Cross-validation of ultrasound imaging in adolescent idiopathic scoliosis.

PURPOSE: Adolescent idiopathic scoliosis (AIS) patients are exposed to 9-10 times more radiation and a fivefold increased lifetime cancer risk. Radiation-free imaging alternatives are needed. Ultrasound imaging of spinal curvature was shown to be accurate, however, systematically underestimating the Cobb angle. The purpose of this study is to create and cross-validate an equation that calculates the expected Cobb angle using ultrasound spinal measurements of AIS patients. METHODS: Seventy AIS patients with upright radiography and spinal ultrasound were split randomly in a 4:1 ratio to the equation creation (n = 54) or validation (n = 16) group. Ultrasound angles based on the spinous processes shadows were measured automatically by the ultrasound system (Scolioscan, Telefield, Hong Kong). For thoracic and lumbar curves separately, the equation: expected Cobb angle = regression coefficient × ultrasound angle, was created and subsequently cross-validated in the validation group. RESULTS: Linear regression analysis between ultrasound angles and radiographic Cobb angles (thoracic: R2 = 0.968, lumbar: R2 = 0.923, p < 0.001) in the creation group resulted in the equations: thoracic Cobb angle = 1.43 × ultrasound angle and lumbar Cobb angle = 1.23 × ultrasound angle. With these equations, expected Cobb angles in the validation group were calculated and showed an excellent correlation with the radiographic Cobb angles (thoracic: R2 = 0.959, lumbar: R2 = 0.936, p < 0.001). The mean absolute differences were 6.5°-7.3°. Bland-Altman plots showed good accuracy and no proportional bias. CONCLUSION: The equations from ultrasound measurements to Cobb angles were valid and accurate. This supports the implementation of ultrasound imaging, possibly leading to less frequent radiography and reducing ionizing radiation in AIS patients.

Scoring haemophilic arthropathy on X-rays: improving inter- and intra-observer reliability and agreement using a consensus atlas.

OBJECTIVES: The radiological Pettersson score (PS) is widely applied for classification of arthropathy to evaluate costly haemophilia treatment. This study aims to assess and improve inter- and intra-observer reliability and agreement of the PS. METHODS: Two series of X-rays (bilateral elbows, knees, and ankles) of 10 haemophilia patients (120 joints) with haemophilic arthropathy were scored by three observers according to the PS (maximum score 13/joint). Subsequently, (dis-)agreement in scoring was discussed until consensus. Example images were collected in an atlas. Thereafter, second series of 120 joints were scored using the atlas. One observer rescored the second series after three months. Reliability was assessed by intraclass correlation coefficients (ICC), agreement by limits of agreement (LoA). RESULTS: Median Pettersson score at joint level (PSjoint) of affected joints was 6 (interquartile range 3-9). Using the consensus atlas, inter-observer reliability of the PSjoint improved significantly from 0.94 (95 % confidence interval (CI) 0.91-0.96) to 0.97 (CI 0.96-0.98). LoA improved from ±1.7 to ±1.1 for the PSjoint. Therefore, true differences in arthropathy were differences in the PSjoint of >2 points. Intra-observer reliability of the PSjoint was 0.98 (CI 0.97-0.98), intra-observer LoA were ±0.9 points. CONCLUSIONS: Reliability and agreement of the PS improved by using a consensus atlas. KEY POINTS: • Reliability of the Pettersson score significantly improved using the consensus atlas. • The presented consensus atlas improved the agreement among observers. • The consensus atlas could be recommended to obtain a reproducible Pettersson score.

Computed Tomography Observer Agreement in Staging Malignant Lymphoma.

