Case Report Cerebrovasc Dis 1999;9:351–354 Received: February 8, 1999 Accepted: March 1, 1999 Hyperacute Diffusion-Weighted MRI in Basilar Occlusion Treated with Intra-Arterial t-PA N. Nighoghossian a L. Derex a F. Turjman b J. Honnorat a P. Lucain b Y. Berthezene b F. Artru c J.C. Froment b P. Trouillas a a Cerebrovascular Disease and Ataxia Research Center, b Department of Radiology, Creatis UMR CNRS 5515, and c Intensive Care Unit, Lyon, France Abstract Basilar artery thrombosis should be diagnosed immediately, as intra-arterial thrombolysis might improve the outcome. Diffusion-weighted (DWI)-MRI and three-dimensional time-of-flight MR angiography (3D TOF Turbo MRA) may provide additional insight into the extent of ischemia and the level of the occlusion. These methods could be helpful in the early classification of vertebrobasilar stroke, thus reserving the use of conventional angiography and possible intra-arterial thrombolysis for patients who had a severe clinical picture explained by preliminary assessments. We report the case of a 74-yearold woman who experienced a basilar artery occlusion; DWI-MRI and 3D TOF Turbo MRA provided noninvasive information concerning the level of arterial occlusion and its parenchymal ischemic impact, this leading to an intra-arterial thrombolytic therapy. These data suggest the feasibility of a noninvasive urgent diagnostic and prognostic approach with DWI-MRI and 3D TOF Turbo MRA in basilar occlusion. ABC © 1999 S. Karger AG, Basel 1015–9770/99/0096–0351$17.50/0 Fax + 41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Accessible online at: www.karger.com/journals/ Introduction Within the spectrum of vertebrobasilar ischemic stroke, basilar artery thrombosis remains a highly fatal disease [1, 2]. This neurological emergency [3] should be diagnosed immediately, as intra-arterial thrombolysis is a promising therapeutic method [4–6]. Cerebral angiography is an integral part of this procedure and allows the visualization of the occlusion, but does not quantify brain tissue ischemia. Diffusion-weighted (DWI)-MRI and three-dimensional time-of-flight MR angiography (3D TOF Turbo MRA) may provide additional insight into the extent of ischemia and the level of the occlusion. These new MRI methods may allow a better classification of patients before an invasive procedure is started. Most DWI-MRI studies have dealt with acute anterior circulation strokes [7–11], but data concerning posterior circulation strokes are scarce. We report a patient with basilar artery occlusion in whom DWI-MRI and MRA provided noninvasive information concerning the level of arterial occlusion and its parenchymal ischemic impact. Dr. N. Nighoghossian Service d’Urgences Cérébrovasculaires, Prof. P. Trouillas Hôpital Neurologique, 59, bd. Pinel F–69003 Lyon (France) Fax +33 7 27 35 73 29 Downloaded by: Kaohsiung Medical University Library 163.15.154.53 - 4/21/2018 4:30:07 PM Key Words Basilar occlusion W Diffusion-weighted MRI W Three-dimensional time-of-flight MR angiography a b Fig. 1. a T2-weighted MRI showing mild ischemic abnormalities within the cerebellum. b Acute DWI-MRI with abnormalities suggesting severe vertebrobasilar ischemia. MRI was performed on a 1.5-Tesla unit (Siemens AG, Erlangen, Germany) with a circularly polarized head coil. In addition to diffusion-weighted echo-planar imaging (DWI-EPI), a T2-weighted Turbo spin echo (T2 TSE) and a 3D TOF Turbo MRA were acquired. The technical parameters were as follows: T2 TSE: TR 3,000 ms; TE 98 ms; flip angle 180°; matrix 200 ! 512; field of view 250 mm; excitation 2; 20 axial slices; slice thickness 5 mm; acquisition time 4 min 7 s. 3D TOF Turbo MRA: TR 35 ms; TE 6.4 ms; flip angle 20°; matrix 160 ! 512; field of view 230 mm, excitation 1; acquisition time 6 min 14 s. Three axial slabs (thickness 31.9 mm; partition 24; distance factor –0.38) were placed over the entire circle of Willis. MIP reconstruction was used for postprocessing. EPI isotropic diffusion: TR 4,700 ms; TE 118 ms; 20 axial slices; thickness 5 mm; matrix 96 ! 