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Background: Optimal contrast enhancement is crucial for the detection of coronary artery stenoses and atherosclerotic changes in coronary CT angiography (CTA). Purpose: To demonstrate the feasibility of using the cardiac output (CO) obtained from the test bolus injection data-set (COtest) as a factor in contrast injection rate revision of the following coronary CTA. Material and Methods: The test bolus injection data-sets of 52 consecutive coronary CTAs were examined. COtest was calculated from the test bolus data-set. Aortic peak enhancement (APE) was measured on the following coronary CTA. We simulated the APE at a fixed contrast injection rate of 4 mL/s (simAPE) in each patient. Results: The ranges of COtest and simAPE were 2.82-7.56 L/min and 194-527 Hounsfield Units, respectively. There was a significant negative correlation (R = -0.802, P < 0.001) between simAPE and COtest. Conclusion: COtest can be used for injection rate revision on coronary CTA. [ABSTRACT FROM AUTHOR]

Background: Coronary CT angiography (CCTA) is used daily in acute chest pain triage, although exposing patients to significant radiation dosage. CCTA using prospective ECG gating (PG CCTA) enables significant radiation reduction Purpose: To determine whether the routine use of 128 vs. 64 multidetector CT (MDCT) can increase the proportion of patients scanned using PG CCTA technique, lowering radiation exposure, without decreasing image quality. Material and Methods: The study comprised 232 patients, 116 consecutive patients scanned using 128 MDCT (mean age 49 years, 79 men, BMI 28) and 116 consecutive patients (mean age 50 years, 75 men, BMI 28) which were scanned using 64 MDCT. PG CCTA was performed whenever technically permissible by each type of scanner: 64 MDCT = stable heart rate (HR) <60/min and weight <110 kg; 128 MDCT = stable HR , 70/min and weight <140 kg. All coronary segments were evaluated for image quality using a visual scale of 1-5. An estimated radiation dose was recorded. Results: PC CCTA was performed in 84% and 49% of the 128 and 64 MDCT groups, respectively (P , 0.0001). Average image quality score were 4.6±0.3 and 4.7±0.1 for the 128 and 64 MDCT, respectively (P = 0.08). The mean radiation dose exposure was 6.2±4.8 mSv and 10.4±7.5 mSv for the 128 and 64 MDCT, respectively (P = 0.008). Conclusion: The 128 MDCT scanner enables utilization of PG CCTA technique in a greater proportion of patients, thereby decreasing the related radiation significantly, without hampering image quality. [ABSTRACT FROM AUTHOR]

Backround: Detection of myocardial infarction has been the focus of considerable research over the past few decades. Recently developed dual source computed tomography (DSCT) scanners with dual energy mode have been used to detect myocardial infarction, but the studies on this topic are few. Purpose: To evaluate the feasibility and performance of dual energy CT (DECT) during arterial phase in coronary CT angiography for the detection of chronic infarction compared with late enhancement MRI (LE-MRI) and histopathology in a porcine model of reperfused myocardial infarction. Material and Methods: Myocardial infarctions were induced by 30 min occlusion of the proximal left anterior descending coronary artery in eight minipigs. DECT, post-contrast LE-MRI and histopathology were performed 60 days after infarct induction. The CT scan was performed in dual energy mode using a dedicated protocol. Myocardial iodine distribution was superimposed as color maps on grey scale multiplanar reformats of the heart. Two radiologists in consensus interpreted all imaging studies for presence of gadolinium uptake at LE-MRI reduced iodine content at DECT and hypoenhanced areas in the initial 100 kV coronary CT angiography images that were acquired during the DECT-acquisition. Results were compared with histopathology. Results: Based on evaluable segments, DECT showed a sensitivity and specificity of 0.72 and 0.88; LE-MRI showed a sensitivity and specificity of 0.78 and 0.92; and the 100 kV data-set of the DECT scan showed a sensitivity and specificity of 0.60 and 0.93, respectively, for the detection of histological proved ischemia. Conclusion: DECT during arterial phase coronary CT angiography, which is ordinarily used for coronary artery evaluation, is feasible for the detection of a chronic reperfused myocardial infarction. [ABSTRACT FROM AUTHOR]

