High-field MR surface-coil imaging of the hand and wrist. Part I. Normal anatomy

High-resolution magnetic resonance (MR) images of the hands and wrists of six healthy volunteers were obtained at 1.5 T with a surface coil. Additionally, the hands and wrists of two fresh cadavers were imaged and were subsequently sectioned for anatomic correlation. High contrast when depicting soft-tissue, coupled with impressive spatial resolution and multiplanar capabilities, enabled delineation of fine structures including nerves, tendons, and blood vessels. Osseous and cartilaginous structures were also well depicted. MR imaging gives anatomic definition of the hand and wrist unmatched by other diagnostic imaging methods.     

Normal MR imaging anatomy of the wrist and hand

MR imaging is widely used in the evaluation of internal derangement of joints. In the past, the use of hand and wrist MR imaging lagged behind imaging of larger joints,largely because of technical limitations of spatial resolution and signal-to-noise ratio when imaging the small anatomic structures. However, with recent technical advances in extremity coil design, MR imaging has provided us with new insights into the difficult anatomy of the wrist by allowing improved visualization of the relationship of the muscles, ligaments, tendons, and bone. Although the limits of spatial resolution afforded by specialized surface coils and signal processing methods may not have yet been completely realized at 1.5 Tesla, the potential for significant improvements in hand and wrist imaging is likely to rest with the advent of higher strength magnets.     

Masses of the hand and wrist: detection and characterization with MR imaging

To assess the value of MR imaging in the detection, delineation, and characterization of mass lesions of the hand and wrist, we reviewed the MR imaging findings of 38 patients referred for evaluation of such lesions. Twenty-five patients had a palpable mass. In an additional 13 patients an occult mass lesion was suspected as the cause of distal ulnar neuropathy. Twenty-two mass lesions (16 benign and six malignant) were detected by MR. All were correctly predicted to be benign or malignant. In nine (56%) of the 16 benign mass lesions, the specific diagnosis was suggested. In the remaining seven benign mass lesions and in the six malignant tumors, the MR findings were not specific enough to permit a diagnosis. Of the 14 patients referred for evaluation of a distal ulnar neuropathy, an occult ganglionic cyst compressing the ulnar nerve was revealed with MR imaging in three. MR imaging of the hand and wrist is accurate in the detection of mass lesions and can correctly distinguish benign from malignant tumors in the majority of cases. Specific diagnoses can be made in certain benign lesions. Occult mass lesions can be confirmed or excluded as the cause of distal ulnar neuropathy with MR imaging.     

CT and MR imaging of the central skull base. Part 2. Pathologic spectrum

The radiologist must have a thorough knowledge of the normal anatomy and the pathologic spectrum of the skull base to determine the extent of abnormality and to help plan the surgical approach. The authors describe and present examples of congenital, benign, and malignant lesions that affect this region, including cephalocele, fracture, fistula, juvenile angiofibroma, meningioma, chordoma, pituitary adenoma, chondrosarcoma, nasopharyngeal carcinoma, and rhabdomyosarcoma. Metastatic, infectious, and other miscellaneous processes are also discussed. Imaging strategies with computed tomography and magnetic resonance imaging to aid in the diagnosis are suggested.     

High-field MR imaging of extracranial hematomas

The MR features of 20 extracranial hematomas studied on a 1.5-T system and imaged with both short repetition-time/echo-time (TR/TE) and long TR/TE pulse sequences were reviewed. In four of five acute hematomas (those less than 7 days of age), signal intensity was markedly decreased on long TR/TE images and was either intermediate or slightly decreased on short TR/TR images. Fourteen subacute hematomas (7 days to 7 weeks of age) and one chronic hematoma (9 months) were studied. The appearance of the subacute lesions varied from intermediate to high intensity on short TR/TE sequences, but all demonstrated increased signal on long TR/TE sequences. A low-signal rim was noted at the margin of nine subacute lesions. In one patient with this finding, pathologic examination showed that the low-signal margin corresponded to a region containing hemosiderin-laden macrophages at the periphery of the hematoma. These results correlate well with those reported for intracranial hematomas examined at this field strength. We conclude that analysis of signal-intensity patterns at 1.5 T is useful in staging the evolution of hematomas.     

