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1.
Radiologe ; 51(1): 23-30, 2011 Jan.
Article in German | MEDLINE | ID: mdl-21113572

ABSTRACT

Aortic isthmus stenosis is the most common congenital aortic anomaly and is often a problem for therapy surveillance. In addition to possible comorbidities (e.g. bicuspid aortic valve) it is accompanied by various middle and long-term complications depending on the primary choice of the therapeutic procedure. Magnetic resonance imaging (MRI) plays an important role for the mostly young patients in the control of the aortic isthmus stenosis and therapy because it is non-invasive and there is no X-ray exposure. Radiologists should be well-informed on the principles of the therapeutic procedure in order to be competent in the interpretation of MRI findings. Due to the continuous development of MRI technology, techniques for functional evaluation (e.g. dynamic MRA, 4D PC flow measurement) are increasingly becoming available in addition to high-resolution MR angiography (MRA), which could predict the risk of possible complications, such as aneurysms. However, in this aspect further studies are necessary. Interventional therapy with stents and stent grafts is often employed for the therapy of possible complications following an operation (aneurysms, restenosis) but because of massive metal artefacts the use of MRI is often sometimes severely limited.


Subject(s)
Aortic Coarctation/diagnosis , Aortic Coarctation/surgery , Aortic Valve Stenosis/diagnosis , Aortic Valve Stenosis/surgery , Magnetic Resonance Angiography/methods , Surgery, Computer-Assisted/methods , Humans , Prognosis , Treatment Outcome
2.
Radiologe ; 50(6): 514-22, 2010 Jun.
Article in German | MEDLINE | ID: mdl-20445956

ABSTRACT

Cardiovascular diseases (CVD) are among the leading causes of death worldwide. Even in the 21(st) century CVD will still be the most frequent cause of morbidity and mortality. Precise evaluation of cardiac function is therefore mandatory for therapy planning and monitoring. In this article the contribution of MRI-based analysis of cardiac function will be addressed. Nowadays cine-MRI is considered as the standard of reference (SOR) in cardiac functional analysis. ECG-triggered steady-state free precession (SSFP) sequences are mainly used as they stand out due to short acquisition times and excellent contrast between the myocardium and the ventricular cavity. An indispensible requirement for cardiac functional analysis is an exact planning of the examination and based on that the coverage of the whole ventricle in short axial slices. By means of dedicated post-processing software, manual or semi-automatic segmentation of the endocardial and epicardial contours is necessary for functional analysis. In this way end-diastolic volume (EDV), end-systolic volume (ESV) and the ejection fraction (EF) are defined and regional wall motion abnormalities (RWMA) can be detected.


Subject(s)
Cardiac-Gated Imaging Techniques/methods , Heart Function Tests/methods , Image Enhancement/methods , Magnetic Resonance Imaging, Cine/methods , Ventricular Dysfunction, Left/diagnosis , Humans
3.
Radiologe ; 50(6): 523-31, 2010 Jun.
Article in German | MEDLINE | ID: mdl-20445957

ABSTRACT

BACKGROUND: The purpose of the study was to explore a "dark blood" technique and to compare it with a standard inversion recovery gradient echo (IR GRE) sequence in the visualization of myocardial infarction. PATIENTS AND METHODS: A total of 9 patients were examined with standard IR GRE and a "dark blood" sequence 15 mins after contrast medium application (0.2 mmol/kg body weight gadobenate dimeglumine). Contrast-to-noise ratios (CNR) were calculated for each sequence. RESULTS: The CNR(inf-lvc) was significantly higher in the "dark blood" technique compared to the IR GRE sequence, while the CNR(inf-myo) was significantly lower. CONCLUSIONS: Small subendocardial infarctions may be easier to detect with the "dark blood" technique. However, the standard IR GRE sequence is superior in the demarcation of infarctions in relation to the myocardium and cannot be replaced by the "dark blood" technique.


