Change In Nodule Volume Research Articles

Assessing the relative effectiveness of various ultrasound-guided ablation techniques for treating benign thyroid nodules: A systematic review and network meta-analysis.

Benign thyroid nodules (BTNs) represent a prevalent clinical challenge globally, with various ultrasound-guided ablation techniques developed for their management. Despite the availability of these methods, a comprehensive evaluation to identify the most effective technique remains absent. This study endeavors to bridge this knowledge gap through a network meta-analysis (NMA), aiming to enhance the understanding of the comparative effectiveness of different ultrasound-guided ablation methods in treating BTNs. We comprehensively searched PubMed, Embase, Cochrane, Web of Science, Ovid, SCOPUS, and ProQuest for studies involving 16 ablation methods, control groups, and head-to-head trials. NMA was utilized to evaluate methods based on the percentage change in nodule volume, symptom score, and cosmetic score. This study is registered in INPLASY (registration number 202260061). Among 35 eligible studies involving 5655 patients, NMA indicated that RFA2 (radiofrequency ablation, 2 sessions) exhibited the best outcomes at 6 months for percentage change in BTN volume (SUCRA value 74.6), closely followed by RFA (SUCRA value 73.7). At 12 months, RFA was identified as the most effective (SUCRA value 81.3). Subgroup analysis showed RFA2 as the most effective for solid nodule volume reduction at 6 months (SUCRA value 75.6), and polidocanol ablation for cystic nodules (SUCRA value 66.5). Various ablation methods are effective in treating BTNs, with RFA showing notable advantages. RFA with 2 sessions is particularly optimal for solid BTNs, while polidocanol ablation stands out for cystic nodules.

The International Association for the Study of Lung Cancer Early Lung Imaging Confederation Open-Source Deep Learning and Quantitative Measurement Initiative

IntroductionWith global adoption of computed tomography (CT) lung cancer screening, there is increasing interest to use artificial intelligence (AI) deep learning methods to improve the clinical management process. To enable AI research using an open-source, cloud-based, globally distributed, screening CT imaging data set and computational environment that are compliant with the most stringent international privacy regulations that also protect the intellectual properties of researchers, the International Association for the Study of Lung Cancer sponsored development of the Early Lung Imaging Confederation (ELIC) resource in 2018. The objective of this report is to describe the updated capabilities of ELIC and illustrate how this resource can be used for clinically relevant AI research. MethodsIn this second phase of the initiative, metadata and screening CT scans from two time points were collected from 100 screening participants in seven countries. An automated deep learning AI lung segmentation algorithm, automated quantitative emphysema metrics, and a quantitative lung nodule volume measurement algorithm were run on these scans. ResultsA total of 1394 CTs were collected from 697 participants. The LAV950 quantitative emphysema metric was found to be potentially useful in distinguishing lung cancer from benign cases using a combined slice thickness more than or equal to 2.5 mm. Lung nodule volume change measurements had better sensitivity and specificity for classifying malignant from benign lung nodules when applied to solid lung nodules from high-quality CT scans. ConclusionsThese initial experiments revealed that ELIC can support deep learning AI and quantitative imaging analyses on diverse and globally distributed cloud-based data sets.

Benign thyroid nodules respond to a single administration of 0.3mg recombinant human thyrotropin with highly variable volume increase.

The nature of thyroid nodules is heterogenous. Most of them are benign and, in the absence of pressure symptoms of adjunct structures, no treatment is needed. Our objective was to investigate the acute effects of a low dose of recombinant human TSH (rhTSH) on the volume of benign thyroid nodules. we studied 27 nodules (14 isoechoic and 13 hypoechoic) in 15 (11 women and 4 men; mean age: 51.0 ± 15.9 years) consecutive patients with one to three well-separated asymptomatic benign thyroid nodules. All subjects were euthyroid, with negative thyroid antibodies, and none received levothyroxine. The total thyroid volume and thyroid nodule volume were sonographically determined by two independent examiners (P.B. and M.M.) before, 48 hours and 6 months post intramuscular (IM) administration of 0.3mg rhTSH, and the mean values of the two examiners' measurements were used; thyroid function tests were obtained at the same time points. The mean volume of isoechoic nodules increased by 57.3%, of hypoechoic nodules by 46.6% and of the surrounding thyroid parenchyma by 70.4% 48 hours post-rhTSH; mean volumes had returned to baseline levels 6 months later. A large variance in the volume change responses was observed. The relative change in nodule volume (defined as the percent change in nodule volume divided by the percent change in the surrounding parenchyma) from baseline to 48 hours was significantly higher in isoechoic versus hypoechoic nodules (p<0.05). A single dose of 0.3 mg rhTSH transiently increased the volume of benign thyroid nodules. The increase was more pronounced in isoechoic nodules and had a great variability. Our findings could be useful in the management of benign thyroid nodules, by helping in understanding which nodules would be more responsive to TSH suppression therapy.

