in evaluation of coronary artery bypass grafts in diabetic and non-diabetic patients

Objectives We sought to evaluate the diagnostic accuracy of noninvasive dual-source multi-slice computed tomography (MSCT) angiography in the assessment of graft patency and degree of stenosis in patients after coronary artery bypass grafting (CABG). Background Assessment of bypass grafts body and their anastomotic sites by invasive coronary angiography have a risk of potentially life-threatening complications and often require extra procedure time, contrast load, and radiation exposure. Methods 64-dual-source MSCT was performed to 51 (49 men, mean age 58.6 ± 8 years, range from 38 to 76) post-CABG symptomatic patients. Control of heart rate was done with oral beta blockers, sublingual nitrates was given 2-3 min before the scan. Mean interval between CABG surgery and MSCT was 73.41 ± 65.84 (range 3 to 252) months. Mean heart rate during scanning was 62.5 ± 13.2 (range 52–72) beats/min. Ninety-four percent of patients had both arterial and venous grafts. A total of 142 graft body and 142 anastomotic sites were analyzed. Two grafts body and 4 anastomotic sites were excluded because they were non-evaluable by MSCT. A semi-quantitative assessment of the graft stenosis severity was done according to the recommendation of the Society of Cardiovascular Computed Tomography (SCCT) A significant stenosis was defined as equal to or >70%, moderate stenosis 40–69% and mild Results The diagnostic accuracy of MSCT for the detection or exclusion of significant stenosis in grafts body and their anastomotic sites was 99.28%, sensitivity, specificity, positive and negative predictive values were 97.75%, 100%, 100%, 98.95%. The diagnostic accuracy for detection of degree of graft stenosis (mild, moderate, severe or occluded) was 97.18%. Conclusion Noninvasive MSCT angiography is an excellent tool for evaluating patency or degree of stenosis of bypass grafts body and their anastomotic sites in post-CABG patients.

Three-Dimensional Ultrasound in Diagnosis of Adenomyosis: Histologic Correlation With Ultrasound Targeted Biopsies of the Uterus

Study ObjectiveTo evaluate the accuracy of 3-dimensional transvaginal sonography (3D TVS) in the diagnosis of adenomyosis by correlating adenomyosis-induced morphologic alterations in the myometrium and the junctional zone (JZ) with histopathologic features of targeted biopsy specimens of the uterus. DesignProspective study (Canadian Task force classification II-2). SettingPrivate practice associated with a university program. PatientsSymptomatic premenopausal women scheduled to undergo hysterectomy because of benign conditions. InterventionsPatients underwent preoperative 3D TVS of the uterus to evaluate alterations to the JZ, to measure the smallest (JZmin) and largest (JZmax) JZ thickness, and to assess for the presence of myometrial heterogeneous and cystic areas, hyperechoic striations, and asymmetry of the myometrial wall. Localization and position of the lesions in the myometrial wall were accurately recorded. Results of the sonographic features were correlated with the histopathologic findings of the ultrasound-based targeted biopsy specimens of the uterus. Measurements and Main ResultsThe study included 54 symptomatic premenopausal women with a mean age of 42.1 years. Of these, 12 had previously undergone endometrial ablation and 10 were receiving medical therapy, and these patients were considered separately for the statistical analysis. The prevalence of adenomyosis at histology was 66.6% (36/54). Of 32 patients who had received no previous treatment, 26 had adenomyosis on the targeted biopsy specimens of the myometrium. 3D TVS features of adenomyosis with the best specificity (83%) and positive predictive values were JZmax ≥8 mm, myometrial asymmetry, and hypoechoic striation. When we considered the presence of at least 2 of the described ultrasound features for the diagnosis of adenomyosis, accuracy was 90% (sensitivity, 92%; specificity, 83%; positive predictive value, 99%; and negative predictive value, 71%). Diagnostic accuracy was decreased to 50% in patients who had previously undergone endometrial ablation, and to 60% in patients receiving medical therapy. Conclusion3D TVS demonstrates high diagnostic accuracy in detection of site and position of adenomyosis in the uterine walls. Endometrial ablation and medical therapy alter the appearance of the JZ, compromising the accuracy of 3D US in enabling the diagnosis of adenomyosis.

