An ultrasound model to discriminate the risk of thyroid carcinoma

Distribution patterns of microcalcifications in suspected thyroid carcinoma: a classification method helpful for diagnosis

PURPOSE

The aim of this study was to compare the distribution patterns of microcalcifications in thyroid cancers with benign cases.

METHODS

In total, 358 patients having microcalcifications on ultrasonography were analysed. Microcalcifications were categorised according to the distribution patterns: (I) microcalcifications inside one (a) or more (b) suspected nodules, (II) microcalcifications not only inside but also surrounding a suspected single (a) or multiple (b) nodules, and (III) focal (a) or diffuse (b) microcalcifications in the absence of any suspected nodule. Differences in distribution patterns of microcalcifications in benign and malignant thyroid lesions were compared.

RESULTS

We found that the distribution patterns of microcalcifications differed between malignant (n = 325) and benign lesions (n = 117) (X ² = 9.926, p < 0.01). Benign lesions were classified as type Ia (66.7%), type Ib (29.1%) or type IIIa (4.3%). The specificity of type II and type IIIb in diagnosing malignant cases was 100%. Among malignant lesions, 172 locations were classified as type Ia, 106 as type Ib, 12 as type IIa, 7 as IIb, 7 as type IIIa and 19 as type IIIb. Accompanying Hashimoto thyroiditis was most frequent in type III (51.6%).

CONCLUSIONS

Types II and IIIb are highly specific for cancer detection. Microcalcifications outside a nodule and those detected in the absence of any nodule should therefore be reviewed carefully in clinical practice.

KEY POINTS

• A method to classify distribution patterns of thyroid microcalcifications is presented. • Distribution features of microcalcifications are useful for diagnosing thyroid cancers. • Microcalcifications outside a suspicious nodule are highly specific for thyroid cancers. • Microcalcifications without suspicious nodules should also alert the physician to thyroid cancers.

Pediatric thyroid nodules: ultrasonographic characteristics and inter-observer variability in prediction of malignancy

BACKGROUND

Pediatric thyroid nodules, while uncommon, have high malignancy risk. The objectives of the study were (1) to identify sonographic features predictive of malignancy; (2) to create a prediction model; and (3) to assess inter-observer agreement among radiologists.

METHODS

All available cases of thyroid nodules, surgically removed between 2000 and 2009. Three radiologists reviewed the sonographic images; 2 pathologists reviewed the tissue specimens. Adult prediction models were applied. Interobserver variability was assessed.

RESULTS

Twenty-seven subjects, mean age 13.1±3.4 years, were included. Nineteen nodules were differentiated thyroid carcinomas. On multivariate analysis, size was the only significant predictor of malignancy. On recursive partitioning analysis, size >35 mm with microcalcification and ill-defined margins yielded the best prediction model. Radiologist inter-observer agreement regarding malignancy was moderate (κ=0.50).

CONCLUSIONS

Larger size, microcalcifications and ill-defined margins on ultrasound demonstrate the best predictive model for malignancy in the pediatric population. Experienced pediatric radiologists demonstrate moderate inter-observer agreement in prediction of malignancy.

A new computational model for human thyroid cancer enhances the preoperative diagnostic efficacy

