In the general radiology practice, visual assessment of the SI loss is a commonly used method to characterize thymoma as well as adrenal adenoma and liver steatosis. The mean age of patients with thymoma was significantly higher than that of nonthymoma patients (47.9 ± 11.3 years vs 33.6 ± 11.8 years, P < .0001). A diagnosis of lymphocyte-rich thymoma was made based upon histological examination, positive pancytokeratin staining, variable lymphocyte CD3 expression and T cell receptor gamma polyclonality. The diagnostic ability of radiodensity and CSR for thymoma diagnosis was evaluated using the area under the receiver operating characteristic curve (AUROC). 1992;12 (1): 151-68. Such high reliability of chemical shift MRI in detecting fat in tissue and discriminating thymoma from nonthymoma in this study is similar to that of several studies.5,7,19. Observation was performed on soft tissue window W350, L100 HU. Pirronti et al6 showed the morphological criteria on CT to differentiate thymoma from hyperplasia. Although it can occur at any age, most patients are older than 40 years at the presentation. Chemical shift MRI demonstrated no signal intensity loss on the opposed-phase images relative to the in-phase images. In 49 patients, dual-echo technique in single breath hold was performed. Figure 1. I have read and accept the terms and conditions, View permissions information for this article. Meanwhile, the Se and Sp of radiodensity were 90.9% and 70.0%, respectively (using cutoff value of >18). A P value of <.05 was considered indicative of a statistically significant difference for all statistical analyses. The difference was observed in almost all assessed parameters, except for SI T1-weighted and SI T2-weighted. All quantitative CT parameters were significantly higher in patients with thymic cancer than thymoma (maximum axial diameter: 45 vs. 20 mm, maximum longitudinal diameter: 69 vs. 21 mm and volume: 77.91 vs. 4.52 mL; all P < 0.05). kept under surveillance with CT scans and chest X rays for years before requiring any treatment. PET/CT resulted positive in 15/17 patients with thymoma. However, this difference was negligible.3 Both Inaoka5 and Popa et al19 used CSR for studying despite one with non-dual-echo technique and one with dual-echo. In addition, non-dual-echo techniques were performed in 4 patients. For adrenal adenomas, Israel et al have reported such discordance in 7% (3 of 42) of cases in which the quantitative parameters have characterized a lipid-rich adenoma (CSR = 0.41-0.67 and SII = 36%-58%), but the qualitative analysis did not yield SI loss.21 Park et al also found the SI loss directly be observed was not sensitive than CSR measurement.22 In addition, for the assessment of hepatic steatosis, the studies have reported a lipid concentration threshold greater than 10% or 15% for detecting SI loss on the opposed-phase image relative to the in-phase image at visual assessment.23,24 Priola et al have reported 2 hyperplasia cases with the absence of SI loss, but SII was 7.8% and 12.7%, respectively.18 In this study, CSR was an important, independent criterion for differentiating thymoma from nonthymoma with an AUROC of 0.981. Logistic multivariate regression was performed by both predictive qualitative and quantitative variables to estimate the probability that patients had thymoma. Most thymic neoplasms arise in the epithelial cells of the thymus. David Johnson. Some society journals require you to create a personal profile, then activate your society account, You are adding the following journals to your email alerts, Did you struggle to get access to this article? At CT, the optimal cutoff point of 18 HU was used to differentiate thymoma from nonthymoma with Se, Sp, and Acc of 90.9%, 70%, 83%, respectively. show answer, A: Thymoma; teratoma;lymphoma and enlarged thyroid. Hood, MN, Ho, VB, Smirniotopoulos, JG, Szumowski, J. Priola, AM, Gned, D, Veltri, A, Priola, SM. The mean radiodensity was also higher in the thymoma group than in the nonthymoma group (34.45 ± 21.1 vs −4.65 ± 41.85, P < .001; Figure 1B). Computed Tomography and Magnetic Resonance Imaging Criteria for Thymoma and Nonthymoma. Logistic regression was used to identify the association between imaging parameters (eg, CSR) and the thymoma status. CT findings of thymoma were analysed in 58 patients who had undergone surgery between January 2002 and September 2007. A 22-year-old woman with TLH. Chemical shift imaging is much more sensitive to detect this fat by showing the SI loss in the opposed-phase image relative to the in-phase image.17 Conversely, thymomas have no fat and lack of SI loss. When combining both qualitative and quantitative parameters, MRI had even higher accuracy than did CT in thymoma diagnosis (P = .031). Basic lesion characterization with mediastinal MRI includes