Význam magnetické rezonance u nádorů rekta
| Title in English | The significance of magnetic resonance imaging rectal cancer |
|---|---|
| Authors | |
| Year of publication | 2017 |
| Type | Article in Periodical |
| Magazine / Source | Onkologie |
| MU Faculty or unit | |
| Citation | |
| Field | Other medical specializations |
| Keywords | magnetic resonance imaging; rectal cancer; staging; restaging; therapy response |
| Description | High-resolution magnetic resonance imaging (MRI) plays a pivotal role and has become almost mandatory in the pretreatment assessment of primary rectal cancer. The high soft-tissue contrast of MRI accurately assesses the extramural tumor spread and relation to mesorectal fascia and the sphincter complex and also the surrounding pelvic anatomy, and is increasingly being used to evaluate tumor resectability in patients with rectal cancer and to determine which patients can be treated with surgery alone and which will require radiation therapy to promote tumor regression. MRI is currently the only imaging modality that is highly accurate in predicting whether or not it is likely that a tumorfree margin can be achieved and thus provides important information for planning of an effective therapeutic strategy, especially in patients with advanced rectal cancer. The accuracy of MRI in assessing mesorectal lymph nodes remains moderate, as there are no reliable criteria to assess nodal involvement. In patients with rectal cancer who have received concurrent chemotherapy and radiation therapy before surgery, MRI has lower accuracy in prediction of the pathologic stage owing to overstaging or understaging. The factors related to this problem include fibrosis, desmoplastic reaction, edema, inflammation, and viable tumor nets at a fibrotic scar from a previous tumor. Reassessment of MRI scans after preoperative therapy has implications for surgical planning, the timing of surgery, sphincter preservation, deferral of surgery for good responders, and development of further preoperative treatments for radiologically identified poor responders. To identify patients with true complete pathological response before surgical resection remains a challenge. |