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1.
Kyohei Nagata Ryoichi Tanaka Hidenobu Takagi Tetuya Fusazaki Yoshihiro Morino Kunihiro Yoshioka 《Japanese journal of radiology》2018,36(1):51-58
Purpose
To assess the utility of transluminal attenuation gradient (TAG) in combination with coronary computed tomography angiography (CTA) for detecting obstructive coronary artery stenosis.Materials and methods
We retrospectively evaluated coronary CTA data in 35 consecutive patients who underwent invasive coronary angiography (ICA). We compared the diagnostic performance of TAG with that of quantitative coronary angiography, which we used as the reference standard. For the combination of TAG and coronary CTA, we designed a logical conjunction model (CCTA&&TAG) as well as a logical disjunction model (CCTA||TAG), and evaluated their diagnostic accuracies.Results
Among 130 vessels of 35 patients, 30 lesions (23%) showed significant stenosis on ICA. TAG predicted significant coronary artery stenosis with a sensitivity of 75%, specificity of 63%, positive predictive value of 40%, negative predictive value of 89%, and accuracy of 66%, and had a cutoff value of ? 15.4 HU/10 mm. The respective values for CCTA&&TAG were 73, 98, 88, 90, and 90%; those for CCTA||TAG were 94, 61, 56, 94, and 72%. CCTA&&TAG improved the diagnostic accuracy significantly more than CCTA||TAG.Conclusion
TAG in conjunction with coronary CTA improves the diagnostic accuracy of coronary CTA.2.
Inge J. van den Hoogen Michiel A. de Graaf Cornelis J. Roos Aukelien C. Leen Aan V. Kharagjitsingh Ron Wolterbeek Lucia J. Kroft J. Wouter Jukema Jeroen J. Bax Arthur J. Scholte 《Journal of nuclear cardiology》2016,23(1):24-36
Aims
Diabetic patients with coronary artery disease (CAD) are often free of chest pain syndrome. A useful modality for non-invasive assessment of CAD is coronary computed tomography angiography (CTA). However, the prognostic value of CAD on coronary CTA in diabetic patients without chest pain syndrome is relatively unknown. Therefore, the aim was to investigate the long-term prognostic value of coronary CTA in a large population diabetic patients without chest pain syndrome.Methods
Between 2005 and 2013, 525 diabetic patients without chest pain syndrome were prospectively included to undergo coronary artery calcium (CAC)-scoring followed by coronary CTA. During follow-up, the composite endpoint of all-cause mortality, non-fatal myocardial infarction (MI), and late revascularization (>90 days) was registered.Results
In total, CAC-scoring was performed in 410 patients and coronary CTA in 444 patients (431 interpretable). After median follow-up of 5.0 (IQR 2.7-6.5) years, the composite endpoint occurred in 65 (14%) patients. Coronary CTA demonstrated a high prevalence of CAD (85%), mostly non-obstructive CAD (51%). Furthermore, patients with a normal CTA had an excellent prognosis (event-rate 3%). An incremental increase in event-rate was observed with increasing CAC-risk category or coronary stenosis severity. Finally, obstructive (50-70%) or severe CAD (>70%) was independently predictive of events (HR 11.10 [2.52;48.79] (P = .001), HR 15.16 [3.01;76.36] (P = .001)). Obstructive (50-70%) or severe CAD (>70%) provided increased value over baseline risk factors.Conclusion
Coronary CTA provided prognostic value in diabetic patients without chest pain syndrome. Most importantly, the prognosis of patients with a normal CTA was excellent.3.
