Kunihiro Yoshioka

Computed tomography angiography and perfusion to assess coronary artery stenosis causing perfusion defects by single photon emission computed tomography: the CORE320 study

AIMS To evaluate the diagnostic power of integrating the results of computed tomography angiography (CTA) and CT myocardial perfusion (CTP) to identify coronary artery disease (CAD) defined as a flow limiting coronary artery stenosis causing a perfusion defect by single photon emission computed tomography (SPECT). METHODS AND RESULTS We conducted a multicentre study to evaluate the accuracy of integrated CTA-CTP for the identification of patients with flow-limiting CAD defined by ≥50% stenosis by invasive coronary angiography (ICA) with a corresponding perfusion deficit on stress single photon emission computed tomography (SPECT/MPI). Sixteen centres enroled 381 patients who underwent combined CTA-CTP and SPECT/MPI prior to conventional coronary angiography. All four image modalities were analysed in blinded independent core laboratories. The prevalence of obstructive CAD defined by combined ICA-SPECT/MPI and ICA alone was 38 and 59%, respectively. The patient-based diagnostic accuracy defined by the area under the receiver operating characteristic curve (AUC) of integrated CTA-CTP for detecting or excluding flow-limiting CAD was 0.87 [95% confidence interval (CI): 0.84-0.91]. In patients without prior myocardial infarction, the AUC was 0.90 (95% CI: 0.87-0.94) and in patients without prior CAD the AUC for combined CTA-CTP was 0.93 (95% CI: 0.89-0.97). For the combination of a CTA stenosis ≥50% stenosis and a CTP perfusion deficit, the sensitivity, specificity, positive predictive, and negative predicative values (95% CI) were 80% (72-86), 74% (68-80), 65% (58-72), and 86% (80-90), respectively. For flow-limiting disease defined by ICA-SPECT/MPI, the accuracy of CTA was significantly increased by the addition of CTP at both the patient and vessel levels. CONCLUSIONS The combination of CTA and perfusion correctly identifies patients with flow limiting CAD defined as ≥50 stenosis by ICA causing a perfusion defect by SPECT/MPI.

Coronary CT angiography using 64 detector rows: methods and design of the multi-centre trial CORE-64

Multislice computed tomography (MSCT) for the noninvasive detection of coronary artery stenoses is a promising candidate for widespread clinical application because of its non-invasive nature and high sensitivity and negative predictive value as found in several previous studies using 16 to 64 simultaneous detector rows. A multi-centre study of CT coronary angiography using 16 simultaneous detector rows has shown that 16-slice CT is limited by a high number of nondiagnostic cases and a high false-positive rate. A recent meta-analysis indicated a significant interaction between the size of the study sample and the diagnostic odds ratios suggestive of small study bias, highlighting the importance of evaluating MSCT using 64 simultaneous detector rows in a multi-centre approach with a larger sample size. In this manuscript we detail the objectives and methods of the prospective “CORE-64” trial (“Coronary Evaluation Using Multidetector Spiral Computed Tomography Angiography using 64 Detectors”). This multi-centre trial was unique in that it assessed the diagnostic performance of 64-slice CT coronary angiography in nine centres worldwide in comparison to conventional coronary angiography. In conclusion, the multi-centre, multi-institutional and multi-continental trial CORE-64 has great potential to ultimately assess the per-patient diagnostic performance of coronary CT angiography using 64 simultaneous detector rows.

Patient Characteristics as Predictors of Image Quality and Diagnostic Accuracy of MDCT Compared With Conventional Coronary Angiography for Detecting Coronary Artery Stenoses: CORE-64 Multicenter International Trial

