Postmortem NmMRI and histological correlations in the SNc
Case 1 (normal control)
Fig. 2: Case 1 (normal control)
A. NmMRI of the midbrain shows diffuse hyperintense areas in the SNc. The signal intensity of the SNc is higher than that of the SC. The signal intensity of the red nucleus, medial lemniscus, and cerebral peduncle is lower than that of the SC.
B. A myelin-stained (Klüver-Barrera stain) section corresponding to (A) shows that staining of the SNc is the same as that of the SC. Strong myelin staining is seen in the red nucleus, medial lemniscus, and cerebral peduncle.
C. Ferritin immunohistochemistry corresponding to (A) shows that ferritin deposition in the SNc is milder than that in the red nucleus, medial lemniscus, and cerebral peduncle.
D. NmMRI of the SNc (boxed area in A) shows diffuse hyperintensity in the SNc. Multiple hypointense spots are seen in the medial side of the SNc.
E. A myelin-stained (Klüver-Barrera stain) section corresponding to the boxed area in (B).
F. Histological finding of the boxed area in (E) shows well-preserved neuromelanin-containing neurons (dotted lines). Bundles of myelinated nerve fibers (black arrows) and dilated perivascular spaces (white arrows) are seen in the SNc.
Postmortem NmMRI of the midbrain showed a diffuse hyperintense areas in the SNc.
The signal intensity of the SNc was higher than that of the SC (Fig.
2A).
Myelin staining of the SNc was the same as that of the SC,
whereas strong myelin staining was seen in the red nucleus,
medial lemniscus,
and cerebral peduncle (Fig.
2B).
Diffuse ferritin deposition in the SNc was fainter than that in the red nucleus,
medial lemniscus,
and cerebral peduncle (Fig.
2C).
Histologically,
the diffuse hyperintense area in the SNc reflected well-preserved neuromelanin-containing neurons,
whereas the hyperintense area with multiple hypointense spots in the SNc reflected neuromelanin-containing neurons with bundles of myelinated nerve fibers and dilated perivascular spaces (Fig.
2D-F).
Case 2 (DLB)
Fig. 3: Case 2 (DLB case)
A. NmMRI of the midbrain shows no apparent hyperintense area in the SNc. The signal intensity in the SNc is the same as that of the SC. Mild hyperintensity in the left lateral part of the SNc is seen.
B. A myelin-stained (Klüver-Barrera stain) section corresponding to (A) shows that staining of the SNc is the same as that of the SC. Strong myelin staining is seen in the red nucleus, medial lemniscus, and cerebral peduncle.
C. Ferritin immunohistochemistry corresponding to (A) shows that ferritin deposition in the SNc is milder than that in the red nucleus, medial lemniscus, and cerebral peduncle.
D. NmMRI of the SNc (boxed area in A) shows mild hyperintensity in the lateral part of the SNc.
E. A myelin-stained (Klüver-Barrera stain) section corresponding to the boxed area in (B).
F. Histological finding of the boxed area in (E) shows severe loss of neuromelanin-containing neurons. Fine bundles of myelinated nerve fibers (black arrows) and dilated perivascular spaces (white arrows) are seen in the SNc.
NmMRI of the midbrain showed that the signal intensity of the SNc was the same as that of the SC.
Mild hyperintensity in the left lateral part of the SNc was seen (Fig.
3A).
Myelin staining of the SNc was the same as that of the SC,
whereas strong myelin staining was seen in the red nucleus,
medial lemniscus,
and cerebral peduncle (Fig.
3B).
Diffuse ferritin deposition in the SNc was milder than that in the red nucleus,
medial lemniscus,
and cerebral peduncle (Fig.
3C).
Histologically,
the signal intensity of the SNc was the same as the intensity of the SC,
reflecting severe loss of neuromelanin-containing neurons,
fine bundles of myelinated nerve fibers,
and dilated perivascular spaces (Fig.
3D-F).
Case 3 (PD)
Fig. 4: Case 3 (PD case)
A. NmMRI of the midbrain shows no apparent hyperintense area in the SNc. The signal intensity of the SNc is the same as that of the SC. Non-homogenous hyperintensity due to artifact is seen in the right lateral part of the SNc.
B. A myelin-stained (Klüver-Barrera stain) section corresponding to (A) shows that staining of the SNc is the same as that of the SC. Strong myelin staining is seen in the red nucleus, medial lemniscus, and cerebral peduncle.
C. Ferritin immunohistochemistry corresponding to (A) shows that ferritin deposition in the SNc is milder than that in the red nucleus, medial lemniscus, and cerebral peduncle.
D. NmMRI of the SNc (boxed area in A) shows no apparent hyperintense area in the SNc.
E. A myelin-stained (Klüver-Barrera stain) section corresponding to the boxed area in (B).
F. Histological finding of the boxed area in (E) shows severe loss of neuromelanin-containing neurons. Dilated perivascular spaces (white arrows) are seen in the SNc.
NmMRI of the midbrain showed that the signal intensity in the SNc was the same as that of the SC (Fig.
4A).
Myelin staining of the SNc was the same as that of the SC,
whereas strong myelin staining was seen in the red nucleus,
medial lemniscus,
and cerebral peduncle (Fig.
4B).
Diffuse ferritin deposition in the SNc was milder than that in the red nucleus,
medial lemniscus,
and cerebral peduncle (Fig.
4C).
Histologically,
the signal intensity of the SNc was the same as the intensity of the SC,
reflecting severe loss of neuromelanin-containing neurons,
fine bundles of myelinated nerve fibers,
and dilated perivascular spaces (Fig.
4D-F).
Evaluation of signal intensity and the number of neuromelanin-containing neurons in the SNc
The contrast ratios and the number of neuromelanin-containing neurons in the four parts of the SNc in each case,
for a total of 12 parts of the SNc,
are shown in Table 1.
Table 1: The contrast ratio and the number of neuromelanin-containing neurons in each area of the SNc. SNc: substantia nigra pars compacta; DLB: dementia with Lewy bodies; PD: Parkinson's disease.
Both contrast ratios of the SNc and the number of neuromelanin-containing neurons were higher in the normal control case (case 1) than in the DLB case (case 2) and PD case (case 3).
There were statistically significant differences in the contrast ratios of the SNc between the control and PD case (P < 0.05).
No statistically significant difference was observed between any other combinations (Fig.
5).
Fig. 5: Boxplot of the contrast ratios of the SNc in the normal control, DLB, and PD cases. A statistically significant difference between the control and PD cases (P < 0.05) is observed (Kruskal-Wallis test with Tukey post-hoc analysis). The box ends represent the first and third quartiles. The end points of each graph represent the smallest and largest values.
There was a significant positive correlation between signal intensity and the number of neuromelanin-containing neurons in the 12 parts of the SNc ({x: the number of neuromelanin-containing neurons,
y: the contrast ratios of the signal intensity},
y = 0.000264x + 0.0307,
r2 = 0.378,
P < 0.05) (Fig.
6).
Fig. 6: Scatter chart of the contrast ratios of the SNc determined by NmMRI and the number of neuromelanin-containing neurons in 12 parts of the SNc ({x: the number of neuromelanin-containing neurons, y: the contrast ratios of SNc}, y = 0.000264x + 0.0307, r2 = 0.378, P < 0.05).