Purpose
To investigate feasibility, image quality and safety of low-tube-voltage, low-contrast-volume comprehensive cardiac and aortoiliac CT angiography (CTA) for planning transcatheter aortic valve replacement (TAVR).Materials and methods
Forty consecutive TAVR candidates prospectively underwent combined CTA of the aortic root and vascular access route (270 mgI/ml iodixanol). Patients were assigned to group A (second-generation dual-source CT [DSCT], 100 kV, 60 ml contrast, 4.0 ml/s flow rate) or group B (third-generation DSCT, 70 kV, 40 ml contrast, 2.5 ml/s flow rate). Vascular attenuation, noise, signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were compared. Subjective image quality was assessed by two observers. Estimated glomerular filtration (eGFR) at CTA and follow-up were measured.Results
Besides a higher body-mass-index in group B (24.8±3.8 kg/m2 vs. 28.1±5.4 kg/m2, P=0.0339), patient characteristics between groups were similar (P≥0.0922). Aortoiliac SNR (P=0.0003) was higher in group B. Cardiac SNR (P=0.0003) and CNR (P=0.0181) were higher in group A. Subjective image quality was similar (P≥0.213) except for aortoiliac image noise (4.42 vs. 4.12, P=0.0374). TAVR-planning measurements were successfully obtained in all patients. There were no significant changes in eGFR among and between groups during follow-up (P≥0.302).Conclusion
TAVR candidates can be safely and effectively evaluated by a comprehensive CTA protocol with low contrast volume using low-tube-voltage acquisition.Key Points
? Third-generation dual-source CT facilitates low-tube-voltage acquisition.? TAVR planning can be performed with reduced contrast volume and radiation dose.? TAVR-planning CT did not result in changes in creatinine levels at follow-up.? TAVR candidates can be safely evaluated by comprehensive low-tube-voltage CT angiography.4.
Bouchra Habib Geryes Raphael Calmon Diala Khraiche Nathalie Boddaert Damien Bonnet Francesca Raimondi 《European radiology》2016,26(7):2030-2038
Objectives
To assess the impact of different protocols on radiation dose and image quality for paediatric coronary computed tomography (cCT).Materials and methods
From January-2012 to June-2014, 140 children who underwent cCT on a 64-slice scanner were included. Two consecutive changes in imaging protocols were performed: 1) the use of adaptive statistical iterative reconstruction (ASIR); 2) the optimization of acquisition parameters. Effective dose (ED) was calculated by conversion of the dose-length product. Image quality was assessed as excellent, good or with significant artefacts.Results
Patients were divided in three age groups: 0–4, 5–7 and 8–18 years. The use of ASIR combined to the adjustment of scan settings allowed a reduction in the median ED of 58 %, 82 % and 85 % in 0–4, 5–7 and 8–18 years group, respectively (7.3?±?1.4 vs 3.1?±?0.7 mSv, 5.5?±?1.6 vs 1?±?1.9 mSv and 5.3?±?5.0 vs 0.8?±?2.0 mSv, all p?<?0,05). Prospective protocol was used in 51 % of children. The reduction in radiation dose was not associated with reduction in diagnostic image quality as assessed by the frequency of coronary segments with excellent or good image quality (88 %).Conclusions
cCT can be obtained at very low radiation doses in children using ASIR, and prospective acquisition with optimized imaging parameters.Key points
? Using ASIR allows 25?% to 41?% reduction in the ED.? Prospective protocol is used up to 51?% of children after premedication.? Low dose is possible using ASIR and optimized prospective paediatric cCT5.
