How does the blood leave the brain? A systematic ultrasound analysis of cerebral venous drainage patterns

Abstract

The internal jugular veins are considered to be the main pathways of cerebral blood drainage. However, angiographic and anatomical studies show a wide anatomical variability and varying degrees of jugular and non-jugular venous drainage. The study systematically analyses the types and prevalence of human cerebral venous outflow patterns by ultrasound and MRI. Fifty healthy volunteers (21 females; 29 males; mean age 27+/-7 years) were studied by color-coded duplex sonography. Venous blood volume flow was measured in both internal jugular and vertebral veins in the supine position. Furthermore, the global arterial cerebral blood volume flow was calculated as the sum of volume flows in both internal carotid and vertebral arteries. Three types of venous drainage patterns were defined: a total jugular volume flow of more than 2/3 (type 1), between 1/3 and 2/3 (type 2) and less than 1/3 (type 3) of the global arterial blood flow. 2D TOF MR-venography was performed exemplarily in one subject with type-1 and in two subjects with type-3 drainage. Type-1 drainage was present in 36 subjects (72%), type 2 in 11 subjects (22%) and type 3 in 3 subjects (6%). In the majority of subjects in our study population, the internal jugular veins were indeed the main drainage vessels in the supine body position. However, a predominantly non-jugular drainage pattern was found in approximately 6% of subjects.

Incidence of Extrinsic Compression of the Internal Jugular Vein in Unselected Patients Undergoing CT Angiography

“…When humans are upright, the predominant venous drainage of the brain is via the vertebral venous plexus, rather than the internal jugular vein. [12][13][14][15] In contrast, the jugular veins are the dominant drainage for the supine patient. 12,15 One described major connecting pathway is the anterior condylar confluence, which has been shown to have connections between the jugular bulb and the anterior, lateral, and posterior condlylar veins, and may have a significant role in the postural redirection of flow.…”

Human cerebral arteriovenous vasoactive exchange during alterations in arterial blood gases

“…However, several authors showed that venous outflow may be influenced by posture and anatomic variability (14,54), raising the potential for nonjugular venous drainage to result in an underestimation of vasoactive agents. Unfortunately, these authors (14, 54) did not perform angiographic studies; however, Doepp et al (14) reported that the internal jugular veins were the main source of venous drainage in 72% of their supine healthy volunteers.…”

“…The extracted NT-CNP was added to primary rabbit antiserum (J39) raised against NT-proCNP-(1-15) (1:6,000 dilution, 100 l antiserum/assay tube). Peptide standards were made from synthetic human proCNP- (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15), with the purity data supplied by the manufacturer (Chiron Technologies) taken into account. Within-and between-assay CVs were 6.0% and 7.9%, respectively.…”

Cerebral venous overdrainage: an under-recognized complication of cerebrospinal fluid diversion

“…28,82 In a systematic ultrasonography and MRI analysis of the types and prevalence of human cerebral venous outflow, it was shown that there is predominantly jugular drainage in 72% of healthy volunteers. 26 In 22% the jugular drainage equals the nonjugular drainage, and in 6% the drainage pattern is nonjugular. These findings suggest that in the general population there are variations in the anatomy of cranial venous outflow.…”

“…26,36,63 A marked increase in central venous pressure, such as any Valsalva maneuver, completely reopens the internal jugular veins. 26 In an ultrasonography study of the postural dependency of venous outflow, it was shown that blood flow in the internal jugular veins decreases from 700 ml/min in the supine position to 70 ml/min at 90° elevation while flow in the vertebral veins is increased from 40 to 210 ml/min. 85 Total venous outflow declines from 740 to 280 ml/min from 0° to 90°, with the largest decrease at 15°.…”