A polygenic risk score for the QT interval is an independent predictor of drug-induced QT prolongation.

Drug-induced QT prolongation (diLQTS), and subsequent risk of torsade de pointes, is a major concern with use of many medications, including for non-cardiac conditions. The possibility that genetic risk, in the form of polygenic risk scores (PGS), could be integrated into prediction of risk of diLQTS has great potential, although it is unknown how genetic risk is related to clinical risk factors as might be applied in clinical decision-making. In this study, we examined the PGS for QT interval in 2500 subjects exposed to a known QT-prolonging drug on prolongation of the QT interval over 500ms on subsequent ECG using electronic health record data. We found that the normalized QT PGS was higher in cases than controls (0.212±0.954 vs. -0.0270±1.003, P = 0.0002), with an unadjusted odds ratio of 1.34 (95%CI 1.17-1.53, P<0.001) for association with diLQTS. When included with age and clinical predictors of QT prolongation, we found that the PGS for QT interval provided independent risk prediction for diLQTS, in which the interaction for high-risk diagnosis or with certain high-risk medications (amiodarone, sotalol, and dofetilide) was not significant, indicating that genetic risk did not modify the effect of other risk factors on risk of diLQTS. We found that a high-risk cutoff (QT PGS ≥ 2 standard deviations above mean), but not a low-risk cutoff, was associated with risk of diLQTS after adjustment for clinical factors, and provided one method of integration based on the decision-tree framework. In conclusion, we found that PGS for QT interval is an independent predictor of diLQTS, but that in contrast to existing theories about repolarization reserve as a mechanism of increasing risk, the effect is independent of other clinical risk factors. More work is needed for external validation in clinical decision-making, as well as defining the mechanism through which genes that increase QT interval are associated with risk of diLQTS.

Exploring Dual-Energy CT Spectral Information for Machine Learning-Driven Lesion Diagnosis in Pre-Log Domain.

In this study, we proposed a computer-aided diagnosis (CADx) framework under dual-energy spectral CT (DECT), which operates directly on the transmission data in the pre-log domain, called CADxDE, to explore the spectral information for lesion diagnosis. The CADxDE includes material identification and machine learning (ML) based CADx. Benefits from DECT's capability of performing virtual monoenergetic imaging with the identified materials, the responses of different tissue types (e.g., muscle, water, and fat) in lesions at each energy can be explored by ML for CADx. Without losing essential factors in the DECT scan, a pre-log domain model-based iterative reconstruction is adopted to obtain decomposed material images, which are then used to generate the virtual monoenergetic images (VMIs) at selected n energies. While these VMIs have the same anatomy, their contrast distribution patterns contain rich information along with the n energies for tissue characterization. Thus, a corresponding ML-based CADx is developed to exploit the energy-enhanced tissue features for differentiating malignant from benign lesions. Specifically, an original image-driven multi-channel three-dimensional convolutional neural network (CNN) and extracted lesion feature-based ML CADx methods are developed to show the feasibility of CADxDE. Results from three pathologically proven clinical datasets showed 4.01% to 14.25% higher AUC (area under the receiver operating characteristic curve) scores than the scores of both the conventional DECT data (high and low energy spectrum separately) and the conventional CT data. The mean gain >9.13% in AUC scores indicated that the energy spectral-enhanced tissue features from CADxDE have great potential to improve lesion diagnosis performance.

The many faces of cirrhosis.

There are many different imaging features of cirrhosis, some of which are less commonly recognized. It is important that the radiologist is familiar with these features as cirrhosis can be first discovered on imaging performed for other indications, thus alerting the clinician for the need to screen for complications of cirrhosis and referral for potential treatment. This article reviews the various imaging findings of cirrhosis seen on cross-sectional imaging of the abdomen and pelvis.

Transpedicular-Transdiscal Cement Augmentation Treatment of Thoracolumbar Fusion Proximal Junctional Failure.

