Imaging of arteriovenous malformation following stereotactic radiosurgery

Background. Stereotactic radiosurgery allows for a high dose of focused radiation to be delivered to a small lesion such as an arteriovenous malformation (AVM). The clinical change and brain response over time to this localized high-dose radiation can be quite striking. Objective. The objective of this study to describe and analyse the imaging changes following radiotherapy for AVMs. Materials and methods. The clinical presentation and the imaging changes following radiotherapy in two patients were studied over the course of 1–2 years. Results. The imaging findings include diffuse low attenuation and contrast enhancement on CT. High-signal lesions were apparent on T2-weighted MR images with prominent contrast enhancement on T1-weighted images. Ring enhancement occurred over time. While new changes appeared over 12 months, these changes diminished during the second year. Conclusion. Radiotherapy induces inflammatory changes that are generally reversible but can lead to parenchymal destruction. These imaging changes are often nonspecific and therefore must be interpreted in light of clinical symptomatology and the time course since treatment. These patients should receive routine MR imaging within 3 months after radiosurgery with follow-up imaging at 6, 12, and 18 months. Received: 13 February 1996 Accepted: 29 June 1996     

Dynamic gadolinium-enhanced subtraction MR imaging – a simple technique for the early diagnosis of Legg-Calvé-Perthes disease: preliminary results

Purpose. To determine whether the simple technique of dynamic gadolinium-enhanced subtraction MR imaging, which is available on standard MR units, can detect ischemia of the femoral head in children with early Legg-Calvé-Perthes disease (LCP). Materials and methods. Bone perfusion of eight hips in four patients (mean age 7.5 years) was studied using dynamic gadolinium-enhanced subtraction MR imaging at the onset of proven LCP (with initial negative plain films). Enhancement of subtracted images was compared with that on standard MR images and with bone scintigraphy find- ings. Results. Subtraction MR imaging depicted ischemia as a widespread absence of enhancement and was in good agreement with bone scintigraphy. The subtraction technique improved the sensitivity and the specificity of MR imaging in two children. Furthermore, subtraction MR imaging allowed recognition of the pattern of early reperfusion. Conclusion. Our preliminary results indicate that dynamic gadolinium-enhanced subtraction MRI is a simple and promising means of early recognition of ischemia in LCP. Received: 12 April 1996 Accepted: 25 September 1996     

Magnetic resonance imaging of renal osteodystrophy in children

Background. Improved life expectancy of children with chronic renal failure (CRF) has increased the number of patients with renal osteodystrophy and has brought to light novel and severe forms of the disease. These factors have contributed to the need to evaluate new, noninvasive imaging modalities for the detection of bone involvement. Objectives. To evaluate the potential of MRI in the detection of the bone changes of renal osteodystrophy as compared to conventional X-rays. Materials and methods. Fourteen children with CRF were examined with a 0.5-T MR unit using TI-weighted and STIR sequences and conventional radiographs. The following features were reviewed in a nonblinded study: skeletal deformities, thickening of cortical bone, trabecular pattern, intraosseous soft-tissue masses, osteonecrosis, extraskeletal calcifications and bone marrow signal changes. Results. MRI adequately demonstrated skeletal deformities, cortical thickening and irregular trabecular pattern. It showed osteonecrosis and intraosseous soft-tissue masses more conspicuously than X-ray. In addition, it revealed diffuse nonspecific signal changes in the bone marrow. Conclusion. MRI is a potentially useful tool for evaluating the bone changes of renal osteodystrophy. Received: 28 February 1997 Accepted: 23 June 1997     

