Painful paediatric hip: frog-leg lateral view only!

OBJECTIVE: For hip complaints in the paediatric population, it is common practice to acquire both anteroposterior (AP) and frog-leg lateral (FL) radiographs. This combination of views provides a high diagnostic yield, but also doubles radiation exposure. We investigated the diagnostic accuracy of obtaining a solitary FL view as compared to a combination of the AP and FL view. METHODS: Hip radiographs of 524 children (aged 2-15 years) referred for acute hip pain were retrospectively assessed by two independent radiologists. Cases of trauma, neuromuscular disorders or a history of known hip disease were excluded. Radiologists were blinded to the AP radiograph while assessing the solitary FL radiograph. We used Cohen's kappa test to calculate agreement between the assessment of both views and the solitary FL view. RESULTS: Agreement between the assessment of the solitary FL view and the combination of the AP and FL view was very high with a kappa value of 0.989. CONCLUSION: The diagnostic accuracy of the FL radiograph in cases of hip complaints in children is as high as the current standard employing both AP and FL views. Therefore a solitary FL radiograph appears sufficient. This practice would substantially reduce radiation exposure. KEY POINTS: • Radiation exposure in children should be kept to a minimum. • In paediatric hip radiography a solitary frog-leg lateral view suffices. • This reduces radiation exposure and costs of imaging.

Electronic collimation and radiation protection in paediatric digital radiography: revival of the silver lining.

In digital radiography we are now able to electronically collimate images after acquisition. This may seem convenient in paediatric imaging, but we have to be aware that electronic collimation has two major downsides. Electronic collimation implicates that the original field size should have been smaller and the child has been exposed to unnecessary radiation. Also, by use of electronic collimation, potentially important information may be lost. The "silver lining", denoting the X-ray beam collimation, can serve as a useful radiation protection instrument to check for proper field size and detect unnecessary exposure. Furthermore, the silver lining confirms all exposed anatomy is shown in the final image, and thus may also serve as a quality assurance instrument as the patient has the right to all acquired information. Teaching Points • The ability to electronically collimate an image after acquisition may serve to enhance contrast in the region of interest. • The ability to electronically collimate an image after acquisition carries the risk of overexposure. • The ability to electronically collimate an image after acquisition carries the risk of losing important information. • The silver lining can serve as a quality control instrument for proper collimation. • The patient has the right to all information obtained during an X-ray examination.

Increased echogenicity of renal cortex: a transient feature in acutely ill children.

OBJECTIVE: The purpose of our study was to determine the frequency of hyperechogenicity of renal parenchyma in children with acute abdominal illness and to evaluate the assumed transient feature of this hyperechogenicity. MATERIALS AND METHODS: Between January 2005 and February 2006, 189 consecutive patients (112 boys and 77 girls; mean age, 10 years) presenting with acute abdominal pain were examined with sonography. Patients with a known history of renal disease and those with acute urinary tract infection were excluded from the study. Echogenicity of the renal cortex in comparison with adjacent liver was recorded. Renal cortex echogenicity was divided into three groups; group 1, renal cortex echogenicity less than liver parenchyma echogenicity; group 2, renal cortex echogenicity similar to that of liver parenchyma; and group 3, renal cortex echogenicity greater than that of liver parenchyma. Patients with hyperechogenicity were reexamined with sonography after 2 weeks or more. The final sonographic diagnosis and clinical outcome were noted. RESULTS: Renal cortex echogenicity was equal to or greater than that of the liver parenchyma in 18% (n = 34) of 189 patients. Increased echogenicity of the renal cortex returned to normal in 2 or more weeks in all patients. Three patients had no follow-up. Clinical diagnoses were idiopathic acute abdominal pain (n = 74), appendicitis (n = 83), mesenteric lymphadenitis (n = 15), ileocecitis (n = 7), gastroenteritis (n = 7), Crohn's disease (n = 1), intussusception (n = 1), and pneumonia (n = 1). No concurrent renal disease was diagnosed. CONCLUSION: Increased echogenicity of renal parenchyma in children with acute illness is a transient feature and does not necessarily indicate renal disease.

