Accuracy of three-dimensional ultrasound for thyroid volume measurement in children and adolescents

Inter-observer variation in two-dimensional and three-dimensional ultrasound measurement of papillary thyroid microcarcinoma

BACKGROUNDS

The reliable ultrasound (US) measurements of papillary thyroid microcarcinoma (PTMC) are very important during active surveillance. This prospective study was design to investigate the inter-observer reliability and agreement of two- dimensional ultrasound(2DUS) and three-dimensional ultrasound(3DUS) in the measurement of maximum diameter and volume for PTMC.

METHODS

This prospective study included 51 consecutive patients with solitary PTMC confirmed by biopsy. Two independent observers performed measurements of each tumor using a standardized measurement protocol. The maximum diameter was the largest one of the three diameters measured on the largest transverse and longitudinal 2DUS images. 2DUS volume was calculated using ellipsoid formula method. The virtual organ computer aided analysis(VOCAL) was used to determine 3DUS volume. The inter-observer reliability was assessed using intraclass correlation coefficient(ICC) with 95% confidence intervals(CIs). Bland-Altman analysis was used to evaluate agreement, and expressed as a bias with 95% limits of agreement(LOA).

RESULTS

The maximum diameter was 0.78 ± 0.14 cm. Volume measured by 3DUS was significantly smaller than that by 2DUS(0.163 ± 0.074 cm3 vs. 0.175 ± 0.078 cm3, P = 0.005). The ICCs of inter-observer reliability of maximum diameter, 2DUS volume and 3DUS volume was 0.922(0.864-0.955), 0.928(0.874-0.959), and 0.974(0.955-0.985), respectively. The ICCs of 2DUS and 3DUS volume was 0.955(0.909-0.976). The inter-observer agreement of maximum diameter, 2DUS volume and 3DUS volume was 1.096(0.7322 to 1.459), 1.008(0.5802-1.435), and 1.011(0.7576-1.265), respectively. The inter-observer agreement of 2DUS and 3DUS volume was 1.096(0.7322 to 1.459).

CONCLUSION

Maximum diameter had the lowest degree of observer variation among all the measurements. Volume measured by 3DUS had lower variability and higher repeatability than that by 2DUS, which might be helpful to provide more reliable estimates of tumor size for PTMC.

Optimization of Thyroid Volume Determination by Stitched 3D-Ultrasound Data Sets in Patients with Structural Thyroid Disease

Ultrasound (US) is the most important imaging method for the assessment of structural disorders of the thyroid. A precise volume determination is relevant for therapy planning and outcome monitoring. However, the accuracy of 2D-US is limited, especially in cases of organ enlargements and deformations. Software-based "stitching" of separately acquired 3D-US data revealed precise volume determination in thyroid phantoms. The purpose of this study is to investigate the feasibility and accuracy of 3D-US stitching in patients with structural thyroid disease. A total of 31 patients from the clinical routine were involved, receiving conventional 2D-US (conUS), sensor-navigated 3D-US (3DsnUS), mechanically-swept 3D-US (3DmsUS), and I-124-PET/CT as reference standard. Regarding 3DsnUS and 3DmsUS, separately acquired 3D-US images (per thyroid lobe) were merged to one comprehensive data set. Subsequently, anatomical correctness of the stitching process was analysed via secondary image fusion with the I-124-PET images. Volumetric determinations were conducted by the ellipsoid model (EM) on conUS and CT, and manually drawn segmental contouring (MC) on 3DsnUS, 3DmsUS, CT, and I-124-PET/CT. Mean volume of the thyroid glands was 44.1 ± 25.8 mL (I-124-PET-MC = reference). Highly significant correlations (all p < 0.0001) were observed for conUS-EM (r = 0.892), 3DsnUS-MC (r = 0.988), 3DmsUS-MC (r = 0.978), CT-EM (0.956), and CT-MC (0.986), respectively. The mean volume differences (standard deviations, limits of agreement) in comparison with the reference were -10.50 mL (±11.56 mL, -33.62 to 12.24), -3.74 mL (±3.74 mL, -11.39 to 3.78), and 0.62 mL (±4.79 mL, -8.78 to 10.01) for conUS-EM, 3DsnUS-MC, and 3DmsUS-MC, respectively. Stitched 3D-US data sets of the thyroid enable accurate volumetric determination even in enlarged and deformed organs. The main limitation of high time expenditure may be overcome by artificial intelligence approaches.

