Multiplanar Reformatted Images Research Articles

Quality assessment of expedited AI generated reformatted images for ED acquired CT abdomen and pelvis imaging.

Retrospectively compare image quality, radiologist diagnostic confidence, and time for images to reach PACS for contrast enhanced abdominopelvic CT examinations created on the scanner console by technologists versus those generated automatically by thin-client artificial intelligence (AI) mechanisms. A retrospective PACS search identified adults who underwent an emergency department contrast-enhanced abdominopelvic CT in 07/2022 (Console Cohort) and 07/2023 (Server Cohort). Coronal and sagittal multiplanar reformatted images (MPR) were created by AI software in the Server cohort. Time to completion of MPR images was compared using 2-sample t-tests for all patients in both cohorts. Two radiologists qualitatively assessed image quality and diagnostic confidence on 5-point Likert scales for 50 consecutive examinations from each cohort. Additionally, they assessed for acute abdominopelvic findings. Continuous variables and qualitative scores were compared with the Mann-Whitney U test. A p < .05 indicated statistical significance. Mean[SD] time to exam completion in PACS was 8.7[11.1] minutes in the Console cohort (n = 728) and 4.6[6.6] minutes in the Server cohort (n = 892), p < .001. 50 examinations in the Console Cohort (28 women 22 men, 51[19] years) and Server cohort (27 women 23 men, 57[19] years) were included for radiologist review. Age, sex, CTDlvol, and DLP were not statistically different between the cohorts (all p > .05). There was no significant difference in image quality or diagnostic confidence for either reader when comparing the Console and Server cohorts (all p > .05). Examinations utilizing AI generated MPRs on a thin-client architecture were completed approximately 50% faster than those utilizing reconstructions generated at the console with no statistical difference in diagnostic confidence or image quality.

Age Estimation by Machine Learning and CT-Multiplanar Reformation of Cranial Sutures in Northern Chinese Han Adults.

To establish age estimation models of northern Chinese Han adults using cranial suture images obtained by CT and multiplanar reformation (MPR), and to explore the applicability of cranial suture closure rule in age estimation of northern Chinese Han population. The head CT samples of 132 northern Chinese Han adults aged 29-80 years were retrospectively collected. Volume reconstruction (VR) and MPR were performed on the skull, and 160 cranial suture tomography images were generated for each sample. Then the MPR images of cranial sutures were scored according to the closure grading criteria, and the mean closure grades of sagittal suture, coronal sutures (both left and right) and lambdoid sutures (both left and right) were calculated respectively. Finally taking the above grades as independent variables, the linear regression model and four machine learning models for age estimation (gradient boosting regression, support vector regression, decision tree regression and Bayesian ridge regression) were established for northern Chinese Han adults age estimation. The accuracy of each model was evaluated. Each cranial suture closure grade was positively correlated with age and the correlation of sagittal suture was the highest. All four machine learning models had higher age estimation accuracy than linear regression model. The support vector regression model had the highest accuracy among the machine learning models with a mean absolute error of 9.542 years. The combination of skull CT-MPR and machine learning model can be used for age estimation in northern Chinese Han adults, but it is still necessary to combine with other adult age estimation indicators in forensic practice.

Computed tomographic measures of renomegaly vary among dogs with different types of congenital portosystemic shunts.

Renomegaly has been reported in dogs with congenital portosystemic shunts (PSS). However, no study has objectively evaluated the degree of renomegaly in dogs with different types of PSS. The purpose of this retrospective, analytical, cross-sectional study was to determine kidney size (renal length-to-L2 vertebral body ratio; RL/L2 ratio) using CT in dogs with different types of PSS and correlate with clinical information. A medical record search for dogs with a PSS diagnosed using CT between 2016 and 2020 was conducted. Breed, age, sex, body weight, and biochemistry results were recorded. Kidney and L2 vertebral body lengths were measured using multiplanar reformatted CT images, and the RL/L2 ratio was calculated. Dogs were categorized into four groups based on PSS morphology for comparisons: intrahepatic (IH; n=19), extrahepatic portocaval (EHPC; n=20), extrahepatic portoazygos (EHPA; n=7), or extrahepatic portophrenic (EHPP, n=7). The RL/L2 ratio (mean±SD) was largest in IH (3.55±0.38) and EHPC (3.55±0.38), followed by EHPP (3.10±0.23), and EHPA (2.78±0.18). RL/L2 ratio was significantly larger in EHPC and IH (vs. EHPA and EHPP [P<.01]). Significant correlations between kidney size and creatinine, alkaline phosphatase, albumin, total protein, and ammonia were present. Renomegaly was observed in 86.8% of dogs with PSS overall, but it was uncommon in dogs with EHPA and less common in dogs with EHPP, as these two groups showed clinical signs later in life, made evident by older age at presentation. The authors suggest that the severity of hepatic dysfunction and the shunted blood volume may influence the development of renomegaly in dogs with PSS.

