Katharina Fischbach

Irreversible Electroporation (IRE): Standardization of Terminology and Reporting Criteria for Analysis and Comparison

Summary Background Irreversible electroporation (IRE) as newer ablation modality has been introduced and its clinical niche is under investigation. At present just one IRE system has been approved for clinical use and is currently commercially available (NanoKnife® system). In 2014, the International Working Group on Image-Guided Tumor Ablation updated the recommendation about standardization of terms and reporting criteria for image-guided tumor ablation. The IRE method is not covered in detail. But the non-thermal IRE method and the NanoKnife System differ fundamentally from established ablations techniques, especially thermal approaches, e.g. radio frequency ablation (RFA). Material/Methods As numerous publications on IRE with varying terminology exist so far – with numbers continuously increasing – standardized terms and reporting criteria of IRE are needed urgently. The use of standardized terminology may then allow for a better inter-study comparison of the methodology applied as well as results achieved. Results Thus, the main objective of this document is to supplement the updated recommendation for image-guided tumor ablation by outlining a standardized set of terminology for the IRE procedure with the NanoKnife Sytem as well as address essential clinical and technical informations that should be provided when reporting on IRE tumor ablation. Conclusions We emphasize that the usage of all above recommended reporting criteria and terms can make IRE ablation reports comparable and provide treatment transparency to assess the current value of IRE and provide further development.

Sensory perceptions of individuals exposed to the static field of a 7T MRI: A controlled blinded study

To determine the subjective experience of subjects undergoing 7T magnetic resonance imaging (MRI) compared to a mock scanner with no magnetic field.

Accuracy of applicator tip reconstruction in MRI-guided interstitial 192Ir-high-dose-rate brachytherapy of liver tumors.

BACKGROUND AND PURPOSE To evaluate the reconstruction accuracy of brachytherapy (BT) applicators tips in vitro and in vivo in MRI-guided (192)Ir-high-dose-rate (HDR)-BT of inoperable liver tumors. MATERIALS AND METHODS Reconstruction accuracy of plastic BT applicators, visualized by nitinol inserts, was assessed in MRI phantom measurements and in MRI (192)Ir-HDR-BT treatment planning datasets of 45 patients employing CT co-registration and vector decomposition. Conspicuity, short-term dislocation, and reconstruction errors were assessed in the clinical data. The clinical effect of applicator reconstruction accuracy was determined in follow-up MRI data. RESULTS Applicator reconstruction accuracy was 1.6±0.5 mm in the phantom measurements. In the clinical MRI datasets applicator conspicuity was rated good/optimal in ⩾72% of cases. 16/129 applicators showed not time dependent deviation in between MRI/CT acquisition (p>0.1). Reconstruction accuracy was 5.5±2.8 mm, and the average image co-registration error was 3.1±0.9 mm. Vector decomposition revealed no preferred direction of reconstruction errors. In the follow-up data deviation of planned dose distribution and irradiation effect was 6.9±3.3 mm matching the mean co-registration error (6.5±2.5 mm; p>0.1). CONCLUSION Applicator reconstruction accuracy in vitro conforms to AAPM TG 56 standard. Nitinol-inserts are feasible for applicator visualization and yield good conspicuity in MRI treatment planning data. No preferred direction of reconstruction errors were found in vivo.

Right heart function interacts with left ventricular remodeling after CRT: A pressure volume loop study

