Deferoxamine-induced bone dysplasia in patients with thalassemia major

Metaphyseal irregularity and abnormal vertebral bodies resembling a bone dysplasia were seen in two of five children with thalassemia major who were begun on a regimen of hypertransfusion and chelation with deferoxamine before the age of 3 years. Similar changes were not seen in 22 other children in whom chelation was started after the age of 3. Whether the dysplastic bone growth was related to drug dose or age of onset of chelation could not be determined, as deferoxamine dosages differed in the two groups. Findings on radiographs included flattening of the thoracic and lumbar vertebral bodies, circumferential metaphyseal osseous defects, sharp zones of provisional calcification, and widened growth plates. Healing was noted in one of the patients after the dose of deferoxamine was decreased. Zinc levels in both affected patients did not differ from those in the 25 other chelated patients.     

MR imaging findings of acetabular dysplasia in adults

Objective To evaluate the diagnostic accuracy of MR imaging in the identification of labral and articular cartilage lesions in patients with acetabular dysplasia.Design and patients Pre-operative MR imaging was performed on 27 hips in 25 consecutive patients (16 males, 9 females, age range 19–52 years, mean age 31.2 years) with radiographic evidence of acetabular dysplasia (centre-edge angle of Wiberg <20 degrees). The average duration of symptoms was 16.2 months. Two musculoskeletal radiologists assessed MR images in consensus for the presence of abnormality involving the acetabular labrum and adjacent acetabular articular cartilage. A high resolution, non-arthrographic technique was used to assess the labrum and labral chondral transitional zone. Surgical correlation was obtained in all cases by a single surgeon experienced in hip arthroscopy and ten patients with normal hip MRI were included to provide a control group.Results The acetabular labra in the dysplastic hips demonstrated abnormal signal intensity, and had an elongated appearance when compared with the control group (mean length 10.9 mm vs 6.4 mm). Morphological appearances in the labra included surface irregularity, fissures and cleft formation. MR imaging correctly identified the severity of chondral abnormality in 24 of 27 hips (89%) when compared with arthroscopic findings.Conclusions MR imaging demonstrates an elongated labrum, focal intra-substance signal change and irregularity and fissuring of the margins in patients with acetabular dysplasia. Abnormality is also identified at the labral chondral transitional zone, where fissuring, focal clefts, chondral deficiency and subchondral cyst formation may be apparent. A high-resolution, non-arthrographic technique can provide an accurate preoperative assessment and evaluate the presence of premature osteoarthritis.     

Metastatic bone tumor mimicking spontaneous osteonecrosis of the medial condyle of the femur: misleading appearance on MR imaging

We report a case of a metastatic bone tumor that mimicked spontaneous osteonecrosis of the medial condyle of the femur on magnetic resonance imaging. Received: 5 October 1999 Revision requested: 11 November 1999 Revision received: 10 January 2000 Accepted: 17 January 2000     

Red and yellow marrow in the femur: age-related changes in appearance at MR imaging

T1-weighted magnetic resonance (MR) images of the femur in 77 subjects, aged 1 month to 24 years, were retrospectively analyzed for the distribution and appearance of red and yellow marrow. The subjects were divided into six age groups, and the signal intensity and degree of mottling of marrow in the proximal epiphysis, proximal metaphysis, diaphysis, distal metaphysis, and distal epiphysis were observed and assigned a grade. Bone marrow with low or intermediate to slightly increased signal intensity was considered red marrow, while bone marrow with increased signal intensity was considered fatty marrow. An orderly progression of red to yellow marrow conversion in the femur was appreciated first in the diaphysis (ages 1-10 years) and then in the distal metaphysis (ages 10-20 years), with an adult pattern seen by age 24 years. The MR spectrum of red and yellow marrow differs from the existing macroscopic anatomical data because MR imaging is apparently more sensitive to the presence of microscopic fat in bone marrow.     

Hip pain in adults: MR imaging appearance of common causes

To determine the exact origin of hip pain can be challenging. Symptoms apparently originating from the hip may arise from the pelvis, the sacroiliac joint, the lumbar spine, periarticular structures such as muscles and bursae, or from unexpected sites such as the abdominal wall, the genitourinary tract, or the retroperitoneal space. This article reviews the differential diagnosis of hip pain arising from the hip and surrounding structures and the role of different imaging methods with emphasis on magnetic resonance imaging where most recent advances have occurred.     

