Relevance of MRI for management of non-displaced lateral humeral condyle fractures in children

INTRODUCTION

The treatment for non-displaced (<2 mm displacement) fractures of the lateral humeral condyle in children is controversial. Most studies recommend non-surgical treatment. However, plain radiographs are not sufficient to evaluate extension of the fracture line through the articular cartilage. This explains the high frequency of secondary displacements and non-unions, despite well-conducted conservative treatment. We hypothesized that MRI could be used to analyse whether the fracture is complete or incomplete. This could help to determine whether surgical or conservative treatment is indicated.

MATERIAL AND METHODS

This prospective study enrolled children being treated for a non-displaced (< 2 mm gap) fracture of the lateral humeral condyle. All patients were treated with a long-arm cast in the emergency room. An MRI was done later on without sedation. A specific protocol was used to reduce the duration of the examination. T2-weighted and proton density fat-saturated sequences were used.

RESULTS

Twenty-seven patients were enrolled: 16 boys and 11 girls with a mean age of 5 years (2-10). The MRI was performed an average of 7 days (1-23) after the fracture. The MRI could not be interpreted in two cases because the child had moved during the examination. In the other 25 patients, the fracture was incomplete in 17 patients and complete in 8 patients. Two children had secondary displacement diagnosed 7 and 11 days after the fracture event. These two patients underwent open reduction and internal fixation. There was no correlation between patient age and the fracture being complete or incomplete. There were no cases of non-union.

CONCLUSION

MRI appears to be a reliable method for determining whether the fracture line is complete or incomplete. It can be performed without sedation, even in children as young as 2 years of age. Use of an injury-specific MRI protocol reduces the length of the examination, thereby improving its performance. We recommend that it be used to analyse non-displaced fractures of the lateral humeral condyle in children.

LEVEL OF EVIDENCE

3 Prospective study.

[Severe nutritional rickets in young children: Resurgence of an old disease]

Nutritional rickets remains a significant public health issue for children worldwide. Although it has almost disappeared in industrialized countries following routine vitamin D supplementation, recent evidence suggests an increasing incidence, especially in young children. In addition to the classical clinical consequences on bone and the growth plate, rickets may also be associated with life-threatening neurological and cardiac complications in the most severe forms. Consequently, early screening and treatment are required. Here, we report the case of a 2-year-old child who presented with severe nutritional rickets associated with seizure and cardiomyopathy. Family screening revealed rickets in all the siblings. This case report emphasizes the importance of being aware of this disease, notably in population with sociocultural risk factors.

[Biliary peritonitis after traumatic rupture of a choledochal cyst]

Choledochal cysts are rare congenital malformations of the biliary tract. Traumatic rupture of a choledochal cyst can be misleading. An 11-year-old boy was admitted for peritonitis and intestinal occlusion after blunt abdominal trauma, evolving over 48 h. Laparotomy revealed bile ascites and a suspected duodenal perforation. After referral to our center, a CT scan showed a perforated choledochal cyst. Six months later, a complete excision of the cyst was successfully performed. This treatment is mandatory because of the risk of further complications such as lithiasis, pancreatitis, cholangitis, biliary cirrhosis, and malignant transformation (cholangiocarcinoma).

Prognosis value of early diffusion MRI in Legg Perthes Calvé disease

PURPOSE

To evaluate diffusion MRI of the proximal femoral epiphysis and metaphysis as a prognosis factor in Legg Calvé Perthes (LCP) disease.

METHODS

Thirty-one children (mean age 5.5 years, range 2.5-10.5) with unilateral LCP were included in a prospective, consecutive series. Radiographs were analysed and classified as per Herring criteriae. Mean follow-up was 19 months (range 6-30). Forty-nine MRI scans were performed at either the condensation or fragmentation stage. Apparent Diffusion Coefficient (ADC) of both the femoral epiphysis and metaphysis were measured bilaterally and ADC ratio were calculated, then compared to the Herring group.

RESULTS

Sixteen hips were rated Herring A or B, 3 Herring B-C and 12 Herring C. ADC was increased in affected hips compared to unaffected sides, both at the femoral epiphysis (P<0.001) and metaphysis (P<0.0001). ADC ratio of the femoral metaphysis was positively correlated to Herring classification: if superior to 1.63, it was associated with a bad prognosis (Herring B-C or C) (P=0.0017, sensitivity=89%, specificity=58%). Interobserver reliability of ADC measurement was excellent. The 1.63 threshold could be determined as early as the condensation stage.

CONCLUSIONS

Diffusion presents several advantages including being non radiating and non invasive. It does not need contrast medium administration and it can be performed without anaesthesia. The origin of the increased ADC remains unknown. Basically, it reflects molecular changes (true diffusion) but it is also influenced by the vascular supply (pseudo-diffusion). ADC ratio could provide an early prognosis before Herring classification is applicable.

