The aims of this study are to understand the contribution of celiac and mesenteric areas on the hypertension and to investigate the flow regulation mechanisms in celiac area. In conscious spontaneously hypertensive rats (SHR) and normotensive control rats (NCR), regional blood flow and arterial pressure were observed with an implanted electromagnetic flow probe and an indwelling arterial catheter. Regional resistance was calculated as arterial pressure divided regional flow. The contribution of celiac area on the hypertension was below the average for the whole body. Ganglionic blockade with hexamethonium bromide decreased celiac resistance (CeR) more markedly in SHR than NCR, which suggests an important role of sympathetic nerves in the increase in CeR in SHR. Autoregulation did not play any part in the elevation of CeR, while the participation of flow superregulation was suggested in the elevation of mesenteric resistance.

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Purpose: Phase-contrast magnetic resonance angiography (PC-MRA) is a noninvasive technique which allows the measurement of blood velocity and velocity profile in the major intracranial vessels. Authors applied PC-MRA to the analysis of hemodynamic changes in major cerebral vessels in patients with cerebrovascular diseases.
Materials and Methods: Four healthy human volunteers and 16 patients with cerebral infarction, cerebral aneurysm, and arterio-venous malformation were examined with a 1.5 Tesla superconducting imaging system. Phase-contrast cine technique was applied to the measurement of blood flow. The data on blood velocity obtained from healthy volunteers were compaired with those measured with transcranial Doppler urtra-sonography (TCD).
Results: As to blood velocity in common carotid, internal carotid, external carotid, and middle cerebral arteries of healthy volunteers, linear relationships were obtained between the values measured with PC-MRA and those with TCD. The flow velocity distribution in the lumen of aneurysmal sac was evaluated with PC-RMA in 4 of 5 cases. In arterio-venous malformation, the flow pattern of feeding arteries were demonstrated with PC-MRA. In occlusive cerebrovascular diseases, flow pattern specific to post-stenotic region in arteries were estimated with PC-MRA.
Conclusion: PC-MRA is a noninvasive and useful method for evaluation of cerebral hemodynamics in patients with cerebral aneurysm, arteriovenous malformation, and occlusive cerebrovascular diseases.

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An analytical model of the pulsatile flow, which oscillates the two stenotic walls outside of it, is presented. This two-dimensional calculation has made it possible to compare symmetric flow and non-symmetric one. The resultant analytic functions also distinguish the effects of the degree of the stenosis. The condition of the self-consistent oscillation seems to break up in the case of high-Reynolds flow. A little difference between the wall-stress on the symmetric stenosis and that of non-symmetric one seems to affect the deformation of the stenoses.

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