Garry W. LeQuesne

The improved ultrasound diagnosis of hypertrophic pyloric stenosis

A prospective study of ultrasound in the diagnosis of idiopathic hypertrophic pyloric stenosis (IHPS) in 200 consecutive infants with persistent vomiting is reported. The criteria evaluated include measurements of the pyloric diameter, muscle thickness and canal length, and observing the function of the pylorus and gastric peristalsis in real-time. Using these ultrasonic criteria, the infants studied were assessed as 112 with IHPS and 88 normals. All the infants were followed up, and the method was 100% accurate, with no false positive or negative results. The statistics of the static measurements are included and show that the canal length is the only precise discriminator between a normal and an hypertrophied pylorus. The method is accurate, rapid and safe, allowing earlier diagnosis of IHPS. It should replace the barium meal in the evaluation of IHPS where the clinical diagnosis is in doubt.

Ultrasonic features of acute osteomyelitis in children

The ultrasonic findings in 38 children with osteomyelitis of the limb bones were analysed in four time-related groups based on the interval between the onset of symptoms and the ultrasonic examination. Deep soft-tissue swelling was the earliest sign of acute osteomyelitis; in the next stage there was periosteal elevation and a thin layer of subperiosteal fluid, and in some cases this progressed to form a subperiosteal abscess. The later stages were characterised by cortical erosion, which was commonly present in those who had had symptoms for more than a week. Concurrent septic arthritis was revealed in 11 patients, most frequently in association with osteomyelitis of the proximal femur or the distal humerus. Four weeks after clinical cure, ultrasonic examination showed no abnormalities. Ultrasonography is therefore a useful additional method for the diagnosis and assessment of osteomyelitis and its complications.

Slipped capital femoral epiphysis. Incidence and clinical assessment of physeal instability

In an unselected series of 55 cases of slipped capital femoral epiphysis (SCFE) we observed an incidence of 25% of epiphyseal reduction, mostly unintentional. Reduction indicated physeal instability and was associated with an effusion, detected by sonography on admission, and inability to bear weight. The true prevalence of instability may be higher since an effusion was noted in 33 cases (60%) on the initial sonographic assessment. Serial radiographs showed reduction in 12 (22%), with an average change of 15.1 degrees in the head-neck angle. Serial sonography showed reduction in 7 out of 20 cases (35%), with an average change of 3.7 mm in displacement. In two cases reduction was seen on sonography but not on radiography. Of the hips which showed subsequent reduction, 12 had had a bone scan on admission; three showed initial epiphyseal avascularity but only one progressed to symptomatic avascular necrosis. All stable hips had normal epiphyseal vascularity on the initial bone scan. This indicates the importance of injury from the initial displacement in causing avascular necrosis, rather than effusion, vascular compromise or iatrogenic injury from gentle repositioning. Physeal instability in SCFE is common and should be assessed clinically on admission. It is indicated by joint effusion or inability to bear weight. A slip is very unlikely to be unstable in a child able to bear weight and with no sonographic effusion.

Classification in slipped capital femoral epiphysis : sonographic assessment of stability and remodeling

In a prospective study of 26 hips in 21 patients with slipped capital femoral epiphyses (SCFEs), serial sonography was more sensitive than radiography in showing epiphyseal displacement and reduction. Reductions were associated with grossly visible hip joint effusions. The initial slips were reduced by treatment in seven of 11 hips with effusion. The 15 hips without effusion were unreduced. After stabilization and pinning, the effusion did not recur in any case. Sonography is sensitive and free from projectional errors in the assessment of metaphyseal remodeling. If any remodeling is present, the SCFE is at least three weeks in duration. A new classification into acute, acute-on-chronic, and chronic SCFEs is proposed, based on the objective sonographic data. Joint effusion represents physeal instability or recent progression, and remodeling is a sign of chronicity. An acute SCFE is characterized by effusion, whereas a slip without effusion but with remodeling is designated as chronic. An acute-on-chronic SCFE is associated with both effusion and remodeling. Joint effusion suggests that SCFEs should be operatively fixed and that displacement may diminish with traction or intraoperative positioning of the hip.