Posterior distal femoral and proximal tibial metaphyseal stripes at MR imaging in children and young adults

PURPOSE: To determine the frequency and distribution of the hyperintense stripe seen along the posterior surface of distal femoral and proximal tibial metaphyses at magnetic resonance (MR) imaging. MATERIALS AND METHODS: One hundred forty-two MR imaging studies obtained in 139 children and young adults were reviewed. The authors recorded the presence and distribution of posterior distal femoral and proximal tibial metaphyseal stripes. Presence of stripe was correlated with patient age and sex and with patency of the adjacent physis. Fifty-nine studies of adults were reviewed similarly. Two-way analysis of variance was performed to compare mean patient age for sex among four different categories that were based on stripe presence and physeal patency. Orthogonal contrasts were used to determine whether a linear trend across the categories existed. In one cadaveric femur, imaging and histologic analysis were performed. RESULTS: A metaphyseal stripe was seen in all patients with a completely or partially open physis (110 femora, 102 tibiae) and in 56 femora and 60 tibiae in the patients with fused physes. Thirty-five femora and 35 tibiae showed no stripe; all patients were skeletally mature. Correlations between metaphyseal stripe visualization and physeal patency were significant (P <.001). Differences in mean patient age among the four categories were significant for both (femoral and tibial) locations (P <.001), and a linear trend with age (P <.001) was demonstrated. This linear trend was also observed in both sexes (P <.001). Histologic analysis revealed highly vascular loose fibrous tissue. CONCLUSION: A posterior metaphyseal stripe is seen at MR imaging of the skeletally immature knee and likely reflects normal bone growth.     

Bladder paraganglioma in adults: MR appearance in four patients

Purpose

To document the magnetic resonance imaging (MRI) characteristics of paraganglioma of the urinary bladder in adults.

Materials and methods

The MRI findings and clinical features of pathologically-proven bladder paraganglioma in four patients (three men, one woman; age range, 39–62 years; mean age, 46.8 years) were reviewed retrospectively. All patients underwent MRI in a 1.5 T instrument. The MRI features of the lesions were analyzed, with emphasis on the size, shape, location, margin, signal intensity, degree of MRI enhancement, and apparent diffusion coefficient (ADC) values.

Results

The bladder paragangliomas were located in the posterior vesicle wall (n = 2), in the dome of the bladder wall (n = 1), or the inferoanterior wall (n = 1). On MR images, the tumors were round (n = 1) or oval-shaped (n = 3) and all exhibited well-circumscribed margins and broad-based attachment to the bladder wall. On T1-weighted images, the lesions demonstrated homogeneous hyperintensity (n = 4) compared to the gluteus maximus muscle; while on T2-weighted images, they showed slight hyperintensity (n = 4). On contrast-enhanced MR images, all lesions showed intense enhancement. On diffusion-weighted imaging (DWI), the lesions showed hyperintensity (n = 4) and the mean ADC value was 0.973 × 10⁻³ mm²/s.

Conclusion

Bladder pheochromocytoma appears as a round or oval-shaped intensely enhancing lesion with T1 hyperintensity; these characteristics may facilitate the preoperative determination.     

Brodie Abscess: MR imaging appearance in 10 patients

The magnetic resonance (MR) imaging features of Brodie abscess have not yet been fully evaluated. Ten patients with Brodie abscess, eight of long bone and two of vertebra, were studied with MR imaging. Long bone abscess had a characteristic “target” appearance with four layers: (a) a center with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR (short-inversion-time inversion recovery) images, (b) an inner ring isointense to muscle on T1-weighted images and with high signal intensity on T2-weighted and STIR images, (c) an outer ring hypoin-tense on all images, and (d) a peripheral halo hypointense on T1-weighted images. In six of eight cases, a soft-tissue mass was found. The two vertebral abscesses had a less specific appearance, with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR images. Only the peripheral halo was clearly identified in both cases.     

Meniscal ossicle: MR imaging appearance in three patients

Meniscal ossicles are rare. Radiographically, these ossicles often are mistaken for intra-articular bodies. We evaluated the application of magnetic resonance imaging to determine whether this technique is efficacious in differentiating meniscal ossicles from intra-articular bodies.     

MR imaging of diffuse bone marrow replacement in pediatric patients with cancer

In the magnetic resonance (MR) imaging examinations of three children with tumors (two neuroblastoma, one rhabdomyosarcoma) and three with leukemia, the marrow demonstrated a diffuse, uniform pattern of hypointensity on T1-weighted images and hyperintensity on T2-weighted images. The authors observed that this reversal ("flip-flop") of the usual MR characteristics of fatty marrow was seen in the epiphyses, metaphyses, and diaphyses. The purpose of this study was to establish the radiographic and clinicopathologic correlates of this MR finding on the basis of findings from plain radiographs, bone scans, and bone marrow aspirates. Plain radiographs and bone scans demonstrated either normal findings or changes limited to the metaphyses. In all patients, analysis of bone marrow aspirates demonstrated metastases. The authors concluded that even in the absence of evidence of discrete bone metastases on a plain radiograph or a bone scan, this diffuse and uniform "flip-flop" pattern reflects diffuse marrow replacement by tumor cells.     

