Comprehensive optimization process of paranasal sinus radiography.

BACKGROUND: The optimization of radiological examinations is important in order to reduce unnecessary patient radiation exposure. PURPOSE: To perform a comprehensive optimization process for paranasal sinus radiography at Mikkeli Central Hospital, Finland. MATERIAL AND METHODS: Patients with suspicion of acute sinusitis were imaged with a Kodak computed radiography (CR) system (n=20) and with a Philips digital radiography (DR) system (n=30) using focus-detector distances (FDDs) of 110 cm, 150 cm, or 200 cm. Patients' radiation exposure was determined in terms of entrance surface dose and dose-area product. Furthermore, an anatomical phantom was used for the estimation of point doses inside the head. Clinical image quality was evaluated by an experienced radiologist, and physical image quality was evaluated from the digital radiography phantom. RESULTS: Patient doses were significantly lower and image quality better with the DR system compared to the CR system. The differences in patient dose and physical image quality were small with varying FDD. Clinical image quality of the DR system was lowest with FDD of 200 cm. Further, imaging with FDD of 150 cm was technically easier for the technologist to perform than with FDD of 110 cm. CONCLUSION: After optimization, it was recommended that the DR system with FDD of 150 cm should always be used at Mikkeli Central Hospital. We recommend this kind of comprehensive approach in all optimization processes of radiological examinations.

Verification of palpation-guided intra-articular injections using glucocorticoid-air-saline mixture and ultrasound imaging (GAS-graphy).

OBJECTIVE: To examine a contrast medium method using a glucocorticoid-air-saline mixture and ultrasound imaging (GAS-graphy) for the verification of palpation-guided injections in different joints and to assess the inter-reader reliability of the method. METHODS: A palpation-guided injection of an air-steroid-saline mixture was given into a joint or tendon sheath of 133 consecutive patients. The dynamic ultrasound monitor images of the joints and tendons involved were videotaped before and after the injection. A rheumatologist and two radiologists analyzed separately the video clips of each patient, under blinded conditions. The readers evaluated the accuracy of the injections and the difficulty of the reading process. The inter-reader agreement was assessed by calculating the percentual values and overall kappa coefficient between the readers. RESULTS: The overall accuracy of the successful injections was 76%, 80% and 82 % evaluated by the three readers. In six out of the ten injection sites the accuracy was higher than 80%. The clarity of the method evaluated by the readers was 8, 8 and 8.5 on a scale from 0 to 10. The inter-reader agreement assessed by percentual values was 84.2%, 85.0% and 88.7%. The kappa coefficient between all readers was 0.595 showing moderate agreement. CONCLUSION: The GAS-graphy method for the verification of palpation-guided injections is a simple procedure performable to any joint site and the result can be seen immediately on the monitor after the injection. The reliability of the method is good and it can be used in developing injection techniques as well as in medical or nurse education. The method can be used as an alternative for the radiographic contrast medium method in verifying successful palpation-guided intra-articular injections.

Power Doppler ultrasonography and synovitis: correlating ultrasound imaging with histopathological findings and evaluating the performance of ultrasound equipments.

OBJECTIVES: To examine the validity of power Doppler ultrasound imaging to identify synovitis, using histopathology as gold standard, and to assess the performance of ultrasound equipments. METHODS: 44 synovial sites in small and large joints, bursae and tendon sheaths were depicted with ultrasound. A synovial biopsy was performed on the site depicted and a synovial sample was taken for histopathological evaluation. The performance of three ultrasound devices was tested using flow phantoms. RESULTS: A positive Doppler signal was detected in 29 of 35 (83%) of the patients with active histological inflammation. In eight additional samples, histological examination showed other pathological synovial findings and a Doppler signal was detected in five of them. No significant correlation was found between the amount of Doppler signal and histological synovitis score (r = 0.239, p = NS). The amount of subsynovial infiltration of polymorphonuclear leucocytes and surface fibrin correlated significantly with the amount of power Doppler signal: r = 0.397 (p<0.01) and 0.328 (p<0.05), respectively. The ultrasound devices differed in showing the smallest detectable flow. CONCLUSIONS: A negative Doppler signal does not exclude the possibility of synovitis. A positive Doppler signal in the synovium is an indicator of an active synovial inflammation in patients. A Doppler signal does not correlate with the extent of the inflammation and it can also be seen in other synovial reactions. It is important that the quality measurements of ultrasound devices are reported, because the results should be evaluated against the quality of the device used.

Assessing the intra- and inter-reader reliability of dynamic ultrasound images in power Doppler ultrasonography.

