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Sadako Motoyama,
Masayoshi Sarai,
Kaori Inoue,
Hideki Kawai,
Hajime Ito,
Hiroto Harigaya,
Kayoko Takada,
Yoshihiro Sanda, Hirofumi Anno,
Hiroyuki Naruse,
Junnichi Ishii,
Yukio Ozaki
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ABSTRACT: Background: The role of combined evaluation of myocardial perfusion imaging (MPI; by single-photon emission computed tomography) and computed tomography angiography (CTA) for risk stratification of coronary artery disease was evaluated. For CTA, the extent of luminal stenosis, and also the features of high-risk plaques (HRP, including positive remodeling and low attenuation) were evaluated. Methods and Results: A total of 304 patients (65±11 years, male 72%, median follow-up: 24 months) who underwent CTA and MPI were enrolled in the study. Summed stress scores and summed difference scores (SDS) for MPI, stenosis, and HRP were evaluated, and event rates were compared. Cardiac events were defined as acute coronary event including cardiac death or non-fatal acute myocardial infarction, and unstable angina requiring revascularization. Of 304 patients, 51 (16.8%) underwent early revascularization. In the remaining 253 patients, an event occurred in 11 (4.3%). HRP (hazard ratio [HR], 4.75, P=0.00171) and stenosis (+) with SDS >0 (HR, 4.58, P=0.0461) were significant independent predictors of cardiac event. The event rate for stenosis (+) with SDS >0 was significantly higher than others (log-rank P=0.0490). The event rates were significantly different between HRP(+) and HRP(-) (16.1% vs. 2.7%, log-rank P=0.0013). Conclusions: HRP on CTA was an independent predictor of acute coronary events, as was stenosis (+) with SDS >0, and HRP had increased prognostic value over stenosis and abnormal MPI findings.
Circulation Journal 10/2012; · 3.77 Impact Factor
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Hideki Kawai,
Masayoshi Sarai,
Sadako Motoyama,
Hiroto Harigaya,
Hajime Ito,
Yoshihiro Sanda,
Shankar Biswas, Hirofumi Anno,
Junichi Ishii,
Toyoaki Murohara,
Yukio Ozaki
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ABSTRACT: The differences in the coronary plaque characteristics between patients with mild chronic kidney disease (CKD) (estimated glomerular filtration rate [eGFR] 30-59 ml·min(-1) · 1.73 m(-2)) and those without CKD (eGFR ≥60) by 320-row area detector computed tomography (CT) have not been studied.
We enrolled 487 patients undergoing coronary CT angiography with suspected stable coronary artery disease (mean age: 66.6±10.8 years, 131 with mild CKD) and analyzed 6,352 segments. All coronary plaques were characterized for the presence of vessel remodeling, plaque consistency and the disposition of coronary calcification, and a plaque with positive vessel remodeling and/or low-attenuation was defined as high risk. The number of diseased segments per patient was higher in mild CKD patients than in those without CKD (4.61±3.83 vs. 2.95±3.11, P<0.0001). The prevalence of severe stenosis (≥70% luminal diameter) was significantly higher in cases of mild CKD than in no CKD (35.1% vs. 19.4%, P=0.0003), but there was no significant difference in the prevalence of high-risk plaque (13.0% vs. 9.8%, P=0.3189).
The severity of coronary artery stenosis was higher in the patients with mild CKD, though there was no significant difference in the prevalence of high-risk plaque. We suggest that the high risk of coronary events in patients with CKD is related to the severity of stenosis rather than to the characteristics of plaque.
