Search

PURPOSE Dilatation of the thoracic aorta is a well-known finding in corrected Tetralogy of Fallot. Complications are rare but can be life-threatening. Standard 1-dimensional (1D) measurements have several limitations. We sought to establish contrast-enhanced magnetic resonance angiography cross-sectional areas of the aorta that could serve as reference values and to identify parameters that are associated with aortic dilatation. MATERIALS AND METHODS We enrolled 101 children and adolescents. The aortic areas were measured at the level of the aortic sinus (AS), the sinotubular junction (STJ), the ascending aorta (AA), the brachiocephalic trunk (TBC), and the descending aorta (DA). Sex-specific aortic dimensions were presented as percentile curves as well as regression equations. Furthermore volumetric and functional parameters as well as clinical data were analyzed to identify parameters that are associated with aortic dilatation. RESULTS Aortic areas (mm) for female subjects were 139+366×body surface area (BSA) for the AS, 134+255×BSA for the STJ, 113+239×BSA for the AA, 88+185×BSA proximal to the TBC, and 2.9+88×BSA for the DA. Aortic areas (mm) for male subjects were 162+403×BSA for the AS, 171+258×BSA for the STJ, 151+233×BSA for the AA, 73+206×BSA proximal to the TBC, and 21+80×BSA for the DA. The postoperative interval and age at examination were parameters associated with aortic size. CONCLUSIONS We provide aortic areas in children and adolescents after correction of Tetralogy of Fallot measured by contrast-enhanced magnetic resonance angiography. Our 2D data may better depict the geometry of enlarged aortae than standard 1D diameters and serve as reference values for evaluating aortic disease in these patients.

Background Intramyocardial haemorrhage (IMH) and microvascular obstruction (MVO) represent reperfusion injury after reperfused ST-elevation myocardial infarction (STEMI) with prognostic impact and “hypointense core” (HIC) appearance in T2-weighted images. We aimed to distinguish between IMH and MVO by using T2*-weighted cardiovascular magnetic resonance imaging (CMR) and analysed influencing factors for IMH development. Methods and results A total of 151 patients with acute STEMI underwent CMR after primary angioplasty. T2-STIR sequences were used to identify HIC, late gadolinium enhancement to visualise MVO and T2*-weighted sequences to detect IMH. IMH+/IMH− patients were compared considering infarct size, myocardial salvage, thrombolysis in myocardial infarction (TIMI) flow, reperfusion time, ventricular volumes, function and pre-interventional medication. Seventy-six patients (50 %) were IMH+, 82 (54 %) demonstrated HIC and 100 (66 %) MVO. IMH was detectable without HIC in 16 %, without MVO in 5 % and HIC without MVO in 6 %. Multivariable analyses revealed that IMH was associated with significant lower left ventricular ejection fraction and myocardial salvage index, larger left ventricular volume and infarct size. Patients with TIMI flow grade ≤1 before angioplasty demonstrated IMH significantly more often. Conclusions IMH is associated with impaired left ventricular function and higher infarct size. T2 and HIC imaging showed moderate agreement for IMH detection. T2* imaging might be the preferred CMR imaging method for comprehensive IMH assessment. Key Points • Intramyocardial haemorrhage is a common finding in patients with acute reperfused myocardial-infarction. • T2*imaging should be the preferred CMR method for assessment of intramyocardial haemorrhage. • Intramyocardial haemorrhage can be considered as an important influencing factor on patient’s outcome.

Objective Comparing the diagnostic value of multi-sequential cardiac magnetic resonance imaging (CMR) with endomyocardial biopsy (EMB) for sub-clinical cardiac allograft rejection. Methods One hundred and forty-six examinations in 73 patients (mean age 53 ± 12 years, 58 men) were performed using a 1.5 Tesla system and compared to EMB. Examinations included a STIR (short tau inversion recovery) sequence for calculation of edema ratio (ER), a T1-weighted spin-echo sequence for assessment of global relative enhancement (gRE), and inversion-recovery sequences to visualize late gadolinium enhancement (LGE). Histological grade ≥1B was considered relevant rejection. Results One hundred and twenty-seven (127/146 = 87 %) EMBs demonstrated no or mild signs of rejection (grades ≤1A) and 19/146 (13 %) a relevant rejection (grade ≥1B). Sensitivity, specificity, positive predictive, and negative predictive values were as follows: ER: 63 %, 78 %, 30 %, and 93 %; gRE: 63 %, 70 %, 24 %, and 93 %; LGE: 68 %, 36 %, 13 %, and 87 %; with the combination of ER and gRE with at least one out of two positive: 84 %, 57 %, 23 %, and 96 %. ROC analysis revealed an area under the curve of 0.724 for ER and 0.659 for gRE. Conclusion CMR parameters for myocarditis are useful to detect sub-clinical acute cellular rejection after heart transplantation. Comparable results to myocarditis can be achieved with a combination of parameters. Key Points • Magnetic resonance imaging is useful for the assessment of cardiac allograft rejection. • CMR has a high negative predictive value for exclusion of allograft rejection. • Diagnostic performance is not yet good enough to replace endomyocardial biopsy.

