Three-Dimensional Ultrasound in Small Parts

Comparison of two- and three-dimensional sonography for the prediction of the extrathyroidal extension of papillary thyroid carcinomas

BACKGROUND/AIMS

The purpose of this study was to compare the diagnostic validity of two-dimensional (2D) and three-dimensional (3D) ultrasonography (US) when predicting the extrathyroidal extension of papillary thyroid cancer.

METHODS

All 2D data were interpreted in real time and 3D data were stored, rendered using tomographic ultrasound imaging (TUI), and then reviewed retrospectively.

RESULTS

Extrathyroidal extension was present in 17 papillary thyroid cancers(24.3%) on pathology reports. The presence of contact was significantly associated with extrathyroidal extension on both 2D and 3D US (p = 0.007 and p = 0.003), and the sensitivity and specificity were not significantly different between 2D and 3D US (p = 1.000 and p = 0.754). The coexistence of protrusion and contact was not significantly associated with extrathyroidal extension on either 2D or 3D sonogram.

CONCLUSIONS

Three-dimensional images rendered with TUI algorithms alone do not seem to be markedly superior to real-time 2D US in predicting the extrathyroidal extension of papillary thyroid cancer.

Comparison between Thin-Slice 3-D Volumetric Ultrasound and Conventional Ultrasound in the Differentiation of Benign and Malignant Thyroid Lesions

We explored the efficacy of thin-slice volumetric 3-D ultrasound (3-DUS) in distinguishing between benign and malignant thyroid nodules. A total of 103 thyroid nodules were evaluated prospectively using 3-D gray-scale ultrasonography. The shape, margin, halo and potential capsular invasion of the nodules were compared with the findings of conventional 2-D ultrasound (2-DUS). Of the 103 thyroid nodules, there were 50 pathologically confirmed benign lesions and 53 malignant lesions (51.5%). Shape irregularity, ill-defined margins and capsular invasion provided sensitivities of 90.0%, 47.2% and 39.6% and specificities of 88.0%, 84.0% and 100%, respectively, for the malignant lesions. The diagnosis of thyroid cancer was improved in 3-DUS compared with 2-DUS, with a sensitivity of 88.7%, specificity of 90.0%, positive predictive value of 90.4%, negative predictive value of 88.2% and accuracy of 89.3%. The sensitivity of detection for lesions with capsular invasion increased to 39.6% with 3-DUS, more than twice that of 2-DUS. Three-dimensional US is highly accurate in diagnosing thyroid nodules, particularly those with capsular invasion.

Extrathyroid extension of well-differentiated papillary thyroid microcarcinoma on US

BACKGROUND

Extrathyroidal extension is an important factor to determine the extent of thyroid surgery. The aim of the present study was to evaluate the usefulness of high-resolution ultrasound (US) for predicting the extrathyroidal extension of papillary thyroid microcarcinoma (PTMC).

METHODS

This study included a total of 221 PTMCs in 181 patients. PTMC was defined as thyroid papillary carcinoma equal or less than 1 cm in size. The US findings, such as contact and disruption of thyroid capsule, were evaluated to predict the extrathyroidal extension of thyroid carcinoma. We calculated the diagnostic accuracy and odds ratio for each US finding.

RESULTS

Of the 221 PTMCs, extrathyroidal extension was present in 89 (40.3%) based on pathologic results. The mean size was not significantly different between PTMCs with and without extrathyroidal extension (p = 0.527). When the degree of contact was high, extrathyroidal extension of the thyroid cancer was high (p < 0.0001). Considering the odds ratio, Az value, and positive predictive value of each US finding, more than 25% contact with the adjacent capsule is the most accurate measurement for predicting extrathyroidal extension.

CONCLUSIONS

This study suggests that the presence and degree of contact between a PTMC and the adjacent capsule as found on preoperative US can provide an useful predictive information about an extrathyroidal extension.

Renal sonography with 2-dimensional versus cine organ imaging: preliminary results

OBJECTIVE

This pilot study was undertaken to determine whether cine organ imaging (COI) of the entire kidney yields a quicker and equally diagnostic study compared with traditional 2-dimensional (2D) scanning.

METHODS

Fifty-seven adult patients referred for diagnostic renal sonography underwent 2D sonography followed by COI performed by a second sonographer, who was blinded to the results of the first examination. Images were interpreted blindly by 2 independent readers in 2 separate reading sessions divided into 2D or COI image sets for each patient. The acquisition time and interpretation time of each protocol were recorded. Images were scored for the percentage of kidney visualized and for the presence or absence of hydronephrosis, stones, cysts, and renal lesions (non-simple cysts and solid masses).

RESULTS

The average acquisition time decreased from 13.3 to 10.5 minutes between 2D and COI studies, respectively (P = .02). The average image interpretation time increased 37 seconds (P < .0001). A greater percentage of parenchymal visualization was achieved with COI versus 2D imaging. There was no significant difference in detection of renal abnormalities (hydronephrosis, stones, renal cysts, and masses) between the 2 modes, although the detection of cysts on COI was equal to or greater than that on 2D imaging on a per-patient basis.

CONCLUSIONS

Cine organ imaging decreased the acquisition time significantly while retaining and possibly improving diagnostic quality. The minimally increased interpretation time may be decreased in the future by fewer volume acquisitions per patient. Further investigations will be needed to assess the impact of color Doppler imaging in volumetric protocols as well as to compare renal lesion detection versus computed tomography and magnetic resonance imaging.

Peripheral neurogenic tumors: is the use of different types of imaging diagnostically useful?

We report a series of six benign peripheral neurogenic tumors (five schwannomas and one neurofibroma) studied by 3D ultrasonography (US) and magnetic resonance imaging (MRI). The findings demonstrated by US and MRI are variable, but usually permit the diagnosis of benign nervous tumor without prejudging the final histological diagnosis. MRI does not bring forward further complementary images to those observed at US, which is limited by its dependence on its operator. The use of 3D US will be sufficient for the diagnosis and preoperative evaluation of a lesion when it is possible to furnish the volumetric data and the tools necessary for data analysis in a single document (in a CD).