Circulation Journal 03/2012; 76(6):1436-41. · 3.77 Impact Factor
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ABSTRACT: The purpose of this study was to design and construct a phantom for using motion artifact in the electrocardiogram (ECG)-gated reconstruction image. In addition, the temporal resolution under various conditions was estimated. A stepping motor was used to move the phantom over an arc in a reciprocating manner. The program for controlling the stepping motor permitted the stationary period and the heart rate to be adjusted as desired. Images of the phantom were obtained using a 320-row area-detector computed tomography (ADCT) system under various conditions using the ECG-gated reconstruction method. For estimation, the reconstruction phase was continuously changed and the motion artifacts were quantitatively assessed. The temporal resolution was calculated from the number of motion-free images. Changes in the temporal resolution according to heart rate, rotation time, the number of reconstruction segments and acquisition position in z-axis were also investigated. The measured temporal resolution of ECG-gated half reconstruction is 180 ms, which is in good agreement with the nominal temporal resolution of 175 ms. The measured temporal resolution of ECG-gated segmental reconstruction is in good agreement with the nominal temporal resolution in most cases. The estimated temporal resolution improved to approach the nominal temporal resolution as the number of reconstruction segments was increased. Temporal resolution in changing acquisition position is equal. This study shows that we could design a new phantom for estimating temporal resolution.
Nippon Hoshasen Gijutsu Gakkai zasshi 01/2012; 68(3):209-15.
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Yukio Ozaki,
Masanori Okumura,
Tevfik F Ismail,
Sadako Motoyama,
Hiroyuki Naruse,
Kousuke Hattori,
Hideki Kawai,
Masayoshi Sarai,
Yasushi Takagi,
Junichi Ishii, Hirofumi Anno,
Renu Virmani,
Patrick W Serruys,
Jagat Narula
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ABSTRACT: Pathological and clinical optical coherence tomography (OCT) studies have indicated that acute coronary syndrome (ACS) lesions have either ruptured fibrous caps (RFC-ACS) or intact fibrous caps (IFC-ACS). Although computed tomographic (CT) angiographic characteristics of RFC-ACS include low-attenuation plaques and positive plaque remodelling, features associated with IFC-ACS have not been previously described. The aim of this study was to assess the CT characteristics of IFC-ACS lesions.
Seventy-four patients with ACS/stable angina consented to multimodality imaging, of which 66 underwent CT angiography. Of these, 57 culprit lesions in 57 patients were evaluated with sufficient image quality from all four of OCT, angioscopy, intravascular ultrasound, and CT angiography. Intraluminal thrombus was assessed by OCT/angioscopy, and culprit lesions further classified by OCT-based demonstration of fibrous cap integrity. Of 35 culprit lesions with ACS, OCT revealed IFC with thrombus in 10 (29%) and RFC in the remaining 25 (71%); all 22 lesions with stable angina had intact fibrous caps. Fibrous caps were significantly thinner in RFC-ACS than IFC-ACS and stable angina (45 ± 12, 131 ± 57, and 321 ± 146 μm, respectively; P = 0.001). CT angiography revealed that low-attenuation plaques were more frequently observed in RFC-ACS than IFC-ACS and stable angina (88, 40, and 18%; P = 0.001) lesions. Similarly, positive remodelling was more predominantly seen in RFC-ACS than IFC-ACS and stable angina (96, 20, and 14%; P = 0.001). However, none of the specific CT angiography features clearly distinguished IFC-ACS from stable lesions.
In contrast to the situation with RFC-ACS, distinct culprit lesion characteristics associated with non-rupture-related mechanisms are not identified by CT angiography. It will therefore not be possible to differentiate plaques likely to develop IFC-ACS from stable plaques.
European Heart Journal 06/2011; 32(22):2814-23. · 10.48 Impact Factor
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ABSTRACT: The aim of this study was to evaluate 320-row area detector CT (ADCT) for patients with atrial fibrillation (Af) based on simulated exposure using electrocardiogram RR intervals and comparison with the findings of coronary CT angiography (CCTA) using 64-row multi slice CT (MSCT). The probability of including RR intervals of 900 ms or more was calculated when the acquisition time was varied from 1 to 4 beats. Overall, 51 patients with Af who underwent CCTA were examined. The exposure time for CCTA, the total dose length product (DLP) for the examination, and the image quality (scored 0 to 3: poor to excellent) were compared between ADCT and MSCT. The probability of including RR intervals of 900 ms or more was highly significantly increased at 3 beats of acquisition time. The exposure time using ADCT was reduced by 75% compared with MSCT (ADCT/MSCT: 2.8/11.3 s), and the total DLP was reduced by 40% (ADCT/MSCT: 1398/2277 mGy·cm). Moreover, ADCT provided diagnosable images in all cases, and the mean image quality score for ADCT was significantly higher than that for MSCT (ADCT/MSCT: 2.8/2.4). Thus, 320-row ADCT at 3 beats of acquisition time can provide CCTA images of acceptable quality for patients with Af.
