Does software optimization influence the radiologists' perception in low dose paediatric pelvic examinations?

PURPOSE: To investigate whether software optimisation can improve an observers' perception of image quality in low dose paediatric pelvic examinations. METHODS: Twenty-five consecutive patients (3-7 years old) were referred for a pelvic digital radiography (DR) examination. They were prospectively enrolled in the study over a 3-month period. Images were taken at 80 kV and 2-4 mAs depending on pelvic thickness (9-15 cm). A small focal spot, 130 cm SID: 10 cm air gap and 1 mm Al and 0.2 mm Cu additional filtration were also utilised. Images were acquired on a Canon DR detector and optimised using five different combinations of the multi-frequency processing software (Canon DR system version NE, Version 7.1 with SPECTRA) to comply with the ALARA principle. Image quality was blindly evaluated using the subjective Visual Grading Analysis (VGA) by five experienced musculoskeletal radiologists, including the evaluation of six anatomical image quality criteria (scored from 1 to 5). RESULTS: Consistently, the VGA results indicated that by using software optimised parameters, image quality was suitable for diagnosis in 48-71% of all images. Based on a VGC analysis all software optimised images did have significant better image quality then the one with just the clinical settings. Noise reduction was the software setting which influenced the image quality the most, area under the curve (AUC) of 0.8172 95%CI 0.7953-0.8375. CONCLUSION: Software optimisation improve the radiologists' perception of image quality and should thus be thoroughly considered within clinical practise. Noise reduction is the software parameter which has the greatest influence.

A comparison of a non-ionic dimer, iodixanol with a non-ionic monomer, iohexol in low dose intravenous urography.

A prospective, double-blind study of 392 patients randomized into four groups was performed to establish whether diagnostic intravenous urograms could be obtained with a lower dose of iodine when using the dimeric, non-ionic contrast medium iodixanol compared with the monomeric, non-ionic iohexol. Patients received iodixanol or iohexol containing either 9 or 12 g of iodine (gI). The primary parameter was the diagnostic quality of the 6 min film, assessed in a blinded fashion, by consensus, by four radiologists. Iodixanol at both doses was diagnostic in over 90% of cases. Iohexol was only diagnostic in 74% (9 gI) and 81.8% (12 gI). Pairwise comparisons revealed that iodixanol 9 gI was significantly better than both iohexol 9 gI (p = 0.0005) and 12 gI (p = 0.014). No significant difference was present for different doses within the same contrast medium group. Iodixanol resulted in poorer bladder distension than iohexol. Iodixanol caused significantly less discomfort than iohexol.

Computerised tomography after posterior dislocation of the hip.

We have reviewed 19 consecutive patients admitted to the Odense University Hospital after traumatic dislocation of the hip. We aimed to perform computerised tomography as soon as possible after closed reduction; this was accomplished in 15 patients. The CT scans revealed intra-articular fragments of bone in five hips, and fractures of the femoral head or acetabulum in six. In two cases the CT scans excluded fractures or intra-articular fragments which had been suspected on conventional radiography. CT scanning is a useful diagnostic tool in traumatic dislocation of the hip; we consider that it makes an important contribution to management.

Quality of reduction and cortical screw support in femoral neck fractures. An analysis of 72 fractures with a new computerized measuring method.

The aim of this study was to compare the quality of reduction and the position of the fixating screws with the rate of union in 72 femoral neck fractures. The degree of fracture displacement after reduction and the position of the two fixating screws were determined with a new computerized measuring method that compensates for the variations in hip rotation in routine radiographs. All 13 nondisplaced fractures united. Sixteen of 18 fractures healed in the group of displaced fractures where both the fixating screws were placed within 3 mm from the femoral neck cortex, compared with 13 of 22 healed fractures in the group where only one screw had the same close contact with the femoral neck cortex (p < 0.05). Nonunion developed in all five displaced fractures where none of the two fixating screws were placed within 3 mm from the femoral neck cortex. The quality of reduction did not affect the healing rate; however, the number of poorly reduced fractures was only 10%. The results of this study underline the importance of achieving cortical support for the fixating screws in femoral neck fracture surgery.

Treatment of solitary enchondromas in fingers.

The results after operative treatment of 21 solitary enchondromas of finger bones are described. 15 cases were treated by curettage and cancellous bone grafting, five by curettage alone, and one with amputation. One case did not heal after curettage and grafting. When symptoms are present or the cortical strength is decreased, we recommend operation. We find that the eccentric type of enchondroma can be treated adequately by curettage alone, while curettage and filling of the cavity with cancellous bone should be preferred in the central and polycentric forms. It is important that all material is removed from the cyst, which has to be packed completely with bone chips. The possibility of malignant change in enchondromas should be borne in mind, but we did not see this.

PINTRACE: a computer program for assessment of pin positions in routine radiographs of femoral neck fractures.

