Glenohumeral instability: evaluation using MR arthrography of the shoulder

In the setting of glenohumeral instability or when internal derangement of the shoulder joint is suspected, MR arthrography has been demonstrated to be an accurate diagnostic imaging technique. Knowledge of the complex anatomy of the shoulder and its variations is essential in order to maximize diagnostic accuracy. Received: 24 February 1999 Revision requested: 19 April 1999 Revision received: 12 May 1999 Accepted: 13 May 1999     

Magnetic resonance imaging findings in anterolateral impingement of the ankle

Objective. To demonstrate the MR imaging findings of anterolateral impingement (ALI) of the ankle. Design and patients. Nine patients with a history of ankle inversion injury and chronic lateral ankle pain were imaged with MR imaging, and the findings correlated with the results of arthroscopy. Three additional patients with clinically suspected ALI of the ankle were also included. Ankle MR imaging studies from 20 control patients in whom ALI was not suspected clinically were examined for similar findings to the patient group. Results. MR imaging findings in the patients with ALI included a soft tissue signal mass in the anterolateral gutter of the ankle in 12 of 12 (100%) cases, corresponding to the synovial hypertrophy and soft tissue mass found at arthroscopy in the nine patients who underwent arthroscopy. Disruption, attenuation, or marked thickening of the anterior talofibular ligament was seen in all cases. Additional findings included signs of synovial hypertrophy elsewhere in the tibiotalar joint in seven of 12 patients (58%) and bony and cartilaginous injuries to the tibiotalar joint in five of 12 (42%). None of the control patients demonstrated MR imaging evidence of a soft tissue mass in the anterolateral gutter. Conclusions. ALI of the ankle is a common cause for chronic lateral ankle pain. It has been well described in the orthopedic literature but its imaging findings have not been clearly elucidated. The MR imaging findings, along with the appropriate clinical history, can be used to direct arthroscopic examination and subsequent debridement. Received: 22 July 1999 Revision requested: 20 September 1999 Revision received: 7 October 1999 Accepted: 8 October 1999     

Radiography in osteoarthritis of the knee

Osteoarthritis (OA) is a multifactorial process affecting cartilage and subchondral bone. Conventional radiographs are inexpensive and readily available. The increased knowledge with regard to interpreting weightbearing radiographs of the tibiofemoral joint and axial radiographs of the patellofemoral joint will enable these examinations to remain competitive techniques compared with more expensive and sophisticated methods, such as MR imaging, when investigating knee pain to establish the diagnosis and the severity of OA. Received: 21 May 1999 Revision requested: 13 July 1999 Revision received: 9 August 1999 Accepted: 12 August 1999     

Magnetic resonance imaging of congenital abnormalities of the thoracic aorta

This article outlines the ability of MR imaging in the detection and presurgical evaluation of congenital abnormalities of the thoracic aorta (CATA). Congenital abnormalities of the thoracic aorta may be found incidentally on chest radiographs in patients without symptoms, or it can be associated with clinical findings which are very variable depending on the association with congenital cardiac malformations or vascular ring. When CATA is suspected as the cause of anomalies in the mediastinum in asymptomatic patients, confirmation of the abnormality should be by MR imaging allowing precise evaluation of the thoracic aorta and origin of the principal arteries. When CATA is considered because clinical findings indicate coarctation of the aorta, vascular ring or associated cardiac disorder, evaluation with ultrasound can be complemented by MR, which in most cases will replace the diagnostic catheterization. Received 2 April 1997; Revision received 14 July 1997; Accepted 12 September 1997     

Isolated penile metastasis from bladder carcinoma

Metastases of the penis are uncommon, with only approximately 300 cases reported since 1870. In up to 70 % of patients, the primary tumour is located in the urogenital tract. Furthermore, isolated metastases of the penis are exceptionally rare. We report a case of solitary squamous cell metastasis of the penis presenting with painful swelling initially thought to be inflammatory in origin. The CT and MR imaging findings are presented with a short review of the literature. Received: 22 September 1998; Revision received: 19 January 1999; Accepted: 12 February 1999     

MR imaging of brachial plexopathy in breast cancer patients without palpable recurrence

