ACTA Radiologica (Test)

Acta Radiologica, Ahead of Print. <br/>BackgroundWe aimed to establish a novel model using a radiomics analysis of magnetic resonance (MR) images for predicting osteoporosis.PurposeTo investigate the effectiveness of a radiomics approach utilizing magnetic resonance imaging (MRI) of the lumbar spine in identifying osteoporosis.Material and MethodsIn this retrospective study, a total of 291 patients who underwent MRI were analyzed. Radiomics features were extracted from the MRI scans of all 1455 lumbar vertebrae, and build the radiomics model based on T2-weighted (T2W), T1-weighted (T1W), and T2W + T1W imaging. The performance of the combined model was assessed using metrics such as the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and accuracy. The AUCs of these models were compared using the DeLong test. Their clinical usefulness was assessed using a decision curve analysis.ResultsT2W, T1W, and T1W + T2W imaging retained 27, 27, and 17 non-zero coefficients, respectively. The AUCS about radiomics scores based on T2W, T1W, and T1W + T2W imaging were 0.894, 0.934, and 0.945, respectively, which all performed better than the clinical model significantly. The rad-signatures based on T1W + T2W imaging, which exhibited a stronger predictive power, were included in the creation of the nomogram for osteoporosis diagnosis, and the AUC was 0.965 (95% confidence interval (CI)=0.944–0.986) in the training cohort and 0.917 (95% CI=0.738–1.000) in the test cohort. The calibration curve indicated that the radiomics nomogram had considerable clinical usefulness in prediction, observation, and decision curve analysis.ConclusionA reliable and powerful tool for identifying osteoporosis can be provided by the nomogram that combines the T1W and T2W imaging radiomics score with clinical risk factors.

Acta Radiologica, Ahead of Print. <br/>BackgroundPercutaneous cholecystostomy (PC) is a therapeutic intervention for acute cholecystitis. The benefits of cholecystostomy have been demonstrated in the medical literature, with up to 90% of acute cholecystitis cases shown to resolve postoperatively, and only 40% of patients subsequently undergoing an interval cholecystectomy.PurposeTo compare the survival outcomes between acute complicated and uncomplicated cholecystitis in patients undergoing PC as an initial intervention, as there is a paucity of evidence in the literature on this perspective.Material and MethodsA retrospective search was conducted of all patients who underwent PC for acute cholecystitis between August 2016 and December 2020 at a tertiary institution. A total of 100 patients were included in this study.ResultsThe outcome, in the form of 30-day mortality, 90-day mortality, being alive after six months, and reintervention, was compared between complicated and uncomplicated cases using the chi-square test or Fisher's exact test. There was no statistically significant difference in any of the compared outcomes. The only variable that showed a statistically significant association with the risk of mortality was acute kidney injury (AKI) at admission. Patients who had stage 1, 2, or 3 AKI had a higher hazard for mortality as compared to patients with no kidney disease.ConclusionOur results demonstrate that PC is a safe and effective procedure. Mortality is not affected by the presence of complications. The results have, however, highlighted the importance of recognizing and treating AKI, an independent risk factor affecting mortality.

Acta Radiologica, Ahead of Print. <br/>BackgroundThe safety and efficacy of mechanical thrombectomy (MT) for proximal large vessel occlusion after acute ischemic stroke (AIS) have been demonstrated. Clinical investigations of endovascular approaches for treating AIS due to M2 occlusions have been ongoing.PurposeTo assess the outcomes of M2 occlusions according to treatment modality and anatomical division.MethodsA total of 113 consecutive M2 occlusions treated with endovascular treatment (EVT) at our tertiary stroke center between January 2019 and December 2022 were retrospectively analyzed. Patients were divided into three groups: mechanical thrombectomy (MT); intravenous thrombolysis plus MT (IVT + MT); and IVT alone. The primary outcomes were good prognosis (mRS = 0–2) and mortality (mRS = 6) on day 90. The secondary outcome was to determine the differences in outcomes between lesions in the superior and inferior branches of M2.ResultsIn total, 55 (48.7%) patients underwent MT. In 42 (37.2%) patients, bridging IVT was performed with MT, and IVT alone was applied in 16 (14.2%) patients. Neither the prognosis at 90 days nor the mortality rate significantly differed among the groups. The outcomes did not significantly differ between occlusions in the superior and inferior branches of M2.ConclusionMT was found to be safe and effective for treating M2 occlusions in this series.