LEVEL OF EVIDENCE

Level III. Prospective uncontrolled study.

Value of diffusion-weighted images in differentiating mid-course responders to chemotherapy for osteosarcoma compared to the histological response: preliminary results

BACKGROUND

Preoperative diffusion-weighted MRI (DW-MRI) has been described as an efficient method to differentiate good and poor responders to chemotherapy in osteosarcoma patients. A DW-MRI performed earlier during treatment could be helpful in monitoring chemotherapy.

OBJECTIVE

To assess the accuracy of DW-MRI in evaluating response to chemotherapy in the treatment of osteosarcoma, more specifically at mid-course of treatment.

MATERIALS AND METHODS

This study was carried out on a prospective series of adolescents treated for long-bone osteosarcoma. MR examinations were performed at diagnosis (MRI-1), at mid-course of chemotherapy (MRI-2), and immediately before surgery (MRI-3). A DW sequence was performed using diffusion gradients of b0 and b900. The apparent diffusion coefficients (ADC1, ADC2, ADC3, respectively), their differentials (ADC2 - ADC1 and ADC3 - ADC1), and their variation (ADC2 - ADC1/ADC1 and ADC3 - ADC1/ADC1) were calculated for each of these three time points.

RESULTS

Fifteen patients were included. Patients with no increase in ADC showed a poor response to chemotherapy on their histology results. At mid-course, the three calculated values were significantly different between good and poor responders. ADC2 - ADC1 enabled us to detect, with 100% specificity, four out of seven of the poor responders. There was no significant difference in the values at MRI-3 between the two groups.

CONCLUSION

DW-MRI performed both at baseline and mid-course of neoadjuvant chemotherapy is an efficient method to predict further histological response of osteosarcoma. This method could be used as an early prognostic factor to monitor preoperative chemotherapy.

[Unusual fetal teratoma presenting as a posterior mediastinal cyst]

Mediastinal cysts are uncommon prenatal findings. As isolated and non-compressing entities, they don't compromise the course of gestation. Massive lesions can compress vital structures, resulting in fetal demise. Thus, close follow-up with sonographic monitoring is recommended until birth. Non-hydroptic fetuses can be managed expectantly. Definitive etiology is known after surgical resection only. We present the first case of posterior mediastinal teratoma associated with severe vertebral abnormalities. After CT scan and fetal MRI, medical termination of pregnancy was decided. Histological examination revealed an immature teratoma. With this unique case report, we discuss the optimal prenatal management of mediastinal cysts.

Ovarian masses in adolescent girls

Ovarian masses are the most frequent gynecological pathology seen in adolescent girls. Functional or organic tumors of the ovary are usually benign and the incidence rises with age. Most cysts are functional and adnexal torsion is the main complication, but a malignant etiology must nevertheless always be eliminated. The clinical presentation is quite variable. Ultrasonography is the investigation of choice: the sonogram will reveal a strictly fluid, benign functional cyst, suggest an adnexal torsion, and provide evidence of a heterogeneous mass. Emergency surgery is indicated only in the case of suspected ovarian torsion, in order to perform detorsion. In all other cases, serum tumor marker measurements will orient the diagnosis and MRI is an essential complement to imaging of tumors with heterogeneous solid components. Surgery and histopathological examination then determine the stage and the benign or malignant nature of the mass. Ovarian tumors are classified by the World Health Organization based on the cell of origin into epithelial tumors, germ cell tumors and sex cord-stromal tumors. Surgery should always follow oncological standards and be as conservative as possible to preserve future fertility.

[Pulmonary sequestration and enteric cyst, 2 expressions of the same abnormality]

We report the case of an 18-month-old boy operated on for a right lower lobe bronchopulmonary sequestration. At the immediate postoperative check-up, a septic right thoracic effusion appeared, connected to a cystic mediastinal retrocrural formation on CT. After a drainage attempt and medical therapy, the abdominal lesion was resected. Histological examination showed that the cyst cavity was lined with pseudostratified non-ciliated epithelium, without cartilage, consistent with an enteric cyst. Regardless of the embryological theory, a literature review confirmed that in presence of one of these two lesions, one should systematically look for the other.

[Evolution of the pelvis and hip throughout history: from primates to modern man]

The evolution to a bipedal mode of locomotion was accompanied by a verticalization of the spine and a modification in the shape of the pelvis: horizontal curvature and sagittal rotation. Phylogenesis meets ontogenesis: flat bones in fetuses similar to the monkey, australopithecus features at birth and "human-like" features by 7 or 8years of age. These anatomical modifications explain the characteristics of human bipedalism: stable, economical, with hip and knee extension in the standing position with little lateral motion. Some pathologies induce a regression to a more archaic mode of bipedal locomotion.