OBJECTIVE The purpose of the study was to investigate patient characteristics associated with image quality and their impact on the diagnostic accuracy of MDCT for the detection of coronary artery stenosis. MATERIALS AND METHODS Two hundred ninety-one patients with a coronary artery calcification (CAC) score of <or=600 Agatston units (214 men and 77 women; mean age, 59.3+/-10.0 years [SD]) were analyzed. An overall image quality score was derived using an ordinal scale. The accuracy of quantitative MDCT to detect significant (>or=50%) stenoses was assessed using quantitative coronary angiography (QCA) per patient and per vessel using a modified 19-segment model. The effect of CAC, obesity, heart rate, and heart rate variability on image quality and accuracy were evaluated by multiple logistic regression. Image quality and accuracy were further analyzed in subgroups of significant predictor variables. Diagnostic analysis was determined for image quality strata using receiver operating characteristic (ROC) curves. RESULTS Increasing body mass index (BMI) (odds ratio [OR]=0.89, p<0.001), increasing heart rate (OR=0.90, p<0.001), and the presence of breathing artifact (OR=4.97, p<or=0.001) were associated with poorer image quality whereas sex, CAC score, and heart rate variability were not. Compared with examinations of white patients, studies of black patients had significantly poorer image quality (OR=0.58, p=0.04). At a vessel level, CAC score (10 Agatston units) (OR=1.03, p=0.012) and patient age (OR=1.02, p=0.04) were significantly associated with the diagnostic accuracy of quantitative MDCT compared with QCA. A trend was observed in differences in the areas under the ROC curves across image quality strata at the vessel level (p=0.08). CONCLUSION Image quality is significantly associated with patient ethnicity, BMI, mean scan heart rate, and the presence of breathing artifact but not with CAC score at a patient level. At a vessel level, CAC score and age were associated with reduced diagnostic accuracy.

Diagnostic Value of Cardiac CT in the Evaluation of Bicuspid Aortic Stenosis: Comparison With Echocardiography and Operative Findings

OBJECTIVE This study was conducted to assess the diagnostic value of cardiac CT for the evaluation of patients with bicuspid aortic valve disease. MATERIALS AND METHODS Fifty consecutive patients with aortic stenosis who underwent surgical valve repair between September 2005 and November 2006 were examined by ECG-gated CT and echocardiography. A 64-MDCT scanner was used. The image findings regarding the number of leaflets (bicuspid or tricuspid) were compared against the intraoperative findings and were statistically analyzed by one-way univariate analysis of variance. The aortic valve area (AVA) was also measured by CT and echocardiography, and the measured values were statistically compared by use of the paired Students t test. RESULTS Seventeen patients had a bicuspid aortic valve, and 33 had a tricuspid aortic valve. In 10 of the 50 patients, echocardiography was unable to depict the type of aortic valve because of extensive calcification. The sensitivity, specificity, positive predictive value, and negative predictive value for the detection of a bicuspid aortic valve were 76.5%, 60.6%, 68.4%, and 95.2%, respectively, for echocardiography and 94.1%, 100%, 100%, and 97.1%, respectively, for CT. The CT findings were not significantly different from the intraoperative findings (p = 0.99), but the echocardiographic findings were (p < 0.05). The AVA measurements obtained by CT and echocardiography were 0.940 ± 0.44 cm(2) and 0.659 ± 0.234 cm(2), respectively, showing a significant difference (p < 0.05). CONCLUSION ECG-gated cardiac CT is useful for the accurate morphologic assessment of bicuspid aortic stenosis, especially in patients with severe valve calcification.

Subtraction Coronary CT Angiography for Calcified Lesions

One of the main problems in coronary angiography using 64-row computed tomography (CT) is that the presence of severe calcification interferes with the assessment of lesions, which reduces diagnostic accuracy and may even make assessment of some coronary artery segments impossible. With 320-row CT, it is possible to avoid this problem by performing subtraction coronary CT, which fully exploits the performance capabilities of the CT system. However, subtraction coronary CT has several limitations. When these limitations have been overcome, this technique is expected to become a useful method for assessing patients with severe calcification and evaluating coronary artery stents.

Behavior of C-reactive protein levels in medically treated aortic dissection and intramural hematoma.

