Standardized volumetric 3D-analysis of SPECT/CT imaging in orthopaedics: overcoming the limitations of qualitative 2D analysis

<p>Abstract</p> <p>Background</p> <p>SPECT/CT combines high resolution anatomical 3D computerized tomography (CT) and single photon emission computerized tomography (SPECT) as functional imaging, which provides 3D information about biological processes into a single imaging modality. The clinical utility of SPECT/CT imaging has been recognized in a variety of medical fields and most recently in orthopaedics; however, clinical adoption has been limited due to shortcomings of analytical tools available. Specifically, SPECT analyses are mainly qualitative due to variation in overall metabolic uptake among patients. Furthermore, most analyses are done in 2D, although rich 3D data are available. Consequently, it is difficult to quantitatively compare the position, size, and intensity of SPECT uptake regions among patients, and therefore difficult to draw meaningful clinical conclusions.</p> <p>Methods</p> <p>We propose a method for normalizing orthopaedic SPECT/CT data that enables standardised 3D volumetric quantitative measurements and comparison among patients. Our method is based on 3D localisation using clinically relevant anatomical landmarks and frames of reference, along with intensity value normalisation using clinically relevant reference regions. Using the normalised data, we describe a thresholding technique to distinguish clinically relevant hot spots from background activity.</p> <p>Results</p> <p>Using an exemplar comparison of two patients, we demonstrate how the normalised, 3D-rendered data can provide a richer source of clinical information and allow quantitative comparison of SPECT/CT measurements across patients. Specifically, we demonstrate how non-normalized SPECT/CT analysis can lead to different clinical conclusions than the normalized SPECT/CT analysis, and that normalized quantitative analysis can be a more accurate indicator of pathology.</p> <p>Conclusions</p> <p>Conventional orthopaedic frames of reference, 3D volumetric data analysis and thresholding are used to distinguish clinically relevant hot spots from background activity. Our goal is to facilitate a standardised approach to quantitative data collection and comparison of clinical studies using SPECT/CT, enabling more widespread clinical use of this powerful imaging tool.</p

Liver metastases in thyroid cancer

This book offers a complete overview on non colorectal non neuroendocrine (NCRNNE) liver metastases and describes in detail the currently available therapies. Each chapter focuses on the treatment of metastases from a particular primary malignancy and also provides valuable information on incidence, natural history and diagnosis. NCRNNE liver metastases are rare entities compared with colorectal and neuroendocrine metastases, for which the treatments are well codified. While more publications have appeared on the topic in recent years, an in-depth study has to date been lacking. Furthermore, most published series are insufficiently comparable as they comprise patients with NCRNNE hepatic metastases from a variety of primary malignancies and consequently overlook differences in tumor behavior, frequency of isolated hepatic metastases, response to neoadjuvant or adjuvant therapy and interval between diagnosis of the primary tumor and the liver metastases. This book, with its more specific approach, will serve not only as an up-to-date guide to diagnosis and treatment but also as a reference on which to base future studies.<br/