Brain MR imaging abnormalities in pediatric patients after allogeneic bone marrow transplantation

Objective

Our aim was to analyze brain MRI findings in pediatric patients who developed neurologic complications after allogeneic bone marrow transplantation.

Materials and methods

This prospective study included 33 consecutive patients (age range from 3 to 18 years, mean 11.8 ± 5.1 years). They were referred to the MRI unit because of the neurological symptoms in the post transplant period. The underlying disorders included: non malignant hematological disorders (n = 20, 60.6%) and hematological malignancies (n = 13, 39.4%). Onset of the presentation of the complication in relation to the chronology of the transplant was identified in each patient (phase1: from days 0 to 30, phase 2: from days 30 to 100, and late phase after day 100).

Results

According to the MRI findings 6 patients (18.2%) showed normal examinations. Twenty-seven patients (81.8%) with positive MRI findings, are grouped into 7 main categories: posterior reversible encephalopathy syndrome (n = 16, 48.48%), intracranial hemorrhage (n = 2, 6.06%), cerebral venous sinus thrombosis (n = 1, 3.03%), CNS infection (n = 2, 6.06%), leukoencephalopathy (n = 5, 15.15%), mild atrophy (n = 11, 33.33%), CNS relapse (n = 1, 3.03%), with 9 patients having more than one diagnosis. Ten cases of PRES and 1 case of sinus thrombosis were detected in phase 1. Two cases of PRES and 2 cases of intracranial hemorrhage were detected in phase 2. Four cases of leukoencephalopathy, 4 cases of PRES, 2 cases of CNS infection, and 1 case of CNS relapse were detected in phase 3.

Conclusion

CNS complications after allogenic BMT in pediatric patients could cause a significant clinical problem. MRI can provide early diagnosis and follow-up to monitor treatment changes. Knowing the onset of the presentation of the complication in relation to the chronology of the transplant is important as it provides significant guidance on which causes to consider.     

MR imaging based strategies in limb salvage surgery for osteosarcoma of the distal femur

Objective. To analyse to what extent MR imaging based decisions were correct in determining the surgical procedure in patients with osteosarcoma of the distal femur. Design. We compared the findings on MR imaging that determined the surgical strategy with the actual surgical findings or histopathological specimen. We assessed to what extent MR images could be used to determine the surgical procedure in patients with osteosarcoma. Patients. Between 1985 and 1992, 34 patients with an osteosarcoma were treated. Two patients had a low-grade osteosarcoma. Thirty-two patients with a high-grade osteosarcoma of the distal femur (17 stage IIB, 15 stage III) were included in this study. Surgical options consisted of either limb salvage surgery or ablative surgery, which included the Van Nes-Borggreve rotationplasty. Limb salvage surgery consisted of extra-articular or transarticular resection, followed by reconstruction. Surgery was planned depending on the local extent of the tumour as depicted on the MR studies, coupled with data from the biopsy, age, patient compliance and histological grade. Follow-up was available in all patients. Nine of 17 patients graded as IIB were alive with an average follow-up of 68 months (range 46–109 months), of whom one has metastases. No local recurrence was encountered. Results. If no tumour involvement on MR imaging was found and this was used as a determining factor, this proved to be correct at subsequent analysis. We found that in eight of 11 cases, when MR images suggested a close relationship between tumour and nerve, an oncologically safe plane could be achieved during surgery. In three, a free plane could not be accomplished, as confirmed at histopathological examination. Hence, when nerve involvement was equivocal on MR imaging we found it valuable to reassess nerve involvement during surgery and reconsider limb salvage surgery. When the decisive factor was the vascular involvement and tumour extension was read as equivocal, it was possible to obtain a oncologically safe plane in six of 13 cases. When comprehensive tumour involvement of any structure was noted pre-operatively, it proved to be correct at histopathological examination, except for one case of assumed vascular involvement that proved to be free. Conclusions. If no tumour involvement of a structure was found on MR imaging and this was used as a determining factor, this proved to be correct. When nerve involvement was equivocal on MR imaging we found it valuable to reassess nerve involvement during surgery and reconsider limb salvage surgery. Extensive tumour involvement of any structure, as shown by MR imaging, could be used correctly as a decisive argument in planning a surgical procedure.     

MR imaging of bone marrow in glycogen storage disease type IB in children and young adults.

OBJECTIVE: Patients with glycogen storage disease type IB have neutropenia and neutrophil dysfunction that predispose them to frequent infections, for which they are given granulocyte colony--stimulating factor. Because neutropenia is a consequence of defects in myeloid maturation, the bone marrow aspirations show hypercellularity due to myeloid hyperplasia. This study evaluated MR imaging of bone marrow in glycogen storage disease type IB with and without granulocyte colony-stimulating factor. CONCLUSION: As confirmed by the histologic results in bone marrow aspirations, abnormal findings on MR images of bone marrow in patients with glycogen storage disease type IB indicate an increased myelopoietic activity, which is augmented by treatment with granulocyte colony-stimulating factor.     