Static and dynamic interaction between polyvinyl acetal brushes and flat surfaces—Measuring near-surface brush volume ratio and nodule volume change for moving brushes

The cleaning mechanism for brush scrubbing, known as the contact-type cleaning method, utilizes the direct contact of impurities onto brushes or brush-induced fluid flow depending on the contact condition. Applying brush cleaning to nanosized defects in advanced semiconductor manufacturing requires understanding of the interaction between the brush and scrubbing surface under actual operating conditions. We observed the near-surface brush volume ratio and brush nodule deformation using high-speed photography to obtain insights into efficient nanosized cleaning. Evanescent fields on a prism and a convex lens facilitate the definition of the observation depths of several hundred nanometers. Starting rotation experiments revealed a drastic reduction in the brush volume ratio, indicating that the static contact is far from the dynamic contact. The volume change during roller brush nodule deformation depends on the surface material. Furthermore, large friction materials exhibit large deformation and rapid recovery. These nodule deformations may generate a different fluid flow near the surface owing to the brush's fluid absorption and desorption.

Differentiation of Benign from Malignant Pulmonary Nodules by Using a Convolutional Neural Network to Determine Volume Change at Chest CT.

Background Deep learning may help to improve computer-aided detection of volume (CADv) measurement of pulmonary nodules at chest CT. Purpose To determine the efficacy of a deep learning method for improving CADv for measuring the solid and ground-glass opacity (GGO) volumes of a nodule, doubling time (DT), and the change in volume at chest CT. Materials and Methods From January 2014 to December 2016, patients with pulmonary nodules at CT were retrospectively reviewed. CADv without and with a convolutional neural network (CNN) automatically determined total nodule volume change per day and DT. Area under the curves (AUCs) on a per-nodule basis and diagnostic accuracy on a per-patient basis were compared among all indexes from CADv with and without CNN for differentiating benign from malignant nodules. Results The CNN training set was 294 nodules in 217 patients, the validation set was 41 nodules in 32 validation patients, and the test set was 290 nodules in 188 patients. A total of 170 patients had 290 nodules (mean size ± standard deviation, 11 mm ± 5; range, 4-29 mm) diagnosed as 132 malignant nodules and 158 benign nodules. There were 132 solid nodules (46%), 106 part-solid nodules (36%), and 52 ground-glass nodules (18%). The test set results showed that the diagnostic performance of the CNN with CADv for total nodule volume change per day was larger than DT of CADv with CNN (AUC, 0.94 [95% confidence interval {CI}: 0.90, 0.96] vs 0.67 [95% CI: 0.60, 0.74]; P < .001) and CADv without CNN (total nodule volume change per day: AUC, 0.69 [95% CI: 0.62, 0.75]; P < .001; DT: AUC, 0.58 [95% CI: 0.51, 0.65]; P < .001). The accuracy of total nodule volume change per day of CADv with CNN was significantly higher than that of CADv without CNN (P < .001) and DT of both methods (P < .001). Conclusion Convolutional neural network is useful for improving accuracy of computer-aided detection of volume measurement and nodule differentiation capability at CT for patients with pulmonary nodules. © RSNA, 2020 Online supplemental material is available for this article.

Surveillance of small, solid pulmonary nodules at digital chest tomosynthesis: data from a cohort of the pilot Swedish CArdioPulmonary bioImage Study (SCAPIS).

