PURPOSE To compare high resolution T2 sequences and post Gadolinium T1 sequences in the diagnosis and preoperative staging of perianal and anal fistulas. METHOD AND MATERIALS 40 patients (15 with chronic inflammatory bowel disease) with clinical evidence or suspicion of anal fistulas underwent pelvic MRI (1.5 T) performed with phased-array coil. Images were obtained in the axial and coronal planes using TSE T2-weighted high resolution sequences, T2-weighted HASTE and T1-weighted FLASH sequences after gadolinium enhancement. Following parameters were considered: presence of a fistula and relationship with the sphincters, presence of abscesses or complications. All patients underwent surgery, considered the gold standard. MRI and surgical findings were assessed using the Park’s fistula-in-ano classification and the St. James MR imaging classification of perianal fistulas. RESULTS MRI documented no evidence of fistula in 4 patients, intersphinteric fistulas in 11 (grade 1 and 2 St. James), trans-sphincteric fistulas in 17 (grade 3 and 4 St. James), translevator in 4 (grade 5) and complex ano-rectum-vaginal fistulas in 4. Concordance with surgery was 87.5%. The weighted K coefficient of the interobserver agreement for high resolution T2 sequences resulted 0.89 and for post gadolinium T1 sequences was 0.89. The weighted k coefficient of intraobserver agreement for two observers were 0.88 and 0.93. The agreement between high resolution T2 and post gadolinium T1 sequences, stratified by observer was 0.92. The χ2 test for heterogeneity of agreement between the two observers was 0.648, p=0.421. CONCLUSIONS MRI is an accurate technique for the identification and classification of anal and perianal fistulas and their complications. Both high resolution T2 and T1 post gadolinium sequences resulted adequate for classifying fistulas. No evidence of heterogeneity of agreement was found.
Role of Phased Array MRI in the Diagnosis and Preoperative Classification of Perianal and Anal Fistulas: Comparison between High-Resolution T2 and T1 Post-Gadolinium Sequences / De Vargas Macciucca, M.; Maccioni, Francesca; Colaiacomo, M. C.; Panzironi, Giuseppe; Manganaro, Lucia; Marini, Mario. - ELETTRONICO. - (2004). (Intervento presentato al convegno Radiological Society of North America - Annual Meeting tenutosi a Chicago nel 12/01/2004).
Role of Phased Array MRI in the Diagnosis and Preoperative Classification of Perianal and Anal Fistulas: Comparison between High-Resolution T2 and T1 Post-Gadolinium Sequences
MACCIONI, Francesca;PANZIRONI, Giuseppe;MANGANARO, Lucia;MARINI, Mario
2004
Abstract
PURPOSE To compare high resolution T2 sequences and post Gadolinium T1 sequences in the diagnosis and preoperative staging of perianal and anal fistulas. METHOD AND MATERIALS 40 patients (15 with chronic inflammatory bowel disease) with clinical evidence or suspicion of anal fistulas underwent pelvic MRI (1.5 T) performed with phased-array coil. Images were obtained in the axial and coronal planes using TSE T2-weighted high resolution sequences, T2-weighted HASTE and T1-weighted FLASH sequences after gadolinium enhancement. Following parameters were considered: presence of a fistula and relationship with the sphincters, presence of abscesses or complications. All patients underwent surgery, considered the gold standard. MRI and surgical findings were assessed using the Park’s fistula-in-ano classification and the St. James MR imaging classification of perianal fistulas. RESULTS MRI documented no evidence of fistula in 4 patients, intersphinteric fistulas in 11 (grade 1 and 2 St. James), trans-sphincteric fistulas in 17 (grade 3 and 4 St. James), translevator in 4 (grade 5) and complex ano-rectum-vaginal fistulas in 4. Concordance with surgery was 87.5%. The weighted K coefficient of the interobserver agreement for high resolution T2 sequences resulted 0.89 and for post gadolinium T1 sequences was 0.89. The weighted k coefficient of intraobserver agreement for two observers were 0.88 and 0.93. The agreement between high resolution T2 and post gadolinium T1 sequences, stratified by observer was 0.92. The χ2 test for heterogeneity of agreement between the two observers was 0.648, p=0.421. CONCLUSIONS MRI is an accurate technique for the identification and classification of anal and perianal fistulas and their complications. Both high resolution T2 and T1 post gadolinium sequences resulted adequate for classifying fistulas. No evidence of heterogeneity of agreement was found.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
