Multimodal photoacoustic/ultrasonic imaging system: a promising imaging method for the evaluation of disease activity in rheumatoid arthritis

Abstract

Objectives We aimed to assess the clinical value of multimodal photoacoustic/ultrasound (PA/US) articular imaging scores, a novel imaging method which can reflect the micro-vessels and oxygenation level of inflamed joints of rheumatoid arthritis (RA). Methods Seven small joints were examined by the PA/US imaging system. A 0–3 scoring system was used to semi-quantify the PA and power-Doppler (PD) signals, and the sums of PA and PD scores (PA-sum and PD-sum scores) of the seven joints were calculated. The relative oxygen saturation (SO2) values of the inflamed joints were measured and classified into 3 PA+SO2 patterns. The correlations between the PA/US imaging scores and the disease activity scores were assessed. Results Thirty-one patients of RA and a total of 217 joints were examined using the PA/US system. The PA-sum had high positive correlations with the standard clinical scores of RA (DAS28 [ESR] ρ = 0.754, DAS28 [CRP] ρ = 0.796, SDAI ρ = 0.836, CDAI ρ = 0.837, p < 0.001), which were superior to the PD-sum (DAS28 [ESR] ρ = 0.651, DAS28 [CRP] ρ = 0.676, SDAI ρ = 0.716, CDAI ρ = 0.709, p < 0.001). For the patients with high PA-sum scores, significant differences between hypoxia and hyperoxia were identified in pain visual analog score (p = 0.020) and patient’s global assessment (p = 0.026). The PA+SO2 patterns presented moderate and high correlation with PGA (ρ = 0.477, p = 0.0077) and VAS pain score (ρ = 0.717, p < 0.001). Conclusion The PA scores have significant correlations with standard clinical scores for RA, and the PA+SO2 patterns are also related with clinical scores that reflect pain severity. PA may have clinical potential in evaluating RA. Key Points • Multimodal photoacoustic/ultrasound imaging is a novel method to assess micro-vessels and oxygenation of local lesions. • Significant correlations between multimodal imaging parameters and clinical scores of RA patients were verified. • The multimodal PA/US system can provide objective imaging parameters, including PA scores of micro-vessels and relative SO2value, as a supplementary to disease activity evaluation.

Fluorescence, ultrasonic and photoacoustic imaging for analysis and diagnosis of diseases

“…[1][2][3][4][5] Since a growing body of evidence indicates the importance of bioimaging technology, numerous kinds of bioimaging technologies, such as computed tomography (CT), single photon emission CT (SPECT), positron emission tomography (PET), X-ray imaging, radiation imaging, Raman imaging, magnetic resonance imaging (MRI), fluorescence imaging, ultrasonic imaging and photoacoustic imaging, have been developed for the diagnosis and determination of diseases in the laboratory, and preclinical and clinical trials. [4][5][6][7][8][9][10][11][12] Among them, owing to its outstanding advantages of rapid and sensitive feedback, multiple signal acquisition capability, high temporal resolution, as well as maneuverable instruments, the non-invasive fluorescence imaging method has been employed as a powerful tool for labeling and tracing specific molecules, proteins and organelles in living cells and even whole animals, and is hence capable of imaging and monitoring different diseases, [13][14][15][16][17][18][19] such as ocular diseases, different bacterial infections, cancer and lymph node (LN) metastasis. Fluorescence imaging can also be utilized to guide surgery in the treatment of disease.…”

Photoacoustic/ultrasonic dual-mode imaging for monitoring angiogenesis and synovial erosion in rheumatoid arthritis

“…In addition, recent studies have addressed the use of exogenous PA contrast agents combined with drugs as the imaging or therapeutic medium for RA [29] , [46] , [47] . Currently, PAI is not only limited to animal models, and relevant imaging devices and techniques are already available in the clinic [48] , [49] , [50] . One study examined seven small joints in humans using a PA/US imaging system to measure relative oxygen saturation values in inflamed joints and showed that the sub-PA score was highly positively correlated with the standard clinical score for RA.…”

Dual-Wavelength Photoacoustic Computed Tomography with Piezoelectric Ring-Array Transducer for Imaging of Indocyanine Green Liposomes Aggregation in Tumors

“…In the PA imaging system, there are several common types of ultrasound transducers [10], such as single-element transducers [11], handheld linear transducers [12], and curve-array or ring-array transducers [7,[13][14][15]. Photoacoustic computed tomography (PACT), as a common form of PA imaging, has shown the excellent potential in clinical applications, including monitoring the circulating tumor cells [16], whole-body imaging for small animals [14], imaging for cancer and inflammation [13,14], therapy monitoring and molecular imaging [17].…”