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Multi-slice Computed Tomography (MSCT) Analysis of Nodules

Multi-slice Computer Tomography (MSCT) Analysis of Benign and Malignant Nodules in Patients With Chronic Lymphocytic Thyroiditis
Highlights
MSCT features is useful in differentiate the benign and malignant nodules in CLT patients.
MSCT is superior than plain CT scan in nodule diagnosis in CLT patients
MSCT may apply as an important diagnostic modality in the clinical practice.
Abstract
Objective: To assess the clinical significance of Multi-slice Computer Tomography(MSCT) by comparing the MSCT feature of benign and malignant nodules in patients with chronic lymphocytic thyroiditis(CLT).
Methods: MSCT findings, including the size, solid percentage, calcification, margin, capsule, anteroposterior–transverse ratio as well as the mode and the degree of enhancement of 137 thyroid nodules in 127 patients with CLT were retrospectively analyzed. Furthermore, the correlation between MSCT finding and pathological results, the differences of MSCT finding between benign and malignant nodules were also analyzed.
Results: The complete solid was found in 77.5% (31/40) of malignant nodules while 32 nodules of dominant cystic components were all benign (P<0.05). Compared with the benign nodules, the microcalcification and internal calcification were more frequently presented in the maglinant nodules (P<0.05). The MSCT features such as ill-defined margin, absence of capsule or incomplete capsule or homogeneous enhancement were more likely to present in the malignant nodules(P0.05).
Conclusions: MSCT features is useful in differentiate the benign and malignant nodules in CLT patients. MSCT may apply as an important diagnostic modality in the clinical practice.
Key Words: Multi-slice Computer Tomography (MSCT), benign and malignant nodules, chronic lymphocytic thyroiditis(CLT)
Introduction
Chronic lymphocytic thyroiditis(CLT), also known as Hashimoto thyroiditis, is the most common thyroiditis disease in the clinic with a typical clinical presentation of diffuse and infiltration of lymphocytes in the thyroid and the formation of lymphoid follicles.(1-2) In the past, surgery is rare used in CLT treatment because CLT is thought as a diffuse lesion. However, the nodules which formed due to CLT itself or with thyroid nodules are usually found in the patients. In China, about one third of the patients presented with nodules were treated with surgery, and the incidence of thyroid cancer is significantly higher in CLT patients than that in non-CLT patients.(3) The application of computer tomography(CT) is restricted in differentiating the thyroid nodules and diagnosing diffuse CLT and few reports is focus on the CT features of the CLT with nodules. (4) We reported here is about comparison analysis of the benign and malignant nodules in the patients with CLT using multi-slice computer tomography(MSCT) and tried to explore the different CT features between these two kind of nodules to expand the clinical value of the MSCT.
Subjects and methods
Subjects
A total of 127 patients who diagnosed with thyroid nodules by palpation or B-mode ultrasound from January 2005 to December 2013 were enrolled in the study. Patients were included in the study if their cytology samples were evaluated as CTL with benign or malignant nodules.All the patients were performed with MSCT plain and enhanced scan on the thyroid. The male/Female was 10/117. The median age was 52 yrs (range 19-77 yrs).
MSCT analysis
The patients were required to place in supine position with hyperextend neck. All CT scans were obtained using a MSCT scanner (LightspeedPro 32 CT; General Electric, Milwaukee, WI) with the following parameters: 2.5-mm section thickness and section slice, and 30-35 seconds scan delay at arterial phase while 50-60 seconds scan delay during parenchyma tissue. The scanning range was planned in a craniocaudal direction from the superior border of hyoid to aorta arch including the entire thyroid mass (mean coverage, 250 mm). Each patient received 100 mL of nonionic contrast material (iohexol [Omnipaque 300, GE Healthcare]) through an 18-gauge needle placed in a peripheral arm vein at a rate of 2.5-3 mL/s and dose of 1.5 mL/kg. Axial images were reconstructed at 1.25-mm increments at the end of the scan and then coronal section was reconstructed.
Image analysis
Double blind analysis was performed in all the CT images. The CT features was recorded as follow: (1) Solid vs. cystic percentage: Solid (More than 95% solid percentage), 50-95% Solid, Cystic(1-49% Solid); (2) Calcification: a Morphology: Micro(diameter?2 mm) or Macro(diameter>2 mm) or eggshell(arc-shaped or semi arc-shaped) or Mixed(coexist with multiple calcification focus), b position: internal or peripheral; (3)Margins: Well-defined or ill defined (4) Capsule: Intact or incomplete or unclear and none; (5) Enhancement : Complete cystic or homogeneous enhancement or heterogeneous enhancement;(6) Lesion size: Max dimension of the lesion (7) anteroposterior and transverse ratio (8) Enhancement degree: measure the net value of artery or venous phase of the lesion and used the plain scan as the reference value. The measurement of the CT value should avoid regions presented with cystic change, necrosis, calcification and vessels.