MR imaging in congenital lower limb deformities

Treatment for children with congenital deformities of the lower extremities may vary, depending on the state of the unossified skeletal structures and surrounding soft tissues. The purpose of our study was to demonstrate the spectrum of the osteochondral and extrasosseous abnormalities as depicted with MR imaging. We retrospectively reviewed MR examinations of 13 limbs of ten children (aged 1 month-9 years, mean 2.1 years) with longitudinal and transverse deformities of the lower extremities. The lesions imaged were fibular hemimelia (n = 5), tibial hemimelia (n = 5), and congenital constriction bands (n = 3). Each examination was assessed for abnormalities in the osteocartilaginous and extraosseous (articular or periarticular components such as ligaments, tendons, and menisci; the muscles and the arteries) structures. Abnormalities were seen in all patients. Osteocartilaginous abnormalities in the patients with longitudinal deformities included abnormal distal femoral epiphyses, abnormal proximal tibial physes, hypertrophied and dislocated proximal fibular epiphyses, unsuspected fibular and tibial remnants, and absence or coalition of the tarsal bones. No osteocartilaginous abnormalities were seen in the patients with congenital constriction bands. Articular abnormalities about the knee in patients with either form of hemimelia included absent cruciate ligaments and menisci, dislocated or absent cartilaginous patellae, absent patellar tendons, and abnormal collateral ligaments. All but one limb imaged had absent or attenuated muscle groups. Of the nine MR arteriograms performed at the level of the knee, eight were abnormal. The normal popliteal trifurcation was absent or in an abnormal location. We conclude that MR imaging of children with congenital lower extremity deformities shows many osteochondral and extraosseous abnormalities that are not depicted by conventional radiography. This information can help to plan early surgical intervention and prosthetic rehabilitation.Presented at the 1994 annual meeting of The Society for Pediatric Radiology.     

Pilomatricomas in children: imaging characteristics with pathologic correlation

Background Although pilomatricoma commonly occurs in children, there is still a poor understanding of the imaging characteristics of pilomatricoma and lack of agreement regarding its imaging findings and histopathologic features. Objectives To characterize the radiologic appearance of pilomatricomas on US, CT, and MR and to correlate the imaging findings with histopathologic features. Materials and methods The imaging findings of 47 pilomatricomas on US (n = 17), CT (n = 31), and MR (n = 5) were retrospectively evaluated. Pathologic specimens of all cases were reviewed and compared with imaging findings. Results All lesions were well-circumscribed, subcutaneous nodules with partial attachment to the overlying skin. On US, the lesions were mostly hyperechoic with posterior acoustic shadowing and hypoechoic rim. On CT, they appeared as enhancing soft-tissue masses with varying amounts of calcification. MR findings were internal reticulations and patchy areas on T2-weighted images and contrast-enhanced T1-weighted images, corresponding to edematous stroma on pathology. Peritumoral inflammatory changes and connective capsule on pathology were well correlated with imaging findings. Conclusion Pilomatricoma should be considered when US or CT shows a well-defined hyperechoic or calcific nodule in subcutaneous fat attached to the skin in children. MR images may be helpful in diagnosis. Pathologic findings are well correlated with imaging findings.     

Gadolinium-enhanced MR imaging demonstrates abduction-caused hip ischemia and its reversal in piglets

Purpose To determine whether gadoliniumenhanced MR imaging can detect early reversible ischemia of the capital femoral epiphysis and physis induced by hip hyperabduction in piglets.Materials and methods Thirteen 1-to 3-week-old piglets were placed in maximal abduction of both hips and studied with dynamic gadolinium-enhanced MR imaging 1–6 h later to assess ischemia of the 26 femoral heads. They were then allowed to ambulate freely for 1 or 7 days, and reimaged in neutral position to assess reperfusion. Enhancement was evaluated on MR images and compared with histologic findings.Results Ischemia after hyperabduction developed in all 26 cartilaginous epiphyses and in 85% of the physes. The most frequent abnormality was a sharply marginated nonenhancing area in the anterior part of the femoral head. A smaller area of ischemia developed in the posterior part of the femoral head, adjacent to the acetabular rim. The secondary center of ossification was ischemic in 56% of the hips after 1 h of abduction and in all hips after 4 or 6 h (p=0.02). The overall severity of ischemia was greater with increasing abduction time (p<0.001) and increasing degree of abduction (p<0.01). There was partial reperfusion in 83% of the hips after 1 day of ambulation and complete reperfusion in all 26 hips (100%) after 1 week.Conclusion Enhanced MRI detects early ischemia of the epiphyseal and physeal cartilage and the epiphyseal marrow. In piglets, ischemia due to hyperabduction is reversible if corrected within 6 h.Editor's note The publication by Dr. Jaramíllo et al.Gadolinium-enhanced MR imaging demonstrates abduction-caused hip ischemia and its reversal in piglets, represents the 1995 Caffey Award winning paper at The Society for Pediatric Radiólogy annual meeting. This paper will be published in bothPediatric Radiology and theAmerican Journal of Roentgenology in recognition of its award winning excellence. This joint publication is an honor andnot a double publication. From now on, each year's Caffey Award winning paper will be so honored in both journals.     

