Title:Development of Medical Images in Differentiating Benign from Malignant Thyroid Nodules
Volume: 12
Author(s): Wen Luo, Yunfei Zhang and Xiaodong Zhou
Affiliation:
Keywords:
Computed tomography, differential diagnosis, magnetic resonance image, positron-emission tomography,
scintigraphy, thyroid nodule, ultrasonography.
Abstract: As the increasing incidence of thyroid nodules has been recently reported, differential diagnosis
between malignancy and benign nodules plays a critical role for determination of therapy
plans, but is still a challenge for clinicians. Because of uncertain results of fine needle aspiration
(FNA) cytology in some cases, medical images give great noninvasive contribution to differential diagnosis
of thyroid nodules. This review of current literature focused on the development of various
image modalities on thyroid nodules, in order to supply essentials to clinicians for making pretreatment
determination. When ultrasonography is recognized as a routine tool for detecting and differentiating
thyroid nodules, improved accuracy has been found when it is combined with FNA. The
newly-developed modalities of elastography and contrast enhanced ultrasonography could be used
for evaluating the nodule stiffness and vascularity, respectively. Although not recommended as the
first-line tool in the managment guideline, scintigraphy supplies supplementary information of the
indeterminate nodules after FNA, especially in follicular thyroid nodules. Computed tomography(
CT)-detected calcification and its patterns have been regarded to be important sign related to
malignancy. Apparent diffusion coefficient ratios on diffusion-weighted magnetic resonance image(
MRI) are detected significantly lower in malignant nodules than those in benign ones. CT and
MRI are also preferred to demonstrating the surrounding anatomic structures and lymph nodes. The
role of PET and PET/CT in the assessment of nodules has been increased, while SUVmax is attractive
with a cutoff value about 6.0. In conclusion, with their respective functions, the medical image
modalities could supply much helpful information for differential diagnosis of thyroid nodules.