Injection of contrast media using a large-bore angiography catheter with a guidewire in place: Physical factors influencing injection pressure in cerebral angiography

Background We have used a contrast injection scheme termed as “guided catheterization method (guided method).” By using a large-bore 5-Fr catheter and 0.032-in guidewire, a contrast medium could be injected without removing the guidewire. Using a neurovascular phantom, we studied the influence of leaving the guidewire on the contrast injection pressure. Image quality was compared with that obtained using a 4-Fr regular angiography catheter (conventional method). Methods Actual contrast injection pressure, flow rate, flow volume, and several variables from the time-density curve (TDC) were obtained using the guided method and the conventional method. Catheterization parameters included flow rate, the viscosity of a contrast medium (CM), and catheter length. The pressure limit of a contrast injector was set as 1200 psi. Digital subtraction angiography (DSA) images on the neurovascular phantom were acquired. The DSA images were processed, and TDC on a specific region of interest was obtained. Variables from TDC were calculated and compared between the different catheters. Results The ranges of actual contrast injection pressure with the conventional and the guided method were 138–299 psi and 184–451 psi, respectively. A minimal reduction of the actual flow rate was found under some conditions with the guided method. Comparable opacifications in DSA images were achieved in all conditions. Although peak intensity was different by flow rate or CM, all TDC variables did not differ based on the catheter. There were no significant harmful events during the 90 experiments. Conclusions With adjustment of the pressure limit, cerebral angiography using the 5-Fr, large-bore catheter without removal of the guidewire is feasible, safe, and expected to provide image quality comparable to that of the 4-Fr regular catheter.

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A Systematic Review of Double Low-dose CT Pulmonary Angiography in Pulmonary Embolism

Current Medical Imaging Formerly Current Medical Imaging Reviews ◽

10.2174/1573405614666180813120619 ◽

2019 ◽

Vol 15 (5) ◽

pp. 453-460 ◽

Cited By ~ 1

Author(s):

Sultan Aldosari ◽

Zhonghua Sun

Keyword(s):

Systematic Review ◽

Pulmonary Embolism ◽

Image Quality ◽

Radiation Dose ◽

Contrast Medium ◽

Low Dose ◽

Pulmonary Angiography ◽

Ct Pulmonary Angiography ◽

Low Contrast ◽

Low Contrast Medium

Background: The aim of this study is to perform a systematic review of the feasibility and clinical application of double low-dose CT pulmonary angiography (CTPA) in the diagnosis of patients with suspected pulmonary embolism. Discussion: A total of 13 studies were found to meet selection criteria reporting both low radiation dose (70 or 80 kVp versus 100 or 120 kVp) and low contrast medium dose CTPA protocols. Lowdose CTPA resulted in radiation dose reduction from 29.6% to 87.5% in 12 studies (range: 0.4 to 23.5 mSv), while in one study, radiation dose was increased in the dual-energy CT group when compared to the standard 120 kVp group. CTPA with use of low contrast medium volume (range: 20 to 75 ml) was compared to standard CTPA (range: 50 to 101 ml) in 12 studies with reduction between 25 and 67%, while in the remaining study, low iodine concentration was used with 23% dose reduction achieved. Quantitative assessment of image quality (in terms of signal-to-noise ratio and contrast-to-noise ratio) showed that low-dose CTPA was associated with higher, lower and no change in image quality in 3, 3 and 6 studies, respectively when compared to the standard CTPA protocol. The subjective assessment indicated similar image quality in 11 studies between low-dose and standard CTPA groups, and improved image quality in 1 study with low-dose CTPA. Conclusion: This review shows that double low-dose CTPA is feasible in the diagnosis of pulmonary embolism with significant reductions in both radiation and contrast medium doses, without compromising diagnostic image quality.

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A technical note on intra-arterial cone-beam computed tomography for the evaluation of flow-diverter stents: Image quality differences between diluted and non-diluted contrast medium

Interventional Neuroradiology ◽

10.1177/1591019919890929 ◽

2019 ◽

Vol 26 (2) ◽

pp. 164-169

Author(s):

Naci Kocer ◽

Sedat G Kandemirli ◽

Daniel Ruijters ◽

Michalis Mantatzis ◽

Osman Kizilkilic ◽

...