Tracked 3D ultrasound and deep neural network-based thyroid segmentation reduce interobserver variability in thyroid volumetry

Thyroid volumetry is crucial in the diagnosis, treatment, and monitoring of thyroid diseases. However, conventional thyroid volumetry with 2D ultrasound is highly operator-dependent. This study compares 2D and tracked 3D ultrasound with an automatic thyroid segmentation based on a deep neural network regarding inter- and intraobserver variability, time, and accuracy. Volume reference was MRI. 28 healthy volunteers (24—50 a) were scanned with 2D and 3D ultrasound (and by MRI) by three physicians (MD 1, 2, 3) with different experience levels (6, 4, and 1 a). In the 2D scans, the thyroid lobe volumes were calculated with the ellipsoid formula. A convolutional deep neural network (CNN) automatically segmented the 3D thyroid lobes. 26, 6, and 6 random lobe scans were used for training, validation, and testing, respectively. On MRI (T1 VIBE sequence) the thyroid was manually segmented by an experienced MD. MRI thyroid volumes ranged from 2.8 to 16.7ml (mean 7.4, SD 3.05). The CNN was trained to obtain an average Dice score of 0.94. The interobserver variability comparing two MDs showed mean differences for 2D and 3D respectively of 0.58 to 0.52ml (MD1 vs. 2), −1.33 to −0.17ml (MD1 vs. 3) and −1.89 to −0.70ml (MD2 vs. 3). Paired samples t-tests showed significant differences for 2D (p = .140, p = .002 and p = .002) and none for 3D (p = .176, p = .722 and p = .057). Intraobsever variability was similar for 2D and 3D ultrasound. Comparison of ultrasound volumes and MRI volumes showed a significant difference for the 2D volumetry of all MDs (p = .002, p = .009, p <.001), and no significant difference for 3D ultrasound (p = .292, p = .686, p = 0.091). Acquisition time was significantly shorter for 3D ultrasound. Tracked 3D ultrasound combined with a CNN segmentation significantly reduces interobserver variability in thyroid volumetry and increases the accuracy of the measurements with shorter acquisition times.

A review of sonographic thyroid volume and iodine sufficiency in children: An Australian perspective

Sonographic measurement of the thyroid gland volume is a safe and reliable method for epidemiologic studies in iodine deficiency disorders. Several factors such as age, sex and anthropometric characteristics are known to be the determinants of thyroid gland size but the most widely studied is the effect of insufficient iodine intake. Low iodine intake induces enlargement of the thyroid gland known as goitre. The assessment of urinary iodine concentration alone is not reliable as it can vary daily within individuals. Urinary iodine concentration in conjunction with sonographic thyroid gland measurements is a widely used method of thyroid gland assessment. Establishment of normative thyroid volume is essential for the assessment of iodine deficiency disorders, and studies have been conducted in several countries. These studies have shown that thyroid gland volumes are likely population-specific even in iodine-sufficient countries limiting the effectiveness of international reference ranges. Based on currently available data of sonographic thyroid gland volume measurements and how they vary across populations of school children, this review argues for the establishment of population-specific reference ranges in regions such as Australia, which are now considered iodine-sufficient.

Estimation of thyroid volume from scintigraphy through 2D/3D registration of a statistical shape model

Accurate measurement of thyroid volume is important for thyroid disease diagnosis and therapy. In nuclear medicine, the thyroid volume is usually estimated from scintigraphy images using empirical equations. However, due to the lack of volumetric information from the scintigraphy image, the accuracy of equation-based estimation is imperfect. To solve this problem, this paper proposes a method which registers a 3D thyroid statistical shape model (SSM) to a single-view scintigraphy image to achieve more accurate volume estimation. The SSM was constructed based on a training set of segmented 3D CT images, and the thyroid shape variations between the training subjects were modelled using the point distribution model. For thyroid volume estimation, the SSM was projected into the scintigraphy image of the target patient, and then the projected model shape was nonrigidly registered with the patient's scintigraphy image. The resultant 2D deformation file was back-projected to 3D space to guide the deformation of the 3D SSM. This process was repeated iteratively until convergence, and the volume of the finally deformed SSM was considered as the estimation of the patient's thyroid volume. For validation, this method was evaluated based on a test set of 20 scintigraphy images, achieving an estimation error of  -2.10%  ±  5.20% which was much less than the error of the conventional equation-based method (35.76%  ±  15.20%) based on the same test set. The robustness of this method was further tested using a challenging case, i.e. a scintigraphy image with a large thyroid tumor. For this case, the volume estimation error was only 6.08%. Our method has significantly improved the accuracy of thyroid volume estimation from scintigraphy images, and it will enhance the value of scintigraphy imaging for thyroid disease diagnosis and radioiodine therapy.