Subject(s)
Image Enhancement/methods , Magnetic Resonance Imaging/methods , Meglumine/analogs & derivatives , Myocardial Ischemia/diagnosis , Organometallic Compounds/administration & dosage , Contrast Media/administration & dosage , Female , Humans , Male , Meglumine/administration & dosage , Middle Aged , Reproducibility of Results , Sensitivity and Specificity
4.
Eur Radiol ; 19(2): 391-9, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18777025

ABSTRACT

To compare the image quality of dynamic lung MRI with variations of steady-state free-precession (SSFP) and gradient echo (GRE) cine techniques at 1.5 T and 3 T. Ventilated porcine lungs with simulated lesions inside a chest phantom and four healthy human subjects were assessed with SSFP (TR/TE=2.9/1.22 ms; 3 ima/s) and GRE sequences (TR/TE=2.34/0.96 ms; 8 ima/s) as baseline at 1.5 and 3 T. Modified SSFPs were performed with nine to ten images/s (parallel imaging factors 2 and 3). Image quality for representative structures and artifacts was ranked by three observers independently. At 1.5 T, standard SSFP achieved the best image quality with superior spatial resolution and signal, but equal temporal resolution to GRE. SSFP with improved temporal resolution was ranked second best. Further acceleration (PI factor 3) was of no benefit, but increased artifacts. At 3 T, GRE outranged SSFP imaging with high lesion signal intensity, while artifacts on SSFP images increased visibly. At 1.5 T, a modified SSFP with moderate parallel imaging (PI factor 2) was considered the best compromise of temporal and spatial resolution. At 3 T, GRE sequences remain the best choice for dynamic lung MRI.


Subject(s)
Lung/pathology , Magnetic Resonance Imaging/methods , Respiratory System/pathology , Adult , Animals , Artifacts , Contrast Media/pharmacology , Humans , Image Interpretation, Computer-Assisted , Observer Variation , Phantoms, Imaging , Radiography , Reproducibility of Results , Respiration , Respiratory System/diagnostic imaging , Swine , Time Factors
5.
Eur Radiol ; 18(3): 570-5, 2008 Mar.
Article in English | MEDLINE | ID: mdl-17909817

ABSTRACT

Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT), the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study was to evaluate the accuracy of DSCT in the assessment of left ventricular functional parameters with cardiac magnetic resonance imaging (MRI) as standard of reference. Fifteen patients (two female, 13 male; mean age 50.8 +/- 19.2 years) underwent CT and MRI examinations on a DSCT (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) and a 3.0-Tesla MR scanner (Magnetom Trio; Siemens Medical Solutions), respectively. Multiphase axial CT images were analysed with a semiautomatic region growing algorithms (Syngo Circulation; Siemens Medical Solutions) by two independent blinded observers. In MRI, dynamic cine loops of short axis slices were evaluated with semiautomatic contour detection software (ARGUS; Siemens Medical Solutions) independently by two readers. End-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined for both modalities, and correlation coefficient, systematic error, limits of agreement and inter-observer variability were assessed. In DSCT, EDV and ESV were 135.8 +/- 41.9 ml and 54.9 +/- 29.6 ml, respectively, compared with 132.1 +/- 40.8 ml EDV and 57.6 +/- 27.3 ml ESV in MRI. Thus, EDV was overestimated by 3.7 ml (limits of agreement -46.1/+53.6), while ESV was underestimated by 2.6 ml (-36.6/+31.4). Mean EF was 61.6 +/- 12.4% in DSCT and 57.9 +/- 9.0% in MRI, resulting in an overestimation of EF by 3.8% with limits of agreement at -14.7 and +22.2%. Rank correlation rho values were 0.81 for EDV (P = 0.0024), 0.79 for ESV (P = 0.0031) and 0.64 for EF (P = 0.0168). The kappa value of inter-observer variability were amounted to 0.85 for EDV, ESV and EF. DSCT offers the possibility to quantify left ventricular function from coronary CT angiography datasets with sufficient diagnostic accuracy, adding to the value of the modality in a comprehensive cardiac assessment. The observed differences in the measured values may be due to different post-processing methods and physiological reactions to contrast material injection without beta-blocker medication.


Subject(s)
Magnetic Resonance Imaging , Tomography, X-Ray Computed/methods , Ventricular Function, Left/physiology , Female , Heart Ventricles/anatomy & histology , Humans , Male , Middle Aged , Observer Variation , Organ Size , Prospective Studies , Stroke Volume/physiology
6.
Radiologe ; 47(11): 982-92, 2007 Nov.
Article in German | MEDLINE | ID: mdl-17938873

ABSTRACT

Aortic disease is associated with high morbidity and mortality and thus require an efficient and accurate diagnostic approach, especially in the acute setting. Multislice computed tomography (MSCT) with the option of high-resolution CT angiography (CTA) has emerged as the standard of reference in diagnosis and follow-up of patients with acquired aortic disease. Aortic dissection is the most common aortic emergency, but it remains undiscovered in up to 38% of cases. Sensitivity and specificity of MSCT in the assessment of aortic dissection are greater than 99%. The sensitivity of CT in the detection of inflammatory changes is 83%; its specificity is almost 100%; and its diagnostic accuracy is ca. 94%. This article outlines state-of-the-art principles in diagnostic CT imaging of acquired aortic disease.


