Kevin O’Regan

Uterine Sarcomas: Then and Now

OBJECTIVE The purpose of this article is to provide an updated review of uterine sarcomas. The traditionally described neoplasms are reviewed as well as several recently characterized entities in terms of their imaging and clinical aspects. We attempt to provide a longitudinal imaging overview, from initial presentation to follow-up. Imaging features are also described of response to traditional therapeutic agents and newer targeted agents. CONCLUSION A greater understanding of the pathogenesis has improved our ability to image and treat uterine sarcomas, both at initial staging and on follow-up. Targeted therapy is assuming an increasingly important role in the management of these lesions. It is imperative for radiologists to be aware of response characteristics and potential complications of these agents as well as conventional chemotherapeutic agents.

Thromboprophylaxis using a low molecular weight heparin delays fracture repair.

Low molecular weight heparins are significantly superior to unfractionated heparin or warfarin in the prevention of thromboembolic episodes associated with orthopaedic surgery. Therapeutic doses of heparin and warfarin have been shown to delay bone repair in a rabbit model. The current study investigated the effect of prophylactic administration of a low molecular weight heparin, enoxaparin, on the healing of a closed rabbit rib fracture. Fracture healing was assessed using histomorphometric, histologic, and immunohistochemical methods at 3, 7, and 14 days, and biomechanical testing with torsional loading was assessed after 21 days. Bone repair was significantly attenuated at all times in animals receiving subcutaneous enoxaparin compared with that of the control animals. Numerous putative mechanisms for this phenomenon are discussed, and additional studies are proposed to elucidate the effects of this pharmacologically diverse group of compounds on all aspects of bone physiology and repair.

A to Z of Extraskeletal Ewing Sarcoma Family of Tumors in Adults: Imaging Features of Primary Disease, Metastatic Patterns, and Treatment Responses

OBJECTIVE Though classically thought of as an osseous-based sarcoma of children and adolescents, it is important to recognize that approximately 20% of all cases of Ewing sarcoma family of tumors (ESFT) occur in patients older than 18 years, often with extraskeletal disease. Understanding the specific imaging features, manners of presentation, and patterns of behavior of ESFT is therefore important in all settings. CONCLUSION This article presents the imaging findings of ESFT in the adult, with specific attention to extraskeletal manifestations.

Decade of molecular targeted therapy: abdominal manifestations of drug toxicities--what radiologists should know.

OBJECTIVE Novel drugs targeting molecular pathways involved in tumor development have revolutionized cancer treatment. Radiologists often focus on therapeutic response when evaluating cancer patients and may miss important signs of drug toxicity. This article familiarizes radiologists with the complications of molecular targeted agents in abdominal solid organs, enabling early identification and appropriate intervention and thus reducing patient morbidity and mortality. CONCLUSION Knowledge of the common abdominal toxicities--including hepatitis, cholecystitis, pancreatitis, fluid retention, and infection--is crucial for early diagnosis, which may spare patients devastating complications or the need for surgery.

PRES (posterior reversible encephalopathy syndrome), a rare complication of tacrolimus therapy

With increasing numbers of solid organ and hematopoietic stem cell transplantations being performed, there have been significant increases in the use of immunosuppressive agents such as cyclosporine and tacrolimus. Posterior reversible encephalopathy syndrome (PRES) is a serious complication of immunosuppressive therapy use following solid organ or stem cell transplants. Clinical findings including headache, mental status changes, focal neurological deficits, and/or visual disturbances. Associated with these are characteristic imaging features of subcortical white matter lesions on computed tomography (CT) or magnetic resonance imaging (MRI). The changes in the subcortical white matter are secondary to potentially reversible vasogenic edema, although conversion to irreversible cytotoxic edema has been described. These imaging findings predominate in the territory of the posterior cerebral artery. Many studies have shown that the neurotoxicity associated with tacrolimus may occur at therapeutic levels. In most cases of PRES, the symptom complex is reversible by reducing the dosage or withholding the drug for a few days. While PRES is an uncommon complication, it is associated with significant morbidity and mortality if it is not expeditiously recognized. MRI represents the most sensitive imaging technique for recognizing PRES. This report highlights the value of MRI in prompt recognition of this entity, which offers the best chance of avoiding long-term sequelae.

