Single Injection Of Contrast Material Research Articles

Reduced radiation dose and volume of contrast medium in heart rate-based, one-stop computed tomography angiography of coronary, carotid and cerebrovascular arteries.

Computed tomography angiography (CTA) is a reliable, non-invasive screening method for diagnosing panvascular disease. By using low contrast agent volume, CTA imaging enables one-stop multi-organ scanning, thereby minimizing the potential risk of contrast-induced nephropathy in patients with impaired renal function. To evaluate the feasibility of one-stop CTA following a heart rate (HR)-based protocol using a low volume of contrast medium (CM) for examination of the coronary, carotid and cerebrovascular arteries. Sixty patients undergoing coronary carotid, and cerebrovascular CTA after a single injection of CM were recruited and randomly divided into two groups. Group A (n = 30) underwent CTA following a traditional protocol. The timing of the scans in Group B (n = 30) was determined according to the patient's HR. The CT values for the thoracic aorta (432.2 ± 104.28 HU), anterior cerebral artery (303.96 ± 99.29 HU), and right coronary artery (366.70 ± 85.10 HU) in Group A did not differ significantly from those in Group B (445.80 ± 106.13, 293.73 ± 75.25 and 344.13 ± 111.04 HU, respectively). The qualities of most of the scanned images for both groups were scored as 3 or 4 (on a five-point scale). The radiation dose and the volume of CM were significantly higher in Group A (303.05 ± 110.95 mGy) (100 mL) than in Group B (239.46 ± 101.12 mGy) (50 mL). The radiation dose and volume of CM were significantly reduced in CTA following the HR-based protocol. The personalized administration of CM also simplified the scanning process.

D-14 | Efficacy of contrast Diastolic Hyperemia-Free Ratio (Contrast - DFR) in comparison to coronary Fractional Flow Reserve with adenosine and Diastolic Hyperemia-Free Ratio (DFR)