Subject(s)
Aortic Diseases/diagnostic imaging , Aortography/methods , Tomography, Spiral Computed/methods , Adult , Algorithms , Aortic Dissection/diagnostic imaging , Aortic Aneurysm/diagnostic imaging , Aortic Aneurysm, Abdominal/diagnostic imaging , Aortic Aneurysm, Thoracic/diagnostic imaging , Aortic Diseases/surgery , Aortitis/diagnostic imaging , Blood Vessel Prosthesis Implantation , Contrast Media , Diagnosis, Differential , Electrocardiography , Follow-Up Studies , Hematoma/diagnostic imaging , Humans , Multicenter Studies as Topic , Postoperative Complications/diagnostic imaging , Prognosis , Sensitivity and Specificity , Stents , Time Factors
7.
AJR Am J Roentgenol ; 187(3): 695-701, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16928932

ABSTRACT

OBJECTIVE: The purpose of our study was to evaluate the dose reduction potential of combined online (x- and y-axes) and topogram-based (l) X-ray tube current modulation in CT colonography in a screening population. MATERIALS AND METHODS: Eighty asymptomatic individuals underwent CT colonography screening for colon polyps. A 16-MDCT scanner (Somatom Sensation 16) was used. Forty patients were examined at 120 kVp and 120 effective mAs (supine) and 40 effective mAs (prone) using online x- and y-axis tube current modulation. Another 40 patients were scanned using combined x-, y-, and z-axis tube current modulation. Individual patient radiation exposure was determined using the dose-length product. Image noise was determined by Hounsfield unit measurements in the colonic lumen at four anatomic levels. Image quality was rated on a 5-point confidence scale by two independent reviewers. The unpaired Student's t test (for radiation dose, image noise) and Wilcoxon's test (for image quality) were used to test for statistically significant differences between these values. RESULTS: Radiation dose was significantly lower in the patient group scanned with x-, y-, and z-axis tube current modulation than in the group scanned with x- and y-axis tube current modulation (supine: 4.24 vs 6.50 mSv, p < 0.0001; prone: 1.61 vs 2.38 mSv, p < 0.0001). Radiation dose was reduced by 35% (supine) and 33% (prone). No statistically significant difference was seen in overall image noise (supine: 15.9 vs 16.3 H, p = 0.13; prone: 23.5 vs 24.8 H, p = 0.44) or image quality (supine: 4.6 vs 4.5, p = 0.62; prone: 3.5 vs 3.6, p = 0.54). CONCLUSION: Combined x-, y-, and z-axis tube current modulation leads to a significant reduction of radiation exposure in CT colonography without loss of image quality.


Subject(s)
Colonic Polyps/diagnostic imaging , Colonography, Computed Tomographic/methods , Aged , Female , Humans , Male , Mass Screening , Middle Aged , Radiometry , Sensitivity and Specificity , Software
8.
Clin Res Cardiol ; 95(3): 174-8, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16598531

ABSTRACT

A 46-year old woman experienced an episode of arterial desaturation despite administration of 100% oxygen during anesthetization for an elective laparoscopy. Further evaluation revealed a giant pulmonary arteriovenous malformation (PAVM) with right-left shunt associated with previously undiagnosed hereditary hemorrhagic telangiectasia (HHT, Morbus Osler- Weber-Rendu). The PAVM was treated interventionally with an Amplatzer duct occluder. Transcatheter embolization of the PAVM was well tolerated with symptomatic and hemodynamic improvement. CT scan after six months demonstrated correct position of the duct occluder in the left pulmonary artery with nearly complete occlusion of the feeding vessel.PAVMs are rare direct communications between pulmonary arteries and veins, associated with HHT in the majority of cases and often presenting with dyspnea or major neurological complications due to paradoxic embolism. In this case report, we present a rational and stepwise diagnostic workup for this rare medical condition and show that transcatheter embolization is an appropriate treatment for larger malformations.