Nippon Hoshasen Gijutsu Gakkai zasshi 01/2011; 67(4):321-7.
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Kaori Inoue,
Sadako Motoyama,
Masayoshi Sarai,
Takahisa Sato,
Hiroto Harigaya,
Tomonori Hara,
Yoshihiro Sanda, Hirofumi Anno,
Takeshi Kondo,
Nathan D Wong,
Jagat Narula,
Yukio Ozaki
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ABSTRACT: This study sought to assess, by serial computed tomography angiography (CTA), the effect of statin treatment on coronary plaque morphology.
In addition to the assessment of luminal stenosis, CTA also allows characterization of plaque morphology. Large, positively remodeled plaques with large necrotic cores have been reported as indicators of plaque instability.
CTA was performed in 32 patients (26 men, ages 64.3 +/- 8.5 years). Of these, 24 received fluvastatin after the baseline study; 8 subjects who refused statin treatment were followed as the control subjects. Serial imaging was performed after a median interval of 12 months. All vessels were examined in every subject, and a 10-mm-long segment was identified for comparison before and after intervention. Total plaque volume, low attenuation plaque (LAP) volume, lumen volume, and remodeling index were calculated.
In the statin-treated patients, the total plaque volume (92.3 +/- 37.7 vs. 76.4 +/- 26.5 mm(3), p < 0.01) and LAP volume (4.9 +/- 7.8 vs. 1.3 +/- 2.3 mm(3), p = 0.01) were significantly reduced over time; however, there was no change in the lumen volume (63.9 +/- 25.3 vs. 65.2 +/- 26.2 mm(3), p = 0.59). On the other hand, no change was observed in the CTA characteristics in the control subjects, including total plaque volume (94.4 +/- 21.2 vs. 98.4 +/- 28.6 mm(3), p = 0.48), LAP volume (2.1 +/- 3.0 vs. 2.3 +/- 3.6 mm(3), p = 0.91), and lumen volume (80.5 +/- 20.7 vs. 75.0 +/- 16.3 mm(3), p = 0.26). The plaque volume change (-15.9 +/- 22.2 vs. 4.0 +/- 14.0 mm(3), p = 0.01) and LAP volume change (-3.7 +/- 7.0 vs. 0.2 +/- 1.5 mm(3), p < 0.01) were significantly greater in the statin than the control group. The lumen volume (1.3 +/- 15.6 vs. -5.5 +/- 13.1 mm(3), p = 0.24) and remodeling index (-2.4 +/- 6.8% vs. -0.3 +/- 6.5%, p = 0.53) did not show the significant differences between the 2 groups. The decrease in the plaque volume was due to reduction in the LAP volume (R = 0.83, p < 0.01), and was not related to any changes in the lumen volume (R = 0.21, p = 0.24).
This preliminary study suggests that serial CTA evaluation of coronary plaques allows for the assessment of interval change in the plaque morphology. Statin treatment results in decreases in the plaque and necrotic core volume. The features known to be associated with plaque instability.
JACC. Cardiovascular imaging 07/2010; 3(7):691-8. · 14.29 Impact Factor
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ABSTRACT: Sixty-four-slice multidetector computed tomography (64-MDCT) has been shown to be a feasible modality for diagnosing coronary artery disease. We studied the accuracy of 64-MDCT in the detection of diseased grafts and also evaluated its limitations.
This study comprised 19 patients who underwent coronary artery bypass grafting and both invasive coronary angiography (ICA) and 64-MDCT. The 64-MDCT images were analyzed for bypass graft occlusion and significant stenosis (>50%) of the anastomosis, and the results were compared with those of ICA.