OBJECTIVE: To determine pretreatment computed tomography observer agreement in patients with newly diagnosed lymphoma. METHODS: Forty-nine computed tomography scans were reviewed by 3 experienced radiologists, with each scan assessed twice by 1 observer. Predefined nodal and extranodal regions were assessed, and Ann Arbor stages were assigned. K-statistics were defined as poor (κ < 0.2), fair (κ > 0.2 to κ ≤ 0.4), moderate (κ > 0.4 to κ ≤ 0.6), substantial (κ > 0.6 to κ ≤ 0.8), and almost perfect (κ > 0.8 to κ ≤ 1). RESULTS: Nodal interobserver agreement varied from 0.09 for infraclavicular involvement to 0.95 for para-iliac involvement; intraobserver agreement was substantial to almost perfect, except for infraclavicular nodes. Extranodal interobserver agreement varied from 0.56 to 0.88; intraobserver agreement was substantial to almost perfect. Ann Arbor stage interobserver agreement varied from 0.57 to 0.69; intraobserver agreement was substantial. CONCLUSION: Computed tomography observer agreement in staging malignant lymphoma appears to be suboptimal.

Whole-body MRI-DWI for assessment of residual disease after completion of therapy in lymphoma: A prospective multicenter study.

BACKGROUND: To assess the performance of whole-body MRI including diffusion-weighted imaging (whole-body MRI-DWI) for the detection of residual disease after completion of treatment in lymphoma patients. METHODS: Twenty-six patients with lymphoma prospectively underwent whole-body MRI-DWI (1.5 Tesla MR) and 18F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET)/computed tomography (CT) for posttreatment evaluation which were visually assessed. Apparent diffusion coefficient (ADC) and FDG-PET/CT standardized uptake value measurements were performed in all residual lesions. An unblinded expert panel reviewed all cases and determined the presence or absence of posttreatment residual disease using all available imaging (except for whole-body MRI-DWI), clinical, and histopathological information with a follow-up of at least 6 months. The performance of whole-body MRI-DWI was compared with this panel reference standard. RESULTS: Five of 26 patients were diagnosed with residual disease. Sensitivity and specificity for detection of residual disease with whole-body MRI-DWI were 100% and 62%, respectively. By ROC analysis, the optimal threshold of ADC was 1.21 × 10(-3) mm(2) /s with sensitivity and specificity of 100% and 91.7%, respectively. CONCLUSION: Our initial results suggest that visual whole-body MRI-DWI analysis has a very good sensitivity for detecting viable residual lesions after completion of therapy but lacks specificity. ADC measurements could potentially increase the specificity of whole-body MRI.

Diagnostic accuracy of Tc-99m DMSA scintigraphy and renal ultrasonography for detecting renal scarring and relative function in patients with spinal dysraphism.

AIMS: To study additional benefits of performing Tc-99m dimercaptosuccinic acid (Tc-99m-DMSA) scintigraphy as part of the follow-up of adults with spinal dysraphism (SD), compared with ultrasonography, with regard to finding renal scarring and difference in split renal function. METHODS: Between January 2011 and April 2013 every patient visiting our specialized outpatient clinic for adults with SD was invited to undergo both renal ultrasonography and Tc-99m-DMSA scintigraphy. Outcomes of both modalities were compared, with focus on renal scarring. The relation between renal scarring and hypertension was also assessed. RESULTS: In total, 122 patients (with 242 renal units) underwent both renal scintigraphy and ultrasonography. More scars were seen on DMSA scintigraphy than on ultrasonography: 45.9% vs. 10.3% of renal units; P < 0.001. Renal scarring seen on DMSA was associated with the presence of hypertension (P = 0.049) whereas scarring seen on ultrasonography was not (P = 0.10). If ultrasonography was difficult to interpret, many more scars were missed on ultrasonography (78.9%) compared with easily interpretable ultrasonographic images (30.6%; P < 0.001). CONCLUSIONS: In adults with SD, ultrasonography is of value to diagnose dilatation and stones of the upper urinary tract; however, compared with DMSA renography, renal scars are often missed, especially when the ultrasound is difficult to interpret.

Whole-body MRI, including diffusion-weighted imaging, for staging lymphoma: comparison with CT in a prospective multicenter study.