Considering the high rate of missed diagnosis and delayed treatments for thyroid cancer, an effective systematic model for the differential diagnosis is highly needed. Thus we analyzed the data on the clinicopathological characteristics, routine laboratory tests and imaging examinations in a cohort of 13,980 patients with thyroid cancer to establish a new diagnostic model for differentiating thyroid cancer in clinical practice. Here, we randomly selected two-thirds of the population to develop the thyroid malignancy risk scoring system (TMRS) for preoperative differentiation between thyroid cancer and benignant thyroid diseases, and then validated its differential diagnostic power in the rest one-third population. The 18 predictors finally enrolled in the TMRS included male gender, clinical manifestations (fever, neck sore, neck lump, palpitations or sweating), laboratory findings (TSH>1.56mIU/L, FT3>5.85pmol/L, TPOAb>14.97IU/ml, TgAb>48.00IU/ml, Tg>34.59μg/L, Ct>64.00ng/L, and CEA>0.41μg/L), and ultrasound features (tumor number≤ 23mm, site, size, echo texture, margins, and shape of neck lymphnodes). The TMRS is validated to be well-calibrated (P = 0.437) and excellently discriminated (AUC = 0.93, 95% CI [0.92, 0.94]), with an accuracy of 83.2%, a sensitivity of 89.3%, a specificity of 81.5%, positive and negative predictive values of 56.8% and 96.6%, positive and negative likelihood ratios of 4.83 and 0.13 in the development cohort, respectively. The TMRS highlights that this differential diagnostic system could help provide accurate preoperative risk stratification for thyroid cancer, and avoid unnecessary over- and under-treatment for such patients.

Thyroid nodule ultrasound: technical advances and future horizons

Thyroid nodules are extremely common and the vast majority are non-malignant; therefore the accurate discrimination of a benign lesion from malignancy is challenging. Ultrasound (US) characterisation has become the key component of many thyroid nodule guidelines and is primarily based on the detection of key features by high-resolution US. The thyroid imager should be familiar with the strengths and limitations of this modality and understand the technical factors that create and alter the imaging characteristics. Specific advances in high-resolution US are discussed with reference to individual features of thyroid cancer and benign disease. Potential roles for three-dimensional thyroid ultrasound and computer-aided diagnosis are also considered. The second section provides an overview of current evidence regarding thyroid ultrasound elastography (USE). USE is a novel imaging technique that quantifies tissue elasticity (stiffness) non-invasively and has potential utility because cancers cause tissue stiffening. In recent years, there has been much research into the value of thyroid USE for distinguishing benign and malignant nodules. Preliminary findings from multiple pilot studies and meta-analyses are promising and suggest that USE can augment the anatomical detail provided by high-resolution US. However, a definite role remains controversial and is discussed.

TEACHING POINTS

• High-resolution US characterises thyroid nodules by demonstration of specific anatomical features • Technical advances heavily influence the key US features of thyroid nodules • Most papillary carcinomas appear stiffer than benign thyroid nodules on US elastography (USE) • Thyroid USE is controversial because of variation in the reported accuracies for malignancy • Combined grey-scale US/USE may lower the FNAC rate in benign nodules.

Evaluating thyroid nodules: predicting and selecting malignant nodules for fine-needle aspiration (FNA) cytology

Objective

To form and assess a set of diagnostic ultrasound criteria to select malignant nodules for fine-needle aspiration (FNA) cytology and reduce number of FNA biopsies.

Methods

In this prospective observational service evaluation study, 171 thyroid nodules that underwent FNA cytology were independently scored by two observers for established nodular sonographic characteristics for malignancy. The final diagnosis was confirmed by surgery or a 6-month follow-up in nodules with benign cytology.

Results

Logistic regression analysis and receiver operating characteristic curve analysis results indicate good and comparable predictive powers of certain ultrasound characteristics in predicting malignancy. The highest sensitivity in detecting malignancy was achieved when taking together the information of marked hypoechogenicity, microcalcification and mixed central/peripheral or central Doppler colour flow pattern. A sensitivity of 100 % and a specificity of 76 % were obtained in detecting malignant nodules using this criteria.

Conclusions

Our study proposes a set of ultrasound and colour Doppler criteria to safely select malignant thyroid nodules for FNA cytology.

Main messages:

• There is a need to safely select malignant nodules for FNA cytology and reduce unnecessary FNA

• Some ultrasound features are specific but none are independently/fully predictive of malignancy

• We have prospectively tested a set of ultrasound criteria for selecting nodules for FNA cytology

• Our ultrasound criteria detected malignant nodules with a 100 % sensitivity and 76 % specificity

• A high sensitivity is clinically desirable as it selects many, if not all, malignant nodules for FNA