Late gadolinium enhanced cardiac MR derived radiomics approach for predicting all-cause mortality in cardiac amyloidosis: a multicenter study.

OBJECTIVES: To evaluate the prognostic value of radiomics features based on late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) images in patients with cardiac amyloidosis (CA). METHODS: This retrospective study included 120 CA patients undergoing CMR at three institutions. Radiomics features were extracted from global and three different segments (base, mid-ventricular, and apex) of left ventricular (LV) on short-axis LGE images. Primary endpoint was all-cause mortality. The predictive performance of the radiomics features and semi-quantitative and quantitative LGE parameters were compared by ROC. The AUC was used to observe whether Rad-score had an incremental value for clinical stage. The Kaplan-Meier curve was used to further stratify the risk of CA patients. RESULTS: During a median follow-up of 12.9 months, 30% (40/120) patients died. There was no significant difference in the predictive performance of the radiomics model in different LV sections in the validation set (AUCs of the global, basal, middle, and apical radiomics model were 0.75, 0.77, 0.76, and 0.77, respectively; all p > 0.05). The predictive performance of the Rad-score of the base-LV was better than that of the LGE total enhancement mass (AUC:0.77 vs. 0.54, p < 0.001) and LGE extent (AUC: 0.77 vs. 0.53, p = 0.004). Rad-score combined with Mayo stage had better predictive performance than Mayo stage alone (AUC: 0.86 vs. 0.81, p = 0.03). Rad-score (≥ 0.66) contributed to the risk stratification of all-cause mortality in CA. CONCLUSIONS: Compared to quantitative LGE parameters, radiomics can better predict all-cause mortality in CA, while the combination of radiomics and Mayo stage could provide higher predictive accuracy. CLINICAL RELEVANCE STATEMENT: Radiomics analysis provides incremental value and improved risk stratification for all-cause mortality in patients with cardiac amyloidosis. KEY POINTS: • Radiomics in LV-base was superior to LGE semi-quantitative and quantitative parameters for predicting all-cause mortality in CA. • Rad-score combined with Mayo stage had better predictive performance than Mayo stage alone or radiomics alone. • Rad-score ≥ 0.66 was associated with a significantly increased risk of all-cause mortality in CA patients.

Verum versus Sham brain-computer interface on upper limb function recovery after stroke: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Previous clinical trials have reported that the brain-computer interface (BCI) is a useful management tool for upper limb function recovery (ULFR) in stroke. However, there is insufficient evidence regarding this topic. Thus, this study aimed to investigate the effectiveness of verum versus sham BCI on the ULFR in stroke patients. METHODS: We comprehensively searched the Cochrane Library, PUBMED, EMBASE, Web of Science, and China National Knowledge Infrastructure databases from their inception to January 1, 2023. Randomized clinical trials (RCTs) assessing the effectiveness and safety of BCI for ULFR after stroke were included. The outcomes were the Fugl-Meyer Assessment for Upper Extremity, Wolf Motor Function Test, Modified Barthel Index, motor activity log, and Action Research Arm Test. The methodological quality of all the included randomized controlled trials was evaluated using the Cochrane risk-of-bias tool. Statistical analysis was performed using RevMan 5.4 software. RESULTS: Eleven eligible studies involving 334 patients were included. The results of the meta-analysis showed significant differences in the Fugl-Meyer Assessment for Upper Extremity (mean difference [MD] = 4.78, 95% confidence interval [CI] [1.90, 7.65], I2 = 0%, P = .001) and Modified Barthel Index (MD = 7.37, 95% CI [1.89, 12.84], I2 = 19%, P = .008). However, no significant differences were found on motor activity log (MD = -0.70, 95% CI [-3.17, 1.77]), Action Research Arm Test (MD = 3.05, 95% CI [-8.33, 14.44], I2 = 0%, P = .60), and Wolf Motor Function Test (MD = 4.23, 95% CI [-0.55, 9.01], P = .08). CONCLUSION: BCI may be an effective management strategy for ULFR in stroke patients. Future studies with larger sample size and strict design are still needed to warrant the current findings.

Diagnosis of Cardiac Amyloidosis Using a Radiomics Approach Applied to Late Gadolinium-Enhanced Cardiac Magnetic Resonance Images: A Retrospective, Multicohort, Diagnostic Study.