PURPOSE: To compare whole-body magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI), to computed tomography (CT) for staging newly diagnosed lymphoma. MATERIALS AND METHODS: In all, 108 patients with newly diagnosed lymphoma prospectively underwent whole-body MRI (T1-weighted and T2-weighted short inversion time inversion recovery [n = 108], and DWI [n = 104]) and CT. Ann Arbor stages were assigned according to whole-body MRI and CT findings. Staging disagreements were resolved using bone marrow biopsy, FDG-PET, and follow-up studies. The results were descriptively analyzed. RESULTS: Staging results of whole-body MRI without DWI were equal to those of CT in 66.6%, higher in 24.1%, and lower in 9.3%, with correct/incorrect/unresolved higher staging and incorrect/unresolved lower staging relative to CT in 15/7/4 and 9/1 patient(s), respectively. Staging results of whole-body MRI with DWI were equal to those of CT in 65.4%, higher in 27.9%, and lower in 6.7%, with correct/incorrect/unresolved higher staging and incorrect/unresolved lower staging relative to CT in 18/6/5 and 6/1 patient(s), respectively. CONCLUSION: The results of this study suggest that whole-body MRI staging equals CT staging in the majority of patients with newly diagnosed lymphoma. No advantage of additional DWI was demonstrated. Whole-body MRI can be a good alternative to CT if radiation exposure should be avoided.

Whole-body MRI for initial staging of paediatric lymphoma: prospective comparison to an FDG-PET/CT-based reference standard.

OBJECTIVE: To compare whole-body MRI, including diffusion-weighted imaging (whole-body MRI-DWI), with FDG-PET/CT for staging newly diagnosed paediatric lymphoma. METHODS: A total of 36 children with newly diagnosed lymphoma prospectively underwent both whole-body MRI-DWI and FDG-PET/CT. Whole-body MRI-DWI was successfully performed in 33 patients (mean age 13.9 years). Whole-body MRI-DWI was independently evaluated by two blinded observers. After consensus reading, an unblinded expert panel evaluated the discrepant findings between whole-body MRI-DWI and FDG-PET/CT and used bone marrow biopsy, other imaging data and clinical information to derive an FDG-PET/CT-based reference standard. RESULTS: Interobserver agreement of whole-body MRI-DWI was good [all nodal sites together (κ = 0.79); all extranodal sites together (κ = 0.69)]. There was very good agreement between the consensus whole-body MRI-DWI- and FDG-PET/CT-based reference standard for nodal (κ = 0.91) and extranodal (κ = 0.94) staging. The sensitivity and specificity of consensus whole-body MRI-DWI were 93 % and 98 % for nodal staging and 89 % and 100 % for extranodal staging, respectively. Following removal of MRI reader errors, the disease stage according to whole-body MRI-DWI agreed with the reference standard in 28 of 33 patients. CONCLUSIONS: Our results indicate that whole-body MRI-DWI is feasible for staging paediatric lymphoma and could potentially serve as a good radiation-free alternative to FDG-PET/CT. KEYPOINTS: • Accurate staging is important for treatment planning and assessing prognosis • Whole-body MRI-DWI could be a good radiation-free alternative to FDG-PET/CT • Interobserver agreement of whole-body MRI-DWI is good • Agreement between whole-body MRI and the FDG-PET/CT reference standard is good • Most discrepancies were caused by suboptimal accuracy of size measurements on MRI.

Can full-dose contrast-enhanced CT be omitted from an FDG-PET/CT staging examination in newly diagnosed FDG-avid lymphoma?

