Mukesh Gobind Harisinghani MD, Presenter: Nothing to Disclose

Mansi Awasthi Saksena MD, Abstract Co-Author: Nothing to Disclose

Peter Florin Hahn MD, Abstract Co-Author: Nothing to Disclose

John Kim MD, Abstract Co-Author: Nothing to Disclose

Maha Torabi MD, Abstract Co-Author: Nothing to Disclose

Peter R Mueller MD, Abstract Co-Author: Nothing to Disclose

MR imaging with ferumoxtran-10 (Combidex(r); Advanced Magnetics, Cambridge, MA; Sinerem(r); Guerbet, Paris, France) can be used to detect nodal metastases based on the susceptibility effect the agent has on T2* weighted sequences. The purpose of this study was to assess the optimal Time to echo (TE) value for T2* weighted gradient echo imaging during ferumoxtran-10 enhanced MR lymphangiography for detecting metastatic nodal disease

56 patients (M:F; 42:14) with various primary malignancies [bladder (13), breast (9), penile (2), prostate (24), rectal (1), testes (5), urethra (2)] and scheduled for surgical lymph node dissection were evaluated with T2* weighted gradient echo images obtained before and 24-36 hours after the administration of ferumoxtran-10 (2.6 mg/kg). Dual echo sequences with two time to echo values of 14 msec and 24 msec were performed with all other parameters remaining the same (TR, 2100; FA 70°; FOV 24-26; slice thickness 3mm; matrix, 160x256; number of excitations 2).140 nodes were detected which were analyzed by two blinded readers using a 6 point scale to characterize the nodes with the differences settled by consensus. Receiver operating curve (ROC) analysis was performed to compare images with TE 14 and TE 24

Of the evaluated 140 nodes 45 were benign and 95 were malignant on histopathological analysis. The results for the ROC analysis comparing images with TE 14 msec [Az = 0.918 95% CI (0.86-0.97)] and images with a TE of 24 msec [Az =0.93 95% CI (0.88-0.98)] showed no statistically significant difference (p= 0.4). However, the area under the curve was higher for 24 msec than 14 msec. When primary efficacy parameters were calculated for the two, TE of 24 msec gave higher specificity (TE 24 specificity 86.7%, TE 14 specificity 80%) while the TE of 14 msec gave higher sensitivity ( TE 14 sensitivity 91.5%, TE 24 sensitivity 89.4%)

Images at a higher TE of 24 msec provide better specificity over a shorter TE value of 14 msec while the shorter TE value of 14 msec provides a higher sensitivity. Therefore, the ideal T2* weighted imaging with ferumoxtran-10 should include a dual echo sequence with TE values of 14 and 24 msec

M.G.H.: GERRAF Fellow

Harisinghani, M, Saksena, M, Hahn, P, Kim, J, Torabi, M, Mueller, P, Optimal Time to Echo (TE) Value for T2-weighted Gradient Echo Imaging with Ferumoxtran-10.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4415145.html