Bindu N. Setty

Heme induces endothelial tissue factor expression: potential role in hemostatic activation in patients with hemolytic anemia

Summary.  Objectives: We explored the possibility that heme, an inflammatory mediator and a product of intravascular hemolysis in patients with hemolytic anemia including sickle cell disease, could modulate hemostasis by an effect on endothelial tissue factor (TF) expression. Methods: Levels of TF mRNA, protein and procoagulant activity were measured in heme‐treated endothelial cells. Results: Heme induces TF expression on the surface of both macrovascular and microvascular endothelial cells in a concentration‐dependent manner, with 12‐fold to 50‐fold induction being noted (enzyme‐linked immunosorbent assay) between 1 and 100 μm heme (P < 0.05). Complementary flow cytometry studies showed that the heme‐mediated endothelial TF expression was quantitatively similar to that of tumor necrosis factor‐alpha (TNF‐α). Heme also upregulated the expression of TF mRNA (8‐fold to 26‐fold), protein (20‐fold to 39‐fold) and procoagulant activity (5‐fold to 13‐fold) in endothelial cells in a time‐dependent manner. The time‐course of heme‐mediated TF antigen expression paralleled the induction of procoagulant activity, with antibody blocking studies demonstrating specificity for TF protein. Interleukin (IL)‐1α, and TNF‐α are not involved in mediating the heme effect, as antibodies against these cytokines and IL‐1‐receptor antagonist failed to block heme‐induced TF expression. Inhibition of heme‐induced TF mRNA expression by sulfasalazine and curcumin suggested that the transcription factor nuclear factor kappaB is involved in mediating heme‐induced TF expression in endothelial cells. Conclusions: Our results demonstrate that heme induces TF expression by directly activating endothelial cells, and that heme‐induced endothelial TF expression may provide a pathophysiologic link between the intravascular hemolytic milieu and the hemostatic perturbations previously noted in patients with hemolytic anemia including sickle cell disease.

Acute chest syndrome of sickle cell disease: new light on an old problem

The pulmonary findings of acute chest syndrome of sickle cell disease have been well characterized in numerous studies. Whereas a third of patients have a documented infection associated with this syndrome, and fat embolism from necrotic marrow is the etiologic factor in another approximately 10%, no cause is discovered in the majority of patients. In most patients, however, the underlying pathophysiology is the presence of a hypoxia-driven, adhesion-related occlusive event in the pulmonary microcirculation. This may be accompanied by a decrease in the levels of normal cytoprotective and anti-adhesive mediators such as nitric oxide. In the patient with sickle cell disease, the lung is also a uniquely vulnerable target organ because its vasculature constricts with hypoxia in contrast to other vascular beds. This review will establish the links between known etiologic agents and the pathophysiology of this syndrome. An additional section of this review will deal with experimental therapies. The use of inhaled nitric oxide will be explored in depth because advances in this area are current and uniquely relevant to acute chest syndrome.

Liver Lesion Detection and Characterization in Patients With Colorectal Cancer : A Comparison of Low Radiation Dose Non-enhanced PET/CT, Contrast-enhanced PET/CT, and Liver MRI

Objectives: To compare low-radiation dose nonenhanced fluorine 18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET)/computed tomography (CT) (NE-PET/CT), contrast-enhanced fluorine 18 fluorodeoxyglucose PET/CT (CE-PET/CT), and gadolinium-enhanced liver magnetic resonance imaging (MRI) for the detection and characterization of liver lesions in patients with colorectal cancer (CRC). Methods: In this retrospective review of imaging database of CRC patients with suspected liver metastases, 33 patients (22 men, 11 women; mean age, 63 years) evaluated with low-radiation dose NE-PET/CT, CE-PET/CT, and liver MRI were studied. The final diagnosis was established either by pathological examination or follow-up imaging over a period of at least 6 months for lesion stability or growth. The liver lesions were characterized on an ordinal scale of 0 to 6 (0 = absent, 1 = definitely benign, and 6 = definitely malignant). Receiver operating characteristic analysis was performed to compare performance of the 3 imaging methods. Results: A total of 110 lesions were present on follow-up. The detection rate on low-radiation dose NE-PET/CT, CE-PET/CT, and MRI was 73.6%, 90.9%, and 95.4%, respectively. Magnetic resonance imaging (P < 0.001) and CE-PET/CT (P < 0.001) had a higher detection rate than low-radiation dose NE-PET/CT. There was no significant statistical difference in lesion detection between MRI and CE-PET/CT (P = 0.11). The sensitivity, specificity, and accuracy for characterization of detected liver lesions on low-radiation dose NE-PET/CT were 67%, 60%, and 66%, respectively; those on CE-PET/CT were 85%, 100%, and 86%, respectively; and those on MRI were 98%, 100%, and 98%, respectively. Comparative receiver operating characteristic analysis showed an area under curve of 0.74 for low-radiation dose NE-PET/CT, 0.86 for CE-PET/CT, and 0.97 for MRI. There were statistically significant differences in the accuracy of MRI, low-radiation dose NE-PET/CT, and CE-PET/CT for lesion characterization. Conclusions When performing PET/CT, optimal detection and characterization of liver lesions require the use of a fused contrast-enhanced CT. Magnetic resonance imaging and CE-PET/CT have similar lesion detection rates. Magnetic resonance imaging is the best test for liver lesion characterization in patients with CRC.