Enhanced MR imaging of tenosynovitis of hand and wrist in inflammatory arthritis

Objective The purpose of this study is to describe the appearance of tenosynovitis in various tendon groups in the wrist and hand and to compare MR enhanced and non-enhanced imaging evaluation of tenosynovitis of hand and wrist in inflammatory arthritis.Design and patients We reviewed 72 MRI studies of hands and wrists, including coronal, axial and sagittal images in 30 consecutive patients with inflammatory arthritis and tenosynovitis. We compared the degree of synovitis on T2-weighted vs contrast-enhanced T1-weighted images, using a predetermined scale. We also measured the extent of tenosynovitis in three dimensions. The tendons were assigned to volar, dorsal, ulnar and radial groups in the wrist and to extensor, flexor and thumb groups in the hand. Degree of tenosynovitis (graded 0–3), cross-sectional area and volume of the inflamed synovium in various tendon groups were then compared by statistical analysis.Results Review of the medical records revealed the following diagnoses in our patient population: rheumatoid arthritis (n=16), unspecified inflammatory polyarthritis (n=9), psoriatic arthritis (n=2), CREST syndrome (n=1), systemic lupus erythematosus (n=1), paraneoplastic syndrome with arthritis (n=1). The average T2 brightness scores and post-gadolinium enhancement scores were 1.0 and 1.7, respectively (P<0.001) in the wrist studies. The average T2 brightness scores and post-gadolinium enhancement scores were 0.7 and 1.4, respectively (P<0.001) in the hand studies. The average sensitivity of T2-weighted imaging for detection of tenosynovitis was 40% in the hand and 67% in the wrist tendons, when contrast-enhanced images were used as a reference. Carpal tunnel flexor tendons were the most frequently affected tendons of the wrist. The most frequently affected tendons of the hand were second and third flexor tendons. The hand flexors demonstrated higher degrees of enhancement and larger volumes of the inflamed tenosynovium than did the hand extensors and tendons of the thumb.Conclusion Enhanced MR imaging of the hand and wrist is a superior technique for detection of tenosynovitis. We observed carpal tunnel flexor tendons to be the most frequently affected tendons of the wrist. The flexor tendons of the second and third digits were the most frequently affected tendons of the hands. Higher contrast-enhancement scores and inflammation were noted in the hand flexor than in the extensor tendons.     

Urinary bladder MR imaging. Part II. Neoplasm

The potential of magnetic resonance (MR) imaging for the evaluation and staging of bladder tumors was analyzed in 15 patients (11 cases of transitional cell carcinoma, two adenocarcinomas, one leiomyosarcoma, and one leiomyoma). Neoplasms were characterized by size, site, and growth pattern, and the accuracy of the staging was compared with the results of computed tomography and pathologic study. Malignancies were accurately detected and staged by MR imaging in 12 of 14 patients (85%). Tumor site and degree of bladder distention did not adversely affect detection; tumors greater than 1.5 cm were detected easily. In situ carcinoma (stage Tis) was not detected on MR images. Imaging in both sagittal and transverse planes was needed for optimal bladder evaluation. Bladder carcinoma was best displayed with a short echo delay time (TE) of 28 msec and repetition (TR) times of 1.0-2.0 sec: TR = 1.0 gave 34% contrast and TR = 2.0 gave 36% contrast between tumor and surrounding urine. Bladder-wall invasion by tumor was best evaluated with long TR (2.0 sec) and long TE (56 msec) (82% contrast). For assessing tumor extension into perivesical fat, short TR (0.5 sec) and TE (28 msec) were optimal (58% contrast). MR imaging offers an increased sensitivity for tumor detection and promises to greatly improve the staging of bladder neoplasms.     

MR imaging of the knee. Part II. Chronic disorders

Sixty patients with symptoms of chronic disease of the knee joint were evaluated with high-resolution, thin-section magnetic resonance (MR) imaging. MR imaging depicted a wide variety of knee joint abnormalities including osteochondritis dissecans, medullary infarcts, epiphyseal osteonecrosis, intraarticular osteochondral fragments, synovial cysts, joint effusions, intraarticular soft-tissue tumors, synovial disease, leukemic infiltration of bone marrow, Osgood-Schlatter disease, and nonossifying fibroma. In two cases MR imaging depicted bone infarcts not seen on both radionuclide bone scans and standard radiographs. The highly detailed depiction of the articular cartilage was of particular importance in predicting arthroscopic findings in cases of osteochondritis dissecans. In two cases, a soft-tissue mass (pigmented villonodular synovitis) and a large osteochondral fragment undetected at arthroscopy were accurately localized with MR imaging. The results indicate that MR imaging is capable of providing information that might otherwise require multiple, sometimes invasive diagnostic procedures.     

MR imaging: Arthropathies and infectious conditions of the elbow, wrist, and hand

The superior soft tissue contrast and multiplanar capability of MR imaging has contributed to earlier diagnosis and implementation of effective treatment for a variety of arthropathies and infectious conditions of the elbow, wrist, and hand. Because of overlapping clinical signs and symptoms, MR imaging plays an important role in delineating the features and staging of each of these conditions. This article discusses the seropositive and seronegative inflammatory arthropathies, with emphasis on early detection and surveillance, as well as gout, synovial osteochondromatosis, pigmented villonodular synovitis, tenosynovitis, and de Quervain's tenosynovitis. Certain noninflammatory arthritides and infectious conditions are also reviewed.     

