We report a case wherein adrenal function remained preserved despite bilateral adrenal infarction, as evidenced by dual-energy computed tomography (DECT) iodine density images. The patient was a 37-year-old man with a history of antiphospholipid syndrome concomitant with systemic lupus erythematosus. The patient underwent contrast-enhanced DECT, which revealed bilateral adrenal infarction. Laboratory tests revealed preserved adrenal function. On the iodine density images, the infarcted and noninfarcted areas in the adrenal glands were visually different. The volume of the non-infarcted area was 8.9 mL, which was 41% of the total adrenal volume. DECT may be a useful complementary tool for assessing the preservation of adrenal function.

Bone damage, a late side effect of radiotherapy, occurs concurrently with the replacement of fat cells in the bone marrow, causing changes in bone composition. Changes in composition can affect bone quality and disease states, and reduced bone mass can reduce quality of life by increasing the risk of fractures. A 70-year-old woman presented to the orthopedic outpatient clinic with the chief complaint of lower-back pain. The patient reported no history of trauma but was in great pain and had difficulty walking. Since the patient had a history of pancreatic cancer, tumor-marker testing, bone scintigraphy, and dual-energy computed tomography were performed. Although the tumor-marker levels were normal, dual-energy computed tomography and bone scintigraphy revealed fresh compression fractures of the L1 and L3 vertebrae. In addition, dual-energy computed tomography material-discrimination analysis suggested high fat density in the L2 vertebral body. The patient had received approximately 30 Gy radiation to the L2 vertebral body for her pancreatic cancer, which resulted in fatty myelination in the bone. The diagnosis of fatty myelination is made on T1-weighted magnetic resonance images; however, diagnosis remains challenging because of the difficulty in assessing bone morphology on magnetic resonance images. Moreover, some patients are not candidates for magnetic resonance imaging. Dual-energy computed tomography-based material-discrimination analysis can visually depict changes in the bone marrow, and is a valuable diagnostic tool owing to its simplicity.

Assessment of myocardial viability in patients with myocardial infarction is critical to identify residual ischemic tissue in areas of reduced function and to determine the need for revascularization. We present the case of an 80-year-old man with chest pain and a history of hypertension. Initial evaluation revealed abnormal electrocardiogram findings, and subsequent studies suggested chronic anteroseptal myocardial infarction with reduced cardiac function. Dual-energy cardiac computed tomography was performed to evaluate the coronary arteries and myocardium. Late iodine enhancement images obtained by dual-energy computed tomography showed mixed plaques and severe proximal left anterior descending artery stenosis. Conventional late iodine enhancement imaging was inconclusive, prompting extracellular volume fraction analysis using iodine density imaging. Extracellular volume fraction assessment indicated viable anterior myocardium, leading to successful coronary revascularization. Follow-up demonstrated improved wall motion and ejection fraction. Our study highlights the utility of late iodine enhancement with dual-energy computed tomography in assessing myocardial viability as a noninvasive alternative to magnetic resonance imaging, particularly in patients with contraindications to magnetic resonance imaging. This approach aids in treatment planning, evaluation of efficacy and determination of prognosis in cases of ischemic heart disease.

OBJECTIVE: To assess hepatocellular carcinoma (HCC) risk after sustained virologic response (SVR) through clinical data analyses, including evaluation of liver fibrosis using the extracellular volume fraction (ECV) obtained from dual-energy computed tomography (DECT).
METHODS: Ninety-two patients (52 men and 40 women; mean age, 69.9 years) with hepatitis C virus infection after SVR underwent DECT of the liver (3-minute equilibrium-phase images) between January 2020 and March 2022. The ECV was calculated by measuring iodine density; fibrous markers, including ECV, fibrosis-4 index, aspartate aminotransferase to platelet ratio index, and platelet count, were statistically analyzed (p < 0.05). The risk factors associated with HCC were analyzed using univariate and multivariate logistic regression analyses.
RESULTS: The ECV (26.1 ± 4.6 %) in patients with HCC (n,21) was significantly larger than the ECV (20.7 ± 3.3 %) in patients without HCC (n = 71) (p < 0.001). The cutoff value for the ECV was 24.3 %. The area under the operating characteristic curve of the ECV was 0.857, which was higher than that of the serum fibrosis markers. Older age, SVR achieved with interferon, alpha-fetoprotein level (>5 ng/mL), advanced fibrosis before treatment (>F3), and ECV were associated with HCC according to the univariate analysis. Multivariate analyses showed that ECV was the only factor independently associated with HCC (odds ratio 0.619, 95 % confidence interval 0.482-0.795, p < 0.001).
CONCLUSIONS: Liver fibrosis estimated using ECV can be a predictive marker in patients with HCC after SVR.

BACKGROUND: Spinal gout (SG) is a rare condition. So far, a limited number of cases have been reported. Herein, we reported a single case of a 42-year-old male patient with SG involving the cervicothoracic and lumbar spine who underwent cervicothoracic segmental surgery.
METHODS: The patient presented to the hospital with neck pain and limb weakness lasting for one month. He had a history of gout for more than 10 years. Clinical and imaging findings indicated bone and joint tophus erosion, and the patient underwent standard tophi excision and internal fixation with a nail-and-rod system. Histopathological examination suggested gout-like lesions. After the operation, the patient\'s spinal nerve symptoms disappeared, and muscle strength gradually returned to normal. The patient maintained a low-purine diet and was recommended to engage in healthy exercises. The patient recovered well.
CONCLUSIONS: Clinicians should highly suspect SG when patients with chronic gout presented with low back pain and neurological symptoms. Early decompression and debridement surgery are important to relieve neurological symptoms and prevent severe secondary neurological deficits.

