7-tesla MR imaging of non-melanoma skin cancer samples: correlation with histopathology.

PURPOSE

The aims of this study were to compare in vitro magnetic resonance imaging (MRI) characteristics of keratinocytic skin cancer assessed by a 7-tesla (T) MRI with histopathology, and to describe MRI features of skin tumors.

METHODS

This prospective study included 30 skin tumors treated by surgery. MR images of skin samples were acquired on a 7-T MR scanner using a fast spin-echo T(2)-weighted and an isotropic 3D gradient-echo T(1)-weighted sequence. Length, width, Breslow index and margins of the lesions were measured. The presence or absence of the following was noted: healthy margins, ulceration of the dermis, in situ lesions, superficial and deep dermis involvement, subcutaneous involvement, superficial and intratumoral keratin. MR results were compared to histopathology.

RESULTS

Interclass correlation coefficient (ICC) was very good for the evaluation of the width (ICC = 0.86) and Breslow index (ICC = 0.87). The ICC was good for the evaluation of the margins (ICC = 0.70) but for length, ICC was lower (ICC = 0.67). Mean bias between MRI and histopathology was inferior to 1 mm for width, Breslow index and margin.

CONCLUSION

In vitro 7-T MRI of keratinocytic skin cancer allows delineation of lesions with good correlation with histopathology. After in vivo confirmation it could have a diagnostic role regarding the delineation of surgical margins but its actual limitations prevent its practical adoption at this time.