Vital Signs in Radiologic Education

Publication date: Available online 29 March 2018
Source:Academic Radiology
Author(s): Priscilla J. Slanetz




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A Feasibility Study of Single-inhalation, Single-energy Xenon-enhanced CT for High-resolution Imaging of Regional Lung Ventilation in Humans

Publication date: Available online 29 March 2018
Source:Academic Radiology
Author(s): Daniel W. Pinkham, Mohammadreza Negahdar, Tokihiro Yamamoto, Erik Mittra, Maximilian Diehn, Viswam S. Nair, Paul J. Keall, Peter G. Maxim, Billy W. Loo
Rationale and ObjectivesThe objective of this study was to assess the feasibility of single-inhalation xenon-enhanced computed tomography (XeCT) to provide clinically practical, high-resolution pulmonary ventilation imaging to clinics with access to only a single-energy computed tomography scanner, and to reduce the subject's overall exposure to xenon by utilizing a higher (70%) concentration for a much shorter time than has been employed in prior studies.Materials and MethodsWe conducted an institutional review board-approved prospective feasibility study of XeCT for 15 patients undergoing thoracic radiotherapy. For XeCT, we acquired two breath-hold single-energy computed tomography images of the entire lung with a single inhalation each of 100% oxygen and a mixture of 70% xenon and 30% oxygen, respectively. A video biofeedback system for coached patient breathing was used to achieve reproducible breath holds. We assessed the technical success of XeCT acquisition and side effects. We then used deformable image registration to align the breath-hold images with each other to accurately subtract them, producing a map of lung xenon distribution. Additionally, we acquired ventilation single-photon emission computed tomography-computed tomography (V-SPECT-CT) images for 11 of the 15 patients. For a comparative analysis, we partitioned each lung into 12 sectors, calculated the xenon concentration from the Hounsfield unit enhancement in each sector, and then correlated this with the corresponding V-SPECT-CT counts.ResultsXeCT scans were tolerated well overall, with a mild (grade 1) dizziness as the only side effect in 5 of the 15 patients. Technical failures in five patients occurred because of inaccurate breathing synchronization with xenon gas delivery, leaving seven patients analyzable for XeCT and single-photon emission computed tomography correlation. Sector-wise correlations were strong (Spearman coefficient >0.75, Pearson coefficient >0.65, P value <.002) for two patients for whom ventilation deficits were visibly pronounced in both scans. Correlations were nonsignificant for the remaining five who had more homogeneous XeCT ventilation maps, as well as strong V-SPECT-CT imaging artifacts attributable to airway deposition of the aerosolized imaging agent. Qualitatively, XeCT demonstrated higher resolution and no central airway deposition artifacts compared to V-SPECT-CT.ConclusionsIn this pilot study, single-breath XeCT ventilation imaging was generally feasible for patients undergoing thoracic radiotherapy, using an imaging protocol that is clinically practical and potentially widely available. In the future, the xenon delivery failures can be addressed by straightforward technical improvements to the patient biofeedback coaching system.



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Kite surfing: epidemiology of trauma

Kite surfing has become an increasingly popular recreational activity worldwide. Thrill seekers can span the water at high speeds and reach great heights risking injury and death. We report the case of a young kite surfer who sustained a fracture dislocation of the right acetabulum that required specialised surgical management. We present this case with a review of the literature outlining the incidence of pelvic and acetabular fractures in the kitesurfing community. Overall, there is a low incidence of pelvic fractures in comparison with other orthopaedic traumas reported among kite surfers, and the most commonly injured sites are the foot and ankle. Emergency departments should be alert to this activity and its associated injury patterns due to its ever-increasing popularity.

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Amelanotic melanoma: a unique case study and review of the literature

Amelanotic melanoma (AM) is a rare form of melanoma which lacks visible pigment. Due to the achromic manifestation of this atypical cutaneous malignancy, it has been difficult to establish clinical criteria for diagnosis. Thus, AM often progresses into an invasive disease due to delayed diagnosis. In this report, we describe the case of a 72-year-old Caucasian woman who had been diagnosed with AM after 3 years of failed treatments for what presented as a periorbital dermatitis. Her Clark's level 4, 1.30 mm thick melanoma required nine surgeries for successful resection and reconstruction. This case exemplifies the diagnostic pitfall of AM and the need for new criteria for early detection and management.

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Editorial Board

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Microanatomical Nerve Architecture of 6 Mammalian Species: Is Trans-Species Translational Anatomic Extrapolation Valid?

Background and Objectives Various animal models have historically been used to study iatrogenic nerve injury during performance of conduction nerve blocks. Our aims were to compare the microstructures of nerves in commonly used species to those of humans and to explore the validity of the extrapolating these findings to humans. Methods High-resolution, light-microscopic images were obtained from cross sections of sciatic nerves at their bifurcation from fresh rat, rabbit, pig, sheep, dog, and human cadavers. Various microanatomical characteristics were measured and compared between the species. P

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Application of precision medicine to the treatment of anaphylaxis

Purpose of review Recognize the presentation of anaphylaxis for prompt management and treatment and to provide tools for the diagnosis of the underlying cause(s) and set up a long-term treatment to prevent recurrence of anaphylaxis. Recent findings The recent description of phenotypes provides new insight and understanding into the mechanisms and causes of anaphylaxis through a better understanding of endotypes and biomarkers for broad clinical use. Summary Anaphylaxis is the most severe hypersensitivity reaction and can lead to death. Epinephrine is the first-line treatment of anaphylaxis and it is life-saving. Patients with first-line therapy-induced anaphylaxis are candidates for desensitization to increase their quality of life and life expectancy. Desensitization is a breakthrough novel treatment for patients with anaphylaxis in need of first-line therapy, including chemotherapy, mAbs, aspirin and others. Ultrarush with venom immunotherapy should be considered in patients who present with life-threatening anaphylaxis after Hymenoptera sting with evidence of IgE-mediated mechanisms. Food desensitization is currently being expanded to provide increased safety to adults and children with food-induced anaphylaxis. Correspondence to Mariana Castells, MD, PhD, Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, The Building for Transformative Medicine, 5th floor, Room 5002N, 60 Fenwood Road, Boston, MA 02115, USA. Tel: +1 617 525 1265; fax: +1 617 525 1310; e-mail: mcastells@bwh.harvard.edu Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.

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