Journal of Computer Assisted Tomography最新文献

Objective: The second-generation motion correction algorithm, Snapshot Freeze 2.0 (SSF2), is designed to suppress coronary artery motion in cardiac CT angiography. This study aimed to evaluate whether SSF2 improves unenhanced CT images and to compare the coronary artery calcium score (CACS) values reconstructed with and without SSF2.

Methods: One hundred nineteen patients with coronary artery calcium (CACS >0) were enrolled in this study. Unenhanced CT for CACS was performed with a phase window limited to 75% of the R-R interval, using 120 kVp and automatic tube current modulation. CACS values were measured on images with and without SSF2, and absolute differences were calculated. Two radiologists assessed the overall image quality, focusing on coronary artery motion, using a 4-point scale (1=uninterpretable, 4=no motion artifacts).

Results: The absolute differences in CACS for patients with heart rates of 60-95 bpm (n=85) were larger than those with heart rates of up to 59 bpm (n=21) or above 95 bpm (n=13) (median: 10.6, range: 0.1 to 171.2; median: 9.3, range: 0.8 to 31.8; median: 6.0, range: 1.6 to 43.4, respectively). In patients with heart rates of 60 to 95 bpm, SSF2 improved image quality scores (P<0.001); however, for heart rates of up to 59 bpm or above 95 bpm, the improvements were not significant (P=0.18 and 0.10, respectively).

Conclusions: SSF2 reduces motion artifacts in the coronary arteries on unenhanced CT and significantly alters the CACS values. A more accurate calcification assessment is anticipated with SSF2, especially in patients with heart rates of 60 to 95 bpm.

Objective: Pulmonary air trapping is critical for diagnosing and prognostication of various lung diseases. Expiratory CT imaging serves as an accessible method to assess air trapping, which correlates with small airway disease outcomes. Air trapping manifests as mosaic attenuation on inspiratory chest CT that is difficult for visual estimation. The primary aim of this study was to develop an automated tool to quantify mosaic attenuation on inspiratory CT and air trapping on paired expiratory CT. Secondary aims included comparing CT-derived parameters with PFT measurements and dyspnea scores.

Methods: This retrospective analysis of noncontrast chest CTs from 2 academic hospitals was conducted between January 1, 2018, and December 31, 2019. Patients with paired inspiratory and expiratory CT chest scans and PFTs performed on the same day were included. A chest radiologist manually annotated lung parenchyma in a reference cohort. Several histogram-based metrics were computed from lung parenchymal CT values, with the maximum peak position showing the strongest correlation with manually determined thresholds. This threshold, derived from the histogram peak, was applied in the adaptive thresholding process to quantify mosaic attenuation and air trapping.

Results: We analyzed 267 patients (65.5% female, median age 68). Most exhibited normal physiological patterns (44.0%). Patients with elevated residual volume (RV) by PFTs (28.1%) had significantly higher inspiratory CT mosaic attenuation (1629.6 vs. 1311.5 mL, P<0.01) and expiratory CT air trapping volumes (1413.7 vs. 886.2 mL, P<0.01). Correlation analyses demonstrated strong relationships between CT-derived mosaic attenuation and air trapping measures and RV. The correlation with PFT parameters was even stronger in subgroup analyses in patients with obstructive PFT patterns. These models had good predictive ability for an abnormal RV (AUC of 0.92, sensitivity of 72.4%, and specificity of 92.0%) and clinical utility based on good correlation with the mMRC dyspnea score (r=0.71; 95% CI: 0.65-0.77).

Conclusions: This automated adaptive thresholding on inspiratory and expiratory chest CT scans showed a high correlation of lung volume and air trapping parameters with PFTs, revealing that measures of lung function have a complex interplay with air trapping.

Objective: Whole-brain computed tomography perfusion (CTP) imaging is a dose-intensive imaging technique. We aimed to investigate optimal scanning protocol of the whole-brain CTP using a 320-detector row CT in reducing radiation dose for acute ischemic stroke (AIS) patients.

Methods: This study included 54 consecutive AIS patients who underwent whole-brain CTP on a 320-detector row CT scanner. We evaluated the penumbra and ischemic core volumes of CTPfull, CTP3/4, and CTP1/2, created using full, 3/4 and 1/2 scanning data, respectively. Wilcoxon signed-rank test, Spearman correlation coefficient, and Bland-Altman analysis were used for the statistical analysis. In addition, hypothetical treatment decisions based on the DEFUSE-3 criteria were also evaluated to determine whether there were any differences in the treatment decisions when using reduced sampling data (CTP3/4 and CTP1/2) compared with full data to assess its clinical efficacy.

