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.

Clinical magnetic resonance imaging and arthroscopic findings in knees: a comparative prospective study of meniscus anterior cruciate ligament and cartilage lesions.

We compared the diagnostic and predictive value of magnetic resonance imaging (MRI) and clinical findings with arthroscopy in 61 knees in a prospective study. In meniscal tears, the accuracy and positive predictive value of MRI was found to be nearly twice that of clinical examination. The sensitivity, specificity, and negative predictive value of MRI were comparable to the figures found in other studies. We recommend MRI as a clarifying diagnostic tool when a clinical examination indicates a lesion of the meniscus. In our study, the clinical relevance of MRI in anterior cruciate ligament lesions and especially in cartilage lesions was more doubtful. The combination of clinical and MRI findings would reduce the number of blank arthroscopies to 5%. MRI is a valuable diagnostic tool in planning the type of anesthesia and treatment, and could significantly reduce the need for a second arthroscopy.

Basolateral binding and uptake of 125-I-insulin in proximal tubular cells after peritubular extraction in the avian kidney.

Several studies have suggested the existence of a renal peritubular extraction of insulin. So far, however, no conclusive evidence, as to whether insulin enters the proximal tubular cell following peritubular extraction, has been presented. In the present study we injected iodine labelled porcine insulin into the renal portal system on hens prepared according to a modified Sperber technique and followed cellular handling of the extracted 125-I-insulin using electron microscope autoradiography at 1 and 7 min after injection. The results showed that at 1 min after injection, peritubular extraction of 125-I-insulin accounted for as much as 30% of total proximal tubular accumulation of grains. Of these grains about 40% were located over basal vesicles, lysosomers or other cell organelles with the remaining 60% located in the intercellular space, probably bound to the basolateral membrane. At 7 min after injection the distribution of grains subsequent to peritubular extraction of 125-I-insulin was unchanged. In contrast, very few grains were located over distal tubules at 1 or 7 min. Thus, the results demonstrate a sizable peritubular extraction of 125-I-insulin in the avian kidney with subsequent uptake into the proximal tubular cells of about one third of the extracted insulin.

Luminal uptake and intracellular transport of insulin in renal proximal tubules.

It is generally accepted that proteins taken up from the renal tubular fluid are transported into lysosomes in proximal tubule cells. Recently, however, it has been postulated that insulin in isolated perfused rat kidneys did not accumulate in lysosomes but to a certain degree in the Golgi region. The present study was undertaken to investigate the intracellular handling of biologically unaltered insulin in rat renal proximal tubule cells. Rats were prepared for in vivo micropuncture and either a colloidal gold insulin complex or insulin monoiodinated in the A-14 position (125I-insulin) was microinfused into proximal tubules. After 5, 10, 25 or 60 min the tubules were fixed by microinfusion of glutaraldehyde and processed for electron microscopy or electron microscope autoradiography. A qualitative analysis of tubules infused with colloidal gold insulin or 125I-insulin showed that insulin was taken up by endocytosis and transported to lysosomes, and a quantitative autoradiographic analysis of the 125I-insulin microinfused tubules showed that the grain density after five min was significantly increased for endocytic vacuoles and for lysosomes. After 60 min the grain density was still significant over lysosomes. The accumulation of grains was non-significant over all other areas analyzed at any time. This study shows that insulin is taken up from the luminal side of the proximal tubule by endocytosis and transported to the lysosomes. There was no significant transport to the Golgi region.