Quantification of periaortic adipose tissue in contrast-enhanced CT angiography: technical feasibility and methodological considerations

To examine the feasibility of the quantifcation of abdominal periaortic fat tissue (PaFT) (tissue within − 45 to − 195 HU) in enhanced CT-angiographies compared to unenhanced CT-scans and identify methodological issues afecting its clinical implementation. Using OsirixMD, PaFT volume and mean HU value were retrospectively measured within a 5 mm periaortic ring in paired unenhanced and enhanced abdominal aortic CT-scans. The correlation between PaFT values was examined in a derivation cohort (n=101) and linear regression analysis produced correction factors to convert values from enhanced into values from unenhanced CTs. The conversion factors were then applied to enhanced CTs in a diferent validation cohort (n=47) and agreement of corrected enhanced values with values from unenhanced scans was evaluated. Correlation between PaFT Volume und Mean HU from enhanced and unenhanced scans was very high (r >0.99 and r=0.95, respectively, p<0.0001 for both). The correction factors for PaFT Volume and Mean HU were 1.1057 and 1.0011. Potential confounding factors (CT-kilovoltage, slice thickness, mean intraluminal contrast density, aortic wall calcifcation, longitudinal variation of intraluminal contrast density, aortic diameter) showed no signifcant efect in a multivariate regression analysis (p>0.05). Bland-Altman analysis of corrected enhanced and unenhanced values showed excellent agreement and Passing–Bablok regression confrmed minimal/no residual bias. PaFT can be quantifed in enhanced CT-angiographies very reliably. PaFT Volume scores are very consistently slightly underestimated in enhanced scans by about 10%, while the PaFT Mean HU value remains practically constant and ofers distinct methodological advantages. However, a number of methodological issues remain to be addressed

The effect of sacubitril/valsartan compared to olmesartan on cardiovascular remodelling in subjects with essential hypertension: the results of a randomized, double-blind, active-controlled study

Aims: Progressive aortic stiffening eventually leads to left ventricular (LV) hypertrophy and heart failure if left untreated. Anti-hypertensive agents have been shown to reverse this to some extent. The effects of sacubitril/valsartan (LCZ696), a dual-action angiotensin receptor blocker (ARB), and neprilysin inhibitor, on arterial stiffness and LV remodelling have not been investigated. Methods and results: This was a randomized, multi-centre, double-blind, double-dummy, active-controlled, parallel group, study to compare the effects on cardiovascular remodelling of sacubitril/valsartan with those of olmesartan in patients with hypertension and elevated pulse pressure. Magnetic resonance imaging scans were used to assess LV mass and local aortic distensibility, at baseline and at 12 and 52 weeks after initiation of treatment. Central pulse and systolic pressure were determined using a SphymoCor® XCEL device at each time point. A total of 114 patients were included, with 57 in each treatment group. The mean age was 59.8 years, and 67.5% were male. Demographic characteristics did not vary between the two sets of patients. Left ventricular mass index decreased to a greater extent in the sacubitril/valsartan group compared to the olmesartan group from baseline to 12 weeks (−6.36 vs. −2.32 g/m2; P = 0.039) and from baseline to 52 weeks (−6.83 vs. −3.55 g/m2; P = 0.029). These differences remained significant after adjustment for systolic blood pressure (SBP) at follow-up (P = 0.036 and 0.019 at 12 and 52 weeks, respectively) and similar signals (though formally non-significant) were observed after adjusting for changes in SBP (P = 0.0612 and P = 0.0529, respectively). There were no significant differences in local distensibility changes from baseline to 12 or 52 weeks between the two groups; however, there was a larger reduction in central pulse pressure for the sacubitril/valsartan group compared to the olmesartan group (P = 0.010). Conclusion: Since LV mass change correlates with cardiovascular prognosis, the greater reductions in LV mass indicate valuable advantages of sacubitril/valsartan compared to olmesartan. The finding that LV mass index decrease might be to some extent independent of SBP suggests that the effect of the dual-acting agent may go beyond those due to its BP-lowering ability

Cardiovascular MRI at 1.5 and 3.0 Tesla with Cine-SSFP- and "Black-Blood"-FSE- sequences with and without the implementation of parallel imaging techniques

