SUMMARY Regional cerebral blood flow (rCBF) was studied using SPECT (single photon emission computed tomography) with 133-Xenon in 13 patients with confirmed Sturge-Weber disease, aged 9 months to 18 years. CT scan, performed at the same time, showed evident cerebral angioma in 10 but not in three. A marked hypoperfused area was found in all patients, ranging from -32% to -72% and of the same location as the CT signs. The hypoperfusion seems to result from post ictal phenomenon as well as from chronic ischaemia. SPECT imaging is therefore a sensitive method for visualising intracranial angioma in Sturge-Weber disease and it provides an aid for diagnosis when a CT scan is not reliable.Sturge-Weber (SW) angiomatosis is a non-inherited neurocutaneous syndrome characterised by a congenital trigeminal port-wine stain and a piamater angioma.' This intracranial angioma, venous and purely meningeal,23 is embryologically derived from the neural crest. Along with the angioma, cerebral lesions, which are ischaemic in nature, are seen in the cortex underlying the angioma.4

Seventeen chronic cerebral Infarcts were investigated by a highly sensitive, dedicated brain single photon emission computerized tomography system using li3 I-isopropyl iodoamphetamine (IMP) and LU Xe. IMP uptake was measured 10 minutes, 2 hours, and 5 hours after injection, and regional cerebral blood flow was measured with 133 Xe. In 4 cases a positron emission tomography system was used to measure the rCBF and the regional metabolic rate of oxygen with C 15 O 2 and '*O 2 -The results obtained allowed us to identify 2 abnormal zones. One, the "central area," was characterized by a severe decrease in IMP uptake and rCBF averaging 34% and 46% respectively and by a hypodense image on the x-ray computerized tomography scan. The second, the periinfarct or "peripheral area" was characterized by a moderate decrease in IMP uptake and regional cerebral blood flow averaging 13 and 19% respectively; this area extended around the central area and had a normal density on computerized tomography scan. The IMP hypofixation of the peripheral area observed at the 10th minute tended to disappear at the 5th hour. The volume of this area was often found to be quite large, covering more than 30% of a hemisphere whereas the central area did not exceed 25%. C EREBRAL single photon emission tomography (SPECT) has benefited from two major improvements in recent years. The first was the advent of I-123-isopropyl-iodoamphetamine (IMP), which can be considered the first real brain agent 1 placed at the disposition of every nuclear medicine center. Its usefulness is recognized in cerebrovascular patients in obtaining both the localization and the extent of infarcts whether such infarcts are visible or not by x-ray computerized tomography (CT).2 " 7 The second was the introduction of a high-sensitivity SPECT system. 89 Because its sensitivity is so much higher than that of rotating cameras, acquisitions take only a few minutes and can be repeated easily. With this system, regional cerebral blood flow (rCBF) measured with 133 Xe and IMP values can be obtained on the same areas of the tomographic slices.Using this high-sensitivity SPECT system we studied 17 patients with chronic infarcts; a few were also studied with a positron emission tomography (PET) system. The results obtained emphasize the pathophysiological importance of the periinfarct area in Received October 18, 1985; accepted July 29, 1986. which IMP uptake, CBF, and metabolic activity are decreased. Subjects and MethodsTwo SPECT systems were used. All patients were studied with the Tomomatic 64, a hybrid bar-camera array system; a few were also studied using a rotating camera (GE-400 A) connected to a SIMIS 4 computer. Physical characteristics of both systems have been described in detail elsewhere.8 "" We will only detail here the "relative ' sensitivity of the Tomomatic, which we found to be 20-25 times higher than that of the GE-400 A for 123 I allowing for shorter acquisition times. With both systems "relative" sensitivity represents the count number of a 2-cm-thick...

We measured regional cerebral blood flow and [ ]iodoamphetamine (IMP) uptake, in regional cerebral blood flow (rCBF), and in regional cerebral metabolic rate for oxygen (rCMROi), corresponding to the infarct core and hypodensity on the x-ray computed tomogram (CT scan). The peripheral or peri-infarct area was characterized by slight decreases in IMP uptake, rCBF, and rCMRO 2 , with a normal image on the x-ray CT scan that we attributed to diaschisis or selective neuronal loss and not to a chronic ischemic penumbra.We studied the central and peripheral areas during the subacute period using single-photon emission computed tomography (SPECT) once, twice, or more times, providing a longitudinal evaluation of both areas. A few patients were also studied using positron emission tomography (PET), providing information on rCMRO 2 in the same areas. The Received August 5, 1987; accepted August 15, 1988. data were analyzed with attention to the pathophysiology of alteration in the peri-infarct areas. Subjects and MethodsEach patient had a SPECT study with xenon-133 and one with IMP using a Tomomatic 64 providing three slices with 17 mm resolution and later using a Tomomatic 564 providing five contiguous slices with 12 mm resolution. 23 rCBF was measured in each patient as described elsewhere, 4 -6 and results were expressed in milliliters per minute per 100 grams of brain or relative to the contralateral symmetrical value. rCBF was also measured 30 minutes after intravenous injection of 1 g acetazolamide. The normal rCBF increase induced by the drug (acetazolamide reactivity) was found to be approximately 30% 7 ; mean±SD acetazolamide reactivity was 38±19% in the assumed normal hemisphere of 49 patients in our center.IMP images were routinely obtained 10-30 minutes (IMP 10') and then 5 (IMP 5H) and 24 (IMP 24H) hours after injection. IMP was prepared from a commercial kit (Oris, CEN-Saclay, France) with iodine-123 that was produced by a tellurium-124 (p,2n) iodine-123 reaction and contained <4% iodine-124. Doses injected were 185-259 MBq (5-7 mCi) in 10 mg IMP. IMP uptake results were not corrected for isotope decay and are expressed relative to the contralateral symmetrical value.Three patients had a PET study of rCBF, rCMRO 2 , and regional oxygen extraction fraction

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