A total of 90 anastomoses, including 25 proximal anastomoses, were evaluated. Of 65 distal anastomoses, including 5 previously occluded grafts in redo cases, 12 distal anastomoses were identified by 64-MDCT as occluded. In comparison, only 10 grafts were identified as occluded by ICA. The sensitivity, specificity, positive predictive value, and negative predictive value for patency were 100% (10 of 10), 96.5% (55 of 57), 83.3% (10 of 12), and 100% (55 of 55), respectively. The ICA patent grafts were evaluated with respect to stenosis. Invasive coronary angiography identified significant stenosis at only 1 site, whereas 64-MDCT showed significant stenosis at 6 sites. The sensitivity, specificity, positive predictive value, and negative predictive value for stenoses were 100% (1 of 1), 93.1% (67 of 72), 16.7% (1 of 6), and 100% (67 of 67), respectively.
Although 64-MDCT demonstrated diagnostic accuracy in evaluating bypass grafts, limitations of this method include false positive results in cases of competitive flow between the graft and the native coronary artery.
The Annals of thoracic surgery 06/2010; 89(6):1906-11. · 3.74 Impact Factor
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Sadako Motoyama,
Masayoshi Sarai,
Hiroto Harigaya, Hirofumi Anno,
Kaori Inoue,
Tomonori Hara,
Hiroyuki Naruse,
Junichi Ishii,
Hitoshi Hishida,
Nathan D Wong,
Renu Virmani,
Takeshi Kondo,
Yukio Ozaki,
Jagat Narula
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ABSTRACT: In a computed tomographic (CT) angiography study, we identified the characteristics of atherosclerotic lesions that were associated with subsequent development of acute coronary syndrome (ACS).
The CT characteristics of culprit lesions in ACS include positive vessel remodeling (PR) and low-attenuation plaques (LAP). These 2 features have been observed in the lesions that have already resulted in ACS, but their prospective relation to ACS has not been previously described.
In 1,059 patients who underwent CT angiography, atherosclerotic lesions were analyzed for the presence of 2 features: PR and LAP. The remodeling index, and plaque and LAP areas and volumes were calculated. The plaque characteristics of lesions resulting in ACS during the follow-up of 27 +/- 10 months were evaluated.
Of the 45 patients showing plaques with both PR and LAP (2-feature positive plaques), ACS developed in 10 (22.2%), compared with 1 (3.7%) of the 27 patients with plaques displaying either feature (1-feature positive plaques). In only 4 (0.5%) of the 820 patients with neither PR nor LAP (2-feature negative plaques) did ACS develop. None of the 167 patients with normal angiograms had acute coronary events (p < 0.001). ACS was independently predicted by PR and/or LAP (hazard ratio: 22.8, 95% confidence interval: 6.9 to 75.2, p < 0.001). Among 2- or 1-feature positive segments, those resulting in ACS demonstrated significantly larger remodeling index (126.7 +/- 3.9% vs. 113.4 +/- 1.6%, p = 0.003), plaque volume (134.9 +/- 14.1 mm(3) vs. 57.8 +/- 5.7 mm(3), p < 0.001), LAP volume (20.4 +/- 3.4 mm(3) vs. 1.1 +/- 1.4 mm(3), p < 0.001), and percent LAP/total plaque area (21.4 +/- 3.7 mm(2) vs. 7.7 +/- 1.5 mm(2), p = 0.001) compared with segments not resulting in ACS.
The patients demonstrating positively remodeled coronary segments with low-attenuation plaques on CT angiography were at a higher risk of ACS developing over time when compared with patients having lesions without these characteristics.
Journal of the American College of Cardiology 06/2009; 54(1):49-57. · 14.16 Impact Factor
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ABSTRACT: To preliminarily evaluate the feasibility and potential diagnostic utility of whole-brain perfusion computed tomography (CT) performed with a prototype 256-detector row CT system over an extended range covering the entire brain to assess ischemic cerebrovascular disease.
Institutional review board approval and informed consent were obtained. Eleven cases in 10 subjects (six men, four women; mean age, 64.3 years) with intra- or extracranial stenosis were retrospectively evaluated with whole-brain perfusion CT. Three readers independently evaluated perfusion CT data. The diagnostic performance of perfusion CT was visually evaluated with a three-point scale used to assess three factors. Differences between four axial perfusion CT images obtained at the basal ganglia level (hereafter, four-section images) and whole-brain perfusion CT images were assessed with the paired t test. In four subjects, the interval between perfusion CT and single photon emission computed tomography (SPECT) was 1-17 days (mean, 10.3 days). Correlation between perfusion CT findings and SPECT findings was assessed with the Spearman correlation coefficient.
