Additionally, T1 hyperintense thrombus can mimic normal flow and enhancement patterns, which necessitates evaluation with noncontrast MRI imaging. Volumetric MRI sequences are essential for contrast-enhanced MRV. Delayed postcontrast imaging can further increase the sensitivity for detection of T1 isointense thrombus. MRV Head Without IV Contrast Although contrast-enhanced venography is the most accurate means of assessment for CVT [104], TOF and phase- contrast MRV are noncontrast alternatives for the diagnosis of CVT. If the findings on noncontrast MRV are unclear, then further imaging with contrast-enhanced CTV or MRV should be considered. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid Doppler in the setting of CVT. However, US assessment of the adjacent venous structures could yield useful information about the extent of the thrombus if extending into the neck. US Duplex Doppler Transcranial There is no relevant literature to support the use of transcranial Doppler in the setting of CVT. Variant 9: Adult. Asymptomatic cervical bruit. Initial imaging. Cervical carotid bruit is an important diagnostic sign of potential underlying carotid stenosis because patients with carotid bruit are >50% more likely to harbor hemodynamically significant internal carotid stenosis. Although the advent of electronic auscultation has driven the negative predictive value to an all-time high, the positive predictive value is now at an all-time low, in the 30% range, which increases the importance of radiographic evaluation following detection of carotid bruit [107]. In the patient with recent TIA or minor stroke who is a candidate for CEA or stenting, the presence or absence of carotid bruit does not alter the necessity or urgency of evaluating the degree of carotid stenosis (see Variants 1-5).
Cerebrovascular Diseases Stroke and Stroke Related Conditions PCAs. Additionally, T1 hyperintense thrombus can mimic normal flow and enhancement patterns, which necessitates evaluation with noncontrast MRI imaging. Volumetric MRI sequences are essential for contrast-enhanced MRV. Delayed postcontrast imaging can further increase the sensitivity for detection of T1 isointense thrombus. MRV Head Without IV Contrast Although contrast-enhanced venography is the most accurate means of assessment for CVT [104], TOF and phase- contrast MRV are noncontrast alternatives for the diagnosis of CVT. If the findings on noncontrast MRV are unclear, then further imaging with contrast-enhanced CTV or MRV should be considered. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid Doppler in the setting of CVT. However, US assessment of the adjacent venous structures could yield useful information about the extent of the thrombus if extending into the neck. US Duplex Doppler Transcranial There is no relevant literature to support the use of transcranial Doppler in the setting of CVT. Variant 9: Adult. Asymptomatic cervical bruit. Initial imaging. Cervical carotid bruit is an important diagnostic sign of potential underlying carotid stenosis because patients with carotid bruit are >50% more likely to harbor hemodynamically significant internal carotid stenosis. Although the advent of electronic auscultation has driven the negative predictive value to an all-time high, the positive predictive value is now at an all-time low, in the 30% range, which increases the importance of radiographic evaluation following detection of carotid bruit [107]. In the patient with recent TIA or minor stroke who is a candidate for CEA or stenting, the presence or absence of carotid bruit does not alter the necessity or urgency of evaluating the degree of carotid stenosis (see Variants 1-5).