[The chronically limping child]

Chronic limping in children usually indicates the presence of an underlying organic lesion. Clinical evaluation establishes the site and type of limping. It may suggest a neurological or mechanical lesion or locoregional etiology at the level of the hip or pelvis. Plain radiographs and ultrasound are firstline imaging techniques. The diagnosis may be delayed either due to ignorance of age-specific entities or false positive or negative results on plain films and ultrasound. MRI now plays a major role for diagnosis. Multiple potential underlying etiologies including trauma, infections, arthritides or tumors are best evaluated with MRI. The MRI examination should not be limited only to the hip joint.

[Unusual association of chylopericardium and aortic hypoplasia in a neonate]

We report the case of a neonate with two very rare anomalies: primary chylopericardium and diffuse hypoplasia of the thoraco-abdominal aorta. The presentation on the 16th post-natal day was with dyspnoea and refusal to feed. The initial clinical examination revealed hepatomegaly and weak femoral pulses. 2D ultrasound gave a diagnosis of a large compressive pericardial effusion combined with moderate hypoplasia of the aortic isthmus. Emergency pericardial drainage removed 80ml of chylous liquid. Following prolonged parenteral nutrition, the pericardial effusion stabilised. A mechanism of diffuse vascular disease affecting the aorta and the lymphatic system is suggested.

Long-term effects on tibial growth after intraosseous infusion: a prospective, radiographic analysis

BACKGROUND

Evaluate, by radiographic analysis, tibial growth after an intraosseous infusion (IOI) in a pediatric population.

METHODS

We performed a prospective simple blind study, between January 1, 1994, and July 1, 2001, which included pediatric patients who needed an intraosseous trocar in emergency situations. During the follow-up, roentgenographs were performed. On each radiologic view, different measurements were carried out: anterior and lateral tibial length, anterior and lateral width at 2 diaphyseal levels. We compared the anterior length values to those published in the Anderson et al tables. When only one tibia was punctured, the mean measurements were compared with the control leg measurements using a paired t test.

RESULTS

The initial population included 78 patients. Of these 78 subjects, 42 died, 10 families could not be contacted, and one refused to participate. Two children were excluded because they had other conditions that could influence tibial growth. The study included 23 children. The puncture site was the proximal tibia. The mean age was 18.6 months at the time of IOI, the mean time of infusion was 5 hours, and the mean perfused volume was 225 mL. The mean radiologic follow-up time was 29.2 months. When compared with the Anderson et al tables, all the anterior length values were within the 95% confidence interval. For the other measurements, the statistical analysis showed no significant difference between punctured and control legs.

CONCLUSION

There is no long-term effect on tibial growth after an IOI when the IO trocar is properly placed.

[Value of MR imaging of the fetal kidney]

Sonography is the imaging modality of choice for initial evaluation of the fetus. However, the role of MR imaging for fetal evaluation is expanding. Based on a review of seven cases, the role of MRI to further characterize renal abnormalities detected at US, especially hyperechoic kidneys, is demonstrated.

[Intermittent ureteropelvic junction obstruction and aberrant vessel to the lower pole of the kidney in children]

Intermittent ureteropelvic junction obstruction in children is a distinct clinical syndrome, it is often associated with an anteriorly crossing aberrant vessel to the lower pole of the kidney. The presence of these vessels increases the risk of complication and requires surgical management. CT scan is already the best exam to find these vessels in adults before treatment. It seems to be also efficient in children. This case report illustrates this indication.

Personalised mechanical properties of scoliotic vertebrae determined in vivo using tomodensitometry

This in vivo study investigated the mechanical properties of apical scoliotic vertebrae using computed tomography (CT) and finite element (FE) meshing. CT examination was performed on seven scoliotic girls. FE meshing of each vertebral body allowed automatic mapping of the CT scan and the visualisation of the bone density distribution. Centroids and mass centres were compared to analyse the mechanical properties distribution. Compared to the centroid, the mass centre migrated into the concavity of the curvature. The three vertebrae of a same patient had the same body migration behaviour because they were located at the curvature apex. This observation was verified in the coronal plane, but not in the sagittal plane. These results represent new data over few geometrical analyses of scoliotic vertebrae. Same in vivo personalisation of mechanical properties should be performed on intervertebral discs or ligaments to personalise stiffness properties of the spine for the biomechanical modelling of human torso. Moreover, do this mechanical deformation of scoliotic vertebrae, that appears before the vertebral wedging, could be a predictive tool in scoliosis treatment?

