Ciaran Johnston

Use of Provocative Angiography to Localize Site in Recurrent Gastrointestinal Bleeding

BackgroundWhile the source of most cases of lower gastrointestinal bleeding may be diagnosed with modern radiological and endoscopic techniques, approximately 5% of patients remain who have negative endoscopic and radiological investigations [1].Clinical ProblemThese patients require repeated hospital admissions and blood transfusions, and may proceed to exploratory laparotomy and intraoperative endoscopy. The personal and financial costs are significant.Method of Diagnosis and Decision MakingThe technique of adding pharmacologic agents (anticoagulants, vasodilators, fibrinolytics) during standard angiographic protocols to induce a prohemorrhagic state is termed provocative angiography. It is best employed when significant bleeding would otherwise necessitate emergency surgery.TreatmentThis practice frequently identifies a bleeding source (reported success rates range from 29 to 80%), which may then be treated at the same session. We report the case of a patient with chronic lower gastrointestinal hemorrhage with consistently negative endoscopic and radiological workup, who had an occult source of bleeding identified only after a provocative angiographic protocol was instituted, and who underwent succeeding therapeutic coil embolization of the bleeding vessel.

CT and PET/CT findings of T-cell lymphoma.

OBJECTIVE The purpose of this study was to describe the extranodal features of T-cell lymphoma at CT and PET/CT. CONCLUSION The extranodal features of T-cell lymphoma are not specific and usually cannot be used to differentiate T-cell lymphoma from other aggressive types of lymphoma. Noncutaneous subtypes frequently manifest with visceral involvement. The goal of CT in initial staging is to exclude visceral involvement. Evidence on the utility of PET/CT is promising, showing high diagnostic value in evaluation of occult disease and treatment response, but the role of PET/CT is evolving.

Evaluation of low-density neutral oral contrast material in PET/CT for tumor imaging: results of a randomized clinical trial.

OBJECTIVE The objective of this study was to determine the impact on image quality and risks in terms of artifacts and side effects of a low-density barium-based suspension as oral contrast material for CT during PET/CT examinations of an oncologic patient population. SUBJECTS AND METHODS Eighty-five patients (51 men and 34 women; mean age, 53 years; age range, 21-87 years) were prospectively randomized to receive either 0.1% barium sulfate oral suspension or no oral contrast material during PET/CT. Patients in the oral contrast group were given 1,350 mL over 60-75 minutes. The (18)F-FDG PET component of each examination was reviewed for the presence of artifacts by two nuclear medicine physicians and was classified as adequate (no presence of artifactual focal FDG uptake attributed to attenuation-correction errors) or inadequate (focal uptake in attenuation-correction PET images with no corresponding uptake in non-attenuation-corrected PET images). Two radiologists reviewed the CT studies and scored the degree of bowel opacification using a 5-point scale, ranging from 0 for no opacification (i.e., not possible to delineate the bowel structures from the surrounding tissues) to 4 for excellent opacification (i.e., bowel structure identifiable and bowel wall clearly visible). The attenuation values (in Hounsfield units) were recorded in the stomach, duodenum, mid jejunum, and terminal ileum for quantitative analysis. Interobserver variability was assessed using kappa coefficients. RESULTS None of the patients who received oral contrast material experienced side effects. All 85 PET examinations were considered adequate with no observable artifacts. The mean bowel opacification scores of the oral contrast group (2.59 and 2.93) as evaluated by radiologists 1 and 2, respectively, were significantly higher (p < 0.01) than those of the control group (1.55 and 1.59). The level of attenuation achieved in the contrast group was significantly higher than in the control group. The interobserver variability was moderate (kappa = 0.32). CONCLUSION The use of low-density neutral oral contrast material for CT during combined FDG PET/CT studies significantly improves visualization of the bowel structures compared with no contrast material without causing side effects or clinically detectable errors in the attenuation correction of the FDG PET study.

New targeted molecular therapies for cancer: radiological response in intrathoracic malignancies and cardiopulmonary toxicity: what the radiologist needs to know

The emergence of new novel therapeutic agents which directly target molecules that are uniquely or abnormally expressed in cancer cells (molecular targeted therapy, MTT) has changed dramatically the treatment of cancer in recent years. The clinical benefit associated with these agents is typically limited to a subset of treated patients, who in many cases are defined by a specific genomic mutations and expression lesion within their tumor cells. All these new therapy modalities represent new challenges to radiologists as their mechanism of action and side effect profiles differ from conventional chemotherapy agents. In this article we will discuss radiological patterns of response to molecular targeted therapies MTT in lung cancer, typical and atypical radiological responses of targeted molecular therapy for other intra thoracic malignancies, cardiopulmonary toxicity and other side effects of molecular targeted therapy MTT in the thorax.

Melanoma metastático causando intussuscepção do intestino delgado: diagnóstico por 18F-FDG PET/TC

Malignant melanoma is a common and aggressive disease that frequently causes metastases to the small bowel. This study illustrates a case of small bowel intussusception secondary to metastatic melanoma visualized at 18F-FDG PET/CT in a 48-year-old woman who had this examination for restaging purposes.

Your Patient Has Symptomatic Fibroids and Would Like to Have a Baby: What Treatment Should You Advise?

A 30-year-old woman with irregular menses is planning a pregnancy. Ultrasound shows a 6-cm intramural fibroid. She asks whether myomectomy or uterine artery embolization (UAE) is the treatment of choice. Friends of hers have had UAE, and she has looked at the Society of Interventional Radiology (SIR) Web site. What would you advise? Many women present in this fashion to general practitioners or gynaecologists or directly to interventional radiologists. Expert opinions differ. The SIR states that there have been numerous reports of pregnancies after UAE. The British Society of Interventional Radiology [1] is more cautious and states that there is insufficient data at this time to ensure that UAE is safe for women who may wish to become pregnant in the future, because few studies have assessed the effect of embolization on pregnancy-related outcomes. As radiologists, we wanted to establish the best current evidence. The McMaster/Oxford ‘‘bottom-up’’ evidence based practice methodology was applied to this question. Initially, a focused clinical question or Patient Population, Intervention, Comparison, Outcomes (PICO) question was designed, as previously described by Staunton [2]: ‘‘In women with symptomatic fibroids desiring future fertility, is uterine artery embolization or myomectomy associated with superior reproductive results?’’

Imaging Tools in Human Research

Publisher Summary Imaging is useful to direct procedures, guide treatments, monitor known disease and assess response to therapy. This chapter reviews the scope of imaging modalities available to the clinical investigator engaged in accelerating the translation of basic discoveries into improved therapies and clinical practice. Computed tomography (CT) technology have dramatically increased the data acquisition speed of CT imaging, and multi-detector row CT systems can acquire detailed imaging data for large regions of the body in only a few seconds. This rapid acquisition makes it possible to generate three-dimensional images of rapidly moving structures. Further, magnetic resonance imaging (MRI) is a well-established medical imaging technology with proven outcomes in both clinical medicine and biomedical research. The major strength of MRI is that it can provide an excellent contrast definition of normal anatomy and pathologic processes. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are powerful technologies capable of imaging biochemical processes in vivo in real-time by depicting low-density target proteins with a small dose of radionuclide-labeled probe. Optical imaging uses fluorescent and bioluminescent probes that emit radiation at visible or near-infrared wavelengths, which can be detected by optical cameras. Regarding the use of X-rays, two imaging approaches are available: planar-projection approaches, such as standard radiography and fluoroscopy; and cross-sectional approaches, namely CT.