Objectives: To assess the potential of a radiomics approach of late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) in the diagnosis of cardiac amyloidosis (CA). Materials and Methods: This retrospective study included 200 patients with biopsy-proven light-chain (AL) amyloidosis. CA was diagnosed on the basis of systemic amyloidosis confirmed with evidence of cardiac involvement by imaging and clinical biomarkers. A total of 139 patients [54 ± 8 years, 75 (54%) men] in our institution were divided into training cohort [n = 97, mean age of 53 ± 8 years, 54 (56%) men] and internal validation cohort [n = 42, mean age: 56 ± 8 years, 21 (50%) men] with a ratio of 7:3, while 61 patients [mean age: 60 ± 9 years, 42 (69%) men] from the other two institutions were enrolled for external validation. Radiomics features were extracted from global (all short-axis images from base-to-apex) left ventricular (LV) myocardium and three different segments (basal, midventricular, and apex) on short-axis LGE images using the phase-sensitive reconstruction (PSIR) sequence. The Boruta algorithm was used to select the radiomics features. This model was built using the XGBoost algorithm. The two readers performed qualitative and semiquantitative assessment of the LGE images based on the visual LGE patterns, while the quantitative assessment was measured using a dedicated semi-automatic CMR software. The diagnostic performance of the radiomics and other qualitative and quantitative parameters were compared by a receiver operating characteristic (ROC) curve analysis. A correlation between radiomics and the degree of myocardial involvement by amyloidosis was tested. Results: A total of 1,906 radiomics features were extracted for each LV section. No statistical significance was indicated between any two slices for diagnosing CA, and the highest area under the curve (AUC) was found in basal section {0.92 [95% confidence interval (CI), 0.86-0.97] in the LGE images in the training set, 0.89 (95% CI, 0.79-1.00) in the internal validation set, and 0.92 (95% CI, 0.85-0.99) in the external validation set}, which was superior to the visual assessment and quantitative LGE parameters. Moderate correlations between global or basal radiomics scores (Rad-scores) and Mayo stage in all patients were reported (Spearman's Rho = 0.61, 0.62; all p < 0.01). Conclusion: A radiomics analysis of the LGE images provides incremental information compared with the visual assessment and quantitative parameters on CMR to diagnose CA. Radiomics was moderately correlated with the severity of CA. Further studies are needed to assess the prognostic significance of radiomics in patients with CA.

[18F]PBR146 and [18F]DPA-714 in vivo Imaging of Neuroinflammation in Chronic Hepatic Encephalopathy Rats.

Neuroinflammation is an important pathogenesis of hepatic encephalopathy (HE). The upregulation of translocator protein (TSPO) during neuroinflammation provides an imaging molecular target to evaluate the severity of neuroinflammation in chronic HE rats. [18F]DPA-714 and [18F]PBR146 targeting TSPO are often used for neuroinflammation imaging. This study performed bile duct ligation (BDL) in rats to simulate chronic HE model, tested the behavioral experiments, and conducted [18F]PBR146 and [18F]DPA-714 micro-PET/CT scans followed analyzing the average %ID/g values of the whole brain, brain regions and main organs of subjects. After sacrifice the rats, the blood plasma samples were taken for blood biochemical indexes and plasma inflammatory factor levels examination, the liver and brain specimens were obtained for pathological analysis. The BDL rats showed chronic liver failure with defects in cognition, motor coordination ability and mental state. [18F]PBR146 and [18F]DPA-714 micro-PET/CT imaging results were similar in whole brain of BDL group and Sham group. Besides, some regional brain areas in BDL rats were found abnormal uptakes mainly located in basal ganglia area, auditory cortex, motor cortex, cingulate gyrus, somatosensory cortex, hippocampus, thalamus, midbrain, and medulla oblongata, and these regions also correlated with behavioral alterations. In conclusion, both [18F]PBR146 and [18F]DPA-714 had the similar imaging effects in hepatic encephalopathy models could quantitatively evaluate neuroinflammation load and distribution. The difference brain regions with higher uptake values of radiotracers in BDL rats were correlated with behavioral alterations.