C management of aortic dissection and intramural hematoma not involving the ascending aorta yields acceptable survival outcomes.1–3 However, a variety of aortic events can often arise during the follow-up phase.4–6 Although C-reactive protein (CRP) levels are inevitably elevated in patients with acute aortic dissection and intramural hematoma, variability exists among patients. However, few previous studies have investigated the behavior of CRP levels in these aortic disorders.7 The purpose of this prospective study was to assess the consequences of CRP levels on the course of aortic dissection and intramural hematoma, by means of comparison with findings from serial computed tomography (CT). • • • One hundred eight patients were diagnosed as having acute aortic dissection or intramural hematoma and admitted to our hospital from June 1997 to May 1999. Of these, 47 consecutive cases who presented within 24 hours (median 6 hours) of onset and were treated medically were initially enrolled in this prospective study. Four patients were excluded from this aggregate because of infectious diseases during the study in 3 cases and contraindication to the use of contrast material in 1 case. Data pertaining to the remaining 43 patients were analyzed: involvement of ascending aorta in 11 patients (type A) and no involvement in 32 patients (type B); there were 36 men and 7 women, average age 65.5 years old (range 42 to 84). Indication for medical treatment was based on the following criteria: (1) type B with descending aorta of ,55 mm in diameter, (2) type A with both ascending aorta of ,50 mm in diameter and no blood flow in false lumen of ascending aorta, and (3) patients without compromised organ perfusion, cardiac tamponade, aortic valve involvement, or aortic rupture. Diagnosis and disease classification was made on the basis of 2 imaging modalities: contrast-enhanced electron beam CT with contiguous slices of 6 mm thickness, and gadolinium-enhanced magnetic resonance imaging with a 1.5-T superconducting magnetic unit. Patients with typical aortic intimal flap were diagnosed as classic dissection (n 5 13, including 4 patients with type A). Aortic dissection with thrombosed false lumen (n 5 10, including 2 patients with type A) was defined by a large amount of intramural thrombus with intimal disruption (entry), as distinct from penetrating atherosclerotic ulcer.8 On the day of onset, the findings of hyperdense precontrast crescent in the aortic wall, no intimal flap, no intimal disruption, and no compressed aortic lumen, were considered diagnostic of intramural hematoma (n 5 20, including 5 patients with type A). All participants were initially treated according to a single protocol as follows. During a 4to 7-day stay in an intensive care unit, systolic blood pressure was maintained at ,130 mm Hg. Nicardipine hydrochloride was intravenously infused for the first 48 hours from onset, if appropriate. Thereafter, oral antihypertensive medications were administered in a fixed order. All patients underwent a uniform rehabilitation program that facilitated a stepwise restoration to normal daily life over a 3-week period. Contrast-enhanced electron beam CT was performed on the day of onset, after a few days, and thereafter at 1-week intervals for 4 to 5 weeks during hospitalization. Subsequent follow-up by electron beam CT was carried out at 3-month intervals after discharge (average 16 months). All tests consisted of early and delayed images, and changes in aortic condition were carefully evaluated by a specially trained radiologist and 2 physicians. In intramural hematoma and aortic dissection with thrombosed false lumen, 3 types of serious evolution of hematoma or thrombus were anticipated: (1) perceptible enlargement of localized contrast filling, suggesting secondary formed microdisruption of the intima9 or initial entry site, (2) abrupt expansion of the hematoma or thrombus, and (3) transition to classic dissection. These findings were designated as intramural events. Circulating CRP levels were measured daily until the initial peak had passed, and thereafter once or twice a week until discharge. The measurements were properly added when an abnormal change was found. Re-elevation of CRP levels was defined as an elevation of .1.0 mg/dl after the initial peak level. CRP was measured by latex agglutination nephelometry with an assay sensitivity of 0.3 mg/dl and a normal range of ,0.6 mg/dl. The study protocol was approved by our hospital ethics committee, and informed consent was obtained from all subjects. Intergroup differences in the proportion of patients with CRP re-elevation were compared by chi-square test. The unpaired Student’s t test was used for comparison of CRP levels between the groups. Significance was set at p ,0.05. All values are expressed as mean 6 SD. In 9 of 20 patients with intramural hematoma, From the Departments of Internal Medicine II and Radiology, Iwate Medical University, Morioka, Japan. Dr. Makita’s address is: Department of Internal Medicine II, Iwate Medical University, 19-1 Uchimaru, Morioka 020-8505, Japan. E-mail: makitas@seagreen.ocn.ne.jp. Manuscript received November 22, 1999; revised manuscript received and accepted January 27, 2000.

Analyses of sexual dimorphism of contemporary Japanese using reconstructed three-dimensional CT images – Curvature of the best-fit circle of the greater sciatic notch

We examined various expression methods of sexual dimorphism of the greater sciatic notch (GSN) of the pelvis in contemporary Japanese residents by analyzing the three-dimensional (3D) images reconstructed by multi-slice computed tomography (CT) data, using image-processing and measurement software. Mean error of anthropological measurement values between two skeletonized pelves and their reconstructed 3D-CT images was 1.4%. A spline curve was set along the edge of the GSN of reconstructed pelvic 3D-CT images. Then a best-fit circle for subsets of the spline curve, 5-60mm in length and passing through the deepest point (inflection point) of the GSN, was created, and the radius of the circle (curvature radius) and its ratio to the maximum pelvic height (curvature quotient) were computed. In analysis of images reconstructed from CT data of 180 individuals (male: 91, female: 89), sexes were correctly identified in with 89.4% of specimens, with a spline curve length of 60mm. Because sexing was possible even in deeper regions of the GSN, which are relatively resistant to postmortem damage, the present method may be useful for practical forensic investigation.