3D ultrasound DICOM data of the thyroid gland

Purpose: It has recently become possible to generate and archive three-dimensional ultrasound (3D-US) volume data with the DICOM standard Enhanced Ultrasound Volume Storage (EUVS). The objective of this study was to examine the application of the EUVS standard based on the example of thyroid ultrasound. Patients, methods: 32 patients, who were referred for thyroid diagnosis, were given a 3D-US examination of the thyroid gland (GE Voluson E8, convex 3D probe RAB4–8-D). The 3D data sets were exported to EUVS. Necessary additions to DICOM entries and transformation into an established DICOM standard were carried out. The visual assessment and volume measurements were performed by two experts on nuclear medicine using standard software in our hospital. Results: In 24/32 (75%) of the patients, the whole organ was successfully recorded in a single 3D scan; in 8/32 (25%), only part of organ could be covered. In all cases, 3D-US data could be exported and archived. After supplementing the DICOM entry Patient Orientation and transformation into the DICOM PET format, 3D-US data could be displayed in the correct orientation and size at any viewing workstation and any web browser-based PACS viewer. Afterwards, 3D processing such as multiplanar reformation, volumetric measurements and image fusion with data of other cross sectional modalities could be performed. The intraclass correlation of the volume measurements was 0,94 and the interobserver variability was 5.7%. Conclusion: EUVS allows the generation, distribution and archiving of 3D-US data of the thyroid, facilitates a second reading by another physician and creates conditions for advanced 3D processing using routine software

Off-site evaluation of three-dimensional ultrasound for the diagnosis of thyroid nodules: comparison with two-dimensional ultrasound

OBJECTIVES

We compared the diagnostic performance of off-site evaluation between prospectively obtained 3D and 2D ultrasound for thyroid nodules.

METHODS

3D and 2D ultrasonographies were preoperatively obtained from 85 consecutive patients (mean age, 51 years; age range, 28-83 years) who were referred for a total thyroidectomy. Three radiologists independently evaluated 3D and 2D images of 91 pathologically confirmed thyroid nodules (30 benign and 61 malignant nodules) for nodule characterization. Diagnostic performance, interobserver agreement and time for scanning were compared between 3D and 2D.

RESULTS

3D had significantly higher sensitivities than 2D for predicting malignancy (78.7 % vs. 61.2 %, P < 0.01) and extrathyroidal extension (66.7 % vs. 46.4 %, P = 0.03) in malignancy. In terms of specificities, there were no statistically significant differences between 2D and 3D for predicting malignancy (78.4 % vs. 74.8 %, P = 1.00) and extrathyroidal extension (63.6 % vs. 57.6 %, P = 0.46). With respect to interobserver agreement, 3D showed moderate agreement (κ = 0.53) for predicting extrathyroidal extension in malignancy compared with 2D ultrasound, which showed fair agreement (κ = 0.37). 3D saved time (30 ± 56.52 s) for scanning compared with 2D.

CONCLUSION

For off-site evaluation, 3D US is more useful for diagnosis of thyroid nodules than 2D US.

KEY POINTS

• 3D had higher sensitivity than 2D for predicting malignancy and extrathyroidal extension. • 3D showed better agreement for predicting extrathyroidal extension in malignancy than 2D. • 3D thyroid ultrasound saved time for scanning compared with 2D. • For off-site evaluation of thyroid nodules, 3D is more useful than 2D.

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.