Objectives
To evaluate the efficiency and safety of emergency department (ED) coronary computed tomography angiography (CTA) during a 3-year clinical experience.Methods
Single-center registry of coronary CTA in consecutive ED patients with suspicion of acute coronary syndrome (ACS). The primary outcome was efficiency of coronary CTA defined as the length of hospitalization. Secondary endpoints of safety were defined as the rate of downstream testing, normalcy rates of invasive coronary angiography (ICA), absence of missed ACS, and major adverse cardiac events (MACE) during follow-up, and index radiation exposure.Results
One thousand twenty two consecutive patients were referred for clinical coronary CTA with suspicion of ACS. Overall, median time to discharge home was 10.5 (5.7-24.1) hours. Patient disposition was 42.7 % direct discharge from the ED, 43.2 % discharge from emergency unit, and 14.1 % hospital admission. ACS rate during index hospitalization was 9.1 %. One hundred ninety two patients underwent additional diagnostic imaging and 77 underwent ICA. The positive predictive value of CTA compared to ICA was 78.9 % (95 %-CI 68.1-87.5 %). Median CT radiation exposure was 4.0 (2.5-5.8) mSv. No ACS was missed; MACE at follow-up after negative CTA was 0.2 %.Conclusions
Coronary CTA in an experienced tertiary care setting allows for efficient and safe management of patients with suspicion for ACS.Key points
? ED Coronary CTA using advanced systems is associated with low radiation exposure. ? Negative coronary CTA is associated with low rates of MACE. ? CTA in ED patients enables short median time to discharge home. ? CTA strategy is characterized by few downstream tests including unnecessary ICA.6.
Michiko Suzuki Ryoichi Tanaka Kunihiro Yoshioka Akihiko Abiko Shigeru Ehara 《Japanese journal of radiology》2016,34(3):194-202
Purpose
Accurate evaluation of stenosis in severely calcified arteries is a major challenge in conventional CT angiography (CTA) for peripheral arterial disease (PAD). The aim of this study was to evaluate the efficacy of subtraction CTA compared with conventional CTA and conventional angiography.Materials and methods
175 arterial segments of 31 consecutive patients with PAD who underwent CTA and subsequent digital subtraction angiography (DSA) were evaluated. The percentage stenosis of diseased arteries was measured in iliac arteries with caliper methods on conventional CTA and subtraction CTA, and the concordance of each CTA method with DSA in the identification of >50 % stenosis was evaluated. Interpretation of CTA was always based only on maximum intensity projection (MIP).Results
174 (99 %) segments were interpretable on subtraction CTA and showed a good correlation with DSA (R 2 = 0.844), although 55 (31 %) segments were not evaluable on conventional CTA due to severe calcification. On subtraction CTA, the segmental accuracy, sensitivity, and specificity were 90.5, 78.9, and 80.0 %, respectively.Conclusion
Subtraction CTA is an accurate diagnostic tool for the evaluation of PAD. It may be easier to interpret stenosis in the presence of calcifications using subtraction CTA rather than with the conventional CTA approach. Also, subtraction CTA using only MIP presented a similar accuracy to DSA.7.
Objectives
To validate a method for performing myocardial segmentation based on coronary anatomy using coronary CT angiography (CCTA).Methods
Coronary artery-based myocardial segmentation (CAMS) was developed for use with CCTA. To validate and compare this method with the conventional American Heart Association (AHA) classification, a single coronary occlusion model was prepared and validated using six pigs. The unstained occluded coronary territories of the specimens and corresponding arterial territories from CAMS and AHA segmentations were compared using slice-by-slice matching and 100 virtual myocardial columns.Results
CAMS more precisely predicted ischaemic area than the AHA method, as indicated by 95% versus 76% (p?<?0.001) of the percentage of matched columns (defined as percentage of matched columns of segmentation method divided by number of unstained columns in the specimen). According to the subgroup analyses, CAMS demonstrated a higher percentage of matched columns than the AHA method in the left anterior descending artery (100% vs. 77%; p?<?0.001) and mid- (99% vs. 83%; p?=?0.046) and apical-level territories of the left ventricle (90% vs. 52%; p?=?0.011).Conclusions
CAMS is a feasible method for identifying the corresponding myocardial territories of the coronary arteries using CCTA.Key Points
? CAMS is a feasible method for identifying corresponding coronary territory using CTA ? CAMS is more accurate in predicting coronary territory than the AHA method ? The AHA method may underestimate the ischaemic territory of LAD stenosis8.
