Solitary infantile myofibromatosis involving the clavicle

A rare case of solitary infantile myofibromatosis of bone is reported in the right clavicle of a 15-year-old boy. A radiograph demonstrated an osteolytic lesion with a sharp margin and a sclerotic rim. CT revealed a circumscribed lesion with slight expansion of the cortex. On MRI the lesion appeared isointense to muscle on T1-weighted images, bright on T2-weighted images, and showed marked gadolinium enhancement. The patient was well, without evidence of recurrence or metastasis, 4 years and 5 months following resection. Received: 11 August 1998 Revision requested: 5 October 1998, 18 March 1999 Revision received: 15 March 1999, 23 April 1999 Accepted: 28 April 1999     

Solitary myofibromatosis of the skull

We present a case of solitary infantile myofibromatosis of the skull in a 3-month-old boy. A right parietal subcutaneous lump was found at birth, and it increased in size over the ensuing 3 months. Surgery was performed, and a diagnosis of myofibromatosis was confirmed histopathologically. Solitary myofibromatosis of the skull is extremely rare. The radiographical, CT, and MR appearances, as well as histopathological findings, are described in this article. Received: 30 December 1998; Revised: 21 April 1999; Accepted: 11 May 1999     

Skeletal muscle lymphoma: observations at MR imaging

 We present the MR appearances of three patients with biopsy-proven primary lymphoma of skeletal muscle. In each case lymphoma resulted in bulky expansion of the involved muscle, homogeneously isointense to skeletal muscle on T1-weighted images, homogeneously hyperintense to skeletal muscle on T2-weighted images and diffusely enhancing following intravenous administration of gadopentate dimeglumine.     

CT and MR imaging of the “target sign” in metastatic brain disease

The “target sign” is a common finding in granulomatous infection. A case with the target sign in metastatic brain tumor from small cell lung carcinoma is reported. Received: 28 September 1998; Revised: 15 March 1999; Accepted: 15 April 1999     

Repeated quantitative perfusion and contrast permeability measurement in the MRI examination of a CNS tumor

This study reports on the results of quantitative MRI perfusion and contrast permeability measurement on two occasions in one patient. The measurements were separated 81 days in time. The tumor grew considerably in this period, but no change was found with respect to perfusion and contrast permeability. Non-involved white matter values were reproduced to demonstrate repeatability. The presented approach to dynamic susceptibility contrast MRI allows fast and repeatable quantitative assessment of perfusion and is easily integrated in a conventional brain tumor protocol. Received: 25 January 2000; Accepted: 28 January 2000     

Vertebral arch or posterior spinal tuberculosis

 Posterior spinal tuberculosis or arch tuberculosis is a form of skeletal tuberculosis that selectively involves the vertebral arch. It may mimic skeletal neoplasm clinically and radiographically. Although posterior spinal tuberculosis has been reported in developing countries it has rarely been found in the United States. As a result, there is limited information about this entity in the US literature. We are presenting our experience in a patient born in the United States.     

Utility of MR arthrography in the diagnosis of adhesive capsulitis

Objective. Arthrographically, adhesive capsulitis is characterized by decreased joint volume; histologically, the capsule and synovium are thickened. We therefore compared using MR arthrography the joint volumes and capsule/synovial thickness of patients with and without adhesive capsulitis in order to assess the utility of MR arthrography in diagnosing adhesive capsulitis. Design and patients. The 1.5 T MR arthrography images of 28 subjects with (n=9) and without (n=19) adhesive capsulitis were compared. Adhe- sive capsulitis was diagnosed when there was an injected glenohumeral joint volume of less than 10 ml. Two masked observers working in consensus assessed the images for the relative amount of fluid in the biceps tendon sheath and axillary recess, corrugation at the margin of the capsule, capsule/synovial thickness, abnormalities of the rotator interval capsule, and for the presence of a cuff tear. Results. There was a trend towards differences in capsular and synovial thickness (P>0.07) between the subjects with and without adhesive capsulitis; however, the controls had thicker synovium/capsules. Surprisingly, the amount of fluid in the axillary recess and biceps tendon sheath was not significantly different between the groups (P>0.25). There were more tears of the rotator cuff in controls than in patients with adhesive capsulitis (6, 3 vs 1, 1: complete, partial). Also, both corrugation (7 vs 0) and interval abnormalities (7 vs 0) were more common in the controls. Conclusion. There appear to be no useful MR arthrographic signs of adhesive capsulitis. Capsular/synovial thickness, static fluid volume, and the presence of corrugation are inconclusive as MR arthrographic signs for distinguishing shoulders with adhesive capsulitis from those without. Received: 1 June 2000 Revision requested: 11 September 2000 Revision received: 13 November 2000 Accepted: 27 November 2000     

MR imaging of the Achilles tendon: overlap of findings in symptomatic and asymptomatic individuals

