Philips (Netherlands)

To compare the diagnostic quality of deep learning (DL) super-resolution reconstructed breath-hold (BH) and free-breathing (FB) single-shot (SSH) black-blood T2-weighted short tau inversion recovery (STIR) imaging with standard BH T2-STIR in cardiovascular magnetic resonance (CMR). In this prospective study, short-axis BH and FB SSH T2-STIR were added to a standard cardiomyopathy CMR protocol at 1.5T, and DL super-resolution reconstruction was performed. Two readers evaluated diagnostic quality and certainty using a five-point Likert scale. Presence of focal edema was assessed on T2-weighted sequences, including standard T2-STIR and T2 mapping (both used for reference clinical assessment) as well as SSH T2 STIR and DL-SSH T2-STIR. Friedman test and one-way ANOVA were performed. Eighty-one participants (mean age: 54 ±20 years; 50 men) were included. No difference was found in edema detection between reference assessment and DL-SSH T2-STIR (both 26%, (21/81 participants)). Scan time was reduced by 63% for BH and 86% for FB DL-SSH T2-STIR compared to standard T2-STIR (90± 6s vs. 35± 3s vs. 243± 16s; p<.0001). BH and FB DL-SSH T2-STIR achieved lower artifact burden (5 [IQR, 4-5] vs. 4 [IQR, 4-5] vs. 4 [IQR, 3-5]; p<.0001), superior image contrast and sharpness compared to standard T2-STIR, especially in non-cooperative or arrhythmic participants. BH and FB DL-SSH T2-STIR imaging provided higher diagnostic certainty than standard T2-STIR (5 [IQR, 5-5] vs. 5 [IQR, 5-5] vs. 4 [IQR, 4-5]; p<.0001). Edema visibility was superior in BH DL-SSH compared to BH-SSH and standard T2-STIR (5 [IQR, 4.8-5] vs. 4 [IQR, 3.3-5] vs. 4 [IQR, 3-4.8]; p<.0001). Inter-rater agreement was substantial to excellent in the rating of edema visibility (BH DL-SSH T2-STIR, κ: 0.73 [95% CI: 0.44-1.0]; BH SSH T2-STIR, κ: 0.79 [95% CI: 0.66-0.97]; standard T2-STIR, κ: 0.86 [95% CI: 0.71-1.0]). Slice level-analysis showed that BH DL-SSH T2-STIR consistently provided superior image quality in apical slices compared to BH SSH and standard T2-STIR (4 [IQR, 4-5] vs. 4 [IQR, 4-4] vs. 4 [IQR, 3-4]; p<.0001). DL-SSH imaging enabled ultrafast T2-STIR acquisition and robust edema assessment in routine clinical CMR.

To evaluate the non-contrast-enhanced relaxation-enhanced angiography without contrast (REACT) sequence for the assessment of extrathoracic vessels in pediatric patients compared to contrast-enhanced (CE), multiphasic magnetic resonance angiography (MRA). In this prospective, single-center study, pediatric patients referred for clinically indicated contrast-enhanced MRI of various extrathoracic body regions underwent additional free-breathing REACT and multiphasic, free-breathing CE-MRA at 1.5 T (Philips Ingenia). REACT was acquired using Cartesian k-space order, except in the abdomen, where it was acquired using a radial stack of stars k-space sampling (REACT VANE). The acquisition time was recorded. Image quality (Likert scale 1-5, with 5 being the best) and vessel diameter were evaluated by two independent readers in four predefined vessels in each body region. Furthermore, a quantitative analysis of SNR and CNR was performed. 30 patients (age: 12.3 ± 4 years) successfully completed REACT and CE-MRA. The acquisition time for REACT was 2:49 ± 1:03 min, while abdominal REACT VANE required 4:51 ± 0:52 min. The CE-MRA acquisition time was 3:49 ± 1:03 min. The median image quality ratings were good to excellent (Likert scale 4-5) for both readers. No significant difference in the image quality ratings was found (p = 0.12 - 0.58). Interobserver agreement of image quality ratings of the two readers was moderate to substantial (Cohen's kappa REACT: 0.58, CE-MRA: 0.64). Vessel diameter measurements showed a strong correlation (r = 0.93) between REACT and CE-MRA with high intraclass correlation coefficients (REACT: 0.97, CE-MRA: 0.97). Quantitative analysis showed a higher venous SNR and higher arterial and venous CNR in REACT (p = 0.001-0.018). Given the good and comparable image quality, REACT can be useful in vascular imaging in children under free-breathing, while potentially eliminating the need for contrast agent injection. · MR angiography is widely used in pediatric imaging for vessel assessment.. · Contrast-enhanced MRA has limitations due to the use of gadolinium-based contrast agents.. · REACT is a novel contrast-free MRA technique performed during free breathing.. · REACT provides image quality comparable to contrast-enhanced free-breathing MRA.. · Spogis J, Tsiflikas I, Katemann C et al. Free-breathing non-contrast-enhanced flow-independent MR angiography using REACT: A prospective study for pediatric vessel assessment. Rofo 2026; 10.1055/a-2781-8861.