Athletic injuries of the wrist and hand. Part I: traumatic injuries of the wrist

Hand and wrist injuries in sports are some of the most common injuries reported. This review discusses briefly the causes of hand and wrist injuries in sports and discusses pertinent biomechanical findings regarding the range of motion required in different sports activities. The bulk of the review discusses specific traumatic and overuse injuries to the hand and wrist commonly seen in the athlete. Emphasis is placed on problematic traumatic injuries such as carpal scaphoid fractures and hook of the hamate fractures, as well as ligament injuries to the wrist with regard to diagnosis, treatment, and return to athletic competition.     

Preoperative evaluation of cervical radiculopathy and myelopathy by surface-coil MR imaging

During a 2-year period, 256 patients were screened for cervical radiculopathy and myelopathy with surface-coil MR images and plain films. Selected patients had follow-up examinations including CT, myelography, and CT myelography. Thirty-four of these patients underwent cervical spine surgery after MR imaging, which disclosed a total of 50 abnormalities in three major categories: herniated disks, bony canal stenoses, and intradural lesions. MR correctly predicted 88% of all surgically proved lesions compared with 81% for CT myelography, 58% for myelography, and 50% for CT. Missed herniated disks on either MR or CT myelography usually were the result of technically suboptimal studies caused by motion artifacts on MR and beam-hardening artifacts on CT myelography. Small osteophytes adjoining herniated disks sometimes were not predicted on MR, although such osteophytes invariably were seen on plain films and were palpable during standard anterior cervical diskectomy procedures. Herniated disks in the lateral root canals found in two patients appeared to be detected more readily by CT myelography than by MR. All proved lesions were detected by either screening MR images and plain films or by follow-up CT myelograms. MR replaced invasive evaluations by myelography and CT myelography in 32% of preoperative patients. We conclude that MR images, combined with plain films, offer an accurate, noninvasive test for the preoperative evaluation of cervical radiculopathy and myelopathy, while CT myelography is the preferred follow-up examination.     

Neck neoplasms: MR imaging. Part II. Posttreatment evaluation

Thirty-three patients who had undergone prior surgery and/or radiation therapy for malignant neoplasms of the neck were studied with magnetic resonance (MR) imaging. Twenty-seven of these patients were also evaluated with computed tomography (CT). Ten patients were healthy posttreatment volunteers, and 23 had documented tumor recurrence. MR images better demonstrated normal muscular landmarks, especially in patients with obliterated fat planes. Areas of posttreatment fibrosis or scarring were low in signal intensity with all MR pulse sequences. However, in three patients, high signal intensity from postradiation edema of the supraglottic area mimicked neoplasm. In patients with recurrent tumor, MR imaging was superior to CT in defining the relationship of tumor and muscle and in demonstrating vascular anatomy when no intravenous contrast material was given during the CT examination. In two patients tumor and fibrosis were separated on MR images because of signal intensity differences. CT scans, however, showed adjacent bone and cartilage anatomy better. Our data indicate that an MR examination may be helpful in patients in whom CT is indeterminate either because of anatomical distortion or suboptimal demonstration of vascular anatomy.     

Vagina: evaluation with MR imaging. Part II. Neoplasms

The potential of magnetic resonance (MR) imaging in the detection of vaginal tumors and the assessment of their extent was evaluated retrospectively in 87 patients in whom primary, metastatic, or recurrent vaginal cancer was clinically suspected. MR findings were compared with the results of surgery and/or biopsy. Results of histopathologic study verified a normal vagina in 51 patients, benign cysts in two, primary tumor in four, metastatic cancer in 22, and recurrent tumor in eight. MR imaging demonstrated the two benign cysts, correctly depicting their size and location, and demonstrated and enabled correct staging of the four primary tumors. MR accuracy for demonstrating metastatic cancer was 92%, sensitivity was 95%, and specificity was 90%. Tumor extension to the vagina was reliably excluded (negative predictive value = 97%), but false-positive interpretations occurred (positive predictive value = 84%) primarily because inflammation (n = 2) and congestion (n = 2) could not be distinguished from tumor invasion. An additional role of MR imaging was the ability to differentiate tumor from fibrotic tissue in patients with suspected recurrent vaginal carcinoma. The overall accuracy of MR imaging for recurrent vaginal cancer was 82% (14 of 17).