Hand and finger structures have an intricate anatomy and are frequently injured in everyday activities and sports. ^,, The fine anatomy of the hand and finger tendons, pulleys, cartilage, and synovial linings, and so forth requires high-resolution imaging for accurate diagnosis, since clinical examination is often challenging and diagnostically inaccurate due to similar presentations of different pathologies affecting these areas. While ultrasound provides high spatial resolution and real-time evaluation, MR imaging offers superior soft tissue imaging contrast and affords simultaneous assessment of both osseous and soft tissue structures. Conventional 2 dimensional (2D) MR imaging has been traditionally used for hand and finger imaging and is useful for various pathologies, like tumors, infections, and fractures. However, the ability of 2D MR imaging in evaluating fine or subtle internal derangements may be limited due to thick slices with large interslice gaps, which lead to decreased sensitivity and specificity. A potential alternative is 3 dimensional (3D) spin-echo MR imaging, which is now possible with high (0.5–0.8 mm) isotropic imaging resolution that allows multiplanar tissue plane-specific reconstructions. This article details the role of 3D MR imaging of the hand and fingers and compares it to 2D MR imaging.

The human hand is uniquely adapted for both strength and precision, requiring significant mobility for effective finger and thumb positioning, yet sufficient strength for grasping and delicacy for fine motor tasks. The hand comprises of 19 bones. Five metacarpal bones form the palm, articulating with each finger and the thumb at the metacarpophalangeal (MCP) joints. Each metacarpal bone features a head (proximal to the knuckle), shaft, and base (proximal at the wrist). Fingers consist of 3 phalanges (proximal, middle, and distal), which are connected by 2 interphalangeal (IP) joints, the proximal interphalangeal (PIP) joint and the distal interphalangeal (DIP) joint. The thumb uniquely has 2 phalanges and 1 IP joint. The wrist contains 8 carpal bones arranged in 2 rows. The proximal row, located dorsally near the forearm, includes the scaphoid, lunate, triquetrum, and pisiform. The distal row, closer to the palm, comprises the trapezium, trapezoid, capitate, and hamate. The wrist is formed by the articulation of the radius with the scaphoid and lunate.

The carpal tunnel is a narrow fibro-osseous passage bounded by the pisiform, hamate, scaphoid, and trapezium bones and covered by the transverse carpal ligament. It facilitates the passage of 9 tendons, 4 ligaments, and the median nerve from the forearm into the hand.

Collateral ligaments are situated on either side of each finger and thumb MCP and IP joints, preventing abnormal sideways movement. The volar plates are strong ligament, which connect the phalanges at palmar aspects of the MCP, PIP and DIP joints and prevent hyperextension during joint extension.

Each hand contains 34 intrinsic muscles. The thenar eminence controls thumb movement and includes 5 muscles: the interosseous, adductor pollicis, flexor pollicis longus (FPL), abductor pollicis brevis, and opponens pollicis. The adductor pollicis inserts on the ulnar sesamoid of the thumb, while the radial sesamoid anchors the abductor and opponens pollicis. The FPL tendon courses between these muscles and through the sesamoid interspace. The hypothenar eminence, located along the palm’s ulnar edge by the fifth digit, contains 3 muscles: abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi. These originate from the pisiform or hook of the hamate and control fifth digit abduction, flexion, and rotation toward the palm. The interossei, situated between the metacarpals, are responsible for finger abduction and adduction, comprising 4 dorsal and 3 palmar muscles. The 4 lumbricals originate from the radial side of the flexor digitorum profundus (FDP) tendons and insert into the radial side of the extensor expansions, flexing the MCP joints and extending the IP joints. ^,,

