Schönfeld, et al. (2023) [33]

Retrospective study

n = 81

High-pitch CTPA, 20 ml ICM (n = 41)

Standard CTPA, 50 ml ICM (n = 40)

Good to excellent subjective image quality in over 90% of all exams with no significant difference between the groups.

Significantly lower mean contrast opacification, noise values and CNR in all segmented PA in test group compared to control group but within acceptable diagnostic limits.

Saeed, et al. (2023) [34]

Retrospective study

n = 105

High-pitch PCD-CTPA, 35 ml (n = 29), 45 ml (n = 62), 60 ml (n = 14) ICM

Comparison of image quality between the 3 groups

Ratings: 4.6/5 (group 1), 4.5/5 (group 2), 4.1/5 (group 3). Significant difference between groups 1 and 3and between groups 2 and 3.

No significant difference in CNR, mean attenuation (HU), mean density (HU) in all evaluated PA locations in all groups.

Pannenbecker,et al. (2023) [37]

Retrospective study

n = 64

PCD-CTPA, 25 ml ICM (n = 32)

DE-CTPA, 50 ml ICM (n = 32)

Superior subjective image quality for 60-keV PCD scans (excellent or good ratings in 93.8% of PCD vs. 84.4% of 60 keV DE scans).

Significantly higher objective image quality parameters in the control group, both in the polychromatic reconstructions and at 60 keV.

Çeltikçi, et al. (2022) [49]

Retrospective study

n = 91

DE-CTPA, 40 ml ICM (n = 42)

Standard CTPA, 60ml ICM (n = 49)

No significant difference between the test and control group in a five-point scale scores for PA CE and image noise.

No significant difference between the test and control group in attenuation values (HU) in five PA locations, mean attenuation value (HU), mean background noise, SNR and CNR.

Wu, et al. (2020) [50]

Prospective observational study

n = 70

Biphasic time-enhancement curves approach, 80 kVp, 10 ml ICM (n = 35)

Test-bolus approach, 100 kVp, 20 ml ICM (n = 35)

Better PA image quality in the test group compared to the control group, with artifact reduction in the superior vena cava and subclavian vein.

Lower CT values, SNR and CNR of the evaluated PA and PV in the test group compared to the control group.

Silva, et al. (2020) [51]

Retrospective study

n = 176

CTPA with 20 ml ICM (n = 102)

CTPA with 40 ml ICM (n = 74)

Significant lower semi-qualitative scores for central and peripheral PACE for the test group. Comparable semi-qualitative image noise between the two groups.

Lower mean CE for the test group, though higher than the diagnostic threshold of 250 HU in both groups. Lower SNR and CNR for the test group compared to the control group.

Kamr, et al. (2020) [52]

Prospective study

n = 600

Test-bolus CTPA technique, 50 ml ICM (n = 300)

Bolus-tracking CTPA technique, 80-100 ml ICM (n = 300)

35% average diagnostic quality score increase from 1.75 in control group to 2.8 in test group.

Main PA average density increase from 260.5 HU in control group to 320 HU in test group. Ascending aorta average density decrease from 250 HU in control group to 130 HU in test group B.

Meyer, et al. (2018) [53]

Prospective study

n = 150

Optimized DE-CTPA, 45 ml mixture of ICM and saline [5.4 gr iodine load] (n = 50)

Standard CTPA or standard DE-CTPA, 80 ml ICM [32 gr iodine load] (n = 100)

No significant difference in the median image quality or the median image noise for:- Both the 40 keV and 50 keV VMS data set between both DE-CTPA protocol VMS datasets for the main and peripheral PA.

-both DE-CTPA 40 keV and 50 keV protocols compared to the standard CTPA protocol.

Highest CNR of main PA at 50 keV and peripheral PA at 40 keV for both standard and optimized DE-CTPA. Significantly higher CNR values for the standard DE-CTPA.

Suntharalingam, et al. (2017) [54]

Retrospective study

n = 100

80 kVp CTPA, 25 ml ICM on a dual-source CT (n = 50)

100 kVp CTPA, 60 ml ICM on a dual-source CT (n = 50)

No significant difference in subjective image quality scores of PA between the two groups.

Objective image analysis revealed that signal intensities (SI), SNR and CNR of the PA were equal or significantly higher in the control group.

Chen, et al. (2017) [55]

Retrospective observational study

n = 127

60 ml ICM (n = 70)

75 ml ICM (n = 57)

n/a

No significant difference of mean opacification values (HU) in the main, right and left PA between the test and control group for the optimally opacified scans.

Hendriks, et al. (2016) [56]

Prospective study

n = 100

High-pitch CTPA, individual body-weight adjusted ICM dose [42~76 ml] (n = 50)

High-pitch CTPA, 90 ml ICM [75 ml bolus and 15 ml mixed phase] (n = 50)

Diagnostic image quality for all scans in both groups. All scans were graded as “good” or “excellent” at each anatomic level, except one.

No significant difference in attenuation values between the control and test group. No non-diagnostic scans with a minimum mean PA attenuation of 184 HU and 270 HU for the control and the test group respectively. Acceptable CNR for both groups, but better for the test group.