Statistical analysis
All the statistical analysis were performed with SPSS 17.0 software (Illinois, US). Chi square was used to assess on count data. Student t test was used for measurement data after homogeneity test of variance. P<0.05 was considered as statistical significant.
Results
Patient demography and pathological feature of the lesions
There were 10 males and 117 females in our study. The median age was 52 yrs (range 19-77 yrs). The male/Female ratio was 1:11.7.
A total of 40 cases of CLT with malignant nodules were observed. Among them, 26 with papillary cancer (Figure 1A-B)(One combined with microcarcinoma), 10 with microcarcinoma, 2 with medullary cancer (Figure 2A-B), and 1 with lymphoma (Figure 3A-B). Among 26 papillary cancer, 3 combined with follicular adenocarcinoma, 1 combined with medullary cancer and follicular adenocarcinoma, and 5 combined with microcarcinoma and follicular adenocarcinoma. In addition, 87 CLT with benign nodules were observed, including 63 cases of follicular adenocarcinoma (Figure 4A-B), 7 cases of nodules goiter (Figure 5A-B) and 17 cases of nodules hyperplasia (Figure 6A-B). One malignant and nine benign nodules were found in 10 malignant cases with bilateral resection and were divided into benign and malignant group, respectively. The max nodule among multiple nodules in the benign group was used for comparison of CT feature and pathology analysis. According to the above described rules, 97 nodules and 40 nodules were divided into benign and malignant group, respectively.
Comparison of Benign and Malignant Nodules Within CLT
The solid percentage, the morphology and position of the calcification, margins, capsule and enhancement between benign and malignant group showed significant difference (p0.05)(Table 1). Most of the nodules in malignant group showed solid constitute (31/40, 77.5%) and none of the nodules was cystic constitute. 33% of the cystic constitute was found in benign nodules(32/97). The calcification incidence in malignant group was 37.5%, 22.5% was micro calcification, 88.2% was internal calcification (Figure 2A). 21.6% calcification was found in benign nodules and 81.0% was located in margin of the nodules (Figure 5A). Most of the benign nodules have well-defined (76.3%) and intact capsule(63.9%)(Figure 4A). Most of the malignant nodules have ill-defined margin (75.0%), unclear (65.0%)(Figure 2A) or incomplete(27.5%) capsule and 7 of them presented features of incomplete enhanced ring (Figure 1A). Among the heterogeneous benign nodules, 16 were peninsula enhancement which has irregular low density area in the periphery region or obvious enhanced nodules in the central region. While 7 in the malignant group presented with peninsula enhancement. No significant difference was found between benign and malignant nodules (?2=0.020, p=0.886). Among the homogeneous nodules, the incidence of malignant nodules (55.0%) was significantly higher than the benign nodules (25.8%)(p0.05)(Table 2). The remaining 76 benign nodules and 37 malignant nodules (Above 21 nodules were excluded) were processed with plain CT scan on the parachyma tissue. And no significant difference was found on net value of artery or venous phase(p>0.05)(Table 2).
