320-row Area Detector CT Research Articles

A Case in Which Identification of Cardiac Scar Tissue by MDCT Was Effective in Ablation for Ventricular Tachycardia – A Secondary Publication

During catheterization of ventricular tachycardia, it is often found difficult to identify the origin of ventricular tachycardia when tachycardia is not induced during the procedure or hemodynamics are disrupted. Late gadolinium enhancement (LGE) in cardiac MRI and late Iodine enhancement (LIE) in cardiac CT are reportedly performed to identify myocardial scar tissue and estimate the origin of ventricular tachycardia preoperatively. However, although LGE is useful for identifying the origin of tachycardia, the slice thickness is large and imaging takes a long time, and if a premature beat occurs or the device is inserted during imaging, a good image cannot be obtained. On the other hand, LIE also has poor resolution, making it difficult to take clear images. In this case report, the origin of ventricular tachycardia was presumed preoperatively using a new image processing method called Subtraction Myocardial Image for Late Iodine Enhancement (SMILIE) using a 320-row Area Detector CT, which was useful during catheter ablation.

Electrocardiography-gated non-helical 320-row area detector CT angiography for transcatheter occlusion of patent ductus arteriosus in a small breed dog.

Electrocardiography-gated non-helical 320-row area detector CT angiography for transcatheter occlusion of patent ductus arteriosus in a small breed dog.

NEIM-07 DIFFERENTIAL DIAGNOSIS OF TUMOR RECURRENCE AND RADIATION NECROSIS AFTER STEREOTACTIC RADIOTHERAPY FOR BRAIN METASTASES WITH 320-ROW ADCT PERFUSION IMAGE AND T1/T2 MATCH: RADIOLOGICAL AND PATHOLOGICAL ANALYSIS

BACKGROUND AND PURPOSERadiation necrosis occurs from 6 months to several years following stereotactic irradiation (STI) for brain metastases when tumor recurrences are also most likely. Conventional MR imaging does not provide sufficient information to differentiate between radiation necrosis and tumor recurrence. Methionine-PET, FDG-PET and MR spectroscopy sometimes lead to false positive findings. We applied 320-row area detector CT perfusion imaging for the differentiation because it shows vascularity of lesions in the whole brain. MR T1/T2 match sign also evaluate because it is convenient diagnostic method. METHODBetween October 2006 and September 2021, 48 lesions enlarged in 46 patients 3 to 122 months (median: 11 months) after STI. Differential diagnosis was performed with CT perfusion imaging and MR T1/T2 match sign. To calculate the regional cerebral blood volume (rCBV), the regions of interest (ROIs) were located in the enhanced areas. The lesions progressively increased in size or became symptomatic were resected and diagnosed by pathological examination. RESULTSMean age was 63 years, and 60% were male. Primary were lung 31, breast 9, kidney 3, colon 2, melanoma 2, and uterus 1. Mean time to progression from STI was 11 months (range; 3-122). Pathological diagnosis revealed 38 lesions (79%) had tumor recurrence, and 10 (21%) had radiation necrosis. A cut off value rCBV of greater than 3.0 analyzed by ROC curve provided the best sensitivity and specificity for identifying recurrent metastatic tumors, at 89% and 100%, respectively. T1/T2 match sign was provided sensitivity and specificity for identifying recurrent tumors, at 84% and 90%, respectively. To estimate intralesional pathological heterogeneity, contradistinction of CBV map and T1/T2 match sign is useful for the choice of intraoperative maneuver. CONCLUSIONPerfusion CT imaging and T1/T2 match sign demonstrated reliable methods for differentiating tumor recurrence from radiation necrosis after STI.

Cut-Out Towne-View Whole-Brain 320-Row Four-Dimensional Computed Tomography Angiography for Assessing the Anterior Intracranial Collateral Status: A Retrospective Study.