Congenital pseudarthrosis of the tibia in pediatric patients: MR imaging

OBJECTIVE: The purpose of this study was to describe the characteristics of congenital pseudarthrosis of the tibia on MR images of infants and children and to assess the value of MR imaging in evaluating this disease. CONCLUSION: MR imaging of congenital pseudarthrosis allows assessment of the type and extension of the disease. It is especially recommended for the evaluation of periosteal and soft-tissue changes near the pseudarthrosis.     

Normal spinal bone marrow in adults: dynamic gadolinium-enhanced MR imaging

PURPOSE: To determine the patterns of dynamic enhancement of normal spinal bone marrow in adults at gadolinium-enhanced magnetic resonance (MR) imaging and the changes that occur with aging. MATERIALS AND METHODS: Dynamic contrast material-enhanced MR imaging of the thoracolumbar spine was performed in 71 patients. The maximum percentage of enhancement (Emax), enhancement slope, and enhancement washout were determined from bone marrow enhancement time curves (ETCs). The bone marrow signal intensity on T1-weighted spin-echo MR images was qualitatively classified into three grade categories. Quantitative ETC values were correlated with patient age and bone marrow fat content grade. Statistical analysis included mean t test comparison, analysis of variance, and regression analysis of the correlations between age and quantitative MR parameters. RESULTS: Emax, slope, and washout varied widely among the patients. Emax values were obtained within 1 minute after contrast material injection and ranged from 0% to 430%. Emax values were significantly higher in patients younger than 40 years than in those aged 40 years or older (P <.001). These values decreased with increasing age in a logarithmic relationship (r = 0.71). Emax values decreased as fat content increased, but some overlap among the fat content grades was noted. Analysis of variance revealed that Emax was significantly related to age (younger than 40 years vs 40 years or older) (P <.001) and fat content grade (P <.001) but not significantly related to sex. CONCLUSION: Dynamic contrast-enhanced MR imaging patterns of normal spinal bone marrow are dependent mainly on patient age and fat content.     

Endometriosis: appearance and detection at MR imaging

Thirty-nine magnetic resonance (MR) studies were performed on 31 women with surgically proved endometriosis. A total of 88 endometriotic lesions ranging in size from 0.2 to 7.5 cm were detected on 24 of 30 MR images of women. The signal intensities ranged from hyperintense on all pulse sequences (41 of 88) to hypointense on all sequences (24 of 88); the remainder demonstrated signal intensities corresponding to the appearances of acute, subacute, and chronic hematomas. Hypointense or signal-void rims on both T1- and T2-weighted images were detected in 35 lesions. Identification of the disease with MR imaging versus concurrent surgery was compared for 76 sites in 19 patients. Findings were true-positive in 24 cases, false-negative in ten, true-negative in 32, and false-positive in seven, resulting in an MR sensitivity of 71% and specificity of 82%. Adhesions obscured the disease at laparoscopy in three patients. MR imaging cannot be used as a substitute for laparoscopy in the definitive diagnosis or staging of endometriosis. However, it can be used to monitor treatment response in place of laparoscopy once a diagnosis is firmly established.     

Mechanisms of osteoarthritis in the knee: MR imaging appearance

Osteoarthritis has grown to become a widely prevalent disease that has major implications in both individual and public health. Although originally considered to be a degenerative disease driven by “wear and tear” of the articular cartilage, recent evidence has led to a consensus that osteoarthritis pathophysiology should be perceived in the context of the entire joint and multiple tissues. MRI is becoming an increasingly more important modality for imaging osteoarthritis, due to its excellent soft tissue contrast and ability to acquire morphological and biochemical data. This review will describe the pathophysiology of osteoarthritis as it is associated with various tissue types, highlight several promising MR imaging techniques for osteoarthritis and illustrate the expected appearance of osteoarthritis with each technique. J. Magn. Reson. Imaging 2014;39:1346–1356 . © 2014 Wiley Periodicals, Inc .     

Membranous lipodystrophy: MR imaging appearance of the brain

Five patients with membranous lipodystrophy (lipomembranous polycystic osteodysplasia with progressive dementia) underwent magnetic resonance (MR) imaging of the brain. T2-weighted MR images showed atrophied cerebral white matter with dilated ventricles; increased signal intensity of the white matter; and decreased signal intensity of the thalamus, putamen, caudate nucleus, and cerebral cortex. Although each single finding is not specific, the combination of the above MR findings when coupled with skeletal lesions strongly suggests this rare disease.