BackgroundIndocyanine green (ICG)-enhanced fluorescence optical imaging (FOI) is an established technology for imaging of inflammation in animal models. In experimental models of arthritis, FOI findings corresponded to histologically proven synovitis. This is the first comparative study of FOI with other imaging modalities in humans with arthritis.Methods252 FOI examinations (Xiralite system, mivenion GmbH, Berlin, Germany; ICG bolus of 0.1 mg/kg/body weight, sequence of 360 images, one image per second) were compared with clinical examination (CE), ultrasonography (US) and MRI of patients with arthritis of the hands.ResultsIn an FOI sequence, three phases could be distinguished (P1–P3). With MRI as reference, FOI had a sensitivity of 76% and a specificity of 54%, while the specificity of phase 1 was 94%. FOI had agreement rates up to 88% versus CE, 64% versus greyscale US, 88% versus power Doppler US and 83% versus MRI, depending on the compared phase and parameter. FOI showed a higher rate of positive results compared to CE, US and MRI. In individual patients, FOI correlated significantly (p<0.05) with disease activity (Disease Activity Score 28, r=0.41), US (r=0.40) and RAMRIS (Rheumatoid Arthritis MRI Score) (r=0.56). FOI was normal in 97.8% of joints of controls.ConclusionICG-enhanced FOI is a new technology offering sensitive imaging detection of inflammatory changes in subjects with arthritis. FOI was more sensitive than CE and had good agreement with CE, US in power Doppler mode and MRI, while showing more positive results than these. An adequate interpretation of an FOI sequence requires a separate evaluation of all phases. For the detection of synovitis and tenosynovitis, FOI appears to be as informative as 1.5 T MRI and US.

Objective. Indocyanine green-enhanced fluorescence optical imaging (FOI) is a novel diagnostic tool for the assessment of inflammation in arthritis. We undertook this study to compare FOI with magnetic resonance imaging (MRI) in 32 patients with early and very early untreated arthritis (mean disease duration 7.1 months).Methods. FOI images were acquired with the commercially available Xiralite system. Image interpretation was done for an early phase (phase 1), an intermediate phase (phase 2), and a late phase (phase 3), and for an electronically generated composite image. The results were compared with those of clinical examination (960 joints) and contrast (gadolinium)-enhanced 1.5T MRI (382 joints) of the clinically more affected hand. Additionally, we evaluated FOI in a control group of 46 subjects without any signs of inflammatory joint disease (1,380 joints).Results. With MRI as the reference method, the sensitivity of FOI was 86% and the specificity was 63%, while the composite image, phase 1, and phase 3 reached high specificities (87%, 90%, and 88%, respectively). The results differed considerably between the composite image and the phases. FOI did not detect inflammation in 11 joint regions that showed palmar tenosynovitis on MRI. Intrareader and interreader agreements were moderate to substantial ( ‫؍‬ 0.55-0.73). In the control group, FOI showed positive findings in 5% of normal joints in phase 2.Conclusion. Further multicenter studies will address the question of whether FOI allows sensitive and reliable detection of inflammatory changes in early arthritis, as suggested by our initial findings. If this is confirmed, FOI has the potential to be a sensitive and valuable tool for monitoring disease activity on site in clinical settings and for serving as an outcome parameter in clinical trials.

To assess the utility of changes in the volume of the caudate lobe in the sonographic diagnosis of liver cirrhosis, the authors studied 58 patients with histologically proved cirrhosis, 18 patients with fatty liver, 28 patients with liver metastases, seven patients with lymphomatous liver involvement, and 75 healthy individuals. The longitudinal (CL), transverse (CT), and anteroposterior (CAP) diameters of the caudate lobe and the transverse diameter of the right lobe (RL) were measured, and one-, two-, and three-dimensional caudate lobe indexes and ratios were calculated. The analysis of the diagnostic performance of these criteria, compared by means of receiver-operating characteristic curves, revealed that the ratio of the three-dimensional caudate index (CI3) to the right lobe diameter (CI3/RL = [CL X CT X CAP]/RL) was superior to all other calculated criteria. At a specificity of 95%, the sensitivity of CI3/RL was 94.7%, compared with 73.3% for CT/RL. No significant differences were found between the control group and patients with fatty liver, metastases, or lymphomatous involvement. The study suggests that CI3/RL is the most reliable quantitative criterion for the US diagnosis of liver cirrhosis.

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To assess the efficacy of splenic size in the sonographic diagnosis of lymphomatous involvement of the spleen, the authors studied 31 patients with splenic lymphoma (Hodgkin's disease, 17 and non-Hodgkin's lymphoma, 14) and 218 individuals without evidence of splenic disease. All subjects were studied with both a linear and a sector transducer. The longitudinal, transverse and diagonal diameters of the spleen were measured, and two- and three-dimensional splenic indices were calculated. The analysis of the diagnostic performance of these criteria, compared by means of receiver-operating characteristic (ROC) curves, revealed that diagnosis of splenic involvement by malignant lymphoma was considerably more reliable with a sector than with a linear scanner. If the longitudinal diameter was measured with a sector scanner, sensitivities were 66% and 74%, at specificities of 95% and 90% respectively (cut-off points: 12.5 cm and 11.3 cm, respectively). For the sector scanner, there was no advantage in using other diameters or multidimensional indices. Additional ROC analysis of recently published data indicating excellent discrimination capacity of a computed tomography index revealed that these results were largely owing to patient selection. In contrast, our data suggest that the potential of current non-invasive assessment of splenic lymphoma is limited. However, ultrasound may eventually help to eliminate staging laparotomy in selected cases, e.g. in patients with low risk of abdominal disease and with increased surgical risk.