Objective. To investigate the role of MR imaging in detecting brachial plexus (BP) abnormalities in breast cancer patients with plexopathy but without palpable masses. Design. MR imaging of the BP was performed on 26 breast cancer patients with brachial plexopathy without palpable regional masses, using 0.5 T and 1.5 T imaging systems. Findings were correlated with the clinical diagnoses. Patients. Twenty-six patients with brachial plexopathy and history of breast cancer were enrolled in the study. All patients presented with plexopathy symptoms. Fourteen patients were positive and 12 patients were indeterminate for BP metastasis according to clinical criteria. Results and conclusion. MR imaging demonstrated masses involving the BP representing metastases in two patients. Nine patients had other regional abnormalities with a normal brachial plexus. It is concluded that MR imaging is useful in the assessment and direction of therapy of brachial plexopathy in breast cancer patients by detecting both metastases to the BP as well as other abnormalities, unrelated to the BP, which may explain the patient’s symptoms. Received: 29 September 1999 Revision requested: 22 January 1999 Revision received: 23 March 1999 Accepted: 6 April 1999     

Evaluation of the postoperative meniscus of the knee: a study comparing conventional arthrography, conventional MR imaging, MR arthrography with iodinated contrast material, and MR arthrography with gadolinium-based contrast material

Objective. To compare four imaging methods in the evaluation of the postoperative meniscus: conventional arthrography, conventional MR imaging, MR arthrography with iodinated contrast material, and MR arthrography with gadolinium-based contrast material. Design and patients. Thirty-three patients referred for knee MR examinations with a history of meniscal surgery were studied prospectively. At the first patient visit, conventional MR examination was followed by an MR arthrogram with gadolinium-based contrast material. At the second visit, a conventional arthrogram with iodinated contrast material was followed immediately by an MR examination. Imaging examinations were interpreted by a masked reader, and then compared with the results of repeat arthroscopic surgery in 12 patients. Results. The correct evaluation of the status of postoperative menisci was allowed in 12 of 13 patients (92%) by MR arthrography using gadolinium-based contrast agent, 10 of 13 patients (77%) by conventional MR examination, 9 of 12 patients (75%) by MR arthrography, and 7 of 12 patients (58%) by conventional arthrography. Conclusion. Intra-articular fluid is advantageous in the evaluation of patients with a suspected meniscal retear. MR arthrography with gadolinium-based contrast material is the most accurate imaging method for the diagnosis of meniscal retears. Received: 7 April 1999 Revision requested: 26 May 1999 Revision received: 17 June 1999 Accepted: 18 June 1999     

Marginal erosive discovertebral ”Romanus” lesions in ankylosing spondylitis demonstrated by contrast enhanced Gd-DTPA magnetic resonance imaging

Objective. To assess the value of Gd-DTPA magnetic resonance (MR) imaging in the demonstration of marginal destructive discovertebral Romanus lesions in ankylosing spondylitis. Design and patients. A prospective study of Gd-DTPA MR imaging was performed in 39 patients with a clinical diagnosis of ankylosing spondylitis and typical Romanus lesions seen on radiographs of the thoracolumbar spine. MR morphological appearances and signal intensity changes at the discovertebral junctions were analysed and compared with the radiographic findings. Results. Ninety-nine discovertebral junctions with Romanus lesions showed low signal intensity on T1-weighted and high signal on T2-weighted and T1-weighted postcontrast images at the vertebral corners consistent with oedematous hyperaemic inflammatory tissue. There were nine discovertebral junctions with similar MR findings but normal radiographs. Fifty-three discovertebral junctions showed syndesmophyte formation with increased signal intensity on both T1- and T2-weighted images with no contrast enhancement. Sixty-five discovertebral junctions showed a mixture of radiographic features and varied high and low signal changes at the vertebral rim on MR imaging with rims of enhancement in the vertebral body following contrast administration. Conclusion. Gd-DTPA MR imaging demonstrates a variable signal pattern and degree of contrast enhancement which may reflect the evolutionary stages of discovertebral enthesitis in ankylosing spondylitis. MR imaging may identify early erosive changes in radiographically normal vertebra. The role of MR imaging needs further investigation. Received: 6 April 1998 Revision requested: 7 May 1998 Revision received: 26 October 1999 Accepted: 27 October 1999     