OBJECTIVE: To determine whether full-dose contrast-enhanced computed tomography (CT) (CECT) can be omitted from an F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) (FDG-PET)/CT staging examination in newly diagnosed FDG-avid lymphoma. METHODS: Twenty-nine patients with newly diagnosed FDG-avid lymphoma prospectively underwent unenhanced low-dose FDG-PET/CT and CECT. Different observers evaluated unenhanced low-dose FDG-PET/CT and CECT in a blinded manner. Ann Arbor stages according to unenhanced low-dose FDG-PET/CT and CECT were compared, and discrepancies between the 2 imaging modalities were resolved using bone marrow biopsy and posttreatment FDG-PET/CT as reference standard. Finally, it was assessed as to how many cases therapy would have been changed based on additional CECT findings. RESULTS: In 27 of 29 patients (93%; 95% confidence interval, 78%-98%), CECT either did not change or did not correctly change the Ann Arbor stage that was assigned according to unenhanced low-dose FDG-PET findings. In 2 of 29 patients (7%; 95% confidence interval, 2%-22%), CECT correctly provided another Ann Arbor stage than unenhanced low-dose FDG-PET/CT. In the latter 2 cases, therapy would not have been changed based on additional CECT findings. CONCLUSIONS: Unenhanced low-dose FDG-PET/CT alone is suggested as the primary imaging modality of choice for staging patients with newly diagnosed FDG-avid lymphoma. This diagnostic approach is particularly indicated in younger patients in whom diagnostic radiation exposure should be minimized and in patients who are at increased risk of CT contrast-induced allergic reactions or nephropathy.

Transinguinal sonographic determination of the position of the femoral head after reposition and follow-up in a spica cast.

BACKGROUND: Transinguinal sonography can be used to demonstrate the position of the femoral head after reduction of a dislocated hip. OBJECTIVE: To determine whether transinguinal sonography can replace radiography and CT in the follow-up after reduction of a hip dislocation? MATERIALS AND METHODS: Thirty-three children with 39 dislocated hips were followed up with sonography after reduction and immobilization in a spica cast. In cases of an abnormal position a CT scan was advised. A pelvic radiograph at the end of treatment served as an indicator that no dislocations were missed during the previous sonographic examinations. RESULTS: The repositioned hips were examined on 138 occasions. Twenty-four examinations were abnormal and CT scanning was performed on 11 occasions. In four children additional CT was done because a recurrent dislocation was suspected or because sonography was difficult to perform. No dislocations were demonstrated. In five children a recurrent dislocation was suspected, on one or more occasions. In all but one child a CT scan was performed that confirmed the dislocation. CONCLUSION: Transinguinal sonography is well-suited to demonstrate a normal position of the femoral head in a spica cast. Transinguinal sonography decreases the number of radiographs and CT scans and reduces the exposure to ionizing radiation.

Evaluation of a training program for general ultrasound screening for developmental dysplasia of the hip in preventive child health care.

BACKGROUND: A research study in the Netherlands showed that general ultrasound (US) screening was cost-effective in the detection of developmental dysplasia of the hip (DDH). This study was followed by a pilot implementation study. Part of this pilot implementation study is to investigate whether professionals of the infant health care (IHC) system, with no previous US experience, would be able to perform US of the hip. OBJECTIVE: This study looks at health care worker ability to classify US images into a modified Graf system. MATERIALS AND METHODS: After theoretical and practical training, seven nurses and physicians of the participating IHC centers reported their findings on sonographic images of 80 children. This was repeated five months later. From the two evaluation moments the intraobserver agreement and the interobserver agreement was determined. RESULTS: The average estimated interobserver Cohen's kappa for both sessions was for nurses 0.6 and for physicians 0.5. The second evaluation showed a decrease from an average of 4.3% missed cases per screener to 2.3% and an increase of an average of 5% false positives per screener to 9.1%. CONCLUSION: The inter- and intra-observer agreement is comparable to similar studies in which the participants had a professional background in US examination. The level of agreement of the trainees in the perspective of the screening process was considered sufficient for the pilot implementation project.

Stent placement in patients with atherosclerotic renal artery stenosis and impaired renal function: a randomized trial.

