D Thomas

Low-field magnetic resonance imaging: increased safety for pacemaker patients?

AIMS The number of low-field (<0.5 T) magnetic resonance (MR) scanners installed worldwide is increasing due to a favourable cost and safety profile and improved patient comfort using an open-scanner design. Therefore, the aim of our study was to evaluate a strategy for the safe performance of magnetic resonance imaging (MRI) at a field strength of 0.2 T, in pacemaker (PM) patients without limitations on scan region, PM dependency, or the presence of abandoned leads. METHODS AND RESULTS One hundred and fourteen PM patients, including PM-dependent patients and patients with abandoned leads, examined at a 0.2 T MR scanner due to an urgent clinical need for an MRI examination, were evaluated. All PMs were reprogrammed before MRI: if heart rate was <60 bpm, the asynchronous mode (with a rate of 80 bpm) was programmed to avoid MR-induced inhibition; if heart rate was >60 bpm, sense-only mode (ODO/OVO/OAO) was used to avoid MR-induced competitive pacing and potential proarrhythmia. Patients were monitored with electrocardiogram (ECG) and pulse oximetry. All PMs were interrogated before and after MRI, including measurement of lead impedance, pacing capture threshold (PCT), and battery voltage. All MRI scans were completed safely. No induction of arrhythmias or inhibition of PM output occurred. There were no statistically significant changes in lead impedance, PCT, or battery voltage (P>0.05). CONCLUSION Low-field MRI of PM patients, including high-risk PM patients and MRI scan regions, can be performed with an acceptable risk-benefit ratio under controlled conditions.

Lymphatic Interventions for Treatment of Chylothorax

PURPOSE To determine effectiveness of lymphatic interventional procedures for treatment of chylothorax. MATERIAL AND METHODS Analysis of interventions performed from 2001 to 2014. RESULTS In 21 patients with therapy resistant chylothorax a lymphatic radiological intervention was attempted, which could be performed in 19 cases: 17 thoracic duct embolizations (15 transabdominal, one transzervical and one retrograde transvenous procedure), 2 percutaneous destructions of lymphatic vessels, one CT-guided injection of ethanol next to a duplicated thoracic duct. Fourteen of seventeen (82.3 %) of the technically successful embolizations lead to clinical cure. This encluded three patients with prior unsuccessful surgical thoracic duct ligation. Also the injection of ethanol was clinically effective. Complications were a bile peritonitis requiring operation, and one clinical deterioration of unknown cause. CONCLUSION Interventional lymphatic procedures allow for effective treatment in many cases of chylothorax, and should be considered early during treatment. KEY POINTS • Thoracic duct embolization is an effective treatment method for chylothorax. • If embolization is impossible, percutaneous lymphatic destruction or injection of sclerosants/tissue adhesive next to the thoracic duct may be tried.

Cardiovascular magnetic resonance imaging and clinical performance of somatostatin receptor positron emission tomography in cardiac sarcoidosis: CMR and SSTR PET in cardiac sarcoidosis

Cardiac affection constitutes a major limiting condition in systemic sarcoidosis. The primary objective of this study was to investigate the persistence rate of cardiac sarcoid involvement by cardiovascular magnetic resonance (CMR) imaging in patients diagnosed with cardiac sarcoidosis (CS). Moreover, we examined the additional insights into myocardial damages characteristics gained by somatostatin receptor scintigraphy.

