Visualization Of Small Anatomic Structures Research Articles

High Spatial-Resolution Skull Base Imaging With Photon-Counting Computed Tomography and Energy-Integrating Computed Tomography: A Comparative Phantom Study.

Photon-counting computed tomography (PCCT) offers better high-resolution and noise performance than energy integrating detector (EID) CT. In this work, we compared both technologies for imaging of the temporal bone and skull base. A clinical PCCT system and 3 clinical EID CT scanners were used to image the American College of Radiology image quality phantom using a clinical imaging protocol with matched CTDI vol (CT dose index-volume) of 25 mGy. Images were used to characterize the image quality of each system across a series of high-resolution reconstruction options. Noise was calculated from the noise power spectrum, whereas resolution was quantified with a bone insert by calculating a task transfer function. Images of an anthropomorphic skull phantom and 2 patient cases were examined for visualization of small anatomical structures. Across measured conditions, PCCT had a comparable or smaller average noise magnitude (120 Hounsfield units [HU]) to the EID systems (144-326 HU). Photon-counting CT also had comparable resolution (task transfer function f25 : 1.60 mm -1 ) to the EID systems (1.34-1.77 mm -1 ). Imaging results supported quantitative findings as PCCT more clearly showed the 12-lp/cm bars from the fourth section of the American College of Radiology phantom and better represented the vestibular aqueduct and oval and round windows when compared with the EID scanners. A clinical PCCT system was able to image the temporal bone and skull base with improved spatial resolution and lower noise than clinical EID CT systems at matched dose.

Editorial Comment: Ultrahigh-Resolution Photon-Counting Detector CT Improves Visualization of Small Anatomic Structures of the Lungs.

Editorial Comment: Ultrahigh-Resolution Photon-Counting Detector CT Improves Visualization of Small Anatomic Structures of the LungsAnle Yu, MD1Audio Available | Share

Pediatric Urolithiasis: Current Surgical Strategies and Future Perspectives.

New technological innovations and cutting-edge techniques have led to important changes in the surgical management of pediatric urolithiasis. Miniaturized technologies and minimally invasive approaches have been increasingly used in children with urinary stones to minimize surgical complications and improve patient outcomes. Moreover, the new computer technologies of the digital era have been opening new horizons for the preoperative planning and surgical treatment of children with urinary calculi. Three-dimensional modeling reconstructions, virtual, augmented, and mixed reality are rapidly approaching the surgical practice, equipping surgeons with powerful instruments to enhance the real-time intraoperative visualization of normal and pathological structures. The broad range of possibilities offered by these technological innovations in the adult population finds increasing applications in pediatrics, offering a more detailed visualization of small anatomical structures. This review illustrates the most promising techniques and devices to enhance the surgical treatment of pediatric urolithiasis in children, aiming to favor an early adoption and to stimulate more research on this topic.

The Value of 3 Tesla Field Strength for Musculoskeletal Magnetic Resonance Imaging.

Musculoskeletal magnetic resonance imaging (MRI) is a careful negotiation between spatial, temporal, and contrast resolution, which builds the foundation for diagnostic performance and value. Many aspects of musculoskeletal MRI can improve the image quality and increase the acquisition speed; however, 3.0-T field strength has the highest impact within the current diagnostic range. In addition to the favorable attributes of 3.0-T field strength translating into high temporal, spatial, and contrast resolution, many 3.0-T MRI systems yield additional gains through high-performance gradients systems and radiofrequency pulse transmission technology, advanced multichannel receiver technology, and high-end surface coils. Compared with 1.5 T, 3.0-T MRI systems yield approximately 2-fold higher signal-to-noise ratios, enabling 4 times faster data acquisition or double the matrix size. Clinically, 3.0-T field strength translates into markedly higher scan efficiency, better image quality, more accurate visualization of small anatomic structures and abnormalities, and the ability to offer high-end applications, such as quantitative MRI and magnetic resonance neurography. Challenges of 3.0-T MRI include higher magnetic susceptibility, chemical shift, dielectric effects, and higher radiofrequency energy deposition, which can be managed successfully. The higher total cost of ownership of 3.0-T MRI systems can be offset by shorter musculoskeletal MRI examinations, higher-quality examinations, and utilization of advanced MRI techniques, which then can achieve higher gains and value than lower field systems. We provide a practice-focused review of the value of 3.0-T field strength for musculoskeletal MRI, practical solutions to challenges, and illustrations of a wide spectrum of gainful clinical applications.

Assessment of image quality and dose calculation accuracy on kV CBCT, MV CBCT, and MV CT images for urgent palliative radiotherapy treatments.