Limited Axial Interpretation of Coronary CT Angiography in the Emergency Department Setting

PurposeIncorporating coronary CT angiographic (CCTA) imaging into emergency department (ED) workflows has been limited by the need for 24/7 real-time postprocessing. The aim of this study was to determine whether interpretation of transaxial CCTA images alone (limited axial interpretation [LI]) is noninferior to interpretation of combined transaxial and multiplanar reformation images (full interpretation [FI]) in assessing patients with acute chest pain in the ED. MethodsCCTA examinations from 74 patients were evaluated by two radiologists, one without dedicated CCTA training and one with basic CCTA experience. Each examination was evaluated three times in separate sessions, once by LI and twice by FI, in random order. Nineteen coronary artery segments were rated as having significant stenoses (≥50%) or not. Interreader agreement was assessed using Cohen’s κ statistic. The primary analysis was whether the accuracy of LI for detecting significant stenosis was noninferior to that of FI at the patient level (margin = −10%). Secondary analyses included similar analyses of sensitivity and specificity, at both the patient and vessel levels. ResultsInterreader agreement for significant stenosis was good for both LI and FI (κ = 0.72 vs 0.70, P = .74). Average accuracy for significant stenosis at the patient level was 90.5% for LI and 91.9% for FI, with a difference of −1.4%. The accuracy of LI was noninferior to FI, because the confidence interval did not include the noninferiority margin. Noninferiority was also found for patient-level sensitivity and for accuracy, sensitivity, and specificity at the vessel level. ConclusionsLI of the coronary arteries using transaxial CCTA images may be sufficient for the detection of significant coronary artery disease in the ED setting.

Computed tomography in skull base fractures in infants and young children

Aim of the study is to show the possibilities of multiplanar reformation and 3D reconstructions of computed tomography in the diagnosis of skull base fractures in young children.&#x0D; Materials and methods. In one thousand three hundred thirty four children under 3 years of age with traumatic brain injury (TBI) CT was performed on a 128-slice Philips Ingenuity CT scanner; in 707 (53%) in the first 6 hours, in 254 (19%) — after 6 hours, but during the first 24 hours, in 205 (15%) children within 3 days and in 168 (13%) children later on 3 days after injury. Scanning of the area of interest (head + cervical spine) was made with the maximum possible reduction in parameters to minimize the radiation dose. Contrast was not used in children from 0 to 3 years of age with TBI. Post-processing included isotropic multi-planar reformatted (MPR) and 3D images.&#x0D; Results. Of the 1334 children examined, 730 were boys and 604 were girls. In 448 (33.58%) children, fractures of the skull bones were diagnosed, in 366 (81.7%) of them, fractures were combined with intracranial injuries. Fractures of the skull base were in 83 (18.52%) of 448 children. In 65% (n = 54) of cases, basal fractures were combined with fractures of the temporal bones, 31.5% &#x0D; (n = 17) of these children had liquorrhea. Fractures of the anterior fossa (12% of the total number of fractures of the base of the skull) of the base of the skull or fronto-basal fractures were accompanied by additional fractures of the orbits and/or other bones of the facial skull in 56.6% of cases. Fractures of the middle cranial fossa were diagnosed in 54 (65%) children. Fractures of the posterior cranial fossa were found in 19 (23%) of 83 children. In addition to fractures of the bones of the base of the skull, 32 (38.6%) children were diagnosed with fractures of the bones of the vault and intracranial injuries.&#x0D; Conclusion. The use of multiplanar reformation and 3D reconstruction increased the sensitivity and specificity of diagnosing skull base fractures in children compared to conventional axial CT. The essential advantages of using 3D reconstruction are the availability of the technique, the absence of additional scanning time and radiation exposure.