Acta Radiologica, Ahead of Print. <br/>BackgroundEpicardial adipose tissue (EAT) volume is usually measured with ECG-gated computed tomography (CT). Measurement of EAT thickness is a more convenient method; however, it is not clear whether EAT thickness measured with non-gated CT is reliable and at which localization it agrees best with the EAT volume.PurposeTo examine the agreement between ECG-gated EAT volume and non-gated EAT thickness measured from various localizations and to assess the predictive role of EAT thickness for high EAT volume.Material and MethodsEAT thickness was measured at six locations using non-contrast thorax CT and EAT volume was measured using ECG-gated cardiac CT (n = 68). The correlation and agreement (Bland–Altman plots) between the thicknesses and EAT volume were assessed.ResultsEAT thicknesses were significantly correlated with EAT volume (P < 0.001). The highest correlation (r = 0.860) and agreement were observed for the thickness adjacent to the right ventricular free wall. Also, EAT thickness at this location has a strong potential for discriminating high (>125 cm3) EAT volume (area under the ROC curve=0.889, 95% CI=0.801–0.977; P < 0.001). The sensitivity, specificity, and positive and negative predictive values of EAT thickness for high EAT volume were 76.5%, 88.2%, 68.4%, and 91.8%, respectively, for the cutoff value of 5.75 cm; and 47.1%, 100%, 100%, and 85%, respectively, for the cutoff value of 8.10 cm.ConclusionEAT thickness measured on non-gated chest CT adjacent to the right ventricular free wall is a reliable and easy-to-use alternative to the volumetric quantification and has a strong potential to predict high EAT volume.

Acta Radiologica, Ahead of Print. <br/>BackgroundThe grading of adult isocitrate dehydrogenase (IDH)-mutant astrocytomas is a crucial prognostic factor.PurposeTo investigate the value of conventional magnetic resonance imaging (MRI) features and apparent diffusion coefficient (ADC) in the grading of adult IDH-mutant astrocytomas, and to analyze the correlation between ADC and the Ki-67 proliferation index.Material and MethodsThe clinical and MRI data of 82 patients with adult IDH-mutant astrocytoma who underwent surgical resection and molecular genetic testing with IDH and 1p/19q were retrospectively analyzed. The conventional MRI features, ADCmin, ADCmean, and nADC of the tumors were compared using the Kruskal–Wallis single factor ANOVA and chi-square tests. Receiver operating characteristic (ROC) curves were drawn to evaluate conventional MRI and ADC accuracy in differentiating tumor grades. Pearson correlation analysis was performed to determine the correlation between ADC and the Ki-67 proliferation index.ResultsThe difference in enhancement, ADCmin, ADCmean, and nADC among WHO grade 2, 3, and 4 tumors was statistically significant (all P <0.05). ADCmin showed the preferable diagnostic accuracy for grading WHO grade 2 and 3 tumors (AUC=0.724, sensitivity=63.4%, specificity=80%, positive predictive value (PPV)=62.0%; negative predictive value (NPV)=82.5%), and distinguishing grade 3 from grade 4 tumors (AUC=0.764, sensitivity=70%, specificity=76.2%, PPV=75.0%, NPV=71.4%). Enhancement + ADC model showed an optimal predictive accuracy (grade 2 vs. 3: AUC = 0.759; grade 3 vs. 4: AUC = 0.799). The Ki-67 proliferation index was negatively correlated with ADCmin, ADCmean, and nADC (all P <0.05), and positively correlated with tumor grade.ConclusionConventional MRI features and ADC are valuable to predict pathological grading of adult IDH-mutant astrocytomas.