MRI diagnosis of suspected atlanto-occipital dissociation in childhood

Objective. To demonstrate the utility of magnetic resonance (MR) imaging in the diagnosis of complete and partial ligamentous injuries in patients with suspected atlanto-occipital dissociation (AOD). Materials and methods. Five patients with suspected AOD had MR imaging performed within an average of 4 days after injury. MR scans were reviewed with specific analysis of craniocervical ligamentous structures. Charts were reviewed to obtain clinical information regarding presentation, treatment, hospital course, and outcome. Results. Two patients demonstrated MR evidence of complete AOD. One had disruption of all visualized major ligamentous structures at the craniocervical junction with anterolisthesis and evidence of cord damage. The second had injuries to the tectorial membrane, superior band of the cruciform ligament, apical ligament, and interspinous ligament at C 1–2. The remaining three patients sustained incomplete severance of the ligamentous structures at the craniocervical junction. All patients demonstrated subtle radiographic findings suggestive of AOD, including soft tissue swelling at the craniocervical junction without fracture. The two patients with complete AOD died. The three patients with partial AOD were treated with stabilization. On follow-up, these three children were asymptomatic following their craniocervical injury. Conclusion. MR imaging of acute AOD provides accurate identification of the craniocervical ligaments injured, classification of full versus partial ligamentous disruption, and analysis of accompanying spinal cord injury. This information is important for early appropriate neurosurgical management and preservation of neurologic function in survivors. Received: 11 February 1998 Accepted: 20 November 1998     

Radiological evaluation of pulmonary vein obstruction including two examinations by magnetic resonance imaging

Congenital obstruction of the pulmonary vein without anomalous drainage can cause long-standing pulmonary congestion and pulmonary arterial hypertension, and it may include stenosis of individual pulmonary veins and pulmonary vein atresia. We reviewed seven cases of pulmonary vein obstruction, five of which were accompanied by other cardiac anomalies. Right pulmonary veins were involved in all seven cases; one case was bilateral. Pulmonary veins were occluded totally in five and partially in three lungs. Diagnostic pulmonary catheterization and angiography were performed. Chest radiographs of total occlusion cases showed decreased lung volume, features of pulmonary edema, interstitial lesions, and pleural changes, which were quite specific, whereas pulmonary venous dilatation was the dominant finding in partial obstruction cases. Pulmonary perfusion scan (n=3) showed total perfusion defects in the cases with total occlusion of pulmonary veins. Magnetic resonance (MR) imaging (n=2) demonstrated totally occluded pulmonary veins at the venoatrial junction in two lungs and membranous focal obstruction in one lung. Two children underwent pneumonectomy and had the diagnosis histologically confirmed. Although catheterization and angiography are essential for the diagnosis of pulmonary vein obstruction, MR imaging is a useful adjunct.     

MR imaging of simple bone cysts in children: not so simple

Objective. The unicameral bone cyst (UBC) is a common cystic bone lesion seen in children. We review and summarize its MR findings, focusing on their appearance following contrast enhancement, and correlating them to known histologic features of UBC. Subjects and methods. A retrospective review of 20 cases (13 boys, 7 girls; age range, 1–17 years; mean age, 8.9) diagnosed as UBC was conducted. Clinical histories, radiographic and MR features, follow-up data, and available pathologic findings were noted. Results. At initial presentation 18 (90 %) of the patients with UBC had a history of acute or remote pathologic fracture. Cysts with history of fracture displayed heterogeneous fluid signals on T1- (n = 9, 50 %), and T2-weighted (n = 15, 83 %) MR images. Gadolinium-enhanced images were obtained in 15 of the 18 UBC cases with history of previous fracture. All showed enhancement with focal, thick peripheral, heterogeneous, or subcortical patterns. Focal nodules of homogeneous enhancement (diameter > 1 cm) within the UBC (n = 5) correlated with areas of ground-glass opacification on plain film. Other interesting MR features were fluid-fluid levels (n = 11), “fallen-leaf” sign (n = 1), soft-tissue changes (n = 2), and detection of septations not seen on plain film (n = 2). Conclusion. UBCs frequently appear complicated on MR imaging, with heterogeneous fluid signals and regions of nodular and thick peripheral enhancement related to previous pathologic fracture and early healing. Received: 27 December 1999 Accepted: 6 March 2000     