Background: Effects of high iodine-concentration contrast material on the image quality of coronary CT angiography (CCTA) have not been well evaluated.Purpose: To compare the image quality and attenuation values of CCTA between patients administered iopromide 370 and iomeprol 400 with the use of 64-slice multidetector CT.Material and Methods: Patients were prospectively enrolled and were randomized into two groups (group A, 151 patients received iopromide 370, iodine flux = 1.48 g I/s; group B, 146 patients received iomeprol 400, iodine flux = 1.60 g I/s). CT attenuation was measured in the coronary arteries and great arteries and measurements were standardized based on an iodine flux of 1.50 g I/s. The image quality of 15 coronary artery segments was graded by two radiologists in consensus with the use of a four-point scale (1 = excellent to 4 = poor enhancement). Non-parametric statistical approaches were used to compare the two groups.Results: The median attenuation values in the coronary arteries were 454 HU and 464 HU for iopromide 370 and iomeprol 400, respectively, and they did not differ (P = 0.26). When standardizing for an iodine flux, significantly higher attenuation values were found for iopromide 370 (median = 460 HU, range = 216–791 HU) compared with iomeprol 400 (median = 435 HU, range = 195–758 HU) (P = 0.006). The median image quality score of coronary arterial segments was 1 (range 1–2) for both groups (P = 0.84).Conclusion: The attenuation values in the coronary arteries after injection of the same amount of two high iodine-concentration contrast materials at the same flow rate with different iodine fluxes are similar with no difference in image quality. With standardization for an iodine flux, the attenuation is significantly higher when using iopromide 370. [ABSTRACT FROM AUTHOR]

Background: Cardiac computed tomography (CT) has become an established complement in cardiac imaging. Thus, optimized image quality is diagnostically crucial. Purpose: To prospectively evaluate whether, by using 64-slice CT, a specific reconstruction interval can be identified providing best image quality for all coronary artery segments and each individual coronary artery. Material and Methods: 311 coronary segments of 14 men and seven women were analyzed using 64-slice CT. Data reconstruction was performed in 5% increments from 5-100% of the R-R interval. Four experienced observers independently evaluated image quality of the coronary arteries according to the AHA classification. A three-point ranking scale was applied: 1, very poor, no evaluation possible; 2, diagnostically sufficient quality; 3, highest image quality, no artifacts. Results: The best reconstruction point for all segments was found to be 65% of the R-R interval (mean value 2.4±0.5; P<0.05). On a per-artery basis, best image quality was again achieved at 65% of the R-R interval: RCA 2.2±0.4, LCA 2.4±0.5, LM 2.5±0.2, LAD 2.3±0.4, LCX 2.3±0.5. Conclusion: By using 64-slice CT, the need for adjusting the reconstruction point to each coronary segment might be overcome. Best image quality was achieved with image reconstruction at 65% of the R-R interval for all coronary segments as well as each coronary artery. [ABSTRACT FROM AUTHOR]

Purpose: To quantify left ventricular function and mass derived from retrospectively ECG-gated 64-detector-row computed tomography coronary angiography data sets in comparison to cine magnetic resonance (MR) imaging as the reference standard. We hypothesized that the administration of beta-blockers prior to multidetector computed tomography (MDCT) coronary angiography has a significant impact on left ventricular functional parameters. Material and Methods: Multiplanar reformations in the short-axis orientation were calculated from axial contrast-enhanced CT images in 21 patients (16 male, five female; age range 41–75 years, mean 64.3±6.8 years) referred for CT coronary angiography. Patients whose heart rates exceeded 60 bpm received 5 mg bisoprolol orally 1 hour before the MDCT examination. In case of insufficient heart-rate reduction, up to four vials (20 mg) of metoprolol were injected intravenously. The end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), cardiac output (CO), and left ventricular mass (LVM) of the reformatted images were analyzed compared to volumetric measurements based on continuous short-axis steady-state free-precession cine MR sequences (TR 3 ms, TE 1.5 ms, FA 60°). Results: On average, each patient received 15.5 mg metoprolol (range 0–20 mg) and 3.85 mg bisoprolol (range 0–5 mg). The mean heart rate was 56±5 bpm during CT and 73±9 bpm during MRI examination. This difference was statistically significant (P<0.05). Mean EDV and ESV measured on MDCT were significantly higher compared to MR (MDCT vs. MR: EDV 164.2±52.5 vs. 144.2±46.7 ml, ESV 77.3±46.6 vs. 63.8±47.3 ml; P<0.05). Mean EF and CO derived from MDCT images were significantly lower compared to MR (MDCT vs. MR: EF 55.4±11.8 vs. 59.3±15.4%, CO 4822±779 vs. 5755±1267 ml; P<0.05). Mean SV and LVM were not significantly different between both methods (MDCT vs. MR: SV 86.8±18.1 vs. 80.3±15.6 ml, P = 0.44; LVM 132.4±42.5 vs. 138.7±39.1 g, P = 0.31). Conclusion: Left ventricular volumes assessed by the newest-generation MDCT scanners are significantly higher compared with MRI, whereas ejection fraction and cardiac output are significantly lower in MDCT. This appears to be a result of the frequent application of beta-blockers prior to MDCT examinations. [ABSTRACT FROM AUTHOR]

