The potential impact of CT-MRI matching on tumor volume delineation in advanced head and neck cancer

To study the potential impact of the combined use of CT and MRI scans on the Gross Tumor Volume (GTV) estimation and interobserver variation. Four observers outlined the GTV in six patients with advanced head and neck cancer on CT, axial MRI, and coronal or sagittal MRI. The MRI scans were subsequently matched to the CT scan. The interobserver and interscan set variation were assessed in three dimensions. The mean CT derived volume was a factor of 1.3 larger than the mean axial MRI volume. The range in volumes was larger for the CT than for the axial MRI volumes in five of the six cases. The ratio of the scan set common (i.e., the volume common to all GTVs) and the scan set encompassing volume (i.e., the smallest volume encompassing all GTVs) was closer to one in MRI (0.3-0.6) than in CT (0.1-0.5). The rest volumes (i.e., the volume defined by one observer as GTV in one data set but not in the other data set) were never zero for CT vs. MRI nor for MRI vs. CT. In two cases the craniocaudal border was poorly recognized on the axial MRI but could be delineated with a good agreement between the observers in the coronal/sagittal MRI. MRI-derived GTVs are smaller and have less interobserver variation than CT-derived GTVs. CT and MRI are complementary in delineating the GTV. A coronal or sagittal MRI adds to a better GTV definition in the craniocaudal directio

MRI in multiple myeloma : a pictorial review of diagnostic and post-treatment findings

Magnetic resonance imaging (MRI) is increasingly being used in the diagnostic work-up of patients with multiple myeloma. Since 2014, MRI findings are included in the new diagnostic criteria proposed by the International Myeloma Working Group. Patients with smouldering myeloma presenting with more than one unequivocal focal lesion in the bone marrow on MRI are considered having symptomatic myeloma requiring treatment, regardless of the presence of lytic bone lesions. However, bone marrow evaluation with MRI offers more than only morphological information regarding the detection of focal lesions in patients with MM. The overall performance of MRI is enhanced by applying dynamic contrast-enhanced MRI and diffusion weighted imaging sequences, providing additional functional information on bone marrow vascularization and cellularity. This pictorial review provides an overview of the most important imaging findings in patients with monoclonal gammopathy of undetermined significance, smouldering myeloma and multiple myeloma, by performing a 'total' MRI investigation with implications for the diagnosis, staging and response assessment. Main message aEuro cent Conventional MRI diagnoses multiple myeloma by assessing the infiltration pattern. aEuro cent Dynamic contrast-enhanced MRI diagnoses multiple myeloma by assessing vascularization and perfusion. aEuro cent Diffusion weighted imaging evaluates bone marrow composition and cellularity in multiple myeloma. aEuro cent Combined morphological and functional MRI provides optimal bone marrow assessment for staging. aEuro cent Combined morphological and functional MRI is of considerable value in treatment follow-up

Role of magnetic resonance imaging in the detection and characterization of solid pancreatic nodules: an update

Pancreatic ductal adenocarcinoma is the most common malignant tumor of the pancreas. The remaining pancreatic tumors are a diverse group of pancreatic neoplasms that comprises cystic pancreatic neoplasms, endocrine tumors and other uncommon pancreatic tumors. Due to the excellent soft tissue contrast resolution, magnetic resonance imaging (MRI) is frequently able to readily separate cystic from noncystic tumors. Cystic tumors are often easy to diagnose with MRI; however, noncystic non-adenocarcinoma tumors may show a wide spectrum of imaging features, which can potentially mimic ductal adenocarcinoma. MRI is a reliable technique for the characterization of pancreatic lesions. The implementation of novel motion-resistant pulse sequences and respiratory gating techniques, as well as the recognized benefits of MR cholangiopancreatography, make MRI a very accurate examination for the evaluation of pancreatic masses. MRI has the distinctive ability of non-invasive assessment of the pancreatic ducts, pancreatic parenchyma, neighbouring soft tissues, and vascular network in one examination. MRI can identify different characteristics of various solid pancreatic lesions, potentially allowing the differentiation of adenocarcinoma from other benign and malignant entities. In this review we describe the MRI protocols and MRI characteristics of various solid pancreatic lesions. Recognition of these characteristics may establish the right diagnosis or at least narrow the differential diagnosis, thus avoiding unnecessary tests or procedures and permitting better management