Arterial infarction caused by carotid artery dissection in the neonate.

Arterial stroke in a neonate caused by carotid artery dissection is rare. We report two cases, one with dissection at the level of the skull base, one just distal to the carotid bulb. Non-invasive techniques like MR angiography and sonography demonstrated the dissection accurately. MR imaging, especially the diffusion-weighted images, showed the extension and site of the cerebral infarction. In one case dissection could be suspected following vacuum and forceps extraction. In the other no obvious birth trauma was reported. In conclusion, in a neonate with clinical signs suggestive of cerebral infarction, dissection of the carotid artery should be considered.

[Diagnostic surplus value of echography in children with acute abdominal pain]. / Diagnostische meerwaarde van echografie bij kinderen met acute buikklachten.

OBJECTIVE: To assess the role of echography in the diagnosis of acute abdominal symptoms in children. DESIGN: Prospective, descriptive. METHOD: During one year (1 June 1999-31 May 2000), abdominal ultrasonography was performed in all children with abdominal pain less than 2 weeks, who were referred to the emergency department of the Red Cross Hospital in The Hague (the Netherlands). An initial clinical diagnosis was made on the basis of the medical history, a physical examination and the results of laboratory tests. Subsequently, ultrasonography was performed by a radiologist who was unaware of the clinical diagnosis. A working hypothesis was reached on the basis of the clinical findings and the results of echography. The final diagnosis was made on the basis of either a histologic investigation after surgery or the condition at discharge. RESULTS: The study included 112 patients. The mean age was 9 years and 54% were boys. Acute appendicitis was ascertained in 48 children. The sensitivity of the clinical findings was 88% and the specificity 70%. The sensitivity of the clinical findings together with ultrasonography was 88% and the specificity 91%. The positive predictive value of the clinical findings alone was 69% and of the clinical findings together with ultrasonography 88%. CONCLUSION: Echography has added value in the diagnosis of acute abdominal pain in children; it increases the specificity of the physical examination. The number of negative laparotomies was decreased by the use of ultrasonography.

Neurologic dysfunction in patients with rheumatoid arthritis of the cervical spine. Predictive value of clinical, radiographic and MR imaging parameters.

The aim of this study was to evaluate if subjective symptoms, radiographic and especially MR parameters of cervical spine involvement, can predict neurologic dysfunction in patients with severe rheumatoid arthritis (RA). Sequential radiographs, MR imaging, and neurologic examination were performed yearly in 46 consecutive RA patients with symptoms indicative of cervical spine involvement. Radiographic parameters were erosions of the dens or intervertebral joints, disc-space narrowing, horizontal and vertical atlantoaxial subluxation, subluxations below C2, and the diameter of the spinal canal. The MR features evaluated were presence of dens and atlas erosion, brainstem compression, subarachnoid space encroachment, pannus around the dens, abnormal fat body caudal to the clivus, cervicomedullary angle, and distance of the dens to the line of McRae. Muscle weakness was associated with a tenfold increased risk of neurologic dysfunction. Radiographic parameters were not associated. On MR images atlas erosion and a decreased distance of the dens to the line of McRae showed a fivefold increased risk of neurologic dysfunction. Subarachnoid space encroachment was associated with a 12-fold increased risk. Rheumatoid arthritis patients with muscle weakness and subarachnoid space encroachment of the entire cervical spine have a highly increased risk of developing neurologic dysfunction.

Etiology of nephrocalcinosis in preterm neonates: association of nutritional intake and urinary parameters.

