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.

Metacarpophalangeal pattern profile analysis: useful diagnostic tool for differentiating between dyschondrosteosis, Turner syndrome, and hypochondroplasia.

PURPOSE: To assess the value of the metacarpophalangeal pattern profile (MCPP) analysis as a diagnostic tool for differentiating between patients with dyschondrosteosis, Turner syndrome, and hypochondroplasia. MATERIAL AND METHODS: Radiographic and clinical data from 135 patients between 1 and 51 years of age were collected and analyzed. The study included 25 patients with hypochondroplasia (HCP), 39 with dyschondrosteosis (LWD), and 71 with Turner syndrome (TS). Hand pattern profiles were calculated and compared with those of 110 normal individuals. Pearson correlation coefficient (r) and multivariate discriminant analysis were used for pattern profile analysis. Pattern variability index, a measure of dysmorphogenesis, was calculated for LWD, TS, HCP, and normal controls. RESULTS: Our results demonstrate that patients with LWD, TS, or HCP have distinct pattern profiles that are significantly different from each other and from those of normal controls. Discriminant analysis yielded correct classification of normal versus abnormal individuals in 84% of cases. Classification of the patients into LWD, TS, and HCP groups was successful in 75%. The correct classification rate was higher (85%) when differentiating two pathological groups at a time. Pattern variability index was not helpful for differential diagnosis of LWD, TS, and HCP. CONCLUSION: Patients with LWD, TS, or HCP have distinct MCPPs and can be successfully differentiated from each other using advanced MCPP analysis. Discriminant analysis is to be preferred over Pearson correlation coefficient because it is a more sensitive and specific technique. MCPP analysis is a helpful tool for differentiating between syndromes with similar clinical and radiological abnormalities.

Metacarpophalangeal pattern profile analysis as a tool for early diagnosis of Turner syndrome.

PURPOSE: To analyze the metacarpophalangeal pattern profile (MCPP) in a cohort of individuals with Turner syndrome (TS), and to assess its value as a tool for early diagnosis of TS. MATERIAL AND METHODS: Medical records and radiological material were collected of 71 patients with TS aged between 3 and 21 years. Forty-six patients received growth hormone therapy (33-66 microg kg(-1) day(-1)) and 14 of these were also treated with the anabolic steroid oxandrolone (1.25-3.75 mg day(-1)). A total of 233 frontal hand radiographs were studied and pattern profiles were calculated. Profiles of the TS patients were compared with those of 70 normal females. Mean pattern profiles were calculated for different age groups and extrapolated profiles for newborns and infants were developed. RESULTS: Our results confirm that patients with TS have a distinct MCPP which differs significantly from that of normal individuals. A bone-shortening gradient with increasing shortening from distal phalanges to metacarpals was demonstrated. We also showed that the MCPP in TS is a remarkably constant feature from 3 to 18 years. Pattern profiles did not differ significantly between the patients with 45,X and non-45,X karyotype. MCPP was not affected by treatment with growth hormone of growth hormone plus oxandrolone. Discriminant analysis yielded correct classification in 88%, of analyzed cases. CONCLUSION: TS individuals have a distinct hand pattern profile that is not age-related. MCPP analysis can be applied at any age and may facilitate early diagnosis of TS. Our study showed that MCPP analysis is a specific and sensitive method that should be considered as a routinely used tool for early diagnosis of TS in girls with unexplained short stature.

Metacarpophalangeal pattern profile analysis in Leri-Weill dyschondrosteosis.

PURPOSE: To analyze the metacarpophalangeal profile (MCPP) in individuals with Leri-Weill dyschondrosteosis (LWD) and to assess its value as a possible contributor to early diagnosis. MATERIAL AND METHODS: Hand profiles of 39 individuals with a diagnosis of LWD were calculated and analyzed. Discriminant analysis was applied to differentiate between LWD and normal individuals. RESULTS: There was a distinct pattern profile in LWD. Mean pattern profile showed two bone-shortening gradients, with increasing shortening from distal to proximal and from medial to lateral. Distal phalanx 2 was disproportionately long and second metacarpal was disproportionately short. Discriminant analysis yielded correct classification in 72% of analyzed cases. CONCLUSION: MCPP is not age-related and the analysis can be applied at any age, facilitating early diagnosis of LWD. In view of its availability, low costs, and diagnostic value, MCPP analysis should be considered as a routine method in the patients of short stature where LWD is suspected.