Purpose: To investigate prospectively the image quality and diagnostic accuracy of 40-slice computed tomography (CT) for the detection of hemodynamically significant coronary artery disease (CAD) in a non-selected, consecutive patient cohort. Material and Methods: Forty consecutive patients (28 men, 12 women) underwent both 40-slice CT and conventional invasive coronary angiography (ICA) within 10±7 days. The results of both methods were compared on a per-segment and per-patient basis, using ICA as the standard of reference. Results: According to ICA, significant CAD was present in 30/40 patients (75%). Of a total of 545 segments, 43 segments (7.9%) could not be sufficiently evaluated by CT due to motion artifacts in 15 segments (34.9%), small vessel size and suboptimal contrast enhancement in 14 segments (32.6%), severe calcification in 10 segments (23.3%), and opacified adjacent structures such as cardiac veins in four segments (9.3%). Segment-based analysis for detection of significant stenosis >50% yielded an overall sensitivity, specificity, positive predictive value, and negative predictive value of 87%, 99%, 98%, and 95%, respectively. Restricting the assessment to clinically relevant proximal coronary segments led to an increase in sensitivity to 96%, specificity to 99%, and negative predictive value to 99%. Patient-based analysis demonstrated a high negative predictive value (91%) of CT for excluding significant CAD, even when all segments were included in the analysis. Conclusion: In a non-selected patient population with a high prevalence of CAD, 40-slice CT demonstrates high diagnostic accuracy in the assessment of significant CAD per patient and per segment. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the feasibility of volumetric cine imaging in human cardiac studies by comparing in vivo and in vitro coronary angiography using a 256-detector row computed tomography (CT) without ECG gating. Material and Methods: The left and right coronary arteries of two domestic pigs were scanned in vivo and in vitro in cine mode using the 256-detector row CT. The device scanned approximately 100 mm in the cranio-caudal direction with one rotation, with a slice thickness of 0.5 mm. Results: The coronary arteries could be observed to the third-degree branches in vitro, but could be visualized clearly only to the proximal portion (first-degree or second-degree branches) in vivo. Conclusion: Application of cardiac volumetric cine imaging with 256-detector row CT may be a promising means of obtaining diagnostic information and has potential for adoption to human studies. [ABSTRACT FROM AUTHOR]

Purpose: To review the feasibility of infra-inguinal angioplasty in the management of critical limb ischemia (CLI).Material and Methods: Data on 221 patients with 230 critically ischemic limbs, treated with consecutive percutaneous transluminal angioplasty (PTA) at Helsinki University Central Hospital between January 2000 and December 2002 were collected and analyzed retrospectively. Patency, limb salvage, and survival rates were calculated on an intention-to-treat basis. Comparisons were done with univariate (Kaplan-Meier) and multivariate analysis (Cox regression).Results: Overall primary patency, secondary patency, limb salvage, and survival rates were 47%, 59%, 92%, and 76%, respectively, at 12 months. In the multivariate analysis, low toe pressure (< or =30 mmHg) was a significant risk factor for poor patency. Uremia with hemodialysis, low toe pressure (< or =30 mmHg), and hemodynamic failure of the endovascular procedure were found to increase significantly the risk of amputation. Uremia with hemodialysis, coronary artery disease, tissue loss as indication for PTA (Fontaine stage IV), and age over 70 years were all found to increase significantly the risk of death.Conclusion: Infra-inguinal PTA is feasible in patients with CLI and resulted in good limb salvage. [ABSTRACT FROM AUTHOR]

Purpose: To assess the diagnostic value and measurement precision of 3D volume rendering technique (3D-VRT) from retrospectively ECG-gated multislice spiral CT (MSCT) data sets for imaging of the coronary arteries.Material and Methods: In 35 patients, retrospectively ECG-gated MSCT of the heart using a four detector row MSCT scanner with a standardized examination protocol was performed as well as quantitative X-ray coronary angiography (QCA). The MSCT data was assessed on segmental basis using 3D-VRT exclusively. The coronary artery diameters were measured at the origin of each main coronary branch and 1 cm, 3 cm and 5 cm distally. The minimum, maximum and mean diameters were determined from MSCT angiography and compared to QCA.Results: A total of 353 of 525 (67.2%) coronary artery segments were assessable by MSCT angiography. The proximal segments were more often assessable when compared to the distal segments. Stenoses were detected with a sensitivity of 82.6% and a specificity of 92.8%. According to the Bland-Altman method the mean differences between QCA and MSCT ranged from -0.55 to 1.07 mm with limits of agreement from -2.2 mm to -2.7 mm.Conclusion: When compared to QCA, the ability of 3D-VRT to quantitatively assess coronary artery diameters and coronary artery stenoses is insufficient for clinical purposes. [ABSTRACT FROM AUTHOR]