Results: The penumbra and ischemic core median volumes on CTPfull, CTP3/4, and CTP1/2 were 111.5 mL [interquartile range (IQR): 52.0-173.0] and 5.5 mL (IQR: 0 to 24.0), 106.5 mL (IQR: 47.0 to 170.0) and 6.5 mL (IQR: 0 to 24.0), 106.5 mL (IQR: 48.0 to 178.0), and 5.5 mL (IQR: 0 to 23.0), respectively. There were no significant differences in penumbra (P>0.05) and ischemic core (P>0.05) volumes between CTPfull, CTP3/4, and CTP1/2. Spearman correlation analysis showed significant correlations between CTPfull and CTP3/4 and CTP1/2 for both penumbra (r=0.989 to 0.998, P<0.001) and ischemic core (r=0.997 to 0.982, P<0.001) volumes. The hypothetical treatment strategies determined using reduced sampling data (CTP3/4, and CTP1/2) were largely consistent compared with those using CTPfull.

Conclusions: The use of half-scanning data for the whole-brain CTP image with a 320-detector row CT may help to lower the radiation exposure to AIS patients without significant loss of perfusion information.

It is estimated that Generation Z will outnumber the next closest generation, the Millennials (born between 1981 and 1996), by 2040.Only a small number of them are currently in residency training; however, they have already entered the workforce in other professions. Many companies have studied Generation Z and have recognized major differences compared with older generations. Medical professionals can learn from the work already done to adjust for a smooth transition to medical training and postgraduate practice.

Purpose: This study aimed to evaluate the clinical value of the fat attenuation index (FAI) of pericoronary adipose tissue (PCAT) and fractional flow reserve derived from coronary computed tomography angiography (CT-FFR) in predicting coronary revascularization.

Methods: Patients with known or suspected acute coronary syndrome (ACS) who underwent coronary computed tomography angiography (CCTA) and subsequent invasive coronary angiography (ICA) were screened. FAI, lesion-specific CT-FFR, and distal-tip CT-FFR were analyzed by core laboratories blinded to patient management. Per-vessel and per-patient logistic univariable and multivariable analyses were performed to predict revascularization. Three multivariable logistic regression models were compared, with ROC curves generated for each model and AUCs compared. Incremental predictive value between models 2 and 3 was also measured using continuous net reclassification improvement (NRI).

Results: A total of 94 patients who received CCTA followed by ICA were identified and analyzed; 282 vessels were included. Overall, 54 (57.4%) patients with 72 (25.5%) vessels underwent revascularization. Lesion-specific CT-FFR, FAI, and significant stenosis were significantly associated with revascularization in both univariable and multivariable analyses. Lesion-specific CT-FFR, FAI, and significant stenosis were independent predictors of coronary revascularization. In the per-vessel analysis, those with 2 or 3 risk factors had a markedly higher revascularization rate [50 of 69 (72.5%) vs. 22 of 213 (10.3%); P < 0.001]. In the per-patient analysis, those with 2 or 3 risk factors had a markedly higher revascularization rate [35 of 42 (83.3%) vs. 19 of 52 (36.5%); P < 0.001]. The continuous net reclassification improvement (NRI) for the addition of FAI and CT-FFR to standard CCTA analysis (model 3 over model 2) was 0.273 (95% CI, 0.166-0.379, P < 0.0001).

Conclusions: This study demonstrated the application value of CT-FFR and FAI in predicting coronary revascularization in patients with documented ACS. CT-FFR and FAI obtained from quantitative CCTA improved the prediction of future revascularization. These parameters can potentially identify patients likely to receive revascularization upon referral for cardiac catheterization. However, the clinical use of FAI may be limited by the lack of standardization in PCAT values and the absence of a clear established cutoff for clinical relevance.

Purpose: Magnetic resonance cholangiopancreatography (MRCP) may assist in the workup of infantile cholestasis as nonvisualization of the biliary tree is seen with biliary atresia (BA). However, this finding can also be seen with other causes of infantile cholestasis. The purpose of this study is to differentiate BA from other causes of infantile cholestasis using a classification tool integrating MRCP-based radiomics and clinical signatures in patients with nonvisualization of the extrahepatic biliary tree on MRCP.

