What Is Hereditary Spherocytosis?

The balloon , also known as the "spherical balloon", is part of the labyrinth of the inner ear, located in the vestibule, in the shape of a flat pear in front of the oval capsule, and connected to the oval capsule and the volute by small tubes. There is endolymph in the sac, which communicates with the oval sac and the volute. The anterior wall has a thickened mucous membrane, which forms a plaque-like bulge called a balloon plaque.

Chinese name: Balloon
Foreign name: saccule

Also known as: Spherical capsule
Part: Vertebral inner ear labyrinth labyrinth

Balloon Overview

Balloon plaques are formed by a layer of connective tissue, an epithelium, and an otolith membrane. Otolith membrane is a thick protein-like glial membrane covering the surface of epithelium. Its shallow layer contains crystals composed of calcium carbonate and protein, which is called otolith. The plaque epithelium contains both support cells and hair cells. Hair cells are sensory epithelial cells, sandwiched between supporting cells, and are shaped like round-bottomed flasks with narrow upper and lower widths, with vestibular nerve endings distributed at the bottom. There is a tuft of cilia at the top of the hair cells, which extends into the otolith membrane. The connective tissue of the cystic plaque is connected to the periosteum in the vestibule, and nerve fibers pass through it. Capsules are sensors that sense changes in head position or linear acceleration and deceleration. When the position of the head changes, due to the influence of gravity, the otolith membrane sags and pulls the hair cell cilia, which excites and generates nerve impulses, which are transmitted to the brain through the vestibular snail nerves, which generates the sense of position and speed.

MR Balloon MR Anatomy

Balloon Morphological Classification

1. Membrane labyrinth at 60 ° MIP:

The three semicircular canals are fan-shaped and a total of 5 feet are connected to the oval capsule. Each semicircular canal is U-shaped and its size is similar. The cochlear canal gradually turns to the front. The oval capsule and the balloon are connected to form an oval-shaped high signal. Located between the semicircular canal and the volute.

2. Membrane labyrinth 90 ° MIP map:

The outer semicircular canal shows a maximum "C" shape on this map. The anterior and posterior semicircular canals are strip-shaped due to their overlap. The elliptical sac and the balloon still cannot be separated, and the volute turns to the front.

Balloon imaging principle

In recent years, due to the application of MR special software, especially the development of MR water imaging technology, the fine structure of the film labyrinth can be displayed intuitively and three-dimensionally. Membrane labyrinth and internal auditory canal imaging are based on the principle of water imaging, that is, using the heavy T2 weighting effect of long TR and special TE to increase the signal strength of cerebrospinal fluid and lymphatic fluid in the labyrinth of the internal auditory canal to make it extremely high It is in sharp contrast with the surrounding low-signal bone structure, highlighting the images of the inner auditory canal and the labyrinth of the membrane, thereby achieving the "angiography" effect of the inner auditory canal and the labyrinth of membrane. However, the MR water imaging technology is not yet satisfactory to display the labyrinthine tube, to distinguish between endolymphatic fluid and external lymphatic fluid, and to distinguish between the oval capsule and the balloon, which are integrated into a high signal capsule.

Balloon clinical application

MR membrane labyrinth imaging can provide reliable imaging anatomic basis before inner ear microsurgery, especially plays an important role in the selection of cochlear surgery indications, including the exclusion of surgical contraindications and possible normal variations, but it is not suitable for Review after cochlear transplantation. Some scholars have reported that MR can show congenital abnormalities in the inner ear with satisfaction, and understand the degree and location of inner ear non-development and dysplasia, such as Michel malformation, Mondini malformation, cochlear duct dilatation, and otosclerosis. Some scholars have compared the diagnostic value of CT and MR for large vestibular catheters. As a result, MR can directly display the fluid of the endolymphatic vessels and endolymphatic sacs, and can better reflect the morphological changes. Some scholars believe that MR is of great value in the diagnosis of membrane labyrinth lesions, especially enhanced MR membrane labyrinth imaging is easy to detect small tumors in labyrinth. In addition, the diagnosis of labyrinthitis, labyrinthosis, and Meniere's disease is of great significance, but when the morphological changes have not been caused by labyrinthosis, MR cannot show the small changes in the inner ear like gross anatomy.

Balloon clinical examination and diagnosis

1. Hearing function check:

In the pathological study of Meniere's disease, it was found that the order of hydrocephalus in the membrane was cochlea, balloon, oval capsule, and semicircular canal. Therefore, the auditory function test was first used for the diagnosis basis and prognosis of the labyrinthine membrane. The characteristics of pure tone hearing threshold curve and the change of hearing threshold curve in glycerol test can provide evidence for membrane labyrinth. Hearing loss caused by membrane labyrinth has a volatile nature, which makes auditory function tests have certain limitations in determining the damage of membrane labyrinth to inner ear damage.

2. Vestibular evoked myogenic potential ( VEMP):

It is a test to evaluate the function of the balloon and inferior vestibular nerve in recent years. The methods, equipment and applications have not been standardized, but it is helpful for the anatomical positioning of inner ear diseases and has clinical value in the diagnosis of balloon hydrops.

3. Vestibular function check:

Clinically used electroencephalogram tests are mainly to evaluate the function of bilateral horizontal semicircular canals, not the function of otoliths, which include balloons and oval capsules. Therefore, the results of electromyography can only indicate the changes in the inner ear function caused by the presence of membranous labyrinth, including the irritation period and functional paralysis period, which can help the clinical staging of labyrinth fluid.