[MRI in cardiac sarcoidosis and amyloidosis]. / MRT bei kardialer Sarkoidose und Amyloidose.

CLINICAL/METHODICAL ISSUE: Sarcoidosis and amyloidosis are both multisystem disorders, which may involve the heart; however, isolated cardiac disease is rare. Diagnosis of cardiac sarcoidosis and amyloidosis is crucial because the patient prognosis is dependent on cardiac involvement and early treatment. STANDARD RADIOLOGICAL METHODS: Echocardiography is the first line imaging modality in the diagnostic work-up of both diseases, possibly giving hints towards the correct diagnosis. Besides myocardial biopsy and radionuclide studies cardiac magnetic resonance imaging (MRI) is routinely performed in patients suspect of having infiltrative cardiomyopathy. METHODICAL INNOVATIONS: The T1 mapping procedure is currently being evaluated as a new technique for detection and quantification of global myocardial enhancement, as seen in cardiac amyloidosis. PERFORMANCE: Sensitivities and specificities for detection of cardiac sarcoidosis and amyloidosis can be significantly improved by MRI, especially with late gadolinium enhancement (LGE) imaging. In cardiac sarcoidosis the use of LGE is outcome-related while in amyloidosis analysis of T1-mapping may be of prognostic value. PRACTICAL RECOMMENDATIONS: If cardiac involvement in sarcoidosis or amyloidosis is suspected cardiac MRI including LGE should be performed for establishing the diagnosis.

[MRI for therapy control in patients with aortic isthmus stenosis]. / MRT zur Therapiekontrolle bei Patienten mit Aortenisthmusstenose.

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.

Non-invasive contrast enhanced ultrasound for quantitative assessment of tumor microcirculation. Contrast mixed mode examination vs. only contrast enhanced ultrasound examination.

PURPOSE: To evaluate the different ultrasound techniques for quantification of contrast enhanced ultrasound (CEUS) in an experimental rat prostate carcinoma model. METHOD AND MATERIALS: Prostate carcinoma (MLLB-2) cells were subcutaneously injected into the right flank of male rat (Charles River, Sulzfeld, Germany, 180 to 220 g body weight). Following 18 days of subcutaneous tumor growth 9 rats underwent CEUS examination. Real time CEUS was performed after a bolus injection of SonoVue (0.2 ml, Bracco, Italy) via the lateral tail vein using a high end ultrasound system (Siemens Sequoia 512®/Acuson, Mountain View) with an 15 Mhz probe. Two different CEUS techniques, pure contrast (pc) and contrast with background (cbg) examination, were analyzed (CPS-software). Exported signal intensity (SI)-time curves and the normalized area under the curve (AUC) for the active tumor tissue, whole tumor and necrosis were compared. RESULTS: The mean normalized AUC for the active tumor tissue and the whole tumor was 0.84 and 0.5 in the pure contrast examination group and 0.49 and 0.3 for the contrast examination with background signal. Therefore the signal intensity of the pc group was in every examination significant higher than of the cbg group (p < 0.02). The advantage of using the additional background information is to detect the anatomic landmarks in the solid tumor model in comparison to the pure contrast enhanced ultrasound examination. CONCLUSION: The complete extension of the tumor is much easier to detect with the cbg technique due to orientation of the anatomic landmarks. As the signal intensity of the pc group is always significant higher we recommend this technique for quantification of contrast enhanced ultrasound, especially for the follow up of tumor microcirculation.

[Cardiac functional analysis with MRI]. / Kardiale Funktionsanalyse mittels MRT.

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.

[Late gadolinium enhancement in the diagnostics of ischemic heart disease: technical principles, contrast optimization and clinical application]. / Late-Gadolinium-Enhancement in der Diagnostik der koronaren Herzerkrankung : Technische Grundlagen, Kontrastoptimierung und klinische Anwendung.

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.

MRI of respiratory dynamics with 2D steady-state free-precession and 2D gradient echo sequences at 1.5 and 3 Tesla: an observer preference study.

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.

Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings.

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.

[CT angiography of the aorta]. / CT Angiographie der Aorta.

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.

Arterial T-graft in coronary surgery: comparison of selective coronary angiography and multi-slice computed tomography.