BackgroundCoronary fractional flow reserve (FFR) is recommended as the gold standard method in evaluating intermediate coronary stenosis. Various methodologies have been reported using Diastolic Hyperemia – Free Ratio (DFR) and Instantaneous wave - free ratio.AimTo compare the contrast induced Pd/Pa ratio (DFR) with DFR and FFR.MethodsWe enrolled 19 consecutive patients with 20 intermediate lesions who underwent Diastolic pressure ratio measurement using DFR baseline Pd/Pa was calculated. A single contrast medium injection of 6 ml (3 ml/s) was performed manually and a Contrast DFR was measured within 10 seconds of injection.Following which coronary FFR measurement was performed using intravenous injection of adenosine to induce maximal hyperemia using 140 mcg/kg/min for 2 minutes and when it was ≤ 0.80, the intermediate lesion was considered as significant.Abnormal DFR was defined as cut off value 0.89, Contrast DFR as cut off value 0.80, FFR as cut off value 0.80.ResultsDiastolic pressure ratio was identified as significant in 10 lesions of 20 (50%) with a mean of 0.89 (range:0.66-1). The Contrast DFR was identified significant in 9 lesions of 20 (45%) with a mean of 0.80 (range of 0.67-0.97). FFR was abnormal in 9 lesions of 20 (45%) with a mean of 0.82 (range 0.63-0.97). A substantial positive correlation between FFR and contrast DFR values was detected (0.76) versus comparing correlation of DFR versus FFR (0.59).ConclusionsDisclosuresT. Raxwal Nothing to disclose. D. Parekh Nothing to disclose. R. M. Akel Nothing to disclose. BackgroundCoronary fractional flow reserve (FFR) is recommended as the gold standard method in evaluating intermediate coronary stenosis. Various methodologies have been reported using Diastolic Hyperemia – Free Ratio (DFR) and Instantaneous wave - free ratio. Coronary fractional flow reserve (FFR) is recommended as the gold standard method in evaluating intermediate coronary stenosis. Various methodologies have been reported using Diastolic Hyperemia – Free Ratio (DFR) and Instantaneous wave - free ratio. AimTo compare the contrast induced Pd/Pa ratio (DFR) with DFR and FFR. To compare the contrast induced Pd/Pa ratio (DFR) with DFR and FFR. MethodsWe enrolled 19 consecutive patients with 20 intermediate lesions who underwent Diastolic pressure ratio measurement using DFR baseline Pd/Pa was calculated. A single contrast medium injection of 6 ml (3 ml/s) was performed manually and a Contrast DFR was measured within 10 seconds of injection.Following which coronary FFR measurement was performed using intravenous injection of adenosine to induce maximal hyperemia using 140 mcg/kg/min for 2 minutes and when it was ≤ 0.80, the intermediate lesion was considered as significant.Abnormal DFR was defined as cut off value 0.89, Contrast DFR as cut off value 0.80, FFR as cut off value 0.80. We enrolled 19 consecutive patients with 20 intermediate lesions who underwent Diastolic pressure ratio measurement using DFR baseline Pd/Pa was calculated. A single contrast medium injection of 6 ml (3 ml/s) was performed manually and a Contrast DFR was measured within 10 seconds of injection. Following which coronary FFR measurement was performed using intravenous injection of adenosine to induce maximal hyperemia using 140 mcg/kg/min for 2 minutes and when it was ≤ 0.80, the intermediate lesion was considered as significant. Abnormal DFR was defined as cut off value 0.89, Contrast DFR as cut off value 0.80, FFR as cut off value 0.80. ResultsDiastolic pressure ratio was identified as significant in 10 lesions of 20 (50%) with a mean of 0.89 (range:0.66-1). The Contrast DFR was identified significant in 9 lesions of 20 (45%) with a mean of 0.80 (range of 0.67-0.97). FFR was abnormal in 9 lesions of 20 (45%) with a mean of 0.82 (range 0.63-0.97). A substantial positive correlation between FFR and contrast DFR values was detected (0.76) versus comparing correlation of DFR versus FFR (0.59). Diastolic pressure ratio was identified as significant in 10 lesions of 20 (50%) with a mean of 0.89 (range:0.66-1). The Contrast DFR was identified significant in 9 lesions of 20 (45%) with a mean of 0.80 (range of 0.67-0.97). FFR was abnormal in 9 lesions of 20 (45%) with a mean of 0.82 (range 0.63-0.97). A substantial positive correlation between FFR and contrast DFR values was detected (0.76) versus comparing correlation of DFR versus FFR (0.59). Conclusions DisclosuresT. Raxwal Nothing to disclose. D. Parekh Nothing to disclose. R. M. Akel Nothing to disclose. T. Raxwal Nothing to disclose. D. Parekh Nothing to disclose. R. M. Akel Nothing to disclose.

Single rotation CTA of extracranial carotids integrated with cerebral CTP provides sufficient quality for decision making in patients with ischaemic stroke.

Large volume computed tomography scanners with 16 cm Z-axis single rotation coverage enable joggle-mode scanning of cerebral computed tomography perfusion and single rotation computed tomography angiography of cervical arteries. Our study aims to evaluate the feasibility of scanning cervical arteries, acquired with single rotation computed tomography angiography during computed tomography perfusion in ischaemic stroke patients. A total of 143 patients were scanned with a single contrast medium injection of 60 ml. Hounsfield units of the cervical arteries and veins were objectively measured and carotid bifurcations were subjectively reviewed. The incidence of artefacts and supra-aortic vessel coverage was recorded. Single rotation computed tomography angiography of the neck demonstrated supra-aortic vessels to their origins in 58 (40.6%) patients. Ninety-nine per cent (1140/1152) of arterial segments were adequately opacified (≥150 Hounsfield units). Arteries were adequately contrasted compared to veins in 81.3% (915/1126) of segments. However, the opacification was reversed in 14.0% (158/1126) of segments, indicating a delayed timing of acquisition; 95.5% (273/286) of carotid bifurcations were of good image quality. Measurement of internal carotid artery stenosis in single rotation computed tomography angiography according to the North American Symptomatic Carotid Endarterectomy Trial correlated well with digital subtraction angiography (R=0.87, P<0.05). Significant artefacts resulted from metal/dental implants (10.5%), contrast in central veins (7.7%) and the shoulder region (4.9%). Single rotation computed tomography angiography of the neck incorporated into cerebral computed tomography perfusion with single contrast medium administration revealed adequate image quality for further decision-making in our patient sample. The main drawbacks were inadequate coverage of supra-aortic arteries and possible delay in timing of the joggle.