Analyses of sexual dimorphism of reconstructed pelvic computed tomography images of contemporary Japanese using curvature of the greater sciatic notch, pubic arch and greater pelvis

Three-dimensional pelvic images were reconstructed from multi-slice CT data of contemporary Japanese (males: 124; females: 104, 25-92 years old), and curvature analysis to examine sexual dimorphism was carried out in the great sciatic notch (GSN), the pubic arch and the greater pelvis in the images. Reconstructed pelvic CT images were visualized fairly well and anatomical landmarks were easily recognizable. When calculating the radii (curvature radii) of the best-fit circles for the spline curve lines set along the edges of the GSNs and of the pubic arches, sexes from these regions were correctly identified in 89.1% (males: 93.8%; females: 83.7%) and 94.7% (males: 97.3%; females: 91.8%) of cases, respectively, by setting an appropriate cut-off value. Furthermore, sexing was possible even in deeper regions of the GSN which are relatively resistant to postmortem damage. Curvature radii of the best-fit spheres of greater pelves showed no significant difference between sexes. However, curvature of the best-fit sphere for the left iliac fossa was significantly larger than that of the right one (p<10(-24)) in males, and the ratios were >1.0 in 88% of all male specimens analyzed. Meanwhile, no significant difference was observed among female samples. Although some left-sided dominancy has been reported in 2-dimensional measurements of the human pelvis, this 3-dimensional laterality in males was much more significant, and is a potential index of sex difference.

The optimal body size index with which to determine iodine dose for hepatic dynamic CT: A prospective multicenter study

PURPOSE To identify the body size parameter that exhibits the best correlation with aortic and hepatic enhancement at hepatic dynamic computed tomography (CT) in a large patient population enrolled in a multicenter study. MATERIALS AND METHODS This prospective study was approved by the ethics committee of each of the 31 participating institutions where 1342 patients were enrolled between April 2012 and September 2013. All patients provided either written or oral informed consent. All patients underwent hepatic dynamic CT, which included preenhanced, hepatic arterial phase (HAP), and portal venous phase (PVP) scanning, performed with the routine scanning protocol of each institution. Changes in CT number (in Hounsfield units) per gram of iodine in the aorta (eA/I) and liver (eL/I) during HAP and PVP scanning were recorded for each patient. Hierarchical multivariate linear regression analysis was performed in which the outcome variable was either eA/I or eL/I; the independent variables were age, sex, one body size parameter (height, body weight, body mass index, lean body weight [LBW], or body surface area), and liver function (aspartate aminotransferase, albumin, and total bilirubin levels). A two-level hierarchical model in which patients were level 1 and the institution was level 2 was used. RESULTS Hierarchical multivariate linear regression analysis revealed that in the population not stratified by sex, body size was significantly correlated with eA/I and eL/I (P < .001) and that LBW exhibited the strongest correlation with eA/I and eL/I (r = -0.561 and r = -0.601, respectively). Sex-stratified analysis showed that LBW was more strongly correlated with eA/I and eL/I in women (r = -0.779 and r = -0.948, respectively) than in men (r = -0.500 and r = -0.494, respectively) or in the nonstratified total population. CONCLUSION Among body size parameters, LBW exhibited the strongest correlation with aortic and hepatic enhancement, especially in women.

Influence of Gelatin-Resorcin-Formalin Glue on Mid-Term Redissection After Aortic Repair

PurposeTo determine whether the development of mid-term redissection after surgery for acute type A aortic dissection using gelatin-resorcin-formalin (GRF) glue could be prevented by applying less formalin.MethodsBetween 1995 and 1999, 59 patients underwent surgery with GRF glue to repair acute type A aortic dissection. Forty-one patients underwent surgery before October 1998, and 18 patients underwent surgery after November 1998. An excessive amount of formalin was used in the former period and less was used in the latter period.ResultsFollow-up computed tomography was done for 34 patients in the former period (Former group) and for 16 patients in the latter period (Latter group). This showed redissection in 19 of the 34 patients in the Former group and in 6 of the 16 patients in the Latter group. There was no significant difference in the frequency of mid-term redissection between the two groups.ConclusionThe development of mid-term redissection of the aortic root was not prevented by applying less formalin in the GRF glue. Thus, we conclude that the cause of redissection is not entirely the result of too much formalin.