Rationale for fluoroscopic guidance in spine injections

Spine injections are commonly performed in the treatment of back pain. The purpose of this article is to review the current literature surrounding image guided spine injections focusing on scenarios where fluoroscopic guidance can be advantageous in addition to discussing similarities among the different modalities.

Establishment of Diagnostic Reference Levels in Cone Beam Computed Tomography Scans in the United Arab Emirates

This study aimed to address the knowledge gap in assessing the radiation doses from cone beam computed tomography (CBCT) procedures, establishing a typical value, and estimating effective and organ doses. A total of 340 patients aged 18-80 years were included in this study. Organ doses were estimated using VirtualDose IR software. The typical values were based on median values estimated as 1000 mGy cm². The mean ED (µSv) per procedure was 149.5 ± 56, and the mean of the peak skin dose during the CBCT examination was 39.29 mGy. The highest organ dose was received by the salivary glands (2.71 mGy), the extrathoracic region (1.64 mGy), thyroid (1.24 mGy) and eyes (0.61 mGy). The patients' doses were higher than in previous studies. Staff awareness, education, training and dose optimisation are highly recommended. With the establishment of local DRLs, patient dosages can be reduced successfully without compromising image quality.

Source-detector trajectory optimization in cone-beam computed tomography: a comprehensive review on today’s state-of-the-art

Cone-beam computed tomography (CBCT) imaging is becoming increasingly important for a wide range of applications such as image-guided surgery, image-guided radiation therapy as well as diagnostic imaging such as breast and orthopaedic imaging. The potential benefits of non-circular source-detector trajectories was recognized in early work to improve the completeness of CBCT sampling and extend the field of view (FOV). Another important feature of interventional imaging is that prior knowledge of patient anatomy such as a preoperative CBCT or prior CT is commonly available. This provides the opportunity to integrate such prior information into the image acquisition process by customized CBCT source-detector trajectories. Such customized trajectories can be designed in order to optimize task-specific imaging performance, providing intervention or patient-specific imaging settings. The recently developed robotic CBCT C-arms as well as novel multi-source CBCT imaging systems with additional degrees of freedom provide the possibility to largely expand the scanning geometries beyond the conventional circular source-detector trajectory. This recent development has inspired the research community to innovate enhanced image quality by modifying image geometry, as opposed to hardware or algorithms. The recently proposed techniques in this field facilitate image quality improvement, FOV extension, radiation dose reduction, metal artifact reduction as well as 3D imaging under kinematic constraints. Because of the great practical value and the increasing importance of CBCT imaging in image-guided therapy for clinical and preclinical applications as well as in industry, this paper focuses on the review and discussion of the available literature in the CBCT trajectory optimization field. To the best of our knowledge, this paper is the first study that provides an exhaustive literature review regarding customized CBCT algorithms and tries to update the community with the clarification of in-depth information on the current progress and future trends.

Optimized Intraoperative Imaging for Stereotactic Planning with a Multiaxial Robotic C-arm System: Technical Note and Case Series

BACKGROUND

 The preoperative preparation of the planning dataset for frame-based stereotactic brain biopsy is often associated with logistical effort and burden on the patient. Intraoperative imaging modalities need to be investigated to overcome these limitations.

OBJECTIVE

 The objective of the study was to develop and apply a new method for the intraoperative acquisition of the planning dataset with the multiaxial robotic C-arm system Artis zeego.

METHODS

 An indication-customized dose-reduced protocol for Artis zeego was developed and implemented into the workflow. A sample of 14 patients who had undergone intraoperative imaging with Artis zeego was analyzed. A sample of 10 patients with conventional preoperative imaging by cranial computed tomography (CT) was used as a control group. Outcomes were compared with regard to target deviation, diagnostic value of the biopsies, complications, and procedure time.

RESULTS

 In all patients, a suitable intraoperative planning dataset could be acquired with Artis zeego. Total procedure time was shorter for the Artis zeego group (p = 0.01), whereas time in the operating room area was longer in the Artis zeego group (p = 0.04). Biopsy results were diagnostic in 12 patients (86%) in the Artis zeego group and in 8 patients (80%) in the control group. There were no significant differences in target size, trajectory length, or target deviation.

CONCLUSION

 Intraoperative imaging for frame-based stereotactic brain biopsy with Artis zeego is an easy and feasible method. Accuracy is comparable to conventional CT, whereas radiation exposure could be additionally reduced. It allows a significant reduction of the total procedure length and improves the comfort for the patient and staff.

Validation of standing cone beam computed tomography for diagnosing subchondral fetlock pathology in the Thoroughbred racehorse

BACKGROUND

Subchondral bone pathology is common in Thoroughbred racehorses and believed to precede more serious injury. Early identification of pathology is critical to allow for intervention.