Objectives
To evaluate the performance of computed tomography angiography (CTA) ≥64 slices for detecting coronary in-stent restenosis (ISR) and determine the influence of separate characteristics on diagnostic accuracy.Methods
We searched the PubMed, EMBASE and Cochrane databases for studies of CTA ≥64 slices in diagnosing ISR. We pooled data on bivariate modelling, and subgroup analysis was also performed.Results
A total of 35 studies involving 4131 stents were included. The pooled positive likelihood ratio (LR+) and the negative likelihood ratio (LR–) were 14.0 and 0.10, for CTA in diagnosis-significant ISR ≥50%. LR+ and LR– were similar between CTA >64 slices versus 64 slices (both P > 0.99). LR– (0.10) was good for ruling out suspected ISR for <3-mm diameter. Time between CTA and stent implantation >6 months did not affect the ability of CTA for the high LR+ (12.3) and the LR– (0.10). Thick-strut stents ≥100 μm or bifurcation stenting demonstrated inferior accuracy, which was unfavourable for stent imaging.Conclusions
With the high LR+ and LR– of CTA, patients with ISR may be appropriate for non-invasive angiographic follow-up. However, CTA imaging seems unsuitable for patients with characteristics unfavourable for stent imaging, such as thick-strut stents or bifurcation stenting.Key points
? CTA may provide accurate information on characteristics of in-stent restenosis lesions. ? Using CTA, ISR patients may be appropriate for non-invasive angiographic follow-up. ? Stent diameter and the number of slices do not influence CTA. ? CTA seems unsuitable for patients with thick-strut stents or bifurcation stenting.9.
Sampath Santhosh Bhagwant Rai Mittal Deepak Kumar Bhasin Surinder Singh Rana Rajesh Gupta Ashim Das Ritambhra Nada 《Annals of nuclear medicine》2017,31(8):575-581
Objective
To evaluate the additional role of FDG-PET/CT to the conventional multiphasic CECT in the initial staging of pancreatic adenocarcinoma.Methods
54 patients diagnosed with pathologically proven pancreatic malignancy underwent FDG-PET/CECT. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal and metastatic staging were calculated. The statistical difference was calculated by McNemar’s test.Results
Of 54 patients, 15 had distal metastasis. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal staging were 33 vs 89%, 84 vs 100%, 67 vs 100%, 60 vs 90%, and 59 vs 95%, respectively, p < 0.001. The sensitivity, specificity, PPV, NPV, and accuracy of CECT for metastatic staging were 73, 87, 69, 89, and 83%, whereas the accuracy of PET/CT was 100%, p = 0.01. By correctly characterizing unsuspected distant lesions, PET/CT could change management in 19% of patients.Conclusion
FDG-PET/CT can contribute to change in the management in almost one of every five patients of PA evaluated with the standard investigations during the initial staging.10.
Objectives
Multi-detector-row computed tomography angiography (MDCTA) plays an important role in the assessment of patients with suspected coronary artery disease. However, MDCTA tends to overestimate stenosis in calcified coronary artery lesions. The aim of our study was to evaluate the diagnostic performance of calcification-suppressed material density (MD) images produced by using a single-detector single-source dual-energy computed tomography (ssDECT).Methods
We enrolled 67 patients with suspected or known coronary artery disease who underwent ssDECT with rapid kilovolt-switching (80 and 140 kVp). Coronary artery stenosis was evaluated on the basis of MD images and virtual monochromatic (VM) images. The diagnostic performance of the two methods for detecting coronary artery disease was compared with that of invasive coronary angiography as a reference standard.Results
We evaluated 239 calcified segments. In all the segments, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for detecting significant stenosis were respectively 88%, 88%, 75%, 95% and 88% for the MD images, 91%, 71%, 56%, 95% and 77% for the VM images. PPV was significantly higher on the MD images than on the VM images (P?<?0.0001).Conclusions
Calcification-suppressed MD images improved PPV and diagnostic performance for calcified coronary artery lesions.Key Points
? Computed tomography angiography tends to overestimate stenosis in calcified coronary artery. ? Dual-energy CT enables us to suppress calcification of coronary artery lesions. ? Calcification-suppressed material density imaging reduces false-positive diagnosis of calcified lesion.11.