BackgroundDigital tomosynthesis (DTS) might be a low-dose/low-cost alternative to computed tomography (CT).PurposeTo investigate DTS relative to CT for surveillance of incidental, solid pulmonary nodules.Material and MethodsRecruited from a population study, 106 participants with indeterminate solid pulmonary nodules on CT underwent surveillance with concurrently performed CT and DTS. Nodule size on DTS was assessed by manual diameter measurements and semi-automatic nodule segmentations were independently performed on CT. Measurement agreement was analyzed according to Bland–Altman with 95% limits of agreement (LoA). Detection of nodule volume change > 25% by DTS in comparison to CT was evaluated with receiver operating characteristics (ROC).ResultsA total of 81 nodules (76%) were assessed as measurable on DTS by two independent observers. Inter- and intra-observer LoA regarding change in average diameter were ± 2 mm. Calculation of relative volume change on DTS resulted in wide inter- and intra-observer LoA in the order of ± 100% and ± 50%. Comparing relative volume change between DTS and CT resulted in LoA of –58% to 67%. The area under the ROC curve regarding the ability of DTS to detect volumetric changes > 25% on CT was 0.58 (95% confidence interval [CI] = 0.40–0.76) and 0.50 (95% CI = 0.35–0.66) for the two observers.ConclusionThe results of the present study show that measurement variability limits the agreement between DTS and CT regarding nodule size change for small solid nodules.

The effect of disease activity on thyroid nodules in patients with acromegaly.

Nodular thyroid disease is a very common disorder in patients with acromegaly. Insulin-like growth factor-1 (IGF-1) is a thyroid growth factor, and there is a correlation between IGF-1 levels and thyroid volume (TV) in patients with acromegaly. There is no study investigating the impact of somatostatin analog (SSA) treatment on thyroid nodule volume in patients with acromegaly. We aimed to assess thyroid nodule volume change with SSA treatment in patients with persistent acromegaly. We retrospectively analyzed data from 108 consecutive patients with acromegaly who were followed up by our clinic after undergoing surgery between 2002 and 2014. Patients who were cured after surgery were excluded. We only selected 43 patients (21 males, 22 females, mean age 52.8 ± 11.9 years) who did not meet the criteria of remission postoperatively, who were treated with SSA for at least six months and had normal thyroid function. Patients were divided into three groups (well-controlled, controlled, and active) according to their IGF-1 and growth hormone (GH) levels. All patients underwent an evaluation of TV and total thyroid nodule volume (TTNV) by ultrasound. TTNV decreased significantly in patients with well-controlled acromegaly (0.44 [0.75] to 0.23 [0.73], p < 0.001). TTNV did not change in controlled patients (0.18 [1.28] to 0.13 [1.54], p = 0.959); however TTNV increased in patients with active acromegaly (0.77 [1.46] to 1.03 [1.88], p = 0.028). Successful medical treatment of patients with active acromegaly decreases thyroid nodule volume. Sustained exposure to IGF-1 may cause an increase in thyroid nodule volume in patients with acromegaly.

Discrimination of Pulmonary Nodule Volume Change for Low- and High-contrast Tasks in a Phantom CT Study with Low-dose Protocols

The quantitative assessment of volumetric CT for discriminating small changes in nodule size has been under-examined. This phantom study examined the effect of imaging protocol, nodule size, and measurement method on volume-based change discrimination across low and high object to background contrast tasks. Eight spherical objects ranging in diameter from 5.0 mm to 5.75 mm and 8.0 mm to 8.75 mm with 0.25 mm increments were scanned within an anthropomorphic phantom with either foam-background (high-contrast task, ∼1000 HU object to background difference)) or gelatin-background (low-contrast task, ∼50 to 100 HU difference). Ten repeat acquisitions were collected for each protocol with varying exposures, reconstructed slice thicknesses and reconstruction kernels. Volume measurements were obtained using a matched-filter approach (MF) and a publicly available 3D segmentation-based tool (SB). Discrimination of nodule sizes was assessed using the area under the ROC curve (AUC). Using a low-dose (1.3 mGy), thin-slice (≤1.5 mm) protocol, changes of 0.25 mm in diameter were detected with AU = 1.0 for all baseline sizes for the high-contrast task regardless of measurement method. For the more challenging low-contrast task and same protocol, MF detected changes of 0.25 mm from baseline sizes ≥5.25 mm and volume changes ≥9.4% with AUC≥0.81 whereas corresponding results for SB were poor (AUC within 0.49-0.60). Performance for SB was improved, but still inconsistent, when exposure was increased to 4.4 mGy. The reliable discrimination of small changes in pulmonary nodule size with low-dose, thin-slice CT protocols suitable for lung cancer screening was dependent on the inter-related effects of nodule to background contrast and measurement method.