Subject(s)
Arteriovenous Malformations/complications , Arteriovenous Malformations/therapy , Balloon Occlusion/methods , Pulmonary Artery/abnormalities , Pulmonary Veins/abnormalities , Telangiectasia, Hereditary Hemorrhagic/complications , Telangiectasia, Hereditary Hemorrhagic/therapy , Arteriovenous Malformations/diagnosis , Female , Humans , Middle Aged , Telangiectasia, Hereditary Hemorrhagic/diagnosis , Treatment Outcome
9.
An Sist Sanit Navar ; 27(1): 63-72, 2004.
Article in Spanish | MEDLINE | ID: mdl-15146206

ABSTRACT

Since the introduction of last generation multislice MSCT systems and the development of simultaneous electrocardiographic-tracing image acquisition and retrospective reconstruction techniques into clinical routine, cardiac MSCT has been considered a very useful non-invasive technique for the study of cardiac pathology in the daily clinical practice. One of the main clinical applications of this diagnostic technique is the evaluation of the coronary arteries including detection and quantification of coronary calcium, multislice CT coronary angiography (anatomy, anatomical variants and anomalies of the origin and course), the angiographic evaluation of the patency of aortocoronary by-pass grafts and coronary stents, and plaque characterization. The new reconstruction and postprocessing programs allow to obtain, in addition, parameters of myocardial morphology and contraction and cardiac function. Other clinical applications include the characterization of cardiac masses and the evaluation of the pericardium.


Subject(s)
Coronary Angiography/methods , Heart/diagnostic imaging , Tomography, X-Ray Computed/methods , Clinical Trials as Topic , Coronary Disease/diagnostic imaging , Heart/anatomy & histology , Heart Neoplasms/diagnostic imaging , Humans
10.
Radiologe ; 44(2): 121-9, 2004 Feb.
Article in German | MEDLINE | ID: mdl-14991130

ABSTRACT

INTRODUCTION: The newest generation of 16-detector-row CT allows displaying the anatomy and assessment of coronary artery disease (CAD) when slow regular sinus rhythm is present. METHODS: For morphological assessment of cardiac structures by using Multi-detector row CT a dedicated scan protocol is obligatory. The indication for coronary CT angiography (CTA) is currently under investigation by several study groups. RESULTS: Because of the limited spatial and temporal resolution and coronary calcium artefacts, it is not possible with multislice CT angiography to assess coronary arteries in patients with established coronary artery disease. The anatomy of the coronary arteries can well be displayed with this technique. CONCLUSION: The high negative predictive value of coronary CTA may justify the investigation of symptomatic patients with intermediate pretest probability of CAD. Moreover coronary CTA is suitable for patients for displaying the origin and course of abnormal coronary arteries.


Subject(s)
Coronary Angiography , Coronary Artery Disease/diagnostic imaging , Coronary Vessel Anomalies/diagnostic imaging , Tomography, Spiral Computed , Artifacts , Calcinosis/diagnostic imaging , Contrast Media/administration & dosage , Humans , Sensitivity and Specificity , Technology Assessment, Biomedical
11.
Radiologe ; 44(2): 130-9, 2004 Feb.
Article in German | MEDLINE | ID: mdl-14991131

ABSTRACT

PURPOSE: The purpose of this study was the evaluation of multidetector-row computed tomography (MDCT) for the assessment of atherosclerotic coronary artery vessel wall changes. METHODS: In an ex vivo study, 17 human hearts were scanned with MDCT and results were compared to histopathology. Morphologic imaging criteria of MDCT for various plaque-types were developed. In a following in vivo study, 94 coronary MDCT angiograms (MDCTA) of patients with suspected coronary artery disease (CAD) were reviewed retrospectively, assessing the diagnostic value of the coronary MDCTA, and determining the number and correlations of the various plaques types as described in the ex vivo study. Additionally, volumetry of calcified and noncalcified plaque components was performed. RESULTS: In the ex vivo study, MDCT showed a high sensitivity for calcified and non-calcified plaques. Comparing the results with histopathology, characteristic image criteria could be determined for lipid-rich, fibrous and calcified plaque components. Reviewing the contrastenhanced in-vivo MDCT coronary angiographies, presence of noncalcified plaques was proven in 38% of the patients. In 5 patients with a calcium score of 0, presence of coronary atherosclerosis was proven in the contrastenhanced scan. CONCLUSIONS: MDCT is able to differentiate various plaque components in an ex vivo setting as well as invivo. Contrastenhanced MDCT of the coronary arteries allows for the detection of noncalcified plaques. In vivo volumetry of noncalcified plaques is feasible.