Acta Radiologica, Ahead of Print. <br/>BackgroundDynamic myocardial computed tomography perfusion (CTP) is a novel imaging technique that increases the applicability of CT for cardiac imaging; however, the scanning requires a substantial radiation dose.PurposeTo investigate the feasibility of dose reduction in dynamic CTP by comparing all-heartbeat acquisitions to periodic skipping of heartbeats.Material and MethodsWe retrieved imaging data of 38 dynamic CTP patients and created new datasets with every fourth, third or second beat (Skip1:4, Skip1:3, Skip1:2, respectively) removed. Seven observers evaluated the resulting images and perfusion maps for perfusion deficits. The mean blood flow (MBF) in each of the 16 myocardial segments was compared per skipped-beat level, normalized by the respective MBF for the full dose, and averaged across patients. The number of segments/cases whose MBF was <1.0 mL/g/min were counted.ResultsOut of 608 segments in 38 cases, the total additional number of false-negative (FN) segments over those present in the full-dose acquisitions and the number of additional false-positive cases were shown as acquisition (segment [%], case): Skip1:4: 7 (1.2%, 1); Skip1:3: 12 (2%, 3), and Skip1:2: 5 (0.8%, 2). The variability in quantitative MBF analysis in the repeated analysis for the reference condition resulted in 8 (1.3%) additional FN segments. The normalized results show a comparable MBF across all segments and patients, with relative mean MBFs as 1.02 ± 0.16, 1.03 ± 0.25, and 1.06 ± 0.30 for the Skip1:4, Skip1:3, and Skip1:2 protocols, respectively.ConclusionSkipping every second beat acquisition during dynamic myocardial CTP appears feasible and may result in a radiation dose reduction of 50%. Diagnostic performance does not decrease after removing 50% of time points in dynamic sequence.

Acta Radiologica, Ahead of Print. <br/>BackgroundComputed tomography (CT) radiomics combined with deep transfer learning was used to identify cholesterol and adenomatous gallbladder polyps that have not been well evaluated before surgery.PurposeTo investigate the potential of various machine learning models, incorporating radiomics and deep transfer learning, in predicting the nature of cholesterol and adenomatous gallbladder polyps.Material and MethodsA retrospective analysis was conducted on clinical and imaging data from 100 patients with cholesterol or adenomatous polyps confirmed by surgery and pathology at our hospital between September 2015 and February 2023. Preoperative contrast-enhanced CT radiomics combined with deep learning features were utilized, and t-tests and least absolute shrinkage and selection operator (LASSO) cross-validation were employed for feature selection. Subsequently, 11 machine learning algorithms were utilized to construct prediction models, and the area under the ROC curve (AUC), accuracy, and F1 measure were used to assess model performance, which was validated in a validation group.ResultsThe Logistic algorithm demonstrated the most effective prediction in identifying polyp properties based on 10 radiomics combined with deep learning features, achieving the highest AUC (0.85 in the validation group, 95% confidence interval = 0.68–1.0). In addition, the accuracy (0.83 in the validation group) and F1 measure (0.76 in the validation group) also indicated strong performance.ConclusionThe machine learning radiomics combined with deep learning model based on enhanced CT proves valuable in predicting the characteristics of cholesterol and adenomatous gallbladder polyps. This approach provides a more reliable basis for preoperative diagnosis and treatment of these conditions.

