Feasibility of Quantitative Tissue Characterization Using Novel Parameters Extracted From Photoacoustic Power Spectrum Considering Multiple Absorbers

2021 ◽  
pp. 016173462110550
Author(s):  
Nikita Rathi ◽  
Saugata Sinha ◽  
Bhargava Chinni ◽  
Vikram Dogra ◽  
Navalgund Rao

Frequency domain analysis of radio frequency signal is performed to differentiate between different tissue categories in terms of spectral parameters. However, due to complex relationship between the absorber size and spectral parameters, they cannot be used for quantitative tissue characterization. In an earlier study, we showed that using linear relationship between absorber size and two new spectral parameters namely number of lobes and average lobe width, absorber size can be successfully recovered from photoacoustic signal generated by single absorber. As actual biological tissue contains multiple absorbers, in this study we extended the application of these two new spectral parameters for computing absorber size from signals generated by multiple PA absorbers. We revisited our analytical model to establish two new linear relationships between the absorber radius and number of lobes as well as average lobe width considering multiple absorbers with bandlimited acquisition. A simulation study was performed to validate these linear relationships. A retrospective ex vivo study, in which the spectral parameters were computed using multiwavelength photoacoustic signals, was performed with freshly exercised thyroid specimens from 38 actual human patients undergoing thyroidectomy after having a diagnosis of suspected thyroid lesions. From statistical analysis it is shown that both the parameters were significantly different between malignant and non-malignant thyroid and malignant and normal thyroid tissue. Performance of the supervised classification with the computed spectral parameters showed that the extracted parameters could be successfully used to differentiate malignant thyroid tissue from normal thyroid tissue with reasonable degree of accuracy.

2001 ◽  
Vol 120 (5) ◽  
pp. A507-A507
Author(s):  
M BLAEKER ◽  
A WEERTH ◽  
L JONAS ◽  
M TOMETTEN ◽  
M SCHUTZ ◽  
...  

2021 ◽  
Author(s):  
Steven Raeymaeckers ◽  
Yannick De Brucker ◽  
Tim Vanderhasselt ◽  
Nico Buls ◽  
Johan De Mey

Abstract Background. 4DCT is a commonly performed examination in the management of primary hyperparathyroidism, combining three-dimensional imaging with enhancement over time as the fourth dimension. We propose a novel technique consisting of 16 different contrast phases, instead of three or four different phases. The main aim of this study was to see if this protocol allows for the detection of parathyroid adenomas within dose limits. Our secondary aim was examining the enhancement of parathyroid lesions over time.Methods. For this prospective study, we included 15 patients with primary hyperparathyroidism prior to surgery. We obtain a 4DCT with 16 different phases: an unenhanced phase followed by 11 consecutive arterial phases and 4 venous phases. Centered on the thyroid, continuous axial scanning is performed over a fixed 8cm or 16cm coverage volume after start of contrast administration.Results. In all patients an enlarged parathyroid can be demonstrated, mean lesion size is 13.6mm. Mean peak arterial peak enhancement for parathyroid lesions is 384 HU compared to 333 HU for the normal thyroid. No statistical difference could be found. Time to peak (TTP) is significantly earlier for parathyroid adenomas compared to normal thyroid tissue: 30.8s versus 32.3s (p value 0.008). Mean Slope of Increase (MSI) of the enhancement curve is significantly steeper compared to normal thyroid tissue: 29.8% versus 22.2% (p value 0.012). Mean dose length product was 890.7 mGy.cm with a calculated effective dose of 6.7 mSv.Conclusion. We propose a feasible 4DCT scanning-protocol for the detection of parathyroid adenomas. We manage to obtain a multitude of phases, allowing for a dynamic evaluation within an acceptable exposure range when compared to classic helical 4DCT. Our 4DCT protocol may allow for a better visualization of the pattern of enhancement of parathyroid lesions, as enhancement over time curves can be drawn. This way wash-in and wash-out of contrast in suspected lesions can be readily demonstrated. Motion artifacts are less problematic as multiple phases are available.