A new method for determination of pin positions in internally fixated femoral neck fractures is described. In AP and lateral radiographs of the hip, measurements are made of the cervicofemoral angles, the diameter of the femoral head and neck, and the distances from the central femoral neck axis to each pin. From these values the positions of the fixation pins in defined straight AP and lateral projections are determined by geometric calculations. A computer program in BASIC was developed to perform the calculations and to produce graphic displays of cross-sections of the femoral head and neck with the corrected pin positions indicated. For routine radiographic examinations with unknown inclination angles of the X-ray beams, the error of the method is less than 5% of the femoral head diameter. With conventional methods of determining pin positions the error can exceed 25% of the femoral head diameter.

An algorithm for preoperative prediction of reoperation risk after internal fixation of femoral neck fractures.

An algorithm was designed for preoperative prediction of the risk for reoperation, and the mortality risk, after internal fixation of femoral neck fractures. Out of 51 reviewed studies of femoral neck fractures, eight met specified inclusion criteria such as low dropout rates, a minimum of ten surgeons performing the surgery, a minimum of 2 years follow-up, and a standard age, sex, and Garden class distribution. Five of these studies were used for the construction of the algorithm, and the remaining three for testing the specificity and sensitivity of the algorithm. A separate analysis of the influence of age on the reoperation rate was also performed. In the analysis of 399 reviewed cases of femoral neck fractures, the specificity for the algorithm in predicting the risk for reoperation was 96%, and the sensitivity was 51%. The positive predictive value for the algorithm in predicting the risk for reoperation was 77%, which was three times higher compared to the commonly used predictors age and Garden class (positive predictive value 25%). For prediction of the mortality risk the positive predictive value for-the algorithm was 57%.

An algorithm for assessment of fracture displacement and pin positions in femoral neck fractures.

A method for determination of both the displacement of the femoral head and the position of the fixation device in fixed femoral neck fractures is described. In routine AP and lateral radiographs of the hip, measurements are made of femoral neck-shaft angle, the diameter of the femoral head and neck, the distances from the center of the femoral head to the femoral neck axis and the distances from the femoral neck axis to the fixating screws. From these values the position of the femoral head and the fixating screws are determined by geometric calculations. A computer program in Q-BASIC was devised to perform the calculations and to produce graphic displays of cross-sections of the femoral head and neck, with the displacement of the head and the screw positions indicated. The accuracy of the method was evaluated by a new method using axial radiographs of hip specimens, which were compared with the computer-plotted graphs of the femoral head and neck. The mean error of the method was found to be +/- 5% of the femoral head diameter, approximately 2.5 mm.

[Magnetic resonance imaging in musculoskeletal tuberculosis]. / Magnetisk resonans-scanning ved muskuloskeletal tuberkulose.

The incidence of tuberculosis in Denmark has increased over the last years. Two cases of primary osteoarticular tuberculosis are described: tuberculous ostitis of the scapula and surrounding soft tissue, and tuberculosis of the elbow. We have emphasized the appearance on magnetic resonance imaging (MRI), as the role of this modality has only been sporadically described for osteoarticular tuberculosis in areas other than the vertebral column. The cases show that MRI can contribute to a more precise determination of the extent of osteoarticular tuberculosis and its soft tissue involvement.

[Subscapular elastofibroma]. / Subskapulaert elastofibrom.

Elastofibroma dorsi (EF) is a rare and benign connective-tissue tumour, typically localized between the lower part of the scapula and the chest wall. Two case stories of EF are presented. The etiology, symptoms, diagnostics and treatment are discussed.

[Early treatment with nasal continuous positive airway pressure and "minimal handling". Early and late prognosis in children with birth weight under 1,501 g]. / Tidlig behandling med nasalt kontinuerligt overtryk i luftvejene og "minimal handling". Tidlig- og senprognose hos børn med fødselsvoegt < 1.501 g.

During 1988 and 1989 a regional cohort of 81 infants with birth weights of less than 1501 g were treated with oxygen (n = 11), early continuous positive airway pressure (CPAP) (n = 68) or mechanical ventilation from birth (n = 2). We used an easily applicable lightweight CPAP system with nasal prongs and a gas jet supplemented with ventilator treatment if necessary, but with conservative criteria for ventilator treatment with tolerance of high PCO2. A total of 65 infants (80%) survived to discharge, 61 of whom were supported solely with CPAP or oxygen. Nineteen infants (26%) developed periventricular-intraventricular haemorrhage, but only four survivors (6%) developed prognostically significant bleedings of grade 2-4. No survivors had bronchopulmonary dysplasia. Follow-up at 1.5-5 years of age revealed definite disabilities in seven (11%). The results suggest that treatment by early CPAP with nasal prongs with tolerance of high PCO2 may be effective and lenient in most infants of more than 25 weeks' gestation.

[MRI scanning in suspected fractures of the scaphoid bone]. / MR-scanning ved mistanke om fraktur af os scaphoideum.

MR examination was performed in 20 patients clinically suspected of having a fracture of the scaphoid bone. The patients also followed the normal routine with conventional radiographs in the acute fase and after 10-12 days. The MR was in most cases performed within a day after the trauma. All fractures seen on conventional radiographs were depicted on MR. MR further showed four fractures, five bone contusions (bone bruise) and lesions of the soft tissues in 75% of the patients. In patients with suspected fracture of the scaphoid, MR seems to be the best primary imaging method and displays a wide range of lesions.