Der perkutane, kathetergestutzte Aortenklappenersatz („transcatheter aortic valve implantation“, TAVI) ist eine etablierte Alternative fur Patienten mit schwerer Aortenklappenstenose (AS), wenn sie wegen Komorbiditaten und damit verbundenem hohem perioperativem Risiko oder Kontraindikationen fur einen konventionellen, offen-chirurgischen Aortenklappenersatz nicht geeignet sind. Fur eine adaquate Indikationsstellung, Prothesenwahl und Prothesengrosenbestimmung und somit fur eine Verminderung periinterventioneller Komplikationen spielt die praprozedurale Bildgebung eine entscheidende Rolle. Neben der Dopplerechokardiographie, die v. a. fur die Graduierung der AS und die periinterventionelle Bildgebung genutzt wird, nimmt die Computertomographie eine hervorgehobene Stellung ein. Mit ihr kann nicht nur die komplexe dreidimensionale Geometrie des Aortenbulbus, sondern auch der Aorta und der peripheren Gefase als potenzielle Zugangswege zuverlassig beurteilt und vermessen werden.

To determine the time course of enhancement patterns in the aorta and endoleaks at dynamic computed tomographic (CT) angiography as well as their effect on the endoleak detection rate in patients who have undergone abdominal aortic endovascular aneurysm repair (EVAR).This retrospective study was approved by the local ethics committee and compliant with the Declaration of Helsinki. All patients gave written informed consent for the scientific analysis of their data. Seventy-one patients (mean age, 72 years ± 8 [standard deviation]) were retrospectively included after EVAR of the abdominal aorta. All patients underwent dynamic CT angiography with 10 unidirectional scan phases, followed by a venous phase. Endoleaks were detected visually in all scan phases; the magnitude of enhancement was assessed by using region-of-interest measurements in the aorta and the detectable endoleaks. Statistical analysis was performed with the χ(2) test, the paired t test, and analysis of variance with repeated measurements.The highest mean aortic enhancement was achieved 12 seconds after the bolus-tracking threshold, and the highest mean endoleak enhancement was achieved 22 seconds after the bolus-tracking threshold. In total, 44 endoleaks were detected. The detection rates differed significantly in between the dynamic CT angiography phases (minimum, seven endoleaks at 2 seconds after the bolus-tracking threshold; maximum, 44 endoleaks at 27 seconds after the bolus-tracking threshold; P = .001). The highest detection rate was achieved when the contrast between aortic and endoleak enhancement reached its maximum.Dynamic CT angiography revealed that the peak enhancement of endoleaks is significantly different than that of the aorta and that endoleaks may not be adequately evaluated with conventional biphasic CT protocols. The use of dynamic CT angiography is associated with a significantly increased detection rate of endoleaks compared with the detection rates at the time points of conventional biphasic CT.

To evaluate the inter-individual variance and the variability of the aortic root dimensions during the cardiac cycle by computed tomography (CT) in patients with severe aortic stenosis prior to transcatheter aortic valve implantation (TAVI). Fifty-six patients (m/w = 16/40, 81 ± 6.8 years), scheduled for a transapical aortic valve implantation with available preprocedural ECG-gated CT were retrospectively included. The evaluation included sizing of the aortic annulus and the aortic sinus, measurements of the coronary topography, aortic valve planimetry and scoring of calcification. The new defined aortic annulus sphericity ratio revealed a mostly elliptical shape with increasing diastolic deformation. The calculated effective diameter (ED), determined from the annulus’ lumen area, turned out to be the parameter least affected from cardiac cycle changes while systolic and diastolic annulus dimensions and shape (diameter and area) differed significantly (p

To assess differences in aortic and endoleak enhancement in patients after endovascular aneurysm repair (EVAR) with dynamic computed tomography (CT) angiography.Twenty-one consecutive patients (mean age, 74.5 y ± 6; range, 61-88 y) with endoleaks after EVAR of the abdominal aorta were examined on a second-generation dual-source CT unit with 10 unidirectional scan phases (temporal resolution, 5 s; 80 kV; 120 reference-mAs; z-axis field of view, 283 mm), followed by a venous scan phase. Enhancement was assessed in aorta and endoleaks for all phases by density measurements. The diagnostic reliability of endoleak detection was assessed on a five-point confidence scale.In total, 26 endoleaks (type I, n = 1; type II, n = 25) were detected. The highest detection rate was found in phase 5 (22 s after threshold; P.01 vs other dynamic phases). Mean peak aortic enhancement (560 HU ± 96) was present in an early arterial phase (phase 3, 12 s after threshold), whereas the mean peak endoleak enhancement (398 HU ± 174) for type II endoleaks was present later, in phase 4 (17 s after threshold). Despite perceived high diagnostic confidence in phases 1 and 2 (ie, typical arterial phase of biphasic CT protocol), only 23% and 62% of endoleaks were detected, respectively, whereas peak diagnostic confidence (phases 4 and 5) corresponded well with the maximum endoleak detection rate but decreased significantly in later phases (ie, 6-10).Preliminary dynamic CT angiography results in post-EVAR follow-up revealed notably different peaks of endoleak and aortic enhancement, which are not covered sufficiently by conventional biphasic CT protocols. Phase 5 demonstrated the highest type II endoleak detection rate, with high diagnostic confidence.