BACKGROUND: Nephrocalcinosis (NC) in preterm neonates has been described frequently, and small-scale studies suggest an unfavorable effect on renal function. The etiologic factors have not yet been fully clarified. We performed a prospective observational study to identify factors that influence the development of NC. METHODS: The study population consisted of 215 preterm neonates with a gestational age <32 weeks. Clinical characteristics and intake in the first four weeks of calcium, phosphorus, vitamin D, protein, and ascorbic acid were noted. Serum calcium, phosphate, vitamin D, magnesium, uric acid, creatinine, urea and urinary calcium, phosphate, oxalate, citrate, magnesium, uric acid, and creatinine were assessed at four weeks of age and at term. Renal ultrasonography (US) was performed at four weeks and at term. At term was defined as a postconceptional age of 38 to 42 weeks. RESULTS: NC was diagnosed by means of US in 33% at four weeks and in 41% at term. Patients with NC at four weeks had a significantly higher mean intake of calcium (P < 0.05), phosphorus (P < 0.05), and ascorbic acid (P < 0.01) than patients without NC. They had a higher mean serum calcium (2.55 vs. 2.46 mmol/L, P < 0.01) and a higher mean urinary calcium/creatinine ratio (2.6 vs. 2.1 mmol/mmol, P < 0.05). Patients with NC at term had a lower birth weight (1142 vs. 1260 g, P < 0.05) and a lower gestational age (28.8 vs. 29.4 weeks, P < 0.05), were treated significantly longer with furosemide, dexamethasone, theophylline, and thiazides, developed chronic lung disease more frequently (40 vs. 16%, P < 0.001), and had a higher mean urinary calcium/creatinine ratio (2.7 vs. 2.3 mmol/mmol, P < 0.05) and a lower mean urinary citrate/calcium ratio (1.1 vs. 1.7 mmol/mmol, P = 0.005). CONCLUSIONS: NC develops as a result of an imbalance between stone-inhibiting and stone-promoting factors. A high intake of calcium, phosphorus, and ascorbic acid, a low urinary citrate/calcium ratio, a high urinary calcium/creatinine ratio, immaturity, and medication to prevent or treat chronic lung disease with hypercalciuric side effects appear to contribute to the high incidence of NC in preterm neonates.

Ultrasonographic features of nephrocalcinosis in preterm neonates.

Nephrocalcinosis (NC) in preterm neonates has been reported frequently and small studies suggest an unfavourable effect on renal function. Data on ultrasonic features are limited and the reproducibility of ultrasonography (US) in detecting NC in preterm neonates is unknown. In this study, interobserver and intraobserver agreement of US was determined through videotape recordings of US examinations of preterm neonates. Furthermore, a prospective US study was performed in 215 preterm neonates (gestational age < 32 weeks) to evaluate ultrasonic characteristics, incidence, time course and effect on kidney length of NC. Patients were studied at 4 weeks after birth and at term. Patients with NC were followed for 2 years. NC was defined as bright reflections in the medulla or cortex seen in both transverse and longitudinal direction. The length of the kidneys was noted. The kappa value was 0.84 for intraobserver and 0.46 for interobserver agreement, whereas the overall agreement was 73%. NC was found in 50 of 150 (33%) patients at 4 weeks and in 83 of 201 patients (41%) at term. NC was localized mainly in the medulla. At 1 and 2 years, NC had persisted in 36% and 26%, respectively, of the patients with NC at term. Kidney length was comparable with normal values. In conclusion, US has a very good intraobserver agreement but a moderate interobserver agreement in detecting NC. Medullary NC is common among preterm neonates. During the first 2 years of life, the incidence decreases spontaneously and NC does not influence kidney length.

Radiation burden to paediatric patients due to micturating cystourethrography examinations in a Dutch children's hospital.

