Introduction: Magnetic resonance (MR) imaging is a method of choice in diagnosing internal soft tissue injuries of the knee, such as menisci, cruciate ligaments and joint cartilage. It is, as well, the only method for detecting posttraumatic changes in bone marrow, so called bone bruises. Precise analysis of presence and location of bone bruise can explain the pattern of the knee trauma which enables better insight into internal knee lesions. Aim : The aim of the dissertation is to determine the difference in sensitivity of STIR sequence comparing to T1 on MR imaging for detecting bone bruises. The second aim is to determine the importance of bone bruise as the additional sign for detecting post injury lesions of anterior cruciate ligament (ACL) and menisci by determing their association. The additional aim is to determine the association of bone bruise frequency with injuries of ACL regarding the sport. Material and methods: A representative review of 100 MR examinations for the acute knee trauma in different sports was conducted. All the patients were examined within one month of trauma. All MR examinations were performed by using MRP 7000 0.3 T Hitachi MR unit. The standard imaging protocol with SE T1 sagital, FS T2 sagital, coronal, axial and STIR sequence was used. The presence and site of bone bruises were analyzed as well as the difference in bone bruise frequency on STIR and T1 sequence and the level of sensitivity of these sequencies in detecting bone bruises. The frequency of soft tissue lesions of the knee especially ACl and menisci and their association with bone bruises was also analyzed. We have also analyzed the frequency of bone bruises in different sports which led to the knee trauma. Results : Posttraumatic bone bruise was seen in 51 % of patients. Bone bruise was after the knee effusion, the second most often pathological finding on knee MR imaging. The highly statistically significant difference (estimated by Vilcoxon test Z=-5,067,p=0,000 ) was found between T1 and STIR sequence which leads to the conclusion that STIR sequence is much more sensitive in detecting the bone bruise than T1 sequence. The association between bone bruise and ACL lesion was statistically significant which posed bone bruise as the additional sign for detecting ACL injury which can be not so clear on MR imaging. The association between bone bruise and menisci lesion was not found. The frequency of bone bruise appearance was much higher (more than 50%) in certain sports (skiing, football and handball).Bone bruise with ACL lesion was more often in recreational athletes than in professionals. Conclusion :Bone bruise is best seen in STIR images. The association between bone bruise and ACL lesion was highly statistically significant which makes bone bruise significant additional sign in diagnosing ACL lesion. The most extensive knee lesions with bone bruise and ACL lesions are seen in skiing, football and handball. Magnetna rezonanca (MR) je metoda izbora za dijagnostikovanje povreda unutrašnjih mekotkivnih struktura, kao što su meniskusi, ukrštene veze i zglobna hrskavica. Osim toga, MR je jedina dijagnostička metoda koja prikazuje i posttraumatske promene koštane srži, zvane koštane modrice (KM). Preciznom analizom prisustva i lokacije KM se može razjasniti mehanizam traume kolena, što omogućava bolji uvid u očekivane, udružene, povrede unutrašnjih struktura kolena. Cilj : Cilj disertacije je da se utvrdi razlika u stepenu senzitivnosti STIR u odnosu na T1 sekvencu u detekciji koštanih modrica. Potom da se analizom stepena udruženosti KM i lezija prednjeg ukrštenog ligamenta(ACL) i meniskusa utvrdi značaj KM kao pomoćnog znaka za dijagnostikovanje povreda prednjeg ukrštenog ligamenta i meniskusa. Utvrditi učestalost KM i lezija ACL po sportovima. Materijal i metode : Urađen je MR pregled kolena kod 100 ispitanika sa akutnom povredom kolena, zadobijenom pri sportu. Svi su pregledani u prvih mesec dana nakon traume. Pregledi su obavljeni na MRP 7000 0,3T Hitači. Korišćen je standardizovani protokol sa sekvencama SE T1 sagitalno, FS T2 sagitalno, koronalno i aksijalno i STIR koronalno. Analizirano je prisustvo i raspored koštanih modrica. Analizirana je razlika učestalosti nalaza KM u STIR u odnosu na T1 sekvencu i procena vidljivosti KM u ove obe sekvence. Analizirana je učestalost patoloških nalaza na mekim tkivima kolena, posebno patoloških nalaza na ACL i meniskusima i njihova povezanost sa nalazima košatnih modrica. Analizirali smo učestalost nalaza KM po sportovima pri kojima je došlo do povrede kolena. Rezultati : Nalaz KM je uočen kod 51% ispitanika. KM je drugi, posle efuzije, po učestalosti patološki nalaz na MR pregledu kod akutne traume kolena. Utvrđena je značajna statisička razlika Vilkokson testom (Z=-5,067, p=0,000) između T1 i STIR sekvence što govori da je STIR sekvenca ubedljivo senzitivnija od T1 sekvence za dijagnostiku KM. Uočena je značajna statisitička povezanost između nalaza KM i nalaza lezije prednjeg ukrštenog ligamenta što ukazuje da nalaz KM možemo koristiti kao pomoćni znak za pouzdaniju dijagnostiku lezije ACL, a koja na MR pregledu može biti manje jasna. Nije uočena statistički značajna povezanost između nalaz a KM i lezije meniskusa. Uočeno je da je učestalost nalaza KM bila veća od 50% pri povredama u skijanju, fudbalu i rukometu. Nalaz KM udružen sa povredama ACL je bio oko dva puta učestaliji kod rekreativnih nego kod profesionalnih sportista. Zaključak : Zaključeno je da bolju vidljivost KM daje STIR sekvenca nego T1 sekvenca. Uočena je statistički visoko značajna povezanost nalaza KM sa nalazom lezije ACL, što opravdava značaj nalaza KM kao pomoćnog znaka u dijagnostici lezija ACL. Najekstenzivnije lezije kolena sa, visokim stepenom nalaza KM i lezija ACL, preko 50%, su u skijanju, fudbalu i rukometu.