Low latency iterative reconstruction of first pass stress cardiac perfusion with physiological stress using graphical processing unit

Background Cardiac MR perfusion has been shown to provide high diagnostic accuracy in detection of the coronary artery disease [1]. We have recently installed an MR-compatible supine bicycle mounted on the scanner table, which allows performing CMR perfusion immediately after physiologic stress. However, patients are unable to sustain a breathold after physical exercise, limiting the choice of acceleration techniques such as k-t approaches. Additionally, due to subject motion during exercise, coil sensitivity map are inaccurate resulting in imaging artifacts in conventional parallel imaging reconstruction. Compressed sensing (CS) is an alternative acceleration technique that enables high acceleration even without exploiting temporal dimension or need for coil maps. However, iterative CS reconstruction of randomly undersampled k-space is lengthy, performed off-line and is not usually integrated into the workflow of a clinical scan which requires viewing and initial assessment on the scanner console and storing the clinical images on the hospital PACS system. In this proposal, we aim to develop an accelerated iterative CS reconstruction workflow for reconstruction of CS acquired perfusion data using physical stress perfusion.

Diffusion weighted imaging for quantification of liver fibrosis in patients using normalized apparent diffusion coefficient values at 3.0 T MR

Objective The purpose of this study is to discuss the diagnostic accuracy of nornalized liver ADC using the spleen and renal cortex as reference organs for the diagnosis of liver fibrosis.Methods Forty three patients with liver disease (chronic liver disease group) at compensated stage and 10 healthy volunteers (control group) were retrospectively assessed with diffusion-weighted imaging at a 3.0 T MR unit.Liver ADC,spleen ADC,renal ADC and normalized ADC (defined as the ratio of liver ADC to spleen ADC or renal cortex ADC,S-ADC and R-ADC for short) were measured in patients stratified by fibrosis stage.Spearman analysis was used to see the correlation between fibrosis stages and ADC,one-way ANOVA was used to compare the ADCs in different fibrosis stages.Logistic regression analysis was used to determine the performance of ADC for prediction of liver fibrosis,and show the area under the curve ( AUC),sensitivity and specificity choosing the optimal cutoff value that maximized the Youden index.Results Ten volunteers belonged to SO stage.From SO to S4 stage,there were 2,5,9,12 and 15 patients,correspondingly,liver ADCwere (1.37±0.13) ×10-3,(1.33±0.16) ×10 -3,(1.17±0.16) ×10-3,(1.23±0.14) ×10-3and ( 1.12 ±0.11 ) × 10-3mm2/s,S-ADC were 1.86 ±0.18,1.68 ±0.12,1.34 ±0.14,1.48 ±0.15 and 1.34±0.10,R-ADC were 0.71 ±0.08,0.68 ±0.12,0.61 ±0.09,0.64 ±0.11 and 0.60 ±0.08respectively,and the differences among them were significant ( F =6.48,18.70 and 3.04,P ＜0.05 ).The correlation between fibrosis stage and S-ADC was stronger than between fibrosis stage and liver ADC,R-ADC (r =- 0.71,- 0.51,- 0.41 ;P ＜ 0.01 ).S-ADC was superior to liver ADC and R-ADC for detection of S2,S3 and S4 fibrosis stage (Youden index:0.91,0.58,and 0.59).Conclusion Spleen normalized liver ADC improves diagnostic accuracy for detection of liver fibrosis than liver ADC and renal normalized liver ADC. Key words: Liver cirrhosis; Magnetic resonance imaging; Comparative study

Pulmonary MDCT Angiography: Value of Multiplanar Reformatted Images in Detecting Pulmonary Embolism in Children

