Biomedical subjects

Daniel Vanel

Publications and source records attributed to Daniel Vanel.

21 records · Page 2Linked to original sources

PubMed2002

Fast magnetic resonance imaging with contrast for soft tissue sarcoma viability.

Because dynamic (fast) contrast-enhanced magnetic resonance imaging with its temporal resolution allows evaluation of contrast kinetics of soft tissue sarcomas, its efficacy for defining viable tumor in these neoplasms was studied for three applications: biopsy localization, chemotherapeutic response, and differentiation between recurrence and inflammation after treatment. After conventional T1-weighted and T2-weighted magnetic resonance sequences to localize the lesion, patients had dynamic contrast-enhanced magnetic resonance imaging with fast and ultrafast sequences and postprocessing techniques (subtraction, time-intensity curves, and parametric color-encoding). In 10 of 40 patients, dynamic imaging more precisely defined the most malignant foci of tumor for biopsy than conventional magnetic resonance imaging. After chemotherapy, dynamic imaging distinguished 11 good responders from 21 poor responders. In followup of 196 patients, dynamic imaging detected 42 early enhancing recurrences and excluded recurrent tumor in six late enhancing pseudotumors. Dynamic imaging can differentiate viable tumor from nonviable tumor and inflammation by showing two temporally different phases of contrast enhancement: an early phase correlative with viable tumor at histologic examination, and a late phase when all tissues enhance simultaneously and may be indistinguishable. By showing tumor viability, dynamic contrast-enhanced magnetic resonance imaging can help define biopsy sites, chemotherapeutic response, and presence or absence of recurrences and therefore affect the initial evaluation, treatment, and followup of patients with soft tissue sarcomas.

Adult↗

PubMed1999

Dynamic Contrast-Enhanced MR Imaging for Soft Tissue Sarcomas.

Dynamic contrast-enhanced magnetic resonance imaging has recently emerged as an important method for evaluating soft tissue sarcomas for biopsy localization, chemotherapeutic response, and long-term follow-up because of its ability to detect viable tumor. This article presents the basic principles of contrast kinetics in soft tissue sarcomas after bolus injection of contrast agent and discusses the current postprocessing methods (subtraction, first-pass image and time-intensity curves with region of interest, and color-encoded techniques) used to display these dynamic studies. Because of its excellent temporal resolution, dynamic MR imaging can delineate the early uptake of contrast agent in sarcomas within seconds after injection, almost synchronous with arterial enhancement, and thereby differentiate the rapidly enhancing viable tumor from the nonenhancing necrotic tumor and the late enhancing changes after surgery, radiation therapy, and chemotherapy.

Journal Article↗

PubMed1999

MR Imaging in the Follow-Up Evaluation of Aggressive Soft Tissue Tumors.

Although newer imaging techniques aid in the diagnosis of soft tissue sarcomas and current surgical procedures and adjunct therapy decrease the incidence of their recurrences when patients are referred to oncologic centers, the majority of these tumors are suboptimally evaluated in general practice with frequent recurrences. Close surveillance of these patients is necessary for early recognition and treatment of recurrent disease. This article describes an organized, stepwise magnetic resonance imaging evaluation of these patients after surgery and radiation therapy. The initial sequence should be T2-weighted. Low signal intensity or diffuse high signal intensity without mass on T2-weighted sequence excludes recurrence in 99% of patients. A high signal intensity mass, however, should be studied with bolus injection of contrast medium. Although standard contrast-enhanced MR imaging differentiates the non-enhancing hygroma or hematoma from the enhancing recurrence or pseudotumor, dynamic contrast-enhanced MR imaging is required to distinguish the rapidly enhancing recurrent tumor from the slowly enhancing pseudotumor of inflammation.

Journal Article↗