An assessment of medical students’ awareness of radiation exposures associated with diagnostic imaging investigations

ObjectivesThis study assessed students’ awareness of radiation exposures and determined the impact a curriculum in clinical radiology (CICR) had on awareness.MethodsSix hundred seventy medical students at one medical school were studied. CICR was delivered in yearly modules over the 5-year programme. Five hundred twenty-three students (years 1–5), exposed to increasing numbers of CICR modules and 147 students beginning medical school (year 0), represented the study and control groups, respectively. Students completed a multiple choice questionnaire assessing radiation knowledge and radiology teaching.ResultsMost students in the study population received CICR but 87% considered they had not received radiation protection instruction. The percentage of correctly answered questions was significantly higher in the study population than the control group (59.7% versus 38%, p < 0.001). Students who received CICR achieved higher scores than those who did not (61.3% compared with 42.8%, p < 0.001). Increasing exposure to CICR with each year of medical education was associated with improved performance.ConclusionsAssessment of students’ awareness of radiation exposures in diagnostic imaging demonstrates improved performance with increasing years in medical school and/or increasing exposure to CICR. Findings support the Euroatom 97 directive position, advocating implementation of radiation protection instruction into the undergraduate medical curriculum.

Pheochromocytoma and paraganglioma: imaging characteristics

Abstract The accurate diagnosis of adult pheochromocytoma and paraganglioma necessitates a multidisciplinary approach that includes clinical history, biochemical testing, and multimodality imaging such as computed tomography, magnetic resonance imaging, and nuclear medicine studies. This review illustrates the different imaging characteristics of primary adult pheochromocytomas as well as both sympathetic and parasympathetic paragangliomas. The review also describes known genetic associations and shows common metastatic patterns. Knowledge of the diverse appearance of pheochromocytomas and paragangliomas can result in early initial diagnosis or detection of disease recurrence thereby affecting patient management and prognosis.

Extrahepatic spread of hepatocellular carcinoma: spectrum of imaging findings.

OBJECTIVE The purpose of this article is to describe the imaging findings of extrahepatic spread of hepatocellular carcinoma (HCC). CONCLUSION Detecting extrahepatic metastases in HCC is critical in determining the optimal treatment plan for patients. Identifying the presence of extrahepatic metastases in patients with advanced disease may eliminate unnecessary surgery, such as liver transplantation or partial hepatic resection, and help direct the appropriate therapy.

PET/CT and Renal Pathology: A Blind Spot for Radiologists? Part 1, Primary Pathology

OBJECTIVE PET/CT with (18)F-FDG shows metabolically active disease and is widely used for the diagnosis and follow-up of patients with cancer. Nonmetabolically active renal pathology may be missed without close attention to the CT portion of the study, whereas metabolically active pathology may be missed on PET because of physiologic tracer excretion in the kidneys. This article illustrates primary lesions of the kidney on FDG PET/CT with emphasis on key anatomic features and the appearance of tracer uptake. CONCLUSION Close attention to both the FDG PET and CT portions of the study is essential to interpret renal pathology correctly on FDG PET/CT examinations.

PET/CT and Renal Pathology: A Blind Spot for Radiologists? Part 2???Lymphoma, Leukemia, and Metastatic Disease

OBJECTIVE PET/CT with (18)F-FDG is a powerful tool to evaluate patients with hematologic malignancy or to assess the burden of metastatic disease from solid tumors. Metabolically active renal pathology associated with lymphoma, leukemia, or metastatic disease can be missed without close attention to both the PET and CT portions of the study because of physiologic FDG excretion in the kidneys. This article illustrates the appearance of tracer uptake and the key anatomic features of lymphoma, leukemia, and metastatic disease involving the kidney on FDG PET/CT. CONCLUSION Close attention to both the FDG PET and CT portions of an FDG PET/CT study is essential to evaluate the kidneys in oncology patients.