Validation of diagnostic imaging based on repeat examinations. An image interpretation model.

PURPOSE: To develop an interpretation model, based on repeatedly acquired images, aimed at improving assessments of technical efficacy and diagnostic accuracy in the detection of small lesions. MATERIAL AND METHODS: A theoretical model is proposed. The studied population consists of subjects that develop focal lesions which increase in size in organs of interest during the study period. The imaging modality produces images that can be re-interpreted with high precision, e.g. conventional radiography, computed tomography, and magnetic resonance imaging. At least four repeat examinations are carried out. RESULTS: The interpretation is performed in four or five steps: 1. Independent readers interpret the examinations chronologically without access to previous or subsequent films. 2. Lesions found on images at the last examination are included in the analysis, with interpretation in consensus. 3. By concurrent back-reading in consensus, the lesions are identified on previous images until they are so small that even in retrospect they are undetectable. The earliest examination at which included lesions appear is recorded, and the lesions are verified by their growth (imaging reference standard). Lesion size and other characteristics may be recorded. 4. Records made at step 1 are corrected to those of steps 2 and 3. False positives are recorded. 5. (Optional) Lesion type is confirmed by another diagnostic test. CONCLUSION: Applied on subjects with progressive disease, the proposed image interpretation model may improve assessments of technical efficacy and diagnostic accuracy in the detection of small focal lesions. The model may provide an accurate imaging reference standard as well as repeated detection rates and false-positive rates for tested imaging modalities. However, potential review bias necessitates a strict protocol.

Detection of small implanted tumors growing during repeated magnetic resonance imaging of the rabbit liver: application of an interpretation model.

PURPOSE: To apply experimentally and further develop a new image interpretation model based on repeated imaging and aimed at improving assessments of technical efficacy and diagnostic accuracy in the detection of small lesions. MATERIAL AND METHODS: VX2 carcinoma was implanted in the liver of 14 rabbits as two 1.1-1.7 mm3 cores. Magnetic resonance imaging was performed before and 4 days after implantation and then every second day up to the 14th to 20th day. One T2-weighted sequence (TSE T2) and three T1-weighted sequences (SE T1, GE T1, and TFL T1) were used. Interpretation was performed stepwise: three readers independently interpreted image sequences chronologically (step 1). Tumors were included at the last examination (step 2). By concurrent interpretation of repeated examinations, the earliest day at which tumors became visible and tumor size were recorded (step 3). Records were corrected (step 4) and autopsy was performed (step 5). Two procedures for use in calculating repeated detection rates of tumors with different magnetic resonance imaging sequences are presented and discussed. RESULTS: Of 40 macroscopic tumors, 34 were included. They were mainly small (size range SE T1: 1-3mm, TSE T2: 1.5-5 mm) when they became visible as determined at step 3, which was consistently earlier than observed at step 1. TSE T2, SE T1, and GE T1 did not differ significantly regarding earliest day of detection (step 3), while TFL T1 revealed the tumors later. The initial repeated detection rates were higher with TSE T2 than with the other sequences. Frequency of false positives varied over time, indicating fluctuating criteria for reporting tumors. CONCLUSION: A theoretical image interpretation model previously described proved to be applicable for detection of experimental liver tumors. The model was improved by introducing calculations of repeated detection rates for initial image interpretation using an imaging reference standard.

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.

Pulmonary gas exchange in cystic fibrosis: basal status and the effect of i.v. antibiotics and inhaled amiloride.

