| Abstract | Konvencionalne tehnike magnetne rezonancije (MR) nisu pouzdane u definiranju histološkog tipa i stupnja biološkog potencijala tumora, kao i razlikovanju tumora od peritumorskog vazogenog edema. Difuzijski mjerene snimke MR-a s mapama pojavnog difuzijskog koeficijenta (engl. apparent diffusion coefficient - ADC) pružaju informaciju o gustoći stanica u tumoru i peritumorskom tkivu. Stoga smo pretpostavili da je mjerenjem ADC-a tumora, u kombinaciji s morfološkim snimkama, moguće razlikovati histološke tipove tumora i njihov stupanj, te razlikovati tumor od vazogenog edema. U istraživanje je prospektivno uključeno 149 bolesnika s novootkrivenim intrakranijskim tumorom, uz patohistološki dokaz korištenjem trajnih rezova, a kontrolni uzorak bilo je normalno tkivo suprotne moždane hemisfere. Snimanja su provedena na MR uređaju snage magnentog polja 1,5 Tesla, s mjerenjem ADC-a postavljanjem uniformnih mjernih područja. Usporedba tipova tumora provedena je između tumora koji se međusobno teško razlikuju neinvazivnim metodama dijagnostike. Na modelu astrocitnih tumora II. – IV. stupnja analizirali smo razlike difuzije između stupnjeva tumora, a razlikovanje peritumorskog edema od infiltracije provedeno je usporedbom ADC-a peritumorskih područja neinfiltrativnih tumora, odnosno metastatskih karcinoma, s onim infiltrativnih, odnosno anaplastičnih astrocitoma i multiformnog glioblastoma. Povezanost varijabli ispitana je parnim t-testom i neparametrijskim testovima, uz razinu značajnosti pri p<0,05. Na temelju difuzijskih osobina mogli smo razlikovati pilocitični astrocitom od ependimoma, disembrioplastični neuroepitelijalni tumor od astrocitoma ili oligodendroglioma II. stupnja i meningeom od Schwannoma, a u ograničenom broju bolesnika moglo se razlikovati oligodendrogliom i astrocitom II. stupnja, te glioblastom i metastatski karcinom. Također je bilo moguće razlikovati astrocitom II. stupnja od tumora visokog stupnja, te vazogeni edem od tumorske infiltracije. Kvantifikacija pojavnog difuzijskog koeficijenta omogućava preciznije postavljanje prijeoperacijske dijagnoze u odabranim slučajevima, u kombinaciji s konvencionalnim pregledom MR-a i s osnovnim kliničkim podacima. |
| Abstract (english) | Conventional magnetic resonance imaging (MRI) is not reliable in the definition of histological type and tumor grade and in the distinction of tumor from peritumoral vasogenic edema. Diffusion-weighted MRI with maps of apparent diffusion coefficient (ADC) provides the information about the cellularity of the tumor and peritumoral tissue. Therefore, we assumed that it is possible to distinguish tumor type and grade, as well as to differentiate tumor from vasogenic edema, by means of ADC measurement combined with morphological images. The investigation prospectivelly included 149 patients with newly discovered intracranial tumor which was pathohistologically confirmed using permanent sections. Contralateral normal tissue served as a control sample. Imaging was performed on a 1.5 Tesla MRI scanner. The comparison of tumor types was performed between radiologically similar tumors. We analyzed diffusion differences according to tumor grade on a model of astrocytic tumors grade II-IV, and the distinction of tumor from edema was made by the comparison of peritumoral ADCs of metastatic carcinomas as non-infiltrative tumors, with peritumoral areas of anaplastic astrocytomas and glioblastomas, as infiltrative tumors. The relationship between variables was assesed by t-test and non-parametric tests, with a p<0.05. Diffusion properties enabled distinction of pilocityc astrocytoma from ependymoma, dysembrioplastic neuroepithelial tumor from grade II astrocitoma or oligodendroglioma and meningioma from Schwannoma, while grade II oligodendroglioma and astrocytoma were distinguishable in a limited number of patients, as well as glioblastoma and metastatic carcinoma. With respect to the tumor grade, low grade astrocytoma had higher ADC from high grade astrocytomas, while vasogenic edema and tumor had significantly different ADCs. The quantification of ADC enables high precision of preoperative diagnosis in selected cases, if combined with conventional MRI and basic clinical data. |
