Intra-arterial Contrast Injection Research Articles

Contrast-Enhanced Angiographic Cone-Beam CT of Cerebrovascular Stents: Experimental Optimization and Clinical Application

With modern imaging techniques, visualization of neurovascular stents remains challenging. We present a method for contrast-enhanced C-arm CBCT that provides detailed and simultaneous visualization of neurovascular stents and host arteries. CBCT was performed with a rotational angiography system by acquiring 620 projection frames over a 200° arc at 80 kVp and a total of 260 mAs. A superselective intra-arterial contrast injection protocol was optimized in swine experiments and implemented in 57 clinical examinations. High-resolution 3D reconstructions were evaluated by 3 blinded interventional neuroradiologists. Reviewers rated the images by answering questions related to both the quality of the stent and artery visualization and the clinical utility of the images. Raw agreement statistics, ICC, and κ statistics were computed for the questionnaire results. Of 57 clinical evaluations, 5 were not evaluated due to the use of large balloon-mounted stents (n = 4) and a failed contrast injection (n = 1). In 50 of 52 evaluated examinations, the reviewers agreed that simultaneous stent and vessel visualization was of diagnostic quality. There was strong agreement that stent-vessel wall apposition could be assessed (κ = 0.79). CBCT detected contrast filling defects (κ = 0.85) and vascular calcification (κ = 0.68). Artifacts resulting from the aneurysm coil mass impaired the delineation of adjacent structures (κ = 0.72). We have developed a technique that enables simultaneous clinically useful imaging of neurovascular stents and their host arteries that is unobtainable with other current imaging modalities. Further improvements are required to reduce artifacts from large coil masses due to x-ray scattering.

Modern meningioma imaging techniques

Steady improvements in imaging modalities have enabled a new realm of capabilities in the identification and assessment of meningiomas. The cross-sectional imaging modalities, MRI and CT, have improved in resolution and fidelity. These modalites now provide not only improved structural information but also insights into functional behavior. MRI has, in particular, proven to have powerful capabilities in evaluating meningiomas because of the ability to assess soft tissue characteristics such as diffusion and vascular supply information, such as perfusion. Recent investigational advances have also been made using a combination of X-ray fluoroscopy for selective catheterization followed by MR perfusion measurement performed with intra-arterial injection of contrast. Together all these modalities provide the radiographer with powerful capbilities for evaluating meningiomas.

Iodixanol Versus Low-Osmolar Contrast Media for Prevention of Contrast Induced Nephropathy

Background— Contrast-induced nephropathy (CIN) is associated with significant morbidity and mortality. The objective of our meta-analysis was to assess the efficacy of iodixanol compared with low-osmolar contrast media (LOCM) for prevention of CIN. Methods and Results— We searched MEDLINE, the Cochrane Central Register of Controlled Trials, and internet sources of cardiology trial results for individual and relevant reviews of randomized, controlled trials, for the terms contrast media, contrast nephropathy, renal failure, iodixanol, Visipaque, and low-osmolar contrast media. All studies reported an incidence rate of CIN for each study group; there was no restriction on the definition of CIN. There were no restrictions on journal type or patient population. Overall, 36 trials were identified for analysis of aggregated summary data on 7166 patients; 3672 patients received iodixanol and 3494 patients received LOCM. Overall, iodixanol showed no statistically significant reduction in CIN incidence below that observed with heterogeneous comparator agents ( P =0.11). Analysis of patient subgroups revealed that there was a significant benefit of iodixanol when compared with iohexol alone (odds ratio, 0.25; 95% confidence interval, 0.11 to 0.55; P <0.001) but not when compared with LOCM other than iohexol or with other ionic dimers or among patients receiving intra-arterial contrast injections or among patients undergoing coronary angiography with or without percutaneous intervention. Conclusions— Analysis of aggregated summary data from multiple randomized, controlled trials of iodixanol against diverse LOCMs for heterogeneous procedures and definitions of CIN show an iodixanol-associated reduction that is suggestive but statistically nonsignificant.