The purpose of this study was to determine whether the use of multiplanar reformatted (MPR) MDCT images in the diagnosis of pulmonary embolism (PE) in children by faculty pediatric radiologists and radiology residents affects reader performance parameters and adds diagnostic value compared with the use of axial MDCT images alone. This retrospective study was conducted with the images of 60 children (28 boys, 32 girls; mean age, 14.7 ± 3.5 years; range, 3.2-18 years) who consecutively underwent pulmonary CT angiography (CTA) for clinically suspected PE. Two faculty pediatric radiologists and two radiology residents independently reviewed images from each study initially using only axial MDCT images and later using MPR MDCT images in any x-, y-, or z-axis. Diagnostic accuracy, confidence level (1-5 ordinal scale), and interpretation time for MPR MDCT images were compared with those for axial MDCT images by use of the McNemar test and paired Student t test. The kappa coefficient was calculated to assess interobserver agreement. Diagnostic accuracy was compared between faculty pediatric radiologists and radiology residents by logistic regression analysis, and confidence level, interpretation time, and added diagnostic value were evaluated by analysis of variance. Nine of 60 pulmonary CTA studies (15%) were found to show PE. Diagnostic accuracy in detection of PE ranged from 91.7% to 100% (mean, 96.7%) with no significant differences between axial and MPR MDCT images (McNemar test for matched binary pairs, p > 0.50 for each reviewer). Logistic regression showed no significant difference between faculty pediatric radiologists and radiology residents in diagnostic accuracy in detection of PE on axial MDCT images (p = 0.48) or MPR MDCT images (p = 0.24). Confidence level and interobserver agreement were significantly higher and average interpretation time was longer in the evaluation of PE with MPR MDCT images than with axial MDCT images for all reviewers (p < 0.001). Compared with faculty pediatric radiologists, radiology residents had significantly greater increases in confidence level, interobserver agreement, interpretation time, and added diagnostic value using MPR MDCT images than they did using axial MDCT images to diagnose PE (p < 0.001). Use of MPR MDCT images for pulmonary CTA in the diagnosis of PE in children significantly increases confidence, interobserver agreement, and interpretation time among faculty pediatric radiologists and radiology residents. Because use of MPR MDCT images results in significantly greater improvements in reading parameters for residents than for faculty members, the routine use of this technique by trainees should be encouraged.

Abstract 8702: Assessment of Coronary Artery Disease by Contraction Front Mapping Analysis with Real Time Three-dimensional Stress Echocardiography with Adenosine: A Comparison with Thallium Scintigraphy

Background: Stress echo with adenosine is not routinely used for the assessment of coronary artery disease (CAD) because of insufficient accuracy. Visual estimation of dyssynchrony with 2-D echo is often difficult because delays &lt;70 ms cannot be detected with human eye. Contraction front mapping (CFM) constructed by real time 3-D echocardiography (RT3DE, ACUSON SC2000) with frame rate of 40 fps provides time-volume analysis for left ventricular (LV) volume, and enables us to assess LV dyssynchrony in only one heart beat. Thus, we evaluated usefulness of stress RT3DE for the detection of CAD. Methods : We performed scintigraphy and CFM at rest and stress with adenosine before angiography in 35 patients with suspected CAD. CFM can automatically divide LV into 16 segments, detect dyssynchrony and provide systolic dyssynchrony index (SDI) from the dispersion of time to minimum (min) regional volume for all 16 segments (average SDI) and maximum (max) dispersion of time to min regional volume (max SDI). Coronary angiography was served as a gold standard. Results : Images suitable for analysis were 34 (Figure). Heart rate and LV ejection fraction were increased at stress by 12% and 11% respectively. The prevalence of CAD was 76%. Diagnostic accuracy (88% for echo vs. 87% for scintigraphy), sensitivity (88% vs. 88%) and specificity (88% vs.85%) for the detection of CAD were similar between stress RT3DE and sintigraphy. There was no significant difference in the ability to detect single- or multi-vessel disease between RT3DE and scintigraphy. Although average SDI was similar at rest and at stress (6.6±4.0% vs.7.2±4.0%) max SDI was significantly increased at stress (22±10% vs. 18±8%, p&lt;0.05). Conclusion: CFM constructed by stress RT3DE as a promising technique to quantify LV dyssynchrony in only one heart beat confers similar diagnostic accuracy in detection of CAD to scintigraphy and may be useful in the clinical setting for the evaluation of patients with suspected CAD.