BACKGROUND: Long instrumented fusions for adult deformity have a proximal junction kyphosis rate between 20% and 40%. When symptomatic, proximal junctional failure (PJF) often requires revision surgery and is associated with significant morbidity. Vertebral cement augmentation (VCA) has been used for prophylaxis against PJF but has not been previously described as treatment after onset of PJF has occurred. We describe a series of patients with PJF of long posterior spinal fusions that were treated at our institution using a novel VCA technique. METHODS: Three patients with PJF above thoracolumbopelvic fusions were retrospectively reviewed following treatment with transpedicular-transdiscal VCA. The medical record was reviewed for demographic data, outcomes scores, and radiographic images. RESULTS: Mean age was 69.3 years. Mean follow-up was 13.3 months. Mean preprocedure visual analog scale score was 8.67, and postprocedure visual analog scale score was 4.00. Mean preprocedure sagittal balance was 9.7 cm, and postprocedure sagittal balance was 5.8 cm. No patients required revision surgery for PJF in the follow-up period. CONCLUSIONS: Transpedicular-transdiscal VCA treatment for PJF is safe and may have the potential to prevent the need for revision surgery. LEVEL OF EVIDENCE: 4.

Postoperative CT of the Mandible Following Trauma: Review of Normal Appearances and Common Complications.

RATIONALE AND OBJECTIVES: Surgeons aim to restore occlusion and jaw function to baseline status for patients with mandibular fractures using either closed treatment or reduction and fixation. MATERIALS AND METHODS: Occlusion is defined as the relationship between the maxillary and mandibular teeth as they approach each other. RESULTS: Radiologists should be familiar with the goals of repair to help identify which treatment is adequate as well as to diagnose potential complications. Some of the more common complications encountered are infection, nonunion or malunion, and malocclusion. CONCLUSION: We provide a comprehensive review of both the desired and untoward CT findings after surgical repair of traumatic mandibular injuries.

Frequency and distribution of incidental findings deemed appropriate for S modifier designation on low-dose CT in a lung cancer screening program.

PURPOSE: To describe the frequency, distribution and reporting patterns of incidental findings receiving the Lung-RADS S modifier on low-dose chest computed tomography (CT) among lung cancer screening participants. METHODS: This retrospective investigation included 581 individuals who received baseline low-dose chest CT for lung cancer screening between October 2013 and June 2017 at a single center. Incidental findings resulting in assignment of Lung-RADS S modifier were recorded as were incidental abnormalities detailed within the body of the radiology report only. A subset of 60 randomly selected CTs was reviewed by a second (blinded) radiologist to evaluate inter-rater variability of Lung-RADS reporting. RESULTS: A total of 261 (45%) participants received the Lung-RADS S modifier on baseline CT with 369 incidental findings indicated as potentially clinically significant. Coronary artery calcification was most commonly reported, accounting for 182 of the 369 (49%) findings. An additional 141 incidentalomas of the same types as these 369 findings were described in reports but were not labelled with the S modifier. Therefore, as high as 69% (402 of 581) of participants could have received the S modifier if reporting was uniform. Inter-radiologist concordance of S modifier reporting in a subset of 60 participants was poor (42% agreement, kappa = 0.2). CONCLUSIONS: Incidental findings are commonly identified on chest CT for lung cancer screening, yet reporting of the S modifier within Lung-RADS is inconsistent. Specific guidelines are necessary to better define potentially clinically significant abnormalities and to improve reporting uniformity.

Postoperative CT of the Midfacial Skeleton After Trauma: Review of Normal Appearances and Common Complications.

OBJECTIVE: The objective of this article is to describe the CT appearance of the midfacial skeleton after surgical repair of posttraumatic Le Fort, nasoorbitoethmoidal (NOE), and frontal sinus fractures. Several of the more commonly encountered complications will also be described. CONCLUSION: Surgery after midfacial trauma is aimed at restoring both form and function. Knowledge of the principal tenets of Le Fort, NOE, and frontal sinus fracture repair is vital for radiologists to accurately assess the adequacy of treatment on postoperative CT and provide meaningful reports for the surgeon.