T1-weighted, T2-weighted, and pre-and post-dynamic contrast-enhanced (DCE) fat-saturated T1-weighted sequences. They are usually located anteriorly to the aortic arch but can occur in cardiophrenic angle. Figure 4. You can be signed in via any or all of the methods shown below at the same time. Download Full PDF Package. William Tester. Find out about Lean Library here, If you have access to journal via a society or associations, read the instructions below. The inclusion criteria were: (1) new onset of generalized MG, (2) definitive diagnosis based on postresection histological findings, and (3) being naive to neoadjuvant chemoradiotherapeutic treatment. The advantage of quantitative assessment is to use a threshold value for differentiating the lesions. Axial T1-weighted, T2-weighted and sagittal T2-weighted with fat suppression and black blood technique were added. Measurements were avoided in the areas of void signal at the interfaces between the fat-dominant and water-dominant tissues (India ink artifact).4 We also avoided measurements in cystic or necrotic components on the T2-weighted images (with and without fat suppression). Odds Ratio and Associated 95% Confident Intervals of Thymoma Diagnostic Probability According to Imaging Parameters. However no obvious bony erosion or chest wall involvement is noted. On CT, thymomas usually present as sharply demarcated round or oval soft tissue masses in the anterior mediastinum compartment.8 This typical appearance is highly suggestive of the diagnosis. Thymic carcinoma affects all age groups, but is more common in middle age and in older adults. In this table only specific protocols are summarized, since most institutions have their own standard protocols. It tends to grow and develop more quickly and is more likely to spread to other parts of the body. After completing this journal-based SA-CME activity, participants will be able to: 1. In 4 patients, non-dual-echo technique in separated breath holds was performed. It is helpful to work closely with MR technolo-gists using volunteers to optimize given pulse sequences and establish a working protocol. Ultrafast in- and opposed-phase chemical shift gradient echo (GRE) imaging is recommended for T1-weighted imaging because it provides a rapid means of T1-weighted imaging in a single breath-hold (~ 20 … 2. Patients progress after at least one previous line of platinum-based chemotherapy for advanced disease: a. 6 For MRI, since 1987, Batra et al demonstrated that MRI examination added no clinically important information to results obtained by CT in patients with MG. 15 However, at that time, MRI protocol included only T1-weighted and T2-weighted sequences. When a thymoma is suspected, a CT/CAT scan is generally performed to estimate the size and extent of the tumor, and the lesion is sampled with a CT-guided needle biopsy.Increased vascular enhancement on CT scans can be indicative of malignancy, as can be pleural deposits. The information on demographic and clinical characteristics of the patients was extracted from the participants’ medical records, while the information on imaging assessment (CT and MRI) of the patients was collected according to the imaging protocols given below. One hyperplasia case with absence of SI loss was correctly interpreted by CSR 0.68 (Figure 3). es from already established liver MR protocols and cardiac MR protocols at ones institution. PDF | BACKGROUND: Concomitant thymoma and T- lymphoblastic/leukaemia lymphoma is possible. As generalized MG was not a common disease in Vietnam, all eligible patients with MG were consecutively enrolled, except those who were under 16 years. In Pirronti et al’s study, the Se of CT for detecting hyperplasia was only 36%.6 For MRI, since 1987, Batra et al demonstrated that MRI examination added no clinically important information to results obtained by CT in patients with MG.15 However, at that time, MRI protocol included only T1-weighted and T2-weighted sequences. This product could help you, Accessing resources off campus can be a challenge. The respective odds ratio (95% confidence interval [95% CI]) for CSR and the shape was 8.80 (95% CI: 1.359-56.93) and 11.723 (95% CI: 1.332-103.202), respectively (Table 4). All participants provided written consent forms. Stages II-III: Complete surgical excision and postoperative radiotherapy is recommended to decrease the incidence of local recurrence 3. In our study, CST was applied because the non-dual-echo technique was used in four cases. In conclusion, chemical shift MRI was more accurate than CT for differentiating thymoma from nonthymoma in patients with MG. Myasthenia gravis (MG) is a relatively uncommon disease. The CSR was 0.92. The horizontal line inside the boxes is the median value. The presence of various CT findings was correlated with tumour invasiveness and