Practice Standards Practice Standards for Transcranial Doppler Ultrasound: Part I—Test Performance Andrei V. Alexandrov, MD, RVT Michael A. Sloan, MD Lawrence K.S. Wong, MD Colleen Douville, RVT Alexander Y. Razumovsky, PhD, RVT Walter J. Koroshetz, MD Manfred Kaps, MD Charles H. Tegeler, MD for the American Society of Neuroimaging Practice Guidelines Committee ABSTRACT Indications for the clinical use of transcranial Doppler (TCD) continue to expand while scanning protocols and quality of reporting vary between institutions. Based on literature anal- ysis and extensive personal experience, an international expert panel started the development of guidelines for TCD perfor- mance, interpretation, and competence. The first part de- scribes complete diagnostic spectral TCD examination for pa- tients with cerebrovascular diseases. Cranial temporal bone Received September 28, 2006, and in revised form September 28, 2006. Accepted for publication October 16, 2006. From the Barrow Neurological Institute, Phoenix, AZ (AVA); Carolinas Medical Center, Charlotte, NC (MAS); Chinese University of Hong Kong, Hong Kong, China (LKSW); Swedish Hospital, Seattle, WA (CD); Sentient Medical Systems, Inc., Cockeysville, MD (AYR); Harvard Medical School, Boston, MA (WK); University of Giessen, Giessen, Germany (MK); and Wake Forest University Medical Center, Winston-Salem, NC (CHT). Address correspondence to A. Alexandrov, MD, Barrow Neurological Institute, Suite 300 Neurology 500 West Thomas Rd, Phoenix, AZ 85013. E-mail: avalexandrov@ att.net windows are used for the detection of the middle cerebral ar- teries (MCA), anterior cerebral arteries (ACA), posterior cerebral arteries (PCA), C1 segment of the internal carotid arteries (ICA), and collateralization of flow via the anterior (AComA) and poste- rior (PComA) communicating arteries; orbital windows—for the ophthalmic artery (OA) and ICA siphon; the foraminal window— for the terminal vertebral (VA) and basilar (BA) arteries. Although there is a significant individual variability of the circle of Willis with and without disease, the complete diagnostic TCD exami- nation should include bilateral assessment of the M2 (arbitrarily located at 30-40 mm depth), M1 (40-65 mm) MCA [with M1 MCA mid-point at 50 mm (range 45-55 mm), average length 16 mm (range 5-24 mm), A1 ACA (60-75 mm), C1 ICA (60-70 mm), P1-P2 PCA (average depth 63 mm (range 55-75 mm), AComA (70-80 mm), PComA (58-65 mm), OA (40-50 mm), ICA siphons (55-65 mm), terminal VA (40-75 mm), proximal (75- 80), mid (80-90 mm), and distal (90-110 mm) BA]. The distal ICA on the neck (40-60 mm) can be located via submandibu- lar windows to calculate the VMCA/VICA index, or the Linde- gaard ratio for vasospasm grading after subarachnoid hemor- rhage. Performance goals of diagnostic TCD are to detect and optimize arterial segment-specific spectral waveforms, deter- mine flow direction, measure cerebral blood flow velocities and flow pulsatility in the above-mentioned arteries. These practice standards will assist laboratory accreditation processes by pro- viding a standard scanning protocol with transducer position- ing and orientation, depth selection and vessel identification for Copyright ◦ C 2007 by the American Society of Neuroimaging 11