Comparison of enhancement, image quality, cost, and adverse reactions using 2 different contrast medium concentrations for routine chest CT on 16-slice MDCT.

Objective: To evaluate the degree of enhancement and image quality of chest computed tomographic (CT) examinations on 16-slice multidetector CT using low-concentration [300 milligrams of iodine per milliliter (mg I/mL)] and high-concentration (370 mg I/mL) contrast media; to assess the impact on cost and adverse reactions of the use of high-iodine concentration contrast medium. Materials and Methods: A total of 100 patients scheduled for routine chest CT examinations were administered nonionic contrast medium of 2 strengths: low-iodine concentration contrast medium (300 mg I/mL) [group A: n = 50; male-female ratio, 28:22; mean age, 58.4 years] and high-iodine concentration contrast medium (370 mg I/mL) (group B: n = 50; male-female ratio, 18:32; mean age, 57.6 years) with a constant amount of iodine (400 mg) injected per kilogram of body weight. Contrast media were injected using a dual injector at 2.5 mL/s followed by a 30-mL saline at 2.5 mL/s. The degree of enhancement was quantified by measuring Hounsfield unit values in different arteries and veins and was also rated on a 5-point scale for qualitative assessment. We also evaluated perivenous contrast-related artifacts. The data were compared using Mann-Whitney U test for both qualitative and quantitative enhancement ratings. A P value of less than 0.05 was considered statistically significant. The P value was adjusted using Bonferroni correction for statistical significance when multiple comparisons were performed. The difference in cost and the incidence of adverse reactions in both groups were calculated. Results: The mean enhancement values in group B were significantly greater (P < 0.05) than those in group A. The mean Hounsfield units and standard deviation in groups A and B were aorta = 153 ± 4, 216 ± 20; pulmonary artery = 147 ± 10, 208 ± 20; superior vena cava = 155 ± 27, 299 ± 72; and pulmonary vein = 134 ± 10, 215 ± 30, respectively. The mean enhancement on a 5-point scale was greater in group B (4.2) than in group A (3.3) (P < 0.01). No significant difference between groups in perivenous artifacts was seen. Up to 5.5% savings in cost resulted from the use of a higher concentration of iodine, with no increase in adverse reactions. Conclusions: Use of higher-concentration contrast media provides a higher degree of contrast enhancement and image quality for a routine chest CT on a 16-slice multidetector CT. It also contributes to considerable cost savings with no increased risk of adverse reactions compared with low-concentration contrast media.

Sonography of the Pediatric Scrotum: Emphasis on the Ts—Torsion, Trauma, and Tumors

OBJECTIVE The purpose of this article is to review the different scrotal disease entities in the pediatric population, focusing on acute scrotum, traumatic injuries, and testicular tumors. CONCLUSION Many pediatric scrotal disorders can be well characterized on sonography. An understanding of the various disease entities, their clinical presentations, and the typical sonographic features should all be combined to make an accurate diagnosis.

