Cartilage magnetic resonance imaging techniques at 3 T: current status and future directions

Diffusion-weighted MR imaging of musculoskeletal tissues: incremental role over conventional MR imaging in bone, soft tissue, and nerve lesions

Diffusion-weighted imaging is increasingly becoming popular in musculoskeletal radiology for its incremental role over conventional MR imaging in the diagnostic strategy and assessment of therapeutic response of bone and soft tissue lesions. This article discusses the technical considerations of diffusion-weighted imaging, how to optimize its performance, and outlines the role of this novel imaging in the identification and characterization of musculoskeletal lesions, such as bone and soft tissue tumors, musculoskeletal infections, arthritis, myopathy, and peripheral neuropathy. The readers can use the newly learned concepts from the presented material containing illustrated case examples to enhance their conventional musculoskeletal imaging and interventional practices and optimize patient management, their prognosis, and outcomes.

Spectrum of common and uncommon causes of knee joint hyaline cartilage degeneration and their key imaging features

Hyaline cartilage lining the surfaces of diarthrodial joints is an important construct for transmission of load and to reduce friction between the bones. Normal wear and tear accounts for about 3-5 percent knee cartilage loss ever year in otherwise healthy people after the age of 30 years. Several conditions and diseases lead to premature cartilage degeneration. Standardized description of cartilage loss, detailed evaluation of the joint health and determining the underlying etiology of cartilage loss are important for effective reporting, multidisciplinary communications and patient management. In this article, the authors discuss normal and abnormal imaging appearances of the hyaline cartilage of knee with focus on using controlled terminology and MRI classifications. The reader will benefit and learn key MR imaging features of a spectrum of common and uncommon conditions and diseases affecting the knee cartilage, such as trauma, secondary injury associated with meniscus and ligament injury related instability, arthritis, ischemia, idiopathic, and hereditary conditions including Matrix metalloproteinase-2 (MMP-2) mutations and mucopolysaccharidosis type IX disease with illustrative case examples.

Conventional and novel imaging modalities in osteoarthritis: current state of the evidence

PURPOSE OF REVIEW

Imaging modalities are currently an inseparable part of osteoarthritis diagnosis. In this review, we describe the current state of evidence regarding conventional and novel imaging modalities in evaluation of osteoarthritis. Modalities including radiography (qualitative and semi-quantitative assessments), ultrasonography, computed tomography [CT; conventional multidetector CT (MDCT), cone-beam CT (CBCT) and four-dimensional CT (4DCT)], MRI (MRI; semi-quantitative, quantitative and compositional) and PET and their applications are reviewed.

RECENT FINDINGS

Radiography is the modality of choice for initial assessment of osteoarthritis. However, due to its low sensitivity and specificity, numerous recent investigations have proposed MRI as a powerful addition to detect and grade osteoarthritis features, which are not apparent in radiography. Semi-quantitative MRI measurements are feasible to perform in routine clinical practice. Quantitative and compositional MRI measurements have extended the amount of information an MRI examination can provide regarding the three-dimensional shape and tissue composition of articular cartilage. 4DCT and CBCT are introduced as imaging examinations that may reveal biomechanical cartilage abnormalities in osteoarthritis joint by dynamic and weight-bearing evaluations, respectively. Recent PET studies may unveil the underlying metabolic activities that can be associated with osteoarthritis.

SUMMARY

In addition to the established role of radiographs, MRI is the advanced modality of choice for detection and quantification of various osteoarthritis features. 4DCT and CBCT may have specified applications when diagnosis of underlying motion abnormality or dynamic changes in weight-bearing situation is suspected. Future studies should elucidate the specific clinical applications of ultrasonography and PET.