Die kardiale MRT erfordert eine hohe räumliche und zeitliche Auflösung bei möglichst kurzer Messzeit. Aufgrund physiologischer Limitationen seitens des Patienten ist die Nutzung immer schnellerer und stärkerer Gradientensysteme limitiert. Die Hochfeld-MRT bei 3.0 T und der Einsatz paralleler Bildgebungstechniken (pMRT) besitzen das Potenzial, die Anwendbarkeit und Effektivität der kardialen MRT weiter zu steigern, bedingt durch ein höheres Grundsignal sowie eine deutliche Verkürzung der Untersuchungszeit bei gleichzeitig möglicher höherer räumlicher und/oder zeitlicher Auflösung. Nachteilig ist vor allem eine erhöhte Energiedeposition im Gewebe und Artefaktanfälligkeit bei 3.0 T sowie die Verringerung der Signalstärke bei der pMRT. Der komplementäre Einsatz von 3.0 T und der pMRT ermöglicht es theoretisch, diese Nachteile zu überwinden. Bei 20 Probanden wurden Cine-SSFP- und „Black-Blood“-FSE-Sequenzen akquiriert mit der Fragestellung der generellen Durchführbarkeit der kardialen MRT bei 3.0 T, der Anwendbarkeit der pMRT bei 1.5 T und 3.0 T und der bestehenden Unterschiede zwischen beiden Feldstärken und Akquisitionsmodi („konventionell“/parallel) hinsichtlich quantitativer und qualitativer Ergebnisse. Die vorliegende Studie zeigt die generelle Anwendbarkeit von 3.0 T in der kardialen MRT ohne und mit Einsatz der pMRT auf. Bei 3.0 T fand sich sowohl bei Cine-SSFP- als auch den FSE- Sequenzen ein SNR- und CNR-Zuwachs in Abhängigkeit von der verwendeten Sequenzart, der Wichtung, der Scanebene und des jeweiligen Herzsegments. Bei beiden Feldstärken war die Bildqualität konventionell akquirierter Bilder im Mittel gut bis sehr gut, bei tendenziell schlechterer Bildqualität bei 3.0 T, bedingt durch das vermehrte Auftreten von Artefakten. Es zeigte sich eine Abhängigkeit der Bildqualität von der Wichtung und dem verwendeten Sequenztyp. Der Einsatz der pMRT führte bei beiden Feldstärken zu einer signifikanten Messzeitverringerung. Bei 1.5 T wiesen die konventionell und mit pMRT akquirierten Bilder eine gute bis sehr gute Bildqualität auf ohne signifikanten Unterschied. Aufgrund vermehrter Artefakte bei 3.0 T mit pMRT war die Bildqualität schlechter als bei 3.0 T konventionell, jedoch ausreichend für eine diagnostische Beurteilung. Der Vergleich zwischen konventioneller MRT bei 1.5 T und 3.0 T mit pMRT zeigte, dass der mit pMRT verbundene Signalverlust durch das höhere Grundsignal bei 3.0 T gegenüber 1.5 T mehr als kompensiert werden kann. Die kardiale MRT bei 3.0 T ohne und mit Einsatz der pMRT ist somit durchführbar und geeignet ist für die Beantwortung diagnostischer Fragestellungen und ermöglicht bei weiterem Optimierungsbedarf eine Verbesserung der Geschwindigkeit der Bildakquisition, der Effizienz des Untersuchungsablaufs und schließlich des Patientenkomforts.Cardiac MRI demands a high spatial and temporal resolution at scan duration as low as possible. The use of faster and stronger gradient coils is limited by physiologic constraints. Highfield-MRI at 3.0T and accelerated parallel imaging techniques (pMRI) potentially could improve the practicability and efficiency of cardiac mri due to a higher baseline signal as well as a shorter scan-times accompanied by a possible gain in spatial and temporal resolution. Major disadvantages are a higher load of energy into the tissue, an increased sensitivity to artefacts at 3.0 T and a decrease of signal intensity in pMRI. The complementary use of 3.0 T and pMRI might help to overcome these detriments. In order to examine the technical feasibility of cardiac MRI at 3.0 T and existing differences to 1.5 T 20 probands were examined with acquisition of SSFP- and FSE-sequences at both field strengths. For the examination of the feasibility of parallel imaging techniques in cardiac mri the SSFP-sequences were measured with and without pMRI at both field strengths. The acquired images were compared with regard to signal-to-noise, contrast-to-noise-ratio and image quality. This study demonstrates the general feasibility of cardiac MRI at 3.0 T with and without pMRI. In both Cine-SSFP- sequences and FSE-sequences an increase of SNR and CNR was found, depending on sequence type, weighting, scan-plane and heart segment. The image quality of conventionally acquired images ranged at both field strengths from “good” to “very good”, with a tendency towards a poorer image quality at 3.0 T due to increased artefacts. The Image quality was dependent on weighting and the sequence applied. The use of pMRI led to a significant decrease in scan time. At 1.5 T there was no significant difference between normal MRI images and images measured with pMRI with an overall quality of “good” – “very good”. Due to increased artefacts at 3.0 T pMRI the image quality was poorer compared to the non-accelerated images but sufficient for diagnostic evaluation. The comparison between 1.5 T non-accelerated-MRI and 3.0 T pMRI showed a significant higher signal at 3.0 T and consequently the capability of 3.0 T to compensate the loss of signal-intensity due to pMRI. In conclusion cardiac MRI at 3.0 is feasible with a significant increase in signal intensity and comparable image quality to 1.5 T. The complementary use of pMRI leads to a significant reduction of scan time and thus to an improvement in the patient’s comfort. Future optimization will lead to a further decrease of acquisition time and an improvement of the examination’s efficiency