Subject(s)
Coronary Angiography , Coronary Artery Disease/diagnostic imaging , Tomography, Spiral Computed , Adult , Aged , Calcinosis/classification , Calcinosis/diagnostic imaging , Calcinosis/pathology , Contrast Media/administration & dosage , Coronary Artery Disease/classification , Coronary Artery Disease/pathology , Coronary Stenosis/classification , Coronary Stenosis/diagnostic imaging , Coronary Stenosis/pathology , Coronary Vessels/pathology , Female , Humans , In Vitro Techniques , Male , Middle Aged , Retrospective Studies , Sensitivity and Specificity , Technology Assessment, Biomedical
12.
Radiologe ; 44(2): 140-5, 2004 Feb.
Article in German | MEDLINE | ID: mdl-14991132

ABSTRACT

Nowadays coronary artery bypass grafting is increasingly performed using arterial grafts. Purpose of the study was the evaluation of a appropriate 16 detector-row CT angiography protocol in patients after predominantly arterial bypass grafting. Fourteen patients after bypass grafting were including into the study and CT angiography carried out in the early postoperative period using a 16 detector-row CT system. To reduce cardiac pulsation artifacts data acquisition was implemented using ECG-gating algorithms. Overall 43 grafts (37 arterial, 6 venous) were examined. In 13 patients surgery had been performed using composite grafts with T or TY configuration. The mean heart rate was 74.1 bpm and showed a negative correlation to the image quality (r=-0.65; p=0.01). However, all data sets were diagnostic. Contrast injection protocol allowed for a homogeneous opacification throughout the vessels of interest. All non-delineationable grafts (5) showed a close proximity to the heart (T or Y grafts). Cardiac surgery is increasingly focusing on arterial revascularisation in bypass grafting and therefore leading to new demands for non-invasive bypass graft imaging. 16 detector-row CT allows a reliable visualization of even composite arterial grafts. However, for detection of grafts in the proximity of the heart a reduction of the heart rate (<65-70) still seems to be necessary.


Subject(s)
Coronary Angiography , Coronary Artery Bypass , Coronary Restenosis/diagnostic imaging , Electrocardiography , Graft Occlusion, Vascular/diagnostic imaging , Imaging, Three-Dimensional , Postoperative Complications/diagnostic imaging , Radiographic Image Enhancement , Radiographic Image Interpretation, Computer-Assisted , Tomography, Spiral Computed , Aged , Algorithms , Arteries/transplantation , Artifacts , Contrast Media/administration & dosage , Female , Heart Rate/physiology , Humans , Iopamidol , Male , Middle Aged , Retrospective Studies , Sensitivity and Specificity , Veins/transplantation
13.
Radiologe ; 44(2): 152-7, 2004 Feb.
Article in German | MEDLINE | ID: mdl-14991134

ABSTRACT

Real-time multislice cine techniques lead to inaccurate results in ventricular volumes based on limited temporal resolution. The purpose of the study is to evaluate a real-time cine technique with parallel imaging algorithms in comparison to standard segmented techniques. Twelve patients underwent cardiac cine MRI using real-time multislice cine trueFISP. Temporal resolution was improved using parallel acquisition techniques (iPAT) and data acquisition was performed in a single breath-hold along the patients' short axis. Evaluation of EDV, ESV, EF and myocardial mass was performed and results compared to a standard segmented single-slice cine trueFISP. Combination of real-time cine trueFISP and iPAT provided a temporal resolution of 48 ms. Results of the multislice approach showed an excellent correlation to standard single-slice trueFISP for EDV (0.94, p <0.001), ESV (0.97, p <0.001) EF (0.99, p <0.001) and myocardial mass (0.93, p <0.001). No significant differences could be found. The use of parallel acquisition techniques (PAT) allow for a substantial improvement of temporal resolution in real-time cine MRI (<50 ms). Therefore these techniques enable an accurate and exact quantification of global ventricular function.


