Volumes of the spinal canal and caudal space in children zero to three years of age assessed by magnetic resonance imaging: implications for volume dosage of caudal blockade.

BACKGROUND: The primary aim of this study was to objectively assess the different spinal and caudal volumes that are of interest for caudal block volume dosing. METHODS: Three directly assessed (volume of spinal canal/caudal space, volume of the dural sac and volume of spinal cord) and two derived volumes (volume of the epidural space and cerebrospinal fluid volume) were determined from magnetic resonance images (MRI) in 20 children (zero - three yr of age). The assessed volumes were correlated to age, height and weight. Furthermore, the volumes of the epidural space from caudal canal to three different clinically relevant target levels (L 1, Th 10 and Th 6) and the epidural volume of each individual spinal segment at the caudal, lumbar and thoracic levels were calculated. RESULTS: All volumes correlated in a linear manner to length and weight (R2 0.614 - 0.867) whereas a curvilinear correlation was associated with best curve fit for age (R2 0.696 - 0.883). The median volumes of the epidural space from caudal canal to L 1, Th 10 and Th 6 were 1.30 ml kg-1 (95%CI 1.08-1.51), 1.57 ml kg-1 (95%CI 1.29-1.81) and 1.78 ml kg-1 (95%CI 1.52-2.08), respectively. The median volumes of the epidural space per vertebral segment were Thoracic: 0.60 ml (95%CI 0.38-0.75); Lumbar: 1.18 ml (95%CI 0.94-1.43) and Caudal: 0.85 ml (95%CI 0.56-1.18). CONCLUSIONS: The spinal volumes of interest show a linear correlation to height and weight whereas a curvilinear correlation was found for age. The volume of the epidural space per segment was found to be significantly higher at the lumbar level compared with the caudal and thoracic levels.

Anterior dynamic ultrasound and Graf's examination in neonatal hip instability.

BACKGROUND: Discrepancy between neonatal hip morphology and stability has been reported in the literature. Comparative ultrasound studies on this issue are limited. PURPOSE: To compare neonatal hip instability, as assessed by dynamic ultrasound and clinical examination, with acetabular morphology, as assessed by Graf's method. MATERIAL AND METHODS: 536 newborn infants with clinical signs of hip instability, ambiguous findings at clinical hip examination, or positive risk factors for DDH were investigated with two ultrasound methods, the Graf method and anterior dynamic ultrasound, at an average age of 12 days. The hips were allocated to three groups according to the Graf result: A, normal (type Ia and b); B, borderline or immature (type IIa); and C, pathologic (type IIc and worse). Graf examination was compared with two diagnostic tests for instability, namely clinical examination by senior pediatric orthopedists and anterior dynamic ultrasound. RESULTS: According to Graf's method, 77% of the hips were normal, 20% borderline/immature, and 3% pathologic. On clinical hip examination, 82% were stable, 14% unstable, and 4% dislocatable. The dynamic ultrasound outcome was 88% stable hips, 10% unstable, and 2% dislocatable. Of the hips considered unstable or dislocatable on dynamic ultrasound, 21% had normal (type I) and 66% immature acetabular morphology according to the Graf method. Of the hips that were stable on dynamic ultrasound, only one (0.1%) was dysplastic according to the Graf method. Graf's examination showed the smallest number of normal hips, but also the fewest pathologic hips, with many indeterminate results that needed follow-up. CONCLUSION: Acetabular morphology correlated better to stability as assessed by dynamic ultrasound than to the clinical examination results, with fair to moderate agreement. Graf's examination resulted in a large number of indeterminate results that needed follow-up, but when used as the sole criterion for deciding treatment did not lead to a higher treatment rate than when the decision was based on clinical hip examination.

Neonatal hip instability: a prospective comparison of clinical examination and anterior dynamic ultrasound.

BACKGROUND: Ultrasound is increasingly being used to complement the clinical examination in assessing neonatal hip instability. The clinical examination, although highly sensitive in detecting hip instability, can lead to considerable overtreatment. PURPOSE: To compare anterior dynamic ultrasound and clinical examination in the assessment of neonatal hip instability and regarding treatment rates. MATERIAL AND METHODS: 536 newborn infants (out of a population of 18,031) were selected, on the basis of a combination of risk factors, clinical signs of hip instability or ambiguous clinical findings, to undergo an anterior dynamic ultrasound examination of the hip, by a method developed by our group. This examination, performed by one out of seven experienced examiners, was compared with the standard clinical hip examination conducted by one of four pediatric orthopedic surgeons. The clinical examination was carried out both prior to and within a few hours after the ultrasound examination. RESULTS: The clinical examination diagnosed 81.7% of the hips as normal, 14.5% as unstable, and 3.8% as dislocatable or dislocated. With the dynamic ultrasound method, the corresponding figures were 87.8%, 10.4%, and 1.8%, respectively. Use of the criteria of the clinical examination resulted in treatment of 147 infants. Using the dynamic ultrasound examination as a criterion meant that 87 infants would receive treatment. The calculated treatment rate was 0.85% when based on the clinical stress test and 0.49% when based on the dynamic ultrasound. CONCLUSION: The dynamic ultrasound results reduced the treatment rate by over 40% when used as a basis for the decision regarding treatment.