Whole-brain four-dimensional computed tomography angiography (W4D-CTA) using a 320-row area detector CT (320r-ADCT) has been applied before thrombectomy. Endovascular physicians require images with high interrater reliability (IRR) for making appropriate decisions. However, the 320r-ADCT gantry cannot be tilted, and the patient’s head position influences the anteroposterior (AP)-view W4D-CTA images. This study aimed to determine which W4D-CTA images are appropriate pre-thrombectomy, whether the unedited AP view or cut-out Towne view. This study included the W4D-CTA images of acute stroke patients with occlusion of the internal carotid artery or the middle cerebral artery (MCA) from April to July 2021. Images produced by 320r-ADCT were transferred to a workstation. Unedited AP-view images were automatically generated. Towne-view images were cut out for this study. Collateral status was evaluated as poor, intermediate, or good based on the visualization of the MCA peripheral branches. In addition, the IRR was assessed using intraclass correlation coefficients (ICC) (2,1). Fifteen patients were analyzed. In the unedited AP-view and cut-out Towne-view W4D-CTA images, the ICC (2,1) were 0.147 and 0.796, respectively. Cut-out Towne-view W4D-CTA images with substantial IRR are superior to the unedited AP-view images for assessing the anterior intracranial collateral status.

Dosimetric Evaluation of CyberKnife Synchrony System for Liver Tumors With Respiratory Phase Shifts.

This study evaluated the effects of the respiratory phase shifts between liver tumor and chest wall motions on the dose distribution for the CyberKnife Synchrony respiratory tracking system (SRTS). Eight patients who received stereotactic body radiotherapy for hepatocellular carcinoma or liver metastases were analyzed. Three-dimensional (3D) motion of the implanted fiducial markers and vertical motion of the sternal bone were derived from the four-dimensional computed tomography (4D-CT) images acquired with a 320-row area detector CT. For each patient, Gaussian random numbers were generated for the standard deviation of the tracking error calculated from the phase shift and a literature. For each voxel of the target, the dose delivered from each beam was calculated 100 times with the random 3D offsets representing the tracking error. The median respiratory phase shifts were 6.0% and 4.6% for the anterior-posterior (AP) and superior-inferior (SI) directions, respectively. The median motion tracking errors influenced by respiratory phase shifts were 1.21 mm and 0.96 mm for the AP and SI directions, respectively. The change in the dose covering 90% of the target (D90%) was within 1.1% when median phase shifts were considered. When evaluating the 90th percentile of the phase shifts, the D90% decreased up to 6.6%. We have developed a technique to estimate the impact of the respiratory phase shifts on the dose distribution of a liver tumor treated with the SRTS. The calculation of the respiratory phase shifts from the area-detector 4D-CT will be valuable to improve the tracking accuracy of the SRTS.

The usefulness of subtraction coronary computed tomography angiography for in-stent restenosis assessment of patients with CoCr stent using 320-row area detector CT.

The aim of this study was to assess in-stent restenosis (ISR) of coronary artery for patients with CoCr stent using subtraction coronary computed tomography angiography (CCTA) with one-breath-hold scan on 320-row area detector CT, invasive coronary angiography (ICA) as clinical standard.Patients who were referred for CCTA from January 2020 to May 2021 were retrospectively analyzed. Pre-contrast and CCTA was performed with dedicated one-breath-hold subtraction scan protocol and post processing to get subtracted-CCTA image without stent. Subjective image qualities and diagnosable rate were analyzed for CCTA and subtracted-CCTA respectively. The ISR degree of each stent was evaluated both on CCTA and subtracted-CCTA images. The receiver-operating characteristic curve with sensitivity, specificity, accuracy of CCTA, and subtracted-CCTA in the diagnosis of ISR were calculated with ICA as reference.Forty patients with 85 CoCr coronary stents of 3 to 3.5 mm diameter with ICA confirmation within 1 month were finally included. Subtracted-CCTA showed more diagnosable segments of stent (91.76% [78/85]) than those of CCTA (50.59% [43/85]) (P < .001). The subjective image quality score of CCTA was 2.23 ± 1.32 while 3.41 ± 0.90 on subtracted-CCTA (P < .001). Both subtracted-CCTA and CCTA showed high consistency with ICA (Kappa = 0.795 and 0.918 respectively). The area under the curve was 0.607 for CCTA and 0.757 for subtracted-CCTA (P < .001) for stent based diagnose, respectively. The sensitivity, specificity, accuracy of CCTA, and subtracted-CCTA were 90.0%, 97.0%, 95.3%, and 87.5%, 100.0%, 97.43%, respectively.Subtracted-CCTA showed improved diagnose performance for ISR, which potentially reduce further follow-up ICA procedures for patients with CoCr stents.

Incremental Diagnostic Value of CT Fractional Flow Reserve Using Subtraction Method in Patients with Severe Calcification: A Pilot Study.