Radiographic Assessment of Proximal Caries: A Comparison between Film-based and Dexis Digital Imaging Systems

This study compared Kodak Ektaspeed film and Dexis digital imaging systems for their diagnostic accuracy in detection of proximal caries in 210 proximal surfaces from 105 extracted human teeth (20 premolars and 85 molars), 129 of which were carious. Ground teeth were evaluated histologically. The images were assessed by an observer. ANOVA revealed that groups differ in scoring patterns with f-value of 26.72 and p < 0.01. The mean caries score by histologic assessment was significantly (p < 0.01) more when compared with the scores obtained by conventional and Dexis digital radiographic methods. The mean score for conventional radiographic method was slightly more than Dexis digital radiographic method, but the difference was statistically insignificant (p < 0.05). Both the radiographic methods were less accurate in detecting proximal caries confined to enamel, but as the lesion depth was increased to dentin, the rate of caries detection increased dramatically. It was concluded that both conventional and Dexis digital radiographic methods under estimated caries depth when compared with histologic method. Lastly, conventional film radiographs and Dexis digital radiographs did not perform significantly different from each other in the detection of caries.

Intraindividual comparison of gadolinium- and iodine-enhanced 64-slice multidetector CT pulmonary angiography for the detection of pulmonary embolism in a porcine model

This study is an evaluation of the diagnostic accuracy of gadolinium-enhanced computed tomography pulmonary angiography (CTPA) for the detection of pulmonary embolism (PE) in comparison with iodine-enhanced CTPA. PE was induced in five anesthetized pigs by administration of blood clots through an 11-F catheter inside the jugular vein. Animals underwent CTPA in breathhold with i.v. bolus injection of 50ml gadopentetate dimeglumine (0.4mmol/kg, 4ml/s). Subsequently, CTPA was performed using the same imaging parameters but under administration of 70ml nonionic iodinated contrast material (400mg/ml, 4ml/s). All images were reconstructed with 1mm slice thickness. A consensus readout of the iodium-enhanced CTPAs by both radiologists served as reference standard. Gadolinium-enhanced CTPAs were evaluated independently by two experienced radiologists, and differences in detection rate between both contrast agents were assessed on a per embolus basis using the Wilcoxon signed-rank test. Interobserver agreement was determined by calculation of қ values. PE was diagnosed independently by both readers in all five pigs by the use of gadolinium-enhanced CTPA. Out of 60 pulmonary emboli detected in the iodine-enhanced scans, 47 (78.3%; reader 1) and 44 (62.8%; reader 2) emboli were detected by the use of gadolinium. All 13 (100%) emboli in lobar arteries (by both readers) and 26 (reader 1) and 25 (reader 2) out of 27 emboli (96.3% and 92.6%) in segmental arteries were detected by the use of the gadolinium-enhanced CTPA. In subsegmental arteries, only 8 (40%; reader 1) and 6 (30%; reader 2) out of 20 emboli were detected by the gadolinium-enhanced CTPA. By comparing both scans on a per vessel basis (Wilcoxon test), Gd-enhanced CTPA was significantly inferior in emboli detection on subsegmental level (P < 0.0001). The interobserver agreement was excellent on lobar and segmental level (қ = 1.0 and 0.93, respectively), whereas readers only reached moderate agreement for PE evaluation on subsegmental level (қ = 0.56). Compared to conventional CTPA with iodinated contrast media, gadolinium-based contrast agents achieve an equivalent diagnostic accuracy in detection of PE down to segmental level. Gadolinium-enhanced CTPA may be considered as an alternative for the diagnostic workup of acute pulmonary embolism in patients with contraindications to iodinated contrast agents.

Prospective respiratory-triggered 64-slice CT pulmonary angiography for detection of pulmonary embolism—a feasibility study in a porcine model

The objective of this study is to investigate the feasibility of prospectively respiratory-triggered CT pulmonary angiography (CTPA) for detection of pulmonary embolism (PE) in a porcine model. A free-breathing respiratory-triggered multislice CTPA (120 kV, 140 mAs(eff), 2.5-mm slice thickness) and two CTPA in breath-hold technique (120 kV, 140 mAs(eff.) and 250mAs(eff), 1-mm and 3-mm image reconstruction) were performed in six pigs with pulmonary embolism. Diagnostic accuracy was computed, and differences in detection rates between both techniques were assessed on a per-embolus basis with the Wilcoxon test. Thin-sliced 1-mm images, acquired with 250mAs(eff), served as the standard of reference. Respiratory-triggered CTPA reached high diagnostic accuracy in detection of lobar and segmental PE equal to the results with the breath-hold technique (p > 0.05). For detection of subsegmental emboli, standard breath-hold techniques performed significantly better than respiratory-gated CTPA (sensitivity, 68.3% versus 24.4%; p < 0.05). Free-breathing respiratory-triggered CTPA is feasible for detection of lobar and segmental PE, with diagnostic accuracy equivalent to that of a standard CTPA in breath-hold. Although this technique is not recommended for assessment of emboli in the subsegmental vasculature, prospective respiratory-triggered CTPA may be of added value in patients who cannot hold their breath appropriately for CTPA scanning.

