Correlation CEUS & Sono Elastography for Malignant Thyroid Nodule Evaluation N Kumaran MD, Md Ameen MD ULTRASOUND Department Of Radiodiagnosis, Velammal Teaching Hospital, MaduralTuticorin Ring Road, Anupandi, Madurai 625 009,Tamil Nadu, India Objective The aim was to study the patterns of solitary thyroid nodule with real time contrast enhanced ultrasound & sono elastography in establishing malignant thyroid nodule Materials & Methods 9 cases are presented ( 4 men & 5 women) for whom FNAC or CT neck with established nodal metastasis workup done. Degree of enhancement, process of enhancement, homogeneity of enhancement, surface of enhanced lesions versus strain & shear wave elastography Q box correlation done for solitary lesions. Results malignant or established higher staging primary in CT. The shape of most lesions in contrast ultrasound was irregular ( 94.59%), the boundary was however unclear ( 86.49%), inhomogenity ( 78.38%). Mean elasticity ratio varied with tumour grade and staging. Keywords Thyroid, contrast enhanced ultrasound, strain and shear wave elastography, enhancement characterstics, Q box and mean statistics elastography correlation, tumour grade. 17
Introduction Despite medical and socioeconomic advances in thyroid cancer screening for past 3 decades, thyroid cancer is one most commonly detected cancer women in India. Various literature discuss several factors that determine tumour prognosis like tumour size in ultrasound, CEUS ( contrast enahanced ultrasound), and elastography. Some of which include tumour size, morphology & internal characterstics. Currently FNAC however invasive method remains gold standard roid nodule inspite of recent advances in thyroid sonography. Moreover last 1 decade, new sonographic technique elastography developed. This technique and standard mean value also given for malignat versus benign also shown that elastography of entiate benign and malignant thyroid lesions with higher senprospective study, shear elastography reported 99 % sensitivity tiating benign versus malignant thyroid nodule lesions. In many reviews from literature, it was also noted tumour length on elastography to the length of the lesion on B mode imaging ( the elasticity imaging/ B mode ratio) was larger for aggressive tumours like anaplastic types. Previous studies have also demonstrated the feasibility of contrast enahcned ultrasonogof benign and malignant thyroid nodules. In one of the previous study, CEUS demonstrated 84.8% and accuracy of 82.6%. Quanantitative analysis of CEUS using micro bubble contrast of benign and malignant thyroid nodules and may contribute and potentially serve, in addition to grey scale and Doppler ultrasound, as an adjunctive tool in assessment of patients with thyroid nodules. Horunung et al reported CEUS reported CEUS, a highly sensitive method for detection of microvascularization of thyroid carcinoma. There was also study reported that contrast enhancement ultrasound patand malignant lesions. Ring enhancement predictive of beingn lesions, whereas heterogenous enhancement was helpful for detecting malignant lesions. There is certain limitations that even in present scenario, FNAC remains gold standard inspite of GRADES Degree Method Complete Boundary Shape PAPILLARY Centri Complete Regular Regular FOLLICULAR Concent Complete Regular Regular METASTASIS Centrip Incomplete Irregular Irregular ANAPLASTIC Central Centri Incomplete Irregular Irregular Table 1: 18
above mentioned recent advances sonographic techniques. Major lacunae in present decades, still overdependent on FNAC inspite of recent advances in sonographic techniques. Our study focused on malignant thyroid nodules worked up patients by FNAC proved or CECT with known nodal spread combined sonographic techniques of elastography and contrast enhanced ultrasound done to prove Probability Papillary Follicular Anaplastic Metastasis Sensitivity 98.38 98.38 94.59 97.47 95.12 95.37 94.74 98.67 PPV 93.55 91.40 97.08 97.63 NPV 97.11 91.09 96.09 90.24 Table 1: Combined diagnositv value of CEUS & sonoelastography technique in diagnosing & grading malignant nodules. Combined sonographic technique value added tool in detecting and grading malignant thyroid nodule with grey scale B mode ultrasound in future replacing FNAC. Moreover lacunae of FNAC for all the mass lesions of thyroid to be avoided. In best of my knowledge, FNAC contraindicated in bleeding disorders and thyroid AVM mass prone for excessive bleeding. In our experience, combined elastography & contrast enahanced ultrasound has proved extremely useful as a detecting and grading problem solving technique for malignant thyroid nodule and replacement in future for invasive FNAC in new cases. Materials & methods Study population consisted of 19 patients, either FNAC or CT workup done and established malignant nodule. Retrospectively evaluated for thyroid malignant sensitivity by contrast enhanced ultrasound and strain & shear elastography. Study population was approved by ethics committee of our hospital and patients informed consent was obtained. From January 2016 to april 2016, 09 patients with inclusion criteria of known thyroid malignancy included in the study. Minimum age 25 years and maximum age 55 years. Two experienced radiologist ( myself) of 11 years imaging along with two experienced female sonographers covered the study group. Moreover sonographers who prepared the patient for contrast ultrasonography were blinded. USG machine deployed is MINDRAY D5 colour Doppler unit with linear probe with frequency variability of 7.5 to 11 MHZ adjustable with minimal alteration in technical parameters. Initial thyroid nodule workup with done with non enhanced ultrasound. Patient neck was hyperextended and saggital & coronal planes nodule imaged.lesion characterstics, surface irregularity, size of the nodule, isthmus involvement & adjacent nodal involvement in cervical chain explored. Followed by Sonovue ( 25 mg) of lyophilized powder and 5 ml of 0.9% sodium chloride solution and mixed uniformly. Contrast injected through mostly brachial vein. The standard view of CEUS was the section which showed most abundant blood nodule lesion by power Doppler.Focus was adjusted also to trailing edge of lesion, and the gain was adjusted to display only the boundaries of the lesion. During the investigation, Position of the was asked to avoid swallowing and breath holding. The real time dynamic images were stored in the ultrasonic instrument. Real time CEUS of thyroid nodule persist only 3 minutes. The contrast enhancement patterns of the lesions were assessed in following methods as follows 1. Degree of enhancement ( lower or higher to surrounding gland) 2. Method of enhancement ( centripetal enhancement or non enhancement. 3.homogenous or inhomogenous type of enhancement. 4. Completeness of enhancement or incomplete 5. Boundary of enhanced lesions terns) and regular sonoelastogram technique done for all the 9 patients. The displacement needed for obtaining elastogram was provided by the patient breathing or cardiac rebound. If required, minimal manual compression/ decompression was used to obtain the elastogram. Images were dis 19
played side by side during a real time sonographic examination. Elasticity imaging/bmode ratios were obtained by dividing the axis of maximum dimension on the B mode image. Three measurements obtained from nodule of all patients, and the largest elasticity imaging/ Bmode ratio used.the highest ratio selected malignant potential in the thyroid nodule. A copy or shadow function was used to ensure that measurements were taken in the same location of the lesion. The greatest axis of maximum dimension of the lesion was measured on the Bmode image. Results Out of 9 patients, contrast enhancement pattern and elasticity/bmode ratio dated calculated aggressiveness and grades. FNAC out of 9 patients showed papillary 4, follicular 2 and meatstasis 2 and anaplatic in 1. Contrast enhacement pattern and sonoelastography results by statistical analysis were calculated by X2 test using statistical ence. In our experience, diagnostic value of contrast enhancement patterns of malignant thyroid sonoelastography ratio goes high in more aggressive malignant nodules. Moreover combined ( CEUS & sonoelastography) were extremely high with percentage of 94.3 % and 93.1 % respectively. Discussion Malignant nodules are the typical lesions which depend on blood vessels. Recently color Doppler and power Doppler have been most commonly used methods to detect blood vessels of tumour. Their larger blood vessels can be displayed by Doppler ultrasound, but micro vessels be shown. SonoVue is stabilized microbubble preparation with average diameter of 2.5 micrometre.microbubble can resonate at a low mechanical index. The microvascular perfusion of the tumour can be displayed clearly by using low energy Fig 1: CEUS patterns of enhancement without power Doppler Fig 2: Sonoelastography in compression technique for obtaining ratio in Q box Fig 3: CT workup in malignant thyroid nodule evaluation with nodal staging. 20
acoustic emission and pulse inversion harmonic imaging. CEUS has made a major improvements diagnosis of thyroid nodule. CEUS clearly depicted morphology of enhancement by aggressive nature of malignant nodules can be divided into three grades for discussion Grade 1 low to moderate variety with homogenous enhancement, regular margin and complete enhancement of nodules ( follicular grades Grade 2 moderate to high variety with inhomogenous enhacement, regular margin and 3/4th enhancement of nodules ( into this grades Grade 3 high degree of inhomogenous enhancement, irregular margin and incomplete enhancement of nodules ( into this grades In sonoelastography technique elasticity / B mode ratios classi sion FNAC proved aggressive tumours like metastasis and ana as degree of enhancement, homogeneity, completeness of enhancement, boundary of enhanced lesions. These contrast enhanced patterns contributed solitary malignant thyroid nodule. Likewise sonoelastography technique, elasticity/b mode ratio more than 1 and less than 1 corresponds to aggressive or moderate nature. By combining both advanced sonographic technique comprehensive diagnostic accuracy increased to higher level of sensitivity and in nodular thyroid lesion can become challenging as compared to present era where FNAC still gold standard. of interest Acknowledgment We are grateful to Velammal ul raphers for secretarial assistance References 1. 1.Rago T, Santini F, Scutari M, Pinchera A, Vitti P. Elastography: new developments in ultrasound for predicting malignancy in thyroid nodule. J clin endocrinol metab 2007;92:2917 2922 2. Averkious M, Powers J, Skyna D, Bruce M, Jensen S. Ultrasound contrast imaging research. Ultrasound Q 2003;19:2737 3. Mortensen JD, woolner LB, Bennett 1 in elasticity/b mode ratio clinically normal thyroid glands. J Clin Endocrinol Metab 1955:15:127080. score of less than 1 in elasticity/b mode ratio The study shown that combined CEUS and sonoelastography technique sensitivity and speci Conclusion chancement patterns of ma 4. Hegedius L. Clinical practice. The thyroid nodule. N Engl J Med 2004: 351:1764 71. 5. Zhang B, Jizang YX, Liu JB, Yang M, Dai Q, Zhu QL, et al. Utility of contrast enhanced ultrasound for evaluation of thyroid nodules. Thyroid 2010:20:5157 6. Jain RK. Normalizing tumour vasculature with anti angiogenic therapy: A new paradigm for combination therapy. Nat Med 2001;7:987989 21