Neuroimaging in Dementias.

Dementia is a global health issue, the burden of which will worsen with an increasingly aging population. Alzheimer's disease (AD) is the most common dementia, with 50 to 60% of all dementias attributable to AD alone, while the rest are mostly due to frontotemporal lobar dementia, dementia with Lewy bodies, Parkinson's disease dementia, and vascular dementia. Diagnosis of dementias is made clinically with the aid of other testing modalities including neuroimaging. While the role of imaging has traditionally been to exclude reversible causes of dementia, positron emission tomography (PET) with 18-fluorine fluorodeoxyglucose and magnetic resonance imaging now are increasingly used more for definitive diagnosis of dementia in the prodromal stages and to aid with formulating the differential diagnoses. Introduction of molecular imaging modalities such as amyloid PET and tau PET have improved diagnostic certainty in the clinical trial setting and promise to find their way into the clinic in the near future. In this review, we will focus on the multimodality imaging of dementias especially AD and its differential diagnoses.

Wunderlich Syndrome: Wonder What It Is.

Wunderlich syndrome (WS) refers to spontaneous renal or perinephric hemorrhage occurring in the absence of known trauma. WS is much less common than hemorrhage occurring after iatrogenic or traumatic conditions. Lenk's triad of acute onset flank pain, flank mass, and hypovolemic shock is a classic presentation of WS but seen in less than a quarter of patients. The majority of patients present only with isolated flank pain and often imaged with an unenhanced CT in the emergency department. The underlying etiology is varied with most cases attributed to neoplasms, vascular disease, cystic renal disease and anticoagulation induced; the etiology is often occult on the initial exam and further evaluation is necessary. Urologists are familiar with this unique entity but radiologists, who are more likely to be the first to diagnose WS, may not be familiar with the imaging work up and management options. In the last decade or so, there has been a conspicuous shift in the approach to WS and thus it will be worthwhile to revisit WS in detail. In our review, we will review the multimodality imaging approach to WS, describe optimal follow up and elaborate on management.

Endoscopic Retrograde Cholangiopancreatography: Deciphering the Black and White.

Endoscopic Retrograde Cholangiopancreatography (ERCP) remains the conventional method of imaging the pancreatic and biliary tree and is performed by direct injection of iodinated contrast material via the major papilla. This diagnostic procedure gained popularity in the 1970s and subsequently paved way for ERCP guided interventions such as sphincterotomy, stone retrieval and stent placement. Currently, therapeutic ERCP is more widespread than diagnostic ERCP primarily due to the availability of noninvasive imaging. Nevertheless, more than half a million ERCPs are performed annually in the United States and radiologists need to be comfortable interpreting them. The following review will familiarize the reader with the imaging appearances of biliary and pancreatic disorders on conventional ERCP, and elaborate on therapeutic ERCP with illustrative examples.

Can a simplified CT response criteria for vascular involvement in pancreatic adenocarcinoma after neoadjuvant therapy predict survival in patients who achieved subsequent R0 resection?

PURPOSE: To investigate if a simplified image based scoring system assessing treatment response after neoadjuvant therapy (NAT) can predict survival in patients with pancreatic ductal adenocarcinoma (PDAC) who achieved subsequent R0 resection. METHODS: Retrospective analysis of 57 PDAC patients (male = 29, 51%) with mean age of 64 at diagnosis (range 42-79) who received NAT and R0 resection. Post-NAT overall, arterial and venous imaging response was characterized as improved, similar, or worse by 2 readers independently followed by consensus review. Kaplan-Meier Analysis was performed to compare overall survival (OS) with post-NAT overall imaging response. A Multivariable Cox proportional hazards analysis was performed to evaluate the association of the following variables with OS: overall, arterial and venous radiology response, clinical staging, postoperative CA19-9, and patient age. RESULTS: At study conclusion, 30/57 patients were deceased (53%), 26/57 (46%) alive, and 1 patient unknown. Post-NAT, 39/57 (68.4%) had overall improved disease and 18/57 (31.6%) had similar disease. The median OS was 55.7 months (95% CI 33.4-not reached, NR) for those with improved disease vs. 53.9 months (95% CI 14.3-NR) with similar disease (p = 0.859) after NAT. Among all clinical parameters, only post-operative CA 19-9 level was associated with OS (p = 0.002) and PFS (p = 0.005), respectively. CONCLUSION: Pancreatic cancer patients who underwent R0 resection showed no difference in survival when comparing those with similar vs improved disease on post-NAT imaging.

MRI contrast media: what clinicians need to know.

Magnetic resonance imaging (MRI) is an imaging modality that uses the differential spinning of protons (hydrogen) in the body when exposed to an external magnetic field, to produce cross-sectional images of the body. The advent of MRI is a boon to mankind as it does not involve ionizing radiation and provides superior soft tissue contrast even without administration of contrast media. The contrast media used in MRI were developed many years after MRI was already in use, the first being gadopentetate dimeglumine--a non-specific extracellular gadolinium chelate. Extracellular agents are the most widely used, although tissue-specific agents have been developed and are used as problem-solving tools in specific conditions. Tolerance to gadolinium-based contrast agents is excellent. The tissue-specific agents do have some adverse effects, though none of them are life-threatening. However, identification of a condition called nephrogenic systemic fibrosis has forced a rethink about the liberal usage of MRI contrast agents.