Although on-site workstation-based CT fractional flow reserve (CT-FFR) is an emerging method for assessing vessel-specific ischemia in coronary artery disease, severe calcification is a significant factor affecting CT-FFR’s diagnostic performance. The subtraction method significantly improves the diagnostic value with respect to anatomic stenosis for patients with severe calcification in coronary CT angiography (CCTA). We evaluated the diagnostic capability of CT-FFR using the subtraction method (subtraction CT-FFR) in patients with severe calcification. This study included 32 patients with 45 lesions with severe calcification (Agatston score >400) who underwent both CCTA and subtraction CCTA using 320-row area detector CT and also received invasive FFR within 90 days. The diagnostic capabilities of CT-FFR and subtraction CT-FFR were compared. The sensitivities, specificities, positive predictive values (PPVs), and negative predictive values (NPVs) of CT-FFR vs. subtraction CT-FFR for detecting hemodynamically significant stenosis, defined as FFR ≤ 0.8, were 84.6% vs. 92.3%, 59.4% vs. 75.0%, 45.8% vs. 60.0%, and 90.5% vs. 96.0%, respectively. The area under the curve for subtraction CT-FFR was significantly higher than for CT-FFR (0.84 vs. 0.70) (p = 0.04). The inter-observer and intra-observer variabilities of subtraction CT-FFR were 0.76 and 0.75, respectively. In patients with severe calcification, subtraction CT-FFR had an incremental diagnostic value over CT-FFR, increasing the specificity and PPV while maintaining the sensitivity and NPV with high reproducibility.

Subtraction iodine imaging with area detector CT to improve tumor delineation and measurability of tumor size and depth of invasion in tongue squamous cell carcinoma

PurposeTumor size and depth of invasion (DOI) are mandatory assessments for tumor classification in tongue cancer but are often non-assessable on CT due to dental artifacts. This study investigated whether subtraction iodine imaging (SII) would improve tumor delineation and measurability.Materials and methodsFifty-seven consecutive patients with tongue cancer, who underwent scanning with a 320-row area detector CT with contrast administration and were treated with surgical resection, were retrospectively evaluated. CT was reconstructed with single-energy projection-based metallic artifact reduction (sCT). SII was generated by subtracting the pre-contrast volume scans from the post-contrast volume scans using a high-resolution deformable registration algorithm. MRI scans were also evaluated for comparing the ability of measurements. Two radiologists visually graded the tumor delineation using a 5-point scale. Tumor size and DOI were measured wherever possible. The tumor delineation score was compared using the Wilcoxon signed-rank method. Spearman’s correlations between imaging and pathological measurements were calculated. Intraclass correlation coefficients of measurements between readers were estimated.ResultsThe tumor delineation score was greater on sCT-plus-SII than on sCT alone (medians: 3 and 1, respectively; p < 0.001), with higher number of detectable cases observed with sCT-plus-SII (36/57 [63.2%]) than sCT alone (21/57 [36.8%]). Tumor size and DOI measurability were higher with sCT-plus-SII (29/57 [50.9%]) than with sCT alone (17/57 [29.8%]). MRI had the highest detectability (52/57 [91.2%]) and measurability (46/57 [80.7%]). Correlation coefficients between radiological and pathological tumor size and DOI were similar for sCT (0.83–0.88), sCT-plus-SII (0.78–0.84), and MRI (0.78–0.90). Intraclass correlation coefficients were higher than 0.95 for each modality.ConclusionsSII improves detectability and measurability of tumor size and DOI in patients with oral tongue squamous cell carcinoma, thus increasing the diagnostic potential. SII may also be beneficial for cases unevaluable on MRI due to artifacts or for patients with contraindications to MRI.

Urodynamic 4D-CT evaluation: 320-row area detector CT scanner combined with PhyZiodynamics software analysis provides an innovative system to evaluate urinary flow and outlet obstructions

