Advanced MRI Imaging Research Articles

Abstract 4232: PET imaging of galectin-3 expression with [18F]FPDTG for detection of early breast carcinoma lesions in dense breast tissue

Abstract Mammography is the gold standard for breast cancer detection with sensitivity of 85%, which decreases to 68% in women with dense breasts and to 48% in women with extremely dense breasts, making cancer detection challenging. Additional methods for breast cancer screening have been developed, including: contrast-enhanced mammography, tomosynthesis, automated whole breast ultrasound, advanced MRI and molecular imaging (99mTc-MIBI gamma camera; 18F-FDG). However, early detection and differential diagnosis of malignant vs benign breast lesions remains a major challenge in patients with dense breasts. We have been developing novel approaches to early detection and differential diagnosis of malignant vs benign breast lesions using PET imaging of galectin-3 (Gal-3), that is significantly overexpressed in breast carcinomas, as compared to pre-malignant lesions. We developed a novel radiotracer 3-[18F]fluorophenylthio-digalactoside (18F-FPTDG) with high binding affinity (Kd 14 nM) and specificity to Gal-3. In vitro radiotracer binding studies in a panel of MCF10-derived cell lines with different degrees of malignancy and Gal-3 expression, demonstrated a highly significant linear relationship between the level of Gal-3 expression and the magnitude of 18F-FPTDG binding to cell membranes (R2 = 0.99). Preliminary in vivo PET imaging studies with 18F-FPTDG in mice bearing MCF10DCIS tumor xenografts demonstrated a rapid bi-exponential clearance of 18F-FPTDG from the blood (fast and slow clearance half-times: 0.5 and 10.5 min, respectively). 18F-FPTDG cleared predominantly via the hepatobiliary route, as evidenced by high levels of radioactivity in the liver, increasing levels in duodenum and upper intestinal tract. The liver and kidney clearance followed mono-exponential kinetics with half-times of ∼120 min and 37 min, respectively. Renal clearance was more active in mice, as evidenced by higher amounts of radioactivity in the bladder. The magnitude of catabolism of [18F]FPDTG was negligible, as evidenced by very low levels of [18F]F2 accumulation in the bone at 60-75 min post injection. The level of accumulation of [18F]FPDTG-derived radioactivity in the lungs, muscles, and other organs and tissues was extremely low. Also, there was no measurable levels of [18F]FPDTG-derived radioactivity in the brain. In contrast, there were distinct regions in the breast carcinoma xenograft with higher levels of [18F]FPDTG, especially in the central regions (hypoxia). The half-time clearance of [18F]FPDTG from tumors was ∼8 min, which was about twice longer than clearance half-time from lungs and muscles - 4.5 and 4 min, respectively. Additional studies are being conducted in various breast tumor xenograft models, as well as in PyVmT transgenic mice, to assess the utility of PET/CT with [18F]FPDTG for differential diagnosis of benign vs malignant breast lesions and for biopsy guidance. Citation Format: Robin E. Bonomi, Vadim Popov, Thomas Mangner, Avraham Raz, Anthony F. Shields, Juri G. Gelovani. PET imaging of galectin-3 expression with [18F]FPDTG for detection of early breast carcinoma lesions in dense breast tissue. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4232.

Evaluating the Atrial Myopathy Underlying Atrial Fibrillation: Identifying the Arrhythmogenic and Thrombogenic Substrate.

Atrial disease or myopathy forms the substrate for atrial fibrillation (AF) and underlies the potential for atrial thrombus formation and subsequent stroke. Current diagnostic approaches in patients with AF focus on identifying clinical predictors with the evaluation of left atrial size by echocardiography serving as the sole measure specifically evaluating the atrium. Although the atrial substrate underlying AF is likely developing for years before the onset of AF, there is no current evaluation to identify the preclinical atrial myopathy. Atrial fibrosis is 1 component of the atrial substrate that has garnered recent attention based on newer MRI techniques that have been applied to visualize atrial fibrosis in humans with prognostic implications regarding the success of treatment. Advanced ECG signal processing, echocardiographic techniques, and MRI imaging of fibrosis and flow provide up-to-date approaches to evaluate the atrial myopathy underlying AF. Although thromboembolic risk is currently defined by clinical scores, their predictive value is mediocre. Evaluation of stasis via imaging and biomarkers associated with thrombogenesis may provide enhanced approaches to assess risk for stroke in patients with AF. Better delineation of the atrial myopathy that serves as the substrate for AF and thromboembolic complications might improve treatment outcomes. Furthermore, better delineation of the pathophysiologic mechanisms underlying the development of the atrial substrate for AF, particularly in its earlier stages, could help identify blood and imaging biomarkers that could be useful to assess risk for developing new-onset AF and suggest specific pathways that could be targeted for prevention.

