Flavia Martins Costa MD, Abstract Co-Author: Nothing to Disclose

Evandro Miguelote Vianna MD, Presenter: Nothing to Disclose

Romeu Cortes Domingues MD, Abstract Co-Author: Nothing to Disclose

Romulo Cortes Domingues MD, Abstract Co-Author: Nothing to Disclose

Thomas Doring, Abstract Co-Author: Nothing to Disclose

Walter Meohas, Abstract Co-Author: Nothing to Disclose

Jose Francisco Rezende MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To assess the value of single-voxel proton MR spectroscopy, diffusion-weighted (DWI) and dynamic contrast–enhanced perfusion MR imaging in differentiating abscesses and hematomas from malignant necrotic soft-tissue tumors.

12 patients with necrotic soft-tissue masses, proven by histology (7 malignant, 2 abscesses and 3 hematomas),underwent MR imaging in a 1.5T scanner. In addition to conventional MR imaging protocol, DWI was performed with different b values (b=0-600 s/mm2) and the flow-insensitive diffusion coefficient (FIDC) was calculated in the solid part of the masses and the minimum, maximum and medium ADC value were calculated in the necrotic center. Dynamic images were acquired using T1-WI GRE sequence after contrast injection and the slope value (%per min) was calculated by the percentage increase in signal intensity obtained in the earliest contrast-enhancing part of the masses. Single-voxel proton MR spectroscopy (TE= 135 ms) was obtained on area of early enhanced, and the presence of choline peak was assessed. The statistical analysis was performed assessing the value of each advanced MR imaging technique in differentiating abscesses/hematomas from malignant necrotic soft-tissue tumors, and p<0.01 was considered significant.

A significant difference (p<0.001) between slope value of abscesses / hematomas and malignant tumors (mean±SD=15±12 vs.127±48%per min) was demonstrated. There was a difference (p<0.01) between maxADC from necrotic center of abscesses/ hematomas and malignant tumors (mean±SD=1.82±0.87 vs. 3.44±1.05x10-3mm2/s). There was no difference (p>0.01) between FIDC of abscesses/ hematomas and malignant tumors (mean±SD=1.54±0.53 vs. 1.33±0.80x10-3mm2/s) nor between minADC and medADC of abscesses/ hematomas and malignant tumors. A Cho peak was detected in every malignant tumors and in 2 abscesses but in non of the hematomas.

The DWI and perfusion MR imaging are useful techniques for differentiating abscesses/hematomas from malignant necrotic soft-tissue tumors, adding important information to the clinical history and conventional MR imaging for the differential diagnosis.

To determine if single-voxel proton MR spectroscopy, DWI and dynamic contrast–enhanced perfusion MR imaging, can differentiate abscesses and hematomas from malignant necrotic soft-tissue tumors.

Costa, F, Vianna, E, Domingues, R, Domingues, R, Doring, T, Meohas, W, Rezende, J, et al, , The Value of Single-voxel Proton MR Spectroscopy, Diffusion-weighted, and Dynamic Contrast–enhanced Perfusion MR Imaging in Differentiating Abscesses and Hematomas from Malignant Necrotic Soft-tissue Tumors.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6014942.html