Multiple-Detector Computed Tomographic Angiography of Pancreatic Neoplasm for Presurgical Planning : Comparison of Low-and High-Concentration Nonionic Contrast Media

Objective: To evaluate the degree of contrast enhancement, image quality, and accuracy of predicting resectability of pancreatic neoplasm with 16-row multiple-detector computed tomography (MDCT) angiography using low- and high-concentration (300 and 370 mg of iodine per milliliter, respectively) contrast media (CMs). Materials and Methods: Forty patients who had undergone pancreatic CT angiography (CTA) on 16-MDCT scanner and had surgery were included. Contrast medium of 2 iodine concentrations (group A, 300 mg/mL, n = 20; group B, 370 mg/mL, n = 20) from the same vendor (Isovue; Bracco Diagnostics), with iodine dose of 550 to 600 mg/kg of body weight, was injected at a rate of 5 mL/s. Dual-phase 16-row MDCT was performed using 1.25- and 5-mm collimation for the arterial and portal phases, respectively. For the quantitative analysis, Hounsfield units values in the aorta, superior mesenteric artery, portal vein, and pancreas during arterial and venous phases were measured. Two readers subjectively rated the overall image enhancement, 3-dimensional image quality, and lesion and pancreatic duct conspicuity. Accuracy of lesion resectability was also established for each patient. The data were compared using Student t test for statistical analysis. Results: The quantitative analysis for the degree of enhancement (Hounsfield unit) of the aorta, superior mesenteric artery, and pancreas during the arterial phase demonstrated similar values in groups A (low-concentration CM) and B (high-concentration CM), with no statistically significant difference with each other (P > 0.05). During the portal venous phase, we found superior enhancements in the superior mesenteric and portal veins in group A (P < 0.05). The qualitative assessments of the overall image enhancement and 3-dimensional image quality on a 5-point scale were 4.3 and 4.65, respectively (P < 0.05), in group A and 4.6 and 4.75, respectively, in group B, whereas on a 3-point scale, the pancreatic duct display and lesion conspicuity were 2.75 and 2.85, respectively, in group A and 2.9 and 2.9, respectively, in group B. The accuracy for lesion resectability was 95% (19/20) in group A and 100% (20/20) in group B (P > 0.05). Conclusion: Both CMs demonstrated comparable performance for 16-row MDCT of the pancreas for presurgical planning. However, high-concentration CM (370 mg of iodine per milliliter) provides higher overall enhancement and superior-quality 3-dimensional images with a shorter injection duration.

Expected Sonographic Appearance of the Spleen in Children and Young Adults With Sickle Cell Disease An Update

: To update the imaging literature regarding spleen appearances in young patients with sickle cell disease (SCD).

Beyond B-Cell Lymphomas: A Case of Optic Nerve Anaplastic Large Cell Lymphoma in a HIV Positive Patient

The immunocompromised population is known to be at greater risk for developing primary central nervous system lymphoma (pCnsL) mostly of B-cell origin [2, 9]. There is evidence showing an increased risk of T-cell lymphoma in the human immunodeficiency virus (HIV) positive population [1, 9]. primary central nervous system anaplastic large cell lymphoma (pCns-ALCL), a T-cell lymphoma, is exceedingly rare and the reported cases have demonstrated an aggressive and fatal course [4]. To our knowledge, there is no reported case of pCns-ALCL arising from the optic nerve, specifically in the HIV-infected population.

Acute Radiologic Manifestations of America’s Opioid Epidemic

The United States is in the midst of an opioid use epidemic, which has severe medical, social, and economic consequences. Addictions to and abuse of prescription and illicit opioids are increasing, and emergency department radiologists are increasingly being faced with the task of examining patients who present with opioid-related complications. These complications may be the result of direct drug toxicity or nonsterile injection of the drugs. Neurologic, musculoskeletal, cardiopulmonary, genitourinary, and gastrointestinal complications may be evident at diagnostic imaging in emergent settings. Heroin-induced leukoencephalopathy, cerebral septic emboli, mycotic arterial aneurysms, soft-tissue infections, and infective endocarditis are some of the conditions that patients may be found to have after they present to the emergency department. In this article, the above topics, including clinical features, pathophysiology, imaging findings, and treatment options, are reviewed. Recognizing the limitations of diagnostic imaging modalities that are available to radiologists is equally important, as some conditions can be successfully diagnosed after the initial triage-for example, transesophageal echocardiography can be performed to diagnose infective endocarditis. The emergency department radiologist may be responsible for identifying acute conditions, which can be life threatening. Some of the more common emergent opioid-related conditions and complications are reviewed, with specific emphasis on cases in which emergency department radiologists encounter conditions for which additional expertise is required. Becoming familiar with the conditions directly related to the current opioid epidemic will enable the diagnosis of these entities in a timely and accurate manner. ©RSNA, 2018.