Twenty-six patients who had undergone recent surgery for differentiated thyroid cancer were investigated using iodine-131 iodide (120 MBq). Uptake in the thyroid bed was measured at 3 days using a dual-head gamma camera. An ablation activity of 131I iodide (4,000 MBq) was administered 3-38 (median 14) days later and uptake in the thyroid bed measured once or twice, 1-3 days post therapy. For measurements post therapy, the gamma camera was operated in the high-count rate mode with appropriate correction factors to compensate for any count loss. A further 16 patients were given iodine-123 iodide (200 MBq) as the diagnostic agent and uptake was measured at 24 h. The ablation activity was administered 5-47 (median 19) days later and uptake again measured at 24 h. In some cases, a further measurement of uptake was made within the period 1-3 days post therapy. Reduced uptake of the therapeutic administration ( P<0.001) was observed in all 26 patients given diagnostic 131I, with a median value of 32.8% (range 6%-93%) of the uptake in the diagnostic study. In the patients given diagnostic 123I, reduced uptake of the ablative radioiodine was observed in 15 of the 16 patients ( P<0.001), and overall the median value was 58.8% (range 17%-130%) of the diagnostic uptake. In one case the uptake post therapy was increased. The stunning observed in the group given 123I was significantly less ( P<0.001) than in the group given 131I. In the patients given diagnostic 131I, stunning appeared to increase in severity the longer the time interval between the diagnostic and therapeutic radionuclides, for intervals up to 25 days. Thereafter, there seemed to be some recovery of uptake capability. Overall there was no evidence of a large rapid loss of radionuclide from the thyroid bed 1-3 days post therapy. The stunning observed using 123I could not be explained by errors in the estimation of relative uptake due to different tissue absorption of the 131I and 123I photons, nor by the radiation dose delivered by the 123I. However, the ablative 131I itself may cause stunning because the cumulated activity, over the first few hours of uptake, is not insignificant when compared with all the cumulated activity from a diagnostic administration of 131I. The resultant radiation dose to the thyroid remnant, as the therapeutic radioiodine is being taken up, may be sufficient to inhibit the uptake process, thus leading to a reduction in maximum uptake when compared with that of a diagnostic activity of radioiodine.

Background and Purpose-The purpose of this study was to investigate the effect of the angiotensin-converting enzyme inhibitor perindopril on mean arterial blood pressure (MABP), cerebral blood flow (CBF), and glomerular filtration rate in hypertensive stroke patients with moderate to severe internal carotid artery (ICA) disease or ICA occlusion. Methods-Twenty-four nonacute ischemic stroke patients who had MABP readings Ͼ100 mm Hg and moderate to severe ICA stenosis or occlusion were randomized to receive perindopril 4 mg daily or placebo for 14 days. MABP, ICA flow, and both middle cerebral artery (MCA) velocity and resistance index were measured before dose, at 5 time points over the subsequent 24 hours, and finally at 2 weeks. Brain hexamethyl propylene amine oxide single photon emission computed tomography scans were performed before drug administration and at time of peak drug effect (6 to 8 hours) after the first dose. Glomerular filtration rate was measured with 51 Cr EDTA before medication and at 14 days. Results-A placebo-corrected BP fall of 17/10 mm Hg was seen (Pϭ0.017), which was maximal at 5.5 hours. No significant change in ICA flow or MCA velocity was seen between groups. No significant change in hemispheric CBF was seen. The mean change from baseline in the treated group was Ϫ0.79 mL · 100 g Ϫ1 · min Ϫ1 (95% confidence interval [CI], 1.65 to Ϫ3.23); mean change in the placebo group was Ϫ1.9 mL · 100 g Ϫ1 · min Ϫ1 (95%CI, 3.02 to Ϫ6.92). Peri-infarct CBF was similarly unaffected. One of the treated patients developed transient acute renal impairment and was withdrawn from the study on day 4. Conclusions-Perindopril

Losartan may be introduced within 2-7 days of mild stroke in hypertensive patients in whom significant carotid occlusive disease has been excluded without affecting global or regional CBF, or affecting GFR.

Background and Purpose: Blood pressure reduction is central to secondary prevention after stroke, but the optimal time to start therapy is unknown. Cerebral autoregulation is impaired early after ischaemic insult, and any changes in systemic blood pressure may be reflected in cerebral perfusion. However, early initiation in hospital may better assure continued long-term treatment. We have investigated the effect of the angiotensin-converting enzyme inhibitor perindopril on blood pressure, global and focal cerebral blood flow (CBF) and glomerular filtration rate (GFR) in a normotensive acute stroke population. Methods: Twenty-five patients within 4–8 days of mild ischaemic stroke/transient ischaemic attack and with diastolic blood pressure 70–90 mm Hg were randomized to receive perindopril 2 or 4 mg daily versus placebo according to estimated GFR. Mean arterial blood pressure (MABP), internal carotid artery (ICA) flow and middle cerebral artery velocity (MCAv) were measured prior to dosing, over the following 24 h and at 2 weeks. Brain hexamethyl propylene amino oxide single photon emission computed tomography (SPECT) was performed before dosing and at estimated time of peak drug effect (6–8 h after first dose). GFR measurement using a ⁵¹Cr-ethylene diamine tetraacetic acid technique was undertaken prior to medication and repeated at 2 weeks. Results: MABP was reduced throughout the first 24 h with a mean MABP reduction of 9.3 mm Hg (95% CI 7.4–11.3 mm Hg), maximal placebo corrected fall of 12.5 mm Hg at 10 h post-dose, p = 0.005. No significant change occurred in ICA flow, MCAv or CBF measured by SPECT: change from baseline in symptomatic hemisphere CBF was –0.02 (SD 3.11) ml/100 g/min (treated group) compared with 0 (SD 3.01) (placebo group). Similarly, no significant change was observed in cortical CBF. Mean within-group change in GFR was 2.7 ± 10.1 in the treated group and –4.3 ± 6.7 in the placebo group (p = NS). Discussion: Antihypertensive therapy with perindopril may be introduced in the first week after mild ischaemic stroke in normotensive patients without affecting global or regional CBF or affecting GFR.

Single-photon emission tomography (SPET) is widely used in the investigation of acute stroke. We investigated the relationship between SPET data and functional outcome in a large group of acute stroke patients. One hundred and eight patients underwent cerebral computed tomography (CT) and technetium-99m hexamethylpropylene amine oxime SPET after acute ischaemic stroke. We categorised the clinical presentation according to the Oxford classification of acute stroke. Outcome was measured 1 year after stroke using mortality and the Barthel Index for survivors. SPET scans were interpreted without reference to the clinical data using a semi-automatic technique. Three experienced observers determined the presence of luxury perfusion using suitably scaled SPET images in conjunction with the CT scan. Both SPET volume and severity of deficit were significantly negatively correlated with Barthel Index at 1 year (rs=-0.310, P<0.0001, and rs=-0.316, P<0.0001 respectively). In patients scanned with SPET within 16 h of stroke onset, the correlations were more strongly negative (rs=-0.606, P<0. 001, and rs=-0.492, P<0.005 respectively). Luxury perfusion was not associated (chi2=0.073, df=1, P=0.79) with good functional outcome (Barthel score >/=60). Stepwise logistic regression identified Oxford classification, total deficit volume and patient's age as significant predictors of functional outcome. Overall predictive accuracy was 72%. Predictive accuracy was better in patients who received SPET within 16 h of stroke onset. SPET provides useful information about the functional outcome of acute stroke at 1 year. However, the accuracy of prediction decreases the longer SPET is delayed. Prognostication using SPET in combination with clinical assessment and other investigations may also be considered.