Background: Previously, in our laboratory, synchrotron radiation coronary microangiography (SRCA) using Langendorff-perfused rat hearts could visualize a coronary artery of 50 µm in diameter. However, in vivo rat SRCA poses the problem of compromised temporal resolution due to the rapid heart rate of rats. Purpose: To establish a simple method of in vivo rat SRCA with bradycardia induced by intravenous injection of adenosine triphosphate disodium hydrate (ATP). Material and Methods: SRCA was performed at the Photon Factory of the High Energy Accelerator Research Organization (Tsukuba, Japan). Eight male Wistar rats were anesthetized. A catheter for injecting the contrast material was inserted into the carotid artery. Temporary bradycardia was induced by an intravenous bolus injection of 5 mg of ATP, and SRCA was performed immediately thereafter. Results: After ATP administration, the average heart rate decreased from 388 to 73 beats per minute. As a result, we could detect a coronary artery as small as 45 µm in diameter. Conclusion: Our SRCA system which has a high resolution of 9 µm per pixel could detect a coronary artery as small as 45 µm in diameter in the in vivo rat. [ABSTRACT FROM AUTHOR]

A 58-year-old-man with unstable angina developed a violent retrosternal and interscapular pain during coronary angiography with no associated ECG abnormalities. The patient was immediately submitted to transesophageal echocardiography, which revealed an echo-free space behind the ascending aorta thought to be consistent with an aortic dissection. To confirm this finding the patient underwent contrast-enhanced helical CT, which ruled out a dissection but revealed a small hypoattenuating, ill-defined area within the lateral wall of the left ventricle, consistent with an acute myocardial infarction. The finding was first confirmed by bedside echocardiography and later validated by laboratory tests. Review of the left coronary angiogram showed the culprit lesion at the origin of a major acute marginal branch of the circumflex artery. [ABSTRACT FROM AUTHOR]

Describes advances in coronary magnetic resonance angiography and flow quantification. Development of the segmented FLASH sequence in the late 1980s; Improvements in the efficiency of respiratory gating; Enhancement of gradient performance; Coronary flow techniques.

Purpose: To prospectively register fluoroscopic and cine times in a random fashion, and to measure patient radiation exposure from routine coronary angiography and coronary balloon angioplasty. We also evaluated an optional dose reduction system used during interventions.Material and Methods: The incident radiation to the patient was measured as kerma area product (KAP) in Gycm(2), obtained from an ionisation chamber mounted on the undercouch tube during 65 coronary angiography procedures and another 53 percutaneous transluminal coronary angioplasties (including 29 stent procedures), mostly directly following complete coronary angiography.Results and Conclusion: The values from coronary angiography were comparable to other reports with a mean fluoroscopic time of 4.4 min and a mean KAP value of 62.6 Gycm(2). The corresponding figures from coronary balloon angioplasty without stenting were lower than otherwise reported, with 8.2 min and 47.9 Gycm(2), respectively. The use of coronary stents did prolong the mean fluoroscopic time (10.5 min) but did not significantly enhance the patient mean radiation dose (51.4 Gycm(2)). The dose reduction technique resulted in a significant KAP value reduction of 57%. In conclusion, with regard to radiation exposure, coronary angiography and balloon angioplasty are considered safe procedures. [ABSTRACT FROM AUTHOR]

Analyzes preclinical data and initial experience with magnetic resonance coronary angiography on pigs obtained with an intravascular agent coded B-22956/1, a low molecular weight gadolinium chelate. Drug dosage; Delineation of coronaries; Potential of the drug.

The article comments on the prototype for a new 256-row computed tomography (CT) technology used for the imaging of coronary arteries. Key issues discussed include the key features and specifications of the CT technology, its key applications in medical radiography and several research topics relevant to the device including the image reconstruction algorithm.

Evaluates clinical results of breath-hold targeted volume magnetic resonance coronary angiography used to detect stenoses. Visualization of major coronary segments; Diagnostic sensitivity and specificity; Reliability in routine clinical setting.

Reports on the advances in the magnetic resonance (MR) angiography of coronary arteries. MR imaging sequences; Variations in MR techniques; Development of different magnetic resonance imaging techniques applied in the area.

Compares gadolinium-BOPTA and gadolinium-DTPA-enhanced magnetic resonance angiography (MRA) in the assessment of carotid artery stenosis. Differences between the two MRA techniques; Accuracy in determining the degree of stenosis.