The cost of perfection: An investigation into the unnecessary rejection of clinically acceptable lateral wrist imaging.

INTRODUCTION: This study illustrates image rejection rates of the lateral wrist x-ray projection at a large, public teaching hospital. Rejected images were evaluated to determine the number of images that needed to be repeated based on the clinical indication. This study highlights the difference in subjective image-repeat decision-making skills existing between radiologists, experienced radiographers and junior radiographers. METHODS: A retrospective review was conducted of all rejected lateral wrist x-ray images by a panel of three radiologists, three experienced radiographers and six junior radiographers. This review aimed to determine if rejected imaging met the consideration of the clinical indication and assumed appropriate acquisition of an orthogonal projection. A complement of images that had not been rejected were included in the review to create a blinded study. RESULTS: The review demonstrated 85.8% of rejected images were deemed to meet clinical requirements according to radiologists. The experienced radiographers agreed with radiologists regarding 75.3% of images. Junior radiographers agreed with radiologists in 34.2% of cases. Junior radiographers were three times more likely to seek repeat imaging than the radiologists and experienced radiographers. CONCLUSIONS: This review demonstrated a lateral wrist projection reject rate of 38.7% with unnecessary repeats according to clinical indications in 85.8% of cases. The review of experienced radiographers was comparable to radiologists; however, the difference in decision-making skills was evident in the junior radiographers. This highlights an alarming trend, should similar results be demonstrated at other health services and indicates an unnecessary burden to clinical practice. Inclusion of clinical reasoning for imaging and the need for repeat imaging is recommended for radiography training programs.

Pre-operative templating for total hip arthroplasty: How does radiographic technique and calibration marker placement affect image magnification?

INTRODUCTION: Pre-operative templating using digital radiography is an effective method of planning for total hip arthroplasty (THA) and requires a generalised fixed magnification factor (MF) or external calibration markers (ECM). The effect on image magnification when changing source-to-image distance (SID), object-to-image distance (OID) and different imaging conditions is not well described. This study aims to quantify the range of effects manipulation of radiographic parameters can have on image magnification across different body habitus and imaging conditions. METHODS: A simple phantom study was performed. A 25 mm ECM was placed at eight different OID values along the anterior-posterior phantom plane at three different SID values and imaging conditions, and X-rays were obtained. On each radiograph, the ECM was measured using a line calliper tool by three radiographers and recorded. The MF was calculated and recorded. RESULTS: The smallest observed image MF was 1.16, for an 8 cm OID, 120 cm SID with the ECM placed within the central ray and the X-ray detector in bucky underneath the X-ray table. The largest image MF was 1.40 for a 15 cm OID, 100 cm SID with the X-ray detector placed underneath an emergency department imaging trolley. CONCLUSIONS: Digital pre-operative templating for THA relies on accurate radiographic positioning and is dependent of the patient body habitus, radiographic parameters and imaging conditions selected by the radiographer. The use of appropriately positioned ECMs - placed medially between the patient's internally rotated legs at the level of the greater trochanter, lowers the potential for magnification inaccuracies.

An evaluation of the effect of tube potential on clinical image quality using direct digital detectors for pelvis and lumbar spine radiographs.

INTRODUCTION: High kVp techniques, 15% or 10-kVp rules, are well-known dose reduction methods. Traditionally, the use of high tube potential (i.e. increased kVp) is associated with decreased radiographic contrast and overall image quality. Recent studies suggest contrast and image quality are not heavily reliant on kVp with digital systems. This study aims to assess the effects of the high tube potential technique on clinical radiographic image quality when using digital systems, to validate high kVp as a dose saving technique. METHODS: A selection of comparable pelvis and lumbar spine radiographs were collected from the hospital's picture archiving and communication system (PACS), with technical factors recorded. All clinical radiographs were assessed by 5 senior radiographers using a 15-point visual grading analysis (VGA) rubric. RESULTS: For 40 AP pelvis radiographs and 40 lateral lumbar spine radiographs, reduction in the dose area product (DAP) with higher kVp is seen. Average pelvis DAP at 75 kVp = 14.06 mGy.cm2 ; 85 kVp = 7.47 mGy.cm2 . Average lumbar spine DAP at 80 kVp = 15.76 mGy.cm2 ; 90 kVp = 14.83 mGy.cm2 . Image quality and contrast scores showed no statistically significant difference between the high and low kVp groups (z = 0.06 and 0.12, respectively). Average pelvis VGA score at 75 kVp = 11.26; 85 kVp = 12.55. Average lumbar spine VGA score at 80 kVp = 9.23; 90 kVp = 10.64. CONCLUSIONS: The high tube potential techniques allowed for reduced patient radiation doses whilst showing no degradation of diagnostic image quality in a clinical setting. This study successfully validates the high kVp technique as a useful tool for reducing patient radiation doses whilst maintaining high diagnostic image quality for digital pelvis and lumbar spine radiography.

Carbon dioxide CT angiography during endovascular treatment of bilateral common iliac disease with angio-CT utilisation.

This paper presents the application of carbon dioxide for CT imaging during an endovascular procedure to help characterise unexpected bilateral common iliac artery stenosis utilising an angio-CT system, confirming its application in interventional radiology while maintaining sterility. A 78 year old male was referred to the Radiology Interventional Suite with left lower limb rest pain. On imaging via digital subtraction angiography and CT utilising both iodinated contrast and carbon-dioxide (CO2 ), endovascular treatment of bilateral CIA stenosis was performed with good clinical result. The case presented demonstrates the advanced imaging techniques possible in suites that have ready access to angiography and conventional CT. CO2 CT angiography is optimally performed on combined Angio-CT systems where CT and angiography system are integrated into a single room.