Developing an accurate method for estimating thyroid volume in calves using ultrasonography

Diseases of the thyroid gland with struma formation can occur in calves suffering from iodine deficiency. The aim of the study was to develop a guideline for standardized ultrasonographic examination of the thyroid gland in order to determine its volume. Sonographic measurements of the thyroid lobes were carried out on three standardized axes in calves up to 3 months of age (n = 83). Total volume (V SON ) was calculated using the formula for an ellipsoid body. Forty three of the enrolled animals were euthanized. The lobes of their thyroid glands were dissected and measured with a slide gauge, and V SLG was calculated accordingly. In addition, thyroid volume was measured using the method of water displacement (V AQU ) and this was used as a gold standard in correlation and regression analyses with sonographic and slide gauge values. Intraobserver variability of sonographic measurements was dependent on side and axis, and ranged between 3.04% and 7.35%. In the euthanized calves with a body mass of 52.4 ± 17.1 kg, V SLG was 4.5 ± 1.4 ml, V SON was 6.5 ± 1.7 ml, and V AQU was 7.9 ± 2.4 ml (mean ± standard deviation). Instead of the formula for ellipsoid bodies which underestimates thyroid volume, we developed a new formula derived from regression analysis. Body mass and thyroid volume correlated significantly. With the formula presented, thyroid volume of calves can be estimated by ultrasonographic measurement of three axes and compared to predicted values based on body mass.

Multimodal evaluation of 2-D and 3-D ultrasound, computed tomography and magnetic resonance imaging in measurements of the thyroid volume using universally applicable cross-sectional imaging software: a phantom study

A precise estimate of thyroid volume is necessary for making adequate therapeutic decisions and planning, as well as for monitoring therapy response. The goal of this study was to compare the precision of different volumetry methods. Thyroid-shaped phantoms were subjected to volumetry via 2-D and 3-D ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI). The 3-D US scans were performed using sensor navigation and mechanical sweeping methods. Volumetry calculation ensued with the conventional ellipsoid model and the manual tracing method. The study confirmed the superiority of manual tracing with CT and MRI volumetry of the thyroid, but extended this knowledge also to the superiority of the 3-D US method, regardless of whether sensor navigation or mechanical sweeping is used. A novel aspect was successful use of the same universally applicable cross-imaging software for all modalities.

3D ultrasonography is as accurate as low-dose CT in thyroid volumetry

AIM

The purpose of this study was to compare thyroid volumetry by three-dimensional mechanically swept ultrasonography (3DmsUS) and low-dose computed tomography (ldCT).

PATIENTS, METHODS

30 subjects referred for radioiodine therapy of benign thyroid diseases were subjected to 3DmsUS and ldCT. A prerequisite of 3DmsUS analyses was that the scans had to capture the entire thyroid, excluding therefore cases with a very large volume or retrosternal portions. The 3DmsUS data were transformed into a DICOM format, and volumetry calculations were performed via a multimodal workstation equipped with standard software for cross-sectional imaging. Volume was calculated applying both the ellipsoid model and a manually tracing method. Statistical analyses included 95% confidence intervals (CI) of the means and limits of agreement according to Bland and Altman, the latter including 95% of all expected values.

RESULTS

Volumetric measurements by 3DmsUS and ldCT resulted in very high, significant correlation coefficients, r = 0.997 using the ellipsoid model and r = 0.993 with the manually tracing method. The mean relative differences of the two imaging modalities proved very small (-1.2±4.0% [95% CI -2.62; 0.28] using the ellipsoid model; -1.1±5.2% [95% CI -2.93; 0.80] using the manually tracing method) and the limits of agreement sufficiently narrow (-9.1% to 6.8%; -11.3% to 9.2%, respectively).

CONCLUSION

For moderately enlarged thyroids, volumetry with 3DmsUS proved comparable to that of ldCT, irrespective of whether the ellipsoid model or the manually tracing method was applied. Thus, 3DmsUS qualifies as a potential alternative to ldCT, provided that the organ is completely accessible. The use of a standard workstation for cross-sectional imaging with routine software did not prove problematic.

Use of spiral computed tomography volumetry for determining the operative approach in patients with Graves' disease

BACKGROUND

The purposes of the present study were to assess (1) the correlation between the weight of the postoperative thyroid specimen and the spiral computed tomography (CT) volumetry results of the thyroid gland in patients with Graves' disease, and (2) the utility of CT volumetry for determining the operative approach.

METHODS

From 2009 to 2010, a total of 56 patients with Graves' disease underwent total or subtotal thyroidectomy. An enhanced spiral CT was taken in all patients prior to the operation. From 2.5 mm-thick slices of the thyroid gland, the surface area was calculated to measure the volume of the thyroid gland. The glandular volume was compared to the weight of the postoperative thyroid specimen.