Discussion
CLT is a kind of autoimmune disease featured by thyroid antigen response and lymphocytes infiltration by T and B cells. It is firstly reported by Hashimoto in 1912 and also named as Hashimoto thyroiditis (HT). CLT often occurs in the female and most of the patients are middle-young people. The median age of the patients was 52 yrs and the Male/Female ratio was 1:11.7, which is consistent with previous description. Some of the studies showed that CLT is closely related with the primary thyroid lymphoma(5) and increased risk of papillary cancer and microcarcinoma can be found in CLT patients(6-7). Among the 74 cases of CLT with nodules, 28.4% were malignant (40/127) and most of them were papillary cancer (26/40, 65.0%) and microcarcinoma (11/40, 27.5%). Although the combination of ultrasound examination with serum assessment can improve the sensitivity and specificity in malignant thyroid diagnosis,(8) lacking of the sonographic features on prediction value with high sensitivity and high positive in thyroid makes it difficult to differentiate the CLT with nodules while the hyper-variability on serum examination and half of the CTL was misdiagnosed.(1-2) Thyroid biopsy with fine needle before operation is another examination to identify the thyroid carcinoma.(8-10) However, Yang et al conducted a trial enrolled with 1100 patients and found that only 75% of the specificity was found by thyroid biopsy. Recently, the application of MSCT in thyroid diagnosis leads to the improvement on both specificity and sensitivity in thyroid nodules characterization.(11-12)
Here, we found the size of benign nodules is significant larger than the malignant nodules and this was because the higher incidence of microcarcinoma(27.5%) and timely operation on the suspected carcinoma. The nodules in the malignant group were complete solid or solid dominant and no cystic was found. This is because homogeneous distribution of the cancer cells and the adequate blood supply could reduce the liquid necrosis. 33.0% of cystic were found in the benign group and this may be related with the hyaline degeneration, bleeding, necrosis and hematoma absorbing. Moon et al suggested the sonographic diagnosis showed a specificity of 91.4%-92.5% when anteroposterior and transverse ratio ?1. The explanation may because expansive growth in benign nodules while infiltration was found in malignant nodules. Here, we didn’t find a significant difference on CT analysis between benign and malignant nodules when anteroposterior and transverse ratio ?1. The different conclusion made by CT and ultrasound may due to the pressure will be added when performing the ultrasound examination. Most of the benign nodules were soft and easy to transform under the pressure, therefore, the anteroposterior and transverse ratio <1 could be conducted. Most of the malignant nodules were parachyma with hard property and the effect of pressure is minimal.
We also tried to identify whether the margin was well-defined and the capsule was intact. Compared with the normal thyroid nodules, lower density thyroids and inferior contrast were observed in the CLT patients due to the uptake of the iohexol. Therefore it is hard to distinguish the different using plain scan. And the enhanced scan in CLT patients can help to find out the nodules. The pathology base of thyroid nodules is the presence of hyperplasia change in epithelial constitute of the nodules or one or multiple nodules constituted by eosnophils; Cystic change in the nodules, cystic wall constituted by fibrous tissue, lymphocytes and infiltration of the lymphocytes with lymphatic follicle presented in the cystic wall and periphery tissue, combined with well- or ill-defined margin.(13) Since the adequate blood supply of CLT tissue and tissue adenocarcinoma was under stress, most of the nodules have intact capsule and well-defined margin, there is a low density intact ring presented as mosaic or halo sign.(14) The goiter is a disease of hyperplasia. The hyperplasia nodules are isolated by fibrous tissue due to long-term thyroid enlargement and the follicle hyperplasia. Also a large amount of colloid was found in the hyperplastic follicles and psudo-capsule can be found around the nodules. Plain CT scan can only produce ill-defined thyroid outline or uneven thickness and intact capsule while enhanced CT can produce well defined thyroid outline. Most of the malignant nodules had ill-defined margin (75.0%), absence of capsule or unclear capsule (65%), incomplete pseudo-capsule (27.5%) and presented with incomplete enhanced ring feature. The pathological basis of the ill-defined margin around the cancer tissue was due to infiltration growth, invasion, extracapsule extension of the tumor tissue to the surrounding adeno-tissue. Tan et al suggested peninsular like enhancement is one of the features in diagnosing thyroid papillary cancer.(15) We didn’t observe a significant difference between benign and malignant group. Irregular necrosis and remaining cancer tissues were presented in both thyroid papillary cancer and papillary like adenocarcinoma. Due to the adequate blood supply of CLT, the peninsular enhancement can be found on CT features.
The CT finding on CLT without nodule was symmetrical and diffused enhancement on the two lobes of the thyroid or more severe enhancement was presented on one lobe. The enhancement was midsize, homogeneous with significant decrease and the density is closed to soft tissue. No nodule image or calcification image was found in the thyroid. The enhanced scan showed a homogeneous enhancement. The secondary manifest of the CLT is chronic nodule lymphocytes thyroiditis, local lymphatic goiter or nodules formed by pseudo carcinoma. The combination of the CLT can be adenocarcinoma, nodular goiter, thyroid cancer and lymphatic carcinoma. No significant difference was found on the value of plain scan, net value of artery phase or venous phase in the CTL with benign or malignant nodules. We excluded 21 complete cystic change benign nodules and the nodules with parenchyma were included. Furthermore, 3 nodules with complete calcification were also excluded due to the inaccuracy of the measurement on this kind of nodules and error on the CT value. The increasing number of blood vessel and increased speed of blood flow in thyroid parenchyma of CLT patients are caused by autoimmune process. And the microvessel density (MVD) and vascular endothelial growth factor (VEGF) were involved in this process. (16) Since the lymphocytes infiltration is present in the benign and malignant nodules and CLT with malignant tumor is derived from CLT hyperplasia, there is a transition between CLT and papillary cancer. Therefore, there is overlap on plain and enhance scan on the CLT with benign and malignant nodules.