Objectives
The aim of this study is to assess the effect of blood pressure (BP) on coronary computed tomography angiography (CTA) derived computational fractional flow reserve (CTA-FFR).Materials and methods
Twenty-one patients who underwent coronary CTA and invasive FFR were retrospectively identified. Ischemia was defined as invasive FFR ≤0.80. Using a work-in-progress computational fluid dynamics algorithm, CTA-FFR was computed with BP measured before CTA, and simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg respectively. Correlation between CTA-FFR and invasive FFR was assessed using Pearson test. The repeated measuring test was used for multiple comparisons of CTA-FFR values by simulated BP inputs.Results
Twenty-nine vessels (14 with invasive FFR?≤0.80) were assessed. The average CTA-FFR for measured BP (134?±?20/73?±?12 mmHg) was 0.77?±?0.12. Correlation between CTA-FFR by measured BP and invasive FFR was good (r?=?0.735, P?<?0.001). For simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg, the CTA-FFR increased: 0.69?±?0.13, 0.73?±?0.12, 0.75?±?0.12, 0.77?±?0.11, 0.79?±?0.11, and 0.81?±?0.10 respectively (P?<?0.05).Conclusion
Measurement of the BP just before CTA is preferred for accurate CTA-FFR simulation. BP variations in the common range slightly affect CTA-FFR. However, inaccurate BP assumptions differing from the patient-specific BP could cause misinterpretation of borderline significant lesions.Key Points
? The blood pressure (BP) affects the CTA-FFR computation. ? Measured BP before CT examination is preferable for accurate CTA-FFR simulation. ? Inaccurate BP assumptions can cause misinterpretation of borderline significant lesions.12.
Eray Atlı Erhan Akpınar Emre Ünal Berna Oğuz Sayan Mithat Haliloğlu 《Japanese journal of radiology》2018,36(7):437-443
Purpose
To investigate feasibility of high-pitch acquisition protocol for imaging of pediatric abdomen.Materials and methods
The study group consisted of 90 patients scanned with high-pitch acquisition protocol (pitch?=?3) by 64-slice dual-source CT (DSCT) scanner. Fifty-four patients scanned with standard protocol (pitch?=?1.5) by 16-slice single-source CT scanner comprised the control group. Anteroposterior and lateral diameters of abdomen, effective diameter, scan time and length, qualitative and quantitative noise levels, volumetric CT dose index (CTDIvol), dose length product (DLP), and size-specific dose estimations were compared between groups.Results
The mean scan time of high-pitch CT protocol was shorter than control protocol (1.66?±?0.31 vs. 4.1?±?0.75 s; p?<?0.001). The high-pitch protocol reduced the radiation dose by 48% (CTDIvol and DLP values 0.94 mGy and 32.2 mGy-cm vs. 1.59 mGy and 61.5 mGy-cm; p?<?0.001, respectively). Although image noise was higher with high-pitch acquisition, there was no significant effect on diagnostic confidence. Voluntary and involuntary artifacts were less frequent in high-pitch protocol (p?<?0.001). Interobserver agreement was moderate in terms of artifact and very good in terms of diagnostic confidence assessment.Conclusion
High-pitch acquisition protocol by DSCT yields significant radiation dose reduction without compromising image quality and diagnostic confidence for pediatric abdomen imaging.13.