Three-dimensional perfusion CT images and axial, coronal, and sagittal whole-brain perfusion CT images were displayed, and the extent of ischemia was assessed. Mean visual evaluation scores were significantly higher for whole-brain images than for four-section images (4.27 +/- 0.76 [standard deviation] vs 2.55 +/- 0.87). The cerebral blood flow ratios of the ischemic lesions relative to normal regions scanned with perfusion CT (x) and SPECT (y) showed a significant positive correlation (R(2) = 0.76, y = 0.44 x + 0.37, P < .001).
Perfusion CT performed with a 256-detector row CT system can be used to assess the entire brain with administration of one contrast medium bolus. Thus, ischemic regions can be identified with one examination, which has the potential to improve diagnostic utility.
Radiology 01/2009; 250(1):202-11. · 5.73 Impact Factor
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ABSTRACT: The latest multislice computed tomography (MSCT) scanners permit the chest and abdomen to be scanned continuously. However, conventionally, it has been necessary to perform scanning twice using different pitch factors for the cardiac and abdominal regions. We have developed a new scanning technique known as variable pitch factor scanning, in which the table speed is changed during scanning to obtain continuous images from the heart to the abdomen in a single scan, and have evaluated its physical characteristics.
A bead phantom, a comb phantom, and a gold wire placed at an angle were scanned using a 64-row MSCT scanner. The variation in the spatial resolution and continuity of images in the body axis direction because of changes in the pitch factor were evaluated.
Because reconstruction taking the cone angle into consideration was employed, the spatial resolution in the body axis direction was unchanged and the continuity of images in the body axis direction was maintained at a certain level even when the pitch factor was changed.
Variable pitch factor scanning is a useful technique for obtaining continuous images from the heart to the abdomen in a single scan.
Academic Radiology 08/2008; 15(8):1069-74. · 1.69 Impact Factor
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ABSTRACT: The optimal cardiac phases for coronary CT angiography (CTA) are end-systole and mid-diastole, in which cardiac movement is slow. In conventional methods, these cardiac phases are determined by visual selection. We have compared the images in the optimal cardiac phases that were selected by the conventional method and cardiac-phase search software (Phase Navi), and examined the clinical usefulness of Phase Navi in patients with atrial fibrillation. The subjects were 38 patients (regular rhythm: 20, atrial fibrillation: 18). The continuity scores of patients with regular rhythm (Phase Navi, conventional methods) were 2.4+/-0.3-2.5+/-0.3 in end-systole and 2.4+/-0.5-2.4+/-0.4 in mid-diastole. The scores of patients with atrial fibrillation (Phase Navi, conventional methods) were 2.3+/-0.4-2.3+/-0.4 in end-systole, and 2.2+/-0.5-2.1+/-0.6 in mid-diastole. Because the continuity scores of the optimal images from Phase Navi were similar to those from the conventional method, Phase Navi had clinical usefulness in patients with atrial fibrillation.
Nippon Hoshasen Gijutsu Gakkai zasshi 05/2008; 64(4):442-9.
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Journal of the American College of Cardiology 03/2008; 51(7):773-5. · 14.16 Impact Factor
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Sadako Motoyama,
Takeshi Kondo,
Masayoshi Sarai,
Atsushi Sugiura,
Hiroto Harigaya,
Takahisa Sato,
Kaori Inoue,
Masanori Okumura,
Junichi Ishii, Hirofumi Anno,
Renu Virmani,
Yukio Ozaki,
Hitoshi Hishida,
Jagat Narula
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ABSTRACT: To evaluate the feasibility of noninvasive assessment of the characteristics of disrupted atherosclerotic plaques, the authors interrogated the culprit lesions in acute coronary syndromes (ACS) by multislice computed tomography (CT).
Disrupted atherosclerotic plaques responsible for ACS histopathologically demonstrate large lipid cores and positive vascular remodeling. It is expected that plaques vulnerable to rupture should bear similar imaging signatures by CT.
