Technical prerequisites and imaging protocols for CT perfusion imaging in oncology

Klotz, Ernst; Haberland, Ulrike; Glatting, Gerhard; Schoenberg, Stefan O.; Fink, Christian; Attenberger, Ulrike; Henzler, Thomas

doi:10.1016/j.ejrad.2015.06.010

Cited by 32 publications

(29 citation statements)

References 44 publications

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“…Based on a recently published review recommending how to optimize CT-perfusion protocols in the light of current knowledge about strengths and limitations of the available mathematical calculation models and suggesting ways to standardize the state of the art examinational protocols, the aim of the study was to make a comparison of results obtained with the recommended perfusion protocol and available calculation methods and report about the magnitude of obtained perfusion values as well as of their ranges and correlations with the histologic differentiation grade [18]. …”

Section: Resultsmentioning

confidence: 99%

“…On the contrary, Tan et al obtained considerably higher BF values 60 ± 15.3 ml/min/100 g using lower temporal resolution during the first pass phase [22]. In particular, in the maximum slope model, temporal resolution between the start of contrast agent administration and the peak enhancement should be kept as high as technical feasible in order to avoid false high miscalculation [18]. Accordingly, the report by Li et al using a reduced-dose examinational CT-perfusion protocol comparable to ours yielded similar results for BF, BV as well as for k-trans using the Patlak calculation model [23].…”

Section: Resultsmentioning

confidence: 99%

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CT-perfusion measurements in pancreatic carcinoma with different kinetic models: Is there a chance for tumour grading based on functional parameters?

et al. 2016

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BackgroundTo evaluate the interchangeability of perfusion parameters obtained with help of models used for post-processing of perfusion-CT images in pancreatic adenocarcinoma and to determine the mean values and ranges of perfusion in different tumour gradings.MethodsPerfusion-CT imaging was performed prospectively in 48 consecutive patients with pancreatic adenocarcinoma. In 42 patients biopsy-proven tumor grading was available (4 × G1/24 × G2/14 × G3/6× unknown). Images were post-processed using a model based on the maximum-slope (MS) approach (blood flow-BFMS) + Patlak analysis (P) (blood volume [BVP] and permeability [k-transP]), as well as a model with deconvolution-based (D) analysis (BFD, BVD and k-transD). 50 mL contrast agent were applied with a delay time of 7 s. Perfusion parameters were compared using intraclass correlation coefficient (ICC), the Wilcoxon matched-pairs test and Bland-Altman plots.ResultsForty eight VOIs of tumours were outlined and analysed. Moderate to good ICC values were found for the perfusion parameters (ICC = 0.62–0.75). Wilcoxon matched-pairs revealed significantly lower values (P < .001 and 0.008), for the BF and BV values obtained using the maximum-slope approach + Patlak analysis compared to deconvolution based analysis. For k-trans measurement, deconvolution revealed significantly lower values (P < 0.001). Different histologic subgroups (G1-G3) did not show significantly different functional parameters.ConclusionThere were significant differences in the perfusion parameters obtained using the different calculation methods, and therefore these parameters are not directly interchangeable. However, the magnitude of pairs of parametric values is in constant relation to each other enabling the use of any of these methods. VPCT parameters did not allow for histologic classification.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

CT-perfusion measurements in pancreatic carcinoma with different kinetic models: Is there a chance for tumour grading based on functional parameters?

et al. 2016

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“…Similar enhancement of the arteries of the pulmonary and systemic circulation could be achieved with 50% of CM volume and 50% injection speed with 70 kV as compared to a 120 kV CTA. For dynamic or perfusion CT (PCT), very rapid injection of relatively small CM volumes and scanning at low kV has been recommended [12, 15–17]. The short and compact CM bolus is required to satisfy the assumptions of the perfusion models.…”

Section: Discussionmentioning

confidence: 99%

“…When the scan time of a body CTA is on the order of 5 s or less, the traditional CM injection protocols need to be reconsidered and short and compact injection protocols should be preferred to those protocols that are optimized to provide a long and stable plateau phase of enhancement [10]. High peak enhancement with low CM volume can be achieved with monophasic injection protocols and a high iodine delivery rate (IDR) [11, 12], and it has been demonstrated, that even very high flow rates can safely injected with special i.v. lines [13].…”