Combined Coronary CT Angiography and Evaluation of Access Vessels for TAVR Patients in Free-Breathing with Single Contrast Medium Injection Using a 16-cm-Wide Detector CT

To investigate the feasibility of combining coronary computed tomography (CT) angiography (CCTA) and CTA to evaluate access vessels for transcatheter aortic valve replacement (TAVR) patients in free-breathing and with single contrast medium injection using a 16-cm-wide detector CT. One hundred and twenty-one consecutive patients (73.33 ± 6.43 years) referred for TAVR underwent a serious CT scans in free-breathing after one contrast injection: ECG-triggered one-heartbeat axial CCTA, followed by non-ECG-gated neck, thoracic, and abdominal CTA. Patient weight-dependent contrast dose volume at 1.0 mL/kg was used. CT attenuation values of the coronary, neck, aortic, iliac, and femoral arteries were measured and their image quality was evaluated with a 4-point score method. Stenosis (≥50%) in CCTA was evaluated using invasive coronary angiography result as a reference standard. Radiation and contrast doses were assessed. The total dose-length-product for the entire examination was 411.4 ± 91.2 mGy.cm, and the total contrast dose was 57.3 ± 9.9 mL. There were adequate attenuations (>400 HU) in all arteries, and the peripheral access vessels and aortic annulus were evaluable in all patients. In neck CTA, 5 patients had vascular tortuosity, 6 patients had aberrant arteries and there were 212 plaques and 13 severe stenoses among the patients. In CCTA, on the per-segment, per-vessel, and per-patient analysis, CCTA showed a sensitivity and negative predictive value of (95% and 99%), (95% and 99%), and (96% and 98%), respectively, for the entire patient cohort, and (92% and 98%), (92% and 98%), and (88% and 93%), respectively, for patients with atrial fibrillation or heart rate higher than 75 beats. It is feasible to perform a combined CCTA and CTA for evaluating access vessels for TAVR patients in free-breathing with single contrast injection. This approach generates acceptable image quality for all vessels and a high negative predictive value in excluding coronary artery disease with relatively low radiation and contrast doses.

CT angiography of the lower extremity and coronary arteries using 256-section CT: a preliminary study

To investigate the possible use of a 256-section computed tomography (CT) prospective electrocardiography (ECG)-gated wide volume scanning protocol for combined angiography of the lower extremity and coronary arteries, after a single injection of contrast medium, in patients with lower extremity peripheral arterial disease (PAD). Thirty-four patients with suspected PAD underwent CT angiography (CTA) with a prospective ECG-gated protocol that covered the level of the tracheal bifurcation to the foot sole. Digital subtraction angiography (DSA) of the lower extremity arteries was performed on patients requiring therapeutic intervention. Image quality and stenosis of the coronary and lower extremity arteries were assessed. A total of 93.1% of the coronary segments were adequate for diagnosis. 17 (50%) patients showed coronary artery stenosis ≥50%. A total of 95.8% of the lower extremity arterial segments were adequate for diagnosis. Twenty-eight patients with severe lower extremity arterial stenosis or occlusion underwent DSA. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CTA for the detection of significant lower arterial stenosis (≥50%) was 94.8%, 97.2%, 95.3%, 96.9%, and 96.3%, respectively. Using the prospective ECG-gated wide volume CTA protocol, images of the coronary and lower extremity arteries suitable for diagnosis can be acquired simultaneously after a single injection of contrast agent. In addition to accurately diagnosing PAD, combined angiography may be used to screen for coronary heart disease in patients with PAD.

Simultaneous bilateral magnetic resonance angiography to evaluate thoracic outlet syndrome.

This paper presents a new magnetic resonance angiography (MRA) protocol for the evaluation of thoracic outlet syndrome (TOS) that allows for a separate assessment of veins and arteries while using a single, simultaneous and bilateral (SB-MRA) single contrast injection, valid for both abduction and adduction acquisitions. From 2009 to 2013 we performed 38 MRA studies for clinically suspected TOS (13 M, 25 F; mean age, 35.9years; σ=11.13). Twin peripheral 20G intravenous catheters were placed in a cubital vein in both arms and connected to a single power injector by two lines joined with a connector. A 3T MR system with a wide gantry was used. Two groups of four radiologists assessed all the images. Group A judged the full examinations, Group B had only the late acquisitions. Differences were evaluated using the Chi square test. TOS was confirmed only after integration with the clinical history. Seventeen (45%) patients were diagnosed with predominant venous TOS (VTOS), nine (24%) with predominant arterial TOS (ATOS) and 12 (32%) had an indeterminate or nonvascular condition. Group A radiologists identified significantly more VTOS than group B (p=0.049). Interobserver agreement was very high. SB-MRA is a safe and reliable protocol for the study of TOS. It provides a supplementary early acquisition that allows for separate assessment of veins and arteries, permits the investigation of the collateral venous flow with a single injection of contrast material and provides a higher diagnostic power for VTOS. SB-MRA is helpful for the diagnosis of TOS of vascular origin.