Either 0.5-mm x 16-slice or 64-slice CT was performed in 38 patients with ACS and compared with 33 patients with stable angina pectoris (SAP) before percutaneous coronary intervention. The coronary plaques in ACS and SAP were evaluated for the CT plaque characteristics, including vessel remodeling, consistency of noncalcified plaque (NCP <30 HU or 30 HU <NCP <150 HU), and spotty or large calcification.
In the CT profile of culprit ACS and SAP lesions, the frequency of 30 HU <NCP <150 HU (100% vs. 100%, p = NS) was not different, and large calcification (22% vs. 55%, p = 0.004) was significantly more frequent in the stable lesions. Positive remodeling (87% vs. 12%, p < 0.0001), NCP <30 HU (79% vs. 9%, p < 0.0001), and spotty calcification (63% vs. 21%, p = 0.0005) were significantly more frequent in the ACS lesions. Presence of all 3 (i.e., positive remodeling, NCP <30 HU, and spotty calcification) showed a high positive predictive value, and absence of all 3 showed a high negative predictive value for the culprit plaques associated with ACS.
The CT characteristics of plaques associated with ACS include positive vascular remodeling, low plaque density, and spotty calcification. It is logical to presume that plaques vulnerable to rupture harbor similar characteristics.
Journal of the American College of Cardiology 07/2007; 50(4):319-26. · 14.16 Impact Factor
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Sadako Motoyama,
Takeshi Kondo, Hirofumi Anno,
Atsushi Sugiura,
Yoshihiro Ito,
Kazumasa Mori,
Junichi Ishii,
Takahisa Sato,
Kaori Inoue,
Masayoshi Sarai,
Hitoshi Hishida,
Jagat Narula
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ABSTRACT: It has been proposed that 0.5-mm-slice multislice computed tomography (MSCT) is a noninvasive tool for the detection of atherosclerotic plaque, but the validity of such an assessment has not been demonstrated by an invasive investigation. The present study was performed to compare the 0.5-mm-slice MSCT density of plaques with intravascular ultrasound (IVUS) findings.
Atherosclerotic plaques were characterized in 37 consecutive patients undergoing percutaneous interventions. Based on the IVUS echogenecity, the plaques were classified as soft (n=18), fibrous (n=40) or calcified (n=40). In these 98 plaques, 0.5-mm-slice MSCT plaque density was calculated in 443 regions-of-interest, including 331 lesional foci and 112 luminal cross-sections, and represented as Hounsfield units (HU). MSCT density of the 3 types of plaque was 11+/-12 HU, 78+/-21 HU, and 516 +/-198 HU respectively. Computed tomography density of the (contrast-filled) lumen was 258+/-43 HU. There were statistically highly significant differences in the densitometric characteristics among the 4 groups (soft, fibrous, calcified plaque and lumen) by nonparametric Kruskal-Wallis test (p<0.0001).
The IVUS-based coronary plaque configuration can be accurately identified by 0.5-mm slice MSCT. Noninvasive assessment of plaque characterization will ensure emphasis on the vessel wall beyond the vascular lumen.
Circulation Journal 03/2007; 71(3):363-6. · 3.77 Impact Factor
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Teruhito Kido,
Akira Kurata,
Hiroshi Higashino,
Yoshifumi Sugawara,
Hideki Okayama,
Jitsuo Higaki, Hirofumi Anno,
Kazuhiro Katada,
Shinichiro Mori,
Shuji Tanada,
Masahiro Endo,
Teruhito Mochizuki
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ABSTRACT: Along with the increase of detector rows on the z-axis and a faster gantry rotation speed, the spatial and temporal resolutions of the multislice computed tomography (CT) have been improved for noninvasive coronary artery imaging. We investigated the feasibility of the second specification prototype 256-detector row four-dimensional CT for assessing coronary artery and cardiac function.
The subjects were five patients with coronary artery disease. Contrast medium (40-60 ml) was intravenously administered at the rate of 3-4 ml/s. The patient's whole heart was scanned for 1.5 s to cover at least one cardiac cycle during breathholding without electrocardiographic gating. Parameters used were 0.5 mm slice thickness, 0.5 s/rotation, 120 Kv, and 350 mA, with a half-scan reconstruction algorithm (temporal resolution 250 ms). Twenty-six transaxial datasets were reconstructed at intervals of 50 ms.