BACKGROUND: Little is known about the efficacy and safety of renal artery stenting in patients with atherosclerotic renal artery stenosis (ARAS) and impaired renal function. OBJECTIVE: To determine the efficacy and safety of stent placement in patients with ARAS and impaired renal function. DESIGN: Randomized clinical trial. Randomization was centralized and computer generated, and allocation was assigned by e-mail. Patients, providers, and persons who assessed outcomes were not blinded to treatment assignment. SETTING: 10 European medical centers. PARTICIPANTS: 140 patients with creatinine clearance less than 80 mL/min per 1.73 m(2) and ARAS of 50% or greater. INTERVENTION: Stent placement and medical treatment (64 patients) or medical treatment only (76 patients). Medical treatment consisted of antihypertensive treatment, a statin, and aspirin. MEASUREMENTS: The primary end point was a 20% or greater decrease in creatinine clearance. Secondary end points included safety and cardiovascular morbidity and mortality. RESULTS: Forty-six of 64 patients assigned to stent placement had the procedure. Ten of the 64 patients (16%) in the stent placement group and 16 patients (22%) in the medication group reached the primary end point (hazard ratio, 0.73 [95% CI, 0.33 to 1.61]). Serious complications occurred in the stent group, including 2 procedure-related deaths (3%), 1 late death secondary to an infected hematoma, and 1 patient who required dialysis secondary to cholesterol embolism. The groups did not differ for other secondary end points. LIMITATION: Many patients were falsely identified as having renal artery stenosis greater than 50% by noninvasive imaging and did not ultimately require stenting. CONCLUSION: Stent placement with medical treatment had no clear effect on progression of impaired renal function but led to a small number of significant procedure-related complications. The study findings favor a conservative approach to patients with ARAS, focused on cardiovascular risk factor management and avoiding stenting.

MRI predicts 5-year joint bleeding and development of arthropathy on radiographs in hemophilia.

Magnetic resonance imaging (MRI) is considered as the reference standard to assess early joint changes in hemophilia. However, the clinical relevance of MRI findings is still unknown. The aim of this prospective study was to assess the predictive value of MRI for 5-year joint bleeding and progression of arthropathy in patients with hemophilia. Both knees and ankles of patients with hemophilia and absent or limited arthropathy on radiographs were assessed by using MRI and radiographs. MRI scans were scored according to the International Prophylaxis Study Group MRI score for hemophilic arthropathy. Patients were followed up for 5 years, including assessment of joint bleeding and repeated radiographic assessment. Associations between baseline MRI findings with 5-year bleeding and progression of arthropathy were expressed as odds ratios (OR), adjusted for severity of disease and joint bleeding history. Baseline assessment included 104 joints of 26 patients with hemophilia (median age, 21 years). Four ankles with severe joint changes were excluded. Follow-up was available for 96 (92%) of 104 joints. During 5 years of follow-up, bleeding was reported for 36% of joints. Five-year bleeding was significantly increased in joints with synovial hypertrophy at 80% vs 27% in joints without synovial hypertrophy (OR, 10.1; 95% confidence interval, 3.4-31.3). In joints with normal baseline radiographs, any osteochondral or synovial changes on MRI were associated with radiographic changes 5 years later (positive predictive value, 75%; negative predictive value, 98%). Joints with synovial hypertrophy on MRI had a significantly higher chance of 5-year bleeding. All MRI changes, except effusion, were strong predictors for development of arthropathy on radiographs.

A reliability and validity study for different coronal angles using ultrasound imaging in adolescent idiopathic scoliosis.