Different posterior hippocampus and default mode network modulation in young APOE ε4 carriers: a functional connectome-informed phenotype longitudinal study.

To determine the functional connectome change pattern based on subregions of the hippocampus in young APOEε4 carriers during a 3-year follow-up. All the participants (n = 213) were tested for resting-state functional MRI, neuropsychological scales, and APOE genotype. The age- and sex-matched APOE ε4/ε3 (23.9 ± 3.2 years old, 6 female/7 male) carriers and APOE ε3/ε3 (22.9 ± 1.6 years old, 7 female/12 male) carriers were finally followed up. The hippocampus and its anterior/middle/posterior subregion-based functional connectivity (FC) patterns were compared between APOEε4 and APOEε3 groups by a two-sample t-test at baseline and mixed-effect analysis at follow-up. The effective connectivity (EC) patterns among the altered regions of interaction effect were examined in the APOEε4 groups. APOEε4 carries displayed saliently enhanced FC in the right anterior/middle hippocampus and core regions of the default mode network (DMN) (P < 0.05 by Gaussian Random Fields (GRF) correction). However, the APOEε4-by-time interaction was evident in the middle/posterior hippocampus with connection to the lateral temporal lobe and anterior cingulate cortex (ACC) (P < 0.05 by GRF correction). Moreover, the APOEε4 group at follow-up showed increased EC separately from both the left middle hippocampus and lateral temporal lobe to the left posterior hippocampus, and its changes of FC/EC significantly correlated with altered memory function. The posterior hippocampus might be especially vulnerable to early modulation in young APOEε4 carriers. Its connection with the lateral temporal lobe, rather than with DMN, might be the early compensative mechanism of memory function regulation influenced by APOE ε4 in the young adults.

Effectiveness of rehabilitation training combined acupuncture for the treatment of neurogenic bladder secondary to spinal cord injury.

BACKGROUND: This study will aim to assess the effectiveness of the rehabilitation training (RT) combined acupuncture for the treatment of patients with neurogenic bladder (NB) secondary to the spinal cord injury (SCI). METHODS: We will conduct a comprehensive literature search from the following databases from the inceptions to the present with no language limitation: PUBMED, EMBASE, Cochrane Library, SinoMed, Web of Science, Allied and Complementary Medicine Database, VIP, WANGFANG, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure. Additionally, we will also search gray literature, including dissertations and conference proceedings. RevMan V.5.3 software will be used for the study selection, assessment of bias of bias, and data synthesis. RESULTS: This study will synthesize the available evidence of RT combined with acupuncture for NB secondary to SCI, including episodes of urinary incontinence, urinary retention, urinary tract infection, bladder overactivity, quality of life, and adverse events. CONCLUSION: This study will determine whether RT combined acupuncture is an effective and safety therapy for NB secondary to SCI. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42019146127.

Neuroinflammation in acute hepatic encephalopathy rats: imaging and therapeutic effectiveness evaluation using 11C-PK11195 and 18F-DPA-714 micro-positron emission tomography.

Neuroinflammation has an important influence in pathogenesis of acute hepatic encephalopathy (AHE). 11C-PK11195 and 18F-DPA-714 targeted to translocator protein (TSPO) have potential application in positron emission tomography (PET) as a molecular probe of neuroinflammation. The aim of this study was to compare these two radiotracers and their effectiveness in detecting neuroinflammation for the imaging of AHE rat models. Furthermore, using the new radiotracer 18F-DPA-714, we analyzed the effectiveness of therapeutic treatment for neuroinflammation in AHE. First, we performed a comparative study of 11C-PK1195 and 18F-DPA-714 PET to image neuroinflammation in AHE rats induced by thioacetamide. Twenty-four rats were divided into either control group (n = 12) or AHE group (n = 12). Next, each group was subdivided depending on the radiotracer used during PET imaging (n = 6). Radiotracer uptake values encompassing the whole brain were compared. Lastly, we used the optimized tracer to monitor anti-neuroinflammation effects in AHE-induced rats. Forty-six rats were divided into four groups: [normal saline (NS) group (n = 13), minocycline (MINO) group (n = 11), dexamethasone (DEXA) group (n = 11), MINO+DEXA group (n = 11)]. 18F-DPA-714 PET was performed and the uptake values were calculated. The rotarod test, biochemical indices, and histopathological examinations were quantitatively measured and compared. AHE rats showed reduced motor ability, elevated ammonia levels, and higher liver function indices (all P < 0.05) with unchanged inflammatory factors (all P > 0.05), compared to control group. Both 11C-PK11195 and 18F-DPA-714 PET can detect neuroinflammation of AHE rats. Behavioral studies showed that MINO and/or DEXA improved the motor ability in AHE rats (P < 0.05); however, no differences were found for liver function or inflammatory markers among the four groups (all P > 0.05). The average uptake values of whole brain and multiple brain areas in the MINO+DEXA group were lower compared to all other groups (all P < 0.05), which was demonstrated by CD11b stains of microglia. Our results show that both 11C-PK11195 and 18F-DPA-714 PET can detect neuroinflammation in AHE-induced rat models. Additionally, the combined use of minocycline and dexamethasone can effectively inhibit neuroinflammation in AHE-induced rats, which can be sensitively monitored by 18F-DPA-714 PET.