To evaluate changes of right ventricular (RV) parameters in follow-up examinations after corrected tetralogy of Fallot (TOF) by cardiac magnetic resonance (CMR). CMR was performed twice within 4 years in 45 patients using a 1.5 T scanner. RV-volumes and pulmonary-regurgitant-fractions (PRF) were calculated from standard cine-sequences and flow-sensitive gradient-echo images, respectively. Patients were divided into two groups depending on the post-operative (po) interval (group 1 ≤5 years po; group 2 >5 years po) and subgroups depending on type of surgery (transannular vs. non-transannular). Patient groups were compared among each other and differences between 1st and 2nd CMR were assessed. Furthermore, patients were compared with 25 healthy volunteers. Compared with controls RV-size was increased (group 1: p = 0.007; group 2: p

Coronary artery fistulas are rare acquired or congenital abnormalities leading to a shunt between a coronary artery and one of the cardiac cavities, a main artery, or a vein. This case report describes the combined use of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) for the precise anatomical and functional assessment of a right coronary artery (RCA) fistula shunting to the coronary sinus. The RCA itself showed a massively elongated deformation and a maximal aneurysmatic dilatation of 41 mm on MDCT and MRI. The absolute shunt volume calculated by MRI flow measurements at the RCA was 40 ml, which means 37% in relation to the measured LV stroke volume of 109 ml.

To compare the performance of semi-automatic versus manual segmentation for ECG-triggered cardiovascular computed tomography (CT) examinations prior to transcatheter aortic valve replacement (TAVR), with focus on the speed and precision of experienced versus inexperienced observers. The preoperative ECG-triggered CT data of 30 consecutive patients who were scheduled for TAVR were included. All datasets were separately evaluated by two radiologists with 1 and 5 years of experience (novice and expert, respectively) in cardiovascular CT using an evaluation software program with or without a semi-automatic TAVR workflow. The time expended for data loading and all segmentation steps required for the implantation planning were assessed. Inter-software as well as inter-observer reliability analysis was performed. The CT datasets were successfully evaluated, with mean duration between 520.4 ± 117.6 s and 693.2 ± 159.5 s. The three most time-consuming steps were the 3D volume rendering, the measurement of aorta diameter and the sizing of the aortic annulus. Using semi-automatic segmentation, a novice could evaluate CT data approximately 12.3 % faster than with manual segmentation, and an expert could evaluate CT data approximately 10.3 % faster [mean differences of 85.4 ± 83.8 s (p

Purpose: To compare the performance of server-based (CSS) versus stand-alone post-processing software (ES) for the evaluation of cardiovascular CT examinations (cvCT) and to determine the crucial steps. Materials and Methods: Data of 40 patients (20 patients for coronary artery evaluation and 20 patients prior to transcatheter aortic valve implantation [TAVI]) were evaluated by 5 radiologists with CSS and ES. Data acquisition was performed using a dual-source 128-row CT unit (SOMATOM Definition Flash, Siemens, Erlangen, Germany) and a 64-row CT unit (Brilliance 64, Philips, Hamburg, Germany). The following workflow was evaluated: Data loading, aorta and coronary segmentation, curved multiplanar reconstruction (cMPR) and 3 D volume rendering technique (3D-VRT), measuring of coronary artery stenosis and planimetry of the aortic annulus. The time requirement and subjective quality for the workflow were evaluated. Results: The coronary arteries as well as the TAVI data could be evaluated significantly faster with CSS (5.5 ± 2.9 min and 8.2 ± 4.0 min, respectively) than with ES (13.9 ± 5.2 min and 15.2 ± 10.9 min, respectively, p≤ 0.01). Segmentation of the aorta (CSS: 1.9 ± 2.0 min, ES: 3.7 ± 3.3 min), generating cMPR of coronaries (CSS: 0.5 ± 0.2 min, ES: 5.1 ± 2.6 min), aorta and iliac vessels (CSS: 0.5 ± 0.4 min and 0.4 ± 0.4 min, respectively, ES: 1.6 ± 0.7 min and 2.8 ± 3 min, respectively) could be performed significantly faster with CSS than with ES with higher quality of cMPR, measuring of coronary stenosis and 3D-VRT (p Conclusion: Evaluation of cvCT can be accomplished significantly faster and better with CSS than with ES. The segmentation remains the most time-consuming workflow step, so optimization of segmentation algorithms could improve performance even further. Key points: • With client-server-based (CSS) and stand-alone solutions (ES), cardiovascular CT datasets can be evaluated reliably. • Evaluation of cardiovascular CT can be performed faster and better with CSS than with ES. • In particular the generating of curved reconstructions is faster with CSS than with ES. • Segmentation of data is a crucial step for semiautomatic software (CSS and ES). Citation Format: • Lucke C, Foldyna B, Andres C et al. Post-Processing in Cardiovascular Computed Tomography: Performance of a Client Server Solution versus a Stand-Alone Solution. Fortschr Rontgenstr 2014; 186: 1111 – 1121

