Efficacy of Whole-Blood Model of Gadolinium-Based Contrast Agent Relaxivity in Predicting Vascular MR Signal Intensity In Vivo.

Background: Previous in vitro studies have described sub-linear longitudinal and heightened transverse HO relaxivities of gadolinium-based contrast agents (GBCAs) in blood due to their extracellular nature. However, in vivo validation is lacking.

Purpose: Validate theory describing blood behavior of R and R* in an animal model.

Relationship Between Simulated Gadolinium-Based Contrast Agent Injection Profile and Achievable Resolution Metrics in Contrast-Enhanced Magnetic Resonance Angiography.

Background: Contrast bolus variation during contrast-enhanced magnetic resonance angiography (CE-MRA) acquisition may lead to vessel blurring.

Purpose: To combine knowledge of how contrast signal intensity (SI) evolves for different injection strategies with anatomically familiar parametric computer models to measure and visually assess the effects of a wide range of variables on modeled CE-MRA, and in doing so develop contrast rate injection guidelines.

Study Type: Computer modeling.

Comparison of Histogram-Based Gaussian Analysis With and Without Noise Correction for the Characterization of Indeterminate Adrenal Nodules.

The purpose of this study is to determine whether gaussian-based histogram analysis without and with noise correction can characterize indeterminate adrenal nodules (those with attenuation greater than 10 HU on unenhanced CT) as lipid-poor adenomas. This retrospective study evaluated adrenal nodules larger than 1 cm on unenhanced CT using gaussian analysis without and with noise correction on intralesional ROIs. Two independent readers who were blinded to the final diagnoses evaluated the nodules.

Non-invasive diagnostic criteria of hepatocellular carcinoma: Comparison of diagnostic accuracy of updated LI-RADS with clinical practice guidelines of OPTN-UNOS, AASLD, NCCN, EASL-EORTC, and KLSCG-NCC.

Purpose: To retrospectively compare the diagnostic performance of different noninvasive diagnostic criteria of HCC including LI-RADS, OPTN-UNOS, AASLD, NCCN, EASL-EORTC, KLCSG-NCC.

Materials And Methods: We reviewed the medical records of 3,491 pathologically examined liver lesions from January-2011 to January-2015 in our institution. 195 lesions in 133 patients (M:F = 100:33) with chronic hepatitis B/C and/or cirrhosis for any etiology were finally included in our study, with 98 lesions ≥ 2 cm, 72 lesions between 1-2 cm, and 25 lesions < 1 cm.

Response to Immunotherapy in Combination With Mitotane in Patients With Metastatic Adrenocortical Cancer.

Adrenocortical carcinoma (ACC) is a rare orphan disease with a dismal prognosis. Surgery remains the first-line treatment, but most patients eventually develop metastatic disease. Mitotane is often used with chemotherapy with modest success.

Development of an Adrenocortical Cancer Humanized Mouse Model to Characterize Anti-PD1 Effects on Tumor Microenvironment.

Context: Although the development of immune checkpoint inhibitors has transformed treatment strategies of several human malignancies, research models to study immunotherapy in adrenocortical carcinoma (ACC) are lacking.

Objective: To explore the effect of anti-PD1 immunotherapy on the alteration of the immune milieu in ACC in a newly generated preclinical model and correlate with the response of the matched patient.

Design, Setting, And Intervention: To characterize the CU-ACC2-M2B patient-derived xenograft in a humanized mouse model, evaluate the effect of a PD-1 inhibitor therapy, and compare it with the CU-ACC2 patient with metastatic disease.

Evaluation of four injection profiles for uniform contrast-enhanced signal intensity profiles in MR angiography.

Background: Gadolinium concentration variation during acquisition of contrast-enhanced MR angiography (CE-MRA) may lead to artifacts.

Purpose: To compare signal intensity (SI) profiles of four different contrast agent injection strategies during CE-MRA with the goal of minimizing SI variation during acquisition.

Study Type: Prospective.

Risk Threshold Algorithm for Thyroid Nodule Management Demonstrates Increased Specificity and Diagnostic Accuracy as Compared With American College of Radiology Thyroid Imaging, Reporting and Data System; Society of Radiologists in Ultrasound; and American Thyroid Association Management Guidelines.

We studied diagnostic performance of an algorithm guiding thyroid nodule management using a malignancy risk model as compared with extant management guidelines. Single-institution, retrospective study was performed with sequential cases from pathology registry from 2012 to 2015. Seventy-eight patients were enrolled, with benign and malignant groups defined by aspiration results.