Subject(s)
Electrocardiography , Heart Function Tests , Image Enhancement , Image Processing, Computer-Assisted , Magnetic Resonance Imaging, Cine , Respiration , Ventricular Dysfunction, Left/diagnosis , Algorithms , Cardiac Volume/physiology , Hemodynamics/physiology , Humans , Myocardial Infarction/diagnosis , Myocardial Infarction/physiopathology , Pericarditis, Constrictive/diagnosis , Pericarditis, Constrictive/physiopathology , Sensitivity and Specificity , Ventricular Dysfunction, Left/physiopathology , Ventricular Function, Left/physiology
14.
Radiologe ; 42(9): 691-6, 2002 Sep.
Article in German | MEDLINE | ID: mdl-12244469

ABSTRACT

Since its introduction a few years ago, multidetector row CT (MDCT) has become a widely used diagnostic procedure and has been proven to be a valuable tool for various indications. A major issue using this new modality is the inherent risk of applying increased radiation exposure, when compared to single-slice CT or other imaging modalities.However, MDCT offers some valuable options to save radiation exposure, such as choosing optimized exposure parameters or its superior dose efficiency in comparison to single-slice CT. Multi-phasic examinations should be restricted to indications where definitely necessary. Modern scanners offer intelligent tools for further reduction of radiation dose, such as ECG- or bodyshape-based realtime dose modulation. A new field of applications is the low-dose CT for early detection of diseases. While acquiring thin slices with high spatial resolution, the dose can be reduced to similar values as in conventional radiography, especially when examining under high-contrast conditions. Using all these various options available, radiation exposure can sometimes even be lower than using a conventional single-slice helical CT.


Subject(s)
Artificial Intelligence , Radiometry/instrumentation , Tomography, Spiral Computed/instrumentation , Body Surface Area , Calibration , Contrast Media , Electrocardiography/instrumentation , Equipment Design , Equipment Safety , Humans , Image Processing, Computer-Assisted , Radiation Dosage
15.
Radiologe ; 42(9): 722-7, 2002 Sep.
Article in German | MEDLINE | ID: mdl-12244473

ABSTRACT

PURPOSE: Purpose of this study was the implementation of a new abdominal CT angiography protocol on a 16 detector-row CT scanner and the comparison to selective catheter angiography. METHODS: 76 patients with various vascular disorders underwent abdominal CT angiography on a recently developed 16 detector-row CT scanner using submillimeter slice collimation (16 x 0.75 mm). Results were compared with mesenteric and/or hepatic angiography in 17 patients performed during tumor embolization. Opacification was provided using individually tailored contrast application with a test bolus setting. To evaluate the contrast injection protocol density measurements within the vessel lumen were performed. RESULTS: Diagnostic image quality was achieved in all patients with angiographic comparison (n = 17). Within the hepatic and mesenteric vasculature up to 4th generation vessels could be identified. Compared to selective angiography CT angiography provided equivalent morphologic information up to the detectable vessel generation. With the applied contrast application regimen there were no significant differences in vessel enhancement along the abdominal aorta and iliac arteries. CONCLUSION: 16 detector-row CT enables whole abdominal angiographic studies with submillimeter resolution in a single breath-hold. The improved spatial resolution enables for high quality 3D visualization. Compared to invasive angiography, 16 detector-row CT reveals equivalent morphologic information.


Subject(s)
Abdomen/blood supply , Angiography/instrumentation , Image Processing, Computer-Assisted/instrumentation , Imaging, Three-Dimensional/instrumentation , Tomography, X-Ray Computed/instrumentation , Adult , Aged , Aged, 80 and over , Aortic Aneurysm/diagnostic imaging , Aortography/instrumentation , Arterial Occlusive Diseases/diagnostic imaging , Carcinoma, Hepatocellular/blood supply , Embolization, Therapeutic , Equipment Design , Female , Hepatic Artery/diagnostic imaging , Humans , Liver Neoplasms/blood supply , Male , Mesenteric Artery, Superior/diagnostic imaging , Middle Aged , Sensitivity and Specificity
16.
Radiologe ; 42(9): 733-8, 2002 Sep.
Article in German | MEDLINE | ID: mdl-12244475