ES01.01 Image Quality Characteristics and Nodule Growth Measurement, Medical Physics and Machine Parameters

Modern CT scanners are routinely being used to determine the malignancy potential of small sub-centimeter pulmonary nodules. Increasingly, this involves CT scanning and quantitative volume measurement of lung nodules over short time intervals (e.g. 3 or 6 months) to determine whether a change in nodule size consistent with malignant growth has occurred. Although it may appear that current CT scanners are more than capable of reliably performing these quantitative measurements with high quality due to their ability to obtain sub-millimeter resolution lung images, many clinical sites are not taking the steps needed to achieve consistent high quality small lung nodule measurement results. A study of volume measurement performance in a phase II clinical trial observed multiple clinical sites using CT scanners which resulted in errors in volume change measurements as high as 43% [1]. In addition, a 2016 crowd-sourcing study of CT scanner image quality performance using the site’s low dose CT lung cancer screening acquisition protocol revealed that 37% of sites used insufficient slice thickness (<= 1.25mm slice thickness is needed) and only 19% of sites used the needed slice thickness and a reconstruction kernel that avoided excessive smoothing and avoided high levels of edge enhancement [2]. Poor CT image acquisition performance has the potential to result in poor lung nodule volume measurement performance which can negatively impact patient care by contributing to unnecessary biopsies and delays in early lung cancer diagnosis. To address these issues the RSNA’s Quantitative Imaging Biomarkers Alliance (QIBA®) has developed the QIBA CT Small Lung Nodule Profile that provides a comprehensive set of specifications to ensure that a clinical site attains a minimum level of quantitative imaging performance necessary to achieve a specified lung nodule volume measurement accuracy. The Small Lung Nodule Profile outlines six fundamental image quality characteristics that are needed throughout the full scanner field of view to support precise volumetric measurement of small lung nodules. These characteristics are (1) Edge Enhancement, (2) Three-Dimensional Resolution, (3) Resolution Aspect Ratio, (4) CT linearity, (5) Spatial Warping, and (6) Noise. In general, CT scanners achieve highest fundamental image quality performance at scanner iso-center with some scanners and image acquisition protocols exhibiting large losses in image quality performance as a function of distance from scanner iso-center [3]. These fundamental image quality properties can now be quickly and easily measured by a technologist at any clinical site using a new image quality measurement phantom and fully automated and cloud-based phantom analysis software. To determine the clinical impact of achieved CT image quality performance, a new set of modeling and simulation tools has been developed that can create simulated CT images given the image quality characteristics for a CT scanner and image acquisition protocol [4]. Quantitative measurement software can then be applied to these images resulting in expected measurement performance for a clinical task, such as the bias and precision of solid lung nodule volume change measurement for virtual lung nodules of different sizes. Having these estimates of a CT scanners performance can further be used to one day quantitatively determine the minimum time interval needed in order to be able to distinguish malignant nodule volume growth from a stable lung nodule. Regularly performing these measurements also has the potential to offer numerous advantages to lung cancer screening sites including the ability to determine if scans from two different CT scanner models will produce sufficiently similar image quality and measurement performance. In summary, a new set of phantoms and cloud-based software tools is available that enables more careful control and optimization of CT lung cancer imaging performance based on fundamental image quality properties. These new tools provide several new opportunities for clinical sites to more precisely perform CT lung cancer imaging studies and measurements. [1] Henschke CI, Yankelevitz DF, Yip R, Archer A, Zahlmann G, Krishnan K, Helba B, Avila R, “Tumor volume measurement error using computed tomography imaging in a phase II clinical trial in lung cancer.” Journal of Medical Imaging 3(3), 035505 (Jul–Sep 2016). [2] Avila R, Yankelevitz D, Yip R, Henschke C, “P1.03-021 Initial Results from A Novel and Low Cost Method For Measuring CT Image Quality,” January 2017. Journal of Thoracic Oncology 12(1):S554-S555. [3] Avila R, Subramaniam R, Henschke C, Yankelevitz D, “Hot Topic: Clinical Implications of CT Image Quality Variation in Low Dose Lung Cancer Screening Scans,” 4th World Congress of Thoracic Imaging Proceedings, Journal of Thoracic Imaging, accepted for oral presentation, 2017. [4] Avila R, Jirapatnakul A, Subramaniam R, Yankelevitz D, “A new method for predicting CT lung nodule volume measurement performance,” SPIE Medical Imaging Proceedings, 2017. "lung cancer screening", "Image Quality"

Semi-automated pulmonary nodule interval segmentation using the NLST data.