Methods: Data from infants with cholestasis due to BA, cytomegalovirus infection, or idiopathic neonatal hepatitis (INH) from 2 sites was collected. Radiomics features from MRCP images were selected using Spearman and LASSO methods, followed by applying the optimal machine learning model to develop a radiomics signature. Clinical factors showing significant differences between BA and non-BA groups in training cohort were used to develop a clinical signature using the model. A nomogram model incorporating the signatures was developed. The nomogram model and signatures' performance were assessed using the area under the curve (AUC), accuracy, sensitivity, specificity, precision, and F1 score. The DeLong test, decision curve analysis (DCA), calibration curves, and the Hosmer-Lemeshow test were utilized to evaluate the nomogram model.

Results: The training cohort consisted of 112 cases (62 BA and 50 non-BA) from site 1, while the external validation cohort included 35 cases (20 BA and 15 non-BA) from site 2. After screening, 2 clinical factors and 8 radiomics features were included. The signatures were fitted using the K-Nearest Neighbors model. The nomogram model showed an AUC of 0.981 in the training cohort and 0.913 in the external validation cohort, significantly outperforming both the signatures in the training cohort and the clinical signature in the external validation cohort, as confirmed by the DeLong test. The DCA indicated the clinical utility of the model. The Calibration curves and the Hosmer-Lemeshow test confirmed the model's adequate fit.

Conclusion: The nomogram model may hold clinical utility. In our cohorts, it was effective for identifying BA among cases with infantile cholestasis attributed to BA, cytomegalovirus infection, or INH in scenarios where the extrahepatic biliary system is not visualized on MRCP.

Objective: To assess agreement between abdominal ultrasound and MRI for the detection of focal liver lesions and manifestations of portal hypertension in patients with Fontan circulation.

Materials and methods: To perform this single-center, retrospective study, we identified patients with Fontan circulation who underwent clinical abdominal ultrasound and MRI examinations within ±12 months between January 1, 2018 and June 30, 2023. Imaging reports were reviewed for the presence of liver lesions (specifically noting lesions >1 cm and radiologist-indicated suspicious lesions), features of portal hypertension (ie, presence of ascites and spleen length), abnormal liver contour, and liver stiffness. Intermodality agreement, sensitivity and specificity of ultrasound relative to MRI, and Spearman correlation were used to compare ultrasound and MRI measurements. Follow-up of detected lesions was also performed using electronic health records.

Results: There were 58 patients included. Agreement between MRI and ultrasound for the findings of Fontan-associated liver disease (FALD) was as follows: presence of a liver lesion of any size [k = 0.20 (95% CI: 0.08 to 0.32)], presence of a liver lesion >1 cm [k = 0.43 (95% CI: 0.18 to 0.68)], radiologist-indicated suspicious liver lesion(s) [k = 0.07 (95% CI: -0.13 to 0.27)], presence of ascites [k = 0.57 (95% CI: 0.32 to 0.81)], abnormal liver contour [k = 0.31 (95% CI: 0.03 to 0.59)], and spleen length [intraclass correlation coefficient = 0.81 (95% CI: 0.58 to 0.92)]. Sensitivity and specificity of ultrasound using MRI as the reference standard were as follows: 34% (95% CI: 20% to 50%) and 100% (95% CI: 77% to 100%) for the presence of a liver lesion of any size, and 39% (95% CI: 17% to 64%) and 98% (95% CI: 87% to 100%) for the presence of a liver lesion >1 cm. There was a poor correlation between ultrasound and MRI liver stiffness measurements [rho = 0.22 (95% CI: -0.14 to 0.53); P = 0.23]. Of 44 patients with liver lesions, 3 (6.8%) had biopsy-confirmed hepatocellular neoplasms, including 2 adenomas and 1 hepatocellular carcinoma. All 3 lesions were detected by both MRI and ultrasound.

Conclusions: There is poor to fair agreement between ultrasound and MRI for detecting manifestations of FALD, with ultrasound having poor sensitivity compared with MRI. While ultrasound detected all 3 clinically important liver lesions in our study, our results raise questions about whether ultrasound is an appropriate screening tool for FALD in patients post-Fontan.

Objective: Portable computed tomography (CT) scanners allow bedside brain imaging in critically ill patients without the risks of transport, but historically these scanners have demonstrated image quality inferior to that of fixed scanners. In this study, the quality of head CT examinations using a newer-generation portable scanner, the On.site, was compared with that of an older-generation portable scanner, the CereTom, as well as to that of fixed CT scanners.

Methods: Head CT examinations performed on the On.site scanner were retrospectively compared with those conducted on the same patient within 24 hours using the CereTom scanner or fixed scanners. A similar analysis was also carried out between the CereTom and fixed scanners. Three neuroradiologists rated the images qualitatively. Quantitative assessment included signal difference to noise ratio (SdNR) and noise magnitude in the cerebrospinal fluid, bone, and pons.