Pediatric PACS, Astrid Lindgren Children's Hospital at Karolinska Hospital, Stockholm, technical and practical aspects.

We present a filmless pediatric radiology department for the Stockholm area (1.8 million inhabitants) producing 50000 examinations per year. Seventy percent of the examinations are non scheduled, 50% are emergency cases out of office hours. The system is designed for high reliability operating with 99.7% uptime. A large number of daily conferences are held throughout the Children's Hospital at the various specialized departments, distributed through the intranet, with one pediatric radiologist attending. Instant reading is made in the majority of examinations and reports are available with images throughout the hospital including PC's at doctors rooms. The system uses conventional hardware and software with an open systems standard based approach. The system is highly appreciated by clinicians and has improved availability of radiology information.

The changed preliminary report: a repeatedly missed paediatric tibial tumour.

This report describes a malpractice case involving a delayed diagnosis of a malignant bone tumour in the proximal tibia in a 10-year-old child. This was caused by a combination of factors. The final report on the first examination failed to reach the patient files, and two subsequent X-ray exams failed to diagnose the tumour, due to misinterpretation in one and obscuring plaster of Paris in the other.

Tossed on the horn of humerus: a legal case report.

Radiological cases constituted 2% of the total number of legal cases in Sweden during 1996. The young man in this report accused a radiologist of having missed a fracture 7 years earlier based on a new radiology examination and report. In reality the latter report was incorrect and the patient had a rare exostosis that explained the clinical signs and symptoms. The alleged fracture was an epiphyseal line to a non-unified ossification centre at the tip of the unique exostosis.

Added copper filtration in digital paediatric double-contrast colon examinations: effects on radiation dose and image quality.

Paediatric double-contrast barium enema examinations are usually performed at high tube voltage, 102-105 kV. The aim of this study was to investigate how much the effective dose to the child could be reduced by increasing the X-ray energy further by adding copper filter in the beam, and if this dose reduction could be achieved without endangering image quality. Organ doses to an anthropomorphic phantom simulating a 1-year-old child was measured using thermoluminescence dosimetry for assessment of the effective dose and this value was compared with the energy imparted which was obtained from kerma-area product measurements. To verify that the image quality achieved with this added filtration was still diagnostically acceptable, the study included 15 patient examinations. Since the increased X-ray energy will most probably affect low-contrast objects, image quality was also evaluated with two different phantoms containing low-contrast objects. Effective dose for a complete examination can be decreased 44 % and energy imparted 77 % when a 0.3-mm copper filter is inserted in the beam at tube voltage 102 kV. The patient study did not show any significant deterioration of image quality, whereas phantom measurements of contrast-detail resolution and signal-to-noise ratio was marginally impaired by the added copper filtration. This technique is now in clinical practice for paediatric colon examinations.

Dynamic ultrasonography of the infant hip with suspected instability. A new technique.

PURPOSE: The combining of clinical examination of the infant hip with dynamic ultrasound (US) into one examination, performed by one examiner, should result in a sensitive test for hip instability. In this study a new method of dynamic US examination of the hip in newborn and very young children, that combined US with stress testing (BARLOW method) was tested. MATERIAL AND METHODS: A specially designed examination table, with a US probe holder, enabled the radiologist to perform a stress test of the hip according to BARLOW (using both hands), and simultaneously monitor it on US. Fifty-seven infants and young children were examined by this method, and compared with the GRAF method and clinical stress test. RESULTS: Our method allowed clear visualisation of the movement of the femoral head during the stress test, and was performed easily in patients under 3-4 months of age. CONCLUSION: The described method is easily adapted for one examiner with experience in US and in the clinical examination of the infant hip.

Nondisplaced and minimally displaced fractures of the lateral humeral condyle in children: a prospective radiographic investigation of fracture stability.

Subsequent displacement of nondisplaced or minimally displaced fractures of the lateral humeral condyle while immobilized in plaster may contribute to severe complications. The possibility of assessing the stability of such fractures may be a help in planning the initial treatment. Our prospective investigation of 112 children aged 1-11 years aimed at describing radiographic criteria for prognosticating the stability of the fractures. According to the radiographic findings, the fractures were allocated to one of three groups representing stable fractures, fractures with undefinable risk, and fractures with high risk of later displacement. All children were treated with splinting only. Sixty-five fractures were classified as stable and turned out to be so without exception. Displacement occurred in six of 35 (17%) of the fractures judged uncertain and in five of 12 (42%) of those judged unstable. The subsequent displacement was 1 or 2 mm, and in one case, 3 mm. The defined criteria were found to be efficient in separating the stable and the high-risk fractures with acceptable confidence. The group of fractures with undecided risk of subsequent displacement was fairly large--one third of the total material. The implication the findings may bear to the treatment strategy of fractures is analyzed in a work in progress.