Acta Radiologica, Ahead of Print. <br/>BackgroundPost-contrast T1-Sampling Perfection with Application-optimized Contrasts using different flip angle Evolutions (SPACE) is the preferred 3D T1 spin-echo sequence for evaluating brain metastases, regardless of the prolonged scan time.PurposeTo evaluate the application of accelerated post-contrast T1-SPACE with iterative denoising (ID) for intracranial enhancing lesions in oncologic patients.Material and MethodsFor evaluation of intracranial lesions, 108 patients underwent standard and accelerated T1-SPACE during the same imaging session. Two neuroradiologists evaluated the overall image quality, artifacts, degree of enhancement, mean contrast-to-noise ratiolesion/parenchyma, and number of enhancing lesions for standard and accelerated T1-SPACE without ID.ResultsAlthough there was a significant difference in the overall image quality and mean contrast-to-noise ratiolesion/parenchyma between standard and accelerated T1-SPACE without ID and accelerated SPACE with and without ID, there was no significant difference between standard and accelerated T1-SPACE with ID. Accelerated T1-SPACE showed more artifacts than standard T1-SPACE; however, accelerated T1-SPACE with ID showed significantly fewer artifacts than accelerated T1-SPACE without ID. Accelerated T1-SPACE without ID showed a significantly lower number of enhancing lesions than standard- and accelerated T1-SPACE with ID; however, there was no significant difference between standard and accelerated T1-SPACE with ID, regardless of lesion size.ConclusionAlthough accelerated T1-SPACE markedly decreased the scan time, it showed lower overall image quality and lesion detectability than the standard T1-SPACE. Application of ID to accelerated T1-SPACE resulted in comparable overall image quality and detection of enhancing lesions in brain parenchyma as standard T1-SPACE. Accelerated T1-SPACE with ID may be a promising replacement for standard T1-SPACE.

Acta Radiologica, Ahead of Print. <br/>The crista terminalis is an anatomical structure localized on the posterolateral wall of the right atrium (RA). We performed a systematic review of the literature and meta-analysis concerning cases of unusual prominent crista terminalis mimicking RA mass. Moreover, we described the differential diagnosis of cardiac masses with the use of echocardiography, computed tomography, and cardiac magnetic resonance (CMR). We also emphasize the potential importance of this structure in electrophysiological procedures, including its role in exaggerated arrhythmias. Prominent crista terminalis may be a potential obstacle during invasive cardiac procedures or catheter ablation target. In analyzed cases, the crista terminalis was often erroneously interpreted as pathologic and at first confused with a thrombus or tumor during transthoracic echocardiography examination. The correct final diagnoses were mostly made with used transesophageal echocardiography or CMR. The most important imaging findings suggestive of prominent crista terminalis rather than tumor were a similar echogenicity/intensity with adjacent myocardium, the location on posterolateral wall of the RA, the phasic change in size, and no enhancement after contrast injection. We describe up to date and detailed imaging features for the differential diagnostics of selected intracardiac masses using various imaging techniques, including multimodality cardiac imaging. Familiarity with the anatomy and the imaging findings of the prominent crista terminalis will reduce misdiagnosis and avoid additional tests and unwarranted clinical interventions, while in patients considered for invasive cardiac procedures it might increase their efficacy and safety.

Acta Radiologica, Ahead of Print. <br/>BackgroundNon-invasive imaging methods are still lacking for evaluating bone changes in chronic kidney diseases (CKD).PurposeTo investigate the feasibility of chest CT radiomics in evaluating bone changes caused by CKD.Material and MethodsIn total, 75 patients with stage 1 CKD (CKD1) and 75 with stage 5 CKD (CKD5) were assessed using the chest CT radiomics method. Radiomics features of bone were obtained using 3D Slicer software and were then compared between CKD1 and CKD5 cases. The methods of maximum correlation minimum redundancy (mRMR) and least absolute shrinkage and selection operator (LASSO) were used to establish a prediction model to determine CKD. The receiver operating characteristic (ROC) curve was used to determine the performance of the model.ResultsCases of CKD1 and CKD5 differed in 40 radiomics features (P <0.05). Using the mRMR and LASSO methods, five features were finally selected to establish a predication model. The area under the receiver operating characteristic curve of the model in the determination of CKD1 and CKD5 was 0.903 and 0.854, respectively, for the training and validation cohorts.ConclusionChest CT radiomics is feasible in evaluating bone changes caused by CKD.