Dual-energy Computed Tomography for the Evaluation of Enhancement of Pulmonary Nodules≤3 cm in Size.

PURPOSE: The aim of the study was to compare the accuracies of 4 different methods of assessing pulmonary nodule enhancement to distinguish benign from malignant solid pulmonary nodules using nondynamic contrast-enhanced dual-energy computed tomography. MATERIALS AND METHODS: Seventy-two patients (mean age, 62 y) underwent dual-energy chest computed tomography 3 minutes after intravenous contrast administration. Each of 118 pulmonary nodules (9±5.9 mm) were evaluated for enhancement by 4 methods: visual assessment, 3-dimensional automated postprocessing measurement tool, manually drawn region of interest with calculated iodine-related attenuation, and measurement of iodine concentration. The optimal cutoff for enhancement was defined as having the largest specificity among all cutoffs while maintaining 100% sensitivity. Accuracy of the methods was assessed with receiver operating characteristic curves. RESULTS: Ninety-three of 118 pulmonary nodules were benign (79%). Visual assessment of enhancement had sensitivity and specificity of 100% and 44%, respectively. For the automated 3-dimensional measurement tool, 20 HU was found to be the optimal threshold for defining enhancement, resulting in a specificity of 71% and a sensitivity of 100%, as well as an area under the curve (AUC) of 0.87 (95% confidence interval [CI], 0.82-0.92). The AUC was 0.79 (95% CI, 0.73-0.85) for the measured enhancement using a manually drawn region of interest. When a threshold of 21 HU was used for defining enhancement, maximum specificity was obtained (56%) while maintaining 100% sensitivity. The AUC for measured iodine concentration was 0.79 (95% CI, 0.77-0.85). At a cutoff iodine concentration of 0.6 mg/mL, the sensitivity was 100% with a specificity of 57%. CONCLUSIONS: Although use of automated postprocessing had the highest specificity while maintaining 100% sensitivity, there were only minor clinically relevant differences between measurement techniques given that no single technique misclassified a malignant nodule as nonenhancing.

Magnetic Resonance Imaging Characteristics of a Baerveldt Glaucoma Implant.

PURPOSE: Evaluate for normative postoperative magnetic resonance imaging (MRI) characteristics of a Baerveldt Glaucoma Implant (BGI). DESIGN: Prospective case series. PARTICIPANTS: Seven subjects with uncontrolled glaucoma requiring a primary superotemporal BGI. METHODS: Subjects prospectively underwent sequential MRI orbital scans without contrast at 0 to 2 weeks, 6 to 8 weeks, and 4 to 6 months after implantation of a BGI model 103-250. Masked to the postoperative time course, a radiologist measured bleb and implant characteristics. MAIN OUTCOME MEASURES: Linear measurements of the maximum bleb height at the anterior, middle, and posterior sections of the endplate were measured. Intraocular pressure (IOP) was correlated to bleb height. RESULTS: On axial T2-weighted images, the height of fluid below and above the BGI endplate increased from the initial to the final MRI images: 0.49 mm to 1.83 mm and 0.57 mm to 1.08 mm (middle 1/3), respectively. On coronal T2-weighted images, fluid below and above the BGI endplate increased from 0.47 mm to 1.53 mm and 0.49 mm to 1.38 mm, respectively. Maximum inverse correlation between bleb height and IOP was observed at the 6 to 8 week coronal T2 images (r=-0.963, P=0.002). CONCLUSIONS: Fluid collections and endplate characteristics are easily visualized with MRI. Dynamic changes occur over the early postoperative time course. Bleb height is inversely correlated to IOP at 6 to 8 weeks, but disappears at 4 to 6 months.

