Dual-Energy Computed Tomography in Stroke Imaging : Value of a New Image Acquisition Technique for Ischemia Detection after Mechanical Thrombectomy.

OBJECTIVE: To assess if a new dual-energy computed tomography (DECT) technique enables an improved visualization of ischemic brain tissue after mechanical thrombectomy in acute stroke patients. MATERIAL AND METHODS: The DECT head scans with a new sequential technique (TwinSpiral DECT) were performed in 41 patients with ischemic stroke after endovascular thrombectomy and were retrospectively included. Standard mixed and virtual non-contrast (VNC) images were reconstructed. Infarct visibility and image noise were assessed qualitatively by two readers using a 4-point Likert scale. Quantitative Hounsfield units (HU) were used to assess density differences of ischemic brain tissue versus healthy tissue on the non-affected contralateral hemisphere. RESULTS: Infarct visibility was significantly better in VNC compared to mixed images for both readers R1 (VNC: median 1 (range 1-3), mixed: median 2 (range 1-4), p < 0.05) and R2 (VNC: median 2 (range 1-3), mixed: 2 (range 1-4), p < 0.05). Qualitative image noise was significantly higher in VNC compared to mixed images for both readers R1 (VNC: median 3, mixed: 2) and R2 (VNC: median 2, mixed: 1, p < 0.05, each). Mean HU were significantly different between the infarcted tissue and the reference healthy brain tissue on the contralateral hemisphere in VNC (infarct 24 ± 3) and mixed images (infarct 33 ± 5, p < 0.05, each). The mean HU difference between ischemia and reference in VNC images (mean 8 ± 3) was significantly higher (p < 0.05) compared to the mean HU difference in mixed images (mean 5 ± 4). CONCLUSION: TwinSpiral DECT allows an improved qualitative and quantitative visualization of ischemic brain tissue in ischemic stroke patients after endovascular treatment.

A Novel Dual-Energy CT Method for Detection and Differentiation of Intracerebral Hemorrhage From Contrast Extravasation in Stroke Patients After Endovascular Thrombectomy : Feasibility and First Results.

PURPOSE: Dual-energy computed tomography (DECT) has been shown to be able to differentiate between intracranial hemorrhage (ICH) and extravasation of iodinated contrast media (contrast staining [CS]). TwinSpiral DECT is a recently introduced technique, which allows image acquisition at two different energy levels in two consecutive spiral scans. The aim of this study was to evaluate the feasibility and accuracy of TwinSpiral DECT to distinguish between ICH and CS after endovascular thrombectomy (EVT) in patients with acute ischemic stroke. METHODS: This retrospective single-center study conducted between November 2019 and July 2020 included non-contrast TwinSpiral DECT scans (tube voltages 80 and 150Sn kVp) of 39 ischemic stroke patients (18 females, 21 males, mean age 69 ± 11 years) within 48-72 h after endovascular thrombectomy. Parenchymal hyperdensity was assessed for the presence of ICH or/and CS by two board certified and fellowship-trained, blinded and independent neuroradiologists using standard mixed images and virtual non-contrast (VNC) images with corresponding iodine maps from TwinSpiral DECT. Follow-up examinations (FU; CT or MRI) were used as a standard of reference. Sensitivity, specificity, and accuracy for the detection of ICH as well as the inter-reader agreement were calculated. RESULTS: Parenchymal hyperdensities were detected in 17/39 (44%) patients. Using DECT, they were classified by both readers as ICH in 9 (53%), CS in 8 (47%), and mixture of both in 6 (35%) cases with excellent agreement (κ = 0.81, P < 0.0001). The sensitivity, specificity, and accuracy for the detection of ICH in DECT was 90% (95% confidence interval [CI]: 84-96%), 100% (95% CI 94-100%) and 95% (95% CI 89-100%), and in mixed images 90% (95% CI 84-96%), 86% (95% CI 80-92%) and 88% (95% CI 82-94%), respectively. Inter-reader agreement for detecting ICH on DECT compared to the mixed images was κ = 1.00 (P < 0.0001) vs. κ = 0.51 (P = 0.034). CONCLUSION: TwinSpiral DECT demonstrates high accuracy and excellent specificity for differentiating ICH from CS in patients after mechanical thrombectomy due to acute ischemic stroke, and improves inter-reader agreement for detecting ICH compared to the standard mixed images.

