Abstract
BackgroundThe overlap of morphological feature and mean ADC value restricted clinical application of MRI in the differential diagnosis of orbital lymphoma and idiopathic orbital inflammatory pseudotumor (IOIP). In this paper, we aimed to retrospectively evaluate the combined diagnostic value of conventional magnetic resonance imaging (MRI) and whole-tumor histogram analysis of apparent diffusion coefficient (ADC) maps in the differentiation of the two lesions.MethodsIn total, 18 patients with orbital lymphoma and 22 patients with IOIP were included, who underwent both conventional MRI and diffusion weighted imaging before treatment. Conventional MRI features and histogram parameters derived from ADC maps, including mean ADC (ADCmean), median ADC (ADCmedian), skewness, kurtosis, 10th, 25th, 75th and 90th percentiles of ADC (ADC10, ADC25, ADC75, ADC90) were evaluated and compared between orbital lymphoma and IOIP. Multivariate logistic regression analysis was used to identify the most valuable variables for discriminating. Differential model was built upon the selected variables and receiver operating characteristic (ROC) analysis was also performed to determine the differential ability of the model.ResultsMultivariate logistic regression showed ADC10 (P = 0.023) and involvement of orbit preseptal space (P = 0.029) were the most promising indexes in the discrimination of orbital lymphoma and IOIP. The logistic model defined by ADC10 and involvement of orbit preseptal space was built, which achieved an AUC of 0.939, with sensitivity of 77.30% and specificity of 94.40%.ConclusionsConventional MRI feature of involvement of orbit preseptal space and ADC histogram parameter of ADC10 are valuable in differential diagnosis of orbital lymphoma and IOIP.
Highlights
The overlap of morphological feature and mean apparent diffusion coefficient (ADC) value restricted clinical application of magnetic resonance imaging (MRI) in the differential diagnosis of orbital lymphoma and idiopathic orbital inflammatory pseudotumor (IOIP)
Four qualitative variables were found significant in the univariate analysis for differentiating orbital lymphoma from IOIP, including tumor margin, degree of contrast enhancement, involvement of orbit preseptal space and findings suggestive of sinusitis
The ADCmean, ADCmedian, ADC10, ADC25, ADC75, and ADC90 were significantly lower in orbital lymphoma (P < 0.001), whereas kurtosis was significantly higher in lymphoma (P = 0.023), when compared to IOIP
Summary
The overlap of morphological feature and mean ADC value restricted clinical application of MRI in the differential diagnosis of orbital lymphoma and idiopathic orbital inflammatory pseudotumor (IOIP). We aimed to retrospectively evaluate the combined diagnostic value of conventional magnetic resonance imaging (MRI) and whole-tumor histogram analysis of apparent diffusion coefficient (ADC) maps in the differentiation of the two lesions. Orbital lymphoma and idiopathic orbital inflammatory pseudotumor (IOIP) represent the most common lymphoproliferative disorders affecting the orbit [1], accounting nearly 20% of all orbital mass lesions [1,2,3]. Dacryoadenitis and diffuse inflammation subtypes of IOIPs are misdiagnosed as lymphoma because of similar clinical and imaging findings [5]. Diffuse lymphocytic infiltrative IOIP, as the most common pathological subtype, could not be differentiated pathologically from orbital lymphoma [6]
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