Goiter - pathological enlargement of thyroid
- is observed in a number of thyroid pathologies - diffuse euthyroid goiter,
diffuse toxic goiter, acute thyroiditis, hyperplastic variant of autoimmune
thyroiditis, diffuse-nodular and diffuse-multinodular goiter, adenomatous
goiter, carcinomas, lymphomas.
The term enlargement is traditionally
associated with the change of dimensions and for thyroid it is usually
associated with the volume enlargement. In this context a significant number
of publications is devoted to the study of thyroid dimensions from the
point of view of ultrasonic method and some of them are mentioned in bibliography.
However, it is possible and sufficient to
regard enlargement only as a change of dimensions when estimating
physical objects but for biological tissues and especially for disease
it is highly inconsiderate opinion and discredit of visualization methods
as a whole to use only one sign - enlargement.
Why then is goiter regarded only from the
point of view of organ dimensions being them average or median values for
the definite age, sex, weight, height, surface area? Actually this sign
is extremely important but the ultrasonic method allows to detect the whole
complex of changes described in the atlas.
In goiter the topographic and anatomic interrelation
of thyroid with surrounding organs changes - the upper poles can reach
the upper horns of thyroid cartilage and the lower ones - thoracic part
of trachea and even spread down to the bifurcation of the trachea. The
upper edge of the isthmus can reach cricothyroid ligament.
The form of thyroid significantly changes
- the front surface bulges and shifts to the front, the lateral edge becomes
straight anmd shifts outward. The back surface bulges and shifts to the
spinal column. The median edge shifts to the sagittal line
and repeats the trachea form.
The echostructure and optical density
of thyroid tissue are disturbed.
The changes in trachea appear - its
compression and shift to the spinal column are observed. The extension
of trachea constriction can amount to significant proportions that is clearly
seen in the first 5 to 7 trachea rings.
The esophagus gullet is uniformly deformed
in depth and width.
The anterior group of muscles - musculus
sternothyroideus and sternohyoideus - dramatically thins. The changes in
the posterior group of muscles also appear - the musculus longus capitis,
neck and anterior, medius and posterior musculus scalenus thin and shift
backwards.
The prevertebral fascia consolidates.
The main neck vessels - arteries
and veins - are shifted forward from the sagittal line and backwards.
The venous plethora is observed.
It is rather difficult to see all this range
of ultrasonic signs and it is especially complicated to detect them not
knowing the normal ultrasonic anatomy.
The analysis of tens of thousands of thyroid
ultrasonic images allowed to reveal and understand the dynamic of
the whole range of ultrasonic changes observed in goiter and to use
them in the initial goiter diagnostics.
Method of automatic lateral tomography from
my point of view is the best clinical method of the goiter diagnostics
in the world practice. The two-dimensional thyroid reconstruction by height,
depth and width was succeeded on its base. The step towards three-dimensional
reconstruction of thyroid image and surrounding organs was made.
I hope that the material presented in the
atlas extended the possibilities of ultrasonic method in goiter
diagnostics.
Publishing. Department of International Health and Radiation Research, Atomic Bomb Disease Institute, Nagasaki University School of Medicine, Nagasaki Association for Hibakushas Medical Care (NASHIM), Secretariat of the Cooperation Committee, Japanese Ministry of Foreign Affairs.