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T-staging of rectal cancer: accuracy of 3.0 Tesla MRI compared with 1.5 Tesla.

Maas M, Lambregts DM, Lahaye MJ, Beets GL, Backes W, Vliegen RF, Osinga-de Jong M, Wildberger JE, Beets-Tan RG - Abdom Imaging (2012)

Bottom Line: Intra-observer agreement was κ 0.71 at 1.5T and 0.76 at 3T.This is the first study to compare 3T with 1.5T MRI for T-staging of rectal cancer within the same patients.Larger studies are needed to acknowledge these findings.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Maastricht University Medical Center, AZ, The Netherlands.

ABSTRACT

Objectives: Magnetic resonance imaging (MRI) is not accurate in discriminating T1-2 from borderline T3 rectal tumors. Higher resolution on 3 Tesla-(3T)-MRI could improve diagnostic performance for T-staging. The aim of this study was to determine whether 3T-MRI compared with 1.5 Tesla-(1.5T)-MRI improves the accuracy for the discrimination between T1-2 and borderline T3 rectal tumors and to evaluate reproducibility.

Methods: 13 patients with non-locally advanced rectal cancer underwent imaging with both 1.5T and 3T-MRI. Three readers with different expertise evaluated the images and predicted T-stage with a confidence level score. Receiver operator characteristics curves with areas under the curve (AUC) and diagnostic parameters were calculated. Inter- and intra-observer agreements were calculated with quadratic kappa-weighting. Histology was the reference standard.

Results: Seven patients had pT1-2 tumors and six had pT3 tumors. AUCs ranged from 0.66 to 0.87 at 1.5T vs. 0.52-0.82 at 3T. Mean overstaging rate was 43% at 1.5T and 57% at 3T (P = 0.23). Inter-observer agreement was κ 0.50-0.71 at 1.5T vs. 0.15-0.68 at 3T. Intra-observer agreement was κ 0.71 at 1.5T and 0.76 at 3T.

Conclusions: This is the first study to compare 3T with 1.5T MRI for T-staging of rectal cancer within the same patients. Our results showed no difference between 3T and 1.5T-MRI for the distinction between T1-2 and borderline T3 tumors, regardless of expertise. The higher resolution at 3T-MRI did not aid in the distinction between desmoplasia in T1-2-tumors and tumor stranding in T3-tumors. Larger studies are needed to acknowledge these findings.

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A, B A small vessel penetrating the bowel wall is depicted in more detail on the 3T image (A) than on the 1.5T image (B). This could lead to more interpretation difficulties and thus overstaging of T2 tumors.
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Fig4: A, B A small vessel penetrating the bowel wall is depicted in more detail on the 3T image (A) than on the 1.5T image (B). This could lead to more interpretation difficulties and thus overstaging of T2 tumors.

Mentions: The inter-observer agreement was lower at 3T MRI compared to 1.5T MRI, which indicates higher degrees of uncertainty between readers. This may have been caused by the more detailed depiction of the tumor and of the normal anatomy. Improved visibility at 3T MRI of small vessels penetrating the rectal wall may cause more interpretation difficulties (Fig. 4A, B). Increased variation between readers just by chance would be less likely because of the relatively high intra-observer agreement at both field strengths, although tested in only one of the readers (reader 2). We believe that the solid intra-observer agreement at both field strengths can be explained by the type of case mix that reader 2 is exposed to in the referral hospital, which had resulted in a stable and consistent learning curve, making him more flexible to handle different and new techniques.Fig. 4


T-staging of rectal cancer: accuracy of 3.0 Tesla MRI compared with 1.5 Tesla.

Maas M, Lambregts DM, Lahaye MJ, Beets GL, Backes W, Vliegen RF, Osinga-de Jong M, Wildberger JE, Beets-Tan RG - Abdom Imaging (2012)

A, B A small vessel penetrating the bowel wall is depicted in more detail on the 3T image (A) than on the 1.5T image (B). This could lead to more interpretation difficulties and thus overstaging of T2 tumors.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3345180&req=5

Fig4: A, B A small vessel penetrating the bowel wall is depicted in more detail on the 3T image (A) than on the 1.5T image (B). This could lead to more interpretation difficulties and thus overstaging of T2 tumors.
Mentions: The inter-observer agreement was lower at 3T MRI compared to 1.5T MRI, which indicates higher degrees of uncertainty between readers. This may have been caused by the more detailed depiction of the tumor and of the normal anatomy. Improved visibility at 3T MRI of small vessels penetrating the rectal wall may cause more interpretation difficulties (Fig. 4A, B). Increased variation between readers just by chance would be less likely because of the relatively high intra-observer agreement at both field strengths, although tested in only one of the readers (reader 2). We believe that the solid intra-observer agreement at both field strengths can be explained by the type of case mix that reader 2 is exposed to in the referral hospital, which had resulted in a stable and consistent learning curve, making him more flexible to handle different and new techniques.Fig. 4

Bottom Line: Intra-observer agreement was κ 0.71 at 1.5T and 0.76 at 3T.This is the first study to compare 3T with 1.5T MRI for T-staging of rectal cancer within the same patients.Larger studies are needed to acknowledge these findings.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Maastricht University Medical Center, AZ, The Netherlands.

ABSTRACT

Objectives: Magnetic resonance imaging (MRI) is not accurate in discriminating T1-2 from borderline T3 rectal tumors. Higher resolution on 3 Tesla-(3T)-MRI could improve diagnostic performance for T-staging. The aim of this study was to determine whether 3T-MRI compared with 1.5 Tesla-(1.5T)-MRI improves the accuracy for the discrimination between T1-2 and borderline T3 rectal tumors and to evaluate reproducibility.

Methods: 13 patients with non-locally advanced rectal cancer underwent imaging with both 1.5T and 3T-MRI. Three readers with different expertise evaluated the images and predicted T-stage with a confidence level score. Receiver operator characteristics curves with areas under the curve (AUC) and diagnostic parameters were calculated. Inter- and intra-observer agreements were calculated with quadratic kappa-weighting. Histology was the reference standard.

Results: Seven patients had pT1-2 tumors and six had pT3 tumors. AUCs ranged from 0.66 to 0.87 at 1.5T vs. 0.52-0.82 at 3T. Mean overstaging rate was 43% at 1.5T and 57% at 3T (P = 0.23). Inter-observer agreement was κ 0.50-0.71 at 1.5T vs. 0.15-0.68 at 3T. Intra-observer agreement was κ 0.71 at 1.5T and 0.76 at 3T.

Conclusions: This is the first study to compare 3T with 1.5T MRI for T-staging of rectal cancer within the same patients. Our results showed no difference between 3T and 1.5T-MRI for the distinction between T1-2 and borderline T3 tumors, regardless of expertise. The higher resolution at 3T-MRI did not aid in the distinction between desmoplasia in T1-2-tumors and tumor stranding in T3-tumors. Larger studies are needed to acknowledge these findings.

Show MeSH
Related in: MedlinePlus