Series of fast reperfusion with simultaneous proximal and distal aspiration in patients with acute ischemic stroke

Abstract Background Various endovascular techniques for the recanalization of large vessel occlusion in patients with acute ischemic stroke have been established. In this series a combined distal and proximal aspiration technique was used as a novel approach. The aim of this study was to investigate, whether this technique achieves reperfusion faster and if embolization in distal territories can be reduced. Results The success of the treatment was dependent on the localization of the clot. Fast reperfusion was achieved in all patients when the clot was located at the level of the middle cerebral artery. Aspiration failed when the vessel occlusion was located at the level of the carotid-T and subsequent rescue treatment was performed. Median groin puncture to reperfusion time was 20 min (range 9–66). No Embolization to new territories (ENT) and no intracerebral hemorrhage were observed. One patient died. In all other patients favorable neurological outcome was observed as measured by a modified Rankin score at discharge (mRS 0, range 0–1). Conclusion Simultaneous proximal and distal aspiration appears to be fast and effective. Furthermore, it reliably prevented ENT in patients with vessel occlusion at the level of the middle cerebral artery in a small cohort

Comprehensive cardiac magnetic resonance imaging at 3.0 Tesla: feasibility and implications for clinical applications

OBJECTIVE: The objective of this study was to examine the applicability of high magnetic field strengths for comprehensive functional and structural cardiac magnetic resonance imaging (MRI). SUBJECTS AND METHODS: Eighteen subjects underwent comprehensive cardiac MRI at 1.5 T and 3.0 T. The following imaging techniques were implemented: double and triple inversion prepared FSE for anatomic imaging, 4 different sets of echocardiographic-gated CINE strategies for functional and flow imaging, inversion prepared gradient echo for delayed enhancement imaging, T1-weighted segmented EPI for perfusion imaging and 2-dimensional (2-D) spiral, and volumetric SSFP for coronary artery imaging. RESULTS:: Use of 3 Tesla as opposed to 1.5 Tesla provided substantial baseline signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) improvements for anatomic (T1-weighted double IR: DeltaSNR = 29%, DeltaCNR = 20%, T2-weighted double IR: DeltaSNR = 39%, DeltaCNR = 33%, triple IR: DeltaSNR = 74%, DeltaCNR = 60%), functional (conventional CINE: DeltaSNR = 123%, DeltaCNR = 74%, accelerated CINE: DeltaSNR = 161%, DeltaCNR = 86%), myocardial tagging (DeltaSNRsystole = 54%, DeltaCNRsystole = 176%), phase contrast flow measurements (DeltaSNR = 79%), viability (DeltaSNR = 48%, DeltaCNR = 40%), perfusion (DeltaSNR = 109%, DeltaCNR = 87%), and breathhold coronary imaging (2-D spiral: DeltaSNRRCA = 54%, DeltaCNRRCA = 69%, 3-D SSFP: DeltaSNRRCA = 60%, DeltaCNRRCA = 126%), but also revealed image quality issues, which were successfully tackled by adiabatic radiofrequency pulses and parallel imaging. CONCLUSIONS: Cardiac MRI at 3.0 T is feasible for the comprehensive assessment of cardiac morphology and function, although SAR limitations and susceptibility effects remain a concern. The need for speed together with the SNR benefit at 3.0 T will motivate further advances in routine cardiac MRI while providing an image-quality advantage over imaging at 1.5 Tesla