Whole‐body MR angiography: First experiences with the new TimCT technology with single contrast injection

To assess image quality, presence of artifacts, arterial stenosis, and interobserver agreement of Tim-CT in assessment of the arterial system using contrast-enhanced whole-body-MRA (CE-Wb-MRA) with a single contrast-medium injection in patients with arteriosclerosis. The retrospective study included 18 patients (mean age, 68 years). A total of 468 arteries were evaluated. CE-Wb-MRA was performed using Tim-CT technology on a 1.5 Tesla (T) MRI after injecting a single dose of Vasovist. Evaluations were independently performed by two radiologists. The arterial system was divided into seven anatomic locations. Each radiologist assessed the image quality, degree of artifacts, and arterial stenosis in different locations. All Wb-MRA examinations were technically successful. Image quality: 28.42% arteries were excellent, 29.17% were good, 22.54% were satisfactory, 9.40% were poor, and 5.13% of insufficient quality. Occurrence of artifacts: 37.25% were free of artifacts, 49.44% minimal artifacts not affecting diagnosis, and 13.31% strong artifacts not permitting a diagnosis. A total of 60.00% arteries showed no stenosis, 8.76% were ≤50% stenotic, 5.17% were 51-75% stenotic, 4.38% were 76-99%, and 8.54% total occlusion. The interobserver agreement was good for supra-aortic, pelvic, and upper and lower leg regions. CE-Wb-MRA using the TimCT technology and with a single contrast injection is a feasible tool for whole-body MRA.

Contrast enhanced spectral mammography: better than MRI?

The initial method developed for contrast enhanced mammography used temporal acquisitions of high-energy images before and after intravenous injection of iodinated contrast medium [1–4]. The patient had to be primarily positioned for breast compression, using minimal pressure not to alter diffusion of contrast agent. A baseline image (mask) was obtained before injection. Following contrast administration, serial images were acquired over several minutes. Logarithmic subtraction of pre and post-contrast images was applied. Initial experience with such dynamic imaging showed the clinical feasibility of the technique. Further work investigated the diagnostic benefits offered by this modality over conventional mammography, showing a gain in sensitivity for the detection of cancer particularly in dense breasts [4]. The technique, however, proved sensitive to motion artifacts. It also posed the issue of the additional radiation exposure applied for an examination limited to one breast at a time in a single projection view. The second method developed for contrast enhanced mammography was based on dual energy acquisition. Physical and clinical research currently focuses on this technology also referred to as spectral imaging or contrast enhanced spectral mammography (CESM). To allow visualization of low concentration of iodine with only a modest increase in radiation exposure, the x-ray spectrum delivers energies just above the K-edge of iodine (33.2 keV) while using a high voltage range of 45–50kVp [5]. In that setting the patient receives contrast administration first and then is positioned for mammography with normal compression of the breast. A typical protocol goes from obtaining the mediolateral oblique (MLO) view on one breast – typically 2 min after the start of injection – to the MLO view on the other breast, then from the craniocaudal (CC) view on the first side – 4 min after the start of injection – to the CC view on the other side. For each view, a pair of low and highenergy images is acquired. The two images are combined so that the areas of iodine enhancement are highlighted from background parenchyma. Two views of both breasts can be obtained after a single injection of contrast medium.