Axial gout is an atypical presentation of gout caused by monosodium urate deposition in the axial skeleton. Spinal gout presents nonspecifically and can be a difficult diagnosis. The diagnosis of gout is a clinical one, with imaging and labs providing supporting evidence. Current imaging modalities such as magnetic resonance, computed tomography, and X-ray can be nonspecific and lead to invasive procedures for diagnosis. Dual-energy computed tomography allows clear visualization of urate collection and is a valuable tool to make a confident diagnosis of spinal gout. Here, we present a case of a man with longstanding severe gout in which dual-energy computed tomography played a key role in diagnosis.

UNASSIGNED: Gouty tophi are relatively simple to diagnose because they almost always occur in patients with persistent hyperuricemia. Treatment typically consists mainly of oral medication, and surgical intervention is necessary for only a small number of patients.
UNASSIGNED: We present a case of 66-year-old Japanese man presented with a painful gouty tophus diagnosed by dual-energy computed tomography in the right foot without hyperuricemia that had gradually increased in size over the past 20 years. The tophus was removed and the patient\'s plantar pain disappeared after surgery and there was no recurrence.
UNASSIGNED: We obtained a favorable outcome through surgical intervention for a gouty tophus of the foot diagnosed by dual-energy computed tomography in a patient without hyperuricemia. Our experience suggests that proactive surgical removal of gouty tophi should be considered for symptomatic cases and to prevent further joint destruction.

This study reports systematic longitudinal pathophysiology of lung parenchymal and vascular effects of asymptomatic COVID-19 pneumonia in a young, healthy never-smoking male. Inspiratory and expiratory noncontrast along with contrast dual-energy computed tomography (DECT) scans of the chest were performed at baseline on the day of acute COVID-19 diagnosis (day 0), and across a 90-day period. Despite normal vital signs and pulmonary function tests on the day of diagnosis, the CT scans and corresponding quantification metrics detected abnormalities in parenchymal expansion based on image registration, ground-glass (GGO) texture (inflammation) as well as DECT-derived pulmonary blood volume (PBV). Follow-up scans on day 30 showed improvement in the lung parenchymal mechanics as well as reduced GGO and improved PBV distribution. Improvements in lung PBV continued until day 90. However, the heterogeneity of parenchymal mechanics and texture-derived GGO increased on days 60 and 90. We highlight that even asymptomatic COVID-19 infection with unremarkable vital signs and pulmonary function tests can have measurable effects on lung parenchymal mechanics and vascular pathophysiology, which may follow apparently different clinical courses. For this asymptomatic subject, post COVID-19 regional mechanics demonstrated persistent increased heterogeneity concomitant with return of elevated GGOs, despite early improvements in vascular derangement.NEW & NOTEWORTHY We characterized the temporal changes of lung parenchyma and microvascular pathophysiology from COVID-19 infection in an asymptomatic young, healthy nonsmoking male using dual-energy CT. Lung parenchymal mechanics and microvascular disease followed different clinical courses. Heterogeneous perfused blood volume became more uniform on follow-up visits up to 90 days. However, post COVID-19 mechanical heterogeneity of the lung parenchyma increased after apparent improvements in vascular abnormalities, even with normal spirometric indices.

The aim of this case report is to show the capability of cardiac computed tomography (CT) in combination with dual-energy CT (DECT) delayed myocardial enhancement to support diagnostic decision making in the complicated differential diagnosis of true versus false left ventricle (LV) aneurysm, as well as provide additional information that can influence overall patient outcome. We present a 71-year-old obese patient with metabolic syndrome, stable chronic coronary syndrome with three-vessel disease, and recent chest discomfort. His coronary angiogram showed no significant coronary artery stenosis, but suspicion of LV apical pseudoaneurysm was expressed. Neither transthoracic nor transesophageal echocardiography was able to dismiss this suspicion. Consequently, coronary CT angiography (CCTA) followed by DECT delayed myocardial enhancement was performed. Findings on CCTA and DECT confirmed the diagnosis of a true aneurysm. Moreover, fibrotic changes within the hypertrophic myocardium were visualized. This finding will influence further patient therapy as well as the outcome. DECT delayed myocardial enhancement can be an important complementary tool for distinguishing true versus false LV aneurysms. Moreover, it can provide additional information for making complex diagnose. Adding DECT delayed myocardial enhancement to CCTA can replace cardiac magnetic resonance imaging evaluation in certain settings.

Magnetic resonance imaging (MRI) is degraded by metal-implant-induced artifacts when used for the diagnostic assessment of vertebral compression fractures in patients with instrumented spinal fusion. Dual-energy computed tomography (DECT) offers a promising supplementary imaging tool in these patients. This case report describes an 85-year-old woman who presented with a suspected acute vertebral fracture after long posterior lumbar interbody fusion. This is the first report of a vertebral fracture that showed bone marrow edema on DECT; however, edema was missed by an MRI STIR sequence owing to metal artifacts. Bone marrow assessment using DECT is less susceptible to metal artifacts than MRI, resulting in improved visualization of vertebral edema in the vicinity of fused vertebral bodies.