P-007 Initial experience with a combined multi-detector row CT and a biplane angiography suite with a single interactive table for the evaluation and treatment of vascular disease involving the head and neck

Introduction and purposeThe purpose of this study is to present our initial experience with the usefulness of a combined multi-detector row CT and biplane angiographic system with a single interactive...

Ultra-Low-Dose Intra-Arterial Contrast Injection for Iliofemoral Computed Tomographic Angiography

This study sought to evaluate the feasibility of using ultra-low-dose intra-arterial contrast injection for iliofemoral computed tomographic (CT) angiography to follow diagnostic cardiac catheterization. Cardiovascular interventions such as percutaneous aortic valve replacement require transfemoral delivery of large-bore intra-arterial catheters; therefore, pre-procedural assessment of aortoiliofemoral anatomy is important. CT angiography is ideal for this purpose but requires a large volume of intravenous contrast. Consecutive patients requiring evaluation of aortoiliofemoral anatomy underwent conventional anteroposterior projection iliac angiography during cardiac catheterization. A pigtail catheter was left in situ in the infrarenal abdominal aorta, and patients were transferred to the CT suite. Subsequently, 10 to 15 ml of contrast diluted with normal saline was injected intra-arterially via the pigtail catheter while a spiral CT of the abdomen and pelvis was acquired. Conventional angiographic and CT images were analyzed independently to assess suitability for large-bore (7-mm-diameter)intra-arterial catheter access. Excellent CT image quality was achieved in 34 of 37 patients (92%). The mean contrast dose for CT was 12 +/- 2 ml. In 9 patients (24%), CT changed the assessment of femoral access feasibility. Furthermore, in another 7 patients (19%), unfavorable anatomy as shown by CT directed the avoidance of a particular side. Overall, CT findings altered the interventional approach in 16 patients (43%). There was no significant deterioration detected in renal function after coronary and CT angiography (estimated glomerular filtration rate 54.8 +/- 3.8 ml/min before 53.3 +/- 3.9 ml/min after, p = 0.55). High-quality aortoiliofemoral CT angiography can be obtained with a technical success rate of >90% using 10 to 15 ml of contrast injected via a catheter in the abdominal aorta, and offers an alternative to conventional X-ray or CT angiography with high-volume intravenous contrast injection.

Multi-Detector Row CT Angiography with Direct Intra-Arterial Contrast Injection for the Evaluation of Neurovascular Disease: Technique, Applications, and Initial Experience

The purpose of this study was to evaluate the usefulness of 64-section multi-detector row CT angiography (CTA) with direct intra-arterial contrast injection (IA-CTA) for the evaluation of neurovascular disease. This technique was used in 11 patients at our institution. All studies were technically successful, and there were no complications. Small vascular malformations were mapped easily on high-resolution IA-CTA images, enabling microsurgical resection or stereotactic radiosurgery. In a similar fashion, additional morphologic features were revealed on IA-CTA images not seen on standard 2D and 3D digital subtraction angiography. Of 11 patients undergoing IA-CTA, 7 patients had further anatomic clarity of the small arteriovenous fistula/malformation and 4 patients had changes in the treatment plan on the basis of the IA-CTA findings.

Real‐time catheter‐directed MRA with effective background suppression and persistent rendering

To develop an imaging and visualization technique for real-time magnetic resonance angiography (rtMRA) fully integrated with a real-time interactive imaging environment on a clinical MR scanner. Intraarterial injections of contrast agent and imaging processing techniques were employed for rapid catheter-directed assessment of vessel patency and regional tissue perfusion. Operators can image multiple thin slices to maximize anatomic detail or use thick slice or projection imaging to maximize vessel coverage. Techniques in both pulse sequence and image processing were employed to ensure background suppression. Accumulation of maximum pixel values allows persistent display of bolus signal as it passes through the vessels and into tissues. Automatic brightness adjustment was used to ensure visibility at all stages of bolus passage. Experimental intraarterial rtMRA of coronary, renal, and carotid arteries show that vessel trajectories and perfusion territories are well visualized in swine. Switching between standard real-time imaging and rtMRA imaging after contrast injection was easy to perform during a procedure without stopping the scanner. The proposed technique facilitates visualization of intraarterial contrast injections using real-time MRI. Although designed for rapid deployment during rtMRI-guided interventional procedures, the technique may also be useful to supplement the study of vessel anatomy, flow, or perfusion.