Three-Dimensional Guided Renal Denervation to Treat Drug-Resistant Arterial Hypertension in a Patient With Renal Insufficiency

HomeHypertensionVol. 60, No. 4Three-Dimensional Guided Renal Denervation to Treat Drug-Resistant Arterial Hypertension in a Patient With Renal Insufficiency Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissionsDownload Articles + Supplements ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toSupplemental MaterialFree AccessLetterPDF/EPUBThree-Dimensional Guided Renal Denervation to Treat Drug-Resistant Arterial Hypertension in a Patient With Renal Insufficiency Thorsten Lewalter and Turgut Brodherr Thorsten LewalterThorsten Lewalter Isar Heart Center Munich, Munich, Germany Search for more papers by this author and Turgut BrodherrTurgut Brodherr Isar Heart Center Munich, Munich, Germany Search for more papers by this author Originally published20 Aug 2012https://doi.org/10.1161/HYPERTENSIONAHA.112.201467Hypertension. 2012;60:e33Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: January 1, 2012: Previous Version 1 To the Editor:A 68-year–old diabetic women was transferred to our department for renal denervation to treat drug-resistant arterial hypertension. A known diabetic nephropathy deteriorated after an abdominal computed tomography scan in the external hospital with an increase of the serum creatinine (baseline, 1.3 mg/dL; 5 days after computed tomography, 2.1 mg/dL; at admission to our hospital, 1.4 mg/dL). To reduce or even eliminate the amount of necessary contrast medium during the denervation procedure we decided to perform a 3D guided ablation procedure.For this purpose, the external abdominal computed tomography scan was used to reconstruct the 3D anatomy of the renal arteries. The impedance-based NavX system (St Jude), used routinely in arrhythmia ablation, was used to create a virtual anatomy of both renal arteries by touching the vessel walls. For image fusion, critical anatomic landmarks like, for example, an orifice of the renal arteries or areas of vessel bifurcation, were determined by comparing the position of the catheter in the native x-ray and the 3D image based on computed tomography anatomy. A decapolar steerable electrode catheter in the renal venous system served as the local reference catheter (Figure A and B, video).Download figureDownload PowerPointFigure. Anterolateral view (A) and posterior view (B) of the 3D image of the renal artery (red), the renal vein (blue), and kidney parenchyma (gray). The reference decapolar catheter is positioned in a side branch of the renal vein. The ablation catheter can be located in the proximal portion of the renal artery. The green dots indicate ablation spots.To perform the ablation, a cooled tip 7F quadripolar radiofrequency ablation (IBI/St Jude) catheter with a flow of 17 mL/min and a maximum of 10 watts was used in a power-controlled mode (IBI/St Jude RF generator). In the right renal artery 11 ablation points and in the left 13 ablation points were delivered in a spiral manner from the distal until the proximal portion of both renal arteries. To check the distal catheter position once for the fusion process, a single contrast medium injection was performed in each renal vein (7 mL for the left and 8 mL for the right), leading to a total contrast medium volume of 15 mL for the entire procedure. To reduce the risk of vasospasm, we performed the procedure in deep sedation (propofol infusion). No creatinine increase could be detected after the ablation procedure. A postprocedural Doppler sonography of both renal arteries revealed no evidence for a stenotic process. At 3 months after the procedure, a drop in the mean systolic blood pressure of 9 mm Hg and in the mean diastolic pressure of 4 mm Hg in a 24-hour measurement could be documented.To our knowledge, this is the first report about a cooled tip renal denervation using a 3D nonfluoroscopic guiding system. This approach allows an ablation requiring only a minimal amount of contrast medium. Even a procedure without any contrast medium appears feasible with this technique. Therefore, this approach is of special interest in patients with drug-resistant arterial hypertension and concomitant renal insufficiency with the aim of reducing their exposure to contrast medium to a minimum.Thorsten LewalterTurgut BrodherrIsar Heart Center MunichMunich, GermanyFootnotesLetters to the Editor will be published, if suitable, as space permits. They should not exceed 1000 words (typed double-spaced) in length and may be subject to editing or abridgmentThe online-only Data Supplement is available with this article at http://hyper.ahajournals.org/lookup/suppl/doi:10.1161/HYPERTENSIONAHA.112.201467/-/DC1. Previous Back to top Next FiguresReferencesRelatedDetailsCited By Tölle M and van der Giet M (2013) Renale Denervation als Therapieoption, CardioVasc, 10.1007/s15027-013-0022-1, 13:1, (38-44), Online publication date: 1-Feb-2013. Xiao Y, Zhou S and Liu Q (2012) Ablation Points of Renal Sympathetic Denervation: The More, the Better?, Hypertension, 60:6, (e47-e47), Online publication date: 1-Dec-2012. October 2012Vol 60, Issue 4 Advertisement Article InformationMetrics © 2012 American Heart Association, Inc.https://doi.org/10.1161/HYPERTENSIONAHA.112.201467PMID: 22914794 Originally publishedAugust 20, 2012 PDF download Advertisement SubjectsArrhythmiasCatheter Ablation and Implantable Cardioverter-DefibrillatorHypertensionTreatment