Objectives
Diagnostic accuracy of conventional coronary CT angiography (CCTAconv) may be compromised by blooming artifacts from calcifications or stents. Blooming artifacts may be reduced by subtraction coronary CT angiography (CCTAsub) in which non-contrast and contrast CT data sets are subtracted digitally. We tested whether CCTAsub in patients with severe coronary calcification or stents reduces the number of false-positive stenosis evaluations compared with CCTAconv.Methods
In this study, 180 symptomatic patients scheduled for invasive coronary angiography (ICA) were prospectively enrolled and CT scanned (2013-2016) at three international centers. CCTAconv, and CCTAsub data sets were reconstructed. Target segments were defined as motion-free coronary segments with a suspected stenosis (> 50% of lumen) potentially due to blooming of either calcium or stents. Target segments were evaluated with respect to misregistration artifacts from the CCTAsub reconstruction process, in which case evaluation was omitted. CCTAsub and CCTAconv were compared with ICA. Primary outcome measure was the frequency of false positives by CCTAconv versus CCTAsub to identify > 50% coronary stenosis by ICA on a per-segment level.Results
After exclusion of 76 patients, 104 (14% females) with mean age 67 years and median Agatston score 852 were included. There were 136 target segments with misregistration and 121 target segments without. Accuracy calculations in target segments without misregistration showed a reduction of the false positives from 72% [95% confidence interval (CI): 63-80%] in CCTAconv to 33% (CI:25-42%) in CCTAsub, at the expense of 7% (CI:3-14%) false negatives in CCTAsub.Conclusions
In severely calcified coronary arteries or stents, CCTAsub reduces the false-positive rate in well-aligned, calcified or stent segments suspected of significant stenosis on CCTAconv. Nevertheless, misregistration artifacts are frequent in CCTAsub.Key Points
? A high calcium-score reduces the diagnostic accuracy in patients scanned with cardiac CT. ? These patients would normally need an invasive angiogram for diagnosis. ? In this prospective, multicenter study, subtraction CT, when evaluable, reduces false-positive stenosis evaluations. ? Subtraction coronary CT angiography may, when evaluable, reduce excessive downstream testing.14.
Aimin Ding Guoqing Qiu Wensheng Lin Ling Hu Guangliang Lu Xiang Long Xin Hong Yaohua Chen Xiaoping Luo Qinqin Tang Dongqin Deng 《Japanese journal of radiology》2016,34(12):795-808
Purpose
Fractional flow reserve based on coronary computed tomographic angiography (CCTA; FFRCT) can evaluate functional severity in coronary artery disease (CAD). This study investigated the diagnostic value of FFRCT for determining CAD severity.Materials and methods
Medline, Cochrane, EMBASE, and Google Scholar databases were searched until June 16, 2016 using the following search terms: fractional flow reserve, coronary computed tomography angiography, myocardial ischemia. Randomized controlled trials, two-arm prospective studies, and retrospective studies were included in the analysis.Results
Twenty-one studies were included with a total of 2216 subjects and 2798 vessels. FFRCT, sensitivity per-vessel and per-patient were ≥82% and specificity was ≥73% for diagnosis of ischemia. FFRCT had better diagnostic accuracy and discrimination than CCTA.Conclusion
This study indicates that FFRCT may be a good tool for screening and diagnosing of myocardial ischemia in patients with CAD.15.