Das klinische Syndrom der rheumatoiden Vaskulitis (RV) hat sich in den letzten 40 Jahren als Begriff in der Rheumatologie etabliert, ohne das es bisher eine feststehende Begriffsdefiniton gibt. Bei der rheumatoiden Arthritis (RA), einer chronisch entzundlichen Erkrankung des Bindegewebes mit bevorzugtem Befall der Gelenkinnenhaut und daraus resultierender Knorpel- und Knochendestruktion werden haufig extraartikulare Erscheinungen beobachtet, deren bekannteste das Auftreten von Rheumaknoten darstellt (Rheumatismus nodosus). Auch bei der Riesenzellarteriitis (RZA) ergeben die Laborbefunde oft ausgepragte Entzundungskonstellationen, obwohl das morphologische Substrat dieser Entzundung noch nicht restlos geklart zu sein scheint. Das klinische Syndrom der Polymyalgia rheumatica (PMR) ist mit der RZA sehr haufig assoziiert, aber auch die RA im hoheren Lebensalter bereitet differentialdiagnostisch wegen ihrer zu Beginn haufig polymyalgiformen Symptomatik grose Probleme, zumal auch fluchtige Synovitiden vor allem an Knie- und Handgelenken bei der PMR beobachtet werden. Aus der Entzundung und Schadigung von Blutgefasen resultieren Lumeneinengung und damit Ischamie im vom betroffenen Gefas versorgten Gewebe, die bei der Arteriitis cranialis zur Erblindung fuhren kann. Aus Permeabilitatsstorungen der Endstrecken im Gefasbett entstehen Schadigungen der molekularen Austauschflachen in Organen wie Niere oder Lunge bis hin zum Organversagen.

A recent study reported that exposure of student embalmers in Cincinnati to high concentrations of formaldehyde (2 mg/m3) reduced the activity of the DNA repair protein O6-methylguanine DNA methyltransferase (MGMT). Reduction in a DNA repair enzyme may strongly increase the cancer risk not only with respect to the repair-enzyme causing agent but with respect to all carcinogens causing lesions subject to repair by the enzyme in question. Thus, we examined whether formaldehyde exposure of 57 medical students during their anatomy course at two different Universities in Germany influenced MGMT activity in mononuclear blood cells. Mean formaldehyde exposure of 41 students was 0.2 +/- 0.05 mg/m3 for 6 h per week. MGMT activity was 133.2 +/- 14.9 fmol MGMT/10(6) cells before the beginning of the formaldehyde exposure, 131.1 +/- 15.8 fmol MGMT/10(6) cells after 50 days (P = 0.56) and 128.2 +/- 19.0 fmol MGMT/10(6) cells after 111 days of exposure (P = 0.92). Similarly, no significant influence of formaldehyde exposure was observed, when smoking habits, alcohol consumption, allergic disease and sex of students were considered. In addition no significant difference was obtained in MGMT activity between 16 students with mean formaldehyde exposure of 0.8 +/- 0.6 mg/m3 and students without formaldehyde exposure (n = 51; P = 0.37). In conclusion, exposure of the medical students in western Europe to formaldehyde did not decrease MGMT activity in mononuclear blood cells.

Percutaneous transcatheter aortic valve implantation (TAVI) is an established alternative to open heart surgery in patients with severe aortic stenosis (AS) unsuitable for conventional aortic valve replacement due to comorbidities with a high perioperative risk or contraindications. Preprocedural imaging plays a major role for adequate determination of indications and prosthesis selection, prosthesis sizing and therefore for a reduction of periprocedural complications. Besides Doppler echocardiography which is mainly used for grading of the severity of aortic valve stenosis and peri-interventional imaging, cardiac computed tomography (CCT) is the imaging modality of choice. The CCT procedure not only allows for reliably assessment and measuring of the complex 3-dimensional geometry of the aortic root but also for the aorta and the peripheral vessels used as potential access paths.