Boos, et al. (2016) [57]

Retrospective study

n = 70

Low-pitch dual-source CTPA at 70 kVp, SimDS, 40 ml ICM (n = 35)

High-pitch dual-source CTPA at 100~120 kVp, ATPS,70 ml ICM (n = 35)

Diagnostic image quality for all examinations. No significant difference in subjective image quality between the control and test group.

Statistically significant difference between the two groups for the attenuation (HU) in the PT and LLSA. No statistically significant difference between the two groups for the SNR and CNR in the PT and LLSA.

Li, et al. (2015) [58]

Prospective study

n = 80

High-pitch dual-source CTPA at 70 kVp, SAFIRE reconstruction, 40 ml ICM (n = 40)

Low-pitch dual-source CTPA at 100 kVp, FBP reconstruction, 60 ml ICM (n = 40)

No significant difference in subjective image quality between the two groups. No difference in diagnostic accuracy between the two groups.

Higher CT values, SNR and CNR of PA in test group compared to control group.

Wang, et al. (2015) [59]

Prospective study

n = 60

Bolus triggering locator in the right atrium, spontaneous respiration, 40 ml ICM (n = 30)

Bolus triggering locator in the pulmonary trunk, suspended respiration, 70 ml ICM (n = 30)

Higher subjective image quality in the test group than the control group.

Significantly higher average CT values of main PA, RULA and RLPA and significantly lower CT values of AA, RUPV and RLPV in the test group than the control group. Significantly higher density between artery and vein pairs in the test group than the control group.

Szucs-Farkas, et al. (2014) [25]

Prospective randomized study

n = 501

80 kVp CTPA, 75 ml ICM (n = 246)

100 kVp CTPA, 100 ml ICM (n = 255)

No difference in subjective image quality and diagnostic confidence in both groups and all BW subgroups.

Decreased attenuation in the PT with increased BW in both groups. No differences in the PT attenuation between the two groups within each BW subgroup. Higher image noise in the test group in all BW subgroups. Higher CNR in the control group compared to the test group in all BW subgroups except for the 90-99 kg subgroup.

Lu, et al. (2014) [36]

Prospective study

n = 100

High-pitch CTPA at 80 kVp, SAFIRE reconstruction, 20 ml ICM (n = 50)

Low-pitch CTPA at 100 kVp, FBP reconstruction, 60 ml ICM (n = 50)

No significant difference in subjective image quality scores between two groups.

Higher mean CT numbers of PA in the test group compared to control group. Higher CNR and SNR of test group than those of control group.

Goble and Abdulkarim (2014) [60]

Retrospective study

n = 139

75 ml of 350 mg iodine/ml [26.25 gr iodine] ICM (n = 70)

100 ml of 300 mg iodine/ml [29.5 gr iodine] ICM (n = 69)

n/a

No significant difference in mean opacification of the main PA between the two groups. Significantly higher opacification in the right and left PA for the test group. No significant difference in the number of suboptimal opacified studies (opacification of less than 250 HU in main PA) between the groups.

Yuan, et al. (2012) [30]

Prospective study

n = 94

DE-CTPA, mixture of ICM and saline in 1:1 fashion resulting in 50% ICM dose and iodine load reduction and image reconstruction at 50 keV (n = 46)

Standard CTPA, undiluted ICM dose and 100 or 120 kVp tube voltage (n = 48)

Higher five-point score for standard CTPA image quality. Higher signal intensity in all PA, inferior noise only in segmental arteries, higher SNR and CNR for DE-CTPA.

n/a

Sodickson and Weiss (2012) [29]

Retrospective study

n = 152

100 kVp, 50 ml ICM (n = 53)

120 kVp, 75 ml ICM (n = 99)

n/a

Significant increase in main PA attenuation values by 96 HU and image noise for the test group compared to the control group. Comparable SNR for both groups.

Godoy, et al. (2011) [61]

Retrospective study

n = 50

Reduced contrast [RC] DE-CTPA [80-140 kVp], 50 ml ICM (n = 10)

DE-CTPA [80-140 kVp] CTPA (n = 20) and routine thoracic [RT] CT [80-140 kVp] (n = 20), 100~150 ml ICM

Significantly better central and peripheral vascular enhancement, image noise and global image quality scores in the 80 kVp images than 140 kVp images across all patient groups.

No significant difference in the SNRs in both 80 kVp and 140 kVp between either the CTPA and the RT group or the CTPA and the RC group.

Ramadan, et al. (2010) [62]

Prospective study

n = 90

60 ml (Protocol 1, n = 30), 55 ml (Protocol 2, n = 30), 50 ml (Protocol 3, n = 30) ICM

Comparison of image quality between the 3 protocols

All examinations evaluated as diagnostic in the subjective global image quality evaluation. Image quality was evaluated as diagnostic in 21 (23%) patients and excellent in 69 (77%) subjects. Subjective image quality was better in protocols 2 and 3 than in protocol 1.

Mean attenuation values for PA over 250 HU for all protocols. No difference between the attenuation levels between the three protocols. 90-100% success for protocols 2 and 3 where PA exceeds optimal attenuation (≥ 250 HU).