Time‐resolved dual‐station calf–foot three‐dimensional bolus chase MR angiography with fluoroscopic tracking

To refine, adapt, and evaluate the technical aspects of fluoroscopic tracking for generating dual-station high-spatial-resolution MR angiograms of the calves and feet using a single injection of contrast material. Nine subjects (seven healthy volunteers followed by two patients) were imaged using a two-station calf-foot three-dimensional time-resolved bolus chase MR angiography protocol which provided <1.0 mm(3) spatial resolution throughout and 2.5- and 6.6-s frame times at the calf and foot stations, respectively. Real-time reconstruction of calf station time frames allowed visually guided triggering of table advance to the foot station. The studies were independently read and scored by two radiologists in six image quality categories. On average, overall diagnostic quality at the calf and foot stations was good-to-excellent, the calf arteries and all but the smallest foot arteries had good-to-excellent signal and sharpness, artifact and venous contamination were minor, and signal continuity across the inter-station interface was good. The feasibility of fluoroscopic tracking has been demonstrated as an efficient approach for high spatiotemporal imaging of the arteries of the calves and feet with good-to-excellent diagnostic quality and low degrading venous contamination.

Ultrafast Whole-Body MR Angiography with Two-dimensional Parallel Imaging at 3.0 T: Feasibility Study

The study was approved by the local ethics committee, and informed consent was provided by all participants prior to the examination. The aim of the study was to assess the feasibility of whole-body three-dimensional (3D) contrast material-enhanced magnetic resonance (MR) angiography with parallel imaging in the phase- and section-encoding directions (ie, integrated parallel acquisition technique [iPAT(2); Siemens, Erlangen, Germany]) for all anatomic imaging stations in combination with a single injection of contrast material. Whole-body contrast-enhanced MR angiography was performed in 23 patients at 3.0 T. Images were evaluated by two independent observers for quality on a four-point scale (where a score of 1 indicated poor image quality and a score of 4, excellent image quality); signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were calculated for representative vessel regions in each station. Mean image quality scores were 3.13 +/- 1.15 (standard deviation) and 3.17 +/- 1.14 for observers 1 and 2, respectively (kappa = 0.81). Signal intensity measurements revealed mean SNR values between 36.2 +/- 8.0 and 56.2 +/- 17.7 and mean CNR values between 29.0 +/- 7.4 and 48.2 +/- 15.7. The data suggest that contrast-enhanced MR angiography with iPAT(2) is feasible for whole-body applications and allows acquisition of 3D data sets with adequate spatial resolution within short measurement times, facilitating a single injection of contrast material.

Time-Resolved 3D MR Angiography with Parallel Imaging for Evaluation of Hemodialysis Fistulas and Grafts: Initial Experience

We optimized a time-resolved 3D contrast-enhanced MR angiography sequence with integrated parallel imaging technique that can provide a large field of view with high temporal and spatial resolution, by which the hemodialysis access and the entire course of the inflow and outflow vessels can be imaged at a single anatomic station. Our objective was to evaluate the feasibility and usefulness of this method in the evaluation of patients referred for possible abnormalities in hemodialysis access. Time-resolved contrast-enhanced 3D MR angiography with parallel imaging has the potential to provide a rapid and comprehensive evaluation for the surveillance and diagnosis of hemodialysis access malfunctions. This technique may function as an important complement to conventional digital subtraction angiography and may be able to help guide medical management. The MR angiography protocol we present is a noninvasive, versatile, and time-efficient technique, without the need of direct graft puncture or flow interruption, and can be performed using a single injection of contrast material at a single station.

Quand, comment et pourquoi réaliser une imagerie des artères des membres inférieurs ?