In order to evaluate the degree and type of gas exchange impairment in cystic fibrosis, ventilation/perfusion relationships in ten patients (mean age 26 yrs, mean Shwachman score 86) were examined. Pulmonary gas exchange was studied using the multiple inert gas elimination technique. High-resolution computed tomography (HRCT) and spirometry, including diffusing capacity, were performed after each gas exchange study for comparison. Examinations were done before and after home i.v. antibiotic treatment (HIVAT, 14 days) and after inhaled amiloride and placebo (14 days), in crossover fashion, clinical status after HIVAT serving as the baseline for the crossover study. Before HIVAT, the mean residual volume was 182% of the predicted value, the mean vital capacity 72% pred and the mean forced expiratory volume in one second 53% pred (p<0.001). The dispersion of pulmonary blood flow at different ventilation/perfusion ratios (V'/Q') ((logarithmic SD of the perfusion distribution (log SDQ)), used as an index for gas exchange impairment, was increased to a mean of 0.72. No linear correlation was seen between ventilation/perfusion inequality, spirometry and HRCT (p>0.05). After HIVAT, log SDQ was significantly improved to 0.66 (p<0.05). After placebo, but not after amiloride, log SDQ, arterial oxygen tension, alveolar-arterial oxygen tension difference and maximal expiratory flows when 50% and 25% of the forced vital capacity tension remain to be exhaled were significantly worse (p<0.05, respectively). Areas with a low V'/Q' were significantly lower after amiloride compared to after the placebo period (p<0.05). Moderate ventilation/perfusion inequality was present in the majority of the studied cystic fibrosis patients. The degree of ventilation/perfusion inequality cannot be estimated from spirometry or high-resolution computed tomography. The low proportion of low ventilation/perfusion ratios indicates that the regular treatment directed towards mucus plugging of small airways is beneficial. An improvement in the ventilation/perfusion relationship was seen after home i.v. antibiotic treatment and inhaled amiloride may possibly have a further positive effect on gas exchange.

Imaging of abdominal neuroblastoma in children.

PURPOSE: The aims of the study were: 1) to assess the efficacy of different imaging methods for use prior to treatment; 2) to compare the surgico-histopathologically-based International Neuroblastoma Staging System (INSS) staging with the imaging results; and 3) to suggest a localisation scheme for abdominal neuroblastoma. MATERIAL AND METHODS: Thirty-one children with an abdominal neuroblastoma (median age 2 years), underwent abdominal US, CT of chest and abdomen, MR imaging of abdomen and spine, chest radiography, skeletal survey, radionuclide bone scintigraphy, MIBG scintigraphy, and bone marrow biopsy. RESULTS: In the evaluation of local disease, CT and MR were superior to US. There was no significant difference between CT and MR in assessment of the location or size of the tumour. Evaluation of invasive growth and lymphadenopathy was uncertain irrespective of imaging modality. Intraspinal extension was more distinctly demonstrated with MR. Tissue characterization with CT and MR did not contribute in the assessment of the tumours. Contrast enhancement at CT and MR examinations both improved demarcation between tumour and kidney, and was a necessity for evaluation of vessel encasement with CT. The local disease was best assessed by either CT or MR, while metastatic disease was best revealed by CT, MR, scintigraphy or bone marrow biopsy. CONCLUSION: Imaging may be a valuable basis for clinical assessment and pretreatment staging of abdominal neuroblastoma.

Clinical value of imaging techniques in childhood osteomyelitis.

PURPOSE: The traditional approach to investigating suspected osteomyelitis in children includes conventional radiography and bone scintigraphy. The roles of US, CT and MR imaging are controversial. Our objective was to determine whether the additional use of these modalities would yield information likely to lead to treatment modification. MATERIAL AND METHODS: Sixty-five children with clinically suspected osteomyelitis took part in a prospective study. All patients underwent conventional radiography and bone scintigraphy. In addition to this, US, CT and MR imaging were all performed in 33 patients; the remaining 32 patients were examined with various combinations of these three modalities. The value of the additional information obtained was estimated retrospectively by a pediatric orthopedic surgeon in terms of possible modification of treatment. RESULTS: MR imaging was the modality with the highest sensitivity and specificity for detecting osteomyelitis. MR yielded information likely to influence treatment in the greatest proportion of patients (45%) followed by US (30%). CONCLUSION: The standard investigation protocol with the addition of US (because of its ability to detect subperiosteal abscesses early and simply) is adequate in uncomplicated cases. When additional imaging is required to outline a lesion, or in complicated cases, and when bone scintigraphy is inconclusive, MR imaging should also be performed. CT should be considered when MR investigation is not available or when anesthesia is required but cannot be provided.