In vivo quantitative analysis of scoliotic vertebrae

An in vivo method based on CT images and finite element meshing had been developed to quantify and visualize the bone density distribution of scoliotic vertebrae. CT examination (axial acquisition of the apical, superior and inferior adjacent vertebral bodies) had been performed on seven girls presenting an idiopathic scoliosis. Using an in-house image processing software and the pre-post processor Patran, a surfacic finite element mesh of each body slice was proposed allowing an automatic mapping of the cancellous bone slices and a volumic mesh for the bone density distribution visualization. In the coronal plane, compared to the body geometrical centre, the body mechanical centre was shifted forward in the concavity of the curvature for six patients and in the convexity for one patient. For each patient, this shift forward was made in a same way for the three vertebrae. In the sagittal plane, the body mechanical inertia centre was shifted forward in the posterior side for 12 vertebrae, in the anterior side for 3 vertebrae and was not shifted forward for 6 vertebrae. This shift forward was made in the anterior side for the inferior adjacent vertebra. The shift forward by slice was made in a same way for each slice, excepted at the end plates. Besides, one can observe that the scoliotic deformation evolution seemed to modify the mechanical property distribution. The results may also suggest predictive criteria of evolution of the scoliotic deformities.

[Imaging of the hip in healthy children in MRI: evaluation of the acetabular coverage]

PURPOSE

To define with MR imaging a reference value for acetabular coverage on coronal and sagittal images for a population of healthy children.

MATERIALS AND METHODS

36 children (72 hips) where prospectively studied over 1 year. T1-weighted spin-echo images in both coronal and sagittal planes were obtained. Slice thickness was 4 mm. Measurement of acetabular coverage (AHI: Acetabular-Head Index) was made in both planes with two different landmarks: bone and cartilage. Study of the evolution with age was made.

RESULTS

The acetabular coverage is symmetrical and decreases with age. Its measurement is reproducible.

CONCLUSION

This study shows that measurement of acetabular coverage (AHI) is easily obtained at MR imaging and is reproducible. We suggest 83 (mean 1SD) as the inferior limit for AHI based on cartilage measurements. We introduce sagittal values, never published. We believe that MR, by its ability to demonstrate the cartilaginous surfaces, will play a major role in the true understanding of the anatomical relationship between the femoral head and the acetabulum.

Tomodensitometry measurements for in vivo quantification of mechanical properties of scoliotic vertebrae

OBJECTIVE

This in vivo study investigated the mechanical properties of scoliotic vertebrae especially in the apical zone.

DESIGN

A method based on computed tomography images and finite element meshing had been developed to quantify and visualise the bone density distribution of scoliotic vertebrae.

BACKGROUND

Most of scoliotic studies performed considered only geometrical parameters.

METHOD

Computed tomography examination had been performed on 11 girls presenting idiopathic scoliosis. Using in-house image processing software and the pre-post processor Patran, a finite element mesh of each vertebral body and a mapping of each cancellous bone slice were proposed allowing the bone density distribution to be visualised. The mechanical properties were derived from predictive relationships between Young's modulus and computed tomography number. Geometrical (unit mass) and mechanical centres were calculated and compared in order to quantify the role of mechanical property distribution on the apex zone of the scoliotic spine.

RESULTS

In the coronal plane, compared to the geometrical centre, the mechanical centre was shifted forward in the concavity (0.54 mm) of the curvature except for two vertebrae. In the sagittal plane, the mechanical centre was shifted forward in the back (0.26 mm) except for three vertebrae. The shift forward by slice was made in a same way for each slice (0.63 mm), except at the end plates (0.58 mm).

DISCUSSION

The result values obtained were small but significant because the curvatures were low and the vertebrae were not wedged. Besides, one can observe that the scoliotic deformation evolution seemed to modify the mechanical property distribution.

RELEVANCE

This study suggested the following question: Could these CT measurements be a predictive tool in scoliosis treatment?

Three-dimensional analysis of clubfoot deformity by computed tomography

The bony pathoanatomy of clubfoot has been assessed by a three dimensional reconstruction of transverse CT images obtained from 27 feet in children aged 3-10 years. Principal axes of the bones were determined to quantitate interosseous deformity, while visual inspection of the reconstructed images demonstrated intraosseous deformity. "Medial spin" and midfoot adduction were analyzed on the AP view of the foot ("top" view), while hindfoot pronosupination was analyzed on the AP view of the ankle (posterior view). This technique allows visualization of deformities which normally cannot be analyzed on plain radiographs, and also shows that a variety of interosseous relationships make up the clinical entity known as clubfoot. Abnormal talar pronation ("intorsion") was an unexpected finding of this three dimensional analysis.

