scholarly journals Two-Volume Dynamic CT Pulmonary Perfusion: Contrast Timing Optimization

2021 ◽  
Author(s):  
Yixiao Zhao ◽  
Logan Hubbard ◽  
Shant Malkasian ◽  
Pablo Abbona ◽  
Sabee Molloi
Keyword(s):  
Radiation Dose ◽  
Ct Perfusion ◽  
Optimal Timing ◽  
Pulmonary Perfusion ◽  
Dynamic Ct ◽  
Perfusion Technique ◽  
Low Radiation Dose ◽  
Time To Peak ◽  
Injection Duration ◽  
Perfusion Measurements

Abstract PurposeTo develop and validate an optimal timing protocol for a low-radiation-dose CT pulmonary perfusion technique using only two volume scans.MethodsA total of 24 swine (48.5 ± 14.3 kg) underwent contrast-enhanced dynamic CT. Multiple contrast injections were made under different pulmonary perfusion conditions, resulting in a total of 147 complete pulmonary arterial input functions(AIF). Using the AIFs, an optimal timing protocol for acquisition of two-volume scans was developed for the first-pass CT perfusion technique. Specifically, the first volume scan was obtained at the base of the AIF using bolus-tracking and the second volume scan was obtained at the peak of the AIF using a time-to-peak relation derived by regression analysis. Additionally, a subset of 14 swine with 60 CT acquisitions were used to validate the prospective timing protocol. The prospective perfusion measurements using the two-volume scans, were quantitatively compared to the retrospective perfusion measurements using the entire AIF with t-test, linear regression and Bland-Altman analysis. The CT dose index(CTDI32vol) and size-specific dose estimate(SSDE) of the two-volume perfusion technique were also determined.ResultsThe pulmonary artery time-to-peak (TPA) was related to one-half of the contrast injection duration(TInj/2) by TPA = 1.06 TInj/2+0.090 (r=0.97). Simulated prospective two-volume perfusion measurements (P­­PRO) in ml/min/g were related to the retrospective measurements (PRETRO) by PPRO= 0.87PRETRO + 0.56 (r=0.88). The CTDI32vol and SSDE of the two-volume CT technique were estimated to be 28.4 and 47.0mGy, respectively.ConclusionThe optimal timing protocol can enable an accurate, low-radiation-dose two-volume dynamic CT perfusion technique.

scholarly journals Two-volume Dynamic CT Pulmonary Perfusion: Contrast Timing Optimization 

2021 ◽  
Author(s):  
Yixiao Zhao ◽  
Logan Hubbard ◽  
Shant Malkasian ◽  
Pablo Abbona ◽  
Sabee Molloi
Keyword(s):  
Radiation Dose ◽  
Ct Perfusion ◽  
Optimal Timing ◽  
Pulmonary Perfusion ◽  
Dynamic Ct ◽  
Perfusion Technique ◽  
Low Radiation Dose ◽  
Time To Peak ◽  
Injection Duration ◽  
Perfusion Measurements

Abstract Purpose: To develop and validate an optimal timing protocol for a low-radiation-dose CT pulmonary perfusion technique using only two volume scans.Methods: A total of 24 swine (48.5±14.3 kg) underwent contrast-enhanced dynamic CT. Multiple contrast injections were made under different pulmonary perfusion conditions, resulting in a total of 147 complete pulmonary arterial input functions(AIFs). Using all the AIF curves, an optimal contrast timing protocol was developed for a first-pass, two-volume dynamic CT perfusion technique (one at the base and the other at the peak of AIF curve). A subset of 14 swine with 70 CT acquisitions were used to validate the prospective timing protocol. The prospective two-volume perfusion measurements were quantitatively compared to the previously validated retrospective perfusion measurements with t-test, linear regression and Bland-Altman analysis. Results: The pulmonary artery time-to-peak ( Tpa) was related to one-half of the contrast injection duration( Tinj/2) by Tpa = 1.06 Tinj/2 + 0.90 (r=0.97). The prospective two-volume perfusion measurements (P­­PRO) were related to the retrospective measurements (PRETRO) by PPRO=0.87PRETRO+0.56 (r=0.88). The CT dose index and size-specific dose estimate of the two-volume CT technique were estimated to be 28.4 and 47.0mGy, respectively. Conclusion: The optimal timing protocol can enable an accurate, low-radiation-dose two-volume dynamic CT perfusion technique.

scholarly journals Dynamic CT perfusion for acute cerebral ischemia: increasing anatomical coverage with the “toggling table” technique