MnDPDP enhancement in rabbit liver after intravenous bolus injection and slow infusion.

PURPOSE: To investigate the MR-enhancing effect of mangafodipir trisodium (MnDPDP, Teslascan) in the rabbit liver in relation to dose, mode of administration and imaging window. MATERIAL AND METHODS: MnDPDP was administered to 18 rabbits at a dose of 10 mumol/kg or 20 mumol/kg, as a bolus injection or infusion. MR imaging of the liver was performed at different time intervals. RESULTS: Peak liver enhancement was typically observed 10-30 min after administration and the enhancement declined with a half-time of about 5 h. This pattern was observed in all sequences (SE 400/15, FLASH, and SE 132/10), with both doses and with both rates of administration. The peak enhancement was greater, though not significantly so after 20 mumol/kg than after 10 mumol/kg. A higher relative peak signal was observed with SE 132/10 than with FLASH or SE 400/15. CONCLUSION: A good liver imaging result was obtained after a dose of 10 mumol/kg, either bolus or infusion, 10-30 min post-contrast with heavily T1-weighted sequences.

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.

Imaging and compartmental classification of solid pelvic tumours in children.

Thirty-five children aged from 1 day to 16 years (median 5 years) with solid pelvic tumours were investigated with US, CT and MR. All three methods gave similar estimates of tumour size. For defining location of the tumours, the pelvis was divided into three midline compartments (anterior, middle and posterior) and a right and left lateral compartment. CT and MR were accurate and equally reliable in determining the tumour location, US was less accurate. Evaluation of confinement to organ of origin was uncertain, regardless of imaging modality. Tissue characteristics with CT and MR did not contribute to the differentiation of the various tumour types, and contrast medium enhancement did not improve the discrimination. Compartmental localization was equally well assessed by CT and MR and, together with sex, was found to correlate with the tumour type.

Imaging of solid kidney tumours in children.

Eighteen children aged 6 months to 12 years with 20 solid renal tumours: 13 Wilms' tumours (WT), 2 clear cell sarcomas of the kidney, 1 malignant rhabdoid tumour of the kidney and 2 cases of bilateral nephroblastomatosis with Wilms' tumour underwent evaluation with US, CT and MR imaging. Contrast-enhanced CT and non-enhanced MR were equally accurate in determining the size and origin of the tumour but were unreliable in separation of stages I, II and III. US could only accurately assess the size of the tumours. MR characteristics varied somewhat between WTs and non-WTs but contrast-enhanced MR imaging might be useful for separation of WTs from nephroblastomatosis.

Renal biopsy in children: indications, technique and efficacy in 119 consecutive cases.

Consecutive renal biopsies were performed on native kidneys in 109 children and adolescents, aged 0.1-19.8 (mean 9.9) years (119 biopsies). Bleeding diatheses were excluded or treated pre-operatively with intravenous desmopressin acetate. Biopsies were performed by a radiologist under ultrasound imaging, using an automated spring-loaded device allowing selection of the length of the needle movement and score size. Diagnostically adequate tissue was retrieved in 118 of 119 (99.2%) biopsy procedures; 24-h post-biopsy ultrasonography disclosed a small haematoma of the biopsied kidney in 26% of the cases. No correlation was seen between the occurrence of haematoma and (treated) prolonged bleeding time or a decrease in the haemoglobin level. No major complications occurred. Newly developed macroscopic haematuria was reported by 7% and micturition pain by 7% of patients. Painful body movements were reported by 37%. We conclude that the use of ultrasound imaging and an automated gunshot technique is a safe and efficient method for performing renal biopsies in paediatric patients.