2020 ◽  
Vol 19 (1) ◽  
pp. 53-60
Author(s):  
N. P. Tkachuk ◽  
I. S. Davydenko

In spite of a considerable efficacy of conservative treatment of goiter, surgery remains the main method of treatment of such patients. Though, on the one hand, total thyroidectomy inevitably results in the development of postsurgical hypothyroidism, on the other hand – in case organ-saving surgery is performed the risk of postsurgical relapse arises. Modern morphological methods are directed to detection of oncological risk of nodular formations, and recommendations concerning an adequate volume of surgery taking into account probability of relapse are practically lacking. Therefore, the objective of the study was finding criteria of a relapsing risk by means of investigation of morphological peculiarities of the parenchymal-stromal correlations in the thyroid gland with recurrent nodular and primary nodular (multinodular) goiter without signs of functional disorders. In the course of the research according to the examined correlation parameters of the parenchyma and stroma various forms of nodular goiter were found to differ from the thyroid tissue without pathological changes by a number of parameters. In particular, specific weight of the parenchyma on an average increases reliably in the tissue of nodular goiter with its various variants in comparison with the thyroid gland without pathological changes. Together with the increase of the parenchymal specific weight in nodular goiter the amount of colloid on an average decreases, and a specific dependence on the kind of goiter is observed – colloid volume decreases from goiter with slow growth to goiter with quick growth, and it is the smallest with goiter relapse. Quantitative analysis of the goiter tissue stromal component demonstrates a considerable increase of its specific volume in comparison with normal thyroid tissue. Evaluation of changes of the morphometric parameters in the thyroid follicles found that in case of nodular goiter with slow growth the percentage of follicles with colloid is close to 100%. On an average it does not differ from that of the normal thyroid tissue. At the same time, in case of nodular goiter with quick growth the percentage of follicles with colloid decreases sharply, and in case of relapse it appears to be still less than that in nodular goiter with quick growth. Besides, with nodular goiter the diameter of follicles on an average increases in comparison with the normal thyroid tissue. In a number of cases it can be estimated as macrofollicular goiter. At the same time, the diameter of follicles is smaller in nodular goiter with quick growth. It is still less in case of goiter relapse. The size of follicles becomes sharply diverse in case of nodular goiter with slow growth, but it decreases in case of nodular goiter with quick growth and relapse. Consequently, recurrent nodular goiter is mostly similar to that of primary nodular goiter with a quick growth, though certain differences between them exist. The peculiarities found enable to suggest that nodular goiter with a quick growth possesses more chances for relapse.


2018 ◽  
Vol 38 (3) ◽  
Author(s):  
Bo Gao ◽  
Lingji Guo ◽  
Donglin Luo ◽  
Yan Jiang ◽  
Jianjie Zhao ◽  
...  

Thyroid cancer is the most common endocrine cancer, and has a high incidence of lymphatic metastasis. Vascular endothelial growth factor C (VEGFC) is essential for development of lymphatic vessels and lymphatic metastases during carcinogenesis. Steroid receptor coactivator-1 (SRC-1) interacts with nuclear receptors and transcription factors to promote tumor proliferation and metastasis. However, the correlation between SRC-1 and VEGFC levels in the lymphatic metastases of thyroid cancer remains unclear. We analyzed 20-paired specimens of thyroid cancer tissue and normal thyroid tissue and found increased levels of SRC-1 and VEGFC proteins in 13/20 and 15/20 thyroid cancer specimens, respectively, when compared with those levels in specimens of normal thyroid tissue. A high level of SRC-1 expression was positively correlated with VEGFC and lymphatic endothelial cell marker LYVE-1 expression. Papillary thyroid carcinoma cell line TPC-1 displayed high levels of SRC-1 and VEGFC expression and was selected for stable knockdown of SRC-1 in vitro. Inhibition of SRC-1 significantly reduced the VEGFC levels in TPC-1 cells. We found that SRC-1 binds to transcription factor NF-kB (p50/p65), and that this coactivation complex directly promoted VEGFC transcription, which could be abrogated by SRC-1 knockdown. Up-regulated NF-kB signaling was also confirmed in thyroid cancer tissues. In vivo studies showed that SRC-1 knockdown restricted tumor growth, reduced the numbers of LYVE-1-positive lymphatic vessels, and decreased the levels of VEGFC in tumor tissues. These results suggest a tumorigenic role for SRC-1 in thyroid cancer via its ability to regulate VEGFC expression.


1992 ◽  
Vol 185 (1) ◽  
pp. 330-334 ◽  
Author(s):  
R. Cohen ◽  
M.C. Delehaye ◽  
S. Minvielle ◽  
N. Segond ◽  
J. Taboulet ◽  
...  

1984 ◽  
Vol 16 (09) ◽  
pp. 504-505
Author(s):  
M. Solter ◽  
D. Tišlarić ◽  
M. Dominis ◽  
M. Sekso ◽  
B. Pegan ◽  
...  

2016 ◽  
Vol 70 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Matthias Pohl ◽  
Florian Grabellus ◽  
Karl Worm ◽  
Georg Arnold ◽  
Martin Walz ◽  
...  

AimsMany studies have previously reported a higher prevalence of papillary thyroid carcinomas (PTC) in patients with Graves' disease (GD). MicroRNAs (miRNAs) are small, non-coding RNAs that are upregulated in PTC compared with benign thyroid tissue. The objective of the study was to examine the miRNA expression of selected miRNAs that are known to be upregulated in PTC in patients with GD.MethodsParaffin embedded thyroid tissue from 159 patients with GD was screened for expression of the miRNAs 146b, 181b, 21, 221 and 222 by RT-PCR. The expression profiles of four normal thyroids, 50 PTCs without concomitant GD and 11 patients with untreated GD served as the controls.ResultsThe expression pattern of these miRNAs in patients with GD is intermediate between that of benign thyroid tissue (p<0.001) and PTC (in three out of five miRNAs, p<0.001). This corresponds to a 15-fold change for GD versus PTC, and a 31-fold change for GD versus normal thyroid tissue. The miRNA expression in 11 papillary microcarcinomas found in our study (a prevalence of 0.07) was not different from that in PTC samples from patients without GD for four of five miRNA types. Furthermore, we found a significant difference in the expression of miRNA 221/222 between treated and untreated GD tissue.ConclusionsIn conclusion, we found an intermediate expression of specific miRNAs in thyroid tissue from patients with GD that fell between the expression levels found in normal thyroid glands and PTC, which suggests a possible influence of certain miRNAs on developing PTC in patients with GD.


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