BACKGROUND: The main aim of our study was to compare the results and value of angiography and multi-slice computed tomography (MSCT) after coronary artery bypass grafting using complex arterial conduit combinations. METHODS: Twenty-six patients underwent coronary surgery. In all patients, we utilized a T-graft (free arterial graft centrally implanted into the left internal thoracic artery IN SITU). Postoperative coronary angiography and MSCT were carried out prior to discharge. The results were interpreted separately by two different investigators. RESULTS: One hundred and thirteen distal anastomoses using 59 grafts for T-graft combinations were performed in 26 patients. A mean of 3.5 peripheral anastomoses was established per patient. Angiography showed a bypass graft patency rate of 94.6 % (56/59). In angiography, the patency rate of anastomoses was 96.5 % (109/113). All occlusions were identified in sequential anastomoses. The bypass patency rate measured by MSCT was 100 % and the patency rate of anastomoses 100 %. Based on these results, MSCT showed a sensitivity of 98.9 %. The specificity was 50.8 %, the positive predictive value was 94.6 % and the negative predictive value had a level of 99.9 %. CONCLUSION: MSCT is a simple, less invasive and useful method of monitoring results after coronary surgery including anastomosis and graft patency after complex arterial grafts. Its value may be restricted for sequential anastomoses and angiography should be preferentially used in these cases.

Dose reduction and image quality in MDCT colonography using tube current modulation.

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.

Interventional embolization of a giant pulmonary arteriovenous malformation with right-left-shunt associated with hereditary hemorrhagic telangiectasia.

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.

[On the way to isotopic spatial resolution: technical principles and applications of 16-slice CT]. / Auf dem Weg zur isotropen räumlichen Auflösung: Technische Grundlagen und Anwendungen der 16-Schicht-CT.

The broad introduction of multi-slice CT by all major vendors in 1998 was a milestone with regard to extended volume coverage, improved axial resolution and better utilization of the tube output. New clinical applications such as CT-examinations of the heart and the coronary arteries became possible. Despite all promising advances, some limitations remain for 4-slice CT systems. They come close to isotropic resolution, but do not fully reach it in routine clinical applications. Cardiac CT-examinations require careful patient selection. The new generation of multi-slice CT-systems offer simultaneous acquisition of up to 16 sub-millimeter slices and improved temporal resolution for cardiac examinations by means of reduced gantry rotation time (0.4 s). In this overview article we present the basic technical principles and potential applications of 16-slice technology for the example of a 16-slice CT-system (SOMATOM Sensation 16, Siemens AG, Forchheim). We discuss detector design and dose efficiency as well as spiral scan- and reconstruction techniques. At comparable slice thickness, 16-slice CT-systems have a better dose efficiency than 4-slice CT-systems. The cone-beam geometry of the measurement rays requires new reconstruction approaches, an example is the adaptive multiple plane reconstruction, AMPR. First clinical experience indicates that sub-millimeter slice width in combination with reduced gantry rotation-time improves the clinical stability of cardiac examinations and expands the spectrum of patients accessible to cardiac CT. 16-slice CT-systems have the potential to cover even large scan ranges with sub-millimeter slices at considerably reduced examination times, thus approaching the goal of routine isotropic imaging.

Aorto-iliac multidetector-row CT angiography with low kV settings: improved vessel enhancement and simultaneous reduction of radiation dose.

The aim of the study was to implement an abdominal CT angiography protocol using 100 kVp and to compare SNR and CNR, as well as subjective image quality, to a standard CT angiography protocol using 120 kVp on a 16 detector-row CT scanner. Forty-eight patients were referred for routine abdominal CT angiography on a 16 detector-row CT scanner. Patients were scanned using either 120 or 100 kVp at constant mAs settings. Vessel opacification was provided by automated contrast injection using similar injection protocols. Density measurements were performed along the aorto-iliac axis with SNR and CNR calculation. In addition, the estimated effective patient radiation dose was calculated. Results of both protocols were compared. The 100-kVp protocol (432+/-80 HU) showed a significantly higher vessel density than the 120-kVp (333+/-90 HU; P<0.001) protocol, corresponding to an average increase in signal intensity of 30.7%. SNR (36.0 vs 37.0) and CNR (31.1 vs 31.7) for the 100-kV protocol were not significantly lower that those for the standard protocol (P=0.79 and P=0.87), whilst the average estimated dose was significantly lower using the 100-kVp protocol (6.7+/-0.4 vs 10.1+/-1.2 mSv; P<0.0001). Tube kVp reduction from 120 to 100 kVp allows for significant reduction of patient dose in abdominal CT angiography, without significant change in SNR,CNR and image quality.