Keyword(s):

Computed Tomography ◽

Image Quality ◽

Contrast Medium ◽

Cone Beam Computed Tomography ◽

Vessel Wall ◽

Flow Diverter ◽

Cone Beam ◽

Gray Scale ◽

Stent Deployment ◽

Contrast Technique

Background Design of flow-diverter stents for flexibility, tractability, and low profile limits their radiopacity on conventional digital subtraction angiography. Cone-beam computed tomography (CBCT) offers higher spatial resolution for the evaluation of flow-diverter stents. However, CBCT requires optimal dilution and timing of contrast medium for simultaneous visualization of the stent, arterial lumen, and vessel wall. There are only limited data on the effects of different contrast dilutions on CBCT image quality in neurointerventional applications. Materials and methods In our institution, intra-arterial CBCTs were acquired during stent deployment and at follow-ups with 10% diluted contrast. We had recently started acquiring intra-arterial CBCTs with non-diluted contrast. Retrospective analysis of our flow-diverter data identified eight cases with different aneurysm locations who had intra-arterial CBCT with 10% diluted contrast immediately after flow-diverter stent deployment and with non-diluted contrast technique during follow-ups. For each case, the image quality between diluted and non-diluted contrast techniques was compared qualitatively by assessing stent visualization and quantitatively by plotting gray-scale intensity values along the vessel lumen. Results In two sets of CBCT images per each case, there was no substantial difference between diluted and non-diluted CBTC techniques for the evaluation of stent architecture and lumen opacification. Gray-scale intensity values perpendicular to the lumen revealed similar intensity values along the neighboring parenchyma, vessel wall, and lumen for the two different contrast techniques. Conclusion Intra-arterial CBCT angiography can be performed without contrast dilution and still achieve adequate image quality in certain cerebral aneurysms treated with flow diverter. The non-diluted contrast technique avoids the time loss during preparation of diluted contrast and installation of diluted contrast to the injector in angiography suites with a single power injector.

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Renografin as a New Contrast Medium for Cerebral Angiography

Radiology ◽

10.1148/69.3.398 ◽

1957 ◽

Vol 69 (3) ◽

pp. 398-401 ◽

Cited By ~ 1

Author(s):

David J. LaFia ◽

Rudolph Jaeger

Keyword(s):

Contrast Medium ◽

Cerebral Angiography

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(2) Evaluation of image quality for physical factors

Japanese Journal of Radiological Technology ◽

10.6009/jjrt.kj00003533507 ◽

1992 ◽

Vol 48 (3) ◽

pp. 462

Keyword(s):

Image Quality ◽

Physical Factors

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Unloading Frac Hits in Gas Wells: How Does the Nitrogen Injection Rate and Pressure Affect the Unloading Process?

10.2118/200962-ms ◽

2021 ◽

Author(s):

Miguel Angel Cedeno

Keyword(s):

Multiphase Flow ◽

Flow Rate ◽

Injection Pressure ◽

Injection Rate ◽

Gas Wells ◽

Eagle Ford Shale ◽

Eagle Ford ◽

Nitrogen Injection ◽

Injection Flow ◽

Transient Multiphase Flow

Abstract The unconventional resources development has grown tremendously as a result of the advancement in horizontal drilling technology coupled with hydraulic fracturing. However, as more wells are drilled and fractured close to each other, frac hits have become a major challenge in these wells. The aim of this work is to investigate the effect of nitrogen injection flow rate and pressure on unloading frac hits gas wells in transient multiphase flow. A numerical simulation model was created using a transient multiphase flow simulator to mimic the unloading process of frac hits by injecting nitrogen from the surface through the annulus section of the well. Many simulation cases were created and analyzed to comprehend the effect of the nitrogen injection rate and pressure on the unloading of frac hits. The model mimicked real field data from currently active well in the Eagle Ford Shale. The results showed that as the nitrogen injection pressure increases, the nitrogen volume and the time to unload the frac hits decrease. On the other hand, increasing the injection rate of nitrogen will increase the nitrogen volume required to unload the frac hits. In addition, the time to unload frac hits will be decreased as the nitrogen injection rate increases. These results indicate that the time required to unload frac hits will be minimized if higher flow rates of nitrogen were utilized. Nonetheless, the volume of nitrogen required to unload the frac hits will be maximized. An important observation to highlight is that the operators can save money by reducing the time for injecting nitrogen. This observation was verified when increasing the injection pressure in the frac hit well in the Eagle Ford Shale, the time of injection was reduced 20%. This study presents the effects of nitrogen injection flow rate and injection pressure for unloading frac hits in gas wells. Due to the lack of published studies about this topic, this work can serve as a practical guideline for unloading frac hits in gas wells.

