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.

[Computed tomography in children with cystic fibrosis: The role of an expiratory protocol]. / Scanner thoracique chez l'enfant atteint de mucoviscidose : intérêt d'un protocole en expiration séquentielle pour réduire la dose d'irradiation.

INTRODUCTION: Chest computed tomography (CT) is essential to monitor lung disease in children with cystic fibrosis, but it involves recurrent exposure to ionizing radiation. The aim of this study was to compare the current complete CT protocol (volumetric end-inspiratory plus sequential expiratory acquisition) to a sequential expiratory acquisition protocol alone in terms of image analysis and ionizing radiation dose. METHODS: Seventy-eight CT scans from 57 children aged 5 to 18 years old were scored on the complete protocol images and on the expiratory sequential images only. Each CT protocol was scored independently, using the Brody scoring system, by two paediatric radiologists. RESULTS: Correlations between the Brody global scores of the two different CT protocols were very good (r=0.90 for both observers), for the bronchiectasis score (r=0.72 and 0.86), mucus plugging score (r=0.87 and 0.83), and expiratory trapped air (r=0.96 and 0.92). Total ionizing radiation dose was reduced, with the measured dose length product (DLP) reduced from 103.31mGy.cm (complete protocol) to 3.06mGy.cm (expiratory protocol) (P<0.001). CONCLUSION: An expiratory chest CT protocol was accurate in diagnosing early signs of CF disease and permitted significant reduction of radiation dose. This protocol would allow spacing out of complete CT scanning with its higher radiation dose and should be considered for the monitoring of lung disease severity in children with CF.

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]. / Rachitisme carentiel sévère du nourrisson : de nouveau d'actualité.

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.

[Unusual association of chylopericardium and aortic hypoplasia in a neonate]. / Association inhabituelle chez un nouveau-né d'un chylopéricarde et d'une hypoplasie aortique.

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.

[Biliary peritonitis after traumatic rupture of a choledochal cyst]. / Péritonite biliaire par rupture traumatique d'un kyste du cholédoque.

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).

[Thymoma in children: a rare and difficult diagnosis]. / Thymome de l'enfant : un diagnostic parfois difficile.

Thymoma is extremely rare within the pediatric age range, which could lead to delayed diagnosis. Based on the clinical case of a mediastinal tumor in an 8-year-old patient, we detail the key points in the management of this disease highlighted by our recent experience.

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.

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.

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?

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.

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.

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.

[Persistence of spongy myocardium: apropos of a case]. / Persistance du myocarde spongieux: à propos d'un cas.

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.

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?

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.

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.

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.

[Urination disorders revealing posterior urethral valve: radiological aspects]. / Troubles mictionnels révélateurs de valves de l'urètre postérieur: aspects radiologiques.

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.