Tailored CT angiography in follow-up after endovascular aneurysm repair (EVAR): combined dose reduction techniques.

Background Endovascular aneurysm repair (EVAR) requires lifelong surveillance by computed tomography angiography (CTA). This is attended by a substantial accumulation of radiation exposure. Iterative reconstruction (IR) has been introduced to approach dose reduction. Purpose To evaluate adaptive statistical iterative reconstruction (ASIR) at different levels of tube voltage concerning image quality and dose reduction potential in follow-up post EVAR. Material and Methods One hundred CTAs in 67 patients with EVAR were examined using five protocols: protocol A (n = 40) as biphasic standard using filtered back projection (FBP) at 120 kV; protocols B (n = 40), C (n = 10), and D1 (n = 5) biphasic using ASIR at 120, 100, and 80 kV, respectively; and protocol D2 (n = 5) with a monophasic splitbolus ASIR protocol at 80 kV. Image quality was assessed quantitatively and qualitatively. Applied doses were determined. Results Applied doses in ASIR protocols were significantly lower than FBP standard (up to 75%). Compared to protocol A, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) (e.g. arterial CNR intra-/extra-stent lumen: A = 35.4 ± 13.5, B = 34.2 ± 10.0, C = 29.6 ± 6.8, D1 = 32.1 ± 6.3, D2 = 40.8 ± 23.1) in protocol B were equal and in protocols C and D equal to partially inferior, however not decisive for diagnostic quality. Subjective image quality ratings in all protocols were good to excellent without impairments of diagnostic confidence (A-D2: 5), with high inter-rater agreement (60-100%). Conclusion ASIR contributes to significant dose reduction without decisive impairments of image quality and diagnostic confidence. We recommend an adapted follow-up introducing ASIR and combined low-kV in the long-term surveillance after EVAR

Placement of central venous port catheters and peripherally inserted central catheters in the routine clinical setting of a radiology department: analysis of costs and intervention duration learning curve.

Background Placement of central venous port catheters (CVPS) and peripherally inserted central catheters (PICC) is an integral component of state-of-the-art patient care. In the era of increasing cost awareness, it is desirable to have more information to comprehensively assess both procedures. Purpose To perform a retrospective analysis of interventional radiologic implantation of CVPS and PICC lines in a large patient population including a cost analysis of both methods as well as an investigation the learning curve in terms of the interventions' durations. Material and Methods All CVPS and PICC line related interventions performed in an interventional radiology department during a three-year period from January 2011 to December 2013 were examined. Documented patient data included sex, venous access site, and indication for CVPS or PICC placement. A cost analysis including intervention times was performed based on the prorated costs of equipment use, staff costs, and expenditures for disposables. The decrease in intervention duration in the course of time conformed to the learning curve. Results In total, 2987 interventions were performed by 16 radiologists: 1777 CVPS and 791 PICC lines. An average implantation took 22.5 ± 0.6 min (CVPS) and 10.1 ± 0.9 min (PICC lines). For CVPS, this average time was achieved by seven radiologists newly learning the procedures after performing 20 CVPS implantations. Total costs per implantation were €242 (CVPS) and €201 (PICC lines). Conclusion Interventional radiologic implantations of CVPS and PICC lines are well-established procedures, easy to learn by residents, and can be implanted at low costs