BACKGROUND CONTEXT: Radiation exposure remains a big concern in adolescent idiopathic scoliosis (AIS). Ultrasound imaging of the spine could significantly reduce or possibly even eliminate this radiation hazard. The spinous processes (SPs) and transverse processes (TPs) were used to measure the coronal deformity. Both landmarks provided reliable information on the severity of the curve as related to the traditional Cobb angle. However, it remained unclear which coronal ultrasound angle is the most appropriate method to measure the curve severity. PURPOSE: The objective of this study was to test the reliability and the validity of several ultrasound angle measurements in the coronal plane as compared with the radiographic coronal Cobb angle in patients with AIS. STUDY DESIGN/SETTING: This is a cross-sectional study. PATIENT SAMPLE: The study included 33 patients with AIS, both male and female (Cobb angle range: 3°-90°, primary and secondary curves), who underwent posterior-anterior radiography of the spine. OUTCOME MEASURES: The outcome measures were the reliability (intraclass correlation coefficients [ICCs] for the intra- and interobserver variabilities) and the validity (linear regression analysis and Bland-Altman method, including the mean absolute difference [MAD]) of different ultrasound measurements. MATERIALS AND METHODS: The patients were scanned using a dedicated ultrasound machine (Scolioscan, Telefield Medical Imaging Ltd, Hong Kong). The reliability and the validity were tested for three coronal ultrasound angles: an automatic and manual SP angle and a manual TP angle as compared with the radiographic coronal main thoracic or (thoraco)lumbar Cobb angles. RESULTS: The ICC showed very reliable measurements of all ultrasound methods (ICC ≥0.84). The ultrasound angles were 15%-37% smaller as compared with the Cobb angles; however, excellent linear correlations were seen between all ultrasound angles and the Cobb angle (thoracic: R2≥0.987 and (thoraco)lumbar R2≥0.970), and the Bland-Altman plot showed a good agreement between all ultrasound angles and the Cobb angle. The MADs of the ultrasound angles, corrected using the linear regression equation, and the Cobb angles showed no significant difference between the different ultrasound angles (MAD: automatic SP angle 4.9°±3.2°, manual SP angle 4.5°±3.1°, and manual TP angle 4.7°±3.6°; p≥.388). CONCLUSIONS: Coronal ultrasound angles are based on different landmarks than the traditional Cobb angle measurement and cannot represent the same angle values. In this study, we found excellent correlations between the ultrasound and Cobb measurements, without differences in the reliability and validity between the ultrasound angles based on the SPs and TPs. Therefore, the severity of the deformity in patients with AIS can be assessed by ultrasound imaging, avoiding hazardous ionizing radiation and enabling more individualized patient care. It also opens possibilities for screening.

Accuracy of computed tomographic angiography and magnetic resonance angiography for diagnosing renal artery stenosis.

BACKGROUND: Timely, accurate detection of renal artery stenosis is important because this disorder may be a potentially curable cause of hypertension and renal impairment. OBJECTIVE: To determine the validity of computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) compared with digital subtraction angiography (DSA) for detection of renal artery stenosis. DESIGN: Prospective multicenter comparative study conducted from 1998 to 2001. Two panels of 3 observers judged CTA and MRA image data and were blinded to all other results. Digital subtraction angiography images were evaluated by consensus. SETTING: 3 large teaching hospitals and 3 university hospitals in the Netherlands. PATIENTS: 402 hypertensive patients with suspected renal artery stenosis were included. A group of 356 patients who underwent all 3 diagnostic tests was used for analysis. MEASUREMENTS: Reproducibility was assessed by calculating interobserver agreement. Diagnostic performance was evaluated in terms of sensitivity, specificity, and other diagnostic variables. Atherosclerotic stenoses of 50% or greater and fibromuscular dysplasia were considered clinically relevant. RESULTS: Twenty percent of patients who underwent all 3 tests had clinically relevant renal artery stenosis. Moderate interobserver agreement was found, with kappa values ranging from 0.59 to 0.64 for CTA and 0.40 to 0.51 for MRA. The combined sensitivity and specificity were 64% (95% CI, 55% to 73%) and 92% (CI, 90% to 95%) for CTA and 62% (CI, 54% to 71%) and 84% (CI, 81% to 87%) for MRA. LIMITATIONS: Eighteen percent of the patients were included nonconsecutively. Digital subtraction angiography may be an imperfect reference test. CONCLUSION: Computed tomographic angiography and MRA are not reproducible or sensitive enough to rule out renal artery stenosis in hypertensive patients. Therefore, DSA remains the diagnostic method of choice. *For a list of the other investigators and research coordinators who participated in RADISH, see the Appendix.