Transcatheter aortic valve implantation (TAVI) is currently considered an acceptable alternative for the treatment of patients with severe aortic stenosis and a high perioperative risk or a contraindication for open surgery. The benefit of TAVI significantly outweighs the risk of the procedure in patients requiring treatment that are not suitable for open surgery, and leads to a lower mortality in the one-year follow-up. The absence of a direct view of the aortic root and valve remains a challenge for the transcatheter approach. While direct inspection of the aortic valve during open surgery allows an adequate prosthesis choice, it is crucial for TAVI to know the individual anatomical details prior to the procedure in order to assure adequate planning of the procedure and proper prosthesis choice and patient selection. Among the imaging modalities available for the evaluation of patients prior to TAVI, computed tomography (CT) plays a central role in patient selection. CT reliably visualizes the dimensions of the aortic root and allows a proper choice of the prosthesis size. The morphology of the access path and relevant comorbidities can be assessed. The present review summarizes the current state of knowledge regarding the value of CT in the evaluation of patients prior to TAVI. CT plays a central role in patient selection and planning prior to TAVI. CT reliably detects the dimensions of the aortic root including the size of the aortic annulus, the degree of valve calcification and the morphology of the access routes.CT plays a central role in patient selection and planning prior to TAVI. CT reliably detects the dimensions of the aortic root including the size of the aortic annulus, the degree of valve calcification and the morphology of the access routes. CT provides a more accurate measurement of the aortic annulus than 2D TEE and CT is the only imaging modality that allows a risk assessment for paravalvular leakages based on the calcification of the aortic valve.

In familial defective apolipoprotein B-100 (FDB) the presence of a mutant apolipoprotein (apo) B-100 (FDB3500Q/W) in LDL markedly reduces their affinity for the LDL receptor, leading to elevated LDL cholesterol levels. However, the hypercholesterolemia in most FDB patients is relatively mild when compared with, e.g., familial hypercholesterolemia (FH). In order to study mechanisms that may partly alleviate the clinical consequences of FDB, we investigated the in vivo kinetics of apoB-100-containing lipoproteins in five FDB heterozygotes (total cholesterol: 7.84 +/- 1.37 mmol/I; total apoB: 1.68 +/- 0.37 g/l; mean +/- SD) and six normolipidemic controls (4.61 +/- 0.62 mmol/l; 0.98 +/- 0.12 g/l) using a stable isotope approach. During and after a 10-12 h primed, constant infusion of either [13C6]phenylalanine or [2H3]leucine, tracer enrichment was determined in apoB-100 from ultracentrifugally isolated VLDL1 (Sf 60-400), VLDL2 (Sf 20-60), IDL (Sf 12-20), LDL1 (Sf 7-12), and LDL2 (Sf 0-7). The rates of apoB-100 production, catabolism, and transfer were estimated by model-based compartmental analysis. The overall fractional catabolic rate (FCR) of IDL apoB-100 in FDB was substantially increased (2.99 +/- 0.68 pools/day vs. 1.70 +/- 0.23 pools/day in controls, P < 0.01). The fractional rate of apoB-100 transfer from IDL to LDL in FDB was decreased (0.97 +/- 0.13 pools/day vs. 1.24 +/- 0.10 pools/day, P < 0.05). The FCR of LDL apoB-100 in FDB was decreased (0.18 +/- 0.07 pools/day vs. 0.56 +/- 0.05 pools/, P < 0.01). Finally, the input rate of LDL apoB-100 in FDB was markedly decreased (9.45 +/- 2.96 mg/kg day1 vs. 15.54 +/- 1.70 mg/kg day1, P < 0.05). Our data suggest that the relatively small increase of LDL concentrations in FDB is due to an increased clearance of LDL precursor particles via the LDL-receptor and apoE-receptors as well as a decreased conversion of IDL to LDL - two mechanisms that distinguish FDB from FH.

Zielsetzung: Vergleich der Abstande der Koronarostien von den basalen Insertionsstellen der Aortenklappentaschen (AT) zur Lange der AT mittels Computertomografie (CT) vor transapikaler Aortenklappenimplantation (TAAVI) zur Beurteilung einer potentiellen intraproceduralen Obstruktion der Koronarostien durch die native AT. Material und Methoden: Es wurden 56 Patienten (40/16m/w, Durchschnittsalter 81±6,8 Jahre) mit schwerer Aortenstenose, geplanter TAAVI und vorliegender praoperativer CT eingeschlossen. Die Entfernungen des rechten und linken Koronarostiums zu den basalen Insertionsstellen der jeweiligen AT wurden in systolischer und diastolischer Phase gemessen und mit der Lange der diastolischen AT verglichen. Eine mogliche Uberlappung eines Koronarostiums wurde mittels paarweiser Analyse ermittelt. Ergebnisse: Die paarweise Analyse ergab eine mogliche Uberlappung von Teilen des rechten Koronarostiums durch die rechtskoronare AT' Mittlere Uberlappung 1,7±2,2' mm, p

