Keywords:
Metastases, Metabolic disorders, Cancer, Imaging sequences, Diagnostic procedure, Computer Applications-Detection, diagnosis, Ultrasound, MR, CT, Paediatric, Neuroradiology brain, Abdomen
Authors:
Y. Tachibana1, R. Kishimoto1, T. Omatsu1, S. Kandatsu2, A. Hasegawa1, M. Koto1, R. Takagi1, T. Obata1, H. Tsuji1; 1Chiba/JP, 2Chiba-Ken/JP
DOI:
10.1594/ecr2013/C-0959
Purpose
We compared shear wave velocity measurement (SWV: acquired as a part of acoustic radiation force impulse elastography) with apparent diffusion coefficient (ADC) acquired from MRI exam to assess its capability to differentiate between benign and metastatic lymph nodes,
and to estimate the histological background reflected in SWV.
Background:
Ultrasonography (US) and MRI are both often used to evaluate enlarged cervical lymph nodes to diagnose metastasis; however,
the former alone is insufficient both in sensitivity and specificity [1,2],
while the latter is time-consuming,
costly,
and labor-intensive,
making it rather inconvenient although it may provide some useful information [3].
Stiffness is one of the important findings of physical exams for suspected metastatic lymph nodes [4].
From this point of view,
SWV measurement (introduced below) was considered useful.
SWV:
SWV measurement is a new quantitative technique for measuring the elasticity of the object area as part of US exam [5,6].
The outline of the technique is illustrated in Figure 1.
The SWV quantitatively reflects tissue stiffness: faster SWV indicates stiffer structure.
Excitation and measurement could be achieved using the same probe that is attached to the patient’s body surface for the whole process.
The procedure is carried out in less than one second.
Fig. 1: Procedure of measuring shear wave velocity (SWV). Target region of excitation is mechanically excited by using short-duration acoustic pulses (orange) to generate small (1-10um) tissue displacements. The displacement results in shear wave propagation away from the region of excitation (blue). The velocity of this SWV could be calculated by tracking the displacement at each lateral location by US (green).
References: SIEMENS