Postmortem computed tomographic features in the diagnosis of drowning: a comparison of fresh water and salt water drowning cases Whereas in FWDCs, a significantly larger volume and lower density of fluid in the paranasal sinuses (P = 0.0195 and P = 0.0104, respectively), lower density of fluid in the central airways (P = 0.0077), lower stomach content density (P = 0.0216), lower density in the left atrium (P = 0.0029), and a difference of density between the atria (P = 0.0019) were observed.

Liver imaging reporting and data system (LI-RADS) v2018: comparison between computed tomography and gadoxetic acid-enhanced magnetic resonance imaging Abstract Purpose To determine the consistency of major hepatocellular carcinoma (HCC) features between CT and MRI based on Liver Imaging Reporting and Data System (LI-RADS) v2018 and to investigate the additional value on gadoxetic acid-enhanced MRI. Materials and methods Patients who underwent dynamic CT and gadoxetic acid-enhanced MRI within 1 month were investigated. Two radiologists evaluated the presence of major HCC features and categorized observations using LI-RADS v2018 algorithm. In addition, each observation was recorded as hyper-, iso-, or hypo-intensity on hepatobiliary-phase (HBP) images. Results Sixty-one patients with 110 observations were identified. Among 88 observations classified as LR-3, 4 or 5, arterial phase hyper-enhancement and washout appearance showed higher frequencies on CT than on MRI (75.0% vs. 58.0%, P < 0.001, and 60.2% vs. 44.3%, P = 0.014, respectively). Of the 59 LR-3 observations categorized on MRI, 70.0% of observations with hypo-intensity on HBP images were HCCs, whereas 89.5% of observations with iso- or hyper-intensity on HBP images were non-HCCs (P < 0.001) Conclusion The frequencies of arterial phase hyper-enhancement and washout appearances were higher on CT than on gadoxetic acid-enhanced MRI. For LR-3 observations, adding the hepatobiliary-phase hypo-intensity to major features improved the diagnostic performance of MRI in distinguishing HCCs from non-HCC lesions.

CT and MR imaging findings of non-neoplastic cystic lesions of the parotid gland Abstract A variety of neoplastic and non-neoplastic lesions of the parotid gland can present with a predominantly cystic architecture, and although radiologists frequently encounter cystic parotid tumors, other non-neoplastic lesions should also be included in the differential diagnoses of cystic parotid lesions. Non-neoplastic cystic lesions are usually classified as either congenital/acquired cystic lesions or inflammatory/infectious lesions. Adequate knowledge about these rare conditions is essential for appropriate diagnosis and optimal treatment strategy. This review article describes CT and MR imaging features of non-neoplastic cystic lesions of the parotid gland and provides helpful suggestions on the differential diagnoses for cystic parotid lesions.

The opacity of mineral ion-loaded bead (DC beads ® ) on low-keV monochromatic images from dual energy CT and T1-weighted gradient-echo MRI Abstract Purpose To evaluate the opacity of DC beads® (DCB) loaded with mineral ions on low-keV monochromatic images from dual energy computed tomography (DECT) and T1-weighted gradient-echo (T1-GRE) MRI. Materials and methods Fe2+ or Ca2+-loaded DCBs were prepared by mixing DCBs in 100 mM FeSO4 or CaSO4 solution and scanned by DECT from 10 min to 27 h after mixing. The Hounsfield units (HUs) of sedimented DCBs on 40-keV monochromatic images were measured. Next, we mixed DCBs in 100, 10, 5 and 1 mM FeSO4 solutions, and scanned these solutions from 15 to 120 min after mixing using a 3 T MR scanner. The signal–noise ratios (SNRs) of sedimented DCBs on T1-GRE were measured. Venous blood was scanned to compare with DCBs. Results The CT values of DCBs in FeSO4 and CaCl2 solutions gradually increased, and were 113.3 and 43.1 HU at 27 h, respectively; that of blood was 17.8 HU. The SNR of DCB in 1 mM FeSO4 solution increased and achieved equilibrium at 120 min, and was 120.5 and higher than in the other FeSO4 solutions. The SNR of blood was 49.7. Conclusion Optimally Fe2+-loaded DCBs can be discriminated from venous blood on 40-keV monochromatic images from DECT and T1-GRE.