To evaluate for the first time the degree of compliance between conventional multislice computed tomography (MSCT) and three-dimensional rotational angiography (3D-RA) in measuring relevant dimensions of the aortic annulus, the aortic root and the thoracic aorta in patients undergoing TA-AVI. Twenty-seven patients (82 ± 11 years) with severe aortic stenosis received contrast enhanced ECG gated MSCT prior to TA-AVI and intra-procedural rotational angiography. The aortic annulus size, the distance to the coronary ostia and diameters of the aortic root and the thoracic aorta were measured with both methods by two observers blinded to each other. Linear regression and Bland–Altman analysis were performed to determine the degree of compliance between both methods. The limits of agreement were within two standard deviations for all measurements and with high correlation especially for the supra-annular dimensions. Sizing of the aortic annulus revealed lower interobserver variability for MSCT than for 3D-RA with a maximum deviation of 2.1 ± 2.5 and 1.7 ± 2.8 mm for diameter measurements and for the effective diameter, respectively. With current protocols intra-procedural 3D-RA provides good image quality especially for structures above the aortic annulus. Due to a lower interobserver variability in sizing the aortic annulus MSCT remains more suitable for aortic root assessment prior to TA-AVI.

Fragestellung: Die bestehenden Abweichungen zwischen den jahrlichen Expansionsraten von Aortensegmenten in der CT, die aus dem Gefassegmentvolumen, dem maximalen orthogonalen Durchmesser, der maximalen orthogonalen Querschnittsflache und der Gefassegmentausenoberflache berechnet wurden, sollen bestimmt werden. Material und Methoden: Es wurden 73 Patienten (66±8,0 Jahre) retrospektiv in die Studie eingeschlossen, die zur Beurteilung des Gefasdiameters zwei CT-Angiografien der thorakalen und/oder abdominellen Aorta im mittleren Verlaufsintervall von 1,8±0,8 Jahren erhielten. Die Aorta wurde in 9 Segmente unterteilt (sinotubularer Ubergang bis Iliakalbifurkation). 346 Segmente konnten hinsichtlich Gefassegmentvolumen, maximalen orthogonalen Durchmesser, maximaler orthogonaler Querschnittsflache und Gefassegmentausenoberflache ausgewertet, die jahrlichen Expansionsraten berechnet und jeweils mit der des Gefassegmentvolumens als Standard verglichen werden. Ergebnisse: Die mittleren Differenzen zwischen Ausgangs- und Folgeuntersuchung betrugen fur das Volumen 5,7%±13,1 (4,8cm3±12,2), fur den Durchmesser 2,1%±4,9 (0,7mm±1,6), fur die Querschnittsflache 4,6%±13,6 (0,5cm2±1,1) und fur Ausenoberflache 4,8%±7,9 (3,7cm2±6,1). Im Vergleich mit der prozentualen Expansionsrate des Volumens war die prozentuale Expansionsrate des Durchmessers 2,7-fach, die der Querschnittsflache und der Ausenoberflache 1,2-fach niedriger. Zwischen den prozentualen Expansionsraten bestanden signifikante (p

A short run-time in separation of lipoproteins by preparative ultracentrifugation is desirable for several reasons. Recently, a method was described that needs only 100 min for one run in a centrifugal field of 625,000 x g. It is assumed that lipoprotein separation depends on the rotor speed but this has not been systematically studied in centrifugal fields of this order. We performed such a study. Rotor speeds of 120, 90, 60 and 30 x 10(3) rev./min and run-times of 100 min, 3 h, 6.7 h and 27 h were selected in such a way that the product of centrifugal field and run-time remained constant. The first conditions correspond to the 'very fast ultracentrifugation' (VFU) procedure with a centrifugal field of 625,000 x g. The Optima tabletop ultracentrifuge, the rotor TLA-120.2 and thick wall open tubes for 1 ml were used. Thirteen different plasma samples covering a wide range of cholesterol and triglyceride concentrations were separated into VLDL, LDL and HDL in the course of two centrifugal runs at densities of 1.006 and 1.063. The constituents of the lipoproteins were calculated considering the mass of the tube contents after slicing. Recoveries of cholesterol, triglycerides and protein were 97%, 98% and 90%, respectively. The influence of the rotor speed on the apparent composition of the lipoproteins was small. With increasing rotor speed, VLDL-cholesterol became higher (by 14%, P < 0.001), VLDL-triglyceride became lower (by 6%, P < 0.012), LDL-cholesterol became lower (by 9%, P < 0.000). The effects on LDL-triglyceride and on HDL-cholesterol and HDL-triglyceride, did not reach statistical significance. Protein in VLDL and in LDL decreased and increased in 'HDL' (the subnatant of the LDL run). As checked by SDS-PAGE the protein effects were due to complete disappearance of albumin from VLDL and LDL while the apolipoproteins B-100, E and C-I to C-III remained unaffected. It is concluded that the main advantages of VFU are the short run-time and the disappearance of albumin from VLDL and LDL. The other compositional changes need to be further investigated.