To evaluate the ability of spectral CT to non-invasively monitor liver temperature in vivo during thermal ablation. Under a protocol approved by the Institutional Animal Care and Use Committee, domestic swine (n = 3) underwent microwave ablation (MWA). Four thermocouples were percutaneously placed in the ablation region under ultrasound guidance. Single-probe MWA was performed for 5min at 65W. Sequential dual-layer spectral CT scans were collected at 1-min intervals during and after ablation (n = 16 scans/subject). Pre- and post-ablation contrast-enhanced CTs were acquired. Virtual monoenergetic images (70keV) were used to mask gas bubbles and metal artifacts and to identify and segment ROIs at the thermocouple tips. Electron density weighted (EDW), effective atomic number (Z-eff), and conventional CT results were associated with temperature using correlation analysis and polynomial curve fitting. Explanted ablation zones were sectioned perpendicular to the probe track, and gross pathology was analyzed. Twelve thermocouples were placed near the MWA probe shaft at a mean distance of 8.3mm (range 2.5-24.0mm). Maximum measurements for each thermocouple ranged from 46 to 99°C (overall range 29-99°C). Temperature measurements were compared to corresponding spectral CT imaging results (n = 192). At the thermocouple locations, the mean EDW was 103.9 ± 0.97 (range 98.5-105.8). A negative linear correlation was found between temperature and EDW (r = - 0.570, 95%CI [- 0.483 - 0.645], p < 0.001, root mean squared error = 8.05°C). This proof-of-concept study demonstrated the feasibility of monitoring temperature in vivo using spectral CT during thermal ablation. Intraprocedural temperature feedback may improve treatment margin identification and monitoring of nearby critical structures.

Reduced contrast media (CM) dose at elevated heart rates (HRs) poses a challenge for coronary artery disease (CAD) assessment. Using a dynamic phantom, we evaluated the performance of a vendor-specific coronary motion-compensated reconstruction (MCR) at various simulated HRs and reduced CM dose in low virtual monoenergetic images (VMIs) from coronary computed tomography angiography (CCTA). A clinical CCTA protocol was used to image a 5-mm artificial coronary artery, filled with 100% (400 Hounsfield units (HU)) and 50% CM dose, using a robotic arm for translation at six velocities (0-50mm/s, 10mm/s steps). Conventional images and VMIs (40-70keV, 10keV steps) were reconstructed without and with MCR. The study evaluated the MCR influence on motion area and contrast-to-noise ratio (CNR) of the resulting segmented arteries (motion area), with the static conventional reconstructed artery at 100% CM dose as the reference, and non-overlapping 95% confidence intervals with the reference indicating significant differences. At 50% CM dose, motion area increased significantly (up to 50%) at elevated velocities (≥ 30mm/s) without MCR, while no significant variations were observed with MCR. Additionally, without MCR, VMIs exhibited significant CNR decreases (up to 65%) at velocities ≥ 30mm/s. Only the combination of MCR and 40keV VMI achieved CNR comparable to the reference, regardless of HR. The combination of MCR with low VMIs enables 50% CM dose reduction, with similar motion area and CNR when compared to conventional CCTA with 100% CM dose. These parameter settings can potentially be used to optimize low CM dose CCTA at higher HRs.

<bold>Goal</bold> Cone-beam CT (CBCT) imaging in navigation bronchoscopy (NB) procedures is crucial for confirming the tool position relative to the lung lesion but can also function as a stand-alone NB modality. To enhance ease of use and directional support, CT scan information can now be fused with procedural CBCT imaging. This study explores the added value of these advanced imaging features and integrates novel ultra-low dose CBCT protocols. <bold>Method</bold> Thirty-eight patients referred for NB were prospectively enrolled in the AirWaze study <ext-link>NCT06046001</ext-link>. Pre-procedural CT scans were uploaded using investigational software (Philips) for airway segmentation, lesion and pathway planning. During the NB, this planning was fused with CBCT and overlayed with augmented fluoroscopy (AF). Ultra-low dose CBCT protocols were validated for tool position confirmation. <bold>Results:</bold> A total of 38 lung lesions with a median size of 15 mm (IQR 11.8-22.5 mm) were biopsied with CBCT, AF and software guidance (Figure 1). Combined with the advanced imaging features, ultra-low dose CBCT protocols for confirmation were as useful as regular CBCT protocols in 76% of the NBs, resulting in an average dose of 0.60 Gycm2 compared to 9.18 Gycm2 per spin. <bold>Conclusion:</bold> Applying advanced imaging features is technically feasible and support ease of use of CBCT NB procedures as a stand-alone modality. Ultra-low dose CBCT protocols are useful for most lesions and translates into a 93% dose reduction per spin. <fig><object-id>erj;66/suppl_69/PA1953/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>