The extensor tendons facilitate finger extension. They originate from the posterior forearm muscles, cross the dorsum of the wrist, and continue into the fingers, forming a flattened extensor hood at the MCP joint, stabilized by sagittal bands. The extensor mechanism fans out to attach to the phalanges: the central slip inserts onto the base of the middle phalanx, while the terminal tendon, formed by the fusion of 2 lateral tendons, inserts onto the base of the distal phalanx. Intertendinous connections, or juncturae tendinum, link adjacent extensor tendons over the dorsum of the hand, helping coordinate finger extension and providing additional stabilization. Contraction of extensor muscles pulls the tendon, straightening the finger. Flexor tendons, originating from forearm muscles, enable finger and thumb flexion. These tendons pass through the carpal tunnel and palm, bifurcating into 2 per finger. The flexor digitorum superficialis (FDS) attaches to the middle phalanx, flexing the MCP and PIP joints. The FDP inserts onto the distal phalanx, flexing the MCP, PIP, and DIP joints. These tendons are maintained close to the bones by a system of flexor pulleys. In the thumb, the FPL originates in the forearm and attaches to the distal phalanx, while the flexor pollicis brevis originates in the wrist and connects to the proximal phalanx. The flexor and extensor tendons of the hand are divided into 5 and 8 zones, respectively, based on their functional significance and implications for clinical management ^, ( Tables 1 and 2 ).

Sensation and motor function of the hand are controlled by the radial, median, and ulnar nerves. The radial nerve courses along the radial side of the forearm, innervating the dorsal surface of the hand from the thumb to the third finger, including portions of the dorsal ring and middle fingers. The median nerve traverses the carpal tunnel and provides sensation to the thumb, index, middle, and half of the ring finger, as well as motor supply to the thenar muscles, except for the adductor pollicis brevis and deep head of the flexor pollicis brevis (which are innervated by the deep branch of the ulnar nerve). The ulnar nerve passes through Guyon’s canal, formed by the pisiform and hamate bones, where it divides into its main terminal branches, the superficial ulnar nerve supplying sensation to the little finger and half of the ring finger, and the deep ulnar nerve innervating many of the small intrinsic muscles of the hand including thumb adductors.

MR imaging of the hand and fingers is commonly indicated for evaluating pain, swelling, injury, or limited range of motion. Underlying etiologies may include collateral ligament injuries, tendon and pulley injuries, osteochondral injury, and volar plate lesions. With its excellent soft tissue contrast and multiplanar, multiparametric imaging capabilities, MR imaging facilitates accurate localization and detailed characterization of abnormalities within this small and complex anatomy.

Using dedicated multichannel surface coils, high-quality images can be obtained using scanners at or greater than 1.5 T (Tesla). A combination of a strong gradient system with a small field of view (FOV) and thin slices improves spatial resolution with optimal signal-to-noise ratio (SNR) while reducing scan time. A small FOV (8–12 cm), matrix size of greater than 256 to 320, and 3 mm slice thickness with 10% gap are standard for optimal 2D imaging that allows in-plane resolution of 0.4 to 0.8 mm.

Patients are commonly positioned supine with the arm adducted close to the hip in mild supination. While the prone (superman) position (arm overhead, elevated, and elbow pronated) may offer advantages in fat saturation and reducing coil shine artifacts due to the hand being iso-centered within the magnet. Routine MR imaging of the hand and finger is performed in axial, sagittal, and coronal planes. Hand orientation in scans is typically in relation to the long axis of the third metacarpal of individual digits, depending on the area of interest, with finger orientation in relation to the MCP and PIP joints of the extended finger.

Generally, for internal derangements, one can obtain proton density-weighted (PDW) with or without fat suppression in axial and coronal planes. These are supplemented by T1-weighted (T1W) and fat-suppressed (fs) T2-weighed (T2W) or short tau inversion recovery (STIR) images for bone marrow assessment. Recently, intermediate-weighted T2W Dixon images have become available that produce several maps, including in-phase (IP), opposed-phase, and water images in similar resolution as PDW and fsPDW, obviating multiple sequence acquisitions in the same plane. In our practice, 3 plane simultaneous multislice acquisition T2 Dixons (SMS Dixon) in axial, coronal, and sagittal planes suffice for routine hand and wrist imaging. T1W and STIR images are added to infection, vascular malformation, and tumor protocols. The use of gadolinium contrast with T1W Dixons aids in the diagnosis and activity of arthritis, infection, and tumor pathology, and so forth. ^,,

Three-dimensional MR imaging has become a transformative tool in musculoskeletal imaging, providing isotropic resolution, multiplanar reformatting, and comprehensive assessment of fine musculoskeletal structures. Unlike 2D MR imaging, which allows simultaneous multislice acquisition, isotropic volumetric 3D MR imaging sequences capture the entire volume in a single acquisition, with voxel dimensions equal in all 3 spatial directions—typically between 0.5 and 0.8 mm. This enables high-resolution imaging in any structural plane (axial, sagittal, coronal, curved, or oblique) without loss of image quality during reconstruction, offering flexibility for detailed diagnostic evaluation and for presurgical planning.