Different Hippocampus Functional Connectivity Patterns in Healthy Young Adults with Mutations of APP/Presenilin-1/2 and APOEε4.

This study aims to explore the hippocampus-based functional connectivity patterns in young, healthy APP and/or presenilin-1/2 mutation carriers and APOE ε4 subjects. Seventy-eight healthy young adults (33 male, mean age 24.0 ± 2.2 years; 18 APP and/or presenilin1/2 mutation carriers [APP/presenilin-1/2 group], 30 APOE ε4 subjects [APOE ε4 group], and 30 subjects without the above-mentioned genes [control group]) underwent resting-state functional MR imaging and neuropsychological assessments. Bilateral hippocampus functional connectivity patterns were compared among three groups. The brain regions with statistical differences were then extracted, and correlation analyses were performed between Z values of the brain regions and neuropsychological results. Compared with control group, both APOE ε4 group and APP/presenilin-1/2 group showed increased functional connectivity in medial prefrontal cortex and precuneus for the seeds of bilateral hippocampi. The APOE ε4 group displayed increased functional connectivity from bilateral hippocampi to the left middle temporal gyrus compared with the control group. Moreover, compared with the APP/presenilin-1/2 group, the APOE ε4 group also had markedly increased functional connectivity in right hippocampus-left middle temporal gyrus. The Z values of right hippocampus-left middle temporal gyrus correlated with various neuropsychological results across all the subjects, as well as in APOE ε4 group. Young healthy adults carrying APOE ε4 and APP/presenilin-1/2 displayed different hippocampus functional connectivity patterns, which may underlie the discrepant mechanisms of gene-modulated cognitive dysfunction in Alzheimer's disease.

Altered amygdala and hippocampus effective connectivity in mild cognitive impairment patients with depression: a resting-state functional MR imaging study with granger causality analysis.

Neuroimaging studies have demonstrated that the major depression disorder would increase the risk of dementia in the older with amnestic cognitive impairment. We used granger causality analysis algorithm to explore the amygdala- and hippocampus-based directional connectivity patterns in 12 patients with major depression disorder and amnestic cognitive impairment (mean age: 69.5 ± 10.3 years), 13 amnestic cognitive impairment patients (mean age: 72.7 ± 8.5 years) and 14 healthy controls (mean age: 64.7 ± 7.0 years). Compared with amnestic cognitive impairment patients and control groups respectively, the patients with both major depression disorder and amnestic cognitive impairment displayed increased effective connectivity from the right amygdala to the right lingual and calcarine gyrus, as well as to the bilateral supplementary motor areas. Meanwhile, the patients with both major depression disorder and amnestic cognitive impairment had enhanced effective connectivity from the left superior parietal gyrus, superior and middle occipital gyrus to the left hippocampus, the z values of which was also correlated with the scores of mini-mental state examination and auditory verbal learning test-immediate recall. Our findings indicated that the directional effective connectivity of right amygdala - occipital-parietal lobe - left hippocampus might be the pathway by which major depression disorder inhibited the brain activity in patients with amnestic cognitive impairment.