High-Sensitivity Cardiac Troponin Assays: What Analytical and Clinical Issues Need to Be Addressed before Introduction into Clinical Practice?

The guidelines of the Global Task Force for the Universal Definition of Myocardial Infarction (MI)1 and the complementary laboratory medicine practice guidelines of the National Academy of Clinical Biochemistry (NACB), both published in 2007, established cardiac troponin (cTn) as the standard biomarker for the diagnosis of MI. Ongoing improvements in technology over the past several years have advanced the analytical detection of low concentrations of cTn (I and T) in blood, serum, and plasma. “Contemporary” assays demonstrate excellent diagnostic accuracy for detection of MI by using the recommended 99th percentile concentration as the medical decision cutoff value in specimens obtained at presentation. Optimal accuracy is seen with these assays in samples obtained 6 or more hours after presentation. However, there are 2 important biomarker issues mentioned in these guidelines that will be critical in defining the next and possibly final generation of high-sensitivity (hs) cTn assays. (1) In both guidelines, total assay imprecision is recommended but not required to be ≤10% at the 99th percentile. As previously shown and discussed in the literature, cTn assay imprecision ≤20% CV at the 99th percentile value does not lead to substantial increases in false-positive or -negative misclassifications. (2) Whereas study of a normal reference population is advocated in both guidelines for calculation of the 99th percentile before assay implementation in clinical practice, the specifications of that population (age, sex, ethnicity, race) and the number of individuals that should be included in the “normal” group have not been clearly stipulated. An opinion paper recently published in this journal suggested that hs-cTn assays need to have a total imprecision ≤10% at the 99th percentile and that >95% of apparently healthy subjects need to have measurable concentrations for the assay to be “guideline acceptable.” An assay with an imprecision between >10% and ≤20% was deemed …

The role of PET/CT in detection of gastric cancer recurrence

BackgroundIn the course of surveillance of gastric cancer recurrence after curative resection, contrast CT scan is used in general. However, new findings from CT scan are not always confirmatory for the recurrence. In this case, we usually use short-term follow up strategy or therapeutic intervention with clinical decision. Recently, the use of fusion Positron Emission Tomography/Computed Tomography (PET/CT) is increasing. The purpose of this study is to evaluate the efficacy and usefulness of PET/CT for detecting recurrence of gastric cancer after curative resection.MethodsFifty two patients who received curative resection of gastric cancer and had undergone PET/CT and contrast CT for surveillance of recurrence until Dec 2006 in Seoul National University Hospital were analyzed retrospectively. Recurrence of gastric cancer was validated by histologic confirmation (n = 17) or serial contrast CT follow up with at least 5 month interval (n = 35). McNemar's test and Fisher's exact test were used to evaluate sensitivity and specificity of PET/CT and contrast CT.ResultsOf 52 patients, 38 patients were confirmed as recurrence. The sensitivity was 68.4% (26/38) for PET/CT and 89.4% (34/38) for contrast CT (p = 0.057). The specificity was 71.4% (10/14) and 64.2% (9/14), respectively (p = 1.0). In terms of the recurred sites, the sensitivity and specificity of PET/CT were similar to those of contrast CT in all sites except peritoneum. Contrast CT was more sensitive than PET/CT (p = 0.039) for detecting peritoneal seeding. Additional PET/CT on contrast CT showed no further increase of positive predictive value regardless of sites. Among 13 patients whose image findings between two methods were discordant and tissue confirmation was difficult, the treatment decision was made in 7 patients based on PET/CT, showing the final diagnostic accuracy of 42.8% (3/7).ConclusionPET/CT was as sensitive and specific as contrast CT in detection of recurred gastric cancer except peritoneal seeding. However, additional PET/CT on contrast CT did not increase diagnostic accuracy in detection of recurred gastric cancer. Further studies are warranted to validate the role of PET/CT in detection of gastric cancer recurrence.

