Diagnostic value of quantitative SPECT/CT in assessing active sacroiliitis in patients with axial spondylarthritis and/or inflammatory low back pain

Fundamento. La precisión diagnóstica de la gammagrafía ósea (GO) aumenta con las imágenes SPECT/TAC haciendo conveniente reevaluar su utilidad diagnóstica en la sacroilitis de la espondiloartritis axial (EA). El objetivo fue comparar el rendimiento diagnóstico de la resonancia magnética (RM), la SPECT/TC y ambas pruebas combinadas, y evaluar la correlación entre los índices cuantitativos de ambas técnicas. Métodos. A 31 pacientes con EA activa y 22 con lumbalgia inflamatoria se les realizó una RM y una SPECT/TC de las articulaciones sacroilíacas y se calculó la precisión diagnóstica de ambas técnicas respecto al diagnóstico clínico. La correlación entre ambas pruebas se calculó comparando los índices de actividad del SPECT/TC con los sistemas de puntuación Berlín y SPARCC de RM. Resultados. Los valores de sensibilidad y especificidad de la SPECT/TC cuantitativa, tomando como punto de corte el cociente sacroilíaca/promontorio >1,36, fueron similares a los publicados para la RM. La combinación de ambas técnicas aumentó la sensibilidad manteniendo una alta especificidad. La correlación entre las escalas totales de RM y SPECT/TC fue moderada y mejoraba al utilizar únicamente las escalas de inflamación. Conclusiones. La SPECT/TC cuantitativa muestra una mejor precisión diagnóstica que la GO planar en la sacroilitis activa y una correlación moderada con las puntuaciones de RM. La combinación de ambas técnicas aumenta la precisión diagnóstica. Por tanto, la SPECT/TAC cuantitativa podría tener un papel relevante en el diagnóstico de sacroilitis en pacientes con alta sospecha de EA y RM negativa/no concluyente o en aquellos pacientes en los que no se pueda realizar una RM.(AU)

Background. The diagnostic accuracy of bone scintigraphy (BS) increases with SPECT/CT imaging. It would therefore be appropriate to reassess the diagnostic utility of scintigraphy in sacroiliitis with axial spondyloarthritis (SpA). The aim of this study was to compare the diagnostic performance of MRI, SPECT/CT and a combination of both techniques in sacroiliitis, and to evaluate the correlation between quantitative SPECT/CT indices and quantitative MRI inflammatory lesion scores. Methods. Thirty-one patients with active SpA and 22 patients with inflammatory low back pain underwent MRI and SPECT/CT of the sacroiliac joints. The diagnostic accuracy of both techniques was calculated using clinical diagnosis as the gold standard. The correlation between MRI and SPECT/CT was calculated by comparing the SPECT/CT activity indices and the Berlin/SPARCC scoring systems for MRI. Results. The sensitivity and specificity values in quantitative SPECT/CT, taking the sacroiliac/promontory ratio of >1.36 as the cut-off value, were close to those from MRI published in the literature. The combination of both techniques increased sensitivity while maintaining high specificity. There was a moderate correlation between SPECT/CT and MRI total scores. This correlation was improved by using solely the MRI inflammation scores. Conclusion. Quantitative SPECT/CT showed better diagnostic accuracy than planar scintigraphy and showed a moderate correlation with MRI scores in active sacroiliitis. The combination of both tests increased the diagnostic accuracy. Quantitative SPECT/CT could play a relevant role in the diagnosis of active sacroiliitis in patients with high a suspicion of SpA and a negative/inconclusive MRI test or in patients with whom MRI studies cannot be carried out.(AU)

Diagnostic value of quantitative SPECT/CT in assessing active sacroiliitis in patients with axial spondylarthritis and/or inflammatory low back pain.

BACKGROUND: The diagnostic accuracy of bone scintigraphy (BS) increases with SPECT/CT imaging. It would therefore be appropriate to reassess the diagnostic utility of scintigraphy in sacroiliitis with axial spondyloarthritis (SpA). The aim of this study was to compare the diagnostic performance of MRI, SPECT/CT and a combination of both techniques in sacro-iliitis, and to evaluate the correlation between quantitative SPECT/CT indices and quantitative MRI inflammatory lesion scores. METHODS: Thirty-one patients with active SpA and 22 patients with inflammatory low back pain underwent MRI and SPECT/CT of the sacroiliac joints. The diagnostic accuracy of both techniques was calculated using clinical diagnosis as the gold standard. The correlation between MRI and SPECT/CT was calculated by comparing the SPECT/CT activity indices and the Berlin/SPARCC scoring systems for MRI. RESULTS: The sensitivity and specificity values in quantitative SPECT/CT, taking the sacroiliac/promontory ratio of >1.36 as the cut-off value, were close to those from MRI published in the literature. The combination of both techniques increased sensitivity while maintaining high specificity. There was a moderate correlation between SPECT/CT and MRI total scores. This correlation was improved by using solely the MRI inflammation scores. CONCLUSION: Quantitative SPECT/CT showed better diagnostic accuracy than planar scintigraphy and showed a moderate correlation with MRI scores in active sacroiliitis. The combination of both tests increased the diagnostic accuracy. Quanti-tative SPECT/CT could play a relevant role in the diagnosis of active sacroiliitis in patients with high a suspicion of SpA and a negative/inconclusive MRI test or in patients with whom MRI studies cannot be carried out.

CT and MRI in fat-containing papillary renal cell carcinoma.

We present a case, pathologically proven, of a patient with multiple papillary renal cell carcinoma (PRCC) with bilateral and synchronous affectation. CT showed fatty tissue inside one of the lesions and numerous calcified lesions. The study with MR demonstrated multiple and hypointense lesions in T2 and contrast enhancement in T1. Our observations confirm that the presence of multiple lesions with fat and calcified deposits and poor contrast enhancement should be diagnosed as PRCC, rather than renal clear cell carcinoma (RCCC) or renal angiomyolipoma.