(18)F-DPA-714 PET Imaging for Detecting Neuroinflammation in Rats with Chronic Hepatic Encephalopathy.

Neuroinflammation is considered to be the pathogenesis of hepatic encephalopathy (HE), and imaging neuroinflammation is implicated in HE management. (11)C-PK11195, a typical translocator protein (TSPO) radiotracer, is used for imaging neuroinflammation. However, it has inherent limitations, such as short half-life and limited availability. The purpose of this study was to demonstrate the efficiency of new generation TSPO radiotracer, (18)F-DPA-714, in detecting and monitoring neuroinflammation of chronic HE. This study was divided into two parts. The first part compared (18)F-DPA-714 and (11)C-PK11195 radiotracers in ten HE induced rats [bile duct ligation (BDL) and fed hyperammonemic diet (HD)] and 6 control rats. The animal subjects underwent dynamic positron emission tomography (PET) during 2-day intervals. The (11)C-PK11195 PET study showed no differences in whole brain average percent injected dose per gram (%ID/g) values at all time points (all P>0.05), while the (18)F-DPA-714 PET study showed higher whole brain average %ID/g values in HE rats compared to control group rats at 900 s to 3300 s after injecting radiotracer (all P<0.05). The second part of the study evaluated the effectiveness of ibuprofen (IBU) treatment to chronic HE. Forty rats were classified into six groups, including Sham+normal saline (NS), Sham+IBU, BDL+NS, BDL+HD+NS, BDL+IBU, and BDL+HD+IBU groups. (18)F-DPA-714 PET was used to image neuroinflammation. Whole and regional brain average %ID/g values, neurological features, inflammatory factors and activated microglia showed better in the IBU groups than in the NS groups (all P<0.05) and no difference was seen in the Sham groups compared to IBU groups (all P>0.05). In conclusion, this study demonstrated that (18)F-DPA-714 is an ideal TPSO radiotracer for imaging neuroinflammation and monitoring anti-neuroinflammation treatment efficacy of chronic HE.

A Multifunctional PB@mSiO2-PEG/DOX Nanoplatform for Combined Photothermal-Chemotherapy of Tumor.

In this work, we design mesoporous silica-coated Prussian blue nanocubes with PEGyltation to construct multifunctional PB@mSiO2-PEG nanocubes. The PB@mSiO2-PEG nanocubes have good biocompatibility, excellent photothermal transformation capacity, in vivo magnetic resonance and photoacoustic imaging ability. After loading antitumor drug doxorubicin (DOX) in the PB@mSiO2-PEG nanocubes, the constructured PB@mSiO2-PEG/DOX nanoplatforms show an excellent pH-responsive drug release character within 48 h, namely, an ultralow cumulative drug release amount of 3.1% at pH 7.4 and a high release amount of 46.6% at pH 5.0. Upon near-infrared laser irradiation, the PB@mSiO2-PEG/DOX nanoplatforms show an enhanced synergistic photothermal and chemical therapeutic efficacy for breast cancer than solo photothermal therapy or chemotherapy.

Chronic thromboembolic pulmonary hypertension: Comparison of dual-energy computed tomography and single photon emission computed tomography in canines.

PURPOSE: To compare diagnostic accuracy between dual-energy CT lung perfused blood volume (Lung PBV) imaging and single photon emission computed tomography (SPECT) in detecting chronic thromboembolic pulmonary hypertension (CTEPH) with histopathological results as reference standard in a canine model. MATERIALS AND METHODS: Eighteen CTEPH canines were included into this experimental study. All procedures including paracentesis, embolization, scanning, pressure measurement and feeding medicine were repeated each two weeks, until systolic/diastolic pressure in canines was ≥ 30/15 mm Hg or mean pulmonary artery pressure ≥ 20 mm Hg, and then sacrificed for histopathology examination. Two radiologists (readers 1 and 2) and two nuclear radiologists (readers 3 and 4) analyzed images of conventional CT pulmonary angiography in dual-energy CT mode, Lung PBV imaging and SPECT, respectively. The presence, numbers, and locations of pulmonary emboli (PE) were recorded on a per-lobe basis. Pathological examination was served as reference standard. Sensitivity, specificity and accuracy of Lung PBV and SPECT were calculated. Kappa statistics were used to quantify inter-reader agreement. RESULTS: With histopathological results as reference standard, the sensitivities of 72.2%, 78.8%, 81.2%, specificities of 75.9%, 87.5%, 84.8%, accuracies of 73.8%, 83.1%, 83.1%, for readers 1, 2 and both with Lung PBV, respectively. Readers 3, 4 and both had sensitivities of 14.3%, 25.7%, 33.3%, specificities of 90.0%, 86.7%, 93.3%, accuracies of 49.2%, 53.8%, 60.0% with SPECT for detecting CTEPH. Inter-reader agreements were good for dual-energy CT (kappa=0.662) and SPECT (k=0.706) for detecting CTEPH. CONCLUSION: Dual-energy CT had a higher accuracy to detect CTEPH than SPECT in this canine model study.

