Synthetic interpolated DSA for radiation exposure reduction via gamma variate contrast flow modeling: a retrospective cohort study.

BACKGROUND: Digital subtraction angiography (DSA) yields high cumulative radiation dosages (RD) delivered to patients. We present a temporal interpolation of low frame rate angiograms as a method to reduce cumulative RDs. METHODS: Patients undergoing interventional evaluation and treatment of cerebrovascular vasospasm following subarachnoid hemorrhage were retrospectively identified. DSAs containing pre- and post-intervention runs capturing the full arterial, capillary, and venous phases with at least 16 frames each were selected. Frame rate reduction (FRR) of the original DSAs was performed to 50%, 66%, and 75% of the original frame rate. Missing frames were regenerated by sampling a gamma variate model (GVM) fit to the contrast response curves to the reduced data. A formal reader study was performed to assess the diagnostic accuracy of the "synthetic" studies (sDSA) compared to the original DSA. RESULTS: Thirty-eight studies met inclusion criteria (average RD 1,361.9 mGy). Seven were excluded for differing views, magnifications, or motion. GVMs fit to 50%, 66%, and 75% FRR studies demonstrated average voxel errors of 2.0 ± 2.5% (mean ± standard deviation), 6.5 ± 1.5%, and 27 ± 2%, respectively for anteroposterior projections, 2.0 ± 2.2%, 15.0 ± 3.1%, and 14.8 ± 13.0% for lateral projections, respectively. Reconstructions took 0.51 s/study. Reader studies demonstrated an average rating of 12.8 (95% CI 12.3-13.3) for 75% FRR, 12.7 (12.2-13.2) for 66% FRR and 12.0 (11.5-12.5) for 50% FRR using Subjective Image Grading Scale. Kendall's coefficient of concordance resulted in W = 0.506. CONCLUSION: FRR by 75% combined with GVM reconstruction does not compromise diagnostic quality for the assessment of cerebral vasculature. RELEVANCE STATEMENT: Using this novel algorithm, it is possible to reduce the frame rate of DSA by as much as 75%, with a proportional reduction in radiation exposure, without degrading imaging quality. KEY POINTS: • DSA delivers some of the highest doses of radiation to patients. • Frame rate reduction (FRR) was combined with bolus tracking to interpolate intermediate frames. • This technique provided a 75% FRR with preservation of diagnostic utility as graded by a formal reader study for cerebral angiography performed for the evaluation of cerebral vasospasm. • This approach can be applied to other types of angiography studies.

Case report: Transvenous coil embolization of a high-grade Galenic dural arteriovenous fistula.

Introduction: Galenic dural arteriovenous fistulas (dAVFs) are a rare form of dAVF and rarely described in the literature. Their distinct location requires different surgical approaches than dAVFs occurring at the nearby sites of the straight sinus and torcular Herophili, and their high risk of hemorrhage makes these dAVFs very challenging to approach surgically. In this report, we present a unique case of Galenic dAVF. Case description: The patient is a 54-year-old female who presented with a 2-year history of progressive headaches, cognitive decline, and papilledema. A cerebral angiogram demonstrated a complex dAVF to the vein of Galen (VoG). She underwent transarterial embolization with Onyx-18 which resulted in minimal reduction in arterial venous shunting. She subsequently underwent a successful transvenous coil embolization resulting in complete occlusion of dAVF. The patient's postoperative course was complicated by interventricular hemorrhage; however, she had a remarkable clinical recovery with resolution of headaches and improvement in cognitive function. A follow-up angiogram completed 6 months post-embolization demonstrated very mild residual shunting. Conclusion: In the unique case presented here, we demonstrate the efficacy of transvenous embolization via an occluded straight sinus as an alternative therapeutic option to eliminate cortical venous reflux.

Evolution of spinal cord injury treatment in military neurosurgery.

During the mid-1900s, military medicine made historical advancements in the diagnosis, stabilization, and treatment of spinal cord injuries (SCIs). In particular, World War II was an inflection point for clinical practice related to SCIs because of the vast number of devastating injuries to soldiers seen during World War I (WWI). The unprecedented rate of SCI along with growth in the field served as a catalyst for surgical and interdisciplinary advancements through the increased exposure to this challenging pathology. Initially, a tragic fate was assumed for soldiers with SCIs in WWI resulting in a very conservative approach strategy given a multitude of factors. However, soldiers with similar injuries 20 years later saw improved outcomes with more aggressive management interventions by specialists in spine trauma, who applied measures such as spinal traction, arthrodesis, and internal fixation, and with the significant developments in the complex rehabilitation of these patients. This article describes the historical shift in the management of SCIs through the two world wars. These historical lessons of SCI and the fundamental advances in their neurosurgical intervention have molded not only military but also modern civilian treatment of SCI.

Assessing the Impact of Early Undergraduate Exposure to the Medical School Curriculum.

BACKGROUND: Programs such as mini-medical school programs have been implemented to introduce students to the medical school curriculum through a series of lectures in foundational sciences and healthcare topics. Since 2013, the UNC School of Medicine (SOM) has offered the Introduction to Clinical Medicine for Undergraduates (ICMU) course as an opportunity for UNC undergraduate students to be introduced to the medical school curriculum and integrated into the introductory clinical skills curriculum. This study explored the relationship between experiences from taking this course, pursuit of further education in healthcare professions, and preparedness for future clinical courses. METHODS: An anonymous survey was distributed to all students who took the ICMU course at UNC-Chapel Hill as an undergraduate from 2013 to present. The locally developed survey consisted of 13 scaled questions asking about their experiences in the course and decisions to pursue further healthcare professional education. Survey results were analyzed using descriptive and correlational statistics. RESULTS: Respondents perceived the experience increased their confidence and preparedness for future clinical courses in the competency measures of taking a patient history, performing a physical examination, and developing a differential diagnosis. Inclusion of students in the clinical skills course was significantly associated with their confidence going into their health professions school of choice (p = .002). Additionally, exposure to UNC SOM students, faculty, and culture was found to play a role in students choosing to attend UNC SOM. CONCLUSION: Integration of undergraduate students into the medical school curriculum has motivated continued pursuit of education in a healthcare profession. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40670-021-01449-x.