Visualization and quantification of coconut using advanced computed tomography postprocessing technology.

Computed tomography (CT) is a non-invasive examination tool that is widely used in medicine. In this study, we explored its value in visualizing and quantifying coconut. Twelve coconuts were scanned using CT for three months. Axial CT images of the coconuts were obtained using a dual-source CT scanner. In postprocessing process, various three-dimensional models were created by volume rendering (VR), and the plane sections of different angles were obtained through multiplanar reformation (MPR). The morphological parameters and the CT values of the exocarp, mesocarp, endocarp, embryo, bud, solid endosperm, liquid endosperm, and coconut apple were measured. The analysis of variances was used for temporal repeated measures and linear and non-linear regressions were used to analyze the relationship between the data. The MPR images and VR models provide excellent visualization of the different structures of the coconut. The statistical results showed that the weight of coconut and liquid endosperm volume decreased significantly during the three months, while the CT value of coconut apple decreased slightly. We observed a complete germination of a coconut, its data showed a significant negative correlation between the CT value of the bud and the liquid endosperm volume (y = -2.6955x + 244.91; R2 = 0.9859), and a strong positive correlation between the height and CT value of the bud (y = 1.9576 ln(x) -2.1655; R2 = 0.9691). CT technology can be used for visualization and quantitative analysis of the internal structure of the coconut, and some morphological changes and composition changes of the coconut during the germination process were observed during the three-month experiment. Therefore, CT is a potential tool for analyzing coconuts.

Standardized multi-planar reformation improves the reliability of the assessment of the anterolateral ligament in ACL-deficient knees.

The anterolateral ligament (ALL) is an important structure for controlling anterolateral rotatory stability of the knee. Its assessment, however, is difficult using standardized MRI images. The goal of this study was to assess the reliability of judging the integrity of the ALL on multi-planar reformatted (MPR) MRI images and on standard coronal reformatted (SCR) MRI images in knees with an anterior cruciate ligament (ACL) rupture. Forty-eight patients (14 females, 34 males, 30 ± 6years (mean age ± standard deviation)) with acute ACL ruptures (< 2 weeks) and no additional knee injuries (except segond fractures)were included. Images were assessed by two independent raters twice with at least a 2-week interval in between. The assessment was first performed on SCR images and thereafter on MPR images. Images were judged for assessability of the ALL and then the integrity of the ALL was rated. Depending on rater and read, the ALL was judged as "torn" in between 5 (10.4%) and 11 (22.9%) patients out of 48 patients on SCR images. On MRP images, the ALL was judged as "torn" in between 5 (10.4%) and 6 (12.5%) patients out of 48 patients, depending on rater and read. Inter- and intra-rater reliability for the assessment of the ALL using MPR images was "substantial" to "almost perfect". Inter- and intra-rater reliability for the assessment using SCR was "fair" to "substantial". MPR images should be used when assessing the integrity of the ALL. Assessment quality is independent of patient positioning during MRI acquisition and the ALL can be displayed in full length on one image. Level III.

Investigation of the Relationship between Right Coronary Artery-Aorta Angle and Coronary Artery Disease and Associated Risk Factors.

At the level of the left coronary artery tree, there is evidence showing an association between bifurcation angle and coronary artery disease (CAD), and this motivated us to explore similar associations at the level of the right coronary artery (RCA). The purpose of this study was to determine whether there is a relationship between RCA-aorta angle and CAD and age, sex, body mass index, smoking status, hypertension, and high blood cholesterol. The coronary computed tomography angiography datasets and CAD risk factor checklists of 250 patients were retrospectively reviewed, with RCA-aorta angles measured via multiplanar reformation images. Independent t-tests were used to compare mean RCA-aorta angle measurements between groups, correlations between continuous variables were assessed using Pearson and Spearman correlations, and a general linear model was used to adjust for potentially confounding variables. Coronary angle measurements were conducted by two independent assessors with very strong intraclass correlation (r=0.999, p<0.001). A significantly smaller mean RCA-aorta angle was observed in the CAD group (79.07 ± 24.88°) compared to the normal group (92.08 ± 19.51°, p=0.001), in smokers (76.63 ± 22.94°) compared to non-smokers (85.25 ± 23.84°, p=0.016), and a narrow RCA-aorta angle was negatively correlated with BMI (r=-0.174, p=0.010). This study suggests a relationship between narrow RCA-aorta angles and CAD, smoking, and increasing BMI.