PET and MR imaging of neuroinflammation in hepatic encephalopathy.

Neurological or psychiatric abnormalities associated with hepatic encephalopathy (HE) range from subclinical findings to coma. HE is commonly accompanied with the accumulation of toxic substances in bloodstream. The toxicity effect of hyperammonemia on astrocyte, such as the alteration in neurotransmission, oxidative stress, astrocyte swelling, is considered as an important factor in the pathogenesis of HE. Besides, neuroinflammation has captured more attention in the process of HE, but the mechanism of neuroinflammation leading to HE remains unclear. Molecular imaging techniques such as positron emission tomography (PET) and magnetic resonance imaging (MRI) targeting activated microglia and/ or other mediators appear to be promising noninvasive approaches to assess HE. This review focuses on novel imaging and therapy strategies of neuroinflammation in HE.

Three-dimensional contrast-enhanced magnetic resonance venography for detection of renal vein thrombosis: comparison with multidetector CT venography.

BACKGROUND: Renal vein thrombosis is not uncommon, however, there have been few reports on the diagnostic accuracy of three-dimensional contrast-enhanced magnetic resonance venography (3D-CE-MRV) in the detection of renal vein thrombosis (RVT). PURPOSE: To evaluate the value of 3D-CE-MRV for detecting RVT with multidetector computed tomography (CT) venography as reference standard. MATERIAL AND METHODS: Thirty-two patients with nephrotic syndrome underwent renal CT venography and gradient echo pulse sequence (FLASH 3D) 3D-CE-MRV in a clinical 3-T whole-body MR scanner for suspected RVT with time interval of 0-5 days. RVT was recorded on a per-patient and per-vessel (left renal vein, right renal vein, and inferior vena cava) basis. The diagnostic accuracy of 3D-CE-MRV for detection of RVT was calculated with CT venography as reference standard. Inter-reader agreement for RVT detection was evaluated using Kappa statistics. RESULTS: Of 32 patients, CT venography detected 22 vessels with thrombosis in 17 patients, including five in right renal veins, 14 in left renal veins, and three in inferior vena cava, while 15 patients had no RVT. 3D-CE-MRV detected 21 vessels (21/96, 21.9%) with thrombosis in 16 patients (6/32, 50%), including five in right renal veins, 13 in left renal veins, and three in inferior vena cava, while 16 patients (16/32, 50%) had no RVT. With CT venography as reference standard, the sensitivities and specificities of 3D-CE-MRV for RVT detection were 94.1%, 100%; 95.5%, 100% on a per-patient and a per-vessel basis, respectively. Excellent inter-reader agreement (Kappa value = 0.969, P < 0.001) was observed for RVT detection. CONCLUSION: 3D-CE-MRV has a high diagnostic accuracy in the detection of RVT, which is optimal alternative imaging modality in the detection of RVT.

Acute myocardial infarct detection with dual energy CT: correlation with single photon emission computed tomography myocardial scintigraphy in a canine model.