Multi-detector computerized tomography angiography for evaluation of acute chest pain — A meta analysis and systematic review of literature

Background Evaluation of pain localized to the chest in the emergency room is, challenging, time-consuming, costly, and often inconclusive. Available research, though limited, suggests a role for MDCTA in the evaluation of patients with acute chest pain of low to intermediate risk, for identifying and excluding ACSs during the initial emergency department evaluation. Accordingly, our aim was to conduct a meta-analysis to assess the diagnostic accuracy of MDCTA in this setting. Methods We included all studies that compared MDCTA with either coronary angiography or standard of care for early and accurate triage of patients presenting with acute chest pain. Published studies were identified by searches of the Pubmed, Ovid and Google scholar databases as well as hand searches of selected references. Data were extracted independently by two reviewers. Included studies were evaluated for heterogeneity. Meta-analysis was performed at patient level using a random-effects model. Results 16 studies totaling 1119 patients were included in the current meta-analysis: one randomized trial, one retrospective analysis and fourteen prospective cohort studies. Pooled DOR was 190.80 (95%CI, 102.94–353.65). The pooled sensitivity and specificity were 0.96 (95%CI, 0.93–0.98) and 0.92(95%CI, 0.89–0.94) respectively. The pooled NLR and PLR were 0.09 (95%CI, 0.06–0.14) and 10.12 (95%CI, 6.73–15.22). Conclusion MDCTA has an excellent diagnostic accuracy in detection of significant coronary artery stenosis in patients with acute chest pain. This diagnostic accuracy of MDCTA has a potential for rapid triage of patients in the ED, with acute chest pain of low to intermediate risk of acute coronary syndrome, to rule out significant epicardial stenosis as the etiology of chest pain.

Myocardial infarction imaging by CT

Several recent studies have demonstrated that cardiac CT can accurately diagnose both acute and chronic areas of myocardial infarction. Furthermore, when performed in the setting of acute infarction, CT can be helpful in predicting the degree of functional recovery. Given that such findings can have important clinical implications, it is necessary to integrate the assessment of myocardial perfusion, and when available, myocardial function into the routine evaluation of contrast-enhanced cardiac CT. This article presents an overview of prior studies examining the diagnostic accuracy of detection of myocardial infarction. Building on that background, practical tips that can be helpful in the recognition of myocardial infarction are reviewed.

Abstract 2334: Head-to-head Comparison of Whole-Heart Coronary MR and 40/64 slice Multidetector-CT Angiography for Detection of Coronary Artery Stenosis.

Purpose . Whole-heart magnetic resonance coronary angiography (WH-MRCA) has been recently proposed for non-invasive coronary imaging. Early studies have suggested that WH-MRCA might have similarly high diagnostic accuracy for detection of coronary disease as multidetector CT (MDCT). Yet, no direct comparison between both techniques has been performed. The aim of the present study was therefore to perform a head-to-head comparison of both techniques for detection of significant coronary stenoses using invasive cardiac catheterization as reference standard. Methods. Seventy-seven consecutive patients (56 M, 61±14 years) prospectively underwent free-breathing 3-dimensional WH-MRCA and 40/64-slice MDCT before cardiac catheterization. WH-MRCA and MDCT images were visually graded by 2 blinded observers and the diagnostic accuracy of both methods for detecting &gt;50% luminal diameter stenoses (DS) in segments and vessels &gt;1.5 mm size was compared using quantitative angiography (QCA) as reference method. Results. MDCT was successfully completed in all 77 patients in &lt; 5 minutes. By contrast, WH-MRCA failed in 9 patients (12%) because of poor navigator performance and lasted 20±4 minutes (p&lt;.01 vs MDCT). According to QCA, out of 992 segments &gt; 1.5 mm diameter, 49 presented &gt;50% DS. If all segments including non interpretable segments were considered, WH-MRCA had lower sensibility (35/49 or 71% vs. 45/49 or 92%, p&lt;0.001), lower specificity (644/943 or 68% vs. 863/943 or 92%, p&lt;0.001) and accuracy (679/992 or 68% vs. 908/992 or 92%, p&lt;0.001) for detection of coronary stenosis than MDCT. However if only interpretable segments were considered, the sensitivity (35/37 or 95% vs. 45/46 or 98%, p=0.58), specificity (644/689 or 93% vs. 863/917 or 94%, p=0.67) and diagnostic accuracy (679/726 or 94%, vs. 908/963 or 94%, p=0.58) of WH-MRCA and MDCT for detection of &gt;50% DS was similar. This was also the case on per-vessel basis. Conclusion. In the present study, MDCT had higher success rate than WH-MRCA. Therefore on an intention to diagnose basis, MDCT was superior to WH-MRCA. However, the diagnostic accuracy of WH-MRCA on per-segment and per-vessel basis was not statistically different from MDCT if only interpretable segments were considered.