The assessability of the coronary arteries in AHA segments 1, 2, 3, 5, 6, 7, 9, and 11 was visually evaluated, resulting in 29 of 32 (90.9%) segments being assessable. Functional assessment was also performed using animated movies without banding artifacts in all cases.
The 256-detector row four-dimensional CT can assess the coronary artery and cardiac function using data during 1.5 s without banding artifacts.
Radiation Medicine 02/2007; 25(1):38-44.
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ABSTRACT: Linitis plastica (scirrhous gastric carcinoma) has a poor prognosis due to delay in diagnosis. Pathological feature of this tumor is diffuse fibrosis of the gastric wall. Detection of small fibrotic lesion in the gastric wall would contribute to early diagnosis of linitis plastica, since the primary lesion usually lacks remarkable protrusion or ulceration.
We performed a multislice CT evaluation of 20 patients with gastric carcinoma with 8 data acquisition system (Aquilion, Toshiba Medical Systems Corporation, Japan).
Out of 20 primary lesions, 3 were diagnosed as relatively small size (less than 10 cm in maximum diameter) linitis plastica. We have successfully demonstrated an en face virtual endoscopic image of the primary ulcers of linitis plastica by arterial-phase, and reactive fibrosis (a desmoplastic response) of the gastric wall by delayed-phase multiplanar reformation (MPR) images perpendicular to the en face image. This preoperative information was useful to evaluate extent of tumor invasion.
The multislice CT evaluation of linitis plastica using delayed-phase images was potentially useful in the detection of relatively small fibrotic lesion and in determining the optimal mode of resection of the stomach.
Abdominal Imaging 01/2007; 32(6):694-7. · 1.73 Impact Factor
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Takahisa Sato, Hirofumi Anno,
Takeshi Kondo,
Hiroto Harigaya,
Kaori Inoue,
Satoshi Kakizawa,
Keita Ohshima,
Masayoshi Sarai,
Hitoshi Hishida,
Kazuhiro Katada,
Masatoshi Kanou
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ABSTRACT: Multislice computed tomography coronary angiography (CTCA) is reconstructed by ECG gating and consequently it is difficult to obtain coronary artery images from patients with arrhythmias, such as atrial fibrillation (AF), by the conventional method.
Eleven patients with AF (9 males, 2 females; mean age: 62.5 years) underwent CTCA using a slice thickness of 0.5 mm, gantry rotation of 0.4 or 0.5 s/rot and pitch of 3.2-4.0. A segmented reconstruction method was used to construct CTCA images at the conventional relative 70-75% (mid-diastolic phase) and 30-35% (end-systolic phase) of the R-R interval and furthermore, the absolute mid-diastolic phase and end-systolic phase from the R wave. Three investigators, who were unaware of the coronary angiography results, independently evaluated the curved multiplanar reconstruction (MPR) images. In both the relative and absolute phase reconstruction, there were motion artifacts in the mid-diastolic than in the end-systolic phase. The absolute phase images had less motion artifacts than the conventional relative phase images. Optimal curved MPR images were obtained in the absolute end-systolic phase. The quality and motion artifacts of those optimal images from AF patients were similar to those from patients in sinus rhythm.
The absolute end-systolic phase is the best time to get optimal CTCA images in AF patients.
Circulation Journal 10/2005; 69(9):1068-73. · 3.77 Impact Factor
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ABSTRACT: One of the newest CT application technologies is cardiac synchronized image reconstruction. In this technology, evaluation of time-resolution is very important. We developed a method of measuring time-resolution in cardiac synchronized reconstruction, and evaluated various scanning protocols. In our experiment, ECG-gated scanning was done by multi-slice CT (Aquilion16 Super Heart Edition, Toshiba Medical Systems Co., Ltd., Japan). The nominal slice thickness was 0.5 mm, and rotation time was 0.5 sec. Input heart rate was set at 40, 45, 50, 55, 60, 70, 75, 80, and 90 bpm, and helical pitch at 3.2, 4.0, and 4.8 (beam-pitch: 0.200, 0.250 and 0.300). We measured FWTM of the obtained sensitivity distribution and compared at each scanning protocol. Time resolution improved as helical pitch decreased and heart rate increased. However, phase-time resolution deteriorated as heart rate increased. The results of our experiment indicated that a segment center was determined by X-ray tube rotation time and heart rate, and the number of segments was determined by heart rate, helical pitch, and reconstruction position. Time resolution changed with X-ray tube rotation time, heart rate, helical pitch, and reconstruction position. In this report, we provide a reference for an optimal scanning protocol in cardiac synchronized image reconstruction.