Objectives
We evaluated the effect of a single-energy metal artefact reduction (SEMAR) algorithm for metallic coil artefact reduction in body imaging.Methods
Computed tomography angiography (CTA) was performed in 30 patients with metallic coils (10 men, 20 women; mean age, 67.9?±?11 years). Non-SEMAR images were reconstructed with iterative reconstruction alone, and SEMAR images were reconstructed with the iterative reconstruction plus SEMAR algorithms. We compared image noise around metallic coils and the maximum diameters of artefacts from coils between the non-SEMAR and SEMAR images. Two radiologists visually evaluated the metallic coil artefacts utilizing a four-point scale: 1 = extensive; 2 = strong; 3 = mild; 4 = minimal artefacts.Results
The image noise and maximum diameters of the artefacts of the SEMAR images were significantly lower than those of the non-SEMAR images (65.1?±?33.0 HU vs. 29.7?±?10.3 HU; 163.9?±?54.8 mm vs. 10.3?±?19.0 mm, respectively; P?<?0.001). Better visual scores were obtained with the SEMAR technique (3.4?±?0.6 vs. 1.0?±?0.0, P?<?0.001).Conclusions
The SEMAR algorithm significantly reduced artefacts caused by metallic coils compared with the non-SEMAR algorithm. This technique can potentially increase CT performance for the evaluation of post-coil embolization complications.Key Points
? The new algorithm involves a raw data- and image-based reconstruction technique. ? The new algorithm mitigates artefacts from metallic coils on body CT images. ? The new algorithm significantly reduced artefacts caused by metallic coils. ? The metal artefact reduction algorithm improves CT image quality after coil embolization.16.
Introduction
Near-occlusion of the internal carotid artery (ICA) is a significant luminal diameter (LD) reduction beyond a tight atherosclerotic carotid stenosis (CS). Recognition of even subtle near-occlusions is essential to prevent underestimation of the stenosis degree. Our goal was to investigate the prevalence of near-occlusion among CS patients using a single standard criterion to facilitate its recognition, even when distal ICA LD reduction is not visually evident in computed tomography angiography (CTA).Methods
We analysed carotid artery CTAs of 467 patients with moderate-to-severe CS scheduled for endarterectomy. We performed measurements of the bilateral distal ICA LDs from thin axial source images and utilized a 1.0 mm intra-individual side-to-side distal ICA LD difference to distinguish near-occlusions, based on a previous study, aware of the vagaries of measurement. For analysis stratification, we excluded cases with significant carotid pathology affecting LD measurements.Results
We discovered 126 near-occlusions fulfilling our criterion of ipsilateral near-occlusion: the mean LD side-to-side difference (mm) with 95% confidence interval being 1.8 (1.6, 1.9) and a standard deviation of 0.8 mm. Among the 233 cases not meeting our near-occlusion criterion, we found 140 moderate (50–69%) and 93 severe (70–99%) ipsilateral stenoses.Conclusion
The utilization of 1.0 mm cut-off value for the intra-individual distal ICA LD side-to-side difference to distinguish atherosclerotic ICA near-occlusion leads to a relatively high incidence of near-occlusion. In CTA, recently suggested to be used for near-occlusion diagnosis, a discriminatory 1.0 mm cut-off value could function as a pragmatic tool to enhance the detection of even subtle near-occlusions.17.
Purpose
The aim of this study is to assess the value of adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) for reduction of metal artifacts due to dental hardware in carotid CT angiography (CTA).Methods
Thirty-seven patients with dental hardware who underwent carotid CTA were included. CTA was performed with a GE Discovery CT750 HD scanner and reconstructed with filtered back projection (FBP), ASIR, and MBIR. We measured the standard deviation at the cervical segment of the internal carotid artery that was affected most by dental metal artifacts (SD1) and the standard deviation at the common carotid artery that was not affected by the artifact (SD2). We calculated the artifact index (AI) as follows: AI = [(SD1)2 ? (SD2)2]1/2 and compared each AI for FBP, ASIR, and MBIR. Visual assessment of the internal carotid artery was also performed by two neuroradiologists using a five-point scale for each axial and reconstructed sagittal image. The inter-observer agreement was analyzed using weighted kappa analysis.Results
MBIR significantly improved AI compared with FBP and ASIR (p < 0.001, each). We found no significant difference in AI between FBP and ASIR (p = 0.502). The visual score of MBIR was significantly better than those of FBP and ASIR (p < 0.001, each), whereas the scores of ASIR were the same as those of FBP. Kappa values indicated good inter-observer agreements in all reconstructed images (0.747–0.778).Conclusions
MBIR resulted in a significant reduction in artifact from dental hardware in carotid CTA.18.