Einsatz der Dual-source-Computertomographie in der prä- und postoperativen kardiochirurgischen Diagnostik

The aim of this study was to evaluate the clinical potential of dual-source computed tomography (DSCT) in pre- and postsurgical diagnostics in the field of cardiac surgery. A total of 20 patients underwent DSCT of the heart. This CT system with two rotating X-ray tubes (Somatom Definition, Siemens Medical Solutions, Forchheim, Germany) achieves a temporal resolution of 83 ms and a spatial resolution of 0.4 x 0.4 x 0.4 mm. The patient cohort consisted of two subgroups. In a group of ten patients with known coronary artery disease (CAD), scheduled for bypass surgery (i.e., high pretest likelihood for having significant CAD), the results of DSCT coronary angiography (CTA) and invasive quantitative catheter angiography (QCA) were compared to assess the diagnostic accuracy of DSCT in the detection of significant coronary artery stenoses (>50%). In a second group of ten patients with previous aortic valve replacement (homografts), the valve opening area of the transplanted aortic valve graft was measured by DSCT and compared with echocardiography as a standard of reference to exclude postsurgical restenosis of the valve. Of 150 coronary artery segments depicted by CT, 144 (96%) were classified as "assessable." A significant CAD was known in all patients, and altogether 43 significant stenoses were present according to the results of QCA. Blinded to these results, DSCTA reached a sensitivity and specificity of 95% (41/43) and 93% (103/111), yielding a positive and negative predictive value (PPV, NPV) of 79% (31/39) and 98% (103/105), respectively. In patients with aortic valve homografts, all DSCT datasets were considered as being of diagnostic image quality concerning valve depiction. The planimetric evaluation of the CT data as compared to results of echocardiography showed a significant correlation of the results (r=0.64, p=0.0467). A high-grade valve stenosis (opening area <1.0 cm(2)) could be correctly excluded by DSCT in all patients. Dual-source CT shows great diagnostic potential in patients before or after cardiac surgery. DSCT provides a high diagnostic accuracy for detection of coronary artery stenosis before bypass surgery. DSCT also proved to be accurate in the assessment of patients who received aortic valve replacement.

Coronary artery bypass grafts: assessment of graft patency and native coronary artery lesions using 16-slice MDCT

The objective of this study was to evaluate the accuracy of electrocardiography (ECG)-gated 16-slice multidetector-row computed tomography (MDCT) in detection of stenosis of bypass grafts and native coronary arteries in patients who have undergone coronary artery bypass grafting (CABG). ECG-gated contrast-enhanced MDCT using 12 x 0.75-mm collimation was performed in 20 patients with recurrent angina 4.75 years after undergoing CABG. A total of 50 grafts, 16 arterial and 34 venous, were examined. All graft and coronary segments were evaluated for stenosis in comparison with conventional coronary angiography (CCA). Among the 80 arterial graft segments, 62 could be assessed (77.5%). Sensitivity, specificity, and positive and negative predictive values for stenosis were 96.2%, 97.2%, 96.2%, and 97.2%, respectively. In a total of 180 venous graft segments, 167 could be assessed. Sensitivity, specificity, and positive and negative predictive values for stenosis were 98.5%, 93.9%, 91.8%, and 98.9%, respectively. MDCT could assess 179 of 260 native coronary artery segments (68.8%). Sensitivity, specificity, and positive and negative predictive values for stenosis were 92.1%, 76.9%, 87.5%, and 84.7%, respectively. Sixteen-slice MDCT provides excellent image quality and diagnostic accuracy in detection of graft and coronary artery lesions in patients with suspected graft dysfunction.

