No abstract

This paper compares the capacity analysis suggested by the Federal Highway Administration (FHWA) roundabout guidelines with those of the Transportation Research Board (TRB draft report, 2006) and National Highway Cooperative Research Program (NHCRP report 572). The result will be given in term of average control delay time, 95th percentile queue length, and capacity of the critical lane in the critical approach, or the overall approach depending on the method used.

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Basilar artery dolichoectasia (BAD) is a disorder characterized by dilatation, elongation and tortuosity of the basilar artery. Transcranial Doppler ultrasound (TCD) is a useful tool that can detect blood flow in intracranial vessels including basilar artery (BA). Few studies have been conducted on blood flow changes in BAD. This study was conducted to evaluate the Doppler parameters in dolichoectatic BA and to assess if there is any difference in TCD findings between stroke and non-stroke BAD patients. A case-control study was conducted on 35 patients diagnosed with BAD (26 male, 9 female) and 35 age- and gender-matched control group (without BAD) at the Middle Euphrates Neuroscience Center, Al-Sader Medical City, Al-Najaf, Iraq. Dolichoectasia was diagnosed on non-enhanced brain CT scan using established imaging criteria according to Dan Deng et al criteria. Doppler flow for control and stroke cases was recorded. The parameters measured on TCD were peak systolic velocity (PSV), end diastolic velocity (EDV) mean blood velocity (MBV), pulsatility index (PI) and resistive index (RI). After logistic regression for adjustment for the significant confounders, there was statistically significant difference in Doppler parameters between both groups including decrease in each of PSV, EDV and MBV while both PI and RI weren’t statistically significant. Among BAD patients, there was statistically significant difference in all TCD parameters between stroke and non-stroke patients (PSV EDV, MBV, PI and RI). BAD was associated with a decrease in flow velocities as measured by TCD. Furthermore, among BAD patients, those with stroke had lower values for all Doppler parameters than non-stroke patients.