RESULTS

A total of 42 and 14 patients underwent total and subtotal thyroidectomy, respectively. The mean weight of the postoperative thyroid specimen was 43.9 ± 33.4 g, and the mean volume obtained by CT volumetry was 44.2 ± 32.8 mL. A good correlation was observed between the weight of the postoperative thyroid specimen and the volume calculated by CT (r = 0.98, p < 0.001). When 100 mL was set as the higher cut-off value of the thyroid volume for minimally invasive thyroid surgery, the estimated blood loss showed a significant difference between the >100 mL and the ≤100 mL groups (608.3 ± 540.8 vs. 119.7 ± 110.4 mL; p = 0.036).

CONCLUSIONS

Spiral CT volumetry may be used to measure the thyroid volume reliably in patients with Graves' disease. For cases in which surgery is indicated in patients with Graves' disease, CT volumetry provides useful information from which to determine the operative approach. One hundred milliliter or less of thyroid volume in CT volumetry is recommended to perform minimally invasive thyroid surgery.

The reproducibility of the virtual organ computer-aided analysis program for evaluating 3-dimensional power Doppler ultrasonography of diffuse thyroid disorders

AIM

The aim of this study was to evaluate the intra- observer and inter-observer reproducibility of 3-dimensional (3D) power Doppler ultrasonography with the virtual organ computer-aided analysis (VOCAL) program for measuring thyroid volume and vascular indices in patients with diffuse thyroid disorders.

MATERIALS AND METHODS

Patients with diffuse goiters were examined by 3D ultrasonography from August 2005 to July 2006. The parameters for vascular assessment included the vascularization index (VI), flow index (FI), vascularization-flow index (VFI), and thyroid size, and were obtained using the VOCAL program. This program used plane A and a 30 degrees rotational step. Intra-observer and inter-observer repeatability are presented as intra-class correlation coefficient (intra-CC) and inter-class correlation coefficient (inter-CC), with values >0.70 being acceptable.

RESULTS

Sixty-three patients in total were enrolled for this study, including 19 patients with simple goiter and 44 patients with autoimmune thyroid disease (AITD) (23 Graves' disease, 21 Hashimoto's thyroiditis). Thyroid volume and 3 vascular indices showed excellent reproducibility in the AITD group (intra- CC>0.9373 and inter-CC>0.8763) and its subgroups. The VI had excellent consistent reproducibility in the simple goiter group (intra-CC>0.8987 and inter-CC>0.8881), but the other parameters did not.

CONCLUSIONS

Based on this study, 3D power Doppler ultrasonography with the VOCAL program is a reliable tool for evaluating diffuse thyroid disorders due to an autoimmune process. The VI is the most reliable parameter.

Thyroid volumetric quantification: comparative evaluation between conventional and volumetric ultrasonography

OBJECTIVE

Thyroid volume quantification is an important parameter for radiotherapy dosing in cases of major thyroid diseases such as thyroiditis and carcinoma. In clinical practice, this calculation is performed by means of ultrasonography on the basis of an ellipsoid formula obtained from the 3 axes. The aim of our study was to compare the accuracy of volume calculation between B-mode ultrasonography and volumetric ultrasonography (VUS).

METHODS

Between April and May 2007, 27 consecutive patients selected for thyroidectomy were prospectively evaluated. One expert ultrasound operator calculated each thyroid volume with standard B-mode ultrasonography on the basis of the 3 axes of each lobe, and then the patients were analyzed with an offline workstation equipped with volumetric probes (VUS). On the offline workstation, 2 separate blinded operators (VUS1 and VUS2) calculated the thyroid volume with virtual organ computer-aided analysis. Data acquired were then compared with pathologic anatomy (PA).

RESULTS

The mean time for B-mode analysis was 6 minutes, whereas VUS analysis needed a mean time of 16.5 minutes. Interobserver variability between the median VUS1 and VUS2 measurements was 0.36 mL (interquartile range [IQR], -0.79 to 0.37 mL; P < .156). The median variability between B-mode ultrasonography and PA was -9.6 mL (IQR, -16.7 to 1.5 mL; P < .001), and that between VUS and PA was -2.87 mL (IQR, -11.97 to 9.51 mL; P = .019). The overall performance of B-mode ultrasonography in comparison with PA was -29.1% (IQR, -47.5% to -5.9%), and that of VUS in comparison with PA was -6.3% (IQR, -26.3 to 13.7%; P < .001).

CONCLUSIONS

Volumetric ultrasonography is a valid tool that compares better with PA than does B-mode ultrasonography.

