Imaging Depiction of Hypoxic Pulmonary Vasoconstriction Using Dual-Energy CT.

In this article, we aim to highlight the utility of dual-energy computed tomography (DECT) in demonstrating imaging changes due to hypoxic pulmonary vasoconstriction (HPV). DECT allows detailed image reconstructions that have been shown to better characterize cardiothoracic pathologies, as compared to conventional CT techniques. DECT simultaneously detects two different X-ray energies, which enables generation of iodine density maps, virtual monoenergetic images, and effective atomic number maps (Zeff), among others. DECT has been shown to have utility in the assessment of benign versus malignant pulmonary nodules, pulmonary embolism, myocardial perfusion defects, and other conditions. Herein, we describe four cases of indeterminate pulmonary pathology when imaged with conventional CT in which subsequent use of DECT-derived image reconstructions demonstrated HPV as the underlying pathophysiological mechanism. The goal of this article is to understand the imaging appearance of HPV on DECT and discuss how HPV may mimic other causes of perfusion defects.

Coronary Artery Calcium Scoring: Current Status and Future Directions.

Coronary artery calcium (CAC) scores obtained from CT scans have been shown to be prognostic in assessment of the risk for development of cardiovascular diseases, facilitating the prediction of outcome in asymptomatic individuals. Currently, several methods to calculate the CAC score exist, and each has its own set of advantages and disadvantages. Agatston CAC scoring is the most extensively used method. CAC scoring is currently recommended for use in asymptomatic individuals to predict the risk of developing cardiovascular diseases and the disease-specific mortality. In specific subsets of patients, the CAC score has also been recommended for reclassifying cardiovascular risk and aiding in decision making when planning primary prevention interventions such as statin therapy. The progression of CAC scores on follow-up images has been shown to be linked to risk of myocardial infarction and cardiovascular mortality. While the CAC score is a validated tool used clinically, several challenges, including various pitfalls associated with the acquisition, calculation, and interpretation of the score, prevent more widespread adoption of this metric. Recent research has been focused extensively on strategies to improve existing scoring methods, including measuring calcium attenuation, detecting microcalcifications, and focusing on extracoronary calcifications, and on strategies to improve image acquisition. A better understanding of CAC scoring approaches will help radiologists and other physicians better use and interpret these scores in their workflows. An invited commentary by S. Gupta is available online. Online supplemental material is available for this article. ©RSNA, 2022.

Pulmonary Embolism Versus Mimics on Dual-energy Spectral Computed Tomography: An Algorithmic Approach.

Pulmonary embolism is a commonly encountered diagnosis that is traditionally identified on conventional computed tomography angiography. Dual-energy computed tomography (DECT) is a new technology that may aid the initial identification and differential diagnosis of pulmonary embolism. In this review, we present an algorithmic approach for assessing pulmonary embolism on DECT, including acute versus chronic pulmonary embolism, relationship to conventional computed tomography angiography, surrogate for likelihood of hemodynamic significance, and alternative diagnoses for DECT perfusion defects.

Preoperative assessment of lung nodules and lobar function by spectral detector computed tomography.

Conventional computed tomography (CT) plays an important role in detection of lung nodules. However, further characterization is usually limited requiring additional imaging and invasive work up. Spectral Detector CT (SDCT) is an upcoming novel modality that not only allows morphological evaluation but also provides insight into prediction of malignant behavior of lung nodules. Additional quantification capabilities available from the same scan make it a more comprehensive imaging option in oncology patients. This is a first case report demonstrating the potential of single SDCT to provide necessary information for lung cancer diagnosis and preoperative planning, comparable to standard of care imaging.

E-cigarette use related lung disease, review of clinical and imaging findings in 3 cases.

Electronic-cigarette use (vaping), has gained popularity among the young adult population, causing an alarming rise in electronic-cigarette, or vaping, product use-associated lung injury (EVALI). The specific chemical agent(s) responsible for lung injuries remains to be further investigated, but tetrahydrocannabinol, the active ingredient in marijuana, and vitamin E acetate are involved in most cases. A variety of pulmonary diseases causing different imaging findings have been described with EVALI. The clinical and imaging findings of three cases recently seen in our emergency department are reviewed.

Role of Vitamin-D Deficiency in Term Neonates with Late-Onset Sepsis: A Case-Control Study.

OBJECTIVE: To find the relationship between vitamin-D levels and late-onset sepsis (LOS) in term neonates. METHODS: This case-control study was conducted in neonatal intensive care unit of a tertiary care teaching institution in central India. Full-term neonates with culture-proven LOS were taken as cases. Maternal and neonatal demography, clinical examination and investigations were recorded. Correlation of vitamin-D deficiency (<20 ng/ml) with LOS was assessed. RESULTS: Total 225 term neonates including 175 cases and 50 controls were included. Maternal and neonatal demographic profile was comparable. The mean vitamin-D level in cases (12.28 ± 6.11 ng/ml) was significantly lower than that in controls (14.88 ± 7.2 ng/ml) (p = 0.002). Total 151 (86.29%) neonates out of 175 cases and 37 (74%) out of 50 controls had the vitamin-D deficiency (p = 0.00003). On multiple regression analysis, neonatal sepsis (p = 0.00003) was found to be significantly associated with vitamin-D deficiency. CONCLUSION: This study shows that vitamin-D deficiency in term neonates may predispose them to LOS.

Effect of preeclampsia on insulin sensitivity.

OBJECTIVE: The objective of this study is to investigate whether preeclampsia is associated with exacerbation of insulin resistance. MATERIALS AND METHODS: The study was conducted over a period of 7 months from November 2011 to May 2012, in a tertiary care hospital attached to a medical college. A total of 14 pregnant women in the third trimester with preeclampsia were recruited for this study and 14 well-matched normotensive women in the third trimester were taken as control. 15 g, 50% dextrose load was given intravenously and blood sampling was carried out for glucose and insulin levels up to 3 h afterward. Minimal model analysis of glucose and insulin levels was performed to arrive at results. RESULTS: No significant changes in mean age, body mass index, gestation, serum lipid and progesterone, cortisol and androgen concentrations were recognized. No significant difference was found between the glucose decay curves and between the glucose clearance rate K, in the two groups (preeclamptic vs. normotensive: 2.1 ± 0.2 vs. 2.2 ± 0.3; P = 0.48). Therefore, there was a small but prolonged decrease in the insulin response of women with preeclampsia compared with women in the normotensive group. CONCLUSION: Preeclampsia per se is not a risk factor for development of insulin resistance.