Ultrasound in the management of the position of the femoral head during treatment in a spica cast after reduction of hip dislocation in developmental dysplasia of the hip.

In this prospective study of 18 hips we compared the efficacy of ultrasound with CT in determining the position of the femoral head in a spica cast after closed or open reduction in children with developmental dysplasia of the hip. Ultrasound was performed through the perineal opening of the cast. With a transinguinal approach, the superior ramus of the pubis, the acetabulum, the femoral head and the femoral neck can be depicted in one plane. The CT and ultrasound images were blinded and reviewed by two of the authors. Ultrasound was inconclusive in the first two reductions since the perineal opening was too small to see all the landmarks in one plane. In the following 16 reductions the landmarks were well defined and interpretation of the CT and ultrasound was similar. The perineal opening in the spica cast should be made in such a way that the ultrasound probe can be positioned in the groin so that the landmarks can be shown in one plane.

Knee radiography in the diagnosis of skeletal dysplasias.

BACKGROUND: Flattening of the epiphyses of long bones is seen in several skeletal dysplasias and standardized measurements on a radiograph of the knee to detect skeletal dysplasias using this feature have been described. Since then only two other studies in which this method was used have been published, and both included only a small number of children and neither had a control group. In addition, the Dutch National Working Group on Skeletal Dysplasias began to have doubts about the reliability of the method. We therefore decided to re-evaluate its accuracy in a population of children with and without a skeletal dysplasia. OBJECTIVE: To determine the diagnostic value of standardized measurements on conventional AP radiographs of the knee in children with a skeletal dysplasia. SUBJECTS AND METHODS: We measured the distal femoral metaphysis and epiphysis according to the published method on conventional AP radiographs of the knee in 45 healthy children and 52 children with a skeletal dysplasia. We compared graphically the height of the distal femoral epiphysis with its width and with the width of the femoral metaphysis. Receiver operating characteristic (ROC) curves were calculated for each group of children. RESULTS: All graphs showed a considerable overlap between children with a skeletal dysplasia and healthy children. The size of the area under the ROC curves for the different groups was small, varying between 0.567 and 0.653. CONCLUSIONS: This method does not discriminate between children with a skeletal dysplasia and healthy children. We therefore consider it to be of little diagnostic value.

Clinical, radiological and functional follow-up after surgical decompression of double aortic arch.

BACKGROUND: Double aortic arch (DAA) is a congenital vascular anomaly that causes tracheal and oesophageal compression. It requires surgical intervention in patients with severe symptoms. OBJECTIVE: To evaluate the clinical, radiological and functional follow-up after surgical relief of the compression. MATERIALS AND METHODS: Ten children (seven boys) with DAA were operated on at a mean age of 1.3 years (range 0.2-7.5). At a mean age of 10.1 years (range 5-18 years), a follow-up study was performed that included clinical, radiological and functional parameters. RESULTS: Seven children reported only mild respiratory symptoms and some trouble with swallowing. Preoperative fluoroscopy with spot images showed the mean tracheal diameter at the level of stenosis to be 37+/-23% of the maximal diameter. At the time of follow-up, this was 70+/-13%. The mean of the oesophageal diameter was 39+/-20% preoperatively and 47+/-16% postoperatively. Maximal expiratory flow volume (MEFV) curves of seven children showed typical characteristics of intrathoracic upper airway obstruction. Mean peak expiratory flow was significantly reduced (77+/-10% of predicted, P<0.0001). Bronchial hyper-reactivity, tested by methacholine challenge, was found in two patients. CONCLUSIONS: There was marked relief of clinical symptoms after surgical decompression of DAA in all patients. In spite of this, radiological narrowing of trachea and oesophagus persisted and lung function results were abnormal at long-term follow-up.