MR microneurography of human peripheral fascicles using a clinical 3T MR scanner

Background and purposeKnowledge of nerve fascicular structures is essential for managing peripheral nerve disorders. This study aimed to investigate the feasibility of z-axis high-resolution magnetic resonance (MR) microneurography (zH-MRMN) in displaying the three-dimensional structures of tibial nerve fascicles in vivo using a 3T MR scanner. Materials and methodsTwelve volunteers underwent z-axis conventional-resolution MR microneurography (zC-MRMN) and zH-MRMN of tibial nerves. The visibility scores of the nerve fascicles (VSNFs) on axial zC-MRMN images and axial zH-MRMN multiplanar reformation (MPR) images were compared. The nerve fascicle appearances on the longitudinal zH-MRMN MPR images were described. ResultsIn the nerve segments whose long axes were perpendicular to the imaging planes of both zC-MRMN and zH-MRMN, the VSNFs were not significantly different between the axial images of the two modalities (P = 0.083). In the nerve segments whose long axes were not perpendicular to the imaging planes of zC-MRMN, the VSNFs on the axial zC-MRMN images were significantly lower than those on the axial zH-MRMN MPR images that were angled perpendicular to the long axis of the tibial nerve (P < 0.001). ConclusionsThe longitudinal zH-MRMN MPR images clearly displayed the changing features of the intraneural fascicles as well as the gross morphology of the tibial nerves. zH-MRMN can clearly delineate the topography of the tibial nerve fascicles in vivo through use of a 3T MR scanner.

3D computed tomography intravascular endoscopy.

Using coronary computed tomography angiography (CCTA), coronary plaques can be characterized based on both their morphology and composition. Coronary plaques are generally assessed on 2D axial and multiplanar reformatted images. Nevertheless, these visualization tools are limited to observing extraluminal changes in the coronary artery. The presence of plaques prevents them from providing a visual representation of the intraluminal coronary wall. Since its invention in 2000, coronary fly-through or virtual angioscopy (VA) has been extensively studied. However, its application was limited because it required an optimal CT scan and time-consuming post-processing. In recent years, advances in post-processing software have made construction of VA easier, but until recently the quality of the images was insufficient for most patients. Using 3D intravascular endoscopy (3DIE) visualization, we present various intraluminal appearances of the coronary wall and plaque in relation to various types of plaque.

Abstract 12348: High-Risk Low-Density Non-Calcified Plaque Morphology

Hypothesis The morphology of low-density non-calcified coronary plaque is associated with acute coronary syndrome (ACS) and culprit lesion precursors Methods: This was a post-hoc analysis of the multicenter ICONIC study. A subset of 94 patients suspected of coronary artery disease (CAD) underwent coronary CT angiography imaging (CCTA) with subsequent follow-up for the occurrence of the first ACS event were selected. At the time of ACS, the culprit lesion was adjudicated by invasive coronary angiography cardiologists blinded to the CCTA. Quantitative CT was performed by a validated software as a service (Cleerly Labs, Cleerly, Inc., Denver, CO). A level-III reader used multiplanar reformation (MPR) images from this analysis to qualitatively assess individual collections of low-density non-calcified (LDNC) plaques (-189 to 30 HU). The degree of embedded LDNC plaque (DELP) was the amount a LDNC plaque was surrounded by non-calcified plaque. DELP was categorized as 90, 180, 270, and 360. LDNC plaque shape was categorized as crescent, round, lobular, or bean-shaped. DELP and shape were qualitatively assessed using the cross-sectional MPR image with the greatest LDNC plaque area. LDNC plaques with &gt;270 DELP and round or bean-shaped were considered high-risk plaque (HRP) morphology. Results: ACS occurred in 64 patients. 247 LDNC plaques were analyzed. Patients without and with ACS had, on average 0.40±0.86 and 1.02±1.21 (p-value = 0.014) LDNC plaques with HRP morphology. The proportional hazard ratio associating the presence of one or more HRP morphology plaques with ACS was 2.03 (1.19, 3.48; p-value = 0.009), after controlling for diameter stenosis, age, sex, and family history of CAD. The odds ratio of the association of HRP morphology with culprit lesion precursors was 10.93 (3.77, 31.71; p-value &lt;0.001), after controlling for diameter stenosis, age, sex, and family history of CAD. Conclusion HRP morphology may improve the stratification of patients at risk for ACS.