ABSTRACT

PURPOSE: To evaluate image quality of coronary CT angiography with retrospectively ECG-gated 16 multi-slice spiral CT (MSCT), reconstructed with 0.75 mm slice thickness for optimal spatial resolution and with 1.3 mm slice thickness, to produce spatial resolution comparable to a 4-MSCT. MATERIALS AND METHODS: Ten patients underwent coronary CT angiography with a 16-MSCT (Siemens Sensation 16, Forchheim, Germany) with 0.75 mm detector collimation. Raw helical CT data were retrospectively reconstructed using two different settings. Setting A: B20f smooth kernel, axial MPR with 1.3 mm slice thickness and 0.7 mm increment. Setting B: B35f "HeartView" medium-smooth kernel, 0.75 mm slice thickness, 0.5 mm increment. In the axial slices two regions of interest (ROIs) were placed in the area of the aortic root (AR) and more caudal in the area of the left ventricle (LV). Image noise was determined by the standard deviation of the CT numbers.Two readers determined visibility of coronary arteries by standardized maximum intensity projections (MIP) post-processing in left, right anterior and left anterior oblique projection plane from setting A and B. Each projection was rated on a five point rating scale concerning plaque delineation. Points determined for each data set were summed up and used for comparison. RESULTS: No significant difference between the CT-numbers was found for setting A and B (A: 283.0 in AR/295.9 in LV and B: 282,9 in AR/297.2 in LV; p >0.2). However, the image noise was significantly different for setting A and B (A: 4.46 in AR/1.67 in LV and B: 8.16 in AR/7.38 in LV; p <0.01). Better delineation of the coronary arteries and atherosclerotic lesions could be achieved from MIP projections in setting B compared to setting A. CONCLUSION: Higher image noise is present in coronary 16-MSCT with thin-slice reconstruction compared to simulated 4-MSCT. However the MIP-reconstructions benefit most from the higher spatial resolution.


Subject(s)
Coronary Angiography/methods , Coronary Artery Disease/diagnostic imaging , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Tomography, Spiral Computed/methods , Electrocardiography/methods , Humans , Male , Middle Aged , Observer Variation , Retrospective Studies , Sensitivity and Specificity
17.
Radiologe ; 41(8): 633-9, 2001 Aug.
Article in German | MEDLINE | ID: mdl-11552377

ABSTRACT

The aim of the study was to analyze the use and indication of 3 imaging modalities (CT, DSA and MRI) for patients with suspicion of aortic aneurysm. During 18 months 383 patients with suspicion of aortic aneurysm were examined with CT (SCT/MSCT), 17 with digital subtraction angiography (DSA), and 15 with MRI. Diagnostic DSA was performed in 7 cases for planning endoluminal therapy, in 7 cases because of unclear findings in CT and in 4 cases because of dissection of the aorta. MRI was performed in 12 cases with previously performed CT and in 3 cases as the only imaging modality because of intolerance to iodinated contrast material. CT is a well established and in most cases sufficient method for the examination of patients with the suspicion of aortic aneurysm. CT is widely available, and provides good image quality and a high diagnostic accuracy. Additional examinations with DSA or MRI are necessary in less than 5% of the patients.


Subject(s)
Aortic Aneurysm/diagnosis , Aortic Dissection/diagnosis , Diagnostic Imaging , Aged , Aortic Dissection/therapy , Angiography, Digital Subtraction , Aortic Aneurysm/therapy , Aortography , Female , Humans , Image Enhancement , Magnetic Resonance Angiography , Male , Middle Aged , Sensitivity and Specificity , Tomography, X-Ray Computed
18.
Radiologe ; 41(8): 689-94, 2001 Aug.
Article in German | MEDLINE | ID: mdl-11552384

ABSTRACT

The aim of the study was to investigate the use of 2D and 3D reconstructions in examinations of the aorta with CT and MRI. Postprocessing of 5 data sets including 2D MPR reconstructions, 3D MIP reconstructions and 3D volume rendering reconstructions acquired with contrast enhanced CTA and 5 data sets acquired with contrast enhanced MRA were performed. The luminal diameter, the length of the aneurysm and the detection of dissection was assessed for the reconstructions and the source images. Aneurysms and dissections of the aorta were correctly identified on source images. 2D MPR reconstructions and source images allow for a clear and easy image analysis including cases with high signal intensity or density of surrounding tissue and complex anatomical structures. The diameter and length of pathological findings can be determined correctly wit 2D MPR reconstructions, even when the vessel orientation is not exactly inplane or throughplane in relation to the source images. MIP reconstructions are suitable for contrast enhanced MRA data sets with high C/N ratio and volume rendering reconstructions are suitable for contrast enhanced CTA data sets, where calcifications and bone have also high density. For 3D visualization of large volumes MIP reconstructions are the method of choice for MRA and volume rendering reconstructions for CTA, respectively. In addition, 2D MPR can be necessary to determine the diameter and length of pathological findings.