BackgroundInterventional cardiovascular magnetic resonance imaging (MRI) offers real-time, radiation-free guidance for complex procedures such as myocardial ablation, marking a promising advance in electrophysiology. However, further development is limited by challenges in magnetic resonance (MR)-compatible instrument testing, MRI sequence validation, and accurate correlation with histopathology, hindered by the limitations of in vivo tissue evaluation.ObjectiveThis study investigated the feasibility of real-time MR-guided radiofrequency (RF) ablation in an MR-compatible isolated beating pig heart platform and characterized ablation lesions using MRI and histopathology.MethodsA heart from a pig slaughtered for human consumption was prepared under regulatory guidelines and connected to a custom-built, MR-compatible perfusion platform supporting left ventricular function in both Langendorff and working modes. Autologous heparinized blood circulated at physiological pressures and temperatures. MR-guided catheter navigation and RF ablation were performed on a Philips 3T scanner using active catheter tracking. Native T1 and T2 mapping were acquired before and after ablation. Lesions were confirmed by histologic analysis.ResultsRF ablation (50 W, 60 seconds) was successfully performed at 5 left ventricular sites. MRI showed focal reductions in T1 (936 ± 80 ms) surrounded by elevated T1 (1357 ± 18 ms) and T2 values (86 ± 10 ms) compared with nonablated myocardium (T1 1192 ± 26 ms; T2 66 ± 6 ms), consistent with necrosis and edema. Histology confirmed a necrotic core with a surrounding rim showing contraction band necrosis and erythrocyte extravasation.ConclusionThis study demonstrates the feasibility of real-time MR-guided ablation in a beating pig heart platform. The setup allows high-resolution lesion assessment and histologic correlation, supporting future developments in MR-guided therapies.

High-voltage unipolar square wave pulsed electric fields (PEFs) can cause cell membrane rupture and cell death during a process termed irreversible electroporation (IRE). PEF effects are influenced by pulse parameters like number of pulses (NP), voltage (PV), width (PW), and interval (PI). This study systematically evaluates their effects on the conductivity and relative conductivity changes between untreated and PEF-treated regions of potato tissue across a frequency range of 1 Hz to 5 MHz by means of electrochemical impedance spectroscopy (EIS), using a custom-made four-point EIS probe with RG58/U coaxial cables. Potatoes were chosen as a plant-based PEF model to reduce animal experiments and untreated tissue showed minimal conductivity variation across regions. Relative conductivity changes were maximal at 1000 Hz. At 1000 Hz, significant conductivity differences between untreated and PEF-treated regions were observed from PV = 200 V, NP = 10, PW = 10 µs, and PI = 50 ms onwards (most significant changes occurred for PV = 700 V; NP = 70; PW = 70 µs; PI = 250 ms and 500 ms). Our results may be beneficial for multiphysics modelling of IRE with specific electrical properties, conductivity mapping with optimal contrast—such as in electrical impedance tomography—and development of IRE procedures.

This paper introduces a novel approach that integrates future closest point predictions into the distance constraints of a collision avoidance controller, leveraging convex hulls with closest point distance calculations. By addressing abrupt shifts in closest points, this method effectively reduces collision risks and enhances controller performance. Applied to an Image Guided Therapy robot and validated through simulations and user experiments, the framework demonstrates improved distance prediction accuracy, smoother trajectories, and safer navigation near obstacles.

Medical ultrasound is a diagnostic imaging modality used for visualizing internal organs; the frequencies typically used are 2-10 MHz. Scanning acoustic microscopy (SAM) is a form of ultrasound where frequencies typically exceed 50 MHz. Increasing the acoustic frequency increases the specimen's spatial resolution but reduces the imaging depth. The advantages of using SAM over conventional light and electron microscopy include the ability to image cells and tissues without any preparation that could kill or alter them, providing a more accurate representation of the specimen. After scanning the specimen, acoustic signals are merged into an image on the basis of changes in the impedance mismatch between the immersion fluid and the specimens. The acoustic parameters determining the image quality are absorption and scattering. Surface scans can assess surface characteristics of the specimen. SAM is also capable of elastography, that is, studying elastic properties to discern differences between healthy and affected tissues. SAM has significant potential for detection/analysis in research and clinical studies.

Fiber Optic RealShape (FORS) is a novel technology using embedded optical fiber, aiming to visualize the full 3D shape of interventional devices, such as catheters and guidewires in real time. Visualized within the context of anatomical data, often imaged by a combination of X-ray and contrast-enhanced CT (computed tomography), the 3D shape of the interventional device provides intuitive guidance to clinicians without being exposed to radiation and assists navigation of devices to challenging targets. The ability to store shape data during procedures is essential to gain technical insights and to improve the accuracy and robustness of the technology, which can help to improve certain operation aspects during surgery. However, continuous shape sensing can incur large data streams that can limit the amount of data stored during interventions and hamper the effectiveness of postoperative data analysis. This paper aims to alleviate the data demands of shape sensing devices by proposing a data compression algorithm. We investigate two cases: 1) compression when full samples are sensed at the encoding side, and 2) combined compression and optimization of sampling points for sensing. The presented study achieves these objectives through 1) using Principal Components Analysis (PCA), and 2) compressed sensing employing a data-tailored transform based on PCA. The developed intelligent compression algorithm can compress the position-based shape sensing data by retaining only 2% of the original data points while preserving high reconstruction quality of the shapes. When full samples are available, the proposed technique achieves a compression factor of 67.5 at acceptable loss levels.