To study the variability in volume change estimates of pulmonary nodules due to segmentation approaches used across several algorithms and to evaluate these effects on the ability to predict nodule malignancy. We obtained 100 patient image datasets from the National Lung Screening Trial (NLST) that had a nodule detected on each of two consecutive low dose computed tomography (LDCT) scans, with an equal proportion of malignant and benign cases (50 malignant, 50 benign). Information about the nodule location for the cases was provided by a screen capture with a bounding box and its axial location was indicated. Five participating quantitative imaging network (QIN) institutions performed nodule segmentation using their preferred semi-automated algorithms with no manual correction; teams were allowed to provide additional manually corrected segmentations (analyzed separately). The teams were asked to provide segmentation masks for each nodule at both time points. From these masks, the volume was estimated for the nodule at each time point; the change in volume (absolute and percent change) across time points was estimated as well. We used the concordance correlation coefficient (CCC) to compare the similarity of computed nodule volumes (absolute and percent change) across algorithms. We used Logistic regression model on the change in volume (absolute change and percent change) of the nodules to predict the malignancy status, the area under the receiver operating characteristic curve (AUROC) and confidence intervals were reported. Because the size of nodules was expected to have a substantial effect on segmentation variability, analysis of change in volumes was stratified by lesion size, where lesions were grouped into those with a longest diameter of <8mm and those with longest diameter ≥8mm. We find that segmentation of the nodules shows substantial variability across algorithms, with the CCC ranging from 0.56 to 0.95 for change in volume (percent change in volume range was [0.15 to 0.86]) across the nodules. When examining nodules based on their longest diameter, we find the CCC had higher values for large nodules with a range of [0.54 to 0.93] among the algorithms, while percent change in volume was [0.3 to 0.95]. Compared to that of smaller nodules which had a range of [-0.0038 to 0.69] and percent change in volume was [-0.039 to 0.92]. The malignancy prediction results showed fairly consistent results across the institutions, the AUC using change in volume ranged from 0.65 to 0.89 (Percent change in volume was 0.64 to 0.86) for entire nodule range. Prediction improves for large nodule range (≥8mm) with AUC range 0.75 to 0.90 (percent change in volume was 0.74 to 0.92). Compared to smaller nodule range (<8mm) with AUC range 0.57 to 0.78 (percent change in volume was 0.59 to 0.77). We find there is a fairly high concordance in the size measurements for larger nodules (≥8mm) than the lower sizes (<8mm) across algorithms. We find the change in nodule volume (absolute and percent change) were consistent predictors of malignancy across institutions, despite using different segmentation algorithms. Using volume change estimates without corrections shows slightly lower predictability (for two teams).

High-Intensity Focused Ultrasound for Treatment of Symptomatic Benign Thyroid Nodules: A Prospective Study.

Purpose To evaluate first-year efficacy and changes in pressure symptoms and health-related quality of life (HRQOL) after ultrasonographically (US) guided high-intensity focused ultrasound (HIFU) ablation of symptomatic benign thyroid nodules. Materials and Methods After ethics approval and informed consent were obtained, a prospective trial was conducted. Patients with a symptomatic benign thyroid nodule were given a choice of HIFU treatment or active surveillance. Clinical and US examinations, pressure symptom scores (visual analog scale), and HRQOL questionnaires (short form-12 survey) were evaluated at baseline and at 3, 6, and 12 months. The primary outcome was change in nodule volume after 12 months. The percentage of change in nodule volume was defined as the baseline volume minus the volume at 12 months divided by the baseline volume times 100. Ablation success was defined as a reduction in volume of greater than 50%. Nodule volume was compared by using the paired t test. Continuous variables were compared by using the Mann-Whitney U test, and categorical variables were compared by using χ2 tests. Results Twenty-two patients underwent HIFU and 22 underwent active surveillance. Mean age was 53.11 years (range, 28-76 years) and 55.19 years (range, 41-70 years), respectively. The ratio of men to women was 2:20 and 1:21, respectively. The 12-month mean volume reduction ± standard deviation in the HIFU group was significant (68.87% ± 15.27 [range, 47.35%-94.89%], P < .001) but not in the surveillance group (-2.11% ± 6.29 [range, -15.64% to 12.70%], P > .05). Preablation nodule volume was the only determinant of ablation success (odds ratio, 1.877; 95% confidence interval [CI]: 1.085, 3.249; P = .024). At 12 months, patients in the HIFU group had less swelling (P < .001), lower pressure symptom scores (P < .001), and higher physical composite scores (P = .006). Physical composite scores significantly correlated with 6-month reduction in nodule size (r = 0.768; 95% CI: 0.660, 0.930; P < .001) and 12-month reduction in nodule size (r = 0.704; 95% CI: 0.680, 940; P < .001). Conclusion HIFU ablation of symptomatic benign thyroid nodules not only induced significant shrinkage but also improved pressure symptom scores and HRQOL throughout a 12-month period. © RSNA, 2017.