Subject(s)
Aortic Aneurysm, Abdominal/diagnosis , Aortic Aneurysm, Thoracic/diagnosis , Aortic Dissection/diagnosis , Aortography/methods , Image Processing, Computer-Assisted/methods , Magnetic Resonance Angiography/methods , Tomography, X-Ray Computed/methods , Adult , Aged , Algorithms , Female , Humans , Image Enhancement , Imaging, Three-Dimensional , Male , Middle Aged , Sensitivity and Specificity
19.
Int J Cardiol ; 76(1): 65-74, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11121598

ABSTRACT

Non-invasive imaging techniques for the detection of graft patency after multivessel coronary revascularisation may be useful for follow-up after surgery. Forty consecutive asymptomatic patients (38 men, age 59.9+/-1.3 years) who had undergone coronary bypass surgery with at least three grafts were examined by spiral computed tomography or magnetic resonance angiography 24.9+/-0.3 months after surgery, using conventional angiography as reference. In total, 133 grafts (37 internal mammary artery, 96 venous grafts) were analysed. Spiral computed tomography studies were performed with a subsecond scanner; for magnetic resonance angiography, a three-dimensional contrast-enhanced gradient echo technique with ultrashort echo time during breath holding was used. For spiral computed tomography, sensitivities were 76% (internal mammary artery) and 100% (venous graft). This was compared with 100% (internal mammary artery) and 92% (venous graft) assessed by magnetic resonance angiography (P=ns). The positive predictive values were 100% for internal mammary artery and venous graft (spiral computed tomography) and 100% (internal mammary artery), 92% for venous grafts studied by magnetic resonance angiography (P=ns). Both subsecond spiral computed tomography and contrast-enhanced magnetic resonance angiography are highly accurate and relatively non-invasive approaches of assessing coronary graft patency after multivessel revascularisation and have potential for follow-up assessment in the long term.


Subject(s)
Coronary Angiography , Coronary Artery Bypass , Magnetic Resonance Angiography , Tomography, X-Ray Computed , Vascular Patency , Contrast Media , Humans , Imaging, Three-Dimensional , Internal Mammary-Coronary Artery Anastomosis , Male , Middle Aged , Predictive Value of Tests , Prospective Studies , Saphenous Vein/transplantation , Sensitivity and Specificity
20.
Radiologe ; 40(9): 785-91, 2000 Sep.
Article in German | MEDLINE | ID: mdl-11056969

ABSTRACT

PURPOSE: To compare high resolution contrast-enhanced MR angiography (MRA) and digital subtraction angiography (DSA) in the assessment of supraaortic vessel stenosis. METHODS: 14 patients with suspicion of cerebrovascular disease or upper limb ischemia underwent selective DSA and high resolution contrast enhanced MRA employing a new Panoramic-Array coil. Stenosis assessment in comparison to DSA followed NASCET criteria. Additionally signal-/noise ratios (SNR) were evaluated to assess contrast enhancement. RESULTS: Diagnostic image quality was achieved in all patients. Sensitivity and specificity for assessing high-grade stenosis of the supraaortic vessels were 100% and 96% respectively. In the assessment of high-grade common or internal carotid artery stenosis sensitivity and specificity was 100%. CONCLUSION: High resolution contrast enhanced supraaortic MRA combined with new coil systems allow for a reliable assessment of stenoses along the whole vessel course including the aortic arch. Previous stent procedures limit its use in postinterventional follow-up.


Subject(s)
Aorta, Thoracic/pathology , Carotid Arteries/pathology , Magnetic Resonance Angiography , Adult , Aged , Angiography, Digital Subtraction/instrumentation , Angiography, Digital Subtraction/methods , Angiography, Digital Subtraction/statistics & numerical data , Aorta, Thoracic/diagnostic imaging , Arm/blood supply , Carotid Arteries/diagnostic imaging , Carotid Stenosis/diagnosis , Cerebrovascular Disorders/diagnosis , Contrast Media , Gadolinium DTPA , Humans , Iohexol/analogs & derivatives , Ischemia/diagnosis , Magnetic Resonance Angiography/instrumentation , Magnetic Resonance Angiography/methods , Magnetic Resonance Angiography/statistics & numerical data , Middle Aged , Sensitivity and Specificity
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