[Urination disorders revealing posterior urethral valve: radiological aspects]

Posterior urethral valves represent the most common form of congenital urethral obstruction; they are due to the presence of membranous recesses within the posterior urethra. Their consequences on the lower and upper urinary tract depend on the importance of the obstacle. Moderate forms have a late clinical onset in children who present with voiding disorders and a normal upper urinary tract; in such cases, the diagnosis is difficult since typical features are absent on the urethrocystogram. Radiological signs of urethral valves should be differentiated from congenital urethral strictures which are not obstructive and from bladder dysfunctions which modify both the bladder and the urethra during micturition.

[Thoracic ultrasound]

Ultrasound exploration of the thorax is a very useful imaging method in children. For adults, it is useful for pleural effusion, study of the diaphragm and to guide percutaneous puncture of targeted pleuro-parietal, mediastinal or peripheral parenchymal sites. Thoracic ultrasound remains underused, particularly as a bedside exploration technique or in emergency or intensive care situations.

Mesoblastic nephroma: prenatal ultrasonographic and MRI features

Antenatal detection of mesoblastic nephroma by US is possible. Reviewing the literature, we found 19 previously reported cases, only 1 of which underwent prenatal MRI. We present a further case diagnosed by US and confirmed with MRI. The imaging findings and differential diagnoses are discussed. Early and correct detection of this rare entity is of great interest, as it may facilitate prevention and management of severe obstetric and neonatal complications such as polyhydramnios and prematurity. MRI can help to evaluate the origin and the morphological features of a fetal abdominal mass.

Congenital pseudarthrosis of the clavicle and thoracic outlet syndrome in adolescence

A 15-year-old girl with thoracic outlet syndrome associated with congenital pseudarthrosis of the clavicle was examined. The indication for treatment of congenital pseudarthrosis of the clavicle is discussed.

Assessment of hindfoot deformity by three-dimensional MRI in infant club foot

In 12 infants aged under 16 months with unilateral club foot we used MRI in association with multiplanar reconstruction to calculate the volume and principal axes of inertia of the bone and cartilaginous structures of the hindfoot.

The volume of these structures in the club foot is about 20% smaller than that in the normal foot. The reduction in volume of the ossification centre of the talus (40%) is greater than that of the calcaneus (20%). The long axes of both the ossification centre and the cartilaginous anlage of the calcaneus are identical in normal and club feet. The long axis of the osseous nucleus of the talus of normal and club feet is medially rotated relative to the cartilaginous anlage, but the angle is greater in club feet (10° v 14°). The cartilaginous structure of the calcaneus is significantly medially rotated in club feet (15°) relative to the bimalleolar axis. The cartilaginous anlage of the talus is medially rotated in both normal and club feet, but with a smaller angle for club feet (28° v 38°). This objective technique of measurement of the deformity may be of value preoperatively.

Assessment of hindfoot deformity by three-dimensional MRI in infant club foot

In 12 infants aged under 16 months with unilateral club foot we used MRI in association with multiplanar reconstruction to calculate the volume and principal axes of inertia of the bone and cartilaginous structures of the hindfoot. The volume of these structures in the club foot is about 20% smaller than that in the normal foot. The reduction in volume of the ossification centre of the talus (40%) is greater than that of the calcaneus (20%). The long axes of both the ossification centre and the cartilaginous anlage of the calcaneus are identical in normal and club feet. The long axis of the osseous nucleus of the talus of normal and club feet is medially rotated relative to the cartilaginous anlage, but the angle is greater in club feet (10 degrees v 14 degrees). The cartilaginous structure of the calcaneus is significantly medially rotated in club feet (15 degrees) relative to the bimalleolar axis. The cartilaginous anlage of the talus is medially rotated in both normal and club feet, but with a smaller angle for club feet (28 degrees v 38 degrees). This objective technique of measurement of the deformity may be of value preoperatively.

In vivo determination of homogenised mechanical characteristics of human tibia: application to the study of tibial torsion in vivo

OBJECTIVE: The study presents a method allowing the in vivo homogenised characteristics of the tibiae of children to be assessed. DESIGN: Studies have been performed on two groups of children: six normal children, aged from 5 to 16 yr, and on four children, aged from 8 to 11 yr with tibial deformities. We analysed the tibial transverse sections from CT scans performed on the left tibia of each child. BACKGROUND: Most tibial torsion studies have only been based on geometrical parameters. Our study integrated mechanical and geometrical considerations. METHODS: The finite element models and integration of mechanical properties were performed from CT scans. Then homogenised mechanical characteristics (tensile stiffness, flexural stiffness and torsional stiffness) were calculated. RESULTS: The homogenised mechanical characteristics decrease between 20 to 80% of the tibial length. The values increased with age for both groups of children. Children with abnormalities seem to have values of tibial rigidities comparable with those of normal tibiae. CONCLUSIONS: By considering the mechanical and geometrical properties of the tibia in our study, we showed that the bone stiffness of children is not altered with torsional deformities. RELEVANCE: Torsional tibial abnormalities of children are a frequent phenomenon which may have important consequences on gait and joints. The method developed could be used as an objective assessment of bone rigidities for analysing tibial disorders such as torsional abnormalities of varying severity.

