Contrast-enhanced 2D cine phase MR angiography for measurement of basilar artery blood flow in posterior circulation ischemia

Abstract

Background and purpose: Dizziness is a symptom that develops with internal ear disturbances and with dysfunctions of the brain stem and cerebellum, in particular with blood flow disturbances of the brain stem and cerebellum (posterior circulation ischemia [PCI]). Patients with PCI often present with various neurologic signs and symptoms. To examine the usefulness of contrast-enhanced 2D cine phase MR angiography in the diagnosis of PCI, we examined quantitative blood flow of the basilar artery in patients with PCI who had primarily complained of dizziness.

Methods: We quantitatively measured the blood flow volume rate of the basilar artery by using a contrast-enhanced 2D cine phase MR angiographic technique in 21 patients diagnosed with PCI and in 16 age- and sex-matched control participants.

Results: Maximum and mean average flow velocities of the basilar artery in the PCI group were significantly lower than those of the control group (29.2 +/- 9.2 cm/s versus 38.5 +/- 8.2 cm/s [P <.005] and 18.0 +/- 5.6 cm/s versus 22.6 +/- 5.0 cm/s [P <.01], respectively). The flow volume rates of the basilar arteries were also significantly lower in the PCI group (103.3 +/- 37.3 mL/min versus 148.8 +/- 40.0 mL/min [P <.001]).

Conclusion: The flow volume rate of the basilar artery in patients with PCI during intermittent ischemic attacks with dizziness was chronically reduced compared with that in the control participants. This suggests that flow volume rates may influence the development of the clinical signs and symptoms of PCI. We think that contrast-enhanced 2D cine phase MR angiography is a valuable method for the diagnosis of PCI.

Fig 1.

Gradient recalled acquisition in the steady state and contrast-enhanced 2D cine phase MR images. A, For the determination of the transverse image plane, a sagittal gradient recalled acquisition in the steady state MR image (20/5; flip angle, 60 degrees) was created. The imaging plane was determined at the midpontine level to be perpendicular to the basilar artery. B, Contrast-enhanced 2D cine phase MR image (40/11.8; flip angle, 30 degrees), acquired at 32 phase. Note the basilar artery as an area of hypointensity (arrow).

Fig 2.

3D time-of-flight MR angiograms and blood flow velocity data plots. A, 3D time-of-flight MR angiogram (33/4; flip angle, 20 degrees) of a 49-year-old male patient with PCI and dizziness shows narrowing of the right vertebral and basilar arteries. Change of blood flow velocity between systolic and diastolic phases was greater in the patient than in the normal control volunteer (see B). B, 3D time-of-flight MR angiogram (33/4; flip angle, 20 degrees) of a 54-year-old female control participant with no clinical signs or symptoms shows mild meandering of the basilar artery.