Background Evaluation of the morphology of the lower urinary tract as well as the movements associated with urination are required for the symptomatic diagnosis of lower urinary tract obstruction as well as the assessment of postoperative adaptation. However, no tool currently exists for direct and easy patient evaluation. Purpose To evaluate lower urinary tract obstruction and postoperative adaptation using a four-dimensional (4D) virtual reality urination image (urodynamic 4D-CT image). Material and Methods We used a 320-row area detector CT scanner and PhyZiodynamics image analysis software to perform 197 urodynamic 4D-CT examinations on 175 first-time patients between January 2014 and March 2017. Results A comparison of the obtained images before and after holmium laser enucleation of the prostate revealed the morphological changes due to prostate enucleation and enabled visualization of the ideal urination conditions, showing that the anatomical structural changes during urination and the opening of the urethra play a major role in improving voiding function. Conclusion Using low-dosage radiation, the sharply defined moving image obtained via urodynamic 4D-CT examination can be utilized as a physiological diagnostic tool to evaluate a series of urinary movements from any angle between the prostate, urethra, and bladder in a unitary manner with the time axis added. There was negligible patient impact. This technique could provide new opportunities for the diagnosis of lower urinary tract symptoms and post-surgical adaptation assessment.

Assessment of longitudinal beam property and contrast uniformity for 256- and 320-row area detector computed tomography scanners in the 160-mm nonhelical volume-acquisition mode.

BackgroundBecause the x‐ray property of patient longitudinal axis in area detector computed tomography (ADCT) depends on a heel effect, radiation dose and beam quality are not uniform along the long axis of the patient.ObjectiveThis study aimed to measure the longitudinal beam properties and contrast uniformity of ADCT scanners in the 160‐mm nonhelical volume‐acquisition (NVA) mode and provide useful datasets for the radiation dose reduction in ADCT examinations.Materials and MethodsTwo different types of ADCT scanners were used in this study. To assess the heel effect in 256‐ and 320‐row ADCT scanners, we measured dose profile, half‐value layer, and iodine contrast uniformity along longitudinal beam direction.ResultsThe maximum effective energy difference within a 160‐mm x‐ray beam is approximately 4 keV. Maximum radiation dose on the anode side of the x‐ray tube showed approximately 40%–45% reduction compared with that on the isocenter position; the heel effect properties longitudinally differed throughout the x‐ray beam, and the decrease in the radiation dose in 256‐ and 320‐row ADCT scanners was observed on the patient table side and gantry side respectively. The CT numbers of iodinated solutions for 256‐row ADCT scanner were independent of the heel effect; nevertheless, the CT numbers of 320‐row ADCT scanner tended to increase on the patient table (cathode) side.ConclusionThis study reveals that the radiation dose on the anode side of the x‐ray tube shows approximately 40%–45% reduction compared with that on the isocenter position, and the heel effect properties for 256‐ and 320‐row ADCT scanners longitudinally differ throughout the x‐ray beam. The x‐ray tube for individual ADCT scanners is mounted in an opposite direction along the long axis of the patient.

Tumour volume comparison between 16-row multi-detector computed tomography and 320-row area-detector computed tomography in patients with small lung tumours treated with stereotactic body radiotherapy: Effect of respiratory motion

PurposeWe compared image quality and volume of a moving simulated tumour and of lung tumours in patients who were treated with stereotactic body radiotherapy (SBRT) in a 16-row multi-detector CT (MDCT) versus a 320-row area-detector CT (ADCT). Tumour volumes in each respiratory phase were also evaluated. Materials and MethodsWe acquired static and four-dimensional CT (4DCT) images of a moving phantom with 10- and 30-mm amplitudes with three periods of patterns (2, 4, and 6 s). Breath-hold and 4DCT images were acquired for 12 lung tumour patients who underwent SBRT. Image data were acquired via MDCT and ADCT. The tumours were delineated in each respiratory phase and their volumes in end-expiratory/end-inspiratory phase and mid-respiratory phase were compared. ResultsIn the phantom study, tumour volumes were smaller and closer to the static image when evaluated by ADCT than by MDCT. In the clinical study, average tumour volumes ± standard deviations were 9.58 ± 1.07 cm3 with MDCT (2.5-mm slice), and 7.12 ± 0.23 cm3 with ADCT (p < 0.01). Tumour volumes were closer to that of the breath hold CT in all patients evaluated by ADCT than by MDCT. Unlike MDCT, tumour volumes acquired by ADCT were smaller in end-expiratory or end-inspiratory phase than in the mid-respiratory phase. ConclusionsTumour volumes in each of the respiratory phases in ADCT were significantly smaller and closer to the static image than the corresponding volumes in MDCT. This suggests that treated volume can be reduced if ADCT is used in treatment planning.

A "one-stop-shop" 4D CTA protocol using 320-row CT for advanced imaging in acute ischemic stroke: a technical note.