BACKGROUND: Dual-energy CT (DECT) has been used to detect myocardial infarct. However, few comparable studies with histopathological findings as gold standard have been published. PURPOSE: To investigate the accuracy of DECT iodine maps for detecting acute myocardial infarction compared with single photon emission computed tomography (SPECT) in a canine model using histopathological findings as the reference standard. MATERIAL AND METHODS: A model of myocardial ischemia was created by ligating the left anterior descending (LAD) coronary artery after thoracotomy in six dogs, while another three dogs undergoing thoracotomy without LAD ligature served as a control group. Contrast-enhanced DECT scans of the heart were performed, followed by resting 99mTc-MIBI SPECT myocardial perfusion imaging in all nine dogs before and 3 h after the procedure. Triphenyltetrazolium chloride (TTC) staining was performed and analyzed. In the short axis of the left ventricle, the wall surface was divided into 17 segments, which were assessed for infarcted myocardium on conventional CT from average-weighted data, DECT myocardial iodine maps, conventional CT plus DECT, SPECT, and histopathology. Inter-observer and inter-modality agreement for conventional CT, DECT myocardial iodine maps, and SPECT were calculated. CT value of infracted and non-infracted areas was measured. RESULTS: With the histopathological results as the reference standard, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 75.0% (30/40), 92.0% (104/113), 76.9% (30/39), 91.2% (104/114), 87.6% (134/153) for conventional CT, 85.0% (34/40), 84.1% (95/113), 65.4% (34/52), 94.1% (95/101), 84.3% (129/153) for DECT myocardial iodine maps; 87.5% (35/40), 92.9% (105/113), 81.4% (35/43), 95.5% (105/110), 91.5% (140/153) for conventional CT plus DECT; 82.5% (33/40), 90.3% (102/113), 75.0% (33/44), and 93.6% (102/109), 88.2% (135/153) for SPECT, respectively. Excellent inter-observer agreement (Kappa value >0.8) and good inter-modality agreement (Kappa value >0.6) for each modality were found. CT values of infarcted myocardium (26 ± 22 HU, 36 ± 33 HU, 34 ± 16 HU) were lower than those of non-infarcted myocardium (115 ± 16 HU, 121 ± 28 HU, 123 ± 11 HU) on images of 140 kVp, 80 kVp, and average-weighted 120 kVp images (all P < 0.05). CONCLUSION: With histopathology as the reference standard, DECT myocardial iodine maps can detect acute myocardial infarction with diagnostic accuracy comparable to resting SPECT myocardial perfusion imaging in a canine model. DECT plus conventional CT had a potential to improve the detection of acute myocardial infarction.

Dual-energy CT imaging of thoracic malignancies.

Computed tomography (CT) plays a pivotal role in the detection, characterization, and staging of lung cancer and other thoracic malignancies. Since the introduction of clinically viable dual-energy CT techniques, substantial evidence has accumulated on the use of this modality for imaging chest malignancies. This article describes the principles of dual-energy CT along with suitable image acquisition, reconstruction, and postprocessing strategies for oncologic applications in the chest. The potential of dual-energy CT techniques for the detection, characterization, staging, and surveillance of chest malignancy, as well as the limitations of this modality are discussed.

Thromboembolic complications in nephrotic syndrome: imaging spectrum.

Thromboembolism is a well-known complication of nephrotic syndrome. Pulmonary embolism, renal vein thrombosis, and deep vein thrombosis are the most common venous thromboembolic diseases in patients with nephrotic syndrome, while arterial thromboembolic complications are observed less frequently. Imaging plays an important role in the detection and follow-up of thromboembolism in these patients. The purpose of this essay is to describe the epidemiology, pathophysiological mechanisms, the imaging diagnosis, and treatment of thromboembolism in patients with nephrotic syndrome.

Pulmonary enhancement imaging with dual energy CT for the detection of pulmonary embolism in a rabbit model: comparison to perfusion planar scintigraphy, SPECT and SPECT-CT modalities.