Results: The On.site scanner had higher image quality scores than the CereTom scanner ( P <0.001) and was 10 to 20 times less likely to produce subpar images. Mean noise in the pons was slightly higher with On.site than with CereTom ( P =0.014). Fixed scanners had higher qualitative scores than the On.site scanner, but there was no significant difference between the scanners in the probability of producing subpar images. The CereTom scanner had significantly lower qualitative scores than fixed scanners, and significantly increased probability of producing subpar and nondiagnostic images ( P <0.001). The SdNR was lower with the On.site scanner than with the fixed scanners ( P <0.001). Noise magnitude measures were higher with On.site than with fixed scanners ( P <0.001 for all).

Conclusions: The On.site scanner had significantly better qualitative image quality than the CereTom scanner and had a much lower probability of producing subpar or nondiagnostic images. Although the On.site scanner had inferior qualitative and quantitative image quality compared with the fixed scanners, there was no significant difference in the probability of producing subpar or nondiagnostic images. This may indicate a decreased need to transport sick patients out of the neurological intensive care unit for imaging in the future.

Objective: This study aims to investigate the diagnostic value of dual-energy computed tomography (DECT)-derived quantitative imaging parameters, including arterial iodine fraction (AIF), extracellular volume fraction (fECV), and iodine washout rate (IWR), in the assessment of liver function grading in patients with cirrhosis, to identify the optimal diagnostic parameters.

Methods: We collected DECT data from 68 patients with cirrhosis and 25 healthy controls at our institution and used the albumin-bilirubin (ALBI) scoring system for liver function grading. DECT images were processed for iodine quantification, and AIF, fECV, and IWR parameters were calculated. The correlation between DECT iodine parameters and ALBI grading was analyzed using the Spearman correlation coefficient; independent-sample t tests or nonparametric Mann-Whitney U tests were used to compare the differences in parameters between the cirrhosis group and the normal control group. The nonparametric Kruskal-Wallis H test was used to compare DECT iodine parameters across different ALBI groups within the cirrhosis cohort. The diagnostic efficacy of the iodine parameters in discriminating different ALBI grades was analyzed using the receiver operating characteristic (ROC) curve.

Results: Significant correlations were observed between AIF, fECV, and IWR with ALBI grades (r=0.873, 0.908, and -0.846, respectively; all P<0.001). In the cirrhosis group, AIF, fECV, and IWR exhibited statistically significant differences across ALBI grades (all P<0.001). The AUC values of fECV for distinguishing Control versus ALBI1+2+3, ALBI1 versus ALBI2+3, and ALBI1+2 versus ALBI3 were 0.955 (0.918 to 0.993), 0.945 (0.900 to 0.994), and 0.974 (0.942 to 1.000), respectively, with corresponding optimal cutoff values of 27.41%, 29.34%, and 35.40%, the diagnostic effect was better than AIF and IWR.

Conclusion: DECT-derived AIF, fECV, and IWR effectively assess liver function in cirrhosis through ALBI grading, with fECV showing superior standalone performance; multiparametric integration enhances diagnostic accuracy.

Objectives: This study aimed to simultaneously evaluate 4D cardiac magnetic resonance (MR)-derived kinetic energy (KE) of intra-left ventricular (LV) blood flow, wall kinetics, and myocardial perfusion under pharmacological stress in patients with coronary artery disease (CAD) using a hybrid PET/MR system.

Methods: Sixty-five patients (mean 68±12 y; male, 53) with CAD who underwent rest-stress 13N-ammonia PET/MR were included. MR acquisition was performed simultaneously during the PET scan to obtain rest-stress 4D flow, and followed by cine MR to measure LV ejection fraction (LVEF) and myocardial strain, including global longitudinal strain (GLS). The maximum KE during the cardiac cycle was calculated and indexed to the end-diastolic LV volume (maxKEi, μJ/mL) at rest and during stress. Perfusion defect, myocardial flow (MBF), and flow reserve (MFR) were assessed through rest-stress PET.

Results: MaxKEi showed a significant correlation with LVEF and GLS for both rest and stress (r=0.3, P=0.01, r=-0.4, P=0.04 for rest LVEF and GLS; r=0.4, P=0.0009, r=-0.4, P=0.003, for stress LVEF and GLS, respectively). Stress maxKEi showed a significant correlation with stress MBF and MFR (r=0.3, P=0.006, and r=0.3, P=0.03, for stress MBF and MFR, respectively).

Conclusion: Noninvasive assessment of 4D flow MR-derived intra-LV KE demonstrated a significant association with wall kinetics and endothelial function under pharmacological stress.