Interventional Treatment of Acute Portal Vein Thrombosis

BACKGROUND Acute portal vein thrombosis is a potentially fatal condition. In symptomatic patients not responding to systemic anticoagulation, interventional procedures have emerged as an alternative to surgery. This study sought to retrospectively evaluate initial results of interventional treatment of acute portal vein thrombosis (aPVT) using a transjugular interventional approach. MATERIALS AND METHODS Between 2014 and 2016, 11 patients were treated because of aPVT (male: 7; female: 4; mean age: 41.06 years). All patients presented a rapid onset of symptoms without collateralization of portal flow as assessed by a CT scan at the time of admittance. The patients showed thrombotic occlusion of the main portal vein (11/11), the lienal vein (10/11) and the superior mesenteric vein (10/11). Different techniques for recanalization were employed: catheter thromboaspiration (1/9), AngioJet device (7/9), local-lysis-only (1/9) and TIPSS (7/9). Local lysis was administered using a dual (4/9) or single (5/9) catheter technique. The mean follow-up was 24.32 months. RESULTS In 9 patients transhepatic access was successful. Initially reduction of thrombus load and recanalization were achieved in all 9 cases with residual thrombi in PV (n = 3), SMV (n = 7), and IL (n = 5). In the collective undergoing interventional procedures (n = 9) rethrombosis and continuous abdominal pain were seen in one patient, and thrombus progression after successful recanalization was seen in another. Freedom from symptoms could be achieved in 6 patients. One patient developed peritoneal and pleural effusion, respiratory insufficiency and portosystemic collaterals. Both patients who could not undergo an interventional procedure developed a cavernous transformation of the portal vein. One of them also had continuous intermittent abdominal pain. CONCLUSION Interventional percutaneous approaches are able to improve patient outcome in patients with aPVT. It appears to be of utmost importance to not only remove/reduce the thrombotic material but to establish sufficient inflow and outflow by TIPS and simultaneous multi-catheter thrombolysis. KEY POINTS · Pharmacomechanic thrombectomy in combination with local thrombolysis is a feasible approach. · The transjugular transhepatic approach seems to be a safe procedure. · TIPSS and dual catheter lysis may support flow management. CITATION FORMAT · Wolter K, Decker G, Kuetting D et al. Interventional Treatment of Acute Portal Vein Thrombosis. Fortschr Röntgenstr 2018; 190: 740 - 746.

Epicardial adipose tissue, aortic stiffness and myocardial fibrosis in healthy individuals: a quantitative cardiac magnetic resonance study

Background Epicardial adipose tissue, aortic stiffness and myocardial fibrosis have been linked to cardiovascular risk and disease; however, often different modalities are used for their measurement. Cardiac magnetic resonance (CMR) may be used to determine these parameters in a single examination by the measurement of epicardial fat volumes (EFV), aortic pulse wave velocity (PWV) as a parameter of aortic stiffness, and T1-relaxation time (T1) as a marker for myocardial fibrosis. This quantitative CMR-study was performed to identify relationships between these parameters in healthy individuals and to correlate them with age, body mass index (BMI) and gender.

Clinical Cardiac MR at 3.0 Tesla using parallel RF transmission with patient-adaptive local RF shimming: initial experience

Purpose: The use of high-field MRI scanners has introduced new challenges for cardiac imaging, associated with B1- and B0-field inhomogeneities. A dual – source RF transmission system may help reduce dielectric effects, thus improving image contrast and reducing local SAR peaks of cardiac TSE and SSFP sequences, thereby allowing a shorter minimum TR and TE of SSFP sequences. Thus, the aim of our study was to evaluate the impact of dual – source parallel RF transmission with patient adaptive RF-shimming on image quality and diagnostic confidence for routine clinical CMR using a 3.0 T dual – channel transmit whole – body MRI system. Materials and Methods: A clinical 3.0 T MRI system (Achieva 3.0T-TX, Philips Healthcare, Best, Netherlands), equipped with a dual-source RF transmission system was used. The effect of parallel RF transmission with patient adaptive B1 shimming (multi transmit=MTx) vs. conventional (single transmit=STx) RF transmission on SSFP sequences and TSE Black-Blood (TSE BB) sequences was evaluated. Images were analyzed independently by two experienced readers for homogeneity and diagnostic confidence on a 4-point grading-scale. Also, the presence of off-resonance artefacts in the SSFP images was rated on a 4-point grading scale. CNR between interventricular septum and blood pool was determined. Results: A total of 21 patients were included into the study. For both, TSE BB and SSFP -images, the use of MTx resulted in a significant improvement of image homogeneity and diagnostic confidence in the left and right ventricle. As a side effect, off-resonance artefacts were significantly reduced in the acquired SSFP images. Interrater agreement for all ratings was very good. The quantitative measurements revealed a significant increase of CNR in the RF shimmed images using MTx compared to the images acquired with STx.((BR))Conclusions: Patient adaptive local RF-shimming using parallel dual source RF-transmission significantly improves image homogeneity, diagnostic confidence and contrast of cardiac SSFP and TSE BB sequences.