High-Resolution Microscopy-Coil MR Imaging of Skin Tumors: Techniques and Novel Clinical Applications

Abstract

High-resolution magnetic resonance (MR) imaging performed with a microscopy coil is a robust radiologic tool for the evaluation of skin lesions. Microscopy-coil MR imaging uses a small surface coil and a 1.5-T or higher MR imaging system. Simple T1- and T2-weighted imaging protocols can be implemented to yield high-quality, high-spatial-resolution images that provide an excellent depiction of dermal anatomy. The primary application of microscopy-coil MR imaging is to delineate the deep margins of skin tumors, thereby providing a preoperative road map for dermatologic surgeons. This information is particularly useful for surgeons who perform Mohs micrographic surgery and in cases of nasofacial neoplasms, where the underlying anatomy is complex. Basal cell carcinoma is the most common nonmelanocytic skin tumor and has a predilection to manifest on the face, where it can be challenging to achieve complete surgical excision while preserving the cosmetic dignity of the patient. Microscopy-coil MR imaging provides dermatologic surgeons with valuable preoperative anatomic information that is not available at conventional clinical examination.

MR-Eye: High-Resolution Microscopy Coil MRI for the Assessment of the Orbit and Periorbital Structures, Part 1: Technique and Anatomy

“…This high SNR is maintained down to the orbital apex, beyond which signal loss becomes an issue and supplementary head coil imaging may be required. As we have previously described for the imaging of nasofacial lesions, 2 we use a 40-mm-internal-diameter small-loop radiofrequency receiver coil with a 1.5T MR imaging unit (Magnetom Avanto; Siemens, Erlangen, Germany). This has 32 receiver channels and SQ-engine gradients (maximum gradient field strength, 45 mT/m; slew rate, 200 T/m/s).…”

“…I maging of orbital and periorbital structures and pathologies presents challenges due to the various limitations intrinsic to ultrasound, CT, and conventional MR imaging. 1,2 Management of structural pathology in and around the orbit is guided by knowledge of the compartments involved and the tissue of origin. 3 Both the initial surgical approach 4 and subsequent reconstruction techniques are influenced by factors that can only be resolved at a very small scale, sometimes at submillimeter resolution.…”

“…We have previously described the application of MC-MR imaging in preoperative planning for Mohs micrographic surgery for nasofacial skin neoplasms. 2 Collaboration with ophthalmic surgeons has extended our practice to provide high-resolution imaging of the orbits and surrounding structures. Figure 1 demonstrates the striking difference in image resolution between conventional head coil orbital MR imaging and MC-MR imaging.…”

Invited Commentary: The Rise of Microradiology

“…The article by Budak et al (1) describes the use of microscopy-coil MR imaging of skin for preoperative guidance in resection of BCC. This approach allows accurate preoperative staging of BCC.…”

“…In fact, optical coherence tomography routinely provides images of the retinal nerve layers with 10-μm resolution, albeit with limited imaging depth (Fig 2). Computed tomography as currently used in clinical practice allows high spatial resolution, although the tissue contrast may not be sufficient to make the fine distinctions noted by Budak et al (1). Computed tomography as currently used in clinical practice allows high spatial resolution, although the tissue contrast may not be sufficient to make the fine distinctions noted by Budak et al (1).…”