Penile epithelioid sarcoma: MR imaging findings

Magnetic resonance imaging findings of a 38-year-old man with epithelioid sarcoma of the penis is presented. It started as a firm, painless and slowly growing nodule at the base of his penis 6 months previously which caused pain radiating to the testis during coitus. It has been well known that sarcomas may well mimic reactive processes. Initial presentation of epithelioid sarcoma may provoke considerable diagnostic difficulty, and its differentiation from benign lesions, such as Peyronie's disease and chronic inflammation, may be a clinical problem. In our present report the MR findings are compared with those of the epithelioid sarcomas of various locations reported in the literature and differential diagnosis of the entity is discussed. To our knowledge, this is the first report regarding the MR findings of the epithelioid sarcoma of penis. Received: 15 September 1998; Revision received: 22 December 1998; Accepted: 20 January 1999     

Desmoplastic fibroma of bone: MRI features

Desmoplastic fibroma of bone is a very rare benign tumor, which may be locally aggressive. In contrast to the well-documented radiological appearance, the literature on MR imaging features of this tumor is scarce. The MR imaging characteristics in our case are compared to those previously reported. Although there is a considerable overlap in the MR imaging features with other bone tumors, an interesting MR feature of desmoplastic fibroma is the presence of low to intermediate signal intensity foci on T2-weighted images, which radiographically does not correspond to calcifications. This feature may help narrow the differential diagnosis. Received: 24 May 1999 Revision requested: 30 June 1999 Revision received: 8 October 1999 Accepted: 14 October 1999     

MR imaging after therapeutic injection of the subacromial bursa

Objective. As a therapeutic injection into the subacromial bursa (SAB) is commonly performed for impingement syndrome, it is important to know whether this fluid can be retained for a period of time and cause confusion with a pathologic collection of fluid. This study identifies and describes the appearance of recent subacromial injection using MR imaging, and the appearance of a potential complication. Design and patients. Fourteen asymptomatic shoulders were studied with MR imaging using fast spin echo T2-weighted imaging (1.5 T) prior to injection with 7 cm³ of xylocaine. Four shoulders had subacromial fluid and were eliminated from the study. The remaining 10 (9 men, 1 woman; age range 27–36 years, average age 33 years) were then re-imaged immediately, and at 6, 12 and 24 h after the injection or until fluid resolved. Each set of images was reviewed for the presence of fluid in the SAB and for additional abnormalities. Results. Fluid was identified in all subjects in the SAB in the immediate, 6 and 12 h post-injection images. At 24 h, fluid was not identified within the SAB in eight of 10 patients. In one patient fluid resolved in 48 h. The other continued to demonstrate fluid in the SAB and in the joint as well as abnormal signal in the infraspinatus muscle from a presumed myositis. Imaging was performed up to 10 days after the injection in this patient. Conclusions. It is known that fluid identified in the SAB without evidence of a cuff tear may be due to bursitis. However, if MR imaging is performed within 24 h of injection, the presence of the fluid may be iatrogenic. In addition, the history of recent therapeutic injection is very important as complications such as myositis can occur as a result of the injection. Knowledge of injection prior to imaging is vital for accurate interpretation of MR shoulder examinations. Received: 14 May 1999 Revision Requested: 22 July 1999 Revision Received: 11 August 1999 Accepted: 18 August 1999     

Diffusion-weighted imaging of the musculoskeletal system in humans

This article reviews the principles of diffusion-weighted imaging (DWI) and recent results in DWI of the musculoskeletal system. The potential of DWI in the diagnosis of pathology of the musculoskeletal system is discussed. DWI is a relatively new MR imaging technique that has already been established in neuroradiology, especially in the early detection of brain ischemia. The random motion of water protons on a molecular basis can be measured with DWI. To date DWI of the abdomen and of the musculoskeletal system has only been employed in scientific studies, but first results indicate that it may also be beneficial in these fields. Different diffusion characteristics have been found in normal tissues such as muscle, fat and bone marrow. Also, pathologic entities such as neoplasms, post-therapeutic soft tissue changes and inflammatory processes can be differentiated. Normal muscle shows significantly higher diffusion values than subcutaneous fat and bone marrow, due to a higher mobility of water protons within muscle. Soft tissue tumors exhibit a significantly lower diffusion value compared with post-therapeutic soft tissue changes and inflammatory processes. Necrotic tumor tissue can be distinguished from viable tumor due to significantly higher diffusion of water protons within necrotic tissue. Received: 10 February 2000 Revision requested: 4 April 2000 Revision received: 10 May 2000 Accepted: 12 May 2000     