Future directions of acute ischaemic stroke therapy

For several years, the only therapy with proven efficacy for acute ischaemic stroke was alteplase, which is approved for use within 4·5 h after stroke onset in many countries, but only within 3 h in the USA. However, the recanalisation rate with alteplase is modest. Several trials have shown substantial clinical benefit of neurothrombectomy within 6 h of ischaemic stroke onset, which has initiated a new era of acute stroke therapy. As neurothrombectomy becomes part of standard practice, additional trials will be needed to determine the best way to organise delivery of this care. Continuing clinical trials with several types of advanced MRI and CT imaging to enhance patient selection are investigating alteplase, other thrombolytic drugs, and novel endovascular devices, for use in later time periods from stroke onset. Consequently, the organisation and implementation of future clinical trials will need to adapt to what has been learned from the present generation of trials. The delivery of care to patients with acute stroke will also need to incorporate newly proven therapies, and much additional work is needed to maximise outcomes in as many patients as possible.

Imaging of tailgut cysts.

Tailgut cysts are congenital lesions that arise from the primitive hindgut in the true embryonic tail but fail to regress during gestation. These lesions are rare and more frequently encountered later in life and more commonly in women, and are the most common primary retrorectal tumor. Tailgut cysts may be asymptomatic or cause rectal bleeding, pain, or symptoms related to mass effect on the rectum or bladder. Pathologically, tailgut cysts are typically multilocular, lined with a variety of epithelial cell types, and are most frequently benign. Imaging is the linchpin of diagnosis due risks associated with biopsy. The purpose of this pictorial review is to present the spectrum of imaging findings associated with tailgut cysts on CT and MRI with focus on the use of advanced MRI and diffusion-weighted imaging. We present case examples of tailgut cysts, their CT and MR imaging findings, and diagnostic and management considerations.