US, CT and MR imaging characteristics of nephroblastomatosis

Objectives. To describe the imaging features of nephroblastomatosis with US, CT and MR, to point out characteristics of differentiation between nephrogenic rests (NR) and Wilms' tumour (WT) and to determine the most appropriate imaging modality. Materials and methods. We reviewed the US, CT and MR images of 29 cases of histopathologically confirmed nephroblastomatosis sent to our department for reference evaluation (German nephroblastoma study). The series included 17 kidneys with NR, 6 kidneys with WT and 32 kidneys with both NR and WT. Results. NR presented as multinodular, peripheral, cortical lesions, the diffuse form of distribution being less common. Foci were homogeneous and of low echogenicity, density or signal intensity. The lesions were most clearly depicted with contrast-enhanced CT and T1-weighted (T1-W) MR images. Lesions smaller than 1 cm were rarely identified by US. The most reliable criterion to differentiate NR from WT was their homogeneity. Conclusions. Contrast-enhanced CT and T1-W MR images are of similar potential and superior to US in the diagnosis of nephroblastomatosis. Due to the significant radiation dose of serial CT, MR imaging should be the method of choice wherever it is available. The cost-effectiveness and availability of US makes it ideal for serial follow-up of known lesions. Received: 6 June 1997 Accepted: 9 January 1998     

Role of MRI in the management of children with diffuse pontine tumors: a study of 15 patients and review of the literature

Background: Pontine tumors carry the worst prognosis of all brain tumors. In most cases, the diagnosis is based solely on MR imaging, without biopsy. Objective: To describe the MR findings of pontine tumors at diagnosis and during follow-up and correlate those with prognosis and to assess the value of MR imaging in patient management compared to clinical evaluation. Materials and methods: Ninety-one MR scans of 15 children with diffuse pontine tumors were reviewed at diagnosis and during follow-up. The parameters analyzed were as follows: tumor extent, area, and volume; encasement of the basilar artery; presence of exophytic component; necrosis; cysts; hydrocephalus; and intensity and enhancement. Findings were correlated to length of progression-free and overall survival. Trends of amelioration or worsening on imaging were compared with the clinical findings. Results: Median length of progression-free survival was 10 months, and median survival was 20 months. Only hydrocephalus at presentation was associated with shorter progression-free survival (P=0.02). On the last examination of each patient, the craniocaudal diameter was significantly greater than at diagnosis (P=0.03). The concordance between the imaging and the clinical findings was good.Conclusion: MR is the mainstay for the diagnosis and management of pontine tumors. Cranial growth seems to be an ominous sign. However, the prognostic value of MR is limited. MR findings correlate well with the clinical examination.     

Tumor volume or dynamic contrast-enhanced MRI for prediction of clinical outcome of Ewing sarcoma family of tumors

Background. The identification of risk factors that predict poor clinical outcome at the time of diagnosis could lead to intensified early therapy and improved outcome for pediatric patients with Ewing sarcoma family of tumors (ESFT). Objective. To compare the effectiveness of static magnetic resonance (MR) imaging measurements of tumor volume with variables obtained by dynamic contrast-enhanced MR imaging (DEMRI) in predicting ESFT outcome. Methods. MR examinations that included DEMRI were retrospectively reviewed. The analyses included 45 examinations of 21 patients with ESFT (performed from 1992 to 1996). Tumor volumes were measured on the static MR images, and the regions of interest were selected for DEMRI analysis. The relationships of static MR imaging and DEMRI variables with the probability of progression-free survival (PFS) and disease-free survival (DFS) were determined. Results. Larger tumor volume at the time of diagnosis predicted poorer PFS and DFS estimates. No DEMRI variable predicted outcome. Conclusion. Determination of tumor volume by static MR imaging at the time of diagnosis is a simple and reliable method of predicting the clinical outcome of patients with ESFT. DEMRI is not as reliable a technique as static MR imaging for predicting the outcome of these patients. Received: 8 September 2000 Accepted: 28 Feburary 2001     

MR findings of complicated multifetal gestations

This paper presents a review of various complications of multifetal gestations identified on MR imaging and highlights findings of those complications unique to monochorionic twinning. The goal is to illustrate the potential of MR as a useful application in these clinical circumstances. A total of 32 women with multifetal gestations and suspected complication detected initially by US underwent T2-weighted MR imaging. Additional T1-weighted images were obtained when intracranial hemorrhage was suspected. MR and US findings were compared in all cases. Of 32 cases, six demonstrated fetal complications specific to monochorionic twinning; the findings consisted of conjoined twins (n=2), twin-twin transfusion syndrome (n=1), co-twin demise with embolic disease (n=2), and twin-reversed arterial perfusion. (TRAP) syndrome (n=1). MR imaging confirmed US findings in all cases and was particularly helpful in delineating the extent of intracranial complications of monochorionic twins. The technique also showed improved anatomical detail in cases of conjoined twins. MR imaging provided additional information in cases of complicated monochorionic twinning, making it a useful complementary technique when combined with initial sonographic assessment.     