To evaluate the influence of different heart rates and arrhythmias on scanner performance, image acquisition and applied radiation exposure in prospectively ECG triggered computed tomography (pCT).An ECG simulator (EKG Phantom 320, MüllerSebastiani Elektronik GmbH, Munich, Germany) was used to generate different heart rhythms and arrhythmias: sinus rhythm (SR) at 45, 60, 75, 90 and 120/min, supraventricular arrhythmias (e.g. sinus arrhythmia, atrial fibrillation) and ventricular arrhythmias (e.g. ventricular extrasystoles), pacemaker-ECGs, ST-changes and technical artifacts. The analysis of the image acquisition process was performed on a 64-row multidetector CT (Brilliance, Philips Medical Systems, Cleveland, USA). A prospectively triggered scan protocol as used for routine was applied (120 kV; 150 mAs; 0.4s rotation and exposure time per scan; image acquisition predominantly in end-diastole at 75% R-R-interval, in arrythmias with a mean heart rate above 80/min in systole at 45% of the R-R-interval; FOV 25 cm). The mean dose length product (DLP) and its percentage increase from baseline (SR at 60/min) were determined.Radiation exposure can increase significantly when the heart rhythm deviates from sinus rhythm. ECG-changes leading to a significant DLP increase (p0.05) were bifocal pacemaker (61%), pacemaker dysfunction (22%), SVES (20%), ventricular salvo (20%), and atrial fibrillation (14%). Significantly (p0.05) prolonged scan time (8 s) could be observed in bifocal pacemaker (12.8 s), pacemaker dysfunction (10.7 s), atrial fibrillation (10.3 s) and sinus arrhythmia (9.3 s).In prospectively ECG triggered CT, heart rate and rhythm can provoke different types of scanner performance, which can significantly alter radiation exposure and scan time. These results might have an important implication for indication, informed consent and contrast agent injection protocols.

To compare diagnostic performance and applicability of prospectively versus retrospectively gated 64-slice computed tomography coronary angiography (pro-CTCA vs. retro-CTCA) in a heterogeneous patient population compared to invasive coronary angiography.77 patients referred to an ECG-gated-CT of the chest were retrospectively included. Pro-CTCA was applied, whenever possible, alternatively retro-CTCA was performed. All coronary artery segments≥1.5 mm were analysed and image quality was assessed.In 39 patients retro-CTCA and in 38 patients pro-CTCA was applied, mean heart rate (HR) was 69.5±9.1 min(-1) and 62.8±5.9, respectively. For a stenosis≥50% segment-based (patient-based) analysis revealed a sensitivity, specificity, positive (PPV) and negative predictive value (NPV) of 97%, 98%, 71%, 100% (91%, 82%, 67%, 96%) using retro-CTCA and 94%, 97%, 75%, 99% (93%, 96%, 93%, 96%) using pro-CTCA. Sensitivity and NPV increased in the pro-CTCA group in patients with a HR65. Vessel-based analysis showed lower diagnostic performance for the right coronary artery (RCA) using pro-CTCA, which increased when HR65. Image quality did not differ significantly in both groups.Prospectively triggered CTCA in a heterogeneous patient group has a very high diagnostic accuracy and image quality, when used in HR≤65. A low HR is of special importance for the evaluation of the RCA.

Ziele: Ziel war es die, Ubereinstimmung und Variabilitat zwischen Computertomographie (CT) und Rotationsangiographie (Dyna-CT) in Bezug auf die Vermessung aller relevanten anatomische Mase fur einen transapikalen AKE zu bestimmen. Methode: Es wurden 27 Patienten (82+-11 Jahre, 21w/6m) mit hochgradiger Aortenklappenstenose und Indikation fur einen transapikalen Aortenklappenersatz (AKE) retrospektiv in unsere Studie eingeschlossen. Alle Patienten erhielten aus klinischer Indikation ein praoperatives kontrastmittelverstarktes EKG-synchronisiertes 64-Zeilen-CT und ein intraoperatives Dyna-CT unter rapid pacing zur Darstellung der Aortenwurzel und thorakalen Aorta. Nachbearbeitung und Bildanalyse wurden von 2 Radiologen verblindet durchgefuhrt. Die Ubereinstimmung beider Methoden wurde nach Bland-Altman ermittelt. Ergebnis: Alle fur einen transapikalen AKE relevanten Strukturen waren mit beiden Bildgebungsmethoden in ausreichendem Mase darstellbar. Die mittlere Differenz zwischen CT und Dyna-CT fur den Diameter des sinotubularen Ubergangs betrug 0.15±1.03mm, fur die Klappenebene 1.22±2.22mm und fur den Abstand der Koronarostien vom Leafletansatz 0.19±1.34mm links und 0.91±2.02mm rechts. Es ergab sich ein signifikanter Unterschied fur die Diametermessungen der Klappenebene zwischen CT und Dyna-CT (p=0.01). Diametermessungen des sinotubularen Ubergangs, des Koronarostienabstands zur Klappenebene, des Bulbus aortae und der Aorta ascendens ergaben keinen signifikanten Messunterschied zwischen CT und Dyna-CT (p=0.482–0.783), bei signifikanter Korrelation der Messwerte (r=0.881, r=0.878, r=0.744, r=0.886, r=0.911; p