Single-Session High-Intensity Focused Ultrasound Treatment in Large-Sized Benign Thyroid Nodules.

High-intensity focused ultrasound (HIFU) is a new promising thermal ablation technique for treating benign thyroid nodules, but its effectiveness in larger-sized nodules has been less well described. The present study aimed to evaluate the treatment efficacy (i.e., extent of shrinkage at six months) of large-sized benign thyroid nodules by ultrasound (USG)-guided HIFU ablation. After ethics approval, all consecutive patients who underwent HIFU ablation of a symptomatic benign thyroid nodule with six or more months of follow-up were analyzed. Treated nodules were categorized according to their pre-ablation volume (group I: <10 mL; groups II: 10-30 mL; group III: >30 mL). After treatment, the nodule volume was measured by USG at one week, one month, three months, and six months. Total energy delivered to each nodule (in kJ) and the time taken (in minutes) for that delivery were automatically recorded. The primary outcome was a change in nodule volume after six months, where percentage nodule volume change was calculated as (baseline volume - volume at six months)/(baseline volume) × 100. Ablation success was defined as >50% volume reduction. Seventy-three nodules were treated successfully and followed for ≥6 months. The overall median six-month volume reduction was 68.3% (range 22.77-96.50%). At six months, group III had a significantly less volume shrinkage than group I (48.1% vs. 77.6%; p < 0.001) and group II (48.1% vs. 67.9%; p = 0.002). Also, the proportion of ablation success at six months in group III was significantly less than in the other two groups (p < 0.001). Pre-ablation nodule volume >30 mL (odds ratio = 7.813 [confidence interval 1.908-32.258]; p = 0.004) and lower total energy per nodule volume (odds ratio = 3.313 [confidence interval 1.113-9.688]; p = 0.029) were significant factors for less ablation success. Single-session HIFU ablation was highly effective in causing shrinkage of benign thyroid nodules at six months, but the extent of shrinkage for larger-sized nodules (>30 mL) was noticeably less than that of smaller-sized nodules. Both pre-ablation nodule volume and total energy per nodule volume were significant determinants of ablation success. For larger-sized nodules, additional HIFU treatment three to six months after initial treatment might be preferred over sequential treatment within the same session.

Percutaneous microwave ablation of type I substernal goiter under ultrasonic guidance

Objective To investigate the feasibility and clinical effect for percutaneous microwave ablation of type I substernal goiter under the guidance of ultrasound. Methods Thirteen patients with type I substernal goiter were selected. All patients underwent percutaneous microwave ablation treatment under the guidance of ultrasound. Thirteen patients with 47 medals nodules were performed ultrasound guided percutaneous microwave ablation. Intraoperativeheat blocking blood flowwas used to prevent severe hemorrhage.Liquid isolation beltandleverage frommethods were used to effectively prevent surrounding important structures against heat damage.Small amount of residual methodwas used to avoid tracheal collapse. All patients were followed up post-operative 1, 3, 6, 12 months by monitoring of thyroid nodule volume change, adverse reactions, and postoperative complications. Results Thirteen patients with 47 medals nodules were successfully performed percutaneous microwave ablation guided by ultrasound. Among them, 2 patients performed the second treatment for too large volume of goiter, tracheal displacement and poor physical tolerance of older. The postoperative ultrasound contrast and color Doppler showed that the lesions were completely inactivated. No obvious complications occurred in all 13 patients, and no permanent hoarseness occured. The symptoms of cervical oppression and discomfort disappeared for all patients within 1-4 months after surgery. Thirteen patients were followed up for 12 months after the operation. The thyroid function was normal and the volume reduction rate of thyroid nodules was (85±31)%. Conclusions Percutaneous microwave ablation of type I substernal goiter under ultrasonic guidance is a safe and effective method to reduce the thyroid nodules with no serious complications. It is worth to be popularized in clinical practice. Key words: Ultrasonography; Microwave/therapeutic use; Goiter, substernal

