Impact of 80 kVp with iterative reconstruction algorithm and low-dose contrast medium on the image quality of craniocervical CT angiography

Double low-dose computed tomography (CT) angiography of craniocervical arteries using a test bolus of diluted contrast medium and a personalized contrast protocol

AIM

To prospectively assess the value of a test bolus of diluted contrast medium (CM) combined with a personalized contrast protocol in craniocervical computed tomography angiography (cc-CTA) with low radiation and CM doses.

MATERIALS AND METHODS

Eighty-six consecutive subjects were divided into two groups at random (43 in each one): group A: 100/Sn140 kVp, filtered back-projection reconstruction, iopromide (370 mgI/ml) 50 ml; group B: 80/Sn140 kVp, iterative reconstruction, iodixanol (270 mgI/ml). In group B, the test bolus contained 27 ml of diluted CM, a personalized protocol with low-concentration CM was used for angiography, and the test bolus injection duration in angiography remained the same. Artery values over 200 Hounsfield units were considered significant.

RESULTS

Image quality for all cases was found to be diagnostic. No significant differences were found in the arterial densities of the ascending aorta or basilar artery between the groups. The values of the common carotid artery, internal carotid artery, and middle cerebral artery in group B were significantly lower. The effective dose and average iodine uptake were significantly lower in group B.

CONCLUSION

With double-low-dose cc-CTA, test bolus scanning based on diluted CM combined with a personalized contrast protocol can yield diagnostic-quality images and significantly reduce the radiation and CM doses.

Enhancing acute stroke assessment: evaluating the clinical utility of the "Real" one-stop-shop scan protocol combining brain computed tomography perfusion and head-and-neck computed tomography angiography using a 512-slice detector computed tomography scanner

AIM

To assess the efficiency and diagnostic value of the "real" one-stop-shop protocol integrating the computed tomography angiography (CTA) sequence of the head and neck into the computed tomography perfusion (CTP) acquisition using a 512-slice detector CT scanner in patients who suffered from acute ischemic stroke.

MATERIALS AND METHODS

This prospective study included 100 patients suspected of acute ischemic stroke. The patients were randomly divided into two groups: the control group (n=50) who underwent the traditional protocol (brain CTP and head-and-neck CTA examination separately) and the experimental group (n=50) who underwent a one-stop-shop protocol (combined brain CT perfusion and head-and-neck CTA, the CTA triggering time determined by a low-dose test bolus injection). The examination time, contrast-agent dosage, radiation dose, postprocessing time, and image quality were compared between the two groups.

RESULTS

Compared to the control group, the experimental group had a significantly lower total iodine contrast-agent dosage (80 vs. 100 ml, P<0.001) and shorter scan time (3.23 [3.13, 3.35] vs. 2.32 [2.17, 2.45] min, P<0.001). Additionally, the radiation dose exposure was lower in the experimental group than in the control group (5129.00 [5173, 5232] vs. 4681.35 [4555.12, 4822.95] mGy-cm, P<0.001). No statistically significant differences were observed between the two groups in terms of postprocessing time, head-and-neck CTA, and CTP imaging quality.

CONCLUSION

The one-stop-shop protocol enables effective detection of lesions, providing clear visualization of the location and degree of stenosis in the head-and-neck vessels. It achieves this with lower costs in scan time, contrast-agent dosage, and radiation dose compared to the traditional protocol and is thus worth considering as the first examination for patients who suffer from acute ischemic stroke.

Low-dose three-dimensional CT angiography for the evaluation of posterolateral protrusion of the vertebral artery over the posterior arch of the atlas: a quantitative anatomical comparison study of the rotational and neutral positions

AIM

To investigate the changes in relevant anatomical parameters of posterolateral protrusion of the vertebral artery (VA) between head-neck rotational and neutral positions using low-dose three-dimensional computed tomography angiography (3D-CTA).

MATERIALS AND METHODS

Low-dose 3D-CTA images obtained for various craniocervical diseases in 36 non-dominant VA side patients with neutral, left and right head-neck rotational positions were evaluated. The relevant parameters from superior and inferior views, including external diameter (ED), internal diameter (ID), transverse diameter (TD), heights and diameters of posterolateral protrusion of the VA over the posterior arch of the atlas in the neutral and rotational positions, were recorded and compared.

RESULTS

There was no significant differences in the rotational angle (left/right: 31.23 ± 6.60/29.94 ± 6.09°, p>0.05). There were no significant differences in heights and diameters of bilateral VA between rotational and neutral positions (all p>0.05). The contralateral ID, ED, and TD of the rotational positions were significantly shorter than those of the neutral position (all p<0.05), while there were no significant differences in the three ipsilateral diameters (all p>0.05).

CONCLUSIONS

Posterolateral protrusion of the VA is not uncommon in the population, and surgeons should be aware of its presence, especially the increased possibility of injury to the VA caused by head-neck rotation, during the operation; thus, preoperative evaluation by low-dose 3D-CTA should be considered.