Thumb Injuries and Instabilities. Part 2: Spectrum of Lesions.

The motor function of the thumb and its alignment with regard to the hand make it particularly vulnerable to trauma. Pathology encountered in this joint is varied, and imaging techniques play a crucial role in the diagnosis and characterization of injury. Despite advances in imaging technology, acute thumb injuries remain a challenge for radiologists. Currently, standard radiography and ultrasonography are frequently used first-line imaging techniques. Computed tomography is most often indicated for complex fractures and dislocations. Magnetic resonance imaging may be used to optimally characterize soft tissues and bone marrow. In this article, we cover the most common traumatic injuries: fractures, dislocations, collateral ligament injuries of the metacarpophalangeal joint, as well as soft tissue lesions.

Thumb Injuries and Instabilities. Part 1: Anatomy, Kinesiology, and Imaging Techniques of the Thumb.

The unique anatomical characteristics of the thumb offer a broad range of motion and the ability to oppose thumb and finger, an essential function for grasping. The motor function of the thumb and its orientation make it particularly vulnerable to trauma. Pathologic lesions encountered in this joint are varied, and imaging techniques play a crucial role in injury detection and characterization. Despite advances in diagnostic accuracy, acute thumb injuries pose a challenge for the radiologist. The complex and delicate anatomy requires meticulous and technically flawless image acquisition. Standard radiography and ultrasonography are currently the most frequently used imaging techniques. Computed tomography is most often indicated for complex fractures and dislocations, and magnetic resonance imaging may be useful in equivocal cases. In this article, we present the relevant anatomy and imaging techniques of the thumb.

CT angiography and MRI of hand vascular lesions: technical considerations and spectrum of imaging findings.

Vascular lesions of the hand are common and are distinct from vascular lesions elsewhere because of the terminal vascular network in this region, the frequent hand exposure to trauma and microtrauma, and the superficial location of the lesions. Vascular lesions in the hand may be secondary to local pathology, a proximal source of emboli, or systemic diseases with vascular compromise. In most cases, ischaemic conditions are investigated with Doppler ultrasonography. However, computed tomography angiography (CTA) or dynamic contrast-enhanced magnetic resonance angiography (MRA) is often necessary for treatment planning. MR imaging is frequently performed with MRA to distinguish between vascular malformations, vascular tumours, and perivascular tumours. Some vascular tumours preferentially affect the hand, such as pyogenic granulomas or spindle cell haemangiomas associated with Maffucci syndrome. Glomus tumours are the most frequent perivascular tumours of the hand. The purpose of this article is to describe the state-of-the-art acquisition protocols and illustrate the different patterns of vascular lesions and perivascular tumours of the hand.

Pathologic conditions of the hypothenar eminence: evaluation with multidetector CT and MR imaging.

Pain, weakness, and sensory loss occur frequently in the hypothenar eminence. However, clinical examination is difficult and nonspecific, and the prescribed imaging technique may be inadequate, or images may be misinterpreted. Different imaging modalities have various degrees of usefulness for the diagnosis of painful pathologic conditions of the hypothenar eminence. Radiography, multidetector computed tomography (CT), multidetector CT arthrography, and magnetic resonance (MR) imaging of the wrist are useful for surveying the anatomy of the hypothenar eminence, the Guyon canal, and the ulnar nerve and artery and for determining the cause of pain or other symptoms. A fracture of the pisiform bone or the hook of the hamate bone, osteoarthritis or osteochondromatosis of the pisotriquetral joint, Guyon canal syndrome, hypothenar hammer syndrome, tendinopathy of the flexor carpi ulnaris, an anomalous muscle, a ganglion cyst, or a tumor may be responsible for ulnar neuropathy. Specific radiographic views, such as the semisupinated oblique view and the lateral view with the hand radially deviated and the thumb abducted, often provide a sufficient basis for the diagnosis of acute fracture of the hook of the hamate or the pisiform bone. Multidetector CT angiography is an efficient method for diagnosing hypothenar hammer syndrome, and multidetector CT arthrography is well suited for evaluation of the pisotriquetral joint. MR imaging is the modality of choice for depiction of the ulnar nerve.

Imaging of diaphragmatic injury: a diagnostic challenge?

Diaphragmatic injuries occur in 0.8%-8% of patients after blunt trauma. Although the diagnosis may be obvious at standard chest radiography or computed tomography (CT) in most situations, some more subtle signs require careful analysis of CT images and examination with magnetic resonance (MR) imaging in some specific situations. Each method of imaging evaluation has advantages and pitfalls according to the type of diaphragmatic rupture. MR imaging with breath-hold acquisition permits good visualization of diaphragmatic abnormalities, but this technique cannot be performed in emergency situations. Because of a dramatic reduction in motion and beam-hardening artifacts and significant improvement of spatial resolution, especially along the z axis, helical CT and multisection CT allow better demonstration of the most subtle signs, such as a focal indentation of the liver or a right-sided collar sign. In addition, helical CT and multisection CT are useful tools in the evaluation of patients with multiple traumatic injuries.