Peter A. Harri

Variability of MDCT dose due to technologist performance: impact of posteroanterior versus anteroposterior localizer image and table height with use of automated tube current modulation.

OBJECTIVE The purpose of this study was to determine MDCT dose variability due to technologist variability in performing CT studies. MATERIALS AND METHODS Fifty consecutive adult patients who underwent two portal venous phase CT examinations of the abdomen and pelvis on the same 64-MDCT scanner between January and December 2011 were retrospectively identified. Tube voltage (kVp), tube current (mA), use of automated tube current modulation (ATCM), dose-length product (DLP), volume CT dose index (CTDIvol), table height, whether the localizer image was obtained using the posteroanterior or the anteroposterior technique, arm position, and number of overscanned slices were recorded. RESULTS For a given patient, the total examination DLP difference comparing the two MDCT studies ranged from 0.1% to 238.0%. For the same patient, total examination DLP was always higher when the localizer image was obtained with the posteroanterior compared with the anteroposterior technique. When table position was closer to the x-ray source, patients appeared magnified in the posteroanterior localizer image (8-29%; average, 14%) and higher tube currents were selected with ATCM. Localizer technique, table height, arm position, number of overscanned slices, and technologist were all significant predictors of dose. CONCLUSION Patient off-centering closer to the x-ray source resulted in patient magnification in the posteroanterior localizer image, leading to higher tube currents with ATCM and increased DLP. Differences in technologist, arm position, and overscanning also resulted in dose variability.

Posttransplantation Lymphoproliferative Disease: Proposed Imaging Classification

Posttransplantation lymphoproliferative disease (PTLD) is the second most common tumor in adult transplant recipients. Most cases of PTLD are attributed to Epstein-Barr virus. Decreased levels of immunosurveillance against this tumor virus as a result of immunosuppressive regimens are thought to account for most cases of PTLD. Histologically, PTLD ranges from relatively benign lymphoid hyperplasia to poorly differentiated lymphoma, and tissue sampling is required to establish the subtype. The frequency of PTLD varies depending on the type of allograft and immunosuppressive regimen. PTLD has a bimodal manifestation, with most cases occurring within the first year after transplantation and a second peak occurring 4-5 years after transplantation. Patients are often asymptomatic or present with nonspecific symptoms, and a mass visible at imaging may be the first clue to the diagnosis. Imaging plays an important role in identifying the presence of disease, guiding tissue sampling, and evaluating response to treatment. The appearance of PTLD at imaging can vary. It may be nodal or extranodal. Extranodal disease may involve the gastrointestinal tract, solid organs, or central nervous system. Solid organ lesions may be solitary or multiple, infiltrate beyond the organ margins, and obstruct organ outflow. Suggestive imaging findings should prompt tissue sampling, because knowledge of the PTLD subtype is imperative for appropriate treatment. Treatment options include reducing immunosuppression, chemotherapy, radiation therapy, and surgical resection of isolated lesions.

Differentiation of lipid-poor adrenal adenomas from non-adenomas with magnetic resonance imaging: Utility of dynamic, contrast enhancement and single-shot T2-weighted sequences

PURPOSE To evaluate the utility of dynamic, contrast-enhanced magnetic resonance imaging (MRI) in combination with single-shot T2-weighted (ssT2) sequences in the differentiation of lipid-poor adrenal adenomas from non-adenomas. MATERIALS AND METHODS This retrospective study was approved by the institutional review board and is HIPAA compliant. Between January 2007 and December 2010, 46 patients with MRI demonstrating a lipid-poor adrenal lesion who underwent either surgical resection or a minimum of 24 months of imaging follow-up were identified retrospectively. All images were retrospectively reviewed in blinded fashion by two radiologists. Each adrenal lesion was categorized by dynamic enhancement features and qualitative signal on ssT2 images and was categorized as an adenoma if it demonstrated homogenous enhancement in the arterial phase, washout with capsule enhancement in the delayed phase, and T2 signal isointense to normal adrenal tissue. Any lesion that did not fulfill all the criteria was classified as a non-adenoma. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for characterization of adenoma were calculated for each reader with 95% confidence intervals. A κ test assessed level of agreement between readers. RESULTS Application of our criteria lead to an MRI diagnosis of lipid-poor adrenal adenoma with a sensitivity of 84.2-89.5% (16/19-17/19), specificity of 96.3% (26/27), positive predictive value of 94.1-94.4% (16/17-17/18), negative predictive value of 89.7-92.9% (26/29-26/28), and accuracy of 91.3-93.5% (42/46-43/46). Agreement between the two readers showed substantial κ agreement for the differentiation of adenoma from non-adenoma. CONCLUSIONS Dynamic, contrast-enhanced T1-weighted three-dimensional gradient echo sequences in combination with ssT2 images can accurately differentiate lipid-poor adrenal adenomas from non-adenomas.