Mild asymptomatic intrahepatic biliary dilation after cholecystectomy, a common incidental variant.

OBJECTIVE: The purpose of this study is to evaluate the prevalence of intra- and extrahepatic ductal dilatation in asymptomatic individuals after cholecystectomy. METHODS AND MATERIALS: This IRB-approved retrospective cohort study evaluated the prevalence of intra- and extrahepatic biliary dilation in 77 consecutive post cholecystectomy patients who had CT obtained in the portal venous phase. These were then compared to age and sex matched control patients. Two radiologists in consensus blinded to surgical history evaluated the intrahepatic ducts qualitatively for dilatation. A single radiologist using the best of three orthogonal planes measured the extrahepatic ducts. Extrahepatic ducts were considered dilated if >7 mm plus 1 mm/decade after 60 years. T tests and chi-squared tests were performed. RESULTS: Cholecystectomy patient duct patterns: normal ducts 26% (20/77); intra- and extrahepatic dilation 31.2% (24/77); intrahepatic dilation only 18.2% (14/77); extrahepatic dilation only 24.7% (19/77). Control patient duct patterns: normal ducts 88.3% (68/77); intra- and extrahepatic dilation 2.6% (2/77); intrahepatic dilation only 2.6% (2/77); extrahepatic dilation only 6.5% (5/77). All intrahepatic ductal dilatation was mild. Total intrahepatic dilation: 49.4% (cholecystectomy); 5.2% (control patients). The relative risk of intrahepatic ductal dilation in cholecystectomy patients was 9.5:1. Increased prevalence of intra- and extrahepatic dilation in cholecystectomy patients was statistically significant (p < 0.0001). Average extrahepatic duct was 7.8 mm (cholecystectomy) and 5.3 mm (control patients) (p < 0.001). CONCLUSION: Mild intrahepatic biliary dilation in the setting of cholecystectomy is very common, and if not associated with clinical or biochemical evidence of obstruction is likely of no clinical significance.

Postoperative CT of the Orbital Skeleton After Trauma: Review of Normal Appearances and Common Complications.

OBJECTIVE: The purpose of this article is to describe both the expected and unexpected imaging features of posttraumatic defects of the orbital skeleton after surgical repair. CONCLUSION: The goal of surgery is to restore the preinjury orbital anatomy to improve function and prevent enophthalmos. Radiologists need to be cognizant of the more frequently encountered operative procedures used for orbital fracture repair, the desired goals of treatment, and common complications. This will permit accurate interpretation of postoperative CT and provide surgeons with clinically useful results.

Improving Patient Satisfaction Through Computer-Based Questionnaires.

Patient-reported outcome measures are helping clinicians to use evidence-based medicine in decision making. The use of computer-based questionnaires to gather such data may offer advantages over traditional paper-based methods. These advantages include consistent presentation, prompts for missed questions, reliable scoring, and simple and accurate transfer of information into databases without manual data entry. The authors enrolled 308 patients over a 16-month period from 3 orthopedic clinics: spine, upper extremity, and trauma. Patients were randomized to complete either electronic or paper validated outcome forms during their first visit, and they completed the opposite modality at their second visit, which was approximately 7 weeks later. For patients with upper-extremity injuries, the Penn Shoulder Score (PSS) was used. For patients with lower-extremity injuries, the Foot Function Index (FFI) was used. For patients with lumbar spine symptoms, the Oswestry Disability Index (ODI) was used. All patients also were asked to complete the 36-Item Short Form Health Survey (SF-36) Health Status Survey, version 1. The authors assessed patient satisfaction with each survey modality and determined potential advantages and disadvantages for each. No statistically significant differences were found between the paper and electronic versions for patient-reported outcome data. However, patients strongly preferred the electronic surveys. Additionally, the paper forms had significantly more missed questions for the FFI (P<.0001), ODI (P<.0001), and PSS (P=.008), and patents were significantly less likely to complete these forms (P<.0001). Future research should focus on limiting the burden on responders, individualizing forms and questions as much as possible, and offering alternative environments for completion (home or mobile platforms).