13: Ilio-femoral CT Angiography with Ultra-Low Dose Intra-arterial Contrast Injection – A Novel Imaging Protocol to Assess Eligibility for Percutaneous Aortic Valve Replacement

13: Ilio-femoral CT Angiography with Ultra-Low Dose Intra-arterial Contrast Injection – A Novel Imaging Protocol to Assess Eligibility for Percutaneous Aortic Valve Replacement

Preoperative Visualization of the Artery of Adamkiewicz by Intra-Arterial CT Angiography

CT and MR angiographies have been reported to visualize the artery of Adamkiewicz (AKA) noninvasively to prevent spinal cord ischemia in surgery of thoracic descending aortic aneurysms. The purpose of this work was to compare the usefulness of CT angiography (CTA) with intra-arterial contrast injection (IACTA) with that of conventional CTA with intravenous contrast injection (IVCTA). We enrolled 32 consecutive patients with thoracic or thoracoabdominal aortic aneurysms who were scheduled for surgical repair or endovascular stent-graft treatment. All of the CTA images were obtained using a 16-detector row CT scanner and 100 mL of contrast material (370 mg/mL) injected at a rate of 5 mL/s. Contrast was injected via the antecubital veins of 15 patients and via a pig-tail catheter placed at the proximal portion of the descending aorta in 17 patients who underwent IVCTA and IACTA, respectively. Two datasets were reconstructed from 2 consecutive scans. The AKA was identified as a characteristic hairpin curved vessel in the anterior midsagittal surface of the spine and by the absence of further enhancement in the second rather than in the first phase. Continuity between the AKA and aorta was confirmed when the vessel could be traced continuously by paging the oblique coronal multiplanar reconstruction or original axial images. Intra-arterial contrast injection was significantly more sensitive in identifying the AKA than IVCTA: 16 (94.1%) of 17 versus 9 (60.0%) of 15 (P = .033). Continuity between the AKA and aorta through intercostal or lumbar artery was confirmed in 14 (87.5%) of 16 and 5 (55.6%) of 9 of the IACTA and IVCTA groups, respectively. Intra-arterial contrast injection detected the AKA at a high rate and verified continuity from the aorta to the AKA.

The Adamkiewicz artery: demonstration by intra-arterial computed tomographic angiography

The purpose of this study was to evaluate the feasibility of using multidetector-row CT angiography (CTA) with intra-arterial contrast injection (IA-CTA) to depict the artery of Adamkiewicz (arteria radicularis magna, ARM). We performed IA-CTA in 27 preoperative patients with aneurysm or dissection of the descending thoracic or thoracoabdominal aorta. ARM was examined on multiplanar and curved planar reformation images and on the paging method, and we investigated detectability and visualization of the ARM, the level of branching, and right/left frequency as well as continuity from the origin to the ARM. Furthermore, the bolus characteristic of contrast medium in IA-CTA was investigated and compared with CTA with intravenous contrast injection (IV-CTA). The bolus characteristic of the contrast medium was assessed by the determination of the CT value in the aorta in each of the 16 cases in which both IA-CTA before surgery and intravenous IV-CTA at the time of admission were performed. The ARMs were clearly visualized and at least one ARM to be reserved was determined in all patients (100%). The average number of ARM observed was 1.4+/-0.58 per patient (39/27). Innate origin was determined in 90% (35/39) of ARMs and it ranged between the 8th thoracic vertebra and the 3rd lumbar vertebra levels, and branching from the left accounted for 63.2% (24/38). It was possible to observe the exact continuity from the innate origin to the ARM as well as from the secondary origin to the ARM mediated by collateral vesseles in 61.5% of the total ARMs (24/39). The CT value in the aorta calculated on IA-CTA was significantly higher than that on IV-CTA (p<0.05). As a result, the high bolus characteristic of contrast medium in IA-CTA was confirmed. It was possible to detect the ARM in all patients and to obtain information about the origin by IA-CTA. This method is considered useful for preoperative assessment of a descending thoracic or a thoracoabdominal aorta for aortic aneurysm or dissection.

