Limits...
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.

Show MeSH

Related in: MedlinePlus

Stranding (arrows) around a pT2 tumor which cannot be distinguished from tumor extension in a T3 tumor (left 1.5T and right 3T).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3345180&req=5

Fig3: Stranding (arrows) around a pT2 tumor which cannot be distinguished from tumor extension in a T3 tumor (left 1.5T and right 3T).

Mentions: Our finding that 3T is not better than 1.5T MRI for T2 vs. T3 differentiation might be surprising; nevertheless, it could be explained given the fact that with MR the differentiation between T1-2 and T3 tumors is associated with interpretation difficulties in the distinction between desmoplastic benign reactions in a T2 tumor and malignant tumor stranding in a T3 tumor (Fig. 3). This results in substantial overstaging errors in this group of borderline tumors, confirming the findings of other authors [18, 22]. Overstaging rates at 1.5T MRI are reported to range from 25% to 46% [9]. In our study at 1.5T, overstaging occurred in 29%–57%, slightly higher figures than in the literature because of our study population, with mainly patients with borderline T1-2 and T3 tumors. At 3T, it was higher ranging from 43% to 86%. This confirms the hypothesis that despite the inherent higher resolution and the more detailed depiction of the rectal wall, 3T does not help us to obtain a better performance because the interpretation difficulties of desmoplastic reactions with or without tumor cells remain.Fig. 3


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)

Stranding (arrows) around a pT2 tumor which cannot be distinguished from tumor extension in a T3 tumor (left 1.5T and right 3T).
© Copyright Policy
Related In: Results  -  Collection

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

Fig3: Stranding (arrows) around a pT2 tumor which cannot be distinguished from tumor extension in a T3 tumor (left 1.5T and right 3T).
Mentions: Our finding that 3T is not better than 1.5T MRI for T2 vs. T3 differentiation might be surprising; nevertheless, it could be explained given the fact that with MR the differentiation between T1-2 and T3 tumors is associated with interpretation difficulties in the distinction between desmoplastic benign reactions in a T2 tumor and malignant tumor stranding in a T3 tumor (Fig. 3). This results in substantial overstaging errors in this group of borderline tumors, confirming the findings of other authors [18, 22]. Overstaging rates at 1.5T MRI are reported to range from 25% to 46% [9]. In our study at 1.5T, overstaging occurred in 29%–57%, slightly higher figures than in the literature because of our study population, with mainly patients with borderline T1-2 and T3 tumors. At 3T, it was higher ranging from 43% to 86%. This confirms the hypothesis that despite the inherent higher resolution and the more detailed depiction of the rectal wall, 3T does not help us to obtain a better performance because the interpretation difficulties of desmoplastic reactions with or without tumor cells remain.Fig. 3

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