When combined with acceleration techniques, such as fast parallel imaging, scan times are significantly reduced to within 3 to 4 minutes. Compressed sensing or fast parallel imaging leverages mathematical reconstruction algorithms to produce high-quality images from undersampled data by exploiting the inherent sparsity of medical images. This approach maintains diagnostic image quality while shortening scan times, thus minimizing motion artifacts, and improving patient comfort. Advanced fat-saturation methods like Dixon and spectral attenuated inversion recovery (SPAIR) ensure uniform suppression across the FOV.

For imaging of the hand and fingers, the most commonly used sequences are 3D FSE or turbo spin-echo (TSE) sequences, marketed under names such as CUBE (GE, Waukesha, Wisconsin, USA), SPACE (Siemens, Erlangen, Germany), and VISTA (Philips, Best, Netherlands). These sequences are ideal for visualizing small ligaments, flexor pulleys, extensor mechanisms, and joint cartilage in structure specific planes. ^, While in-plane resolution of 3D MR imaging (0.7 mm) is slightly lower than 2D MR imaging, nongap volume imaging avoids partial volume artifacts, this producing real-black signal of normal or intact ligaments and connective tissue structures from the adjacent soft tissue edema or granulation tissue. Postcontrast 3D spoiled gradient-echo sequences like volume interpolated breath hold examination (VIBE) or VIBE-DIXON in 1.0 to 2.0 mm isotropic resolution are often employed to assess synovitis, tenosynovitis, or enhancing soft tissue lesions or tumors ( Figs. 1 and 2 ). These 3D Dixon-based sequences enhance fat suppression and are effective for evaluating marrow and soft tissue abnormalities. Since 3D sequences are quick, one can obtain perfusion imaging using 3D MR angiogram with sparse k-sampling volume acquisitions (like TRICKS-Time resolved imaging of contrast kinetics, TWIST- time-resolved angiography with interleaved stochastic trajectories, and 4D TRAK- Time-Resolved MR Angiography With Keyhole—different vendor-specific names) for the first 3 minutes using 10 seconds per frame with subtraction, maximum intensity projections (MIPs), and cine manipulations. The remaining 3 minutes are used for delayed postcontrast imaging using VIBE/VIBE Dixon with multiplanar constructions. Such postprocessed MIP images allow full extent of lesion detection by enhancing image signal and quality due to summation of SNR and contrast-to-noise ratio ( Fig. 3 ). These advantages render 3D MR imaging a powerful tool that can supplement or even replace conventional 2D sequences in routine clinical imaging for various pathologies. While gradient-echo based or steady state sequence-based alternatives are available like dual echo steady state (DESS), these are less desirable as compared to FSE variants due to superior resolution of the latter ( Fig. 4 ).

Active morphea-related synovitis and tenosynovitis—3D T1W FSE imaging of the hand: Contrast-enhanced sagittal ( A ), coronal ( B ), and axial ( C ) 3D T1W reconstructions reveal diffuse articular enhancements ( long arrows ) and tendon sheath synovial enhancements ( short arrows ) in this case of morphea.

Wrist-predominant rheumatoid arthritis (RA): Contrast-enhanced 3D T1W FSE imaging with coronal ( A ), sagittal ( B ), and axial ( C ) reconstructions display marrow edema of wrist bones ( short arrows ) and synovial thickening and enhancement ( long arrows ).

Wrist-predominant rheumatoid arthritis (RA): Three-dimensional time-resolved MR angiography with perfusion imaging: Coronal dynamic contrast-enhanced T1W FSE images of the hand ( A–C ) and respective MIP imaging ( D ) shows patent tortuous vessels and wrist synovitis with early arrival of contrast and persistence on delayed imaging.

High-resolution 3D MR imaging: The bone-on-bone osteoarthritis of the radiocarpal joint ( arrow ) detected on radiograph ( A ) is adequately depicted on the coronal 3D PDW FSE reconstruction ( C ), compared to less well depiction of 3D DESS image ( B ) ( arrows ). Also note better assessment of complete scapholunate tear on 3D PDS FSE ( small arrow ).