Risk Stratification for Oropharyngeal Squamous Cell Carcinoma Using Texture Analysis on CT - A Step Beyond HPV Status.

Background and Purpose: Human papillomavirus-associated oropharyngeal squamous cell carcinoma (OPSCC) is increasingly prevalent. Despite the overall more favorable outcome, the observed heterogeneous treatment response within this patient group highlights the need for additional means to prognosticate and guide clinical decision-making. Promising prediction models using radiomics from primary OPSCC have been derived. However, no model/s using metastatic lymphadenopathy exist to allow prognostication in those instances when the primary tumor is not seen. The aim of our study was to evaluate whether radiomics using metastatic lymphadenopathy allows for the development of a useful risk assessment model comparable to the primary tumor and whether additional knowledge of the HPV status further improves its prognostic efficacy. Materials and Methods: 80 consecutive patients diagnosed with stage III-IV OPSCC between February 2009 and October 2015, known human papillomavirus status, and pre-treatment CT images were retrospectively identified. Manual segmentation of primary tumor and metastatic lymphadenopathy was performed and the extracted texture features were used to develop multivariate assessment models to prognosticate treatment response. Results: Texture analysis of either the primary or metastatic lymphadenopathy from pre-treatment enhanced CT images can be used to develop models for the stratification of treatment outcomes in OPSCC patients. AUCs range from .78 to .85 for the various OPSCC groups tested, indicating high predictive capability of the models. Conclusions: This preliminary study can form the basis multi-centre trial that may help optimize treatment and improve quality of life in patients with OPSCC in the era of personalized medicine.

Understanding Ballistic Injuries.

Understanding the pathophysiology of a disease allows physicians to make a diagnosis, alter its natural course, and develop and implement appropriate preventative and management strategies. With ballistic injuries, an understanding of how the mechanism of injury translates to the injuries observed makes it possible to make sense of what can, at times be a complex imaging appearance and mitigate against the long-term complications of gunshot wounds. In this article, the authors describe the different types of ballistic projectiles, their mechanism of injury as well as the injury patterns they cause. In addition, both lead arthropathy and MR imaging safety in patients with retained ballistic debris are discussed.

The forgotten lacrimal gland and lacrimal drainage apparatus: pictorial review of CT and MRI findings and differential diagnosis.

The lacrimal gland is a bilobed serous gland located in the superolateral aspect of the orbit. Lacrimal system pathologies can be broadly divided into pathologies of the lacrimal gland and those of the nasolacrimal drainage apparatus. These include distinct congenital, infectious, inflammatory, and benign, indeterminate, and malignant neoplastic lesions. Trauma and resultant fractures affecting lacrimal drainage apparatus is not part of this review; only non-traumatic diseases will be discussed. CT is the initial modality of choice because of its ability to delineate lacrimal system anatomy and demonstrate most lacrimal drainage system abnormalities and their extent. It also assesses bony architecture and characterizes any osseous changes. MRI is helpful in further characterizing these lesions and better assessing involvement of the surrounding soft tissue structures. In this pictorial review, we will review the anatomy of the lacrimal system, describe CT/MRI findings of the common and uncommon lacrimal system abnormalities and discuss relevance of imaging with regards to patient management.

Dual energy CT: a step ahead in brain and spine imaging.

OBJECTIVE: The purpose of this pictorial essay is to illustrate the utility of dual energy CT as an adjunct or alternative to routine single energy CT (SECT) scan of the brain and spine in emergency neuroradiology practice. CONCLUSION: Dual energy CT can be used as a problem-solving tool in brain and spine imaging. It enables one to make a confident and accurate diagnosis for a variety of clinical conditions thereby impacting patient management.

High-resolution susceptibility-weighted imaging at 3 T with a 32-channel head coil: technique and clinical applications.

OBJECTIVE: The purpose of this article is to illustrate the utility of susceptibility-weighted imaging (SWI) as an adjunct to routine MRI of the brain in neurologic disorders. CONCLUSION: SWI is a 3D spoiled gradient-echo sequence that combines phase and magnitude information to provide a high sensitivity for the detection of blood degradation products, calcifications, and iron deposits.