This technical note describes a novel CT scan protocol that includes a non-enhanced CT, dynamic CTA, and perfusion of the whole brain and CTA of the carotid arteries using a 320-row area detector CT scanner, with a unique contrast injection and acceptable radiation exposure dose in patients presenting with acute ischemic stroke. The acquisition parameters and reconstruction parameters will be discussed including the use of model-based iterative reconstruction (MBIR), time summing (tMIP), and subtraction techniques to optimize the results of this protocol.Key Points• Scanning on a 320-row area detector CT can achieve both brain perfusion with dynamic angiography and reconstructed arterial and venous CTA, and supra aortic trunk angiography, in a single acquisition. • It provides, in a single exam, a full diagnostic workup, i.e., all the acquisitions that are needed to make a quick decision, with reasonable exposure to ionizing radiation and reduced amount of medium contrast, in case of acute ischemic stroke presentation.

Bone Subtraction Iodine Imaging Using Area Detector CT for Evaluation of Skull Base Invasion by Nasopharyngeal Carcinoma.

Conventional CT has generally lower detectability of bone marrow invasion than MR imaging due to lower tissue contrast. The purpose of this study was to compare the diagnostic performance of conventional CT alone or in combination with bone subtraction iodine imaging using area detector CT for the evaluation of skull base invasion in patients with nasopharyngeal carcinoma. Forty-four consecutive patients who underwent contrast-enhanced CT using 320-row area detector CT and contrast-enhanced MR imaging for nasopharyngeal carcinoma staging between April 2012 and November 2017 were enrolled in this retrospective study. Bone subtraction iodine images were generated by subtracting pre- and postcontrast volume scans using a high-resolution deformable registration algorithm. Two blinded observers evaluated skull base invasion at multiple sites (sphenoid body, clivus, bilateral base of the pterygoid process, and petrous bone) using conventional CT images alone or in combination with bone subtraction iodine images. Examination of MR and CT images by an experienced neuroradiologist was the reference standard for evaluating sensitivity, specificity, and area under the receiver operating characteristic curve. Twenty-six patients (59%) showed skull base invasion at 84 sites on the reference standard. Conventional CT plus bone subtraction iodine images showed higher sensitivity (92.9% versus 78.6%, P = .02) and specificity (95.6% versus 86.1%, P = .01) than conventional CT images alone for evaluating skull base invasion. The area under the receiver operating characteristic curve for conventional CT plus bone subtraction iodine (0.98) was significantly larger (P < .001) than the area under the receiver operating characteristic curve for conventional CT alone (0.90). Conventional CT plus bone subtraction iodine performs more closely to the accuracy of combining CT and MR imaging compared with conventional CT alone.

The usefulness of low radiation dose subtraction coronary computed tomography angiography for patients with calcification using 320-row area detector CT

BackgroundAlthough subtraction coronary computed tomography angiography (S-CCTA) has recently been developed to improve the diagnostic ability in patients with severe calcification, increase in radiation exposure remains a concern. The usefulness of S-CCTA using a low-radiation dose protocol was investigated. MethodsS-CCTA in 320-row area detector CT was performed on 84 consecutive patients with suspected obstructive coronary artery disease with Agatston score ≥100. Reconstruction and radiation dose were changed according to the slow filling time (SF) (137.5ms<SF≤262.5ms. Half reconstruction without reduction of the current, 262.5ms<SF≤275ms: automatic patient motion correction with 50% reduction, SF≥275ms: full reconstruction with 70% reduction) at a tube voltage of 100kV. The percentage of patients with non-diagnostic stenosis of calcified coronary artery lesions was calculated in conventional (C-) CCTA, and S-CCTA was calculated based on 84 patients (446 segments) bases. In 27 patients (137 segments) examined by invasive coronary angiography (ICA), the diagnostic ability was investigated regarding the ICA findings as reference standard. ResultsThe percentage of non-diagnostic patients and segments on C-CCTA vs. S-CCTA was 40.5% vs. 9.5% and 16.4% vs. 2.9%, respectively. The Agatston score was 589.3±655.3, and the total effective radiation dose (non-contrast scan and C-CCTA) was 2.7±1.1mSv. In the 27 patients, 137 segments area under the curve of S-CCTA (0.939, 95% CI: 0.895–0.983) for the ICA findings as reference standard was significantly higher than that of C-CCTA (0.785, 95% CI: 0.713–0.858) (p<0.0001). ConclusionThe diagnostic ability of S-CCTA performed following the low-radiation dose protocol for patients with calcification was superior to that of C-CCTA alone.

