Musculoskeletal neoplasm: perineoplastic edema versus tumor on dynamic postcontrast MR images with spatial mapping of instantaneous enhancement rates
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1Department of Radiology, University of California, San Francisco 94143, USA.
Purpose:
To evaluate the utility of fast, contrast-enhanced, sequential magnetic resonance (MR) imaging in differentiating between extraosseous tumor and perineoplastic edema.
Materials And Methods:
Fourteen patients underwent sequential MR imaging (3.5 seconds per image) after bolus administration of gadopentetate dimeglumine. Initial rates of enhancement (initial slope) were calculated on a pixel-by-pixel basis and displayed as a "slope image"' in which pixel intensity reflected the slope value. Close correlation with wedge biopsy specimens was performed.
Results:
Mean initial slope values were viable extraosseous tumor, 9.33 (standard deviation, 2.23); infiltrated muscle, 9.07 (2.31); edematous muscle without tumor infiltration, 5.48 (1.27); normal muscle, 1.11 (0.65). Differences in initial slope between all neoplastic and nonneoplastic tissues were statistically significant. Within individual patients, initial slope of edematous muscle was always 20% or more lower than that of neoplastic tissue. Slope images highlighted areas of viable extraosseous tumor and infiltrated muscle against edematous and normal tissues.
Conclusion:
Computer-generated slope images derived from sequential postcontrast MR images allow differentiation between tumor and nonneoplastic edema and may thereby guide the surgeon in planning limb-sparing procedures.
Insights
Fast, contrast-enhanced MRI can differentiate tumors from edema. Slope images derived from sequential magnetic resonance (MR) imaging highlight tumorous tissue, aiding surgical planning for limb-sparing procedures.
Area of Science:
- Radiology and Medical Imaging
- Oncology
- Musculoskeletal Imaging
Background:
- Differentiating extraosseous tumors from perineoplastic edema is crucial for surgical planning.
- Magnetic resonance (MR) imaging is a key modality for soft tissue evaluation.
Purpose of the Study:
- To assess the effectiveness of rapid, contrast-enhanced, sequential MR imaging in distinguishing between extraosseous tumors and perineoplastic edema.
- To evaluate the utility of "slope images" for this differentiation.
Main Methods:
- Fourteen patients underwent sequential MR imaging after gadopentetate dimeglumine administration.
- Pixel-by-pixel calculation of initial enhancement rates (initial slope) created "slope images".
- Correlation with wedge biopsy specimens was performed.
Main Results:
- Mean initial slope values differed significantly between neoplastic and nonneoplastic tissues.
- Tumorous tissues exhibited higher initial slope values compared to edematous or normal muscle.
- Slope images effectively highlighted viable extraosseous tumor and infiltrated muscle.
Conclusions:
- Computer-generated slope images from sequential postcontrast MR imaging can reliably differentiate tumor from nonneoplastic edema.
- This technique may assist surgeons in planning limb-sparing procedures.