Noninvasive screening of lower limb arterial disease has long been performed using color Doppler ultrasonography, whereas surgical or endovascular treatment planning relied on conventional angiography. With continued improvements of noninvasive imaging modalities, it is now possible to image the entire lower limb vasculature without arterial catheterization. Multidetector row helical CT angiography has the advantage of visualizing the arterial lumen and arterial wall calcifications, and nephrotoxicity is reduced by decreasing amounts of contrast medium. Three-dimensional MR angiography is a safe procedure, with high contrast sensitivity, and has recently benefited from step table technology that allows a single injection of contrast medium. The literature shows that both helical CT and MR angiography have high levels of accuracy, but outcome studies of their respective role in the setting of acute and chronic lower limb ischemia are lacking. These noninvasive techniques should play a major role in two main situations: first, in critical ischemia where therapeutic planning should ideally be achieved non invasively; second, in the follow-up of treated patients presenting with recurrent ischemia.

Development of rotational digital angiography system — clinical value in acute pulmonary thromboembolism

A rotational digital angiography system was newly developed by authors. During the rotation, a pulse exposure is done at every 1.25° by computer control, so that 288 different projectional images can be acquired following a single injection of contrast medium. Because rotational image data can be easily reconstructed to 3-D images, more useful diagnostic informations are obtained. Rotational digital angiography was performed for 15 patients with acute pulmonary thromboembolism, and massive thromboemboli were revealed in all patients. The diagnostic usefulness of this new system has also proven to be improved in the interventional procedures. At the appropriate angle, the thrombosed vessels were clearly distinguished. Thus, as the tip of the catheter was advanced to the target site, the thrombosed lesion could be exclusively treated by interventional techniques. The device has, therefore, been found to be of great value in the diagnosis and intervention of acute pulmonary thromboembolism.

Diagnosis of renal vascular disease with MR angiography.

Renal magnetic resonance (MR) angiography allows accurate evaluation of patients suspected to have renal artery stenosis without the risks associated with nephrotoxic contrast agents, ionizing radiation, or arterial catheterization. Other applications of renal MR angiography are mapping the vascular anatomy for planning renal revascularization, planning repair of abdominal aortic aneurysms, assessing renal bypass grafts and renal transplant anastomoses, and evaluating vascular involvement by renal tumors. A variety of pulse sequences provide complementary information about kidney morphology, arterial anatomy, blood flow, and renal function and excretion. Three-dimensional gadolinium-enhanced MR angiography can be combined with several other sequences to produce a comprehensive approach to renal MR angiography. This comprehensive approach is designed to allow hemodynamic characterization of renal artery stenosis with a single MR imaging examination that can be easily completed in 1 hour. Three-dimensional gadolinium-enhanced MR angiography demonstrates the renal arteries along with the abdominal aorta, iliac arteries, and mesenteric arteries in a 20-30-second acquisition that can be performed during breath holding. Numerous projections are reconstructed from a single three-dimensional volume of data acquired with a single injection of contrast material to obtain perpendicular and optimized views of each renal artery.

Development of rotational digital angiography and new cone-beam 3D image: Clinical value in vascular lesions

Despite the rapid improvement of new imaging modalities such as CT, MRI and echography techniques, angiography still plays the role of gold standard for the diagnosis of vascular lesions. The main reason for this dependence on angiography is its superiority in the S/N ratio and spatial resolution. However, the essential problem remained in angiography, even in modern DSA, is that, after a single injection of contrast medium, imaging is done from only one or two projections. Serial filming by rotating method of the X-ray unit around the longitudinal axis of the target organ will theoretically solve the above problem. This method has been documented at times for cerebral angiography since the report of Cornelis et al. [1], while the rotational digital X-ray system sufficient to various human organs has been described by few authors [2, 3]. The aim of this paper is to discuss the value of the new system from the clinical view.