Abstract 11224: Anatomical Characteristics of Myocardial Bridging and Its Impact on Myocardial Ischemia in Patients With Nonobstructive Coronary Artery Disease

Introduction. Epicardial coronary arteries running through the myocardium (myocardial bridges: MBs) are compressed during myocardial contraction and may be involved in myocardial ischemia. However, the anatomical characteristics of MBs and their impact on myocardial ischemia have not been well characterized. Methods. We included 626 patients who underwent coronary artery computed tomography to evaluate ischemic signs and/or symptoms (mean age 66±13 years, 32% males). Curved multiplanar reformation images were used to assess MBs' presence, length, and thickness. In patients with positive noninvasive stress testing (NST), we compared the frequency and anatomical characteristics of MBs between patients with obstructive coronary arteries (OCA defined as &gt;50% stenosis in main branches) and those with nonobstructive coronary arteries (INOCA). Results. MBs were found in 176 patients (28%), of which 45% were superficial (≤2 mm), 54% were deep (2-5 mm), and 1% were very deep (&gt;5 mm) MBs (mean MB thickness 2.2±0.9 mm). The mean MB length was 18.2±5.7 mm with 14% long MBs (≥25 mm). Ninety-four out of 202 patients undergoing NST presented positive results, 62 of whom had OCA and 32 had INOCA. MBs were more frequently observed in patients with INOCA than in those with OCA (63% vs. 39%, P=0.03) (Figure A). Interestingly, INOCA patients tended to have longer MBs than those with OCA (20.7±6.0 mm vs. 17.6±5.4 mm, P=0.08), whereas MB thickness was not different between the two groups (2.3±0.7 vs. 2.0±0.6, P=0.19) (Figure B). Conclusion. Longer MBs may significantly impact myocardial perfusion, potentially producing positive results on stress tests in patients with INOCA.

Evaluation of Prevalence and Features of Coronary Artery Anomalies using Multidetector-row Computed Tomography

Aim: To evaluate the course, origin and termination of coronary artery anomalies in subjects demonstrating various symptoms and undergoing multidetector CT coronary angiography for evaluation of coronary disease. Study Design: Retrospective study Place and duration: Ch.Pervaiz Elahi Institute of Cardiology Multan from January 2021 to January 2022. Methodology: The study included patients who were referred to the radiology department because of suspicion of coronary artery disease. The data of these patients were reviewed for the course and origin of coronary artery anomalies. A 64-slice scanner was used for MDCT coronary angiography. At the start of acquisition contrast arriving coronary arteries were synchronised using the bolus tracking technique. The whole heart was imaged during apnea using 80-90ml iodinated contrast material administered intravenously. Coronary arteries were evaluated using 3-D and multiplanar reformatted images Results: Total of 600 patients who were referred for MDCT coronary angiography. The subjects underwent screening because of various risk factors, chest pain, or similar symptoms. Coronary artery anomalies were diagnosed in 21 out of 600 (3.5%) patients, whose mean age was 52.6±10.8 years and 504 (84%) were male. 3(14%) patients had high take-off of RCA (right coronary right) and 4(19%) of LMCA (left main coronary artery). In 5(24%) patients left circumflex artery (LCx) and left anterior descending artery (LAD) originated separately from the left sinus of Valsalva (LSV). In 3(14%) patients RCA originated from the opposite sinus of Valsalva.RCA anomaly in 1 patient had a malignant course. Conclusion: The study shows that evaluation of coronary artery anomalies can viably be done using CT. Right diagnosis and treatment planning are based upon an understanding of the clinical significance and CT characteristics of different CAAs. Keywords: Coronary artery angiography, MDCT, prevalence

Right auricle aneurysm in dogs can be detected with multidetector-row CT and presents with varying morphology.