recurrence. In Pirronti et al’s study, the Se of CT for detecting hyperplasia was only 36%. The AUROC of CSR and radiodensity in differentiating the 2 groups was 0.981 (95% CI: 0.899-1.000) and 0.798 (95% CI: 0.666-0.896), respectively (P < .05). Thymoma and Thymic Carcinoma Protocol applies to thymic epithelial tumors located in any area of the mediastinum. The lesion is anteriorly abutting the right mid costal cartilages and the sternum. The CSR was 0.68. Some normal or hyperplasia cases with no SI loss have been recently reported in the literature.3,25,26 With thymic hyperplasia cases without fat (Figure 5), Priola suggested that diffusion-weighted MRI could be valuable by demonstrating restricted diffusion and low apparent diffusion coefficient (ADC) values. Measurements were made in the central position and not in peripheral areas to avoid partial volume effects. treatment of thymoma in the cat > Incidence and epidemiology Thymoma is the most common thymic neoplasms that arises from thymic epithelial cells.1-9 Thymomas have been described in cattle, dogs, cats, sheep, goats, horses, pigs and rabbits.3,10 Thymoma and lymphoma represent the most common thymic neo-plasms in cats. Imaging parameters are listed in Table 1. The aim of the study was to evaluate the usefulness of computed tomography (CT) and magnetic resonance imaging (MRI) for differentiating thymoma from nonthymoma abnormalities in patients with myasthenia gravis (MG). After detecting a mass anterior to the compartment, diagnosticians could use PET-CT to differentiate thymic neoplasm from normal and hyperplastic tissues. Please read and accept the terms and conditions and check the box to generate a sharing link. The SI loss can be assessed qualitatively by direct observation and can be assessed quantitatively by calculating the index of CSR or SI index (SII). Patients with thymoma or thymic carcinoma who met specific criteria on computed tomography were accrued. Simply select your manager software from the list below and click on download. Chemical shift MRI demonstrated no signal intensity loss on the opposed-phase images relative to the in-phase images, suggesting the absence of fat component. The mean CSR was higher in the thymoma group than in the nonthymoma group (1.021 ± 0.068 vs 0.648 ± 0.109, P < .001; Figure 1A). For more information view the SAGE Journals Sharing page. Correspondence Laura Evangelista, Radiotherapy and Nuclear Medicine Unit, Istituto Oncologico Veneto IOV – IRCCS, Via Gattamelata, 64 35128 Padova, Italy. CSR indicates chemical shift ratio; CT, computed tomography; MRI, magnetic resonance imaging; TLH, thymic lymphoid hyperplasia. Stage I: Complete surgical excision is the treatment of choice for nonmetastatic thymoma and thymic carcinoma, even when the tumor is locally advanced 2. Over 30 conditions have been associated with thymomas 5. The incidence of thymoma in the United States is estimated to be 0.13 to 0.15 per 100,000 people. The email address and/or password entered does not match our records, please check and try again. The SI measurements within the thymus and chest wall muscle were obtained by using ROI (area, 0.5-1 cm2 for the thymus gland and 1-2 cm2 for the chest wall muscle), then were used for calculation of CSR. In order to measure the radiodensity, region of interest (ROI) was manually drawn at the level where the thymus appeared largest on the cross-sectional image, with exclusion of peripheral areas, calcifications, cystic, or necrotic components as well as beam-hardening artefacts. The cat was treated with 2 × 8 Gy intensity modulated radiation therapy and sulfoquinovosyl acyl propanediol (SQAP). A cross-sectional study of 53 patients with MG, who had undergone surgical thymectomy, was conducted at 103 Hospital (Hanoi, Vietnam) and Cho Ray Hospital (Ho Chi Minh City, Vietnam) during August 2014 and January 2017. Other commonly occurring tumors of the anterior mediastinum include lymphoma (25%), thyroid and parathyroid tumors (15%), benign teratoma (10%), malignant germ cell tumors (10%), and benign thymic lesions (5%) (4). Thoracic CT performed 35 days after the commencement of chemotherapy showed a marked reduction in the size of the mass, with an estimated volume of 9.4 cm3. PET should be added to the armamentarium as an available diagnostic modality to aid in staging and excluding … The authors are grateful to the study participants. A histopathologic image exhibits preserved architecture of the thymus, consisting of cortex, medulla, and Hassall corpuscles with lymphoid follicles and minimally fatty infiltrated thymic tissue. Experience has been reported as an important influencing factor in observation errors.20. Frontal view shows a soft tissue shadow silhouetting the right heart border. Their medical, medicine, and treatment history will be reviewed.