Primary hemangiopericytoma of the tibia: MR and angiographic correlation

The Magnetic Resonance Imaging (MRI) appearances of primary osseous hemangiopericytoma (HPC) have been rarely described. We report on a 46-year-old Chinese man with primary osseous HPC of the right tibia. The characteristic vascular distribution of this tumor, presenting with a ”spoke-wheel” appearance on MR images and with angiographic correlation, is described. Although not pathognomonic, this MR appearance may be an important finding in suggesting the diagnosis of osseous HPC. Received: 3 March 1999 Revision requested: 26 April 1999 Revision received: 13 September 1999 Accepted: 15 September 1999     

Progressive destructive vertebral sarcoid leading to surgical fusion

Skeletal sarcoidosis is rare. This report describes a 31-year-old African American man who presented with a destructive osteolytic lesion of C2 and another lesion in a rib. The lesion at C2 was treated with corpectomy and bone graft. Four months later the lesion recurred and a new lesion was discovered in the cervical vertebral column. The patient declined surgery for instability for another 3 months, choosing to remain in a halo. Seven months following the initial operation, a technetium bone scan showed spread of the disease to the calvarium and thoracic and lumbar vertebrae. The patient had no symptoms referable to these sites. The patient agreed to have his neck fused at this point. For the next 10 months, the patient was on steroids and a further new lesion appeared at L5 without localizing signs or symptoms. The patient declined further evaluation over the next 12 months and is now considered lost to follow-up. Received: 29 July 1999 Revision requested: 26 August 1999 Revision received: 1 September 1999 Accepted: 2 September 1999     

Indirect wrist MR arthrography: the effects of passive motion versus active exercise

Purpose.In the wrist, to determine whether passive motion or active exercise yields a better indirect MR arthrographic effect following intravenous gadolinium administration. Design and patients. Twenty-six consecutive patients were studied by indirect wrist MR arthrography. In half active exercise and in half passive motion was performed. Four regions of interest were studied including the distal radioulnar joint, the radiocarpal joint, the midcarpal joint, and the triangular fibrocartilage. Ranges and means of signal intensity were calculated. Surgical follow-up was performed in 22 patients. Results. The joint fluid intensity was greatest in the distal radioulnar joint. Fluid signal intensity was greater and more consistent in the passive motion group although the results did not achieve statistical significance. Imaging accuracy appeared similar in the two groups and was excellent for the triangular fibrocartilage (100%) and scapholunate ligaments (96%). Conclusion. Active exercise and passive motion yield similar degrees of wrist arthrographic effect, but the effect of passive motion is somewhat more consistent. Preliminary data show good accuracy for internal derangements. Received: 4 June 1999 Revision requested: 6 August 1999 Revision received: 14 September 1999 Accepted: 20 September 1999     

Sports-related muscle injuries of the lower extremity: MR imaging appearances

Sports-related injuries of the lower extremity are frequent. Before magnetic resonance (MR) imaging was available, ultrasound, radionuclide scintigraphy and computed tomography were used to evaluate muscle trauma. Although relatively inexpensive, these imaging modalities are limited by their low specificity. The high degree of soft tissue contrast and multiplanar capability of MR imaging, allow direct visualization as well as characterization of traumatic muscle lesions. This pictorial review highlights the spectrum of traumatic muscle lesions on MRI, with emphasis on its typical appearances. Received: 8 May 1998; Revision received: 31 August 1998; Accepted: 23 September 1998     

