Avanto mri system

All scans were performed on a 1.5-tesla Siemens Avanto MRI system using the standard quadrature birdcage transmit/receive head coil. The imaging protocol used a T2-weighted fast spin-echo in the transverse plane. The T2-weighted sequence is a fundamental pulse sequence in MRI that highlights variations in the T2 relaxation time among different tissues. The raw data required for image reconstruction were captured in multiple successive passes, providing benefits such as shorter effective echo time, narrower bandwidth, reduced T2 decay, and fewer artifacts. To achieve a balance between scan time reduction and optimal image spatial resolution, several factors were adjusted. The field-of-view (FOV) was reduced to 217 mm, compared to the standardized FOV of 230 mm. The FOV phase was 93.88% instead of the standardized FOV phase of 90.6%. Additionally, phase oversampling was increased to enhance the signal-to-noise ratio.

A video of melon deformations can be found online (Video 3). To visualize the anatomy of the head, a dead specimen was scanned in a 1.5T Siemens Avanto MRI system (Siemens Medical Solutions, Germany). A Flash 3D T1 weighted pulse-sequence with the following parameters was used: TR 14.8 ms, TE 3.38 ms, α = 15°, NEX = 3, spatial resolution = 0.64 × 0.64 × 0.75 mm. Following acquisition, segmentation and modeling were done using Amira 5.3.3 (Visualization Science Group, Germany).

Following IRB approval and informed consent, multimodality imaging of five patients undergoing RT for non‐small cell lung cancer (NSCLC) acquired before treatment and at 5 weeks after initiating treatment was retrospectively analyzed. For each patient, non‐cardiac‐gated free‐breathing four‐dimensional computed tomography (4D‐CT) and T1 volumetric interpolated breath‐hold examination (VIBE) pre‐ and post‐contrast MR images in both inspiration and expiration were obtained. A few patients did not have full datasets: one patient lacked pre‐contrast MR at expiration and two patients lacked pre‐contrast MR at inspiration. CT data at the 0% and 50% respiratory cycle were selected as inspiration and expiration, respectively. Table 1 summarizes the data available for each scenario. 4D‐CT scans were obtained on a Brilliance Big Bore scanner (Philips Healthcare, Cambridge, MA, USA) using the following parameters: 397 mAs, 120 kVp, and 3 mm thickness. T1 VIBE MRI scans were performed with a 1.5T Avanto MRI System (Siemens, Germany) with the following parameters:nTime to Echo (TE) 1.28 ms, Repetition Time (TR) 3.56 ms, Echo Train Length (ETL) 1, slice thickness 2 mm, flip angle 12°, contrast agent 18 ml gadopentetate dimeglumine.