Effect of renal denervation procedure on left ventricular mass, myocardial strain and diastolic function by CMR on a 12-month follow-up Abstract Purpose To investigate the effects of renal denervation (RDN) on left ventricular (LV) mass, myocardial strain and diastolic function in patients with treatment-resistant arterial hypertension by cardiac magnet resonance imaging on a 12-month follow-up. Materials and methods Sixteen patients (38% female) were examined before and 12 months after RDN. LV morphology and strain were analyzed. Diastolic function was determined by early (EPFR) and atrial peak filling rates (APFR) derived from differential volume–time-curve analysis. Clinical visits included 24-h ambulant blood pressure monitoring (ABPM). Results Twelve months after RDN LV mass decreased from 80 ± 21 g/m2 to 74 ± 20 g/m2 (P < 0.05). Global radial (35 ± 12% vs. 41 ± 10%, P < 0.05) and longitudinal strain improved (− 15 ± 4% vs. − 17 ± 3%, P < 0.05). Global circumferential strain (− 16 ± 5% vs. − 18 ± 4%, P = 0.12) remained unchanged. The parameter of diastolic LV function PFRR (EPFR/APFR) improved following RDN (0.9 ± 0.4 vs. 1.1 ± 0.5, P < 0.05). Individual changes of LV mass were associated with an increase of EPFR (r = − 0.54, P < 0.05) and a reduction of APFR by trend (r = 0.45, P = 0.08). Systolic ABPM showed a decrease by trend (152 mmHg vs. 148 mmHg, P = 0.08). Conclusions After RDN we observed a reduction of LV mass, improvement of global strain and diastolic function.

Influence of virtual monochromatic spectral image at different energy levels on motion artifact correction in dual-energy spectral coronary CT angiography Abstract Purpose To investigate the influence of virtual monochromatic spectral (VMS) CT images at different energy levels on the effectiveness of a motion correction technique (SSF) in dual-energy Spectral coronary CT angiography (CCTA). Materials and methods 29 cases suspected of or diagnosed with coronary artery disease underwent Spectral CCTA using a prospective ECG triggering with 250 ms padding time. SSF was applied to the determined least-motion phase to generate 6 additional sets of VMS images with energy levels from 40 to 100 keV. CT value and standard deviation (SD) in the aortic root and epicardial adipose tissue were measured. Image quality of the RCA, LAD and LCX was evaluated on a per-vessel basis in each patient. Two reviewers evaluated the artery using the score of the segment. Results The low energy VMS images increased CT value and image noise compared with higher-energy VMS images, except 90 keV and 100 keV. The CNR of 40–70 keV were higher than those of 80–100 keV (P < 0.05). The image quality scores for images at 50–80 keV were higher than those of 40, 90, and 100 keV (P < 0.05), and the VMS image quality at 50 keV and 60 keV with SSF was the highest. Conclusion SSF can effectively reduce the motion artifacts when coronary vessels have suitable contrast enhancement which can be achieved by adjusting energy levels of VMS images.

Assessment of angiogenesis in rabbit orthotropic liver tumors using three-dimensional dynamic contrast-enhanced ultrasound compared with two-dimensional DCE-US Abstract Objectives To evaluate quantitative three-dimensional (3D) dynamic contrast-enhanced ultrasound (DCE-US) in the assessment of tumor angiogenesis using an orthotropic liver tumor model. Methods Nine New Zealand white rabbits with liver orthotropic VX2 tumors were established and imaged by two-dimensional (2D) and 3D DCE-US after SonoVue® bolus injections. The intraclass correlation coefficients of perfusion parameters, including peak intensity (PI), mean transit time, time to peak, and area under the curve, were calculated based on time-intensity curve. The percentage area of microvascular (PAMV) and the expression of vascular endothelial growth factor (VEGF) were both evaluated by immunohistochemical analysis and weighted by the tumor activity area ratio. Correlations between quantitative and histologic parameters were analyzed. Results The reproducibility of 3D DCE-US quantitative parameters was excellent (ICC 0.91–0.99); but only PI showed high reproducibility (ICC 0.97) in 2D. None of the parameters of quantitative 2D DCE-US were significantly correlated with weighted PAMV or VEGF. For 3D DCE-US, there was a positive correlation between PI and weighted PAMV (r = 0.74, P = 0.04) as well as VEGF (r = 0.79, P = 0.02). Conclusion Quantitative parameters of 3D DCE-US show feasibility, higher reproducibility and accuracy for the assessment of tumor angiogenesis using an orthotropic liver tumor model compared with 2D DCE-US.