BACKGROUND Right ventricular (RV) dysfunction is recognized as a cardinal prognostic marker in systolic heart failure patients. Conflicting data exist on the interaction of RV function and left ventricular (LV) reverse remodeling after cardiac resynchronization therapy (CRT). This prospective monocentric trial was set up to assess the predictive value of baseline RV function and corresponding RV-pulmonary artery (PA) coupling on LV reverse remodeling after CRT. METHODS 110 patients with a CRT indication were prospectively enrolled. RV function and RV-PA interaction were analyzed at baseline using echocardiographic and invasive pressure-volume loop catheter approach. The primary endpoint was reverse LV remodeling (CRT-responder) defined as a reduction in LV end-systolic volume of ≥15% at 6 months. RESULTS Responders had higher RV-PA coupling ratios (single-beat end-systolic elastance/PA elastance: Ees/Ea) at baseline, which corresponded to smaller RVs with better ejection fraction and lower afterload. After multivariate adjustment, the baseline Ees/Ea remained an independent predictor for LV response (OR 14.0 [1.5-130.8], p = 0.021). Normal coupling (Ees/Ea ≥ 1) was associated with higher responder rates (RR) (86%). Progressive uncoupling was associated with lower LV-RR (Ees/Ea ≤ 1-0.5: 57%, and Ees/Ea < 0.5: 32%, p < 0.001), corresponded with higher degrees of LV impairment and severity of mitral regurgitation, and was independently associated with an adverse outcome. CONCLUSIONS A higher baseline RV-PA coupling, reflecting a lower degree of LV-induced pulmonary hypertension and secondary RV-dysfunction, is associated with an improved LV-reverse remodeling and is independently associated with better prognosis. The value of RV-PA ratio as potential guide for CRT patient selection warrants further investigation. Clinical Trial Registration - URL: http://www.drks.de. Unique Identifier: DRKS00011133.

Cardiac Magnetic Resonance Imaging Using an Open 1.0T MR Platform: A Comparative Study with a 1.5T Tunnel System

Summary Background Cardiac magnetic resonance imaging (cMRI) has become the non-invasive reference standard for the evaluation of cardiac function and viability. The introduction of open, high-field, 1.0T (HFO) MR scanners offers advantages for examinations of obese, claustrophobic and paediatric patients. The aim of our study was to compare standard cMRI sequences from an HFO scanner and those from a cylindrical, 1.5T MR system. Material/Method Fifteen volunteers underwent cMRI both in an open HFO and in a cylindrical MR system. The protocol consisted of cine and unenhanced tissue sequences. The signal-to-noise ratio (SNR) for each sequence and blood-myocardium contrast for the cine sequences were assessed. Image quality and artefacts were rated. The location and number of non-diagnostic segments was determined. Volunteers’ tolerance to examinations in both scanners was investigated. Results SNR was significantly lower in the HFO scanner (all p<0.001). However, the contrast of the cine sequence was significantly higher in the HFO platform compared to the 1.5T MR scanner (0.685±0.41 vs. 0.611±0.54; p<0.001). Image quality was comparable for all sequences (all p>0.05). Overall, only few non-diagnostic myocardial segments were recorded: 6/960 (0.6%) by the HFO and 17/960 (1.8%) segments by the cylindrical system. The volunteers expressed a preference for the open MR system (p<0.01). Conclusions Standard cardiac MRI sequences in an HFO platform offer a high image quality that is comparable to the quality of images acquired in a cylindrical 1.5T MR scanner. An open scanner design may potentially improve tolerance of cardiac MRI and therefore allow to examine an even broader patient spectrum.

Kommentar zur Sirflox-Studie

Hintergrund und Methodik. Y-90-Radioembolisation ist ein interventionelles Verfahren, bei dem ein anMikrosphären gekoppelter β-Strahler zur Behandlung primärer oder sekundärer Lebermalignome selektiv über die Leberarterie appliziert wird. SIRFLOX ist eine prospektive Multizenterstudie, die als Phase III konzipiert den additiven Wert der Y-90-Radioembolisation mit StärkeMikrosphären (Sirspheres®) bei nicht resektablen Lebermetastasen des kolorektalen Karzinoms untersucht hat. Eingeschlossen wurden 530 chemonaive Patienten, die mit mFolFox6 (optional kombiniert mit Bevazicumab) behandelt und nach Y-90-Radioembolisation oder keine Radioembolisation randomisiert wurden. Primärer Endpunkt war das progressionsfreie Überleben (PFS; unabhängige Begutachtung nach RECIST 1.0) und sekundäre Endpunkte unter anderem PFS in der Leber sowie Gesamtüberleben. Eingeschlossen wurden unter anderem Patienten mit extrahepatischer Metastasierung (bis zu <5 Lungenmetastasen ≤1 cm oder singuläre Lungenmetastase ≤1,7 cm oder Lymphknotenmetastasen <2 cm in einer anatomischen Region).