Cervical neurofibromas in children with NF-1

Background. Children with neurofibromatosis type 1 (NF1) are at increased risk of developing plexiform neurofibroma throughout the body, including the cervical soft tissues. However, the incidence of cervical soft tissue tumors and the value of screening MR for children with NF1 are not known. Purpose. The purposes of this study were to determine the incidence and clinical significance of cervical tumors seen on MR imaging in children with NF1. Materials and methods. A retrospective review of the brain and orbit MR with cervical images obtained on 95 children who meet the NIH consensus criteria for NF1 and who are followed at our neurofibromatosis clinic was carried out. Results. Cervical tumors were found on MR imaging in 21 of 95 (22 %) children. Of 21 children with cervical tumors, 14 children were determined to be surgical candidates. In nine children, MR imaging altered the clinical management by demonstrating tumors for which surgery was indicated, but the tumors were not suspected prior to MR imaging. Conclusion. Cervical tumors are commonly seen in children with NF1. MR imaging may demonstrate a significant number of tumors that require surgery, but were not suspected prior to MR imaging. Received: 1 July 1998 Accepted: 14 October 1998     

Vitamin D deficiency causes rickets in an urban informal settlement in Kenya and is associated with malnutrition

The commonest cause of rickets worldwide is vitamin D deficiency, but studies from sub‐Saharan Africa describe an endemic vitamin D‐independent form that responds to dietary calcium enrichment. The extent to which calcium‐deficiency rickets is the dominant form across sub‐Saharan Africa and in other low‐latitude areas is unknown. We aimed to characterise the clinical and biochemical features of young children with rickets in a densely populated urban informal settlement in Kenya. Because malnutrition may mask the clinical features of rickets, we also looked for biochemical indices of risk in children with varying degrees of acute malnutrition. Twenty one children with rickets, aged 3 to 24 months, were identified on the basis of clinical and radiologic features, along with 22 community controls, and 41 children with either severe or moderate acute malnutrition. Most children with rickets had wrist widening (100%) and rachitic rosary (90%), as opposed to lower limb features (19%). Developmental delay (52%), acute malnutrition (71%), and stunting (62%) were common. Compared to controls, there were no differences in calcium intake, but most (71%) had serum 25‐hydroxyvitamin D levels below 30 nmol/L. These results suggest that rickets in young children in urban Kenya is usually driven by vitamin D deficiency, and vitamin D supplementation is likely to be required for full recovery. Wasting was associated with lower calcium (p = .001), phosphate (p < .001), 25‐hydroxyvitamin D (p = .049), and 1,25‐dihydroxyvitamin D (p = 0.022) levels, the clinical significance of which remain unclear.     

Proton MR spectroscopy in three children with Tay-Sachs disease

Background: Tay-Sachs disease is an inherited metabolic disease caused by the accumulation of GM₂ gangliosides in the central nervous system. Deficiency of hexosaminidase A leads to the accumulation of gangliosides in neurons, axons and glial cells. Objective: To present the cranial MRI and proton MR spectroscopy findings of children of Tay-Sachs disease. Materials and methods: Three children aged 10, 20 and 21 months were examined. Results: On T2-weighted MR images there were hyperintense signal changes in the basal ganglia and cerebral white matter. MR spectroscopy demonstrated an increase in myoinositol/creatine and choline/creatine ratios with a decrease in the N-acetyl aspartate/creatine ratio. Conclusions: The spectroscopy findings support demyelination, gliosis and neuronal loss in the neuropathological process of Tay-Sachs disease.     