Purpose
To investigate diagnostic accuracy of 3rd-generation dual-source CT (DSCT) coronary angiography in obese and non-obese patients.Methods
We retrospectively analyzed 76 patients who underwent coronary CT angiography (CCTA) and invasive coronary angiography. Prospectively ECG-triggered acquisition was performed with automated tube voltage selection (ATVS). Patients were dichotomized based on body mass index in groups A (<30 kg/m2, n?=?37) and B (≥30 kg/m2, n?=?39) and based on tube voltage in groups C (<120 kV, n?=?46) and D (120 kV, n?=?30). Coronary arteries were assessed for significant stenoses (≥50 % luminal narrowing) and diagnostic accuracy was calculated.Results
Per-patient overall sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy were 96.9 %, 95.5 %, 93.9 %, 97.7 % and 96.1 %, respectively. Sensitivity and NPV were lower in groups B and D compared to groups A and C, but no statistically significant differences were observed (group A vs. B: sensitivity, 100.0 % vs. 93.3 %, p?=?0.9493; NPV, 100 % vs. 95.5 %, p?=?0.9812; group C vs. D: sensitivity, 100.0 % vs. 92.3 %, p?=?0.8462; NPV, 100.0 % vs. 94.1 %, p?=?0.8285).Conclusion
CCTA using 3rd-generation DSCT and (ATVS) provides high diagnostic accuracy in both non-obese and obese patients.Key Points
? Coronary CTA provides high diagnostic accuracy in non-obese and obese patients. ? Diagnostic accuracy between obese and non-obese patients showed no significant difference.? <120 kV studies were performed in 44 % of obese patients. ? Current radiation dose-saving approaches can be applied independent of body habitus.19.
Objectives
To evaluate the feasibility of myocardial blood flow (MBF) by computed tomography from dynamic CT perfusion (CTP) for detecting myocardial ischemia and infarction assessed by cardiac magnetic resonance (CMR) or single-photon emission computed tomography (SPECT).Methods
Fifty-three patients who underwent stress dynamic CTP and either SPECT (n?=?25) or CMR (n?=?28) were retrospectively selected. Normal and abnormal perfused myocardium (ischemia/infarction) were assessed by SPECT/CMR using 16-segment model. Sensitivity and specificity of CT-MBF (mL/g/min) for detecting the ischemic/infarction and severe infarction were assessed.Results
The abnormal perfused myocardium and severe infarction were seen in SPECT (n?=?90 and n?=?19 of 400 segments) and CMR (n?=?223 and n?=?36 of 448 segments). For detecting the abnormal perfused myocardium, sensitivity and specificity were 80 % (95 %CI, 71-90) and 86 % (95 %CI, 76-91) in SPECT (cut-off MBF, 1.23), and 82 % (95 %CI, 76-88) and 87 % (95 %CI, 80-92) in CMR (cut-off MBF, 1.25). For detecting severe infarction, sensitivity and specificity were 95 % (95 %CI, 52-100) and 72 % (95 %CI, 53-91) in SPECT (cut-off MBF, 0.92), and 78 % (95 %CI, 67-97) and 80 % (95 %CI, 58-86) in CMR (cut-off MBF, 0.98), respectively.Conclusions
Dynamic CTP has a potential to detect abnormal perfused myocardium and severe infarction assessed by SPECT/CMR using comparable cut-off MBF.Key Points
? CT-MBF accurately reflects the severity of myocardial perfusion abnormality. ? CT-MBF provides good diagnostic accuracy for detecting myocardial perfusion abnormalities. ? CT-MBF may assist in stratifying severe myocardial infarction in abnormal perfusion myocardium.20.
Xiaohong?Wu Li?Wang Jingxin?Zhong Jacky?Ko Lin?Shi Yannie?Soo Thomas?Leung Ka?Sing?Wong Jill?Abrigo Xiangyan?Chen