Diagnostic approach to mediastinal masses

Mediastinal masses represent a vast group of tumours and pseudo-tumours which can involve the various compartments of the mediastinum. The authors propose a radiologic diagnostic approach starting from the plain thoracic radiograph with study of the mediastinal lines and oesophageal transit and going on to the classifications made possible by modern CT and MR imaging. The proposed diagnostic procedure is based on nine mediastinal lines and two 'threads of Ariadne' which are the compartments where the masses are located and their behaviour at CT (densitometry before and after administration of an iodinated bolus) and at MRI (T1, T2, gadolinium-enhanced T1-weighted sequences). The definitive aetiological diagnosis may be established by surgery, but also in certain cases by percutaneous needle biopsy.

[Autoimmune hemolytic anemia associated with a mature ovarian teratoma]

The association of autoimmune hemolytic anemia and mature teratoma of the ovary is rare, particularly in childhood, but must be known and looked for since the treatment of teratoma allows to cure anemia as well.

CASE REPORT

A 9 year-old girl was admitted for hemolytic anemia. The etiologic work-up revealed an autoimmune mechanism (IgG autoantibodies with complement), as well as an ovarian tumor after ultrasound sonography of the abdomen and pelvis. Surgical excision of the tumor was complete and uncomplicated. Pathological examination concluded to a mature teratoma. Anemia, as well as the signs of autoimmunity, disappeared a few weeks later and the child is doing well with several months of follow-up.

CONCLUSION

This second reported pediatric case shows that an ovarian teratoma should be searched for with ultrasound sonography in any girl presenting with autoimmune hemolytic anemia, since surgical excision is sufficient to cure both anemia and the tumor.

Imaging evaluation of subluxation in Legg-Calvé-Perthes disease: magnetic resonance imaging compared with the plain radiograph

The aim of the study was to evaluate the advantages of magnetic resonance imaging (MRI) in determining subluxation in Legg-Calvé-Perthes (LCPD) disease. Twenty-six patients with unilateral LCPD received 33 MRI and plain radiographs. For each patient, acetabulum head index (AHI) was measured on both hips (affected and unaffected) in a blinded fashion. Measurements were made from the cortical bone margin on the plain radiograph and from the cartilaginous surfaces on MRI. On the unaffected side AHI was 92.8% on the plain radiograph and 85% on MRI. On the affected side, AHI was 87% on the plain radiograph and 77% on MRI. These differences were statistically significant. With regard to the unaffected side, the femoral head should be considered subluxated if AHI is less than 86% on the plain radiograph and less than 77% on MRI. On the affected side, in 14 cases the femoral head was well-contained on both the plain radiograph and MRI. In 11 patients the femoral head was subluxated both on the plain radiograph and on MRI. In 8 patients the femoral head was well-contained on the plain radiograph but subluxated on MRI. This was due to thickening of the cartilaginous portion of the femoral head, which was clearly seen on MRI. MRI appeared to be more sensitive in determining the subluxation of the femoral head during the active phase of LCPD.

Disappearing suprarenal masses in fetuses and infants

This paper presents 12 infants (9 boys, 3 girls) in whom the diagnosis of a suprarenal mass (10 left, 2 bilateral) was made on antenatal sonography. All were otherwise healthy neonates who were born at term after a normal pregnancy, labor and delivery. The masses ranged from 1 to 3.5 cm in diameter on initial scans at gestational ages of 19-35 weeks. Eleven masses were hyperechoic and 4 of these contained small, well-defined cysts. The 12th was hypoechoic. Follow-up sonography showed complete disappearance of the mass antenatally in 1 case and postnatally by 4-6 months in 5 cases; there was marked diminution in the size of the mass by 2 months of age in 4 infants, by 4 months in 1 case and by 15 months in 1 case. Eleven were managed nonoperatively. Laparotomy (after disappearance of the mass) in the 12th case revealed only some fibrous tissue. The 11 echogenic masses resemble previously reported imaging findings in infants with histologically proven intra-abdominal sequestrated lung. Conservative management with careful sonographic follow-up should, therefore, be considered in otherwise healthy fetuses or neonates with these imaging findings. We are less certain what the hypoechoic mass represented.

[Clinical course and treatment of pleural empyema in children]

BACKGROUND

Purulent pleurisy has become rare. It is often masked by previous antibiotic treatment so that functional prognosis may be poor.