Impact of Advanced MRI Imaging in Acute Stroke-Like Episodes

Impact of Advanced MRI Imaging in Acute Stroke-Like Episodes

PD2-05 IDIOPATHIC PARTIAL THROMBOSIS IS ASSOCIATED WITH CYCLING AND THE PRESENCE OF A FIBROUS WEB ON MRI

You have accessJournal of UrologySexual Function/Dysfunction/Andrology: Penis/Testis/Urethra: Benign Disease1 Apr 2015PD2-05 IDIOPATHIC PARTIAL THROMBOSIS IS ASSOCIATED WITH CYCLING AND THE PRESENCE OF A FIBROUS WEB ON MRI Emmanuel Weyne, Charlotte Schillebeeckx, Caroline Jamaer, Pieter D'hulst, Giorgio Bozzini, Richard Grunert, Piet Hoebeke, Steven Joniau, and Maarten Albersen Emmanuel WeyneEmmanuel Weyne More articles by this author , Charlotte SchillebeeckxCharlotte Schillebeeckx More articles by this author , Caroline JamaerCaroline Jamaer More articles by this author , Pieter D'hulstPieter D'hulst More articles by this author , Giorgio BozziniGiorgio Bozzini More articles by this author , Richard GrunertRichard Grunert More articles by this author , Piet HoebekePiet Hoebeke More articles by this author , Steven JoniauSteven Joniau More articles by this author , and Maarten AlbersenMaarten Albersen More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.188AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Idiopathic partial thrombosis (IPT) of the corpus cavernosum (CC) is a rare condition constituting of thrombosis of the proximal CC, causing perineal swelling and pain during erection. The aetiology is not fully understood, but in most cases a fibrous web in the crus cavernosum is found with advanced MRI imaging. In this abstract we provide an overview of 15 new IPT cases, for which 12 received conservative treatment and 3 surgical treatment. METHODS A multicentre retrospective analysis was performed to analyse presentation, diagnosis, treatment and outcome of 15 cases of IPT. RESULTS Perineal pain and swelling (13/15; 80%), unilateral (9/15; 60%) or bilateral (4/15 ; 27%), and pain during erection (9/13; 69%) were the most frequently reported symptoms in new IPT cases. Penile curvature, dysuria or fever (each 1/15 ; 7%) was uncommon. Remarkably, most patients reported being a frequent cyclist (9/15; 60%) with the episode of IPT occurring after cycling activity (7/15 ; 47%), highlighting a possible provocative factor in the onset of IPT. In all cases blood test with clotting tests (raised D-dimers (6/15; 40%)) ultrasound and MRI were performed. In all cases thrombosis and a fibrous web were seen on MRI(15/15;100%), more bilaterally (10/15;67%) than unilaterally (5/15;33%)(Fig 1). All patients were initially treated conservatively with LMWH (11/15; 73%) (prophylactic or therapeutic dose) and subsequent or simultaneous anti-aggregant therapy, resulting in resolution in most of the cases. After failure of conservative treatment, surgical incision of the web with saphenal graft repair or Heincke Miculicz reconstruction was performed in 3 cases with good functional outcome. CONCLUSIONS Cycling is often seen as a provocative factor in IPT cases. We recommend the systematic use of MRI for diagnosis of a cavernous web which is seen in almost all of IPT patients. Conservative treatment with anticoagulatory therapy provides good outcome in most of the cases. For therapy resistant cases surgery is a valuable option. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e41-e42 Peer Review Report Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Emmanuel Weyne More articles by this author Charlotte Schillebeeckx More articles by this author Caroline Jamaer More articles by this author Pieter D'hulst More articles by this author Giorgio Bozzini More articles by this author Richard Grunert More articles by this author Piet Hoebeke More articles by this author Steven Joniau More articles by this author Maarten Albersen More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

A20 Session 6: Case studies in ablative therapy : Robotic acoustic ablation with HIFU: Technology and clinical outcomes

High Intensity Focused Ultrasound (HIFU) is a minimally invasive technology that produces thermal ablation of soft tissues. HIFU has been employed to treat prostate cancer and transrectal prostate HIFU devices have been in use worldwide since the mid 1990s. Prostate HIFU is not FDA approved in the United States; however, two manufacturers have HIFU devices currently under evaluation in the United States by the FDA. Prostate HIFU has been used to treat primary and radiation recurrent prostate cancer. In this presentation, the Sonablate (Sonacare Medical) and Ablatherm (EDAP) prostate HIFU devices will be compared. Published clinical outcomes for primary and salvage total and partial gland HIFU ablation will be presented. Long term studies document good clinical efficacy with biochemical recurrence, overall survival, and metastasis free survival similar to standard prostate cancer treatments. The advantages of HIFU ablation are similar to other ablation technologies: HIFU is an outpatient, minimally invasive treatment with low rates of ED and incontinence and can be repeated if there is local recurrence. Focal treatment with HIFU is a promising treatment strategy and the use of advanced MRI imaging to diagnose prostate cancer and to direct HIFU ablation will be presented. High patient demand for minimally invasive prostate cancer ablative treatments will inspire urologists interested in thermal ablation to obtain training and achieve competence in prostate HIFU therapy.

Epilepsy surgery in MRI-negative epilepsies

This study discusses the challenges of MRI-negative epilepsy surgery, and the strategies in using advanced MRI and functional imaging tests and their associated postsurgical outcome. Several methods for processing MRI postacquisition data have identified either previously undetectable or overlooked MRI abnormalities. The resection of these abnormalities is associated with excellent postsurgical seizure control. There have been major advances in functional imaging as well, one of which is the application of statistical parametric mapping analysis for comparing patient data against normative data. This approach has specifically improved the usefulness of both PET and single-photon emission computed tomography in MRI-negative epilepsy surgery evaluation. One other development of importance is that of PET-MRI coregistration, which has recently been shown to be superior to conventional PET. More recent publications on magnetoencephalography have added to the literature of its use in MRI-negative epilepsy surgery evaluation, which up to now remains somewhat limited. However, recent data now indicate that single magnetoencephalography cluster is associated with better chance of concordance with intracranial EEG localization, and with excellent postsurgical seizure control if completely resected. Advanced MRI and functional imaging and subsequent intracranial EEG confirmation of the seizure-onset zone are essential to make MRI-negative epilepsy surgery possible and worthwhile for the patient.

