Key points of diagnosis and MRI signs of progressive supranuclear palsy

Progressive supranuclear palsy (PSP), also known as Steele-Rchardson-Olszewski syndrome, is a rare degenerative disease of the central nervous system characterized by pseudobulbar palsy, vertical supranuclear ophthalmoplegia, extrapyramidal muscle stiffness, gait ataxia, and mild dementia
.
The clinical manifestations of PSP are highly variable, and there are no specific laboratory tests, which are easily misdiagnosed
.
MRI is very important in the diagnosis of this disease, and we will study the MRI signs of this disease together with a typical case of progressive supranuclear
palsy.

【Clinical History】

Patient, a 76-year-old woman, has a history
of progressive limb stiffness, weakness, and frequent falls.

【Image Image】

MRI image
Figure 1.
Median sagittal T1WI MR imaging
.

Figure 2.
Axial basal ganglia horizontal T2-FLAIR MR imaging

Figure 3.
T2-FLAIR MR imaging of the horizontal axis of the brain and foot

Figure 4.
Horizontal axial T2-FLAIR MR imaging of the pons

【Discussion】:

T1WI in the middle of cranial MR in patients with PSP shows no signs of
cortical atrophy often occurring in corticobasal degenerative diseases.
Image A is the dorsal lid of the midbrain; b pons; c dorsal pons cover; d Upper and lower mounds
.
The upper edge of the dorsal lid of the midbrain can be seen to be flat and has hummingbird's beak-like changes, reflecting the characteristic atrophy of
PSP dominated by the midbrain.

Figure 5.
T1WI imaging in the median sagittal position

Axial FLAIR imaging, with yellow arrows representing the anteroposterior diameter of the midbrain tegmental cover and yellow arrows for the interfoot fossa.

An increased ratio of the toe fossa to the dorsal midbrain lid suggests PSP lesions
.

Figure 6.
Axial FLAIR imaging

Median sagittal T1WI image from another patient without PSP symptoms:

Figure 7.
a shows the dorsal midbrain cover; b pons; c dorsal pons cover; d Upper and lower mounds

A median sagittal T1WI plot in PSP shows a shortened distance from the papillary body to the posterior edge of the dorsal midbrain cover, resulting in a depression of the inferior wall of the third ventricle:

Figure 8.
Median sagittal T1WI plot

Midbrain atrophy in PSP patients, which resembles the mouth of a hummingbird on MRI images in the median sagittal position, is called hummingbird sign:

Figure 9.
Hummingbird sign

Measuring the mid-brain pontine ratio can increase sensitivity in diagnosing PSP
.
In normal people, the ratio is about 2:3,; The ratio is less than 1:2 in PSP and greater than 2:3
in patients with multiple system atrophy.

Figure 10.
The measurement method of the midbrain pont ratio: a is the midbrain, b is the pons, the yellow line is the vertical line of the long axis of the midbrain and the pons, and the ratio of its length is the midbrain pont ratio

MRI control in patients with and without PSP:

Figure 11.
Patients with PSP on the left and non-PSP on the right

The comparison found that the apical end of the brain was atrophied and the upper edge of the midbrain was flat
in PSP patients.
In addition, in PSP, the anteroposterior diameter of the brain becomes smaller, the aqueduct expands, and the tetraplexic pool increases:

Figure 12.
For Figure 11.
of extensions

【Case study】:

MRI scans of the median sagittal plane play an important role
in the diagnosis of PSP on imaging.
PSP is often accompanied by apical atrophy of the midbrain, with a flat or concave upper edge of the midbrain, and the hummingbird beak manifestation, called hummingbird sign, which is a characteristic atrophy
reflecting the predominance of the midbrain in PSP.
In addition, in PSP patients, the anteroposterior diameter of the brain becomes smaller, the aqueduct expands, the quadrimetric pool increases, and the coronary midbrain looks like a "mouse ear", called the mouse ear sign, which also has certain value
in the diagnosis and differential diagnosis of PSP.
At the same time, measuring the dorsal cover area of the midbrain and the area ratio of the midbrain/pontine section can also be used as another important parameter
to distinguish PSPs from other PDs.

【Key points of diagnosis】:

1.
The clinical symptoms of PSP mainly include backward fall, movement disorders and stiffness, and limited vertical eye movements; Differential diagnoses include Parkinson's disease; Atrophy of multiple systems; Degeneration of the corticobasal ganglia; Lewy body dementia, etc
.

2.
The diagnosis of PSP mainly relies on MRI on imaging;

3.
MRI signs of PSP are mainly hummingbird signs, which are caused by the atrophy of the dorsal lid of the midbrain, the ratio of the toe fossa to the dorsal lid of the midbrain increases, and the base of the pons remains unchanged
.

4.
Measuring the mid-brain pontine ratio can improve sensitivity in diagnosing PSP
.
In normal people, the ratio is about 2:3,; The ratio is less than 1:2 in PSP and greater than 2:3
in patients with multiple system atrophy.