Comparison between intravenous and intraarterial contrast injections for dynamic 3D MRI of liver tumors in the VX2 rabbit model

To test the hypothesis that catheter-directed intraarterial (IA) contrast agent injection increases tumor enhancement and conspicuity compared to intravenous (IV) injection. Eight VX2 liver tumors were grown in five rabbits. After positioning a catheter in the hepatic artery, we performed 3D inversion recovery GRE MRI after IA and IV gadopentetate-dimeglumine contrast injections at doses of 0.04 and 0.1 mmol/kg, respectively. Peak enhancement (signal-to-noise ratio (SNR)) and conspicuity (contrast-to-noise ratio (CNR)) were measured for each acquisition. The peak SNR and CNR were 21.7 +/- 5.8 and 17.0 +/- 4.8 (mean +/- SD) after IA injection, and 16.9 +/- 10.2 and 6.2 +/- 2.6 after IV injection. The IA CNR was significantly greater than the IV CNR (P < 0.05), with a >60% increase in CNR for each tumor. For six of the eight tumors the IA SNR was greater than the IV SNR, but statistical significance was not achieved due to the small sample size of the study (P = 0.07). We demonstrated the feasibility of using IA injection techniques to improve tumor conspicuity. This strategy could be employed to enhance the detection of small liver tumors or to conserve contrast agent in future MRI-guided transcatheter liver therapies.

Balloon Test Occlusion with Perfusion CT Imaging Utilizing Intraarterial Contrast Injection

Balloon Test Occlusion (BTO) is performed to evaluate the collateral flow when a permanent therapeutic occlusion of unilateral carotid artery is planned. BTO with neurological evaluation alone, however, has a rather high false negative rate. In order to improve the sensitivity, several adjunctive procedures such as induced hypotension or cerebral blood flow (CBF) measurement with various modalities have been combined. Perfusion CT (PCT) is another imaging modality that is mainly used for the diagnosis of acute stroke. In this study, we evaluate the efficacy and the safety of BTO combined with PCT in the same procedure utilizing intraarterial contrast injection from the catheter. Seven patients underwent BTO with PCT in our institution. All the procedures were performed in the angio/CT combination suite. BTO was performed in the usual fashion and when the patient passed the 30 minutes' BTO clinically, PCT was performed subsequently. Contrast material was injected from a Pig Tail catheter placed in the ascending aorta. The obtained data were transferred to a workstation and perfusion maps of CBF, cerebral blood volume (CBV), and time to peak (TTP) were generated using software. In three patients, single photon emission CT (SPECT) was also obtained with administering 99 mTc-ethyl cysteinate dimer (99 mTc-ECD) intravenously during BTO. Although all the patients had passed the BTO clinically, the CBF maps of three patients revealed significant decrease in the occluded hemisphere. There was no procedure-related morbidity. PCT using intraarterial contrast injection during BTO was performed successfully and safely. Intraarterial injection allowed us to obtain excellent time-attenuation curves by utilizing less contrast material and less radiation doze.

Duplex–assisted internal carotid artery balloon angioplasty and stent placement: A novel approach to minimize or eliminate the use of contrast material