OBJECTIVES

To determine interobserver variability of fetlock subchondral bone lesions using cone beam and fan beam computed tomography (CBCT, FBCT) and to validate a robotics-controlled CBCT to identify fetlock subchondral bone pathology in the Thoroughbred racehorse.

STUDY DESIGN

Prospective cohort study.

METHODS

FBCT and CBCT images were acquired of 25 metacarpo-/metatarsophalangeal joints of Thoroughbred racehorses. Images were analysed for subchondral bone lesions commonly identified in Thoroughbred fetlocks by an imaging specialist and surgery specialist. Interobserver and intermodality equivalence were determined with a Pearson correlation analysis and Bland-Altman equivalence test.

RESULTS

Interobserver FBCT correlation was significant (P < .05) for 19 of 25 variables (Pearson R mean 0.77). Concordance was significant for all 25 variables (Bland Altman average difference 0.28 ± 0.21 mm). Interobserver CBCT correlation was significant for 21 of 25 variables (Pearson R mean 0.73). Concordance was significant for all variables (Bland Altman average difference 0.07 ± 1.90 mm). Intermodality (FBCT vs CBCT) correlation and concordance was significant for all variables as interpreted by the radiologist (Pearson R mean of 0.72, Bland Altman average difference 0.21 ± 0.47 mm). Intermodality correlation was significant for 19 of 25 variables as interpreted by the surgeon (Pearson R mean of 0.72). Concordance was significant for all variables (Bland Altman average difference 0.49 ± 0.52 mm).

MAIN LIMITATIONS

Neither FBCT nor CBCT images were compared with other imaging modalities/histopathology; limited number of cases included; inconsistent agreement of small lesions in specific categories.

CONCLUSIONS

Standing CBCT is a valid diagnostic modality to identify subchondral bone lesions in Thoroughbred fetlocks. This technology may provide valuable information regarding the development and progression of fetlock pathology and yield insight into predisposing factors leading to more severe pathology.

Task-driven source-detector trajectories in cone-beam computed tomography: II. Application to neuroradiology

We apply the methodology detailed in "Task-driven source-detector trajectories in cone-beam computed tomography: I. Theory and methods" by Stayman et al. for task-driven optimization of source-detector orbits in cone-beam computed tomography (CBCT) to scenarios emulating imaging tasks in interventional neuroradiology. The task-driven imaging framework is used to optimize the CBCT source-detector trajectory by maximizing the detectability index, d ' . The approach was applied to simulated cases of endovascular embolization of an aneurysm and arteriovenous malformation and was translated to real data first using a CBCT test bench followed by implementation on an interventional robotic C-arm. Task-driven trajectories were found to generally favor higher fidelity (i.e., less noisy) views, with an average increase in d ' ranging from 7% to 28%. Visually, this resulted in improved conspicuity of particular stimuli by reducing the noise and altering the noise correlation to a form distinct from the spatial frequencies associated with the imaging task. The improvements in detectability and the demonstration of the task-driven workflow using a real interventional imaging system show the potential of the task-driven imaging framework to improve imaging performance on motorized, multiaxis C-arms in neuroradiology.

Current Trends in Sinonasal Imaging

As endoscopic sinus surgery (ESS) has evolved since its introduction to the United States, so has technology for imaging the sinonasal cavities. Although imaging is most frequently performed for evaluating chronic sinusitis refractory to medical therapy, its uses have expanded beyond inflammatory sinus disease. Multidetector Computed Tomography is the current workhorse for both diagnosis and preoperative planning in prospective ESS patients, while MR imaging remains a complementary tool for evaluating suspected tumors or intracranial and orbital complications of rhinosinusitis. In this article, the authors review current trends and potential future directions in the use of these modalities for sinus imaging.

Brain radiation doses to patients in an interventional neuroradiology laboratory

BACKGROUND AND PURPOSE

In 2011, the International Commission on Radiologic Protection established an absorbed-dose threshold to the brain of 0.5 Gy as likely to produce cerebrovascular disease. In this paper, the authors investigated the brain doses delivered to patients during clinical neuroradiology procedures in a university hospital.

MATERIALS AND METHODS

The radiation dose delivered to the brain was investigated in 99 diagnostic and therapeutic interventional neuroradiology procedures. Brain doses were calculated in a mathematic model of an adult standard anthropomorphic phantom by using the technical and radiation dose data of an x-ray biplane system submitted to regular quality controls and calibration programs.

RESULTS

For cerebral embolizations, brain doses resulted in a maximum value of 1.7 Gy, with an average value of 500 mGy. Median and third quartile resulted in 400 and 856 mGy, respectively. For cerebral angiography, the average dose in the brain was 100 mGy.

CONCLUSIONS

This work supports the International Commission on Radiologic Protection recommendation on enhancing optimization when doses to the brain could be higher than 0.5 Gy. Radiation doses should be recorded for all patients and kept as low as reasonably achievable. For pediatric patients and young adults, an individual evaluation of brain doses could be appropriate.