Combined Ultrasmall Superparamagnetic Particles of Iron Oxide–Enhanced and Diffusion-Weighted Magnetic Resonance Imaging Reliably Detect Pelvic Lymph Node Metastases in Normal-Sized Nodes of Bladder and Prostate Cancer Patients

• Published in: European urology 2009-04, Vol.55 (4), p.761-769
• Main Authors: Thoeny, Harriet C, Triantafyllou, Maria, Birkhaeuser, Frederic D, Froehlich, Johannes M, Tshering, Dechen W, Binser, Tobias, Fleischmann, Achim, Vermathen, Peter, Studer, Urs E
• Format: Article
• Language: English
• Subjects: Aged; Biological and medical sciences; Bladder cancer; Contrast Media; Dextrans; Diffusion Magnetic Resonance Imaging - methods; Diffusion weighted MRI; Extended pelvic lymphadenectomy; Female; Ferrosoferric Oxide; Hematologic and hematopoietic diseases; Humans; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Lymph node metastasis; Lymphatic Metastasis; Magnetite Nanoparticles; Male; Medical sciences; Middle Aged; Neoplasm Staging; Nephrology. Urinary tract diseases; Pilot Projects; Prostate cancer; Prostatic Neoplasms - pathology; Reproducibility of Results; Tumors of the urinary system; Urinary Bladder Neoplasms - pathology; Urinary tract. Prostate gland; Urology; USPIO
• ISSN: 0302-2838; 1873-7560
• DOI: 10.1016/j.eururo.2008.12.034

Abstract Background Lymph node staging of bladder or prostate cancer using conventional imaging is limited. Newer approaches such as ultrasmall superparamagnetic particles of iron oxide (USPIO) and diffusion-weighted magnetic resonance imaging (DW-MRI) have inconsistent diagnostic accuracy and are difficult to interpret. Objective To assess whether combined USPIO and DW-MRI (USPIO–DW-MRI) improves staging of normal-sized lymph nodes in bladder and/or prostate cancer patients. Design, setting, and participants Twenty-one consecutive patients with bladder and/or prostate cancer were enrolled between May and October 2008. One patient was excluded secondary to bone metastases detected on DW-MRI with subsequent abstention from surgery. Intervention Patients preoperatively underwent 3-T MRI before and after administration of lymphotropic USPIO using conventional MRI sequences combined with DW-MRI. Surgery consisted of extended pelvic lymphadenectomy and resection of primary tumors. Measurements Diagnostic accuracies of the new combined USPIO–DW-MRI approach compared with the “classic” reading method evaluating USPIO images without and with DW-MRI versus histopathology were evaluated. Duration of the two reading methods was noted for each patient. Results and limitations Diagnostic accuracy (90% per patient or per pelvic side) was comparable for the classic and the USPIO–DW-MRI reading method, while time of analysis with 80 min (range 45–180 min) for the classic and 13 min (range 5–90 min) for the USPIO–DW-MRI method was significantly shorter ( p < 0.0001). Interobserver agreement (three blinded readers) was high with a kappa value of 0.75 and 0.84, respectively. Histopathological analysis showed metastases in 26 of 802 analyzed lymph nodes (3.2%). Of these, 24 nodes (92%) were correctly diagnosed as positive on USPIO–DW-MRI. In two patients, one micrometastasis each (1.0 × 0.2 mm; 0.7 × 0.4 mm) was missed in all imaging studies. Conclusions USPIO–DW-MRI is a fast and accurate method for detecting pelvic lymph node metastases, even in normal-sized nodes of bladder or prostate cancer patients.