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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3644_Библиотеки_им_академика_М_И_Перельмана
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1Embryological and Anatomical Introduction10
Fig. 1.10E–H (continued). The posterior part of the pons looks mature,displaying E
a high signal intensity on TlWI and F low signal intensity on T2WI. The internal capsules do not yet show any process of myelination, since they demonstrate G low signal
intensity on T1WI and H high signal intensity on T2WI. The white matter appears as
lower signal intensity on T2WI than on prenatal study (probably because the sequence used is different).(Courtesy of N. Girard)
11Preliminary Remarks
Fig. 1.12A,B. Axial T1-weighted images (T1WI) in a 35-week-old fetus. The ventricles are almost invisible, as are the subarachnoid spaces. The cortical ribbon is not
well delineated from the subarachnoid spaces and the white matter on T1WI. B The
optic radiations display a high signal intensity (clearly seen on the left side). A The
central area also has high signal intensity.These features correspond to the developing process of myelination,since the so-called myelination gliosis has high signal intensity on T1WI. (Courtesy of N. Girard)
Fig. 1.11. A Axial T1-weighted image (T1WI) in a 31-week-old fetus. B Axial T2-
weighted image (T2WI) in a 32-week-old fetus. High signal intensity can be seen on
T1WI in the posterior limb of the right internal capsule, corresponding to the myelination process.A The hemispheric parenchyma appears homogeneous on T1WI.B It
is easily recognizable on T2WI as high signal intensity. Note that the pons demonstrates low signal intensity on T2WI secondary to maturation.(Courtesy of N. Girard)
1Embryological and Anatomical Introduction12
Fig. 1.13. A–C Legend see p. 13
13Preliminary Remarks
Fig. 1.14. A Coronal T1-weighted image (T1WI) and B axial
T2-weighted image (T2WI) in
a 1-month-old child.A The optic radiations are not yet myelinated,since they show myelination gliosis only on T1WI as
high signal intensity.B They appear as high signal intensity on
T2WI. (Courtesy of N.Girard)
Fig. 1.13. A–C Axial T1-weighted images (T1WI), D–F axial T2-weighted images
(T2WI) and G–I axial proton density-weighted images (PDWI) in a 3-week-old newborn. The posterior part of the pons shows high signal intensity on C T1WI and low
signal intensity on F T2WI and (I) PDWI, corresponding to the complete maturation
of the sensory pathways of the pons. The central area appears as high signal intensity
on A T1WI and as low signal intensity on D T2WI and G PDWI; this results from the
complete maturation of the central area.B,E,H This feature is also observed in the occipital area. On the other hand, at this stage the internal capsules only show myelination gliosis on B T1WI as high signal intensity, since it appears as high signal intensity on E T2WI and H PDWI. The internal capsules are difficult to delineate on T1WI
only,since the basal ganglia also display high signal intensity on T1WI. The immature
white matter shows low signal intensity on A–C T1WI and high signal intensity on
D–F T2WI and G–I PDWI. Note also that the basal ganglia demonstrate high signal
intensity on B T1WI and low signal intensity on D T2WI and H PDWI. (Courtesy of N.
Girard)
▲
1Embryological and Anatomical Introduction14
Fig. 1.15. A Axial T2-weighted image (T2WI), B proton density-weighted image
(PDWI), and c axial T1-weighted image (T1WI) in a 2.5-month-old child. (The child
in C is a different one from the one in A, B.) Myelination begins in the posterior limb
of the internal capsules as low signal intensity on A T2WI and B PDWI. The optic radiations are not myelinated, since they show high signal intensity on both A T2WI
and C T1WI.The immature white matter still appears as low signal intensity on T1WI
and as high signal intensity on T2WI. (Courtesy of N.Girard)
Fig. 1.16. A–C Axial T2-weighted images (T2WI), D lateral T1-weighted image
(T1WI), and E sagittal T1WI in a 4-month-old child.High signal intensity is observed
on T1WI in the semioval center,the central area, the internal capsule,and the optic radiations.The deep white matter displays a similar signal as the cortex on T1WI and no
longer has the low signal intensity seen in neonates.A On T2WI, myelination begins
in the semioval center. B, C The internal capsules are entirely myelinated, as are the
optic radiations, since they show low signal intensity on T2WI.On the other hand,the
deep white matter is still unmyelinated on T2WI.D, E see p. 15
15Preliminary Remarks
Fig. 1.16 (continued). E The corpus callosum shows high signal intensity on TlWl.
C However,myelination is not complete on T2WI.(Courtesy of N.Girard)
Fig. 1.17A–C. Axial T2-weighted images (T2WI) in an 8-month-old child.A Myelina-
tion is complete in the semioval center. B It is also complete in the corpus callosum.
C The optic radiations show complete myelination in their lower portion. The upper
part is not fully myelinated. Note at this stage that the hemispheric parenchyma appears homogeneous, but the subcortical white matter fibers are not yet myelinated.
(Courtesy of N. Girard)
1Embryological and Anatomical Introduction16
Fig. 1.18. A–C Axial T1-weighted images (T1WI) and D–F axial T2-weighted images
(T2WI) in a 19-month-old child. The pattern is similar to that found in adults. The
deep white matter,including the subcortical fiber tracts, appears as high signal intensity on T1WI and as low signal intensity on T2WI.(Courtesy of N. Girard)
17Preliminary Remarks
Fig. 1.19. Relationships of the subpial space. (From Weller 1994)
1Embryological and Anatomical Introduction18
Fig. 1.20. The subpial space (sps) of the human cerebral
cortex. The pia mater is at the top,and an artery surround-
ed by two or three layers of smooth muscle cells is seen in
the center.A thin layer of pial cells (PC) surrounds the
artery, enclosing its perivascular space. The subpial space
separates the artery from the glia limitans (gl). Transmis-
sion electron micrograph (TEM), ¥5,000. (Reproduced
from Zhang et al.1990, with permission)
Fig. 1.21. The subpial space (higher magnification than
Fig. 1.20). The pia mater is at the top,and the glia limitans
at the bottom. Within the subpial space is a thin-walled
vein filled with erythrocytes. Collagen bundles (coll) are
distributed through the subpial space and dissociated leptomeningeal cells are also seen. A thin basement membrane coats the astrocyte processes of the glia limitans.
Tr ansmission electron micrograph (TEM), ¥6,700.(Repro-
duced from Alcolado et al.1988, with permission)
19Preliminary Remarks
FFig. 1.22. Collagen bundles
within the spinal subpial space.
Scanning electron micrograph
(SEM), ¥1,000
Fig. 1.23A,B. The subpial space (sps) in inflammation. A The subarachnoid space
(top) is filled with macrophages and dead polymorphonuclear leukocytes. Three vessels in the subarachnoid space have expanded perivascular spaces surrounded by
black-stained reticulin fibers. In the center,the subpial space is expanded by inflam-
matory cells.Surface of the cerebral cortex (bottom).B Inflammatory cells fill the sub-
pial space, separating the pia mater (p) from the glia limitans (gl). An artery is seen
entering the cerebral cortex. Light microscopy, reticulin stain, ¥470. (Reproduced
with permission from Hutchings and Weller 1986)
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