scholarly journals Letter in response to: “Pulmonary thrombi are not detected by 3D magnetic resonance angiography in adults with sickle cell anemia and an elevated triscuspid regurgitant jet velocity”

2009 ◽  
pp. NA-NA
Author(s):  
Eduard J. Van Beers ◽  
Bart J. Biemond ◽  
John-John B. Schnog ◽  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Sickle Cell ◽  
Sickle Cell Anemia

Change over Time of Transcranial Doppler Cerebral Blood Flow Velocity and the Relationship with Turbulence on Magnetic Resonance Angiography in Patients with Sickle Cell Anemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3799-3799
Author(s):  
Krishna Kotecha ◽  
Mara Prengler ◽  
Dawn E. Saunders ◽  
Deborah K.M. Hewes ◽  
Fenella J. Kirkham ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Transcranial Doppler ◽  
Maximum Velocity ◽  
Additional Tool ◽  
The Relationship ◽  
Over Time ◽  
Time Point

Abstract Cerebrovascular disease (CVD) involving the circle of Willis and documented using time-averaged maximum velocity (TAMM) on transcranial Doppler (TCD) and on magnetic resonance angiography (MRA), is common in sickle cell anemia (SCA). Few studies have examined the natural history of CVD. The relationship between TAMM and MRA turbulence is also unclear. We aimed to examine time trends in TAMM and any relationship with clinical stroke and silent infarction (SI) on MRI. We also wanted to determine (a) the degree of MRA turbulence associated with TCD V>200 cm/sec (b) the TCD signature of MRA occlusion and (c) the proportion of patients with no TCD signal who did not have MRA occlusion. TCD was performed in a cohort of 169 patients with highest TAMM measured in either internal carotid/middle cerebral artery recorded (time point 1). Studies were categorised as follows: 0=normal TAMM, 1=170–200cm/sec (conditional TAMM), 2=>200cm/sec, 3=<50cm/sec. The median age was 8 (range 1–25) years. Six (4%) patients had an abnormal scan with TAMM>200cm/sec; 3 had not been screened for SCD neonatally. 11 (7%) patients had abnormally low TAMM <50cm/sec. In the neonatally screened cohort, the median for the highest TAMM ever recorded was 124 (range 33–258 cm/s) at a median age of 9 (1–25 years). 91 patients had repeat TCD at time point 2 (median 5 years later). 63 patients remained normal throughout and 16 with initially normal TAMM changed to TAMM<50cm/s at time point 2. 3/5 patients with TAMM>200cm/s at time point 1 had TAMM<50cm/s at time point 2 and 3/5 patients with TAMM<50cm/s at time point 1 remained low at time point 2. Patients with abnormally high or low TAMM at time point 1 were more likely to have abnormally low TAMM at time point 2 (x2, p= 0.001). Although clinical stroke (x2, p=0.001)and SI were commoner in those with abnormal TCD, the latter relationship was not significant (x2, p=0.94). 92 patients had both TCD and MRA within 1 month. The results were analysed for symptomatic (n=63) and asymptomatic (n=29) groups. There was no difference between groups for age (median 13; range 0–27 years). MRAs were examined for evidence of MCA turbulence graded as none, mild, moderate, severe or occlusion. There was a significant association between TAMM and MRA turbulence for the whole (ANOVA, right p=0.0001, left p=0.001), and symptomatic groups (ANOVA, right p=0.01, left p=0.025). All patients with TAMM>200 cm/sec had severe MCA turbulence but 2/3 with TAMM>170<200 cm/sec had normal MRA. The highest TAMM seen in a patient with occlusion was 80 cm/sec. Eighteen patients had no TCD signal, of whom 11 had abnormal MRA (3 occlusion). There is progressive CVD in children with SCD over time as evidenced by an increase in the number of children with abnormally low TCD. Patients with low TAMM or no signal may require MRA to document the severity of their CVD. Patients with TAMM>80 cm/sec are unlikely to have occlusion. As silent infarction is not predicted by TCD, MRA has a role as an additional tool to identify high risk patients, particularly in those with low TAMM. TAMM>200cm/sec appears to be a screen for severe turbulence, although this condition may represent specific pathophysiology rather than part of a spectrum.

