A shear wave elastography role in differential diagnosis of the inflammatory pathology of lymph nodes in children

Abstract

Objective: to identify the opportunities of a shear wave elastography in the differential diagnosis of the inflammatory pathology of lymph nodes (LN) in children.
Materials and methods. A survey of 26 patients aged 4 to 17 years with the symptom-complex of node enlargement was performed. All patients were treated in the Surgical Department No.2 and the polyclinics of KMCH No.1, who themselves or their representatives (parents) voluntarily took part in the study. All participants were divided into 4 groups according to their clinical and laboratory parameters: children with reactive changes (lymphoid tissue hyperplasia) of the lymph nodes and acute viral infection in background (75% (6) that was confirmed clinically and radiologically) – 8 persons, children with acute serous lymphadenitis – 12, patients with purulent lymphadenitis – 6 and with specific lymphadenitis (Cat scratch disease or felinosis) – 2 persons. Localization of the pathological process was recorded in the lymph nodes of neck and maxillofacial area – 17 persons, axillary area – 8 and inguinal region – 3 patients. Ultrasound investigation was performed on the basis of the private office «Home doctor» in Kyiv on the Ultima PA sonograph (manufactured by the company «Radmir», Ukraine) with the function of a shear wave elastography using a linear probe L 3–12 MHz. The nature of lesions was determined by ultrasound assessment. Shape and size of LN, as well as a hilus nodi lymphatici were assessed. Nature of vascularisation was determined by color Doppler scanning. The particular attention during LN assessment was paid to elastography results. In case of heterogeneous structure of LN, measurement of stiffness in the kPa was performed. Stiffness (elasticity) on both intact and contralateral sides were estimated, but in case of homogeneous structure of LN the measurement was made only in one part.. We analysed colour flow mapping and quantitative assessment of tissue stiffness of LN (kPa). A standard range of colour scale was used in all cases – from dark blue (0 kPa) to bright red (60 kPa). Processing of the results was carried out using the «standart formulas» of MS Excel 2013.
Results. In case of reactive hyperplasia of LN the average stiffness was 8.55±0.58 kPa, in case of serous and purulent lymphadenitis – 18.68±3.87 kPa and 17.96±3.97 kPa, respectively. In 5 cases at the stage of serous inflammation (clinically) the anechoic lesions of LN that involved up to 20% of its total area were found, which was regarded as the initial stage of destructive suppurative changes. Such a conclusion was subsequent upon the data of the shear wave elastography that indicated the stiffness in the areas as 5.1±0,58 kPa, which corresponded to the indexes of the similar areas in purulent lymphadenitis (4.9±0.52 kPa). In general, the results of shear wave elastography showed that the average stiffness value of LN was similar in case of acute purulent and serous lymphadenitis. It was also noted that in case of cat-scratch disease, the average stiffness of affected LN was 21.69±0.88 kPa, while its value in anechoic areas made up 13.56±3.47 kPa, which indirectly considered as a possible necrotic zone with denser, destructive masses. This sign can be used in differential diagnosis of nonspecific and specific lymphadenitis.
Conclusions. 1). In case of reactive hyperplasia of LN the average stiffness was 8.55±0.58 kPa, but in case of serous and purulent lymphadenitis it made up 18.68±3.87 kPa and 17.96±3.97 kPa, respectively. 2). In case of the specific lesions (cat-scratch disease) the average stiffness of LN was 21.69±0.88 kPa, and 13.56±3.47 kPa, in their anechoic areas, which indirectly considered as a possible necrotic zone with denser, destructive masses. 3). The shear wave elastography using with ultrasound of LN greatly enhances the latter and allows to differentiate between reactive changes, acute inflammation and malignant lesions. Also it gives a possibility to clearly detect the initial manifestations of destructive changes on early stages of lymphadenitis, which affects the choice of treatment approach.