PATIENTS AND METHODS

Twenty children with purulent pleurisy of the large cavity admitted from 1987 to 1993 were included in the study: there were nine infants (age 5 to 18 months) with pleuro-pulmonary staphylococcal infection (group I) and 11 children (4-13 years) (group II). Clinical, biological, bacteriological and radiologic findings were analysed retrospectively as was the outcome.

RESULTS

Patients of group I were admitted in poor general condition. X-ray showed moderate effusion and characteristic signs of staphylococcal infection. The bacteria identified in seven patients (77%) was S aureus. Recovery was rapid with antibiotics and simple local treatment. X-rays were normal two months after hospital discharge in seven patients (77%). One infant presented cicatricial bullous emphysema which required segmental resection. Patients of group II were admitted for moderate respiratory signs after a relatively long delay (14 days) since the onset of symptoms. X-rays showed considerable effusion in all and mediastinal shift in five patients (45%). Streptococcus pneumoniae was identified in one patient only. Local treatment of empyema was difficult; the effusion, already fibrinous, required repeated use of chest tubes in eight cases and surgical decortication in three. X-rays, performed 2 months after hospital discharge, were normal in only three patients. Long-term course was nevertheless favorable since chest X-rays at 5 months were normal in all children of both groups.

CONCLUSIONS

Early recognition of purulent pleurisy is important in children aged over 3 years to ensure effective drainage before the effusion becomes fibrinous. All patients in whom the first tube was inserted after more than 10 days had a difficult follow-up requiring repeated chest drainages or surgery. Ultrasonography was a useful aid for diagnosis and local treatment. Computed tomography was useful for adapting treatment after several days of course.

[Persistence of spongy myocardium: apropos of a case]

A two and a half year old child was admitted to hospital with peripheral cyanosis. Echocardiography revealed severe dilated cardiomyopathy affecting both ventricles with abnormally hypertrophied and irregular myocardial walls. The pulmonary hypertension was suprasystemic with raised pulmonary resistances. The magnetic resonance imaging and angiography confirmed the diagnosis of persistence of spongy myocardium. This is a rare abnormality due to the persistence of embryonic myocardium with a network of trabeculations and intertrabecular spaces as usually observed during echocardiography. This case is noteworthy because of the biventricular involvement and the absence of associated congenital cardiac malformation. The prognosis is characterised by a high risk of severe cardiovascular complications.

[How to manage a symptomatic ovarian follicular cyst in a female child?]

BACKGROUND

--Ovarian cysts are common in childhood but most are non functioning. Treatment of those follicular cysts that develop in young children may be difficult.

CASE REPORTS

Case no. 1.--A 1 1/2 month-old baby was admitted because of an acute abdominal syndrome. Ultrasonography showed a pelvic, heterogeneous mass without calcifications. Laparotomy showed right ovarian torsion with necrosis of a cyst requiring ovariectomy. At that time, there was an isolated increase in FSH after LHRH stimulation. A transitory premature thelarche without pubertal type response to LHRH was seen at the age of 3 months. Clinical and ultrasonographic controls remain normal with a follow-up of 1 year. Case no. 2.--A 4 yr 10 m-old girl was admitted because of an acute abdominal syndrome. Ovariectomy was necessary because laparotomy showed right ovarian torsion with necrosis of a cyst. Recurrent abdominal pain, 4 months later, was associated with an enlarged left ovary without sexual precocity. Gonadotropin were slightly increased after LHRH stimulation and the patient was given LHRH agonist that suppressed endogenous LHRH within 3 months. Clinical and ultrasonographic controls remain normal 1 year after cessation of treatment. Case no. 3.--A 19 month-old girl was admitted because of a genital hemorrhage with recent development of secondary sexual characteristics. Skeletal age was 2 yrs. Ultrasonography showed an enlarged uterus and a left ovarian cyst, heterogenous with calcifications. Plasma levels of estradiol were increased but gonadotropin were normal. Ovariectomy was performed, followed by disappearance of secondary sexual characteristics. However, the patient was given LHRH agonist at the age of 2 yr 7 mo because of recurrent pubertal activity.

CONCLUSIONS

--These cases underline the difficulty in treating follicular cysts in young girls. The possibility of cyst recurrence with manifestations of pubertal activity after ovariectomy lead to discuss indication of LHRH agonists for an undetermined duration.

Antenatal detection of subdiaphragmatic pulmonary sequestration: a case report

Extralobar pulmonary sequestration is part of the spectrum of bronchopulmonary foregut malformations. Usually found in the thorax, it may be located in the retroperitoneum. We report one case of subdiaphragmatic pulmonary sequestration detected by prenatal ultrasound, and diagnosed at surgery after birth. This case illustrates the diagnostic and therapeutic problems occurring during pregnancy and the neonatal period.