[Cardiovascular whole body MRI with parallel imaging]. / Kardiovaskuläre Ganzkörper-MRT mit paralleler Bildgebung.

PURPOSE: To create a whole-body cardiovascular MRI protocol with parallel imaging (iPAT). MATERIAL AND METHODS: Twenty two persons participated in the whole body scan. Due to iPAT high resolution imaging of the heart could be performed. 3D contrast enhanced MR angiography (3D-CE-MRA) took only 62 s to cover the whole body at a spatial resolution of less than 1.4x1.0x1.5mm(3). Scan time for HASTE lung imaging could be reduced by the factor of 2 while maintaining the signal to noise ratio (SNR). Image quality was rated by 2 radiologists blinded to each other. RESULTS: Mean scan time was 104 min on the standard system and less than 80 min on the new system. 75% of all MRA segments were rated good in terms of vessel conspicuity, more than 80% had no venous overlay. One case of distal occlusion of the anterior tibial artery and two cases of myocardial infarction were detected. CONCLUSION: Parallel imaging offers the possibility of fast whole body imaging. A combination of morphologic and functional imaging can be performed within less than 80 min.

[Multislice CT of the heart: clinical applications]. / TC multicorte (TCMC) cardiaca: aplicaciones clínicas.

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.

[Indications for multislice CT angiography of coronary arteries]. / Indikationen für die Mehrschicht-CT-Angiographie der Koronararterien.

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.

[Evaluating multislice computed tomography for imaging coronary atherosclerosis]. / Evaluierung der Mehrzeilendetektorcomputertomographie zur Darstellung der koronaren Atherosklerose.

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.

[ECG-gated bypass CT angiography--application in imaging arterial bypasses]. / EKG-gesteuerte Bypass-CT-Angiographie--Einsatz in der Darstellung arterieller Bypässe.

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.

[Determining global heart function with real time TrueFISP in one respiratory cycle]. / Erfassung der globalen Herzfunktion mit Real-time-trueFISP in einer Atemphase.

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.

Moving-table MR angiography of the peripheral runoff vessels: comparison of body coil and dedicated phased array coil systems.

OBJECTIVE: The aim of our study was to compare the signal-to-noise ratio and the diagnostic accuracy of moving-table MR angiography of the peripheral arteries with body coil and dedicated phased array coil systems. SUBJECTS AND METHODS: Forty patients were examined with digital subtraction angiography and moving-table MR angiography with a 1.5-T MR imaging system either with a body coil (n = 20) or with a dedicated phased array coil (n = 20). The timing of contrast material was performed with real-time MR fluoroscopy. RESULTS: For the iliac artery, upper leg, and lower leg, the mean values for signal-to-noise ratios were 56, 51, and 17, respectively, for the body coil, and 54, 74, and 64, respectively, for the dedicated phased array coil. For the body coil, sensitivity and specificity in identifying stenosis greater than 50% and occlusions were 100% and 96%, respectively, for the iliac arteries, and 100% and 96%, respectively, for the upper leg. For the dedicated phased array coil, sensitivity and specificity for stenosis greater than 50% and occlusions were 100% and 96%, respectively, for the iliac arteries, and 100% and 98%, respectively, for the upper leg. Sensitivity and specificity were inferior for the body coil (88% and 85%) compared with the dedicated phased array coil (100% and 96%) in the lower leg. A significant difference of the mean values of contrast-to-noise ratio was found before and after subtraction for the dedicated phased array coil and body-coil techniques (Student's t test, p < 0.01). CONCLUSION: In comparison with the body coil, the dedicated peripheral phased array surface coil system improves signal-to-noise ratio for the upper and lower leg and diagnostic accuracy in the lower leg.