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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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Related in: MedlinePlus

An intact hypo-intense line (arrows) is seen surrounding the tumor, which indicates that the muscularis propria is intact (1.5T image). Therefore, the tumor is confined to the bowel wall (pT1-2).
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Fig5: An intact hypo-intense line (arrows) is seen surrounding the tumor, which indicates that the muscularis propria is intact (1.5T image). Therefore, the tumor is confined to the bowel wall (pT1-2).

Mentions: The highest overstaging rate was found in the reader from a non referral center (86% at 3T). The fact that this reader reads rectal MRI on a less frequent basis than the others might explain the inferior results compared to the others. This trend may be even aggravated by the more detailed depiction at 3T MRI which can lead to more interpretation difficulties in the less experienced reader in particular. The PPV for staging of T2 tumors with MRI is known to be high [23], because the existence of a hypo-intense bowel wall on T2W FSE sequences (Fig. 5) is a reliable predictive criterion for a tumor limited to the bowel wall. Yet this sign is subject to some learning curve. Therefore, readers from a referral center are more confident to identify a tumor that is restricted to the bowel wall based on this bowel wall sign.Fig. 5


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)

An intact hypo-intense line (arrows) is seen surrounding the tumor, which indicates that the muscularis propria is intact (1.5T image). Therefore, the tumor is confined to the bowel wall (pT1-2).
© Copyright Policy
Related In: Results  -  Collection

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

Fig5: An intact hypo-intense line (arrows) is seen surrounding the tumor, which indicates that the muscularis propria is intact (1.5T image). Therefore, the tumor is confined to the bowel wall (pT1-2).
Mentions: The highest overstaging rate was found in the reader from a non referral center (86% at 3T). The fact that this reader reads rectal MRI on a less frequent basis than the others might explain the inferior results compared to the others. This trend may be even aggravated by the more detailed depiction at 3T MRI which can lead to more interpretation difficulties in the less experienced reader in particular. The PPV for staging of T2 tumors with MRI is known to be high [23], because the existence of a hypo-intense bowel wall on T2W FSE sequences (Fig. 5) is a reliable predictive criterion for a tumor limited to the bowel wall. Yet this sign is subject to some learning curve. Therefore, readers from a referral center are more confident to identify a tumor that is restricted to the bowel wall based on this bowel wall sign.Fig. 5

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