Right auricle aneurysm (RAA) has been reported to be a rare congenital or acquired condition in dogs, however published CT characteristics are limited to a small number of cases. The aim of this 13-year, single-center, retrospective, cross-sectional study was to describe the prevalence and appearance of RAA in a larger group of dogs. Reports of 10,886 dogs that underwent thoracic CT examination for various reasons were reviewed. Computed tomographic data of dogs with presumed RAA (based on published imaging characteristics) were retrieved from the archive. Oblique multiplanar reformatted images were used to record RAA site, shape, and dimensions (neck, maximum height and width). Patients' sex, age, and body weight were evaluated for any association with the presence of RAA. Presumed RAA was detected in 23/10,886 dogs having thoracic CT in the selected period of time (prevalence 0.21%). Three RAA phenotypes were described: diffuse saccular dilation in 19 of 23 dogs, focal saccular dilation in three of 23 dogs, and fusiform in one of 23 dogs. The bodyweights of dogs with presumed RAA were significantly lower than those of the remaining 10836 dogs without RAA (median 8kg [IQR 5; range 37.6] and median 16kg [IQR 23; range 116.9] respectively; P<0.003. Female sex was also significantly associated with RAA (P=0.03). Findings indicated that RAA has a low prevalence in dogs, can be detected with CT, can be present in asymptomatic dogs, and can have varying appearances. In this sample of dogs, female sex and low body weight were significantly associated with RAA.

Is it feasible to measure pulmonary vein data using volume rendering images?

Pulmonary vein (PV) data are commonly measured on multiplanar image reformation (MPR) images and volume rendering (VR) images. To compared and analyze the advantages and disadvantages of PV data based on VR images and MPR images. A total of 94 patients with atrial fibrillation (AF) with imaging data were included in the study. The respective image postprocessing time and the three surgical interventionists' preferences for the two images were recorded. A paired t-test or chi-square test was used to compare their difference, and P < 0.05 was considered statistically significant. There was no statistically significant difference between the data values including the maximal and minimal ostial diameters of the left superior PV (LSPV), the left inferior PV (LIPV), the right superior PV (RSPV), and the right inferior PV (RIPV) obtained by VR and MPR images (P > 0.05). Yet, the mean postprocessing time of VR images (15.10 ± 3.05 min) was shorter compared to MPR images (16.54 ± 2.60 min) (t = 22.84, P < 0.05). All three surgical interventionists preferred VR images (accounted for 85.1%, 86.2%, and 84.0%, respectively), and there was no statistical difference in the degree of image preference among the three (chi-square = 0.596, P = 0.963). PV data measurement could be performed on both VR and MRP images; however, the data on VR images were more intuitive and more accessible for interventional surgeons.

Dual-layer spectral detector CT for contrast agent concentration, dose and injection rate reduction: Utility in imaging of the superior mesenteric artery