Stroke ◽  
2001 ◽  
Vol 32 (suppl_1) ◽  
pp. 342-342
Author(s):  
Heidi C Roberts ◽  
William P Dillon ◽  
Jack W Tsao ◽  
Nancy J Fischbein ◽  
Wade S Smith
Keyword(s):  
Acute Stroke ◽  
Ct Perfusion ◽  
Mean Transit Time ◽  
Perfusion Ct ◽  
Dynamic Ct ◽  
Tissue Ischemia ◽  
Time To Peak ◽  
Acute Cerebral Ischemia ◽  
Perfusion Scan ◽  
Perfusion Assessment

P17 Computed tomography (CT) has experienced a revival for perfusion assessment in acute stroke. However, so far it is limited by its small anatomical coverage. We studied a toggling table approach to (multislice) dynamic perfusion CT for extended coverage in patients with suspected acute MCA ischemia. In 20 patients with suspected acute MCA ischemia, a dynamic CT perfusion scan was performed on a multidetector scanner. To increase anatomical coverage, 2 distinct “toggling” table positions (each consisting of two 1cm slices) were chosen to represent the MCA territory and scanned in an alternating fashion during the bolus injection of 40mL contrast agent. Dynamic images were evaluated on a ROI and pixel-by-pixel basis, estimating peak density change, time to peak (TTP), integral (rCBV), mean transit time (MTT), and flow (rCBF). Acutely acquired CT perfusion data were compared with follow-up CT or MR (perfusion and diffusion) images. With the toggling table approach, temporal resolution is reduced to approximately 5 secs. Four imaging slices at two distinct locations can be obtained, covering the MCA territory. In 15 patients, perfusion CT revealed focal abnormalities in at least one slice, most commonly on MTT maps. In 14 of these 15 patients, the area of perfusion abnormality was a good predictor of the ultimate infarct. A single table location approach would have underestimated or missed the involved tissue in most cases. In 5 of the 20 patients, perfusion maps failed to delineate any abnormality: in 4 cases, MRI confirmed the absence of ischemia, in 1 case, CT failed to reveal a small ischemic injury visible on diffusion MRI. Addition of the dynamic CT perfusion scan adds less than 5 minutes to a CT stroke protocol and can be coupled with CTA studies to image the cervical and cerebral vasculature in acute stroke. The dynamic CT perfusion technique is a practical and useful tool for the emergency assessment of acute stroke patients. By employing the toggling table approach, perfusion information can be obtained over an extended anatomic area and thus reveal the presence and the extent of presumed tissue ischemia.

Molecular Breast Imaging at Ultra-Low Radiation Dose

2020 ◽  
Vol 215 (2) ◽  
pp. W30-W30
Author(s):  
Matthew F. Covington ◽  
Matthew Brown
Keyword(s):  
Radiation Dose ◽  
Breast Imaging ◽  
Low Radiation Dose ◽  
Molecular Breast Imaging

scholarly journals Dynamic Quantitative Iodine Myocardial Perfusion Imaging with Dual-Layer CT using a Porcine Model

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Kai Scherer ◽  
Johannes Hammel ◽  
Thorsten Sellerer ◽  
Korbinian Mechlem ◽  
Bernhard Renger ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Perfusion Imaging ◽  
Porcine Model ◽  
Ct Perfusion ◽  
Dual Energy Ct ◽  
Beam Hardening ◽  
Low Contrast ◽  
Time To Peak ◽  
Coronary Ct

Abstract Ischemic heart disease is the globally leading cause of death. When using coronary CT angiography, the functional hemodynamics within the myocardium remain uncertain. In this study myocardial CT perfusion imaging using iodine contrast agent demonstrated to strongly improve the assessment of myocardial disorders. However, a retrieval of such dynamics using Hounsfield units from conventional CT poses concerns with respect to beam-hardening effects and low contrast-to-noise ratio (CNR). Dual-energy CT offers novel approaches to overcome aforementioned limitations. Quantitative peak enhancement, perfusion, time to peak and iodine volume measurements inside the myocardium were determined resulting in 0.92 mg/ml, 0.085 mg/ml/s 17.12 s and 29.89 mg/ml*s, respectively. We report on the first extensive quantitative and iodine-based analysis of myocardial dynamics in a healthy porcine model using a dual-layer spectral CT. We further elucidate on the potential of reducing the radiation dose from 135 to 18 mGy and the contrast agent volume from 60 to 30 mL by presenting a two-shot acquisition approach and measuring iodine concentrations in the myocardium in-vivo down to 1 mg/ml, respectively. We believe that dynamic quantitative iodine perfusion imaging may be a highly sensitive tool for the precise functional assessment and monitoring of early myocardial ischemia.

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