Osteoid osteoma: MR imaging versus CT

PURPOSE

To compare the performance of computed tomography (CT) and magnetic resonance (MR) imaging in diagnosis of osteoid osteoma.

MATERIALS AND METHODS

Nineteen patients with histologically proved osteoid osteoma underwent CT and MR imaging before excision of the lesion. CT and MR images were compared regarding lesion conspicuity and detection of marrow, soft-tissue, and/or synovial changes adjacent to the primary lesion.

RESULTS

CT was more accurate than MR imaging in detection of the osteoid osteoma nidus in 63% of cases. MR imaging was better than CT in showing intramedullary and soft-tissue changes in all cases. This may produce a misleading aggressive appearance on MR images. There was a statistically significant correlation between presence or absence of marrow or soft-tissue changes and treatment with antiinflammatory medications (P < .05).

CONCLUSION

CT remains the best imaging modality for diagnosis of osteoid osteoma. MR images should not be interpreted without reference to plain radiographs and CT scans if serious errors in diagnosis are to be avoided.

Percutaneous resection of osteoid osteoma under CT guidance in eight children

In eight children with suspected osteoid osteoma, a percutaneous resection under CT guidance was performed. The specific drill resection system we currently use includes a 7-mm-diameter toothed drill. Osteoid osteomas were located in the appendicular skeleton in seven children and in the spine (second lumbar vertebral body) in one. All eight patients were successfully treated with complete relief of pain. There was no recurrence of symptoms during a follow-up period of 8-35 months. CT guidance was accurate enough to allow a focal bone excision, and no subsequent bone repair was needed. Histological confirmation was obtained in all cases. This simple and safe technique, when feasible, seems to be an effective means of treatment of osteoid osteoma in children.

[Malignant neonatal tumors]

Malignant neonatal tumors are rare (2% of childhood cancers, 1-2 cases/30,000 births). However, specificities in diagnosis and therapy must be underlined at this period of life; furthermore, the possibilities of antenatal sonographic diagnosis are improving and it may contribute to increase their incidence. Topographic analysis allows etiologic investigations since these tumors have the same diagnostic features as compared with older children, except Pepper's syndrome and leukemias. Therapeutic management depends on a rather good prognosis and fragility of such newborn. Indeed, surgical excision is the main step of treatment. Radiotherapy must be avoided whenever possible. Chemotherapy may be indicated (metastatic or unresectable tumors, omission or delay of irradiation in brain tumors) and has to be elaborated cautiously, according to the peculiar physiology of the neonate. Whatever the therapeutic strategy is, neonatal homeostasis must be well balanced, which implies a multidisciplinary specialized team. Respecting these conditions will help to cure more than the present 50% and better for future well being of such children.

Osteoid osteoma: percutaneous resection with CT guidance

In 24 patients with presumed osteoid osteoma in the appendicular skeleton (n = 23) and lumbar spine (n = 1), percutaneous resection with a drill system and computed tomographic (CT) guidance was performed. In the procedure, a 7-mm-diameter toothed drill inserted over a guide wire is used to remove the nidus. Twenty-three patients were successfully treated. Histologic confirmation of osteoid osteoma was obtained in 19 cases. In one patient, open surgery with bone grafting and osteosynthesis was necessary because of inadvertent extensive bone resection resulting from damage to the drill. All patients have remained free of pain and recurrence for 3-24 months. Although the procedure was effective in all patients, the 7-mm diameter of the toothed drill may cause difficulty in small bones or even danger in areas such as the posterior vertebral arch. In locations such as the tubular bones of the lower extremity and the femoral neck, however, this technique is feasible and may become the treatment of choice for osteoid osteoma.

MR imaging in hemophilic arthropathy

20 children with hemophilia were examined with Magnetic Resonance Imaging (MRI) to determine if MRI could be used to assess hemophilic arthropathy, especially in the early stages. 28 joints of the appendicular skeleton were imaged, including 17 knees, 10 ankles and 1 elbow. The results were compared to clinical and plain radiographic assessments and to the surgical findings when synovectomy was performed. MRI is able to evaluate the components of hemophilic arthropathy such as fluid effussion, synovial hypertrophy, the status of the articular cartilage, and bony lesions. These lesions can be discovered at an early stage when plain radiographs are still normal. MRI seems to be useful for the selection of patients needing early treatment of hemophilic arthropathy and in monitoring response to therapy.

Percutaneous extraction of an osteoid osteoma of the lumbar spine under CT guidance

We report one case of percutaneous extraction of an osteoid osteoma of the lumbar spine under CT guidance. We describe the procedure of nidus extraction. This technique allows precise removal of the nidus with pathologic verification after extraction.