Optimization of magnetic resonance protocol in visualization of the knee joint using 3 Tesla

Uvod: magnetno rezonantni imidžing (MR) je u širokoj uporebi u dijagnostici patoloških poremećaja ekstremiteta. Postoji interes da se redukuje vreme trajanja snimanja tokom pregleda kako bi se povećao komfor pacijenata i redukovali problemi koji su u vezi sa klaustrofobijom i artefaktima koji nastaju pri pomeranju pacijenta tokom dugih snimanja. Trodimenzionalne (3D) izovoksel sekvence pokazale su značajne mogućnosti u redukciji vremena snimanja MR pregledom zgloba kolena bez smanjenja kvaliteta dijagnostičkih mogućnosti. Cilj: uporediti dijagnostičke mogućnosti rutinskog, 2D MR protokola, na 3.0 Tesla MR aparatu, sa 3D True fast imaging, TrueFISP, izovoksel sekvencom u detekciji hondralnih oštećenja, ruptura prednjeg ukrštenog ligamenta (LCA), ruptura meniskusa i abnormalnosti subhondralne kosti, u korelaciji sa artroskopijom, kao referentnim standardom. Materijal i metode: Studija je odobrena od institucionalnog etičkog odbora. Pacijenti su informisani o studiji i potpisali pristanak za učešće u istraživanju. 76 zgloba kolena kod 76 pacijenata (34 ženskog pola; prosečne starosti 36 godina) uključeno je u prospektivnu studiju, snimljeno je standardnim 2D MR protokolom snimanja i 3D TrueFISP sekvencom u sagitalnoj ravni. Svim pacijentima je urađena artroskopija u periodu od maksimum 30 dana nakon snimanja. Dva radiologa, nezavisno jedan od drugog, su evaluirala dobijene snimke. Preciznost u detekciji hondralnih oštećenja, ruptura LCA i meniskusa, i abnormalnosti subhondralne kostne srži je određena podudarnošću radioloških i artroskopskih nalaza kao i proverom podudaranja ove dve metode snimanja. Rezultati: prosečna senzitivnost i specifičnost 3DTrueFISP sekvence je bila 75%, 94% respektivno, u dijagnostici oštećenja hrskavice, 97%, 97% u detekciji ruptura LCA, 65%, 89% u postavljanju dijagnoze ruptura meniskusa, a dobra podudarnost radioloških nalaza je dobijena u interpretaciji oštećenja subhondralne kosti. Standardnim 2D MR protokolom prosečna senzitivnost i specifičnost je bila 70%, 93%, respektivno, u postavljanju dijagnoze hondralnih oštećenja, 94% i 100% u postavljanju dijagnoze rupture LCA, 65%, 88% u detekciji ruptura meniskusa. Zaključak: dijagnostičke mogućnosti upotrebom 3DTrueFISP sekvence su uporedive sa standardnim, 2D, MR protokolom u snimanju zgloba kolena.Introduction: Magnetic resonance imaging (MR) is widely used to assess internal derangements of the extremities. There is an interest in decreasing examination times to improve patient comfort and reduce the problems related to claustrophobia and motion artifacts, which occur more commonly with long examinations. The three-dimensional (3D) isovoxel true FISP sequence facilitates a noticeable reduction in acquisition time for MR imaging of the knee without reducing diagnostic performance. Objective: To compare the diagnostic performance of conventional, 2D, MR protocol, at 3.0 Tesla MR, with 3D water-excitation true fast imaging with steady-state precession, TrueFISP, an isotropic resolution sequence for detecting articular cartilage defects, anterior crucial ligament tears, meniscal tears and subhondral bone changes of the knee joint, with arthroscopy as reference standard. Materials and methods: The study was institutional review board approved. Written informed consent was obtained from all patients. 76 knees of 76 patients (34 females; mean age 36 years) were prospectively examined by using a conventional 2D MR protocol and sagittal 3D TrueFISP sequence. All patients underwent arthroscopy within a maximum period of 30 days after imaging. Two blinded readers evaluated the MR images. Accuracy for detection of cartilage defects, anterior cruciate ligament and meniscal tears, and subchondral bone abnormalities interobserver agreement, and intermethod agreement were calculated. Results: Overall sensitivity and specificity of 3DTrueFISP sequence were, respectively, 75%, 94% for diagnosis cartilage defects, 97%, 97%, for a diagnosis ACL tears, 65%, 89% for diagnosis of meniscal tears and with good interobserver agreement in interpretation of subhondral bone abnormalities. The standard MR protocol had overall sensitivities and specificities 70%, 93%, respectively, for diagnosis of cartilage defects, 94% and 100% for diagnosis ACL tears and 65%, 88% for diagnosis meniscal tears. Conclusion: The diagnostic perfomance of knee MR imaging performed by using a 3DTrueFISP sequence is comparable to the diagnostic performance of the conventional, 2D, MR protocol