Carotid artery balloon angioplasty and stenting (CBAS) is emerging as an acceptable alternative to carotid endarterectomy in selected high-risk patients. Conversely, patients with pre-existing renal impairment, diabetes, or both may be harmed by the nephrotoxic contrast agents required during CBAS. We attempted to limit or eliminate the use of contrast material during CBAS. Eighteen patients with severe carotid stenoses (>70%) underwent CBAS at our institution over the last 12 months with duplex scan-assisted CBAS. Of these, 12 were primary procedures, and 6 were performed for carotid re-stenosis. Fourteen patients (78%) were neurologically asymptomatic. The average age of these patients was 75 +/- 11 years (range, 44-92 years). Hypertension, chronic renal insufficiency (serum creatinine level > or =1.5 mg/dL), coronary artery disease, diabetes, and smoking were present in 89%, 67%, 59%, 33%, and 28% of patients, respectively. Preoperative duplex carotid mapping was performed in all cases. All procedures were performed with patients under local anesthesia and light sedation. An ATL HDI 5000 scanner with the SonoCT feature was used. The common femoral artery was cannulated with a single-entry needle under direct ultrasound visualization. Fluoroscopy was used to assist passage of the guidewire into the aorta and the common carotid artery. In only four cases (22%) was an aortic arch angiogram obtained. Selective catheterization of the internal and external carotid arteries was performed under ultrasound guidance. The distal cerebral protection device (17 cases) was placed under fluoroscopic guidance. Balloon width and length were chosen according to ultrasound measurements. Balloon and stent deployment were successfully achieved with ultrasound guidance alone in all cases. Appropriate stent apposition and resolution of the stenosis was confirmed by duplex scanning in all cases. Five patients (28%) were noted to have low (<100 mL/min) internal carotid artery volume flow after stent deployment (range, 20-88 mL/min; mean +/- SD, 50 +/- 25 mL/min). The internal carotid artery volume flow increased immediately after Filterwire retrieval in all cases and ranged from 136 to 400 mL/min (mean, 245 +/- 107 mL/min). This increase was statistically significant ( P < .02). No ipsilateral strokes or deaths occurred during follow-up from 1 to 12 months (mean follow-up, 5 months). Duplex scan-assisted CBAS is feasible and may reduce the need for intra-arterial contrast injection in selected patients deemed at high risk for renal failure from nephrotoxic contrast material. Additional advantages include direct visualization of the puncture site, precise position of the balloon and stent, and B-mode and hemodynamic confirmation of the adequacy of the technique.

Imaging of Multistep Human Hepatocarcinogenesis by CT during Intra-Arterial Contrast Injection

Various types of hepatocellular nodules are seen in cirrhotic livers. In these nodules, two types of human hepatocarcinogenesis are now considered. One is de novo hepatocarcinogenesis and the other is the stepwise development from high-grade dysplastic nodule (DN), high-grade DN with well-differentiated HCC foci, and overt HCC. According to our analysis by CT during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) and histological study, in accordance with the elevation of the grade of malignancy of the nodules, the portal tract including normal portal vein (intranodular portal supply) and hepatic artery (intranodular arterial supply through normal hepatic arteries) are decreased. On the other hand, abnormal artery (intranodular arterial supply through newly formed abnormal arteries) gradually increases. Therefore, we can estimate the grade of malignacy of the nodules from intranodular blood supply. To know this blood supply pattern is important for the early detection, characterization and treatment of early stage HCCs. We also revealed that there was a close correlation between the prognosis of the nodules and the blood supply patterns.

Intra- and perinodular hemodynamics of hepatocellular carcinoma: CT observation during intra-arterial contrast injection.

It is imperative to understand the intraand perinodular hemodynamics of hepatocellular carcinoma (HCC) for precise imaging diagnosis and determination of treatment strategies. For this purpose, the combination of computed tomography (CT) and selective arteriography, such as CT during hepatic arteriography (CTHA) and CT during arterial portography (CTAP), is most valuable and precise. We introduced CTAP as a part of an arteriographic examination for preoperative evaluation of HCC in the 1980s [1], and, after the development of helical CT system, simultaneous performance of CTAP and CTHA became possible [2]. In this article, the intraand peritumoral hemodynamics analyzed by CTHA and CTAP are compared with histology.

Balloon Test Occlusion with Perfusion CT Imaging Utilizing Intraarterial Contrast Injection