Myocardial Contrast Echocardiography in Acute Myocardial Infarction Using Aortic Root Injections of Microbubbles in Conjunction With Harmonic Imaging: Potential Application in the Cardiac Catheterization Laboratory

Objectives. The aim of this study was to evaluate myocardial contrast echocardiography using aortic root injections with harmonic imaging in experimental acute myocardial infarction to determine the potential of this approach in the cardiac catheterization laboratory.Background. It would be desirable to have an adjunctive procedure that could evaluate myocardial perfusion at the time of cardiac catheterization in patients with acute myocardial infarction. A single injection of contrast medium in the aortic root would provide complete information on myocardial perfusion in a cross section of the heart. High quality images would provide on-line assessment of myocardial perfusion without recourse to image processing. These data could be very valuable for determining patient management.Methods. Perfusion defects on myocardial contrast echocardiography were measured during coronary occlusion and reflow, using fundamental and harmonic imaging in both continuous and intermittent modes in nine open chest dogs. These defects were compared with risk area on technetium-99m autoradiography and infarct size on tissue staining.Results. Whereas harmonic imaging increased myocardial video intensity by more than twofold (p < 0.001) compared with fundamental imaging after aortic root injection of contrast medium, intermittent imaging was not superior to continuous imaging. The improved signal to noise ratio of harmonic imaging allowed on-line definition of risk area (r = 0.98) and infarct size (r = 0.93) without recourse to off-line processing. Similar results could be obtained with fundamental imaging only after off-line processing.Conclusions. Aortic root injections of contrast medium coupled with harmonic imaging can be used to provide accurate on-line assessment of risk area and infarct size during acute myocardial infarction. These results have important implications for the catheterization laboratory.(J Am Coll Cardiol 1997;29:207–16)>

Neuroradiological applications of a new system of stereoscopic biplane digital subtraction angiography.

A stereoscopic biplane digital subtraction angiography (DSA) system was developed, capable of obtaining frontal and lateral projections simultaneously during a single injection of contrast medium. This new system combines the advantages of both biplane and stereoscopic single-plane DSA, and permits high-quality neuroangiography.

Visualization of blood-brain barrier disruption on MR images of cats with acute cerebral infarction: value of administering a high dose of contrast material.

The detection of blood-brain barrier disruption in patients with cerebral infarction by means of contrast-enhanced MR images improves the specificity of diagnosis, enables lesion dating, and on occasion improves lesion detection. Accordingly, we performed a study to determine the extent of visualization of disruption of the blood-brain barrier on contrast-enhanced MR images, with specific attention to contrast dose, in a cat model of acute cerebral infarction. We used doses of 0.1 and 0.3 mmol/kg of a gadolinium chelate, gadoteridol, which is characterized by extracellular distribution and renal excretion, and was approved by the Food and Drug Administration for clinical use at these doses. Blood flow in the middle cerebral artery was occluded unilaterally in seven cats for 1 hr, followed by 4 hr of reperfusion. T2- and T1-weighted MR images were obtained before the injection of contrast material. After injection, the time course of enhancement was observed for 1 hr by repeated sequential acquisition of T1-weighted images. Five cats received an initial injection of 0.1 mmol/kg of contrast material, supplemented 33 min later by 0.2 mmol/kg (cumulative dose, 0.3 mmol/kg). Two cats received a single injection of contrast material, either 0.1 or 0.3 mmol/kg. The images were reviewed in a prospective fashion by a single observer, who was blinded to the dose of contrast material and the timing of image acquisition, in order to detect abnormal contrast enhancement. Changes in single intensity were quantified by region-of-interest measurements. Enhancement at 4 and 13 min, respectively, after injection of contrast material was 25 +/- 10% and 38 +/- 7% with 0.1 mmol/kg, vs 80 +/- 12% and 100 +/- 15% with 0.3 mmol/kg (n = 5). The difference between doses was statistically significant (p < .002) for all time points. Abnormal contrast enhancement was visible in three of six cats that received 0.1 mmol/kg and in all cats that received 0.3 mmol/kg. By 13 min after injection, enhancement had peaked with a dose of 0.1 mmol/kg and was within 20% of maximum with a dose of 0.3 mmol/kg. Detection of disruption of the blood-brain barrier in acute cerebral infarction in cats is improved when high doses (0.3 mmol/kg) of contrast material are used. Disruption may not be visualized when 0.1 mmol/kg, the currently accepted standard dose, is used.

Peripheral DSA with automated stepping

Peripheral digital angiography can be applied with automated stepping and in digital subtracted technique to evaluate the complete lower extremities angiographically with one single injection of contrast medium. Altogether 25 DSA-examinations were compared with non-subtracted technique. By DSA-technique additional series could be reduced to only those, where significantly different flow in both extremities necessitated different timing as known from conventional angiography. DSA-technique with automated stepping may in the future totally replace conventional angiography of the peripheral arteries.