Evaluation of diagnostic accuracy: multidetector CT image noise correction improves specificity of a Gaussian model-based algorithm used for characterization of incidental adrenal nodules.

Objectives: To investigate whether the histogram analysis method of characterizing adrenal nodules as adenomas is affected by increased noise with modern CT technique, and if an extension that allows for noise correction will improve diagnostic performance.

Materials And Methods: This is a HIPAA-compliant, IRB-approved retrospective study performed on 58 total patients. The first group of 29 patients had 33 adrenal lesions that were pathology-proven non-adenomas.

Increased Incidence of Pseudoaneurysm Bleeding With Lumen-Apposing Metal Stents Compared to Double-Pigtail Plastic Stents in Patients With Peripancreatic Fluid Collections.

Background & Aims: There have been few studies that compared the effects of lumen-apposing metal stents (LAMS) and double-pigtail plastic stents (DPS) in patients with peripancreatic fluid collections from pancreatitis. We aimed to compare technical and clinical success and adverse events in patients who received LAMS vs DPS for pancreatic pseudocysts and walled-off necrosis.

Methods: We performed a retrospective study of endoscopic ultrasound-mediated drainage in 149 patients (65% male; mean age, 47 y) with pancreatic pseudocysts or walled-off necrosis (97 received LAMS and 152 received DPS), from January 2011 through September 2016 at a single center.

Effect of injection rate on contrast-enhanced MR angiography image quality: Modulation transfer function analysis.

Purpose: Contrast-enhanced (CE)-MRA optimization involves interactions of sequence duration, bolus timing, contrast recirculation, and both R relaxivity and R2*-related reduction of signal. Prior data suggest superior image quality with slower gadolinium injection rates than typically used.

Methods: A computer-based model of CE-MRA was developed, with contrast injection, physiologic, and image acquisition parameters varied over a wide gamut.

Characterization of Adrenal Adenoma by Gaussian Model-Based Algorithm.

We confirmed that computed tomography (CT) attenuation values of pixels in an adrenal nodule approximate a Gaussian distribution. Building on this and the previously described histogram analysis method, we created an algorithm that uses mean and standard deviation to estimate the percentage of negative attenuation pixels in an adrenal nodule, thereby allowing differentiation of adenomas and nonadenomas. The institutional review board approved both components of this study in which we developed and then validated our criteria.

Lung CT Screening Reporting and Data System Speed and Accuracy Are Increased With the Use of a Semiautomated Computer Application.

Purpose: The Lung CT Screening Reporting and Data System (Lung-RADS™) is an algorithm that can be used to classify lung nodules in patients with significant smoking histories. It is published in table format but can be implemented as a computer program. The aim of this study was to assess the efficiency and accuracy of the use of a computer program versus the table in categorizing lung nodules.

Thyroid Nodule Doubling Time is Not a Reliable Indicator of Benign or Malignant Nature.

Thyroid nodules are often followed up with serial ultrasound imaging. Doubling time is well established in the evaluation of lung nodules. We examined whether benign and malignant thyroid nodules exhibit differences in doubling time.

Computed tomography of acute heart failure: A novel case and literature review.

Computed tomography (CT) is used in patients whose conditions span the gamut from healthy to critically ill. In the specific subset of patients with cardiac arrest or imminent cardiac failure who receive contrast-enhanced CT, extant literature illustrates a set of imaging findings that include inferior vena cava and hepatic parenchymal contrast reflux, pooling, and layering in a dependent fashion. We review the literature and present a case in which these findings are demonstrated along with renal venointerstitial reflux, a finding that has not been previously described.

Design and implementation of handheld and desktop software for the structured reporting of hepatic masses using the LI-RADS schema.

Rationale And Objectives: The Liver Imaging Reporting and Data System (LI-RADS) can enhance communication between radiologists and clinicians if applied consistently. We identified an institutional need to improve liver imaging report standardization and developed handheld and desktop software to serve this purpose.

Materials And Methods: We developed two complementary applications that implement the LI-RADS schema.

Splenic trauma: pictorial review of contrast-enhanced CT findings.

Splenic trauma is a common entity of high clinical significance that may have a variety of imaging manifestations. This article reviews splenic anatomy and function, mechanisms of splenic trauma, and the classification and grading of splenic trauma, with a particular focus on contrast-enhanced CT. Heterogeneous early enhancement of the spleen and technical suggestions to minimize this artifact are discussed.