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Prognosis of Severe Head Injuries in Relation to the Flow Speed of Contrast Medium in Cerebral Angiography

Advances in Neurosurgery - Head Injuries. Tumors of the Cerebellar Region ◽

10.1007/978-3-642-67028-2_1 ◽

1978 ◽

pp. 1-4

Author(s):

H. Vogelsang ◽

C. Rieck

Keyword(s):

Contrast Medium ◽

Cerebral Angiography ◽

Head Injuries ◽

Flow Speed

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Relationship between CNR and visibility of anatomical structures of cone-beam computed tomography images under different exposure parameters

Dentomaxillofacial Radiology ◽

10.1259/dmfr.20190336 ◽

2020 ◽

Vol 49 (5) ◽

pp. 20190336

Author(s):

Miss Fei Wang ◽

Xiaoyan Xie ◽

Gang Li ◽

Zuyan Zhang

Keyword(s):

Image Quality ◽

Change Point ◽

Cone Beam Ct ◽

Cone Beam ◽

Physical Factors ◽

Anatomical Structures ◽

Subjective Image Quality ◽

Computed Tomography Images ◽

Tissue Equivalent ◽

Imagej Software

Objectives: The purpose of this study was to investigate the image quality of cone beam CT (CBCT) under different exposure parameters and the relationship between contrast-to-noise and visibility of eight anatomical structures. Methods: CBCT images for the evaluation of subjective image quality were acquired on an anthropopathic phantom containing a human skeleton embedded in soft tissue equivalent materials using 25 exposure protocols. Visibility of eight anatomical structures was evaluated by five independent observers. Using the SEDENTEXCT IQ Image Quality phantom, the contrast-to-noise ratio (CNR) was calculated by ImageJ software. Results: A reduction on the visibility of anatomical structures was seen under lower exposure parameters. However, for 84% of the protocols, visibility of anatomical structures remained acceptable even under some lower parameter settings. As CNR increased, the visibility of anatomical structures also increased correspondingly. A change point could be found in the CNR interval 29.42–36.51 after which the visibility of anatomical structures no longer increases with the increase of CNR. Conclusions: Although CNR decrease under a lower exposure parameter, the image quality often remained acceptable at exposure levels below the manufacture’s recommended settings. It is possible to standardize subjective image quality by physical factors. Currently, it is not possible to predetermine a change point CNR value due to different CBCT machine and variation of diagnostic tasks.

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Coronary CT angiography by modifying tube voltage and contrast medium concentration: Evaluation of image quality and radiation dose

Echocardiography ◽

10.1111/echo.14410 ◽

2019 ◽

Vol 36 (7) ◽

pp. 1391-1396 ◽

Cited By ~ 1

Author(s):

Seyede Shokoofeh Mousavi Gazafroudi ◽

Mohammad Bagher Tavakkoli ◽

Maryam Moradi ◽

Seyede Shabnam Mousavi Gazafroudi ◽

Ghasem Yadegarfar ◽

...

Keyword(s):

Image Quality ◽

Radiation Dose ◽

Contrast Medium ◽

Ct Angiography ◽

Coronary Ct Angiography ◽

Tube Voltage ◽

Medium Concentration ◽

Coronary Ct ◽

Contrast Medium Concentration

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High Pressure Injection of Chemicals in a Gravel Beach

Processes ◽

10.3390/pr7080525 ◽

2019 ◽

Vol 7 (8) ◽

pp. 525

Author(s):

Geng ◽

Abdollahi-Nasab ◽

An ◽

Chen ◽

Lee ◽

...

Keyword(s):

High Pressure ◽

Flow Rate ◽

Lithium Bromide ◽

Injection Pressure ◽

Tidal Range ◽

Application Of Surfactants ◽

Pressure Injection ◽

Oil Biodegradation ◽

High Pressure Injection ◽

Gravel Beach

The remediation of beaches contaminated with oil includes the application of surfactants and/or the application of amendments to enhance oil biodegradation (i.e., bioremediation). This study focused on evaluating the practicability of the high pressure injection (HPI) of dissolved chemicals into the subsurface of a lentic Alaskan beach subjected to a 5 m tidal range. A conservative tracer, lithium, in a lithium bromide (LiBr) solution, was injected into the beach at 1.0 m depth near the mid-tide line. The flow rate was varied between 1.0 and 1.5 L/min, and the resulting injection pressure varied between 3 m and 6 m of water. The concentration of the injected tracer was measured from four surrounding monitoring wells at multiple depths. The HPI associated with a flow rate of 1.5 L/min resulted in a Darcy flux in the cross-shore direction at 1.15 × 10−5 m/s compared to that of 7.5 × 10−6 m/s under normal conditions. The HPI, thus, enhanced the hydraulic conveyance of the beach. The results revealed that the tracer plume dispersed an area of ~12 m2 within 24 h. These results suggest that deep injection of solutions into a gravel beach is a viable approach for remediating beaches.

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