Effect of Low-Osmolar Intravenous Contrast on Renal Length.

OBJECTIVE: The purpose was to study the effect of low-osmolar nonionic contrast on renal length. MATERIAL AND METHODS: This study included 56 patients (4-phase renal computed tomography [CT] and 4-phase CT urogram [CTU], 19 patients each; split-phase CTU, 18 patients). Three radiologists created the best off-axis plane and renal lengths measured on a postprocessing workstation. Two-way analysis of variance with Bonferroni corrections was performed along with single-sample t tests. RESULTS: Four-phase renal CT and CTU average differences from unenhanced phases were 0.30/0.16 mm (corticomedullary), 0.88/1.33 mm (nephrographic), and 2.17/2.22 mm (delayed). The nephrographic and delayed phases were significantly different from their unenhanced phase (P < 0.01). Nonsignificant differences between the corticomedullary phase and the unenhanced phase were observed (P = 0.217, 4-phase renal CT; P = 0.232, 4-phase CTU). The split-phase CTU average difference in the enhanced phase was 1.36 mm (P < 0.001). CONCLUSION: Renal length increases 1 to 2 mm with low-osmolar nonionic contrast.

Multiplanar Reformations in the Measurement of Renal Length on CT: Is It Plain Which Plane to Use?

OBJECTIVE: The objective of this study was to determine the accuracy of renal measurement on CT in multiple imaging planes. MATERIALS AND METHODS: In this study, three board-certified radiologists retrospectively measured 110 kidneys on CT in 55 consecutive patients. Five measurement methods were used: axial, coronal single image, coronal multiimage, sagittal single image, and sagittal multiimage. The coronal database was sent to a postprocessing workstation, and each radiologist performed a maximum renal measurement using a best off-axis plane that was our reference standard. An ANOVA test with repeated measures and posthoc Bonferroni corrected t tests were performed. RESULTS: The mean differences (± standard error) compared with the reference standard method were as follows: axial, 7.7 ± 0.7 mm; coronal single image, 13.1 ± 1.4 mm; coronal multiimage, 6.4 ± 0.8 mm; sagittal single image, 6.4 ± 0.6 mm; and sagittal multiimage, 2.8 ± 0.3 mm. The reference standard measurement was larger (p < 0.001), whereas the coronal single-image measurement (p ≤ 0.006) was smaller than all other methods. The sagittal multiimage (p ≤ 0.005) was statistically significantly different from all other methods. There were no statistically significant differences among the axial, coronal multiimage, and sagittal single-image methods (p ≥ 0.088). CONCLUSION: The single-image coronal method is the least accurate, with an error of approximately 13 mm. The axial, multiimage coronal, and single-image sagittal methods underestimate renal size by approximately 6-8 mm. Multiimage sagittal is the most accurate method for measuring kidneys with an error of approximately 3 mm.

Review of Commonly Used Serum Tumor Markers and Their Relevance for Image Interpretation.

Serum tumor markers are firmly entrenched as one of the primary tools in an oncologist's armamentarium. They can be implemented in a broad range of applications from diagnostic assistance, assessing prognosis, or guiding therapeutic decisions. However, tumor markers also have limitations, which significantly impact how they should be used. Radiologists should be familiar with the following most prevalent tumor markers, which will all be discussed here: prostate-specific antigen (prostate), carcinoembryonic antigen (colon), α-fetoprotein (hepatocellular and testicular), carbohydrate antigen 19.9 (pancreas), cancer antigen 125 (ovarian), human chorionic gonadotropin/lactic dehydrogenase (testicular), and chromogranin A (neuroendocrine). This knowledge should avoid needless intervention, enhance image interpretation, and ultimately provide optimal patient care.