Interobserver and Intraobserver Variability in the Sonographic Measurement of the Size of the Thyroid Gland by Extended Field-of-View Sonography

Significant intra- and interobserver variation has been reported for estimating the dimensions and the volume of the thyroid gland by conventional sonography in adults. This study aimed to assess the role of extended field-of-view (EFOV) sonography for evaluating the size of the thyroid gland. The mediolateral, anteroposterior, and craniocaudal diameters of both thyroid lobes as well as total thyroid volumes of 30 female patients with the clinical diagnosis of goiter were measured three times by three radiologists with the EFOV sonography technique. Based on these findings, the correlation between the measurements of different operators and different measurements of the same operator was investigated. The interobserver variations for craniocaudal diameters of the right and left thyroid lobes were 3.3% ± 1.9% (mean ± SD) and 2.8% ± 1.3% (mean ± SD), respectively ( P = .012), which were lower than the variations calculated for transverse and mediolateral diameters. The interobserver variation for the calculation of the total glandular volume was 6.3% ± 3.8% (mean ± SD). The intraobserver variations for the three radiologists assessing the total thyroid volume were 4.9% ± 3.0%, 4.2% ± 2.4%, and 4.5% ± 1.7% (all mean ± SD), respectively ( P = .521). EFOV sonography should be considered as an alternative technique for the dimension measurements of the thyroid gland, particularly in cases with goiter.

Quantification of thyroid volume using 3-D ultrasound imaging

Ultrasound (US) is among the most popular diagnostic techniques today. It is non-invasive, fast, comparably cheap, and does not require ionizing radiation. US is commonly used to examine the size, and structure of the thyroid gland. In clinical routine, thyroid imaging is usually performed by means of 2-D US. Conventional approaches for measuring the volume of the thyroid gland or its nodules may therefore be inaccurate due to the lack of 3-D information. This work reports a semi-automatic segmentation approach for the classification, and analysis of the thyroid gland based on 3-D US data. The images are scanned in 3-D, pre-processed, and segmented. Several pre-processing methods, and an extension of a commonly used geodesic active contour level set formulation are discussed in detail. The results obtained by this approach are compared to manual interactive segmentations by a medical expert in five representative patients. Our work proposes a novel framework for the volumetric quantification of thyroid gland lobes, which may also be expanded to other parenchymatous organs.

Changes in the volume and length of the medial gastrocnemius after surgical recession in children with spastic diplegic cerebral palsy

BACKGROUND

Morphology is an important determinant of muscle force and power generation. Children with spastic diplegic cerebral palsy (SDCP) have reduced muscular strength, which in part is caused by inadequate muscle growth. There is a widespread concern that surgery to correct soft tissue deformities may exacerbate the underlying muscle weakness and further retard muscle growth. In this study, we compared measurements of medial gastrocnemius (MG) muscle morphology in typically developing (TD) children to those in children with SDCP with calf muscle deformities before and after corrective surgery.

METHODS

We measured the length and volume of the MG muscle belly using 3-dimensional ultrasound immediately before and at 7 weeks and 1 year after vulpius procedure (VP) surgery in children with SDCP. We made similar measurements in a group of TD children. The SDCP group consisted of 7 children (6 boys, 1 girls; total of 8 limbs; age range, 6-10 years; mean 8 years 1 month, SD +/- 1 year 11 months) and the TD group consisted of 10 children (4 boys, 6 girls; age range, 6-12 years; mean, 9 years 5 months; SD +/- 2 years 6 months).

RESULTS

The children with SDCP presented with MG muscle bellies both smaller and shorter than the TD children even when normalized to body mass and limb length, respectively. Muscle belly length was reduced by surgery and remained unaltered 1 year later, despite skeletal growth. Muscle volume was not significantly changed 7 weeks after surgery, but increased significantly between 7 weeks and 1 year after surgery.

CONCLUSIONS

Children with SDCP presented with short and small MG when compared with TD children. Our results indicate that gastrocnemius muscle volume recovers within a year of VP surgery.

CLINICAL RELEVANCE

This study is the first to investigate the effects of surgery on muscle belly volume and length in the human subject. The study indicates that VP surgery is not an agent of long-term muscle atrophy in individuals with SDCP with plantarflexion deformities.