OBJECTIVE: To assess the intra-reader and inter-reader reliabilities of interpreting ultrasonography by several experts using video clips. METHOD: 99 video clips of healthy and rheumatic joints were recorded and delivered to 17 physician sonographers in two rounds. The intra-reader and inter-reader reliabilities of interpreting the ultrasound results were calculated using a dichotomous system (normal/abnormal) and a graded semiquantitative scoring system. RESULTS: The video reading method worked well. 70% of the readers could classify at least 70% of the cases correctly as normal or abnormal. The distribution of readers answering correctly was wide. The most difficult joints to assess were the elbow, wrist, metacarpophalangeal (MCP) and knee joints. The intra-reader and inter-reader agreements on interpreting dynamic ultrasound images as normal or abnormal, as well as detecting and scoring a Doppler signal were moderate to good (kappa = 0.52-0.82). CONCLUSIONS: Dynamic image assessment (video clips) can be used as an alternative method in ultrasonography reliability studies. The intra-reader and inter-reader reliabilities of ultrasonography in dynamic image reading are acceptable, but more definitions and training are needed to improve sonographic reproducibility.

Use of air-steroid-saline mixture as contrast medium in greyscale ultrasound imaging: experimental study and practical applications in rheumatology.

OBJECTIVES: To investigate experimentally the echogenicity of air, a steroid suspension and physiological saline mixed with water in order to find the best contrast medium for injections. To show the practical applications of an airsteroid-saline mixture as a contrast medium in rheumatology. METHODS: In vitro. First, quality assurance measurements were conducted twice on the ultrasound (US) equipment. Subsequently air, a steroid suspension, or physiological saline mixed with water, first alone and then in different combinations, were examined with US using quantitative image analysis. Clinical. The effectiveness of an air-steroid-saline mixture as contrast medium in ultrasonography was tested in joint, bursa and tendon sheath injections. RESULTS: In vitro. Based on the quality assurance measurements the physical performance of the US equipment was excellent. Verified visually and quantitatively the mixture of air, steroid and saline produced the best contrast on US. The importance of air bubbles producing contrast was obvious. Clinical application. Firstly, visualisation of the contrast medium with US made it possible to follow in real-time the passage of a drug to the target area. Secondly, the use of the contrast method verified the presence of steroid in the synovial target intended after a blind injection. Thirdly, anatomical and pathologic anatomical connections could be visualized using this contrast medium in the wrist, shoulder, knee, ankle and foot joint CONCLUSIONS: Verification of US system performance by quality assurance measurement is essential for US imaging. The air-steroid-saline contrast medium method of ultrasound scanning is a somewhat invasive, but inexpensive and rapid method. It can verify the existence or non-existence of an air-steroid-saline contrast medium in the desired place and in adjacent structures, thus showing possible pathologic anatomic connections. The method has a diagnostic and therapeutic value, and expands the interventional spectrum of sonographic imaging.

Quality of dynamic radionuclide renal imaging: multicentre evaluation using a functional renal phantom.

The aim of this study was to evaluate the quality of dynamic radionuclide renal imaging in Finland. Nineteen nuclear medicine departments participated. A functional renal phantom was imaged and interpreted as a patient-like study. Reconstruction and printouts were performed according to the clinical routine of each laboratory. Three nuclear medicine specialists anonymously evaluated the quality of the image sets. The visual scores of the experts were ranked from one to five. In addition, several numerical time-activity parameters were calculated and compared between the laboratories. The average visual scores of the experts for the image sets were 3.2+/-0.5 (range 2.4-4.2). Only two laboratories received a score value of 4 or higher. The average error for the time to reach maximum activity (T(max)) ranged from -29 to +18% and for the washout time to reach half activity from maximum activity (T(1/2)) ranged from -43 to +66%. These results suggest that the difference in calculated parameters between laboratories is most probably due to variations in study protocols and analysis programmes. The need for external quality assurance and quality improvement in nuclear renal imaging is evident and is recommended for regular use.

A dynamic phantom for radionuclide renography.

The aim of the study was to develop and test a dynamic phantom simulating radionuclide renography. The phantom consisted of five partly lead covered plastic containers simulating kidneys, heart, bladder and background (soft tissues, liver and spleen). Dynamics were performed with multiple movable steel plates between containers and a gamma camera. Control of the plates is performed manually with a stopwatch following exact time schedules. The containers were filled with activities (99mTc) which produce count rates close to clinical situations. Count rates produced by the phantom were compared with ten clinical renography cases: five 99mTc MAG3 and five 99mTc DTPA examinations. Two phantom simulations were repeated three times with separate fillings, acquisitions and analyses. Precision errors as a coefficient of variation (CV) of repeated measurements were calculated and theoretical values were compared with the corresponding measured ones. A multicentre comparison was made between 19 nuclear medicine laboratories and three clinical cases were simulated with the phantom. Correlations between count rates produced by the phantom and clinical studies were r = 0.964 for 99mTc MAG3 (p < 0.001) and 0.961 for 99mTc DTPA (p < 0.001). The precision error was 4.5 +/- 3.2% and the percentage difference between theoretical and measured values for Tmax was 4.0 +/- 1.6%. Images and curves of the scanned phantom were close to a real patient in all 19 laboratories but calculated parameters varied: the difference between theoretical and measured values for Tmax was 6.8 +/- 6.2%. The difference between laboratories is most probably due to variations in acquisition protocols and analysis programs: 19 laboratories with 18 different protocols and 8 different programs. The dynamics were found to be repeatable and suitable for calibration purposes for radionuclide renography programs and protocols as well as for multicentre comparisons.