In conclusion, the MSCT features in CLT with benign and malignant nodules are similar to simple benign and malignant nodules in thyroid. Due to the pathological feature of the CLT, there is some minor difference. In the CLT with parenchyma nodule, most of the malignant nodules are presented with solid, ill-defined margin, unclear or no capsule. The calcification is also usually seen, especially the micro grain calcification and most of the lesions are located in the center. The benign nodules are presented with cystic constitute, well-defined multiple margin, intact capsule and rare happened calcification (Located in the periphery region if presence). The enhancement degree of the parenchyma has no obvious value in differentiating the benign and malignant nodules.

The Future for Clinical Immunology

The last ten years has seen a tremendous increase in our understanding of the molecular basis of different disorders. Clinical immunology is a specialism which is currently developing in different ways, some of which are highlighted here. This discipline has a responsibility to provide a complete array of analytical measurements for the diagnosis and treatment of patients with dysfunction of the cellular and humoral immune system. Immunologists are working towards novel approaches to therapy in clinical immunology and the future is promising. The driver is to find less invasive means of diagnosis and treatment for life-threatening disorders and to improve patient morbidity and mortality.
Early diagnosis of cancer
According to epidemiological studies pancreatic cancer is the fourth leading cause of cancer-related death and the tenth most commonly diagnosed cancer in the United States. Exocrine tumors are the most frequent type of pancreatic cancer where pancreatic ductal adenocarcinoma (PDAC) accounts for 80 percent of malignant tumors of the pancreas. Most patients with pancreatic cancer present with advanced stage disease because patients with early-stage pancreatic cancer frequently do not have symptoms. Distribution of this tumor to distant sites in early stages with lack of effective markers for initial diagnosis and ineffective treatments for later stages of this tumor result in a poor prognosis for patients with pancreatic cancer. Within five years, prognosis for this disorder could be improved by discovering a way to detect microRNA biomarkers in blood for an early diagnosis of this disorder which will result in increased survival rate of patients.
Treatment of Cancer
About 50 percent of human malignancies are known to be due to mutations in the TP53 gene leading to alterations in p53 protein which makes the latter a potential target for cancer immunotherapy. It has already been found that adoptive transfer with p53-specific CD4 T-helper and cytotoxic T – lymphocytes (CTL) eliminate p53 over-expressing tumors in mice. p53 is immunogenic as antibodies and specific CTLs can be detected in cancer patients. Based on this, clinical trials were initiated to review the clinical and immunological response of p53-vaccines for immunotherapeutic treatment of cancer patients. Different vaccination strategies varying from dendritic cells, short- and long- peptide fragments and viral vectors have been used. The results from initial clinical trials were disappointing. There is a need to improve the immunogenicity of the above potentiators by enhancing the robustness of the induced effector T-cell responses or by simultaneously targeting additional tumor antigens. It is highly likely that in future the addition of multiple antigens to p53-vacinne will make it applicable in many cancer patients.
Disease markers in Breath
Human breath contains over 200 different volatile organic compounds (VOCs). Some diseases, including cancer, are associated with an increase in oxidative stress which generates a specific pattern of VOCs in the breath, known as the breath methylated alkane contour (BMAC). Changes in the BMAC are unique to different diseases allowing the potential identification of disease via the breath. Menssana Research has developed a BreathLink testing system for early diagnosis of breast cancer from the collection and analysis of VOCs. Together with gene profiling this could help detect otherwise asymptotic tumors.
Cell-free Circulating DNA
Cell-free circulating DNA (cf-DNA) has been reported as a biomarker in acute cardiovascular pathologies and as a mortality predictor in myocardial infarction. Jylhava et al. (2014) investigated whether the baseline cf-DNA concentration could indicate increased levels of early atherosclerosis and cardiovascular risk. The study population consisted of 1337 participants (aged 46–77 years) in the Health 2000 Survey. cf-DNA was quantified directly in plasma using the fluorescence-based Quant-iT™ high-sensitivity DNA assay kit. Increased cf-DNA levels paralleled a group of cardiometabolic risk factors, such as high blood pressure, unfavorable lipid metabolism profile and systemic inflammation in both sexes. In addition, higher cf-DNA levels indicated decreased arterial elasticity and glucose intolerance in women not using hormonal replacement therapy (HRT). The cf-DNA level was also observed to be an independent determinant for Young’s elastic modulus but not for carotid artery compliance or beta stiffness index in the women not using HRT. Hence, it was concluded that cf-DNA could serve as an auxiliary biomarker in cardiometabolic risk assessment and as an indicator of arterial stiffness in women not using HRT.
