Aims and objectives
Flow measurements in the cerebral aqueduct are helpful adjuncts to clinical and morphological criteria in differentiating communicating normal pressure hydrocephalus from non-communicating obstructive hydrocephalus due to aqueductal stenosis.
Quantification of cerebrospinal fluid (CSF) flow within the cerebral aqueduct can be quantified using phase contrast MRI (1,
2) utilizing the same principles as blood flow measurements in cardiac MR imaging.
Several parameters like peak flow velocity,
flow average or stroke volume can be determined.
So far,
this technique has not gained widespread acceptance mainly because of...
Methods and materials
A sagittal 3D T2 weighted T2w TSE sequence of the cranium was obtained for planning (Fig.
1).
The phase contrast sequence,
using cardiac triggering either via electrocardiogram or peripheral-pulse device,
is then set strictly perpendicular (transversal) over the aqueduct.
This sequence generates magnitude and phase images,
in our case an anatomical magnitude image (FFE/M),
a magnitude phase contrast image (PCA/M),
and the phase of the phase contrast image (PCA/P) (Fig.
2).
A processing software then calculates the flow parameters from the PCA/P image.
Cardiac triggering...
Results
The accuracy of a phase contrast MR measurement is adequate for the studied flow rates (0.1 – 0.5 ml/s),
with a maximal undervaluation of 5-10 % in higher flows (Fig.
5).
Slice thickness does not have a substantial influence on the measured flow parameters (Fig.
6).
In-plane resolution on the other hand has a substantial impact on the mean and peak flow velocity,
presumably due to partial volumes effects of larger flow with low velocity.
The selected VENC should be the same as or slightly...
Conclusion
CSF flow measurements have not been used extensively because reference values are highly dependent on MR hardware,
sequence parameters,
post-processing and patient population.
Our research quantified the degree of influence of various sequence parameters,
slice placement and ROI diameter on the obtained flow values.
In addition,
we showed that by keeping these variables constant reliable results can be obtained.
A limitation of our study is the non-pulsatile phantom model.
Pulsatile flow in patients may lead to larger deviations of flow parameters.
In addition,
acquisition time...
Personal information
Arash Najafi,
MD
Kantonsspital Winterthur
Winterthur,
Switzerland
Tel.: +41522664117
References
1.
Lee,
Jeong Hyun,
Ho Kyu Lee,
Jae Kyun Kim,
Hyun Jeong Kim,
Ji Kang Park,
and Choong Gon Choi.
2004.
“CSF Flow Quantification of the Cerebral Aqueduct in Normal Volunteers Using Phase Contrast Cine MR Imaging.” Korean Journal of Radiology 5 (2): 81–86.
doi:10.3348/kjr.2004.5.2.81
2.Battal,
B,
M Kocaoglu,
N Bulakbasi,
G Husmen,
H Tuba Sanal,
and C Tayfun.
2011.
“Cerebrospinal Fluid Flow Imaging by Using Phase-Contrast MR Technique.” The British Journal of Radiology 84 (1004): 758–65.
doi:10.1259/bjr/66206791.
3.Luetmer,
Patrick H.,
John Huston,
Jonathan A....