Micturating cystourethrography (MCU) examinations of paediatric patients in a major Dutch children's hospital (JKZ) were evaluated to generate quantitative information on effective dose (E). A standard examination involves three radiographs plus fluoroscopy. Observed total dose-area product (DAP) for 84 children increased, on average, with increasing age class from 0.2 to 2.2 Gy cm2. In 11 cases, separate DAP per view was measured; enabling determination, per view, of organ (CF) and effective (CE) dose conversion factors, i.e. dose per unit of DAP. Monte Carlo simulation of photon transport in male and female mathematical phantoms was applied for newborn, 1 year, 5 year, 10 year and 15-year-old patients, and interpolated for other ages. CE per view decreases with increasing age class, yielding about a factor of 10 difference between the extremes of the range. Female values are usually some 20-30% above male ones. CE for one of the views appeared to be representative for the complete examination and was used to estimate total E for each patient. Averaged per age class, E remains approximately constant at 0.3-0.4 mSv, although a tendency to increase with increasing age exists, for females in particular. Within an age class, individual patients may differ in E by a factor of two up to six. Stomach, lower large intestine, bladder wall, liver and ovaries receive relatively high doses. Compared with published data and DAP measured in a few other Dutch hospitals, the radiation burden of MCU is low at the JKZ. This indicates a good degree of optimization with respect to radiation protection (e.g. modern equipment, increased tube voltage, fast film-screen combination).

The cervical spine in rheumatoid arthritis: relationship between neurologic signs and morphology of MR imaging and radiographs.

OBJECTIVE: Comparison of clinically observed neurologic long tract signs in a heterogeneous group of patients with rheumatoid arthritis (RA), with morphologic abnormalities of the cervical spine as depicted on radiographs and magnetic resonance (MR) images. DESIGN: The patients were prospectively assigned to one of three classes on the basis of their neurologic status. Lateral cervical spine radiographs and sagittal T1-weighted and gradient echo images were performed. The qualitative MR features evaluated were erosion of the dens and atlas, brain stem compression, subarachnoid space encroachment, pannus around the dens, appearance of the fat body caudal to the clivus, and the signal intensity of the pannus. The quantitative imaging parameters were the cervicomedullary angle and the distance of the dens to the line of McRae. PATIENTS: Sixty-three consecutive patients with RA and subjective symptoms, especially neck or occipital pain, and/or clinical objective signs consistent with a compromised cervical cord were included in this study. RESULTS AND CONCLUSIONS: Damage documented with radiographs and MR imaging in patients with RA is often severe, even in those without neurologic signs (class 1). None of the abnormalities confined to the atlantoaxial level correlated significantly with neurologic classification. Subarachnoid space encroachment anywhere in the entire cervical spine did correlate significantly with neurologic classification.

Can conventional radiographs be used to monitor the effect of neoadjuvant chemotherapy in patients with osteogenic sarcoma?

OBJECTIVE: The objective of this study was to assess the effectiveness of conventional radiography in predicting histopathologic response in patients with osteogenic sarcoma who were treated with preoperative chemotherapy. DESIGN AND PATIENTS: The radiographs of 22 patients with an osteogenic sarcoma, taken before and after neoadjuvant chemotherapy, were reviewed. Tumour location, size, radiographic appearance, margination, cortical destruction and periosteal reaction were evaluated. The findings were correlated with the histopathologic response of the surgical specimen. RESULTS: None of the findings proved to be of predictive value for the histopathologic response. Increase in tumour diameter and increase in ossification and/or calcification, which were seen in more than half of the patients, did not correlate with response. CONCLUSION: Conventional radiographs do not contribute to the identification of good or poor responders.

Can MRI predict the histopathological response in patients with osteosarcoma after the first cycle of chemotherapy?

The magnetic resonance (MR) changes after one cycle of chemotherapy were compared with the prechemotherapy studies in 39 patients with osteosarcoma, in order to identify MR changes which can be used to assess early response to chemotherapy. Measurements of total tumour volume, signal intensity, and tumour enhancement of the intra- and extraosseous tumour component were performed. Change in the amount of oedema was subjectively assessed. Changes observed were correlated with histopathological response. Changes in tumour volume and of the signal intensity of the extraosseous tumour component on T2-weighting were the only two parameters which correlated significantly (P < 0.05) with histopathological response. Increase of tumour volume is the most significant parameter and indicates poor response (sensitivity 89%, specificity 73%). Only one good responder showed increase of tumour volume. Decreased or stable tumour volume was observed in both good and poor responders. Increase of signal intensity was found exclusively in five poor responders (sensitivity 100%, specificity 23%). Decreased or stable signal intensity was observed in both good and poor responders. Changes in the amount of oedema and contrast enhancement could not predict response at an early stage. We conclude that increase of tumour volume and increase of T2 signal intensity of extraosseous tumour can be predictive for poor response. MR criteria are not helpful in the early identification of good responders.