A clinical workflow was developed for urgent palliative radiotherapy treatments that integrates patient simulation, planning, quality assurance, and treatment in one 30‐minute session. This has been successfully tested and implemented clinically on a linac with MV CBCT capabilities. To make this approach available to all clinics equipped with common imaging systems, dose calculation accuracy based on treatment sites was assessed for other imaging units. We evaluated the feasibility of palliative treatment planning using on‐board imaging with respect to image quality and technical challenges. The purpose was to test multiple systems using their commercial setup, disregarding any additional in‐house development. kV CT, kV CBCT, MV CBCT, and MV CT images of water and anthropomorphic phantoms were acquired on five different imaging units (Philips MX8000 CT Scanner, and Varian TrueBeam, Elekta VersaHD, Siemens Artiste, and Accuray Tomotherapy linacs). Image quality (noise, contrast, uniformity, spatial resolution) was evaluated and compared across all machines. Using individual image value to density calibrations, dose calculation accuracies for simple treatment plans were assessed for the same phantom images. Finally, image artifacts on clinical patient images were evaluated and compared among the machines. Image contrast to visualize bony anatomy was sufficient on all machines. Despite a high noise level and low contrast, MV CT images provided the most accurate treatment plans relative to kV CT‐based planning. Spatial resolution was poorest for MV CBCT, but did not limit the visualization of small anatomical structures. A comparison of treatment plans showed that monitor units calculated based on a prescription point were within 5% difference relative to kV CT‐based plans for all machines and all studied treatment sites (brain, neck, and pelvis). Local dose differences >5% were found near the phantom edges. The gamma index for 3%/3 mm criteria was ≥95% in most cases. Best dose calculation results were obtained when the treatment isocenter was near the image isocenter for all machines. A large field of view and immediate image export to the treatment planning system were essential for a smooth workflow and were not provided on all devices. Based on this phantom study, image quality of the studied kV CBCT, MV CBCT, and MV CT on‐board imaging devices was sufficient for treatment planning in all tested cases. Treatment plans provided dose calculation accuracies within an acceptable range for simple, urgently planned palliative treatments. However, dose calculation accuracy was compromised towards the edges of an image. Feasibility for clinical implementation should be assessed separately and may be complicated by machine specific features. Image artifacts in patient images and the effect on dose calculation accuracy should be assessed in a separate, machine‐specific study.PACS number(s): 87.55.D‐, 87.57.C‐, 87.57.Q‐

High Definition Optical System for Microsurgical Heterotopic Heart Transplantation in Rats

BackgroundClinical and experimental cardiovascular surgery as well as other surgical disciplines may require visualization and manipulation of small anatomic structures. A high-definition optical system was developed for magnification and illumination as an alternative to surgical loupes or a traditional operating microscope. Materials and MethodsA video telescopic optical imaging system that provided a high-definition and magnification of the surgical field was used for visualization of small anatomic structures and as an aid to the performance of small vessel anastomoses in a series of 10 heterotopic heart transplants (HHTx) in rats. ResultsThe video telescopic optical system was easy to manipulate and comfortable to use, and provided high-definition images for magnification of anatomic structures while performing microvascular cardiac surgery in a small animal model of HHTx in rats. Fatigue and neck problems for the surgeon were reduced. ConclusionsThe video telescopic imaging system provided high definition and magnification of the surgical field, and was used for visualization of small anatomic structures and as an aid to the performance of small vessel anastomoses. The system is an alternative to surgical loupes or a traditional operating microscope, and was used for the first time in microvascular cardiac surgery in a rat HHTx model.

Discriminant analysis of texture data applied to the ultrasonic characterization of diffuse liver disease

A grey-scale display system for ultrasound contact B-scanning has been developed that produces six shades of grey on a high resolution storage oscilloscope. The grey shades are displayed by varying the density distribution of dots of a constant intensity. The system design and clinical results are presented. Advantages of our system are: 1. the non-degraded image is immediately displayed as the scan is performed, 2. the writing speed is faster than most scan converter tube systems so that many closely spaced scans can be rapidly performed in order to improve visualization of small anatomic structures, and 3. images comparable to those of scan converter display systems are produced at a significantly lower equipment cost.

Ultrasound grey scale display on storage oscilloscope system

A grey-scale display system for ultrasound contact B-scanning has been developed that produces six shades of grey on a high resolution storage oscilloscope. The grey shades are displayed by varying the density distribution of dots of a constant intensity. The system design and clinical results are presented. Advantages of our system are: 1. the non-degraded image is immediately displayed as the scan is performed, 2. the writing speed is faster than most scan converter tube systems so that many closely spaced scans can be rapidly performed in order to improve visualization of small anatomic structures, and 3. images comparable to those of scan converter display systems are produced at a significantly lower equipment cost.