Nippon Hoshasen Gijutsu Gakkai zasshi 04/2005; 61(3):409-18.
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Wei Cui,
Takeshi Kondo, Hirofumi Anno,
Yu-yin Guo,
Takahisa Sato,
Masayoshi Sarai,
Hitoshi Shinozaki,
Satoshi Kakizawa,
Kouji Sugiura,
Keita Oshima,
Kazuhiro Katada,
Hitoshi Hishida
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ABSTRACT: Multislice helical computed tomography (MSCT) has been used to depict coronary anatomy noninvasively, and proved useful for evaluating ventricular function. The aim of our study was to assess the accuracy of ventricular volume as measured by MSCT.
Fourteen human left ventricular (LV) and 15 right ventricular (RV) casts were scanned by MSCT. A series of LV and RV short-axis images were reconstructed later with slice thickness of 2.0 mm, 3.5 mm, 5.0 mm, 7.0 mm, and 10.0 mm. Ventricular volume was calculated by the multislice tomographic Simpson's method. True LV and RV cast volumes were determined by water displacement.
Both calculated LV and RV volumes correlated highly with the corresponding true volumes (all r >0.95, P <0.01). But with slice thickness from 2.0 mm to 10.0 mm, MSCT scanning overestimated the corresponding true volume by (3.21 +/- 5.95) ml to (12.58 +/- 8.56) ml for LV and (10.22 +/- 8.45) ml to (23.91 +/- 12.24) ml for RV (all P <0.01). There was a very high correlation between the overestimation and the selected slice thickness for both LV and RV volume measurements (r=0.998 and 0.996, P <0.01, respectively). However, when slice thickness was reduced to 5.0 mm, the overestimation for both LV and RV volume measurements became nonsignificant for slice thickness from 2.0 mm to 5.0 mm.
Both LV and RV volumes can be accurately estimated by MSCT. Thinner slice has more accurate calculated volume. However, 5.0 mm slice thickness is thin enough for an accurate measurement of LV or RV volume.
Chinese medical journal 10/2004; 117(9):1283-7. · 0.86 Impact Factor
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Wei Cui, Hirofumi Anno,
Takeshi Kondo,
Yuyin Guo,
Takahisa Sato,
Masayoshi Sarai,
Hitoshi Shinozaki,
Satoshi Kakizawa,
Kouji Sugiura,
Keita Oshima,
Kazuhiro Katada,
Hitoshi Hishida
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ABSTRACT: The complexity of right ventricular (RV) shape makes it more difficult for measuring its volume. However, the short-axis view of the right ventricle usually is crescent and might be assumed as half of a circle. This hypothesis can be applied to calculate RV volume by using the single-plane Simpson's method, but the final RV volume should be about half of the original calculated value. The aim of this study was to test the accuracy of RV volume measurement based on this new assumption in human RV casts.
Fifteen human RV casts were scanned with multislice helical CT and RV sagittal image that corresponds to right anterior oblique view were reconstructed. Single-plane Simpson's method was used to calculate RV volumes. The calculated RV volume was defined as the original calculated value divided by 2. The true RV cast volume was determined by water displacement.
The true RV volume was 64.23+/-24.51 ml; the calculated volume was 53.18+/-26.22 ml. The calculated RV correlated closely with true volume with a regression equation of RV actual volume=21.04 0.406 x RV calculated volume (r=0.869, P<0.001), but significantly underestimated the actual volume by 11.05+/-13.09 ml (P<0.006).
Right ventricular volume could be calculated with single-plane Simpson's method based on the new proposed half-circle model.
International Journal of Cardiology 04/2004; 94(2-3):289-92. · 7.08 Impact Factor
