Diagnostic ultrasound ( PDFDrive )

CHAPTER 19 The Thyroid Gland 725
A
B
C
D
E
F
FIG. 19.45 Hashimoto Thyroiditis: Micronodularity. (A) Transverse and (B) longitudinal images of the left lobe demonstrate multiple small
hypoechoic nodules that are lymphocyte iniltration of the parenchyma. (C) and (D) Longitudinal images of another patient show multiple tiny
hypoechoic nodules and increased low on power Doppler. This increased low may indicate an acute phase of the thyroiditis. (E) and (F) Longitudinal
images of a different patient show multiple tiny hypoechoic nodules and decreased low on color Doppler scan. The blood low is normal or
diminished in most cases of Hashimoto thyroiditis.
suggested that hypervascularity occurs when hypothyroidism
develops, perhaps related to stimulation from the associated high
serum levels of thyrotropin (TSH). 151 Oten, cervical lymphadenopathy
is present, most evident near the lower pole of the thyroid
gland (Fig. 19.50). he end stage of chronic thyroiditis is atrophy,
when the thyroid gland is small, with poorly deined margins
and heterogeneous texture caused by progressive ibrosis. Blood
low signals are absent. Occasionally, discrete nodules occur,
and FNA biopsy is needed to establish the diagnosis. 150
Painless (silent) thyroiditis has the typical histologic and
sonographic pattern of chronic autoimmune thyroiditis
(hypoechogenicity, micronodulation, and ibrosis), but clinical
indings resemble classic subacute thyroiditis, with the exception
of node tenderness. Moderate hyperthyroidism with thyroid