ss Open Acce Meeting abstract 1035 Value of a 2D phase-sensitive inversion recovery (PSIR) sequence in comparison to a 3D inversion recovery gradient echo sequence (IR-GRE) for the detection of myocardial scar by MRI in different myocardial diseases Kathrin Schindler*1, Christian Lucke1, Alexander Kosser1, Janine Hoffmann1, Stefan Nitzsche1, Bernhard Schnackenburg2, Gerhard Schuler3, Holger Thiele3 and Matthias Gutberlet1

Background The efficacy of surgical ventricular reconstruction (SVR) for ischemic cardiomyopathy has never been truly quantified. Methods to assess ventricular flow have not been applied to these patients. The objective is to develop a volume-independent technique for assessing the effects of ischemic remodeling and SVR on left ventricular blood flow dynamics. Methods Cardiac magnetic resonance images from a healthy volunteer and from a patient before and after SVR were segmented and transformed to generate a grid model of the heart by generating numeric grids and running third-order approximations to achieve 850 grid images per cardiac cycle. These grids formed the skeletal structure of our patient-specific time-dependent ventricular geometry model, the Karlsruhe Heart Model, used for modeling fluid dynamics. We modeled flow, ejection fraction, and blood washout from the ventricle. The model was validated using a silicone ventricle and mock circulation. Results In the healthy heart and before SVR, ejection fractions were 0.61 and 0.15 and left ventricular volumes were 166 mL and 175 mL, respectively. Surgical ventricular reconstruction decreased left ventricular volume by one fourth. Postoperative ejection fraction was 0.18 in the patient. Post-SVR shape was more spherical than preoperatively and also more spherical than the healthy heart. Ventricular flow patterns in the patient were significantly altered by SVR. However, fluid washout from the ventricle was similar before and after SVR but worse than in the healthy heart. Conclusions Fluid dynamic modeling of the heart is possible based on cardiac magnetic resonance imaging data and enables volume-independent quantitative assessment of the surgical procedure. In the future, preoperative modeling for patients with remodeled ventricles may help to achieve optimized post-SVR flow characteristics and potentially outcomes.

Complications after acute myocardial infarction (AMI) concerning the wall structure may be a true aneurysm, intramyocardial dissection, rupture of the free left ventricular wall covered by pericardium or formation of pseudoaneurysm. Differentiation between these complications of AMI may be difficult as shown by the following case report but is of paramount importance because of the different management.

Background The aim of this study is to optimize the set-up and port placement in robotic surgery and enhance intraoperative orientation by video overlay of the angiographic coronary tree. Methods In three mongrel dogs and two sheep an electrocardiogram-triggered computed tomographic scan and coronary angiography were performed after placing cutaneous fiducials. The regions of interest (ie, heart, ribs, coronaries, internal thoracic artery) were segmented semiautomatically to create a virtual model of the animal. In this model the target regions of the total endoscopic bypass procedure along the internal thoracic artery and anastomotic area were defined. Algorithms for weighing visibility, dexterity, and collision avoidance were calculated after defining nonadmissible areas using a virtual model of the manipulator. Intraoperatively, registration of the animal and the telemanipulator was performed using encoder data of the telemanipulator by pointing to the fiducials. After pericardiotomy, the reconstructed coronary tree was projected into the videoscopic image using a semiautomatic alignment procedure. In dogs, the total endoscopic bypass procedure was completed on the beating heart. The first human case applying preoperative planning, intraoperative registration, and augmented reality was subsequently performed. Results The rigid transformation linked the patient's preoperative frame and the robot coordinate frame with a root mean square error of 9 to 15 mm. The predicted port placement derived from the model initially varied from the one chosen due to an incomplete formulation of the weighing procedure. After only a few iterations, the algorithm became robust and predicted a collision free triangle. Video overlay of the angiographic coronary tree into the videoscopic image was feasible. Conclusions Surgical planning and augmented reality are likely to enhance robotic surgery in the future. A more complete understanding of the surgical decision process is required to better formalize the planning algorithms.