The Substantia Nigra in Parkinson Disease: Proton Density-Weighted Spin-Echo and Fast Short Inversion Time Inversion-Recovery MR Findings
Hirobumi Oikawa*,
Makoto Sasaki*,
,
Yoshiharu Tamakawa*,
Shigeru Ehara* and
Koujiro Tohyama
* Department of Radiology, Iwate Medical University, Uchimaru, Morioka, Japan
High Field Magnetic Resonance Imaging Research Institute, Iwate Medical University, Uchimaru, Morioka, Japan
Department of Neuroanatomy, Iwate Medical University, Uchimaru, Morioka, Japan
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FIG 1. Schematic drawing of the three-dimensional anatomy of the SN from the left superoposterolateral aspect. The SN is located mainly beneath the red nucleus.
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FIG 2. Axial MR images through the upper midbrain.
A, Axial T2-weighted image in a healthy control subject, a 55-year-old woman. A hypointense area, believed to be SNr, is located in the anteromedial part of the crus cerebri (arrow). No hyperintense gray matter area, representing the SN, is visible.
B, Proton density-weighted image in the same section as in A. The SN (n) is clearly identified as an area of hyperintense gray matter surrounded by the hypointense red nucleus (r) and the crural fibers (c).
C, T1-weighted image in the same section as in A. The SN is not evident.
D, Fast STIR image in the same section as in A. The SN (n) is readily identified as a structure with gray matter signal intensity. The red nucleus (r) with surrounding white matter and the crural fibers (c) are identified as areas with relatively low signal intensity.
E, Video-reversed fast STIR image onto which the hypointense areas on a T2-weighted image are superimposed (shaded areas). The hypointense area on the T2-weighted image includes the crural fibers and the anterior part of the SN.
F, Corresponding axial-section specimen obtained from a human cadaver.
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FIG 3. Axial MR images through the lower midbrain.
A, Axial T2-weighted image in the same control subject as in Figure 2. A hypointense area is visible on only the anteromedial end of the crus cerebri (arrow). An area with relatively high signal intensity suggestive of the SN is not depicted.
B, Proton density-weighted image in the same section as in A. The SN (n) is clearly depicted as a structure with hyperintense gray matter between the crural fibers (c) and the medial lemniscus (m).
C, T1-weighted image obtained at the same section as in A. The SN is not visible.
D, Fast STIR image in the same section as in A. The SN (n) is identified as an area of hyperintense gray matter posterior to the crural fibers (c). The medial lemniscus (m) and the decussation of superior cerebellar peduncle (d) show relatively low signal intensity.
E, Video-reversed fast STIR image onto which the hypointense areas on a T2-weighted image are superimposed (shaded areas). The hypointense areas on the T2-weighted image are located on the anteromedial part of the peduncular fibers, but they barely include the SN.
F, Axial-section specimen obtained in a human cadaver through the lower end of the midbrain. The SN (n) is not present on this section. It is located between the crural fibers cerebri (c) and medial lemniscus (m).
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FIG 4. Coronal MR images through the red nucleus.
A, T2-weighted image from a control subject, a 58-year-old woman. The red nucleus is depicted as a round hypointense structure. Another hypointense area is lateral to the red nucleus (arrow).
B, Proton density-weighted image in the same section as in A. The SN (n) is depicted as an area of hyperintense gray matter inferolateral to the red nucleus (r).
C, T1-weighted image obtained in the same section as in A. The SN is not visible.
D, Coronal fast STIR image obtained in the same section as in A. The SN (n) is readily identified as an area of hyperintense gray matter. The red nucleus (r) is also depicted.
E, Video-reversed fast STIR image onto which the hypointense regions on a T2-weighted image are superimposed (shaded areas). The hypointense areas on the T2-weighted image are located on only the superolateral end of the SN.
F, Gross specimen of the human brain. The SN (n) is identified as a tilted bandlike area inferolateral to the red nucleus (r). The SN is present through the entire length of the midbrain, and its lower half is located beneath the red nucleus.
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FIG 5. Sagittal MR images through the red nucleus.
A, Sagittal T2-weighted image obtained in a control subject, a 55-year-old woman. Hypointense areas are visible at the red nucleus and at the anterior margin of the midbrain (arrow). The boundary of the hyperintense band is unclear at the level of lower midbrain.
B, Proton density-weighted image in the same section as in A. The SN is identified as a tilted gray matter structure (n) anteroinferior to the red nucleus (r).
C, T1-weighted image in the same section as in A. The SN is not identified.
D, Fast STIR image at the same section. The SN is identified as a bandlike structure with gray matter signal intensity (n) that is mainly located anteroinferior to the red nucleus (r).
E, Video-reversed fast STIR image onto which the hypointense regions of a T2-weighted image are superimposed (shaded areas). The low-signal-intensity area on the T2-weighted image includes the crural fibers and only the anterosuperior end of the SN.
F, Sagittal gross specimen of the human brain slightly lateral to the MR images. The SN (n) is identified as a tilted band-shaped area.
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FIG 6. Oblique coronal MR images.
A, Oblique coronal T2-weighted image obtained through the level of the posterior commissure from a control subject, 58-year-old woman. Hypointense areas are visible at the red nucleus (r) and in the area including the medial half of the crural fibers and the anterior part of the SN (arrow). An area of hyperintense gray matter suggestive of the SN is not shown.
B, Oblique coronal fast STIR MR images obtained at the same section as in A. The SN (n), crural fibers (c), and red nucleus (r) with surrounding white matter are readily identified. Almost the entire margin of the SN is clearly identified. The outline indicates the measured area.
C, Corresponding oblique coronal section of the human specimen. The SN (n) is identified as a crescent gray matter structure located posterior to the crural fibers (c) and anterolateral to the red nucleus (r).
D, Oblique coronal T2-weighted image through the level of the superior colliculus obtained in the same subject as in A. The hypointense area is depicted at only the anteromedial aspect of the crus cerebri (arrow). A hyperintense area suggestive of the SN is not identified.
E, Oblique coronal fast STIR image obtained at the same section as in D. A bandlike structure with hyperintense gray matter that represents the SN (n) is depicted posteromedial to the hypointense crural fibers (c). The outline indicates the measured area.
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FIG 7. Schematic drawings of the multiplanar localization of the area of hyperintense gray matter on proton density-weighted and fast STIR images and of the hypointense area on the T2-weighted images (shaded area). The hypointense area on the T2-weighted image includes the crural fibers and only the anterosuperior potion of the SN. The dotted line indicates the presumable boundary between the SNr and the SNc.
A, Axial plane through the upper and lower midbrain.
B, Sagittal plane.
C, Coronal plane.
D, Oblique coronal plane.
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FIG 8. On fast STIR images, volume loss in the SN was not evident in patients with Parkinson disease. On T2-weighted images, thinning of the relatively hyperintense structure (arrow in C) was not evident in patients with Parkinson disease.
A–C, Images in a patient with Parkinson disease, a 52-year-old woman. Oblique coronal fast STIR images through the level of the posterior commissure (A) and superior colliculus (B) and axial T2-weighted image (C).
D–F, Corresponding images in a control subject, a 55-year-old woman.
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FIG 9. Area of the SN in Parkinson disease .
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