Prevalence of atherosclerotic renal artery stenosis in patients starting dialysis.

BACKGROUND: Atherosclerotic renal artery stenosis (ARAS) can lead to end-stage renal failure (ESRF). We determined the prevalence of ARAS in patients 45 years of age or older starting renal replacement therapy. METHODS: Forty-nine of 80 consecutive patients (37 males, 12 females) starting renal replacement therapy in our centre gave informed consent and underwent spiral computed tomographic angiography of their renal arteries. A renal artery diameter reduction of 50% or more assessed by two radiologists was considered as a significant stenosis. RESULTS: Twenty of 49 patients (41%) had an ARAS, and in eight cases (16%) this was bilateral or unilateral with a single kidney. Women were more likely to have an ARAS than men; 75 (9/12) vs 30% (11/37, P<0.01). However, relatively more women declined participation. Non-participants and participants did not differ in respect to other relevant clinical data. Nonetheless, findings in these patients would be negative, the prevalence of ARAS would still be 31% in women and 22% in men (NS). In 13 patients with ARAS the registered diagnosis of ESRF either was hypertension, renovascular disease or unknown. Assuming that in these patients atherosclerotic renovascular disease was the cause of renal failure, a total of 13 patients (13/49, 27%) entered the dialysis programme because of this problem. CONCLUSIONS: These results suggest that ARAS is an important cause of ESRF.

Repeated intervention for in-stent restenosis of the renal arteries.

PURPOSE: To assess the long-term technical success of repeated endovascular intervention in stenosed renal artery stents. MATERIALS AND METHODS: Fifteen patients with stenoses >or=50% in a renal stent placed because of an ostial atherosclerotic renal artery stenosis were included in this study. In the presence of increased blood pressure or decreased renal function, the in-stent restenosis was treated with percutaneous transluminal angioplasty (PTA) in the stent or placement of a second stent if the stenosis was located too distally in the stent. The results of these repeat interventions were evaluated by angiography. RESULTS: The 15 patients had a total of 20 stenosed stents. Eighteen of these in-stent stenoses were treated with PTA and two were treated with placement of a second stent. Angiographic follow-up was available in 16 arteries, showing in-stent restenosis in four (25%; mean follow-up, 11 mo). The cumulative patency rates after repeat endoluminal intervention were 93% (95% CI: 80%-106%) and 76% (95% CI: 52%-101%) after 6 and 12 months, respectively. Renal function remained stable or improved in most patients (80%) after repeated intervention in the stent, and hypertension was classified as improved or cured in 47% of patients after 1 year. CONCLUSION: Patients with stenosed renal artery stents can be treated successfully with PTA in a majority of cases, with a long-term success rate of 75% and stable renal function 1 year after repeated intervention.

MR urography for the preoperative evaluation of living renal donors.

The purpose of this study was to assess the image quality and diagnostic value of MR urography in detecting abnormalities of the urinary collecting system relevant for the preoperative evaluation of living renal donors. Study subjects were selected from the existing intravenous urography (IVU) reports: 18 consecutive patients with a duplication or another abnormality of the collecting system and 20 consecutive patients with normal anatomy. They underwent a respiratory-triggered 3D T2-weighted fast spin-echo acquisition after oral administration of furosemide, without and with abdominal compression. The MR images were evaluated by two independent blinded observers. The IVU was used as the standard of reference. Image quality of the MR urograms with compression was overall better than those without compression, and the former were regarded as adequate for the evaluation of small filling defects and deformities of the pelvis and calyces in 76-81% of the kidneys and 74-79% of the patients. Both observers correctly diagnosed all 13 kidneys with a partial or complete duplication. The image quality of MR urography was inadequate to evaluate the calyces and pelvis for small filling defects or deformities in approximately 25% of the patients; however, the technique was accurate in the detection of abnormalities of the urinary collecting system relevant for the preoperative evaluation of living renal donors.