Monitoring the effect of chemotherapy in Ewing's sarcoma of bone with MR imaging.

Magnetic resonance (MR) imaging was performed in 26 patients with Ewing's sarcoma of bone preceding and following neoadjuvant chemotherapy, to assess tumour response non-invasively prior to surgery. T1- and T2-weighted spin echo images were obtained. Changes including intra- and extramedullary signal intensities, tumour demarcation, tumour volume and the appearance of residual extramedullary tumour were compared with histopathology of the resected specimens. Reduction of tumour volume was significantly higher in good responders. Other single parameters did not correlate with histologic tumour response. However, when several MR parameters summarized in a classification system were combined, a positive correlation with histopathologic response was found. A limited decrease of tumour volume (< 25%) and/or residual soft tissue mass following chemotherapy correlated with a poor response. An inhomogeneous, well-defined cuff of abnormal tissue encircling the bone and/or radiological disappearance of the soft tissue tumour component following chemotherapy correlated with good response. Twenty-three out of 26 patients were correctly classified by MR as good or poor responders. Minimal residual disease (< 10% of the entire tumour volume), observed histologically, could not be identified with MR imaging. Tumour volume reduction and residual extramedullary tumour, rather than changes of signal intensity, are major features for evaluating the response to chemotherapy in Ewing's sarcoma.

MR imaging of edema accompanying benign and malignant bone tumors.

To evaluate the incidence, quantity, and presentation of intra- and extraosseous edema accompanying benign and malignant primary bone lesions, the magnetic resonance (MR) studies of 63 consecutive patients with histologically proven primary bone tumors were reviewed. MR scans were assessed for the presence and quantity of marrow and soft tissue edema and correlated with peroperative findings, resected specimens and follow-up data. The signal intensity and enhancement of tumor and edema prior to and after intravenous administration (if any) of gadolinium-labeled diethylene triamine pentaacetate (Gd-DTPA) was analyzed. Marrow edema was encountered adjacent to 8 of 39 malignant tumors and 14 of 24 benign lesions. Soft tissue edema was found accompanying 28 of 39 malignancies and 10 of 24 benign disorders. On unenhanced T1-weighted MR images tumor and edema were difficult to differentiate. Tumor inhomogeneity made this differentiation easier on T2-weighted sequences. In 36 patients the contrast medium Gd-DTPA was used. Edema was present in 27 of these patients and the respective enhancement of tumor and edema could be compared. Edema always enhanced homogeneously, and in most cases it enhanced to a similar degree as or more than tumor. Marrow and, more specifically, soft tissue edema is a frequent finding adjacent to primary bone tumors. The mere presence and quantity of marrow and soft tissue edema are unreliable indicators of the biologic potential of a lesion. Unenhanced MR scans cannot always differentiate between tumor and edema, but the administration of Gd-DTPA is of assistance in differentiating tumor from edema.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in tumor perfusion induced by chemotherapy in bone sarcomas: color Doppler flow imaging compared with contrast-enhanced MR imaging and three-phase bone scintigraphy.