Cranial Intraosseous Meningiomas: CT and MRI Findings.

AIM: To evaluate computed tomography (CT) and magnetic resonance imaging (MRI) findings of cranial intraosseous meningiomas (IOMs). MATERIAL AND METHODS: This study included ten patients (six females and four males) with IOMs who underwent cranial CT and/ or MRI examinations during May 2009?June 2018. Lesions were classified based on the following locations: the sphenoid ridge, the calvarial convexity, other skull base bones, and the sphenoid ridge + calvarial extension. Bony extension, contour irregularity or radial bone spiculation, bony changes (hyperostotic, lytic, or mixed patterns), dural calcification, cerebral edema, and the presence of soft tissue were evaluated. RESULTS: A total of eleven IOMs were identified in ten patients. The age of patients was 46?80 (mean: 55.30 ± 9.84) years. Five of the lesions were located in the sphenoid ridge + calvarium, three in the sphenoid ridge, two in the skull base, and one in the calvarial convexity. Seven lesions exhibited radial bone spiculation. Moreover, nine lesions exhibited hyperostotic CT pattern; while, two exhibited a mixed pattern. Three IOMs were accompanied with dural calcification, and peritumoral edema was observed in six IOMs. CONCLUSION: IOMs are predominantly low-grade tumors, commonly located in the periorbital area and often accompanied by soft tissue components and dural infiltrations. They most commonly lead to radial bone spiculation and bone expansion. Patients primarily have single lesions but may occasionally have multiple ones.

Hydatid cyst presented as a subcutaneous thigh mass.

Hydatid disease is an endemic zoonosis, and patients are generally from cattle- and sheep-raising regions of the world, such as Central Europe, the Mediterranean, the Middle East, China, South America, Australia, New Zealand, South Africa, and Russia (Lewall and McCorkell in Radiology 155:773-775, 1985). Furthermore, hydatid cyst is a disease of immigrants in non-endemic countries and in developed countries (Stojkovic et al. in PLoS Negl Trop Dis 6:e1880, 2012). The most common affected organs are liver and lungs. Hydatid cyst located in the subcutaneous tissue constitutes an extremely rare manifestation of the hydatid disease (Savulescu et al. in Chir Buchar Rom 1990 105:419-422, 2010). In this study, we report an uncommon case of hydatid cyst that developed in the subcutaneous tissue of the right thigh of a patient with ultrasound, computed tomography, and magnetic resonance imaging findings.

Value of Ultrasound Elastography in the Differential Diagnosis of Cervical Lymph Nodes: A Comparative Study With B-mode and Color Doppler Sonography.

OBJECTIVES: The purpose of this study was to determine the usefulness of ultrasound elastography in the evaluation of enlarged cervical lymph nodes in comparison with B-mode and color Doppler sonography. METHODS: A total of 220 lymph nodes in 168 consecutive patients who were referred for sonography of the neck were included in this study. B-mode sonograms were evaluated according to short-axis diameter, long-to-short-axis ratio, hilum, echogenicity, and microcalcification. For color Doppler sonography, 5 different patterns were defined according to vascularity. Elastographic patterns of the lesions were categorized to 5 main types. The mean strain index values were calculated for all lymph nodes. Histopathologic findings, clinical and laboratory data, and imaging findings were used as reference standards for the diagnosis of benign and malignant lymph nodes. RESULTS: Of the 220 lymph nodes, 69.5% were diagnosed as benign, and 30.5% were diagnosed as malignant. The sensitivity, specificity, and accuracy of B-mode sonography were 97.0%, 31.4%, and 51.3%, respectively; the values were 76.1%, 82.4%, and 80.5% for color Doppler sonography and 82.1%, 56.2%, and 64.1% for elastography. The strain index cutoff value for the differentiation of benign and malignant lymph nodes was accepted as 1.7. The sensitivity, specificity, and accuracy of the strain index were 71.6%, 76.5%, and 75.0%. CONCLUSIONS: Ultrasound elastography adds no additional value to combined B-mode and color Doppler sonography for differentiation of benign and malignant cervical lymph nodes.