Benign vascular lesions of bone: radiologic and pathologic features

 The benign vascular tumors of bone represent a diverse group of tumors that can present with a broad spectrum of clinical signs and symptoms. They can also present a significant diagnostic challenge due to their widely variable radiographic imaging and histologic features. Some of the tumors manifest as clearly benign lesions with tissue-specific diagnostic imaging features, while others have non-specific imaging features that may simulate malignant neoplasm. This article will provide a review of the nomenclature and the characteristic radiographic and pathologic features of the benign vascular lesions of bone. The information will aid in improving our diagnostic accuracy and enhance our understanding of the biologic potential of this diverse group of osseous lesions. Received: 14 May 1999 Revision requested: 17 June 1999, 6 October 1999 Revision received: 27 October 1999 Accepted: 27 October 1999     

Disorders of the hallux sesamoid complex: MR features

Numerous painful conditions can affect the first metatarsophalangeal-sesamoid joint complex. Symptoms can be of sudden or insidious onset, and be of acute or chronic duration. Although conventional radiography is recognized as the initial diagnostic procedure for these symptoms, there is often a need to proceed to MR imaging. MR imaging is sensitive and can be utilized in the investigation of the hallux sesamoid complex to differentiate soft tissue from osseous pathology. Synovitis, tendonitis, and bursitis can be distinguished from bony abnormalities such as sesamoid fracture, avascular necrosis, and osteomyelitis. An understanding of MR imaging features and techniques will result in the highest diagnostic yield. Early and accurate diagnosis of sesamoid complex disorders can guide the physician to the appropriate clinical management and prevent potentially harmful longstanding joint dysfunction.     

Radiology of the spleen

The spleen is generally not considered a challenge to the radiologist. Most often it poses a problem by anomalies or an irregular but normal contrast enhancement; however, a variety of inflammatory, infectious and neoplastic diseases may involve the spleen. CT and ultrasonography are screening modalities for the spleen. For problem solving, MR imaging can be helpful, especially due to its free choice of the imaging plane and because of the high resolution in contrast MR imaging. Splenic angiography as a diagnostic tool has generally been replaced by CT, ultrasound, or MR and is now used as an interventional method, e. g., in non-surgical management of patients with chronic idiopathic thrombocytopenia or in patients with splenic trauma. This article reviews the radiology of the spleen, including anatomy, embryology, splenomegaly, splenic injury, infarction, cysts, tumors, abscesses, sarcoidosis, and AIDS. Knowledge about the use of different imaging modalities and underlying gross and microscopic pathologic features leads to a better understanding of the radiologic findings. Received: 4 November 1999 Revised: 12 May 2000 Accepted: 16 May 2000     

Reactive synovitis of the knee joint: MR imaging appearance with arthroscopic correlation

Objective. To evaluate the use of routine MR imaging sequences in detecting and characterizing secondary reactive synovitis of the knee joint using arthroscopy as the standard of reference. Design and patients. Fifty consecutive patients with a history of knee pain who were referred for MR imaging and subsequently underwent arthroscopy of the knee comprised the study group. MR images were evaluated for the presence and appearance of synovitis reflected in synovial thickening and irregularity. Synovial thickening was graded on MR imaging as follows: 0=normal, 1=thin line of increased signal intensity, 2=increased signal intensity with frond-like or hair-like projections and a granular appearance of joint fluid. Standard knee imaging protocols were used. Results. The sensitivity, specificity, and accuracy of MR imaging in detecting synovitis compared with arthroscopy were 88%, 97%, and 95%, respectively. Grade 1 synovitis was best seen on proton-density-weighted images, demonstrating increased signal intensity of the synovium against the relatively low signal intensity of the joint fluid. Grade 2 synovitis was best seen on proton-density images and T2-weighted spin echo and fast spin echo images with fat saturation, demonstrating a granular and linear hair-like appearance of joint fluid. Axial and sagittal imaging planes were most helpful in the diagnosis of synovitis. Conclusion. Routine MR pulse sequences are useful in identifying the presence and extent of synovial abnormalities. The detection of different stages of synovial pathology should become an important part of the evaluation of the post-traumatic patient as treatment may be altered as a result. Received: 17 March 2000 Revision requested: 5 May 2000 Revision received: 8 June 2000 Accepted: 8 June 2000