Whole-tumor histogram analysis of DWI and QSI for differentiating between meningioma and schwannoma: a pilot study Abstract Purpose To investigate whether whole-tumor histogram analyses of diffusivity measurements derived from q-space imaging (QSI) improves the differentiation between meningioma and schwannoma. Materials and methods Fifteen extra-axial tumors (11 meningiomas and 4 schwannomas) with MR examinations from April 2011 to May 2013 were included. Three-dimensional regions of interest (ROI) encompassed the whole tumor, including cystic areas. Histogram analyses of mean displacement (MD) derived from QSI and apparent diffusion coefficient (ADC) for the ROI were performed at mean, the five percentiles of MDn and ADCn (n = 5, 25, 50, 75, 95th), kurtosis, and skewness. To determine the diagnostic ability of MDn and ADCn, we also compared the area under the curve (AUC) on receiver operating characteristic (ROC) analysis. Results Histogram analyses revealed significant differences between meningioma and schwannoma in MD75, ADC25, ADC50, ADC75, and kurtosis of ADC. The ROC analysis of kurtosis of ADC and MD75 resulted in an AUC of 1.0 and 0.96, respectively. There were no significant differences between the AUC of MD75 and that of kurtosis of ADC (p = 0.41). Conclusion The histogram analyses of MD and ADC derived from QSI were both equally useful in differentiating between intracranial meningioma and schwannoma.

CT gastrography “wall-carving technique” of gastric cancer: impact of contrast enhancement based on layer depth Abstract Purpose Wall-carving technique (WC) is a special volume rendering technique of three-dimensional CT gastrography that can illustrate the enhancement of gastric wall at an arbitrary depth. We conducted the present study to evaluate the impact of contrast enhancement based on layer depth on WC of gastric cancer and to correlate them with pathological findings. Methods The subjects of this retrospective study consisted of 36 patients with advanced gastric cancer (22 men, 14 women; age range, 39–90 years; median, 67 years) who underwent contrast-enhanced CT before surgery. WC images of arterial phase were divided into first and second layer. Two radiologists in consensus evaluated the contrast enhancement of WC images for each layer and correlated with pathologic factors. Results Twenty-six (72%) of the gastric cancers showed a well-enhanced lesion in the first layer at the arterial phase on WC images, and 18 (50%) showed a well-enhanced lesion in the second layer. The study of second layers showed that the well-enhanced group had significantly more cases of differentiated type histology and intermediate stroma than the normally to poorly enhanced group (p = 0.008 and 0.0026). Conclusion The contrast enhancement on WC of gastric cancer showed a significant relationship with pathological factors based on layer depth.

Comparison of magnetization transfer contrast of conventional and simultaneous multislice turbo spin echo acquisitions focusing on excitation time interval Abstract Purpose Image contrast differs between conventional multislice turbo spin echo (conventional TSE) and multiband turbo spin echo (SMS-TSE). Difference in time interval between excitations for adjacent slices (SETI) might cause this difference. This study aimed to evaluate the influence of SETI on MT effect for conventional TSE and compare conventional TSE with SMS-TSE in this respect. Materials and methods Three different agar concentration phantoms were scanned with conventional TSE by adjusting SETI and TR. Signal change for different SETI was evaluated using Pearson’s correlation analysis. SMS-TSE was acquired by changing TR similarly. Three human volunteers were scanned with similar settings to evaluate reproducibility of the phantom results in human brain. Results In conventional TSE, shorter SETI induced larger signal reduction. Longer TR and higher agar concentration emphasized this characteristic. Significant linear correlation (P < 0.05) was found in the major cases. The SMS-TSE signal intensity in each TR and phantom was smaller than the assumable levels in conventional TSE when the slices were simultaneously excited. Similar characteristic was observed in human brain. Conclusion Shorter SETI results in larger MT effect in conventional TSE. The contrast change in SMS-TSE was larger than the supposable level from simultaneous excitation, which needs consideration in clinics.