Diagnosis of cerebrovascular disease in sickle cell anemia by magnetic resonance angiography

1990 ◽  
Vol 117 (4) ◽  
pp. 551-555 ◽  
Author(s):  
Max Wiznitzer ◽  
Paul M. Ruggieri ◽  
Thomas J. Masaryk ◽  
Jeffrey S. Ross ◽  
Michael T. Modic ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Cerebrovascular Disease ◽  
Sickle Cell ◽  
Sickle Cell Anemia

Correlation Between Cerebral Blood Flow Velocities Measured By Magnetic Resonance and Transcranial Doppler Ultrasound in Children with Sickle Cell Anemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2496-2496
Author(s):  
Monica L. Hulbert ◽  
Dustin K. Ragan ◽  
Hongyu An ◽  
Cihat Eldeniz ◽  
Geetika Khanna ◽  
...  
Keyword(s):  
Blood Flow ◽  
Magnetic Resonance ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Transcranial Doppler ◽  
Arterial Stenosis ◽  
Acquisition Time ◽  
Transfusion Therapy ◽  
Blood Flow Velocities ◽  
Flow Velocities

Abstract Background Transcranial Doppler (TCD) ultrasonography is the standard stroke screening test for children with sickle cell anemia (SCA). However, approximately 10% of children have inadequate ultrasonographic windows for a successful TCD study, and some clinical sites may lack the equipment or personnel to perform TCDs in children. Magnetic resonance imaging (MRI) techniques can also measure blood flow velocities and could substitute for TCD in these clinical scenarios. We tested the hypothesis that MRI-derived middle cerebral artery (MCA) blood flow velocities would correlate with TCD-derived MCA blood flow velocities in children with SCA. Methods Children age 6 years and up with SCA at their baseline state of health underwent TCD and MRI as part of a prospective clinical study. Imaging TCD of the bilateral MCAs to determine time-average mean of maximum blood flow velocities (TCD-CBFV) were performed using clinical ultrasound equipment. MRIs were performed at 3T without sedation. MRI cerebral time-averaged mean blood flow velocities (MR-CBFV) were measured in the MCAs using phase contrast sequences without cardiac cycle gating to shorten acquisition time and reduce ghosting artifacts. TCD- and MR-CBFV of each hemisphere were compared. Silent cerebral infarctions (SCIs) were categorized as present or absent in each hemisphere. Non-parametric tests were used with a level of significance of <0.05. Statistics were performed in SPSS version 21. Results Twenty hemispheres from 15 children had both TCD-CBFV and MR-CBFV measurements. Median age was 9 years (IQR 6.25-10). In these children, two hemispheres had unobtainable TCDs due to skull thickness, and eight hemispheres had MR-CBFV excluded due to patient motion or poor positioning. The median TCD-CBFV was 116 cm/sec (IQR 90.25-124) and none of the included hemispheres had arterial stenosis or TCD-CBFV in the conditional or abnormal range. Eight included hemispheres were from children receiving chronic blood transfusion therapy for primary or secondary stroke prevention. There was a linear relationship between TCD-CBFV and MR-CBFV (Spearman correlation, ρ=0.781, p<0.001, Figure) although MR-CBFV values were lower than TCD-CBFV values (median difference 32.6%, IQR 26.7-42.8). When evaluating only the children not receiving chronic transfusion therapy, MR-CBFV was significantly higher in 8 hemispheres without SCIs (median 80 cm/sec, IQR 77.8-87.8) than in 4 hemispheres with SCIs (median 60 cm/sec, IQR 44.6-72.3, p=0.004). In a multivariate model adjusting for age, MR-CBFV continued to be associated with presence of SCIs (p=0.036). There was no significant difference in TCD-CBFV when analyzed by SCI status (p=0.2), consistent with published studies of TCD-CBFV and SCIs. Conclusions In this small cohort of children with SCA, MR-CBFV correlated significantly with TCD-CBFV, but MR-CBFV values were approximately 30% lower than TCD-CBFV. This may be due to the method of acquiring MR-CBFV via non-gated methodology, which is known to produce lower blood flow velocity estimates. Further work is needed to determine a threshold for high-risk MR-CBFV values before this modality could be used as a substitute for TCD screening. Lower MR-CBFV was associated with SCIs, suggesting a potential role for MR-CBFV in predicting SCI risk. The relationship between MR-CBFV and SCIs should be explored further. Disclosures Hulbert: Pfizer, Inc.: Other: spouse employment. Fields:NeuroPhage Pharmaceuticals: Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

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