Contrast radiology, computed tomography and ultrasonography in detecting internal fistulas and intra-abdominal abscesses in Crohn’s disease: a prospective comparative study

Objectives Accurate assessment of intestinal complications of Crohn’s disease (CD) is extremely important, both in clinical practice and in trials. The accuracy of radiographic and ultrasonographic diagnosis of internal fistulae and abscesses complicating CD is still debated and requires further investigation. We compared ultrasonography (US) and contrast radiography in detecting intestinal fistulae and abscesses complicating CD. Methods A prospective study was carried out on 625 consecutive CD patients who underwent complete evaluation of the intestinal tract by means of colonoscopy and double contrast barium enema, small bowel enteroclysis, and abdominal ultrasound (US). Computed tomography (CT) was also carried out in cases of severe CD with clinical suspicion of septic complications. The accuracy of US, barium radiology, and CT in detecting internal fistulae and abscesses was assessed by comparing results with intraoperative findings in 128 consecutive patients who underwent operation immediately after diagnostic workup. Results Internal fistulae and intra-abdominal abscesses were identified intraoperatively in 56 (43.7%) and 26 (20.3%) patients, respectively. Diagnostic accuracy of US and x-ray studies in detecting internal fistulae was comparable (85.2% vs 84.8%), with sensitivity of 71.4% for US and 69.6% for x-ray studies, and specificity of 95.8% for both. Combination of radiographic techniques and US significantly improved diagnostic accuracy in detection of internal fistulae. In severe cases of CD with clinical suspicion of septic complications such as abdominal mass or fever, the accuracy of US, barium studies, and CT was 88.5%, 80.3%, and 77%, respectively ( p = ns). The presence of abscesses was correctly detected in 90.9% of cases by means of US and in 86.4% by CT ( p = ns), although accuracy was higher for CT (91.8%) than for US (86.9%) because of false positive results in US studies. Conclusion Despite the fact that barium radiology is widely considered the method of choice in detection of internal fistulae, accuracy is not entirely satisfactory. Comparable accuracy was found for US and CT. The combination of barium and US studies, or the sole use of US in more CD patients with more severe disease, can reliably detect most internal fistulae and abscesses.

Anomalous origin of the right coronary artery

We appreciate the comments from professor Probal K. Ghosh concerning amomalous origin of right coronary artery (ARCA), supporting our conclusion that myocardial revascularization is advisable in symptomatic patients with ARCA even though ischemia cannot be detected by exercise testing or myocardial scintigraphy [ 11. The technetium scintigraphy (99m Tc-sestamibi) used in our case report may be more accurate than a thallium scintigraphy in detecting myocardial perfusion abnormalities [2,3]. Limitations of both techniques particularly in detecting ischemia at the infero-basal portion of the myocardium have been demonstrated [4]. Due to a higher spatial resolution, a PET (dipyridamole) perfusion scanning may have improved the diagnostic accuracy for detection of myocardial perfusion defects. However, uncertainty of the dynamic characteristics of ARCA (compression or kinking of the artery, closure of a slit-like orifice, vasospasm) may be the critical factor that makes the decision of surgical correction to rely only on the patient’s symptoms and the angiographic findings.

Evaluation of an Enhanced Digital Film-Duplication System by Receiver Operating Characteristic Analysis

Over- or underexposure often results in poor quality radiographs. Using receiver operating characteristic analysis, the authors investigated the potential utility of a system that corrects densities in such images to improve the accuracy of lung nodule detection. Chest radiographs were digitized by a laser film digitizer. Simulated nodules were superimposed on 36 improperly exposed chest radiographs. All images, with and without nodules, were then processed by a nonlinear density-correction technique. Hard-copy images were produced by a laser film printer. Eight radiologists evaluated the corrected and uncorrected images for the presence or absence of lung nodules using a continuous (0-100) confidence-rating scale. The detectability of lung nodules improved significantly in the retrocardiac/retrodiaphragmatic regions of underexposed images and in the peripheral lung region of overexposed images. This system may increase diagnostic accuracy in detection of lung nodules in improperly exposed images.