Brain Tumour Markers
Glioblastoma (GBM) is the most common malignant primary brain tumor. Present treatment options for this tumor include chemotherapy, radiation and surgical resection. Its clinical outcome is poor due to its existence in the body which makes it difficult in imaging. Magnetic resonance imaging is generally utilized to follow patients for tumor recurrence but it is challenging for a neurologist to distinguish between tumor regrowth and treatment effect. Therefore, clinical decisions frequently require a tissue diagnosis by means of surgical biopsy. A major disadvantage of biopsies is that they give an inaccurate picture of the presence of tumor due to inherent heterogeneity. The complex pathophysiology of brain tumors joined with a requirement for improved markers of prognosis and therapy response emphasize the necessity for clinically useful biomarkers that would exactly reveal the complete tumor.
Recently published research (2012) has revealed a microarray-based technology called ‘immunosignaturing’. By using this technology the type of disease could be established, normally before symptoms were manifest, by capturing the dynamics of circulating antibodies. Antibodies are good biomarkers because of their abundance, high affinity and specificity to their complementary antigen (epitopes), and they have high stability in serum. The benefit to the technique that Stafford employed is that it is inexpensive, simple, and highly sensitive to alterations in the antibody repertoire. Immune surveillance happens constantly and is fairly sensitive to changes in circulating proteins, for example, the introduction of cancer-specific chimeras such as BCR-ABL.From previous findings it is known that cancer cells elicit a detectable humoral immune response. According to Stafford et al, 2012., the precise antigens that may elicit an immune response in gliomas is not known therefore Stafford et al produced a single-use microarray which consisted 10,000 diverse random peptides in order to determine the pattern of antibody binding instead of examining single antibodies to a cancer antigen. These microarrays provide information about partial binding therefore by changing the length of time that an antibody is given to interact with these random peptides. A great deal of kinetic and thermodynamic information can be obtained. That is how Stafford et al. 2012 classified blinded glioma patient samples into precise groups that matched the tumor pathology and a molecular biomarker, MGMT promoter methylation. In the future this technique could be utilized to differentiate treatment efficacy and tumor recurrence.
Dengue Virus and Immuno-Inflammatory Pathologies
According to an epidemiological study by the World Health Organization about 50 million people get infected by dengue virus and around 2.5 million people are at risk. Severe dengue fever can manifest as dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS) with complex complications. There are three known immune components that interact with each other to produce DHF/DSS. This virus first contaminates immature dendritic cells via the mediation of dendritic cell specific intercellular adhesion molecule-3 (ICAM-3) binding to non-integrins which result in production of cytokines and metalloproteases.This, in turn, leads to activation of T-cells which result in activation of effector cells and leakage from blood vessels.Antibody enhancement is facilitated by Fc receptors that are found on the cell surface membrane of mature dendritic cells. Antibodies effect the replication of dengue virus – antibodies to viral epitopes cross react with a cell protein which results in production of cytokines and anaphylatoxins due to activation of CD8 effector cells.Anaphylatoxins are generated in two ways – through viral proteins or by forming an antibody-complement complex. The anaphylatoxins result in the altered activity of T-cells and hence to the pathogenesis of dengue virus fever.
There are very few constituents of the immune system that are unaffected by viruses. There are many unanswered questions on the spread of viruses. Such research will not only impact on the hemorrhagic viruses, but HIV, and the masters of disguise, the influenza viruses.
Gene Therapy
There will be further substantial advances in gene therapy. Not only will new genes be identified, but new techniques to modify or ablate their expression will be identified. These will target all levels of the genomic translation cascade, from DNA to protein. Genomics and proteomics will interface here. The greatest potential will arise from the identification of genes that either cause disease or lead to a susceptibility to disease. The expression of such genes is already achievable in experimental animals, and it is only a matter of time before this technology can be introduced into humans. For example, gene therapy has been effectively utilized to express chimerical antigen receptors (CARs) which give T cells their ability to identify tumor-associated antigens without the necessity for presentation by the MHC complex. Recent research by Singh, et al, 2013 made an attempt to modify the sleeping beauty (SB) gene system to lower manufacturing costs linked with transducing T-cells with recombinant viral vectors.
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