Two-dimensional ultrasound measurement of thyroid gland volume: a new equation with higher correlation with 3-D ultrasound measurement

This study aimed to develop a new two-dimensional (2-D) ultrasound thyroid volume estimation equation using three-dimensional (3-D) ultrasound as the standard of reference, and to compare the thyroid volume estimation accuracy of the new equation with three previously reported equations. 2-D and 3-D ultrasound examinations of the thyroid gland were performed in 150 subjects with normal serum thyrotropin (TSH, thyroid-stimulating hormone) and free thyroxine (fT4) levels (63 men and 87 women, age range: 17 to 71 y). In each subject, the volume of both thyroid lobes was measured by 3-D ultrasound. On 2-D ultrasound, the craniocaudal (CC), lateromedial (LM) and anteroposterior (AP) dimensions of the thyroid lobes were measured. The equation was derived by correlating the volume of the thyroid lobes measured with 3-D ultrasound and the product of the three dimensions measured with 2-D ultrasound using linear regression analysis, in 75 subjects without thyroid nodule. The accuracy of thyroid volume estimation of the new equation and the three previously reported equations was evaluated and compared in another 75 subjects (without thyroid nodule, n = 30; with thyroid nodule, n = 45). It is suggested that volume of thyroid lobe may be estimated as: volume of thyroid lobe = 0.38.(CC.LM.AP) + 1.76. Result showed that the new equation (16.9% to 36.1%) had a significantly smaller thyroid volume estimation error than the previously reported equations (20.8% to 54.9%) (p < 0.05). There was a significantly larger thyroid volume estimation error when thyroid glands with nodules were examined (p < 0.05). With the use of the appropriate thyroid volume equation, 2-D ultrasound can be a useful alternative in thyroid volume measurement when 3-D ultrasound is not available.

Ovarian volume measurements in mice with high-resolution ultrasonography

OBJECTIVE

The aim of our study was to evaluate the intraobserver and interobserver variability of ovarian volume measurements in mice with high-resolution 2-dimensional ultrasonography (2DUS) and 3-dimensional ultrasonography (3DUS).

METHODS

Ovaries of 10 nude mice were visualized with a small-animal ultrasound scanner and a 40-MHz probe. For each ovary, volume was measured 3 times by 2 independent readers using both 2DUS and 3DUS methods. The 2DUS method used a biplane ellipsoid model. The 3DUS method estimated the volume by integrating 10 to 12 parallel image planes of the ovary after semiautomated outlining of the boundaries. For each type of measurement, intraobserver and interobserver standard error of measurement (SEM) values and minimal detectable volume changes were calculated by analysis of variance.

RESULTS

Two-dimensional ultrasonography showed much poorer reproducibility, with higher absolute intraobserver and interobserver SEM values (0.50 and 0.61 mm3, respectively) than 3DUS (0.20 and 0.35 mm3; P < .01). Relative intraobserver and interobserver SEM values were also much higher for 2DUS (12.20% and 14.88%) than for 3DUS (5.12% and 8.97%; P < .01). The minimal volume changes that could be detected with a 95% confidence level in successive measurements by the same (or different) observers were 33.90% (41.22%) for 2DUS and 14.10% (24.87%) for 3DUS.

CONCLUSIONS

High-resolution 3DUS can provide a reliable tool for noninvasive, longitudinal ovarian volume measurements in mice.

The newly developed three-dimensional (3D) and two-dimensional (2D) thyroid ultrasound are strongly correlated, but 2D overestimates thyroid volume in the presence of nodules

The newly developed three-dimensional (3D) and two-dimensional (2D) thyroid ultrasound (US) were compared in assessing thyroid volume (TV) in 104 patients: 53 had an isolated thyroid nodule, 32 toxic diffuse goiter, 17 non-toxic multinodular goiter, 1 toxic multinodular goiter and 1 a toxic adenoma. A real-time Technos apparatus (Esaote SpA, Italy) with a 7,5 MHz linear transducer was used. The volume of thyroid lobes by 2D was calculated according to the ellipsoid formula. In the same session, TV by 3D US was calculated using a probe tracking system (in vivo ScanNT Esaote 3.4 MedCom. Darmasdt) and software to reconstruct 3D images, directly giving the lobe volume. There was a very good agreement between 2D and 3D, but in 94/208 lobes with nodular lesions 2D showed a 10% systematic overestimation compared to 3D, the percentage error being higher in lobes with lower volumes. A possible explanation for this result is the inadequacy of the ellipsoid formula in forecasting the correct lobe profile in the presence of nodules. This intrinsic defect of 2D US should be taken into account when evaluating TV in patients with nodular goiter.

