Differentiation Between Intracerebral Hemorrhage and Ischemic Stroke by Transcranial Duplex Sonography
To the Editor:
In their recent article,1 Mäurer and colleagues concluded that (1) transcranial color-coded duplex sonography (TCCS) identified stroke complications and differentiated between intracerebral hemorrhage and ischemic stroke with reasonable sensitivity and specificity when compared to computed tomography (CT) of the brain, (2) TCCS may substitute for CT if CT service is not readily available, and (3) TCCS may be used to monitor stroke complications. I would raise the following comments.
The differentiation between intracerebral hemorrhage and ischemic stroke has critical implications for stroke management because of the recent breakthrough in acute therapy of ischemic stroke with tissue plasminogen activator.2 3 4 A prior neuroimaging with CT or MRI is mandatory, because thrombolysis in intracerebral hemorrhage is definitely contraindicated and inappropriate.5 Differentiation between subtypes of ischemic stroke and determination of the underlying pathogenic mechanisms are not indicated in the acute stage because precious time should not be wasted.6 Signs of extensive infarction on neuroimaging would exclude the patient from receiving tissue plasminogen activator, since the risk of symptomatic hemorrhagic transformation would outweigh the potential benefit of revascularization.5 On the other hand, ongoing major clinical trials on neuroprotective therapy in acute stroke permit inclusion of patients with intracerebral hemorrhage.7 8 The rationale is to test whether the neuroprotectants are safe and/or effective in intracerebral hemorrhage and whether these drugs can be given by the staff of the emergency medical services before arrival to the hospital. Thus, acute thrombolysis cannot be advised if CT or MRI is not available, and neuroprotectants (if efficacy is proved by clinical trials) may be considered without CT and MRI. In either situation, TCCS has no added value. In addition, TCCS cannot detect signs of early infarction.
Time is another critical factor in acute stroke therapy.5 6 The authors recommended examination of both hemispheres by TCCS and noted that poor acoustic bone windows may preclude TCCS examination in about 15% of stroke patients.1 I am interested in knowing the time required to finish the TCCS examination. It is important to note that the TCCS examination was done at least 24 hours after admission and that CT was done before the TCCS examination in 85 patients. I would like to know the time interval between CT and TCCS, since hematoma enlargement with time could facilitate the detection of hematoma.9 10
Finally, it is a shame to have the CT facility and not have 24-hour access to the CT service.1 In Hong Kong, radiologists are not immediately available during nonoffice hours. Nevertheless, 24-hour CT service is available because a technician is available to operate the CT machine. Physicians who provide frontline service to stroke patients should not take any compromise, such as TCCS. They should insist on 24-hour access to the CT service to provide appropriate treatment and improve the outcome for all stroke patients.
- Copyright © 1999 by American Heart Association
Mäurer M, Shambal S, Berg D, Woydt M, Hofmann E, Georgiadis D, Lindner A, Becker G. Differentiation between intracerebral hemorrhage and ischemic stroke by transcranial color-coded duplex-sonography. Stroke.. 1998;29:2563–2567.
Hacke W, Kaste M, Fieschi C, Toni D, Lesaffre E, Von KR, Boysen G, Bluhmki E, Hoxter G, Mahagne MH, Hennerici M. Intravenous thrombolysis with recombinant tissue plasminogen activator for acute hemispheric stroke: the European Cooperative Acute Stroke Study (ECASS). JAMA. 1995;274:1017–1025.
Hacke W, Kaste M, Fieschi C, Von KR, Davalos A, Meier D, Larrue V, Bluhmki E, Davis S, Donnan G, Schneider D, Diez TE, Trouillas P. Randomised double-blind placebo-controlled trial of thrombolytic therapy with intravenous alteplase in acute ischaemic stroke (ECASS II). Lancet. 1998;352:1245–1251.
Adams HP Jr, Brott TG, Furlan AJ, Gomez CR, Grotta J, Helgason CM, Kwiatkowski T, Lyden PD, Marler JR, Torner J, Feinberg W, Mayberg M, Thies W. Guidelines for thrombolytic therapy for acute stroke: a supplement to the guidelines for the management of patients with acute ischemic stroke. Stroke. 1996;27:1711–1718.
Lees KR, Haley EC, Warach S, Dyker AG. GV 150526: an overview of phase II studies in stroke patients. Stroke. 1999;30:265. Abstract.
IMAGES Trial Group. IMAGES: intravenous magnesium in acute stroke. Stroke. 1999;30:268. Abstract.