Balloon Test Occlusion (BTO) is performed to evaluate the collateral flow when a permanent therapeutic occlusion of unilateral carotid artery is planned. BTO with neurological evaluation alone, however, has a rather high false negative rate. In order to improve the sensitivity, several adjunctive procedures such as induced hypotension or cerebral blood flow (CBF) measurement with various modalities have been combined. Perfusion CT (PCT) is another imaging modality that is mainly used for the diagnosis of acute stroke. In this study, we evaluate the efficacy and the safety of BTO combined with PCT in the same procedure utilizing intraarterial contrast injection from the catheter. Seven patients underwent BTO with PCT in our institution. All the procedures were performed in the angio/CT combination suite. BTO was performed in the usual fashion and when the patient passed the 30 minutes' BTO clinically, PCT was performed subsequently. Contrast material was injected from a Pig Tail catheter placed in the ascending aorta. The obtained data were transferred to a workstation and perfusion maps of CBF, cerebral blood volume (CBV), and time to peak (TTP) were generated using software. In three patients, single photon emission CT (SPECT) was also obtained with administering 99mTc-ethyl cysteinate dimer (99mTc-ECD) intravenously during BTO. Although all the patients had passed the BTO clinically, the CBF maps of three patients revealed significant decrease in the occluded hemisphere. There was no procedure-related morbidity. PCT using intraarterial contrast injection during BTO was performed successfully and safely. Intraarterial injection allowed us to obtain excellent time-attenuation curves by utilizing less contrast material and less radiation doze.

Absolute phasic blood flow measurement in the brain using digital subtraction angiography.

In this study, an angiographic method using first-pass distribution analysis was used for quantification of phasic volumetric blood flow. Studies were conducted in an angiographic perfusion phantom and in an animal model (rabbit) after intraarterial injection of contrast material. Digital subtraction angiography and first-pass distribution algorithm were used to assess the absolute volumetric flow rates. The method, based on the conservation of contrast material in successive angiographic images, uses the videodensitometric information in the arterial bed. Measurements were made by summing the pixel values in the region of interest, covering the whole perfusion bed. A contrast pass curve was generated for a sequence of images to obtain instantaneous volumetric flow rates. Instantaneous and mean absolute volumetric flow measurements made in the angiographic perfusion phantom and the common carotid artery of the animal models correlated well with validation measurements made using ultrasound flowprobes. The measured (M) and known (K) flow rates in the carotid artery were related by M = 0.87 K + 2.50 mL/minute (r = 0.96, standard error of the estimate = 3.79 mL/minute, n = 25) and M = 0.92 K - 1.00 mL/minute (r = 0.98, standard error of the estimate = 4.04 mL/minute, n = 38) using the videodensitometric and entrance vessel calibration techniques, respectively. Conclusion. Results demonstrate the potential use of the first-pass distribution method in conjunction with digital subtraction angiography for measuring phasic arterial blood flow in vivo.

Surgical Interruption of Patellar Blood Supply by Total Knee Arthroplasty

Arterial blood supply of the patella was demonstrated in 21 cadaver knees by intraarterial injection of radiopaque contrast. When the standard medial parapatellar approach or lateral retinacular release was carried out at a distance of at least 1 cm from the margin of the patella, some steps in total knee arthroplasty caused no impairment and others jeopardized the filling of intraosseous vessels. The radial intraosseous vessels are jeopardized by osteotomy of a deformed patella or excision of fat pad. The prepatellar vessels greatly contribute to intraosseous vascularization and should be carefully preserved.

Digital subtraction angiography of the aorta

The results of 300 digital subtraction angiographies of the thoracic and abdominal aorta are analysed. Following intraarterial injection of contrast, all examinations were of good quality. Following I-V DSA, two thoracic (1.8%) and two abdominal (1.2%) aortograms were non-diagnostic. Anomalies in the position of the aorta, dilatation (aneurysm) or stenoses (coarctations, arteriosclerosis, occlusions) could be diagnosed by I-V DSA. One I-A DSA was performed for aneurysm of the ascending aorta in order to evaluate function of the aortic valve and for demonstrating the coronary artery origins, and pre-operatively for an aortic dissection.

Digital subtraction angiography: current clinical applications.

The applications of digital subtraction angiography (DSA) in neurologic diagnosis have been evolving as clinical experience with this technology accumulates. Initial enthusiasm with the intravenous contrast material injections has been tempered by often equivocal results. Intravenous DSA (IV-DSA) is still an accurate screening technique for extracranial carotid atherosclerosis, comparable to duplex ultrasound. Intracranial imaging is less satisfying with intravenous injections but reliable information is available in the assessment of the venous sinuses and parasellar internal arteries. The future of DSA lies with intraarterial contrast injections, as this technique substantially decreases the risks and costs of definitive cerebrovascular investigation.