MR imaging of glioblastoma in children: usefulness of diffusion/perfusion-weighted MRI and MR spectroscopy

Background Glioblastoma is relatively uncommon in childhood and maybe difficult to differentiate from other brain tumors such as primitive neuroectodermal tumor, ependymoma, or benign astrocytoma. Objective To describe the characteristic MR features in children with glioblastoma and to evaluate the usefulness of diffusion and perfusion MR imaging and MR spectroscopy in pediatric glioblastoma. Materials and methods MR imaging in 11 children (12 tumors) with biopsy-proven glioblastoma was reviewed retrospectively. In one patient, there was a recurrent glioblastoma. We reviewed CT and MRI imaging for tumor location, density/signal intensity, and enhancement pattern. Routine MR imaging was performed with a 1.5-T scanner. In six patients, diffusion-weighted MR images (DWIs) were obtained with a single-shot spin echo EPI technique with two gradient steps, and apparent diffusion coefficients (ADCs) were calculated. Using the gradient EPI technique, perfusion-weighted MR images (PWIs) were obtained in four patients from the data of dynamic MR images. The maximum relative cerebral blood volume (rCBV) ratio was calculated between the tumor and contralateral white matter in two cases. In three patients, proton MR spectroscopy was performed using a single voxel technique with either STEAM or PRESS sequences. The locations of the tumor were the thalamus and basal ganglia (n=8), deep white matter (n=3), and brain stem (n=1).Results Intratumoral hemorrhage was seen in four tumors. The tumors showed high-signal intensity or DWIs, having a wide range of ADC values of 0.53–1.30 (mean ±SD=1.011±0.29). The maximum rCBV ratios of glioblastoma were 10.2 and 8.5 in two cases. MR spectroscopy showed decreased N-acetylaspartate (NAA) and increased choline in three cases. The MR findings of glioblastoma in children were: a diffusely infiltrative mass with hemorrhage involving the deep cerebral white matter, thalami, and basal ganglia. Conclusion Diffusion/perfusion MR imaging and MR spectroscopy are very helpful in diagnosing glioblastoma, determining the biopsy site, and evaluating tumor recurrence.This paper was presented as a scientific contribution at the 39th Annual Congress of the European Society of Paediatric Radiology, Bergen, Norway, June 2002     

Blount's disease: Magnetic resonance imaging

To evaluate the information obtained by magnetic resonance (MR) imaging, the radiographic and MR investigations of nine patients treated for idiopathic tibia vara were reviewed in retrospect. There were six unilateral and three bilateral cases (12 tibiae). Initial radiographs of each patient were assigned a stage according to Catonné's classification. MR imaging was performed with a 0.5- or 1.5-T apparatus. Bony epiphyses were poorly developed in all cases. The cartilaginous component of the epiphyses compensated partially (6/12 cases) or completely (6/12 cases) for the collapse of the physes. In two cases an abnormal area was found between the medial meniscus and the cartilaginous portion of the epiphysis. An abnormally large medial meniscus was noted in four cases; an abnormal signal in the medial meniscus was seen in two cases. MR imaging has several advantages over plain film: it uses no ionizing radiation, it shows the shape of the ossified and cartilaginous epiphysis, and it demonstrates meniscal and physeal abnormalities. MR imaging may influence the choice of treatment.     

Cerebral spinal fluid flow, venous drainage and spinal cord compression in achondroplastic children: impact of magnetic resonance findings for decompressive surgery at the cranio-cervical junction

In order to investigate the diagnostic properties of MRI of the brain and spine in achondroplastic children with regard to decompressive surgery, 25 patients were examined by conventional morphological and by “functional” imaging of CSF flow and magnetic resonance angiography (MRA) of the veins and sinuses at the cranial base following a special protocol. The results were compared to those from age-matched controls and were correlated with each other and retrospectively with the neurological findings. Measurements of distances and angulations at the cranio-cervical junction (CCJ) from MR scans showed similar values to those from conventional radiographs and CTs and thus can be used without correction for spatial distorsion. Signs of cervical medullary compression, myelomalacia and intramedullary cyst formation were found in six, seven and three children respectively. These alterations correlated significantly with each other (P < 0.05). Semiquantitative evaluation of CSF flow demonstrated interruption of CSF pathways at the CCJ, which correlated with CCJ narrowing (P < 0.05). MRA showed a significant narrowing of the jugular foramina with a variable compensatory enlargement of the emissary veins and a significant reduction of the total outflow area (P < 0.01). There were no significant correlations between these MR changes and neurological deficits. Conclusion Due to this unexpectedly poor correlation between magnetic resonance and clinical findings in achondroplastic children, the present role of magnetic resonance in the clinical setting is limited to the demonstration of spinal cord compression in individual cases. In three of our patients with prominent neurological abnormalities, the severe changes demonstrated by magnetic resonance imaging strongly supported the indication for surgical decompression. Received: 13 October 1999 and in revised form: 28 March 2000 and 2 May 2000 / Accepted: 7 May 2000