Protecting Your Patients’ Interests in the Era of Big Data, Artificial Intelligence, and Predictive Analytics

The Hippocratic oath and the Belmont report articulate foundational principles for how physicians interact with patients and research subjects. The increasing use of big data and artificial intelligence techniques demands a re-examination of these principles in light of the potential issues surrounding privacy, confidentiality, data ownership, informed consent, epistemology, and inequities. Patients have strong opinions about these issues. Radiologists have a fiduciary responsibility to protect the interest of their patients. As such, the community of radiology leaders, ethicists, and informaticists must have a conversation about the appropriate way to deal with these issues and help lead the way in developing capabilities in the most just, ethical manner possible.

Hematospermia Evaluation at MR Imaging.

Hematospermia is a challenging and anxiety-provoking condition that can manifest as a single episode or recur over the course of weeks to months. It is usually a benign self-limiting condition in younger sexually active males without a history of risk factors such as cancer, urogenital malformations, bleeding disorders, and their associated symptoms. However, patients with recurrent, refractory and painful hematospermia with associated symptoms, such as fever, pain, or weight loss, require evaluation through clinical assessment and noninvasive investigations to rule out underlying pathologic conditions such as ejaculatory obstruction, infectious and inflammatory causes, malignancy, vascular malformations, and systemic disorders that increase the risk of bleeding, especially when presenting in older men. If these investigations are negative, the patient should be reassured and treated accordingly. In the recent past, magnetic resonance (MR) imaging has assumed a major role in the investigation of hematospermia due to its excellent soft-tissue contrast and multiplanar capabilities. In this review, we will discuss the potential causes of hematospermia and its diagnostic workup, including pathophysiology, anatomic considerations, the imaging appearance of associated pathologic conditions, and management. (©)RSNA, 2016.

Role of imaging in the evaluation of male infertility

Infertility is defined herein as the inability to achieve pregnancy after frequently engaging in unprotected sexual intercourse for 1 year. Among infertile couples, the cause of infertility involves the male partner in approximately 50% of cases. Male infertility is usually caused by conditions affecting sperm production, sperm function, or both, or blockages that prevent the delivery of sperm. Chronic health problems, injuries, lifestyle choices, anatomic problems, hormonal imbalances, and genetic defects can have a role in male infertility. The diagnostic workup of male infertility should include a thorough medical and reproductive history, physical examination, and semen analysis, followed by imaging. The main role of imaging is identification of the causes of infertility, such as congenital anomalies and disorders that obstruct sperm transport and may be correctable. Scrotal ultrasonography is the most common initially performed noninvasive examination used to image the male reproductive system, including the testes and extratesticular structures such as the epididymis. Magnetic resonance (MR) imaging is another noninvasive imaging modality used in the pelvis to evaluate possible obstructive lesions involving the ductal system. MR imaging of the brain is extremely useful for evaluating relevant neurologic abnormalities, such as pituitary gland disorders, that are suspected on the basis of hormone analysis results. Invasive techniques are usually reserved for therapeutic interventions in patients with known abnormalities. In this article, the causes and imaging findings of obstructive and nonobstructive azoospermia are discussed. In addition to detecting treatable conditions that are related to male infertility, identifying the life-threatening entities associated with infertility and the genetic conditions that could be transmitted to offspring-especially in patients who undergo assisted reproduction-is critical. ©RSNA, 2017.