Thyroid morphology and function in adults with untreated isolated growth hormone deficiency

OBJECTIVE

GH influences thyroid function and anatomy. Although goiter is frequent in acromegalic patients, the effects of GH deficiency (GHD) are difficult to assess, because hypopituitaric subjects who lack GH often also have a partial or complete deficit of TSH.

STUDY DESIGN

We studied thyroid morphology and serum levels of thyroid hormones in adult members of a large Brazilian kindred with untreated isolated GHD due to a homozygous mutation in the GHRH receptor gene (GHRHR; nine men and 15 women; GHD group) and compared them to subjects heterozygous for the same mutation (eight men and 10 women; HET group) and subjects homozygous for the wild-type allele [seven men and 11 women; control (CO) group].

RESULTS

GHD subjects had a smaller thyroid volume (TV) than HET and CO. The TV of the HET group was intermediate between those of the GHD and CO groups. When TV was corrected by body surface area, it remained smaller in the GHD and HET groups than in the CO group, but the difference between GHD and HET groups disappeared. The GHD group had lower serum T3 levels than the CO group and higher free T4 levels than HET and CO groups.

CONCLUSIONS

Individuals with severe untreated GHD due to a homozygous GHRHR mutation and heterozygous carriers of the same mutation have smaller TV than normal subjects, suggesting that GH has a permissive role in the growth of the thyroid gland. In addition, GHD subjects have reduced serum total T3 and increased serum free T4, suggesting a reduction in the function of the deiodinase system.

Gray-scale three-dimensional sonography of thyroid nodules: feasibility of the method and preliminary studies

The aim of the study was differential evaluation of new and classical sonographic features of benign thyroid nodules and thyroid cancer with three-dimensional gray-scale sonography and evaluation of the effectiveness of the thin-slice surface rendered images in comparison with multiplanar reformation (MPR) presentation. Fifty-four thyroid nodules were interactively evaluated with thin-slice smooth surface rendering: shape in the c-plane (parallel to the probe) and evaluation of echogenicity, margins and calcification/microcalcification-like echogenic foci in the a-plane (plane of the probe). Evaluation of the level of agreement in readers' interpretation and between sonographic techniques was performed using the kappa statistic. Surface rendering permitted visualization of the shape of the nodule in the c-plane in all cases, in contrast to only up to 48% of cases in MPR evaluation. Lobulated nodule shape in the c-plane was 82-100% sensitive and 47-53% specific in diagnosis of carcinoma. Surface rendered images showed more calcification/microcalcification-like echogenic foci than MPR ones. The level of agreement between the observers in the evaluation of features of thyroid nodules and the agreement between features of thyroid nodules on MPR and surface-rendered images showed at least moderate reproducibility (kappa>or=0.41). Three-dimensional thin-slice surface rendering sonography appears to be a feasible and effective method for thyroid nodule evaluation.

Three-dimensional ultrasound measurement of thyroid volume in asymptomatic male Chinese

This study was undertaken to determine the accuracy and reliability of volume measurements using 3-D ultrasound (US). Variation of thyroid gland volume with age in asymptomatic Chinese men was also investigated. Volumetric measurements of the phantoms and thyroid glands were performed with a commercially available US machine in conjunction with the 3-D SonoScan Pro workstation. Ten tissue phantoms with volumes of 1.5 to 6.5 mL were measured with 3-D US. A water displacement method was used to measure the actual volume of the phantoms. The measured volumes were compared to the actual volumes. Volumes were measured by four operators to investigate interobserver variation. Thyroid US examinations were performed in 38 asymptomatic male Chinese subjects ages 21 to 72 years. The subjects were categorized into four age groups. In each subject, the volume of the left and right lobes and the isthmus of the thyroid gland were measured with 3-D US, and any variation with age was evaluated. Results showed that the actual volume of the tissue phantoms was highly correlated with the volume measured by the four operators (r = 0.9912 to 0.9977, p < 0.05). Interobserver variation in the volumetric measurements of the tissue phantoms was not significant (ICC = 0.9861). The range of thyroid volume of the subjects was 8.81 to 17.25 mL (mean 12.78 +/- SD 2.483), and there was no significant difference in thyroid volume between subjects of different age groups (p > 0.05). 3-D US is an accurate and reliable method by which to measure thyroid volume.