128; field of view 230 mm; excitation 1; acquisition time 23 s; two b values were used (0 and 1.000 s/mm2) 352 Cerebrovasc Dis 1999;9:351–354 on vision system. The MR diffusion sequence at b = 1.000 was run three times with diffusion gradients applied in each of the x, y, and z directions. Case Report On Tuesday 4th May 1998, at 4 p.m., a 74-year-old right-handed hypertensive woman experienced suddenly a left peripheral facial palsy associated with a severe dysarthria; she was admitted to our stroke unit 4 h later. At 8.30 p.m. her neurological status worsened, she was totally unresponsive with complete ophthalmoplegia, tetraplegia and bilateral Babinski sign. Monitored blood pressure was 210/120 mm Hg. Body temperature was 37.5 ° C. Cardiovascular examination, ECG, chest X-ray, serum electrolytes and blood sugar levels, routine coagulation studies and early CT scan were normal. MRA and DWI-EPI were performed 25 min after neurological deterioration and 4 h and 55 min after stroke onset. Conventional T2- Nighoghossian/Derex/Turjman/Honnorat/ Lucain/Berthezene/Artru/Froment/ Trouillas Downloaded by: Kaohsiung Medical University Library 163.15.154.53 - 4/21/2018 4:30:07 PM MRI Studies b a Fig. 2. a Baseline 3D TOF MRA showing a defect consistent with an intraluminal basilar thrombus. b Conventional angiography showing a floating thrombus within the midbasilar artery. Fig. 3. Day 1 CT scan showing an extensive infarct within the vertebrobasilar territory. DWI-MRI in Basilar Occlusion Discussion The successful t-PA NINDS trial [12] opens a new era of early stroke management involving the role of new functional imaging technologies [13]. Clinical examination and CT scan data inadequately assess the extent of ischemia in posterior-circulation stroke at the very early stage, in contrast to anterior-circulation ischemia [14]. In Cerebrovasc Dis 1999;9:351–354 353 Downloaded by: Kaohsiung Medical University Library 163.15.154.53 - 4/21/2018 4:30:07 PM weighted MRI showed slight abnormalities, whereas DWI-MRI showed a very large area of ischemia within the vertebrobasilar territory (fig. 1); 3D TOF Turbo MRA disclosed a floating thrombus within an atherosclerotic basilar artery. This aspect was confirmed by cerebral angiography 30 min after the MRI studies (fig. 2). Intraarterial t-PA up to 60 mg was administered over 1 h via a selective catheter into the clot while blood pressure was controlled; recanalization was not achieved and the patient developed an extensive pons, midbrain and cerebellar infarction (fig. 3). She died on day 4. the present case, the initial CT scan was normal, follow-up CT scan showed an extensive infarction highly consistent with the DWI-MRI abnormalities disclosed on admission. As expected the ischemic area was betted delineated by DWI-MRI than by conventional T2 sequences. These preliminary data show that very early (less than 6 h) DWIMRI abnormalities may be highly predictable of brain territory at risk of subsequent infarction in basilar artery occlusion; nevertheless, areas of altered diffusion on DWI-MRI are not steadily correlated with irreversible damage. Though these new functional imaging technologies are not essential for the diagnosis of basilar thrombosis in a typical case, the addition of DWI-MRI and 3D TOF Turbo MRA did not delay significantly the initiation of cerebral angiography and intra-arterial thrombolysis (DWIMRI and 3D TOF Turbo MRA were performed 4 h and 55 min after stroke onset, and time from MRI studies to angiography was 30 min). Accordingly, these methods could be helpful in the early classification of vertebrobasilar stroke, thus reserving the use of conventional angiography and possible intra-arterial thrombolysis for patients who had a severe clinical picture obviously explained by these preliminary assessments. 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