PurposeTo investigate the feasibility of contrast agent and injection rate reduction for dual-layer spectral detector computed tomography (SDCT) imaging of the superior mesenteric artery (SMA) using virtual monochromatic image (VMI). MethodsA total of 102 patients who underwent abdominal arterial phase-enhanced SDCT examination due to suspected abdominal diseases were prospectively selected and divided into control group, low concentration/dose groups (groups 370-0.7, 300-1.0, and 300-0.9) and low injection rate groups (groups 2-370 and 2-350). Compared with the control group, low concentration/dose groups and low injection rate groups lowered the concentration/dose or injection rate of the contrast agent to varying degrees. The raw data obtained in each group were reconstructed using hybrid-iterative reconstruction and projection spatial-spectral reconstruction algorithm. The image quality of the SMA in conventional images (CI) and in VMIs40-140 kiloelectron volt (keV) (interval: 10 keV) during the arterial phase was analyzed. Multiplanar reformation images and volume rendering images of the SMA were reconstructed. Image quality objective evaluation indexes included the CT values, contrast-to-noise ratio, signal-to-noise ratio, and diameter of the SMA. The diameter of the SMA was determined by the CT values profile curve and its full width at half maximum. Two doctors independently evaluated the subjective image quality of multiplanar reformation coronal images and volume rendering images according to a 5-point scale. Repeated analysis of variance and Friedman test were used to compare the differences in the objective evaluation indexes and subjective scores between VMIs and CI in the same group. The Dunnett’s t-test or Dunnett’s T3 test and Kruskal-Wallis H-test were used to compare the differences in the objective evaluation indexes and subjective scores between the experimental and control groups. ResultsVMIs of the SMA in each group had the best image quality at 60 keV, and VMI60 keV in each group were better than their respective CI to varying degrees. Although the objective (CT values, contrast-to-noise ratio, and signal-to-noise ratio) and subjective (subjective scores) indexes of CI in the low concentration/dose groups and low injection rate groups were lower than those of CI in the control group to varying degrees, these indexes of VMI60 keV in the low concentration/dose groups and group 2-370 were equal to or even better than the CI in the control group. ConclusionsVMI60 keV using SDCT could effectively reduce the contrast agent load while providing equivalent or better SMA image quality compared with CI obtained using a conventional contrast agent protocol. When the injection rate was lowered to 2.0 ml/s for a high-concentration contrast agent (370 mgI/ml), the SMA image quality at VMI60 keV was comparable with that of the CI in the control group.

Evaluation of a deep learning model on coronary CT angiography for automatic stenosis detection

PurposeThe purpose of this study was to evaluate a deep-learning model (DLM) for classifying coronary arteries on coronary computed tomography -angiography (CCTA) using the Coronary Artery Disease-Reporting and Data System (CAD-RADS). Materials and methodsThe DLM was trained with 10,800 curved multiplanar reformatted (cMPR) CCTA images classified by an expert radiologist using the CAD-RADS. For each of the three main coronary arteries, nine cMPR images 40° apart acquired around each arterial circumference were then classified by the DLM using the highest probability. For the validation set composed of 159 arteries from 53 consecutive patients, the images were read by two senior and two junior readers; consensus of the two seniors was the reference standard. With the DLM, the majority vote for the nine images was used to classify each artery. Three groups (CAD-RADS 0, 1–2, or 3–4–5) and 2 groups CAD-RADS 0–1–2 or 3–4–5 (<50% vs. ≥50% stenosis) were used for comparisons with readers and consensus. Performance of the model and readers was compared to the consensus reading using the intraclass coefficient (ICC) and Cohen's kappa coefficient at the artery and patient levels. ResultsWith the three groups at the artery level, the ICC of the DLM was 0.82 (95% CI: 0.75–0.88) and not significantly different from those of 3/4 readers; accuracy was 81%. With the binary classification, Cohen kappa coefficient of the DLM was 0.85 (95% CI: 0.69–0.94) and not significantly different from that of 3/4 readers; accuracy was 96%. At the patient level, sensitivity and specificity were 93% and 97% respectively, and the negative predictive value was 97%. ConclusionThe DLM detected ≥50% stenoses with performances similar to those achieved by senior radiologists.

Investigation of the Relationship Between Idiopathic Intracranial Hypertension and Superior Semicircular Canal Dehiscence

Purpose: The etiology of superior semicircular canal dehiscence (SSCD) is not yet clear; however, several theories implicate cumulative erosive changes. Here, using thin-section temporal bone CT images, we aimed to investigate the relationship between the bone roof thickness overlying the SSC and idiopathic intracranial hypertension (IIH) which may cause repetitive microtrauma. Materıals and methods: Between January 2017-December 2019, temporal bone CT scans from 18 patients with a diagnosis of IIH, and 21 age- and sex-matched controls were analyzed retrospectively. Multiplanar reformatted images (Pöschl and Stenver) were reconstructed from the scans and the roof thickness of the SSC bone was measured and SSCD was classified in 4 grades. Results: A total of 78 thin-section temporal bone CT scans were evaluated. Although grade-II dehiscence was most frequent in both groups, grade-IV was only observed in both temporal bones of one patient in the IIH group. Grade-III and grade-IV dehiscence rates were significantly higher in the IIH group (p=0.006). There was a significant difference between IIH and control groups in terms of SSC bone roof thickness (p=0.03). Conclusıon: Increased CSF pressure in patients with IIH may cause chronic, progressive, and irreversible damage to the bone that covers the superior semicircular canal, and may play a role as a predisposing factor for SSCD.