PURPOSE: To prospectively evaluate color Doppler flow imaging (CDFI) with spectral analysis versus dynamic gadolinium-enhanced magnetic resonance (MR) imaging and three-phase bone scintigraphy in monitoring the effect of chemotherapy on bone sarcomas. MATERIALS AND METHODS: Seventeen osteosarcomas and five Ewing sarcomas were examined with these imaging techniques before and after chemotherapy. Results were compared with the histopathologic response. RESULTS: Before chemotherapy, high systolic Doppler frequency shifts (DFSs) and/or low-impedance Doppler signals were found in all but one tumor. Resistive indexes (RIs) in tumor-feeding arteries were substantially lower than in contralateral normal arteries. After chemotherapy, DFSs disappeared in five of seven good respondents and remained substantial in all but one poor respondent. RIs increased substantially in all good respondents and decreased or showed minor changes only in all but one poor respondent. CONCLUSION: CDFI with spectral analysis has an advantage over the other two techniques in monitoring the efficacy of chemotherapy in bone sarcomas because of its superior accuracy, noninvasive nature, availability, and low cost.

Magnetic resonance relaxation times of normal tissue in the course of chemotherapy: a study in patients with bone sarcoma.

To study the effect of chemotherapy on normal fat, skeletal muscle, and bone marrow, T1 and T2 relaxation times were measured in 15 patients with bone sarcoma before and after each cycle of preoperative chemotherapy. A section plane containing the tumor and if possible the nonaffected extremity was imaged with combined multiecho spin echo and inversion recovery pulse sequences. T1 and T2 relaxation times were calculated in the normal-appearing tissues. Although some variation was found in the values in the individual patient and between patients, no systematic changes of relaxation times of fat, muscle, or bone marrow occurred in the course of treatment. We conclude that the chemotherapy used in bone sarcoma has no effect on relaxation times of normal fat, muscle, and bone marrow, and that therefore these tissues may serve as a reference for the signal intensity of tumor.

Osteosarcoma: chemotherapy-induced changes at MR imaging.

Fifty-seven patients undergoing chemotherapy for osteosarcoma underwent evaluation with magnetic resonance (MR) imaging to identify changes related to a good or poor response. Spin-echo MR images obtained after preoperative chemotherapy were compared with images obtained before treatment. Histopathologic examination of each resected specimen was used to quantify the response. An increase in tumor volume and increased or unchanged edema were predictive of a poor histopathologic response (predictive values, 85%-92%). Decreased or unchanged tumor volume and a decrease in edema were poor predictors of a good response (predictive values, 56%-62%). Improved tumor demarcation, an increase in the size of areas of low signal intensity, and a decrease in joint effusion occurred independently of histopathologic response in almost half of the patients. With a subjective interpretation of MR images, poor respondents can be identified if an increase in tumor volume or no decrease in the amount of edema is seen. Subjective criteria do not contribute to the identification of good respondents.

The value of MR imaging in monitoring the effect of chemotherapy on bone sarcomas.

We studied the value of MR imaging in monitoring the response of Ewing sarcoma and osteosarcoma to chemotherapy. Relative signal-intensity changes on MR images in the course of chemotherapy were compared with changes in tumor volume and histopathologic findings. MR scans (T1- and T2-weighted spin-echo images) were obtained in 20 patients with bone sarcoma. The first MR scan was obtained before the administration of chemotherapy in all patients. The follow-up scan was obtained in the course of treatment, before surgery. Tumor-volume and signal-intensity measurements of the intra- and extraosseous components of the tumor were analyzed. In 17 patients, histopathologic findings of the resected tumor were available for comparison with the MR images. In 12 of 17 patients there was complete agreement between changes in tumor volume, changes in the signal intensity of the extraosseous tumor component on T2-weighted images, and histopathology. In another four cases, changes in signal intensity correlated either with histopathology or with changes in tumor volume. In one patient with a pathologic fracture, no such correlation existed. A significant correlation was found between changes in signal intensities and pathologic response (r = .57, p = .02), as well as between changes in tumor volume and pathologic response (r = .53, p = .03). No correlation could be found between changes in signal intensity of the intraosseous tumor component and changes in tumor volume or histopathology. We conclude that the signal intensity of the extraosseous component of bone sarcomas on T2-weighted MR images in addition to changes in tumor volume may be useful in evaluating response to chemotherapy.