RATIONALE AND OBJECTIVES: Pulmonary enhancement imaging (PEI) derived from dual-energy computed tomographic (CT) imaging has been used to detect perfusion defects from pulmonary embolism (PE). The purpose of this study was to compare the ability of PEI, planar, single photon-emission CT (SPECT) perfusion scintigraphy, and SPECT-CT fusion images to detect perfusion defect in a PE rabbit model. MATERIALS AND METHODS: A PE model was made by injecting Gelfoam into the femoral veins of rabbits (n = 16). After 2 hours, 16 experimental rabbits and three control rabbits underwent contrast-enhanced dual-energy CT scans, from which PEI and CT pulmonary angiography were created, and planar, SPECT, and SPECT-CT fusion images were then obtained and evaluated. Pathologic determination of locations and numbers of lung lobes with PE were recorded. The sensitivity and specificity of the above-mentioned modalities were calculated using the histopathologic results as reference standards. RESULTS: Emboli were present in 31 pulmonary lobes and absent in 64 lung lobes in histopathologic analysis. With the histopathologic findings as the gold standard, sensitivities and specificities of PEI, planar, SPECT, and SPECT-CT fusion images to detect PE were 100% and 96.9%, 71.0% and 84.4%, 77.4% and 90.6%, and 74.2% and 93.8%, respectively. McNemar's tests showed that PEI had higher diagnostic accuracy for the detection of PE than three scintigraphic images (all P values < .05), while three scintigraphic images had similar diagnostic accuracy (all P values = NS). CONCLUSIONS: This study demonstrates that PEI from dual-energy CT imaging can provide higher diagnostic accuracy for detecting PE than planar, SPECT, and SPECT-CT fusion images in a rabbit model.

Detection of pulmonary embolism by dual energy CT: correlation with perfusion scintigraphy and histopathological findings in rabbits.

The purpose of the study was to compare the ability of dual energy CT (DECT) and perfusion scintigraphy (PS) to detect pulmonary embolism (PE) in a rabbit model. Gelfoam (n = 20) or saline (n = 4) was injected into the femoral vein of rabbits. After 2 h, DECT pulmonary angiography (CTPA) was used to create blood flow imaging (BFI) and fusion images. The rabbits then underwent PS. Pathological determination of locations and numbers of lung lobes with PE was recorded. The sensitivity and specificity for BFI, CTPA, fused images and PS were calculated using the pathological results as reference standards. Compared with pathological evaluation, CTPA correctly identified PE in 40 lobes and absence of emboli in 80 lobes, corresponding to a sensitivity and specificity of 100%. BFI and fused images correctly identified PE in 40 lobes and the absence of emboli in 78 lobes, corresponding to a sensitivity and specificity of 100% and 98%, respectively. PS correctly detected 27 lobes with PE and 65 lobes without PE, corresponding to a sensitivity and specificity of 68% and 81%, respectively. BFI, CTPA and fused images derived from a single contrast-enhanced DECT provide a higher diagnostic accuracy of detecting PE than PS in a rabbit model.

Detection of pulmonary embolism using dual-energy computed tomography and correlation with cardiovascular measurements: a preliminary study.

BACKGROUND: Detection of a suspected pulmonary embolism (PE) has been the focus of considerable research over the past few decades. Recently developed dual-source computed tomography (DSCT) scanners with dual-energy mode have been used to detect PE, but the studies on this topic are few. PURPOSE: To assess the clinical value of dual-source, dual-energy CT (DECT) for the diagnosis of suspected PE and to correlate with cardiovascular measurements. MATERIAL AND METHODS: 31 patients with suspected PE underwent contrast-enhanced DSCT scanning with dual-energy mode. Dedicated software for lung perfusion blood volume (PBV) was used in postprocessing. The numbers and locations of PE in PBV images and CT pulmonary angiography (CTPA) were recorded. Sensitivity and specificity were measured, comparing to CTPA as a standard of reference. The relationship between range of iodine mapping abnormality in PBV images and cardiovascular measurements was analyzed. RESULTS: 33 DECT scans were performed in 31 patients. Seventeen patients had PE, while 14 patients had negative results. Filling defects were detected in pulmonary arteries in 44 pulmonary lobar and 99 segmental arteries. Compared to CTPA as a standard of reference, sensitivity and specificity of PBV images were 93.8% and 93.3% on a per-patient basis, 93.2% and 94.7% on a per-lobe basis, and 76.1% and 97.6% on a per-segment basis, respectively. Spearman correlation test showed good positive correlation between the right ventricle (RV)/left ventricle (LV) diameter ratio and pulmonary lobes with emboli for PBV images (R=0.663; P=0.004). CONCLUSION: DECT can provide morphological and functional information of the whole lung in a single contrast-enhanced acquisition; the perfusion defects visualized in PBV images appear to have a positive relationship with the patients' right heart dysfunction.