Deep-learning image-reconstruction algorithm for dual-energy CT angiography with reduced iodine dose: preliminary results

To evaluate the computed tomography (CT) attenuation values, background noise, arterial depiction, and image quality in whole-body dual-energy CT angiography (DECTA) at 40 keV with a reduced iodine dose using deep-learning image reconstruction (DLIR) and compare them with hybrid iterative reconstruction (IR). Whole-body DECTA with a reduced iodine dose (200 mg iodine/kg) was performed in 22 patients, and DECTA data at 1.25-mm section thickness with 50% overlap were reconstructed at 40 keV using 40% adaptive statistical iterative reconstruction with Veo (hybrid-IR group), and DLIR at medium and high levels (DLIR-M and DLIR-H groups). The CT attenuation values of the thoracic and abdominal aortas and iliac artery and background noise were measured. Arterial depiction and image quality on axial, multiplanar reformatted (MPR), and volume-rendered (VR) images were assessed by two readers. Quantitative and qualitative parameters were compared between the hybrid-IR, DLIR-M, and DLIR-H groups. The vascular CT attenuation values were almost comparable between the three groups (p=0.013-0.97), but the background noise was significantly lower in the DLIR-H group than in the hybrid-IR and DLIR-M groups (p<0.001). The arterial depictions on axial and MPR images and in almost all arteries on VR images were comparable (p=0.14-1). The image quality of axial, MPR, and VR images was significantly better in the DLIR-H group (p<0.001-0.015). DLIR significantly reduced background noise and improved image quality in DECTA at 40 keV compared with hybrid-IR, while maintaining the arterial depiction in almost all arteries.

Reliability of Anatomic Bony Landmark Localization of the ACL Femoral Footprint Using 3D MRI.

Background:Nonanatomic placement of anterior cruciate ligament (ACL) grafts is a leading cause of ACL graft failure. Three-dimensional (3D) magnetic resonance imaging (MRI) femoral footprint localization could enhance planning for an ACL graft's position.Purpose:To determine the intra- and interobserver reliability of measurements of the ACL femoral footprint position and size obtained from 3D MRI scans.Study Design:Cohort study; Level of evidence, 3.Methods:A total of 41 patients with complete ACL tears were recruited between November 2014 and May 2016. Preoperatively, a coronal-oblique proton-density fast spin echo 3D acquisition of the contralateral uninjured knee was obtained along the plane of the ACL using a 1.5T MRI scanner. ACL footprint parameters were obtained independently by 2 musculoskeletal radiologists (observers A and B). The distal and anterior positions of the center of the footprint were measured relative to the apex of the deep cartilage at the posteromedial aspect of the lateral femoral condyle, and the surface area of the ACL femoral footprint was approximated from multiplanar reformatted images. After 1 month, the measurements were repeated. Intraclass correlation coefficients (ICCs) were calculated to assess for intra- and interobserver reliability. Bland-Altman plots were produced to screen for potential systematic bias in measurement and to calculate limits of agreement.Results:The ICCs for intraobserver reliability of the ACL femoral distal and anterior footprint coordinates were 0.75 and 0.78, respectively, for observer A. For observer B, they were 0.75 and 0.74, respectively. The ICCs for interobserver reliability were 0.75 and 0.85 for the distal and anterior coordinates, respectively. Bland-Altman plots demonstrated no significant systematic bias. For surface area measurements, the intraobserver ICCs were 0.37 and 0.62 for observers A and B, respectively. The interobserver reliability was 0.60. Observer B consistently measured the footprints as slightly larger versus observer A (1.19 ± 0.27 vs 1 ± 0.22 cm2, respectively; P < .001).Conclusion:Locating the center of the anatomic footprint of the ACL with 3D MRI showed substantial intra- and interobserver agreement. Interobserver agreement for the femoral footprint surface area was fair to moderate.