Minimum Detectable Change in Lung Nodule Volume in a Phantom CT Study

The change in volume of lung nodules is being examined as a measure of response to treatment. The aim ofthis study was to determine the minimum detectable change in nodule volume with the use of computed tomography. Four different layouts of synthetic nodules with different shapes but with the same size (5, 8, 9, or 10mm) for each layout were placed within an anthropomorphic phantom and scanned with a 16-detector-row computed tomography scanner using multiple imaging parameters. Nodule volume estimates were determined using a previously developed matched-filter estimator. Analysis of volume change was then conducted as a detection problem. For each nodule size, the pooled distribution of volume estimates was shifted by a percentage c to simulate a changing nodule, while accounting for standard deviation. The value of c resulting in a prespecified area under the receiver operating characteristic curve (AUC) was deemed the minimum detectable change for that AUC value. Both nodule size at baseline and choice of slice collimation protocol had an effect on the value of minimum detectable growth. For AUC=0.95, the minimum detectable nodule growth in volume when using the thin-slice collimation protocol (16×0.75mm) was 17%, 19%, and 15% for nodule sizes of 5, 8, and 9mm, respectively. Our results indicate that an approximate bound for detectable nodule growth in subcentimeter nodules may be relatively small, on the order of 20% or less in volume for a thin-slice CT acquisition protocol.

Changes in thyroid nodule volume caused by fine-needle aspiration: a factor complicating the interpretation of the effect of thyrotropin suppression on nodule size.

The effectiveness of TSH suppression therapy for thyroid nodules remains controversial. Prior studies have assumed that the fine-needle aspiration biopsy (FNAB), used to confirm a benign condition before the establishment of control and treatment groups, has no effect on nodule volume. Seventeen untreated euthyroid patients with clinical solitary thyroid nodules that were solid (on high-resolution ultrasound) and a colloid goiter (on cytologic examination) had ultrasound measurements of nodule volume before a FNAB, immediately thereafter, and 1 month and 6 months later. Size differences and individual variability at each time period were analyzed. No significant difference in mean thyroid nodule volume was present at any point after the FNAB; however, the changes in nodule volume were quite marked and bidirectional among patients masking the cumulative effect. The variability of the change in individual nodule volume was statistically significant when comparisons were made across time (P = 0.0032). FNAB of thyroid nodules results in significant individual changes in volume after the procedure. Studies, such as the effect of TSH suppression on thyroid nodule volume, that incorporate the FNAB in both control and treatment arms of the experimental design, need to take these changes into account, less erroneous conclusions result.

On the usefulness of levothyroxine suppressive therapy in the medical treatment of benign solitary, solid or predominantly solid, thyroid nodules

The efficacy of levothyroxine suppressive therapy in the treatment of benign solitary thyroid nodules is controversial. In order to investigate this issue further we studied 122 patients with a solitary, solid or predominantly solid, thyroid nodule. The benign (colloid) nature of all nodules was proved by fine-needle aspiration biopsy. At the pertechnetate-99m thyroid scanning 91% of the nodules were "cold" and 9% "warm". All the patients received suppressive oral doses of levothyroxine (0.1 to 0.2 mg/day). Fifty-three patients were treated with levothyroxine for 6 months, 31 for 9 months and 38 for 12 months. The size of each nodule before and after treatment was evaluated by high-resolution ultrasonography. The actual suppression of TSH secretion was monitored at 3-month intervals using an ultrasensitive immunometric assay. At the end of levothyroxine treatment, patients were classified as responders (decrease in nodule volume greater than or equal to 50%, 68/122 = 55.7%; mean percent change in nodule volume = -77.1 +/- 15.7%), partially responders (decrease in nodule volume less than 50%, 24/122 = 19.7%; mean percent change in nodule volume = -27.5 +/- 10.1%), and nonresponders, when either no change in nodule volume (16/122 = 13.1%) or an increase in nodule volume (14/122 = 11.5%) was observed. In each group serum free T4 rose significantly in response to levothyroxine therapy, whereas serum free T3 remained unchanged. TSH levels were undetectable in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)