Mechanism of Action Combidex in MR Imaging Mukesh Harisinghani, MD Department of Radiology,...
-
Upload
charles-gallagher -
Category
Documents
-
view
216 -
download
1
Transcript of Mechanism of Action Combidex in MR Imaging Mukesh Harisinghani, MD Department of Radiology,...
Mechanism of Action Combidex in MR Imaging
Mukesh Harisinghani, MD
Department of Radiology,
Massachusetts General Hospital
2
Overview
Current limitations for LN staging in cancer
Combidex enhanced MRI Mechanism of action
Fulfills unmet clinical need of staging LN in patientswith known primary cancer
3
Why Image Lymph Nodes?
Accurate staging of the primary cancer
Appropriate treatment
Prostate Cancer
LN Positive Treatment changed to non-surgical
Get a sense of the prognosis
Bladder Cancer
Node Negative 10-year survival 57–87%
Node Positive 5-year survival 35–38%
Risk of death increases 20% with each additional + LN
Cheville et al. Cancer 97, 2003.
4
Current LN Staging
Non-InvasiveNon-Invasive
ImagingImaging
InvasiveInvasive
Surgical LN Sampling (gold standard)Surgical LN Sampling (gold standard)
5
Size Criteria
< 10 mm< 10 mm
< 8 mm< 8 mm
BenignBenign
> 10 mm> 10 mm
> 8 mm> 8 mm
MalignantMalignant
BenignBenign MalignantMalignant
18 mm in short axis 5 mm in short axis
Size criterion is inaccurateSize criterion is inaccurate
Morphology – Fatty Hilum
MalignantMalignantBenignBenign
8
Morphology – Central Necrosis
CT in Cervical Cancer
Positive predictive valueof 100% for nodal metastases
Most necrotic nodes haddiameter > 2 cm
Yang et al. AJR 2000;175.
9
Pelvic Lymphadenectomy
Pelvic lymph node dissection (PLND) accompanied by frozen section pathological examination
Standard pelvic lymphadenectomyis limited
Extended pelvic lymphadenectomy
Incidence of lymph node metastases increased from 10% to 26.2%
Heidenreich et al. J Urol. April 2002.
Extended lymph node dissection Obturator nerve injury Trauma to major vessels
Narayan et al. Urology 1994;44:519–24.
Frozen section pathologic analysis has false negative rate of 30–40%
Young et al. J Clin Path 52,1999.
11
Current Need
Non-invasive techniqueNon-invasive technique that detects andcharacterizes LN with high degreeof sensitivity and specificity
Broad anatomic coverageBroad anatomic coverage for all LN
Combidex(ferumoxtran-10)
NanoparticlesSize: 21 nmR1: 17 mMsec-1R2: 48 mMsec-1
Uptake by normal lymph nodes
Combidex(ferumoxtran-10)
14
Technique
1.5 T MR systems using pelvic phasearray coil (Siemens Magnetom, GE Horizon)
Imaging time/sequences (25 minutes/patient) T2 FSE sequences T2* gradient echo sequences 3D gradient echo sequences
Post-processing 3D reconstruction
Pre-contrastPre-contrast Post-contrastPost-contrast
24 hours
20 mm20 mm
Unenhanced MRUnenhanced MR Combidex enhanced MRCombidex enhanced MR
20
Clinical Impact
Improved clinical staging
Surgical planning
Radiation therapy planning
Image-guided intervention
COMBIDEX®COMBIDEX®
(ferumoxtran-10)(ferumoxtran-10)