Preliminary study of time maximum intensity projection computed tomography imaging for the detection of early ischemic change in patient with acute ischemic stroke.

Noncontrast computed tomography (NCCT) has been used for the detection of early ischemic change (EIC); however, correct interpretation of NCCT findings requires much clinical experience. This study aimed to assess the accuracy of time maximum intensity projection computed tomography technique (tMIP), which reflects the maximum value for the time phase direction from the dynamic volume data for each projected plane, for detection of EIC, against that of NCCT.Retrospective review of NCCT, cerebral blood volume in CT perfusion (CTP-CBV), and tMIP of 186 lesions from 280 regions evaluated by Alberta Stroke Program Early CT Score (ASPECTS) in 14 patients with acute middle cerebral artery stroke who had undergone whole-brain CTP using 320-row area detector CT was performed. Four radiologists reviewed EIC on NCCT, CTP-CBV, and tMIP in each ASPECTS region at onset using the continuous certainty factor method. Receiver operating characteristic analysis was performed to compare the relative performance for detection of EIC. The correlations were evaluated.tMIP-color showed the best discriminative value for detection of EIC. There were significant differences in the area under the curve for NCCT and tMIP-color, CTP-CBV (P < .05). Scatter plots of ASPECTS showed a positive significant correlation between NCCT, tMIP-gray, tMIP-color, and the follow-up study (NCCT, r = 0.32, P = .0166; tMIP-gray, r = 0.44, P = .0007; tMIP-color, r = 0.34, P = .0104).Because tMIP provides a high contrast parenchymal image with anatomical and vascular information in 1 sequential scan, it showed greater accuracy for detection of EIC and predicted the final infarct extent more accurately than NCCT based on ASPECTS.

Evaluation of the Dynamics of the Tongue Using 320-row Area Detector CT for Patients with Tongue Resection

Evaluation of the Dynamics of the Tongue Using 320-row Area Detector CT for Patients with Tongue Resection

Abstract 21405: Dynamic Enhancement Pattern is Different Between Unstable and Stable Coronary Plaque: Analysis With 320-Row Area Detector Computed Tomography

Introduction: Intraplaque neovascularization is a marker of unstable coronary plaque. We investigated a difference in dynamic enhancement pattern of coronary plaque between stable and unstable angina pectoris, using 320-row area detector computed tomography (CT), which enables whole-heart volumetric acquisition in a single gantry rotation. Hypothesis &amp; Methods: We analyzed 106 coronary plaque segments in 38 patients (mean age 69.8±8.3 years, 32 male) with angina pectoris (13 stable, 25 unstable) who underwent coronary CT and percutaneous coronary intervention (PCI). Coronary plaques were evaluated using 320-row area detector CT with and without contrast enhancement. Culprit plaques (PCI target) of unstable patients were defined as unstable plaque(n=35), whereas culprit plaques of stable patients and non-culprit plaque were defined as stable plaque(n=71). Coronary plaque without contrast enhancement, corresponding to the plaque detected by contrast enhanced CT, was identified using unique calcification as a landmark. The mean Hounsfield unit (HU) in the coronary plaque was measured, and the presence of positive vascular remodeling was evaluated. Coronary artery stenosis was quantified by coronary angiography. Results: Unstable patients were younger than stable patients (66.6±7.2 vs 76.1±6.7 years, p&lt;0.01). Positive vascular remodeling and spotty calcification was more frequently observed in unstable than stable patients (68.4% vs 15.4%, p&lt; 0.01 and 45.5% vs 86.4%, p&lt;0.05 respectively). Coronary artery stenosis was not different between the 2 groups. In CT without contrast enhancement, plaque HU was not different between the 2 groups (unstable: 25.0±32.4 vs stable: 24.9±33.1). With contrast enhancement, plaque HU was significantly elevated in both groups from those without contrast enhancement to 53.9±24.1 (unstable: p&lt;0.01) and to 42.6±33.5 (stable: p&lt;0.01). Unstable plaque showed higher enhancement (delta HU) than stable plaque (28.9±23.5 vs 17.7±25.5, p=0.024). Conclusions: Dynamic enhancement pattern is different between unstable and stable coronary plaque. Compared to stable plaque, unstable plaque shows higher contrast enhancement, suggesting the increased neovascularization in the plaque.

