MR microscopy of the human finger and correlation with histology—a proof‐of‐principle study

Abstract

Magnetic resonance imaging (MRI) with small surface coils is a well established method for the diagnostic evaluation of finger masses. Until now, histological examination has been required to reliably assess tumor extent and infiltration of surrounding structures. Ultra-high-field MR microscopy (MRM) allows evaluation of anatomical structures and pathologies with submillimeter resolution. This study describes the diagnostic prospects and potential of MRM based on the ex-vivo examination of different finger pathologies. Ten human digits were examined by ex-vivo MRM at 7.1 Tesla (ClinScan, Bruker BioScan) using a T2-weighted turbo spin echo (TSE) sequence. Imaging parameters were: TE 48 ms; TR 8370 ms; slice thickness 700 µm; matrix size 1024 × 1024 pixels; FOV 37 × 37 mm; in-plane resolution 36 × 36 µm/voxel. Afterwards specimens were examined histologically. Histology and MRM were correlated. MRM allowed evaluation of the anatomy of the nail, the tendon insertions, the distal interphalangeal joint, and the neurovascular bundles. Finger abnormalities evaluated by MRM included osteomyelitis and metastatic disease. Subsequent histological examination confirmed MRM findings regarding origin, internal makeup, and extent of the structures visualized. This study demonstrates the potential of MRM for imaging small anatomical structures and pathologies of the human finger. Our ex-vivo findings correlate strongly with histology, suggesting that MRM may gain a central role in assessing anatomical structures and pathology in terms of morphology, extent, and infiltration of surrounding structures. Therefore, with increasing availability, MRM is expected to become an essential tool not only in experimental studies but also for daily routine.

MR microscopy of the human fetal upper extremity – a proof-of-principle study

“…The present study shows that MRM of the upper human extremity is feasible in the late embryonic and early fetal period and correlates well with conventional histology. We achieved an in-plane resolution of 20 × 20 μm and a slice thickness of 70 μm, which is better than in previous reports [ 8 , 12 ].…”

“…However, current knowledge relies on early descriptive studies in human, experimental studies in laboratory animals, and histological work-up of embryos [ 2 , 5 – 7 ]. Ultra-high field MRI with improved spatial resolution of less than 100 μm is known as MR microscopy (MRM) [ 8 , 10 , 12 ]. The present study shows that MRM of the upper human extremity is feasible in the late embryonic and early fetal period and correlates well with conventional histology.…”

“…Magnetic resonance imaging (MRI) provides excellent soft tissue contrast with high resolution and has multiplanar imaging capability [ 8 ]. Furthermore, it is a well-established technique for prenatal imaging, e.g., the detection of fetal brain abnormalities in utero [ 9 ].…”

“…Furthermore, it is a well-established technique for prenatal imaging, e.g., the detection of fetal brain abnormalities in utero [ 9 ]. Ultra-high field magnetic resonance microscopy (MRM) allows acquisition of MR images with submillimeter spatial resolution [ 8 , 10 ]. Taking the upper extremity as an example, this study explores the potential of MRM for the assessment of the development of the fetal upper extremity and discusses its correlation with histological findings.…”

In vivo MRI of the human finger at 7 T

“…Few MRI experiments showed nervous structures, in particular Pacinian corpuscles in vivo in the fingertip at 1.5 T and in the toe at 3 T . In a cadaver study, 76 µm in‐plane MRI images of the fingertip acquired in a small‐bore 7T‐scanner have been demonstrated and correlated with histology .…”