Artifact quantification and tractography from 3T MRI after placement of aneurysm clips in subarachnoid hemorrhage patients

BackgroundThe application of advanced 3T MRI imaging techniques to study recovery after subarachnoid hemorrhage (SAH) is complicated by the presence of image artifacts produced by implanted aneurysm clips. To characterize the effect of these artifacts on image quality, we sought to: 1) quantify extent of image artifact in SAH patients with implanted aneurysm clips across a range of MR sequences typically used in studies of volumetry, blood oxygen level dependent signal change (BOLD-fMRI), and diffusion-weighted imaging (DW-MRI) and 2) to explore the ability to reconstruct white matter pathways in these patients.MethodsT1- and T2-weighted structural, BOLD-fMRI, and DW-MRI scans were acquired at 3T in two patients with titanium alloy clips in ACOM and left ACA respectively. Intensity-based planimetric contouring was performed on aligned image volumes to define each artifact. Artifact volumes were quantified by artifact/clip length and artifact/brain volume ratios and analyzed by two-way (scan-by-rater) ANOVAs. Tractography pathways were reconstructed from DW-MRI at varying distances from the artifacts using deterministic methods.ResultsArtifact volume varied by MR sequence for length (p = 0.007) and volume (p < 0.001) ratios: it was smallest for structural images, larger for DW-MRI acquisitions, and largest on fMRI images. Inter-rater reliability was high (r = 0.9626, p < 0.0001), and reconstruction of white matter connectivity characteristics increased with distance from the artifact border. In both patients, reconstructed white matter pathways of the uncinate fasciculus and inferior fronto-occipital fasciculus were clearly visible within 2 mm of the artifact border.ConclusionsAdvanced 3T MR can successfully image brain tissue around implanted titanium aneurysm clips at different spatial ranges depending on sequence type. White matter pathways near clip artifacts can be reconstructed and visualized. These findings provide a reference for designing functional and structural neuroimaging studies of recovery in aSAH patients after clip placement.

Pseudoprogression: Relevance With Respect to Treatment of High-Grade Gliomas

The post-treatment imaging assessment of high-grade gliomas remains challenging notwithstanding the increased utilization of advanced MRI and PET imaging. Several post-treatment imaging entities are recognized including: late-delayed radiation injury, including radionecrosis mimicking tumor progression; early-delayed (within 6 months of temozolomide-based chemoradiation) post-treatment radiographic changes, herein referred to as pseudoprogression (the subject of this review); early post-treatment changes following local glioma therapy (i.e. biodegradable BCNU wafer implantation or stereotactic radiotherapy); and pseudoresponse, seen following treatment with angiogenic inhibition based therapy such as bevacizumab. A literature review searched specifically for "pseudoprogression" within the last 5 years (2005-2010). Approximately 24 recent papers were identified and reviewed in detail. Eight small population-based studies demonstrate 26-58% (median 49%) of glioblastoma patients treated with chemoradiotherapy manifest early disease progression at first post-radiotherapy imaging. Patients with early radiographic disease progression continued on planned therapy, and a median of 38% (range 28-66%) showed radiographic improvement or stabilization and were defined retrospectively as manifesting pseudoprogression. In conclusion, pseudoprogression is a frequent early post-treatment imaging change that at present is not easily differentiated from tumor progression by anatomic or physiologic brain imaging. Consequently, an operational definition of pseudoprogression has been adopted by the Response Assessment in Neuro-Oncology Working Group wherein either the index (i.e. target) lesion stabilizes or diminishes in size on continued post-radiation (temozolomide) therapy as determined by follow-up radiologic imaging.

Molecular Imaging in Oncology.

Molecular Imaging in Oncology. Pomper Martin G. and Gelovani Juri G. Informa Healthcare USA, Inc., 2008. Hardcover 744 pp. Price: $399.95. ISBN 9780849374173.