The effect of bolus volume on laryngeal closure and UES opening in swallowing: Kinematic analysis using 320-row area detector CT study.

This study investigated the effects of three different volumes of honey-thick liquid on the temporal characteristics of swallowing. Twenty-six healthy subjects (15 males, 11 females) underwent 320-row area detector CT scan while swallowing 3, 10 and 20mL of honey-thick liquid barium. Three-dimensional images were created at 10images/s. Kinematic events involving six structures (velopharynx, hyoid bone, epiglottis, laryngeal vestibule (LV), true vocal cords (TVC), upper esophageal sphincter (UES)) and timing of bolus movement were timed using frame by frame analysis. The overall sequence of events did not differ across three volumes; however, increasing bolus volume significantly changed the onset and termination of events. The bolus head reached to pharynx and esophagus earlier and the duration of bolus passing through UES was significantly longer in 10 and 20mL compared to 3mL (P<.05). Consequently, the onset of UES opening was significantly earlier with increased volume (P<.05). LV and TVC closure occurred later in 20mL compared to 3mL (P<.05). These changes in motion of pharynx and larynx appeared to promote swallow safety by preventing aspiration, suggesting that anatomical structure movements adapt in response to bolus volume. Our findings also suggest that the pharyngeal swallow behaviours may be modified by afferents in the oral cavity. The three-dimensional visualization and quantitative measurements provided by 320-ADCT provide essential benchmarks for understanding swallowing, both normal and abnormal.

Submillisievert imaging protocol using full reconstruction and advanced patient motion correction in 320-row area detector coronary CT angiography.

Radiation exposure remains a concern in the use of coronary CT angiography (CCTA). Full reconstruction (Full) and reconstruction using advanced patient motion correction (APMC) could obtain a lower radiation dose using low tube current scanning in a 320-row Area Detector CT (320-ADCT). The radiation dose for an imaging protocol using Full and APMC in daily practice was estimated. A total of 209 patients who underwent CCTA in 1 rotation scanning with 100 kv and adaptive iterative dose reduction 3D in 320-ADCT were enrolled. Imaging protocols were classified into 3 groups based on estimated slow filling time: (1) slow filling time ≥ 275 msec, Full with 30% of usual tube current (N = 43)(Full30%mA) (2) 206.3 msec ≤ slow filling time < 275msec, APMC with 50% of usual tube current (N = 48)(APMC50%mA); and (3) 137.5msec ≤ slow filling time < 206.3msec, Half reconstruction with usual tube current (N = 118)(Half100%mA). Radiation dose was estimated by the effective dose. The diagnostic accuracy of CCTA was compared with that of invasive coronary angiography in 28 patients. The effective doses of Full30%mA, APMC50%mA, and Half100%mA were 0.77 ± 0.31, 1.30 ± 0.85, and 1.98 ± 0.68, respectively. Of 28 patients, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value in vessel-based analyses were: Full30%mA, 66.7, 82.4, 80.0, 40.0, and 93.3%; APMC50%mA, 100.0, 80.0, 83.3, 50.05, and 100.0%; and Half100%mA, 90.9, 83.0, 86.3, 78.95, and 92.9%, respectively. An imaging protocol using Full30%mA and APMC50%mA was one of the methods how radiation dose could be reduced radiation dose maintained diagnostic accuracy compared to imaging using conventional Half100%mA.

Inferring the effects of saliva on liquid bolus flow using computer simulation

Computer simulation of liquid bolus flow is used to test the assumption that a slip boundary condition approximates a healthy swallow due to the presence of saliva lubricating the bolus. Six dynamic, 320-row area detector CT (ADCT) sequences of normal subjects swallowing thin, nectar, and honey-thick liquids are used in this work. The aerodigestive tract is segmented from the images in order to create a dynamic 3D geometry, which is subsequently used to drive a Smoothed Particle Hydrodynamics (SPH) fluid simulation of the bolus. The results show that the no-slip simulation, approximating no-lubrication, provides a closer match to the ADCT bolus images than the slip simulation, particularly in the oral phase. This finding suggests that the role of saliva in swallowing liquid boluses is not to lubricate the aerodigestive tract, and that there is another reason for its importance in normal swallowing of liquids.