Objective: To differentiate MR imaging characteristics of symptomatic as compared with asymptomatic Achilles tendons. Design: 1.5 T MR images of 94 feet (88 patients) with ”abnormal” MR examinations were retrospectively evaluated and clinically correlated. Two masked, independent observers systematically evaluated for intratendon T2 signal, tendon thickness, presence of peritendonitis, retrocalcaneal bursal fluid volume, pre-Achilles edema, bone marrow edema at the Achilles insertion, and tears (interstitial, partial, complete). These findings were correlated with symptoms (onset and duration) and physical examination results (tenderness, palpable defects, increased angle of resting dorsiflexion). Results: Of the 94 ankles, 64 ankles (32 females, 29 males) were clinically symptomatic. No relationship between Achilles tendon disorders and age or gender was identified. Asymptomatic Achilles tendons frequently demonstrated mild increased intratendon signal (21/30), 0.747 cm average tendon thickness, peritendonitis (11/30), pre-Achilles edema (12/30), and 0.104 ml average retrocalcaneal bursal fluid volume. Symptomatic patients had thicker tendons (0.877 cm), greater retrocalcaneal fluid volume (0.278 ml), more frequent tears (23/64), a similar frequency of peritendonitis (22/64) but less frequent pre-Achilles edema (18/64). Sixty-four percent of the Achilles tendon tears were interstitial. Except for two interstitial tears in control patients, the majority of Achilles tears were in symptomatic patients (14/16). Only symptomatic tendons demonstrated partial or complete tendon tears. In addition, calcaneal edema was found almost exclusively in actively symptomatic patients. Thicker tendons were associated more often with chronic symptoms and with tears. When present in symptomatic patients, peritendonitis was usually associated with acute symptoms. The presence of pre-Achilles edema, however, did not distinguish acute from chronic disorders. Conclusion: There is significant overlap of MR findings in symptomatic and asymptomatic Achilles tendons. Furthermore, there is apparently a spectrum of disease in symptomatic tendons ranging from subtle intratendinous and peritendinous signal to partial and complete tendon tear. Received: 17 March 2000 Revision requested: 26 May 2000 Revision received: 19 July 2000 Accepted: 19 July 2000     

Radiological features of 24 periosteal chondrosarcomas

Objective. To report the imaging findings of 24 periosteal chondrosarcomas diagnosed, staged, treated and followed in a single institution, to analyze and define their pattern, and discuss their practical consequences. Design and patients. Plain films, 16 CT examinations and four MRI examinations were reviewed, and compared with the histological evaluation. Results. There were 20 men and four women, aged from 17 to 65 years. Twelve lesions involved the distal femoral metaphyses (8 posteriorly), five the proximal humerus, two the proximal metaphyses of the femur and two of the tibia, two the humeral shafts and one the iliac wing. Size varied from 4 to 11 cm. The cortex was always involved (thick, 15; thin, 13). Typical cartilaginous calcifications and cartilaginous lobules were very frequent. Radial thick periosteal bone formations (n=6) indicated calcifications between the lobules of cartilage. Medullary involvement was rare (n=2). All patients are alive and free of disease. Conclusions. Recognizing periosteal chondrosarcoma is of paramount importance because the prognosis is excellent after adequate local surgery alone. The patterns of other surface tumors of bone are usually different. Received: 31 October 2000 Revision requested: 7 November 2000 Revision received: 5 January 2001 Accepted: 9 January 2001     

Fibrolipomatous hamartoma: pathognomonic on MR imaging

Purpose. To assess the MR imaging characteristics, presenting symptoms, age and nerve distribution of fibrolipomatous hamartoma. Design. A computer search was performed of the term fibrolipomatous hamartoma through the musculoskeletal section MR imaging results at our institution from June 7, 1996 to January 21, 1998 followed by a search of the terms lipomatous hamartoma, median nerve, surrounding fat, increased fatty signal, coaxial, and neuroma. MR images and medical files were retrospectively reviewed by two experienced musculoskeletal radiologists for imaging characteristics, nerve and age distribution as well as for history of trauma. In addition three consultation cases from outside institutions were added for determination of image characteristics. Results. Ten fibrolipomatous hamartomas were identified: eight in the median nerve, one in the ulnar nerve and one in the sciatic nerve. Mean age was 32.3 years (range 4–75 years, SD 21 years). Imaging characteristics were serpiginous low-intensity structures representing thickened nerve fascicles, surrounded by evenly distributed fat, high signal intensity on T1-weighted sequences and low signal intensity on T2-weighted sequences. The amount of fat varied; however, distribution in eight cases (80%) was predominantly between nerve fibers rather than surrounding them peripherally. All had a coaxial-cable-like appearance on axial planes and a spaghetti-like appearance on coronal planes that was not seen in any other type of median nerve abnormality imaged during the study period. Conclusion. The MR imaging characteristics of fibrolipomatous hamartoma are pathognomonic, obviating the need for biopsy for diagnosis. Received: 19 October 1998 Revision requested: 11 December 1998 Revision received: 22 January 1999 Accepted: 25 January 1999     