Curbside consults: Practices, pitfalls and legal issues.

OBJECTIVE: "Curbside consults" are informal opinions provided by one physician to another. In radiology, it often refers to opinions rendered on imaging performed at outside facilities and has evolved from being a targeted response to a discrete clinical question to a complete over-read in recent years. Given that the consults are usually sought for patients with complex conditions, the potential for error increases with informal reads, often due to the time constraint and lack of adequate information. Misinterpretations and inaccurate documentation by the referring clinician are also more likely. This study assesses the policies and views on curbside consults at academic centers in the United States. MATERIALS AND METHODS: An online survey (via SurveyMonkey.com) was circulated to the 319 active radiologist members of the Association of Program Directors. There were 80 responses, representing a 25% response rate. RESULTS: While most facilities provided second reads (92%), only a few (23%) provided written reports and read the case entirely. The majority (77%) tailored their read to answer specific clinical questions. Approximately two-thirds did not require the outside radiologist's report to be available before their interpretation. Seventy-nine percent were at least mildly concerned about liability. Up to 45% billed for the study; 39% were not aware of the billing practice. CONCLUSION: Curbside consults are widely provided at U.S. academic institutions with only a minority documenting their opinions. The majority are concerned about the legal implications and this paper puts forth recommendations to minimize the potential for errors in patient care and decrease liability.

Diagnostic imaging of posterior fossa anomalies in the fetus and neonate: part 2, Posterior fossa disorders.

This second portion of a two-part review illustrates examples of posterior fossa disorders detectable on prenatal ultrasound and MRI, with postnatal or pathology correlation where available. These disorders are discussed in the context of an anatomic classification scheme described in Part 1 of this posterior fossa anomaly review. Assessment of the size and formation of the cerebellar hemispheres and vermis is critical. Diagnoses discussed here include arachnoid cyst, Blake's pouch cyst, Dandy-Walker malformation, vermian agenesis, Joubert syndrome, rhombencephalosynapsis, Chiari II malformation, ischemia, and tumors.

Diagnostic imaging of posterior fossa anomalies in the fetus and neonate: part 1, normal anatomy and classification of anomalies.

This article is the first portion of a two-part review that illustrates the normal appearance of the cerebellum and posterior fossa on prenatal ultrasound and MRI and on postnatal diagnostic imaging studies. Classification and terminology of posterior fossa abnormalities in the literature are confusing due to evolution of concepts and sometimes lack of consensus. Accurate classification of posterior fossa anomalies is important for predicting fetal outcome and for appropriate counseling. In Part 1 of this review, prenatal and postnatal imaging techniques for assessing the posterior fossa will be discussed, followed by a discussion of how cerebellar malformations may be classified.

Brain metastasis in patients with adrenocortical carcinoma: a clinical series.

INTRODUCTION: Adrenocortical carcinoma (ACC) is a heterogeneous and rare disease. At presentation or at the time of a recurrence, the disease commonly spreads to the liver, lungs, lymph nodes, and bones. The brain has only rarely been reported as a site of metastases. OBJECTIVE: The aims of this report were to describe the clinical characteristics of patients with ACC who developed brain metastasis and were evaluated at the National Cancer Institute. METHODS: We describe the history and clinical presentation of six patients with ACC and metastatic disease in the brain. Images of the six patients and pathology slides were reviewed when available. RESULTS: The median age at the time of the diagnosis of ACC was 42 years. The median time from the initial diagnosis until the presentation of brain metastasis was 43 months. As a group the patients had previously received multiples lines of chemotherapy (median of three), and they presented with one to three metastatic brain lesions. Four patients underwent metastasectomy, one had radiosurgery, and one had both modalities. Two patients are still alive, three died, between 2 and 14 months after the diagnosis of brain metastases, and one was lost to follow-up. CONCLUSION: Patients with advanced ACC can rarely present with metastasis to the brain, most often long after the initial diagnosis. Timely diagnosis of brain metastasis with appropriate intervention after discussion in a multidisciplinary meeting can improve the prognosis in this particular scenario.

Imaging concerns unique to twin pregnancy.

The incidence of multiple gestations is increasing with rising maternal age and the utilization of artificial reproductive techniques. Twinning confers an increased risk to the pregnancy, with higher incidence of structural anomalies, preterm delivery, and perinatal morbidity and mortality. Certain conditions are unique to twin pregnancy, such as the twin-to-twin transfusion syndrome and the acardiac twin, secondary to vascular sharing between both the fetuses. Conjoined twinning is a phenomenon occurring because of late splitting of the zygote. Advances in imaging have increased our ability to manage multiple pregnancies with accurate prenatal diagnosis, better antenatal surveillance, and novel image-guided procedures. The purpose of this article is to provide an overview of the twinning process, including the pathophysiology, diagnostic pearls, and dilemmas and to briefly outline the outcomes and available treatment options to assist the radiologist in better management of multiple gestations.