Spectrum of Extratesticular and Testicular Pathologic Conditions at Scrotal MR Imaging

Diagnostic workup of scrotal lesions should begin with a complete clinical history and physical examination, including analysis of risk factors such as family history of testicular cancer, personal history of tumor in the contralateral testis, and cryptorchidism, followed by imaging. Scrotal ultrasonography (US) with a combination of gray-scale and color Doppler techniques has been the first-line imaging modality for evaluation of testicular and extratesticular lesions because of its low cost, wide availability, and high diagnostic accuracy. However, US has limitations related to operator dependence, the relatively small field of view, and lack of tissue characterization. Magnetic resonance (MR) imaging, because of its superior soft-tissue contrast and multiplanar capabilities, is increasingly being used as a supplemental diagnostic problem-solving tool in cases where scrotal US findings are inconclusive or nondiagnostic. In addition to morphology, lesion location, and tissue characterization (eg, fat, blood products, granulation tissue, and fibrosis), scrotal MR imaging provides important information that can affect surgical planning and improve patient care. MR imaging also is helpful for differentiating testicular and extratesticular lesions, distinguishing between benign and malignant lesions, and evaluating the local extent of disease. This review discusses the anatomy and MR imaging features of testicular and extratesticular neoplastic and nonneoplastic conditions and describes relevant MR imaging techniques. ©RSNA, 2018 Contact information that appeared in the print version of this article was updated in the online version on May 14, 2018.

Magnetic Resonance Imaging of Primary Hepatic Malignancies in Patients With and Without Chronic Liver Disease: A Pictorial Review.

Primary hepatic malignancies are less common than metastatic diseases, but a recognition of these lesions is important for diagnosis and treatment planning. Magnetic resonance imaging (MRI) provides the most imaging information to diagnose lesions noninvasively and to narrow differential diagnoses. This paper reviews the imaging findings of chronic liver disease and primary hepatic malignancies, including hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (CCA), epithelioid hemangioendothelioma, hepatic angiosarcoma, and primary hepatic lymphoma. Clinical and MRI features are reviewed to improve the readers’ recognition of these tumors, allowing for a narrower differential diagnosis when liver masses are encountered on abdominal imaging.

Angiotensin Converting Enzyme (ACE) Inhibitor Associated Small BowelAngioedema and Ascites Presenting as Recurrent Acute Abdomen: A CaseReport

We describe a case of a patient who presented with recurrent abdominal pain due to small bowel angioedema believed to be caused by a recently started ACE inhibitor with classic imaging features. Very few cases of visceral angioedema due to ACE inhibitor use are described in the literature. This case demonstrates a unique direct causal association between the onset of drug administration and symptomatic bowel angioedema as well as ascites, spontaneous resolution on stopping ACE inhibitor, and recurrence of acute clinical symptoms and imaging features on resumption of the drug.

Sa2059 Ductal Dilatation As a Sign of Pancreatic Adenocarcinoma: An Analysis of 308 Pathologically-Confirmed Cases

G A A b st ra ct s for sonic hedgehog (PTCH and SMOO), GPCRs (AGTRI) and TNFaR I and II. Pancreatic mesenchymal cells were also found, using Luminex magnetic bead-based immunodetection, to be a significant source of proinflammatory cytokines IL-6 and IL-8, secreting high IL-6 levels at all times subsequent to early passages. TNF-a expression was detected only during early passage when cells exhibited an acinar-like phenotype. Interestingly, ethanol (50 mM) provided in serum free medium induced a hormetic effect, modestly stimulating cell viability associated with significant (~2-fold) elevations in HAS1, HAS2 and UGDH mRNA levels. Insulin alone (0.5-10 nM) dose-dependently suppressed HAS2 expression, but at 1 nM, modestly induced HAS1 in the presence or absence of ethanol. Ethanol-induced HAS2 gene induction was abolished in the presence of 1 nM insulin. These effects suggested some shifting between relative levels of HAS genes in response to changes in metabolic conditions. In addition, we tested the effect of conditioned medium from PDAC cell lines on HAS gene expression. The human cancer cell lines BXPC3 and MiaPaCa-2 were found to secrete high levels of IL-8, but only very low levels of IL-6 and TNF-a. Interestingly, BXPC3 and MiaPaCa2 conditioned media stimulated HAS1 and, more potently, HAS2 expression in pancreatic mesenchymal cells. We conclude that, in the tumor microenvironment, autocrine and paracrine signaling contribute to a hyaluronan synthetic phenotype that may promote tumor progression.