Ultrasonic signs of pelvic osteomyelitis in children

The ultrasonic findings were reviewed in 13 children in whom pelvic osteomyelitis was diagnosed by a positive99mtechnetium methylene diphosphonate (MDP) bone scan in conjunction with clinical and laboratory features of osteomyelitis. All patients presented with pain in the region of the hip joint. In six patients the ultrasound study was confined to the hip joint, and all six had normal findings. In seven patients the ultrasound study was extended to include the pelvis. Deep soft tissue swelling was demonstrated in six of these, including a periosseous abscess in one case. Ultrasonography was negative in one patient with a 5-week history, whose pelvic osteomyelitis was resolving at the time of the ultrasound study. Oedema of the obturator internus and externus muscles was observed in osteomyelitis affecting the pubis and ischium, and of the iliacus and/or the gluteus medius muscle in osteomyelitis of the ilium. In children presenting with hip pain who have a normal hip ultrasound study, extension of the ultrasound examination to include these four pelvic muscles may help to identify and document the progression of acute pelvic osteomyelitis.

Sonographically demonstrated thickening of the renal pelvis in children

Thickening of the wall of the renal pelvis has been attributed to infection, to rejection in allografts and to non-specific causes by different authors. We reviewed the clinical data, imaging studies and pathology of 35 patients with sonographically demonstrable thickening in 41 renal pelves of native kidneys. Our findings are that less than 50% of the patients had infection. The others had a wide variety of apparent causes for the thickening which include obstruction, surgery, edema induced by chemicals and other processes. Vesicoureteral reflux was demonstrated in 50% of the patients studied by cystography. We concluded that renal pelvic thickening is a non-specific finding.

Ultrasonography in slipped capital femoral epiphysis. Diagnosis and assessment of severity

We used ultrasonography to study 26 hips with slipped capital femoral epiphyses. In recently slipped epiphyses the ultrasound image revealed a step at the anterior physeal outline (mean 6.4 mm), diminished distance between the anterior acetabular rim and the femoral metaphysis (mean 4.3 mm) and an effusion. As metaphyseal remodelling progressed the physeal step decreased. The femoral neck appeared straighter in hips which had been symptomatic for longer than three weeks. It was possible to measure posterior epiphyseal displacement without projectional errors and the method was accurate in diagnosing minimal slip and in staging displacement. The suggested criteria are, less than 7 mm for a mild slip, 7 to 11 mm for a moderate slip and more than 11 mm for a severe slip. We recommend ultrasonography for the diagnosis, staging and follow-up management of slipped upper femoral epiphysis.

Renal length in chinese children: Sonographic measurement and comparison with Western data

The purpose of this study was to determine the normal range of renal length in Hong Kong Chinese children and compare it with Western data.

Bilateral synovitis in symptomatic unilateral transient synovitis of the hip An ultrasonographic study in 56 children

56 children with a clinical diagnosis of unilateral transient synovitis of the hip underwent bilateral sonographic assessment. On the anterior scan, the distance between the femoral neck and the fibrous joint capsule was measured. This distance, which we call the synovial capsular complex distance, was compared with age-dependent normal values. An increased distance was found in all 56 symptomatic hips (mean 10 mm, SD 1.8). This distance was also increased in 14 hips on the contralateral side (mean 8 mm, SD 1.6). An effusion was demonstrated in 53 symptomatic hips and in 8 hips on the contralateral side. These findings indicate that in one quarter of children with symptoms of unilateral transient synovitis the contralateral hip may have an increased synovial capsular complex distance due to synovial swelling or joint effusion, suggesting an asymptomatic synovitis. We therefore recommend a comparison of the synovial capsular complex distance on the symptomatic side with age-related normal values, in addition to a comparison with the asymptomatic hip.

Remodeling in slipped capital femoral epiphysis: sonographic assessment after pinning.

Twenty-one children and 26 hips with recent slipped capital femoral epiphysis (SCFE) underwent serial sonographic examination after operative fixation. The initial sonographic step at the anterior outline of physis decreased as a result of metaphyseal resorption. The first signs of resorption were evident 3 weeks after onset of symptoms; thereafter, the rate of resorption was 2 mm for each 3 weeks of follow-up. Finally, the physeal step was smooth and the anterior aspect of the femoral neck was straight. Sonography is accurate and free of projectional errors in assessment and classification of remodeling in SCFE.