Section: Introductionmentioning

confidence: 99%

Relationship between low tube voltage (70 kV) and the iodine delivery rate (IDR) in CT angiography: An experimental in-vivo study

et al. 2017

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ObjectiveVery short acquisition times and the use of low-kV protocols in CTA demand modifications in the contrast media (CM) injection regimen. The aim of this study was to optimize the use of CM delivery parameters in thoraco-abdominal CTA in a porcine model.Materials and methodsSix pigs (55–68 kg) were examined with a dynamic CTA protocol (454 mm scan length, 2.5 s temporal resolution, 70 s total acquisition time). Four CM injection protocols were applied in a randomized order. 120 kV CTA protocol: (A) 300 mg iodine/kg bodyweight (bw), IDR = 1.5 g/s (flow = 5 mL/s), injection time (ti) 12 s (60 kg bw). 70 kV CTA protocols: 150 mg iodine/kg bw: (B) IDR = 0.75 g/s (flow = 2.5 mL/s), ti = 12 s (60 kg bw); (C) IDR = 1.5 g/s (flow = 5 mL/s), ti = 12 s (60 kg bw); (D) IDR = 3.0 g/s (flow = 10 mL/s), ti = 3 s (60 kg bw). The complete CM bolus shape was monitored by creating time attenuation curves (TAC) in different vascular territories. Based on the TAC, the time to peak (TTP) and the peak enhancement were determined. The diagnostic window (relative enhancement > 300 HU), was calculated and compared to visual inspection of the corresponding CTA data sets.ResultsThe average relative arterial peak enhancements after baseline correction were 358.6 HU (A), 356.6 HU (B), 464.0 HU (C), and 477.6 HU (D). The TTP decreased with increasing IDR and decreasing ti, protocols A and B did not differ significantly (systemic arteries, p = 0.843; pulmonary arteries, p = 0.183). The delay time for bolus tracking (trigger level 100 HU; target enhancement 300 HU) for single-phase CTA was comparable for protocol A and B (3.9, 4.3 s) and C and D (2.4, 2.0 s). The scan window time frame was comparable for the different protocols by visual inspection of the different CTA data sets and by analyzing the TAC.ConclusionsAll protocols provided sufficient arterial enhancement. The use of a 70 kV CTA protocol is recommended because of a 50% reduction of total CM volume and a 50% reduced flow rate while maintaining the bolus profile. In contrast to pulmonary arterial enhancement, the systemic arterial enhancement improved only slightly increasing the IDR from 1.5 g/s to 3 g/s because of bolus dispersion of the very short bolus (3s) in the lungs.

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“…The major obstacle to CTP wide employment in clinical routine resides in the unavoidably higher dose compared to nondynamic conventional CT scans . Dose can be partially reduced in the first place by optimizing acquisition parameters like kV, mAs, sampling time, coverage, and number of acquired time points, but there are serious intrinsic limitations to dose reduction in CTP . In fact, perfusion models are very sensitive to noise as they always involve some sort of derivative or deconvolution equivalent process .…”

Section: Introductionmentioning

confidence: 99%

Noise reduction and functional maps image quality improvement in dynamic CT perfusion using a new k-means clustering guided bilateral filter (KMGB)

et al. 2017

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In conclusion, the KMGB filter leads to superior results for CT images and functional maps quality improvement, in significantly shorter computational times compared to the other filters. Our results suggest that the KMGB filter might be a more robust solution for halved-dose CTP datasets. For all the filters investigated, some artifacts start to appear on the BF maps if one sixth of the dose is simulated, suggesting that no one of the filters investigated in this study might be optimal for such a drastic dose reduction scenario.

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Technical prerequisites and imaging protocols for CT perfusion imaging in oncology

Cited by 32 publications

References 44 publications

CT-perfusion measurements in pancreatic carcinoma with different kinetic models: Is there a chance for tumour grading based on functional parameters?

CT-perfusion measurements in pancreatic carcinoma with different kinetic models: Is there a chance for tumour grading based on functional parameters?

Relationship between low tube voltage (70 kV) and the iodine delivery rate (IDR) in CT angiography: An experimental in-vivo study

Noise reduction and functional maps image quality improvement in dynamic CT perfusion using a new k-means clustering guided bilateral filter (KMGB)

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