Radiological diagnosis of abductor denervation after hip surgery

A case of total hip arthroplasty through a direct lateral approach is described. The patient had a markedly positive Trendelenburg test at follow-up. Radiographs showed features consistent with the denervation of the gluteus medius. This was confirmed on CT scan. The standard post-operative radiograph following a total hip replacement may suggest denervation of the gluteus medius. Received: 20 July 2000 Revision requested: 23 August 2000 Revision received: 8 October 2000 Accepted: 10 October 2000     

MR imaging of articular cartilage in the ankle: comparison of available imaging sequences and methods of measurement in cadavers

 Objective. To assess hyaline cartilage of cadaveric ankles using different magnetic resonance (MR) imaging techniques and various methods of measurement. Design and patients. Cartilage thicknesses of the talus and tibia were measured in ten cadaveric ankles by naked eye and by digitized image analysis from MR images of fat-suppressed T1-weighted gradient recalled (FS-SPGR), sequences and pulsed transfer saturation sequences with (FS-STS) and without fat-suppression (STS); these measurements were compared with those derived from direct inspection of cadaveric sections. The accuracy and precision errors were evaluated statistically for each imaging technique as well as measuring method. Contrast-to-noise ratios of cartilage versus joint fluid and marrow were compared for each of the imaging sequences. Results. Statistically, measurements from FS-SPGR images were associated with the smallest estimation error. Precision error of measurements derived from digitized image analysis was found to be smaller than that derived from naked eye measurements. Cartilage thickness measurements in images from STS and FS-STS sequences revealed larger errors in both accuracy and precision. Interobserver variance was larger in naked eye assessment of the cartilage. Contrast-to-noise ratio of cartilage versus joint fluid and marrow was higher with FS-SPGR than with FS-STS or STS sequences. Conclusion. Of the sequences and measurement techniques studied, the FS-SPGR sequence combined with the use of digitized image analysis provides the most accurate method for the assessment of ankle hyaline cartilage.     

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     

Morel-Lavallée effusions in the thigh

 Objective. To assess the radiological features of Morel-Lavallée effusion in the thigh. Design and patients. A restrospective study of clinical records and radiological studies was carried out on three patients with Morel-Lavallée effusion. Results and conclusions. Ultrasound and computed tomography (CT) were able to locate the effusion in the three patients. CT demonstrated a capsule around the lesion. A fluid-fluid level was visible with both techniques. Ultrasound and CT are good methods for assessing patients with Morel-Lavallée effusion of the thigh. CT can be used to distinguish patients requiring surgical treatment from those who could be treated by conservative measures.     

MR imaging of symptomatic osteochondromas with pathological correlation

Objective. To demonstrate the value of MR imaging in the diagnosis and differentiation of the various symptomatic complications of osteochondromas, providing pathological correlation with emphasis on the usefulness of MR imaging as a single imaging modality in these patients. Design. We retrospectively reviewed all MR examinations of clinically symptomatic osteochondromas (30 patients) performed at our institution between March 1990 and October 1997. Patients. Thirty patients had clinically symptomatic osteochondromas during the study period. Twenty patients were male and 10 were female. There were five cases of multiple osteochondromatosis. Pathological correlation was available in 24 patients. Results and conclusion . Symptomatic complications included fracture (7%), osseous deformity limiting range of motion (23%), vascular injury (7%), neurological compromise (10%), bursa formation (27%) and malignant transformation (27%). MR imaging was able to diagnose or suggest the etiology for the clinical symptomatology in all cases, demonstrating that it is an ideal imaging modality in the diagnostic evaluation of symptomatic complications of osteochondromas and often avoids the need for further imaging.     

Spontaneous resolution of a solitary osteochondroma

 Spontaneous regression or resolution of a solitary osteochondroma is infrequent. A case of a surprisingly fast and complete resolution of an osteochondroma of the distal ulna in a 7-year-old boy is presented, with a review of previously reported cases.     

Os sustentaculi: depiction on MR images

 We describe a 14-year old patient with pain in the medial ankle. The MR study depicted a rare accessory ossicle called the os sustentaculi. This accessory bone should not be confused with a fracture of the sustentaculum tali of the calcaneus.     

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     

Unusual longitudinal stress fractures of the femoral diaphysis: report of five cases

We present five cases of a distinctive type of longitudinal stress fracture of the upper femoral shaft in which the fracture line is parallel to the outer surface of the bone, in contrast to the perpendicular orientation to the cortical surface in previously reported cases of diaphyseal stress fractures. In two cases the fracture recurred after 15 and 18 months, respectively. Received: 25 May 1998; Revision requested: 27 July 1998; Revision received: 17 August 1998; Accepted: 8 September 1998     

Imaging of diffuse esophageal leiomyomatosis: two case reports and review of the literature

Diffuse esophageal leiomyomatosis is a rare disorder which may be found in association with leiomyomas in other locations or with other disorders. We report two cases in men, one with associated tracheobronchial involvement, which illustrate the value of imaging in differentiating this entity from other causes of dysphagia and in establishing a diagnosis. Received: 24 December 1998; Revised: 10 May 1999; Accepted: 10 May 1999