Can a T2 hyperintense rim sign differentiate uterine leiomyomas from other solid adnexal masses?

PURPOSE: To investigate the incidence of high T2 signal rims surrounding leiomyomas, evaluate if a particular T2-weighted sequence is more effective in depicting this rim, and determine if this sign is useful in differentiating pedunculated leiomyomas from other solid adnexal masses. MATERIALS AND METHODS: In this retrospective study, two radiologists evaluated 233 T2 dark pelvic masses (223 uterine leiomyomas and 10 ovarian fibromas) in 60 women (mean age 47) on Magnetic resonance imaging for the presence of a high signal rim. Three different T2-weighted sequences were reviewed independently for uterine leiomyomas: half-Fourier acquisition single-shot turbo spin echo (HASTE), SPACE, and T2 with fat saturation (T2 FS). Only T2 FS images were available for 10 fibromas. A consensus review was conducted for discrepant cases. Statistical analyses were performed using Fisher's exact test, kappa test, and ANOVA RESULTS: For 223 uterine leiomyomas, 23% (95% CI 17.8-28.9%) demonstrated a high T2 signal rim sign on T2 FS compared with 4.9% (95% CI 2.6-8.9%) for HASTE and 6.7% (95% CI 3.9-11.1%) for SPACE. The difference between the number of positive rims on T2 FS relative-HASTE and SPACE was statistically significant (p < 0.001). For ovarian fibromas, 40% (95% CI 16.9-68.8%) were classified positive for a rim sign. CONCLUSION: A high T2 signal rim sign was present for up to 23% of uterine leiomyomas and the T2 FS sequence detected this rim sign most frequently. Up to 40% of ovarian fibromas can also have a T2 rim sign and, therefore, a solid adnexal mass with a T2 rim sign cannot be assumed to represent a pedunculated leiomyoma.

Role of imaging for patients with colorectal hepatic metastases: what the radiologist needs to know.

Surgical resection of colorectal metastatic disease has increased as surgeons have adopted a more aggressive ideology. Current exclusion criteria are patients for whom a negative resection margin is not feasible or a future liver remnant (FLR) of greater than 20% is not achievable. The goal of preoperative imaging is to identify the number and distribution of liver metastases, in addition to establishing their relation to relevant intrahepatic structures. FLR can be calculated utilizing cross-sectional imaging to select out patients at risk for hepatic dysfunction after resection. MRI, specifically with gadoxetic acid contrast, is currently the preferred modality for assessment of hepatic involvement for patients with newly diagnosed colorectal cancer, to include those who have undergone neoadjuvant chemotherapy. Employment of liver-directed therapies has recently expanded and they may provide an alternative to hepatectomy in order to obtain locoregional control in poor surgical candidates or convert patients with initially unresectable disease into surgical candidates.

Gadoxetic acid: pearls and pitfalls.

Gadoxetic acid is a hepatocyte-specific magnetic resonance imaging contrast agent with the ability to detect and characterize focal liver lesions and provide structural and functional information about the hepatobiliary system. Knowledge of the pharmacokinetics of gadoxetic acid is paramount to understanding imaging protocol and lesion appearance and facilitates identification and avoidance of undesired effects with use of this intravenous contrast agent. This article reviews the utility of gadoxetic acid in liver and biliary imaging, with emphasis on the hepatobiliary phase.

Surgical management of retrorectal lesions: what the radiologist needs to know.

OBJECTIVE. The purpose of this article is to highlight the most salient imaging features of retrorectal masses with regard to surgical planning, preoperative biopsy, and identification of nonneoplastic mimickers of malignancy. CONCLUSION. Retrorectal tumors are associated with high morbidity. CT and MRI aid in preoperative planning because surgical resection is the treatment of choice for both benign and malignant entities. Radiologists need to understand the operative techniques currently used for retrorectal tumors because the first attempt at excision is the best chance for complete resection and optimal outcome.