Fujii Y, Takeuchi S, Sasaki O, Minakawa T, Tanaka R. Multivariate analysis of predictors of hematoma enlargement in spontaneous intracerebral hemorrhage. Stroke. 1998;29:1160–1166.
Brott T, Broderick J, Kothari R, Barsan W, Tomsick T, Sauerbeck L, Spilker J, Duldner J, Khoury J. Early hemorrhage growth in patients with intracerebral hemorrhage. Stroke. 1997;28:1–5.
We thank Dr Cheung for his interest in our work. We agree with him that in most instances CT is unequivocally the method of choice in acute stroke because of its high sensitivity in the detection of intracerebral hemorrhages. Its ability to identify early signs of cerebral infarction is important when thrombolytic therapy is under considerationR1 R2 R3 and is surpassed only by MRI. Therefore, as outlined in our article, we recommend a CT or MRI examination whenever possible in the acute stage of stroke. However, large stroke trials like the International Stroke Trial or the Oxfordshire Community Stroke Project have shown that only two thirds of the patients actually received a CT scan before therapy was initiated.R4 R5 These European studies were conducted by centers experienced in stroke management that obviously had no 24-hour access to their CT facilities.
Stroke is a very common disorder, so the management of acute stroke usually lies with general hospitals. In Western Europe some of these hospitals do not have a 24-hour access to CT facilities. However, because of the widespread use of ultrasound in cardiology and gynecology, almost all general hospitals are equipped with a high-end color flow ultrasound system, and this equipment can be readily used for TCCS. In these institutions, physicians trained in TCCS would be able to identify intracerebral hemorrhages and occlusions of the major blood-supplying arteries of the brain. The high sensitivity of TCCS in detection of hematomas shown in our articleR6 is not explained by delayed ultrasound examination and consecutive enlargement of hematomas. We examined 66 patients before admission CT was performed, and it was previously shown also that hyperacute intracerebral hematomas could be accurately detected by TCCS.R7 In contrast, clinical examination was shown to have a low sensitivity in the differentiation between intracerebral hemorrhage and ischemic stroke.R8 Thus, the additional use of ultrasound performed by a trained and experienced sonographer would provide essential clues for further therapeutic and diagnostic considerations. This includes referral to a secondary care center with a neurosurgery department or a neurological intensive care unit. In addition, the ability to detect stroke complications and the real-time depiction of intracerebral hemodynamics makes ultrasound an important monitoring tool in acute stroke that would be desirable in all stroke units.
In our article we outlined the facts that TCCS is highly operator dependent and that intracerebral hemorrhages are not seen as easily with ultrasound as with CT. Also, small parietopolar and infratentorial bleedings may be missed in a significant number of patients, and approximately 15% of the patients have no suitable acoustic bone window. Thus, at present TCCS cannot be substituted for CT scan in stroke patients. It does, however, provide critical information in addition to the clinical judgment if CT is not readily available. Ongoing technical developments will substantially improve the quality and applicability of ultrasound systems as well as the diagnostic yield of TCCS.
Hacke W, Kaste M, Fieschi C, Toni D, Lesaffre E, Von KR, Boysen G, Bluhmki E, Hoxter G, Mahagne MH, Hennerici M. Intravenous thrombolysis with recombinant tissue plasminogen activator for acute hemispheric stroke: the European Cooperative Acute Stroke Study (ECASS). JAMA.. 1995;274:1017–1025.
The National Institute of Neurological Disorders and Stroke rtPA Stroke Study Group. Tissue plasminogen activator for acute ischemic stroke. N Engl J Med.. 1995;333:1581–1587.
Hacke W, Kaste M, Fieschi C, Von KR, Davalos A, Meier D, Larrue V, Bluhmki E, Davis S, Donnan G, Schneider D, Diez TE, Trouillas P. Randomized double-blind placebo-controlled trial of thrombolytic therapy with intravenous alteplase in acute ischemic stroke (ECASS II). Lancet.. 1998;352:124–1251.
Bamford J, Sandercock P, Dennis M, Burn J, Warlow C. A prospective study of acute cerebrovascular disease in the community: the Oxfordshire Community Stroke Project, 1981–86, 2: Incidence, case fatality rates and overall outcome at one year of cerebral infarction, primary intracerebral and subarachnoid haemorrhage. J Neurol Neurosurg Psychiatry.. 1990;53:16–22.
Mäurer M, Shambal S, Berg D, Woydt M, Hofmann E, Georgiadis D, Lindner A, Becker G. Differentiation between intracerebral hemorrhage and ischemic stroke by transcranial color-coded duplex sonography. Stroke.. 1998;29:2563–2567.