Article Figures & Data
Figures
- FIG 1.
T1-weighted MR imaging and overlaid Jacobian maps of estimated changes between pre- and postshunt imaging for a representative patient, a 66-year-old man with iNPH. Sagittal, coronal, and axial slices of pre- (A) and postshunt (B) T1WI after registration to the patient’s common mean and differential bias correction. C, Map of voxelwise Jacobian determinants overlaid on the preshunt T1WI to demonstrate changes that occurred after shunt placement by warping the late-to-early image: The ventricles contracted (blue) and CSF spaces at the vertex and surrounding parenchyma expanded (red and orange). Although changes in parenchymal volume are not visibly apparent on the T1WI, the coronal images demonstrate decreased crowding of the sulci at the vertex after shunt placement (orange arrows), corresponding to regions that showed an increase in cortical volume after shunt placement. The callosal angle measurement is demonstrated in the coronal image in row A (white lines).
- FIG 2.
Voxelwise maps of estimated mean percentage change in volume from pre- to postshunt MR imaging across all patients. Axial, coronal, and sagittal slices of the mean estimated percentage change in volume (log-Jacobian, which is centered at zero) for all voxels within the total intracranial volume mask. In this display, the tissue class (CSF, gray matter, white matter) is not considered. After shunt placement, there was an expansion or increase in CSF and parenchymal volumes primarily near midline at the vertex (red). Contraction or decrease in volume occurred in the ventricles, extraventricular CSF spaces such as the Sylvian fissures, and anterior-inferior frontal and temporal convexities (blue).
- FIG 3.
Percentage volume change by patient after shunt placement. Percent change in ventricular (A) and mean cortical (B) volume across all ROIs versus time. Each patient is represented by a separate line; patients with 1 postshunt MR imaging are represented by a solid line, and patients with 2 postshunt MRIs are represented by a dotted line. Time zero is the date of shunt placement. In general, ventricular volumes decreased and mean cortical volume increased after shunt placement. In the patients with 2 postshunt MRIs, there was a continued decrease in ventricular volume from postshunt MR1 to MR2 and a small variable change in cortical volume during that interval.
- FIG 4.
Regional cortical mean percentage volume change. Surface-renderings of mean percentage change in cortical volume among all participants by cortical region in the ADIR122 atlas. These data are a subset of the data shown in Fig 2, considering only voxels determined to be cortical gray matter and demonstrating ROI-wise results, the main analytic method used in this work. Red indicates an increase in volume or expansion from pre- to postshunt MR imaging examinations and is primarily present at the midline vertex regions. Blue indicates a decrease in volume or contraction and is seen adjacent to the temporal horns and Sylvian fissures as well as related to Codman Certas Plus valve artifacts (right occipital). The first column shows right-hemisphere lateral and medial views. The second column shows left-hemisphere lateral and medial views. The third column shows top and bottom views.
