Incidental central pulmonary emboli in outpatients with deep vein thrombosis.

BACKGROUND: While it has been demonstrated that large asymptomatic pulmonary embolism (PE) can occur, many studies have assessed inpatients or patients with known risk factors for venous thromboembolism (such as malignancy). There are few data regarding incidental PE in outpatients with deep vein thrombosis (DVT) or assessing whether these emboli occur centrally or peripherally in the pulmonary arteries. AIMS: To determine the rates of incidental central and peripheral PE in outpatients with proximal and distal DVT. METHODS: This was a retrospective cross-sectional study of 120 patients attending our community imaging clinic between January 2015 and March 2020, with ultrasound-confirmed lower limb DVT, and subsequent computed tomography pulmonary angiogram (CTPA) within 24 h. Exclusion criteria were symptoms indicative of PE. Imaging reports were retrospectively reviewed to record the proximity of DVT and the location of any PE as either central (pulmonary trunk or main pulmonary arteries) or peripheral (lobar, segmental or subsegmental pulmonary arteries). RESULTS: Incidental PE occurred in 71 patients (59.2%), with a rate of 77.5% in proximal and 50.0% in distal DVT. Sixteen patients had central PE (13.3% of all patients with DVT; 22.5% of all patients with PE). Two patients (both with proximal DVT) had PE in the pulmonary trunk. CONCLUSIONS: Incidental PE occur frequently in outpatients with lower limb DVT, including the possibility of asymptomatic central emboli. Further studies with larger patient cohorts would be useful to assess the utility of baseline chest imaging in outpatients with DVT.

Rising use of diagnostic imaging in Australia: An analysis of Medicare-funded radiology services between 2000 and 2021.

INTRODUCTION: The use of diagnostic imaging services is increasing worldwide. This has important impacts on healthcare resource allocation and potential risks to the population. This study aimed to quantify trends in medical imaging in Australia over the past two decades. METHODS: Data were extracted from the Australian Medicare Benefits Schedule (MBS) between 2000 and 2021. Simple linear regression analyses were performed to assess changes in absolute utilisation and utilisation rate per 100,000 population of total imaging services as well as by each imaging modality. Logistic regression analysis was performed to assess changes in total imaging services as a proportion of total Medicare services over time. Chi-squared test was used to assess for change in modality composition of imaging services. RESULTS: There were 436,255,500 imaging studies performed between 2000 and 2021. The absolute utilisation of total imaging services increased annually by an average of 864,404 (95% CI: 808,235-920,573, p < 0.001). For each consecutive year, the proportion of total Medicare services attributed to total imaging services increased by 0.01% (95% CI: 0.01-0.01, p < 0.01). There was also a statistically significant increase in the utilisation rates of imaging services per 100,000 population for each imaging modality. The number of imaging services per radiologist increased on average by 74 (95% CI: 26-122, p < 0.05) annually. CONCLUSION: The utilisation of diagnostic imaging services has increased in Australia between 2000 and 2021, outpacing the population growth, total healthcare services, and the radiologist workforce.

Necessity of performing a routine chest radiograph following the insertion of tunnelled Hickman catheter under imaging guidance: A single centre experience.

INTRODUCTION: A chest radiograph has traditionally been performed following the insertion of a tunnelled Hickman catheter to immediately exclude rare but potentially serious complications such as pneumothorax and haemothorax and confirm appropriate positioning of the catheter tip. The value of completing the routine chest radiograph has been questioned when fluoroscopic image may be easily obtained in the angiography suite for the same purpose, and the rate of iatrogenic pneumothorax remains extremely low in the Medical literature. We describe our experience of performing Hickman catheter insertion under ultrasound and fluoroscopic guidance and whether routinely performing the chest radiograph is justifiable. METHODS: A single centre retrospective review was performed of patients who received a tunnelled Hickman catheter and underwent postprocedural chest radiograph in the Interventional Radiology Department during a fifteen-year period from August 2007 to April 2021. Patient demographics and complications were documented. RESULTS: Delayed iatrogenic pneumothorax was diagnosed in one asymptomatic patient (0.06%) on a chest radiograph out of 1735 patients, and they required chest tube insertion. Other complications included two cases of right common carotid artery puncture, one case of right internal jugular vein dissection and one case of left internal jugular perforation. Two patients required a repeat procedure within 24 h due to superior migration of the Hickman catheter on chest radiograph. CONCLUSION: Given the extremely low rate of iatrogenic pneumothorax, chest radiograph following the insertion of a tunnelled Hickman catheter under ultrasound and fluoroscopic guidance may be an unnecessary investigation unless the patient is symptomatic, or there is sufficient clinical concern.

Indirect Lung Absorbed Dose Verification by 90Y PET/CT and Complete Lung Protection by Hepatic Vein Balloon Occlusion: Proof of Concept.

Postradioembolization lung absorbed dose verification was historically problematic and impractical in clinical practice. We devised an indirect method using 90Y PET/CT. Methods: Conceptually, true lung activity is simply the difference between the total prepared activity minus all activity below the diaphragm and residual activity within delivery apparatus. Patient-specific lung mass is measured by CT densitovolumetry. True lung mean absorbed dose is calculated by MIRD macrodosimetry. Results: Proof of concept is shown in a hepatocellular carcinoma patient with a high lung shunt fraction of 26%, where evidence of technically successful hepatic vein balloon occlusion for radioembolization lung protection was required. Indirect lung activity quantification showed the postradioembolization lung shunt fraction to be reduced to approximately 1% with a true lung mean absorbed dose of approximately 1 Gy, suggesting complete lung protection by hepatic vein balloon occlusion. Conclusion: We discuss possible clinical applications such as lung absorbed dose verification, refining the limits of lung tolerance, and the concept of massive activity radioembolization.

The impact of the COVID-19 pandemic on diagnostic imaging services in Australia.

INTRODUCTION: The COVID-19 pandemic is driving unprecedented changes in healthcare services worldwide. This study aimed to quantify the impact of the first wave of the COVID-19 pandemic on diagnostic imaging services in Australia using an interrupted time series model. METHODS: Monthly data were extracted from the Australian Medicare Benefits Schedule for all diagnostic imaging services performed between January 2016 and December 2019. Holt-Winters forecasting models were developed for total imaging services as well as for each imaging modality. The models were used to predict monthly data between January 2020 and June 2020 with a 95% confidence interval (P < 0.05). Absolute and percentage residual differences (RD) between observed and predicted services for this time period were calculated. RESULTS: There were statistically significant reductions in total imaging services performed in March 2020 (RD: -332260, -13.1%, 95% CI: -17.5% to -8.4%), April 2020 (RD: -716957, -32.4%, 95% CI: -36.2% to -28.1%) and May 2020 (RD: -571634, -21.4%, 95% CI: -25.1% to -17.3%). Nuclear medicine and CT services were relatively less impacted than general radiography, ultrasound, and MRI services. There was also a statistically significant increase in nuclear medicine and CT services performed in June 2020 compared to predicted values. CONCLUSIONS: During the first wave of COVID-19 in Australia, there was a significant reduction in total diagnostic imaging services, with variable impacts on different imaging modalities. These findings may have significant public health implications and can be used to inform evidence-based strategies in the recovery phase of the pandemic.

Radiological findings of e-cigarette or vaping product use associated lung injury: A systematic review.

INTRODUCTION: Chest radiology provides an opportunity to better understand the diagnostic characteristics of e-cigarette or vaping product use associated lung injury (EVALI). This systematic review aimed to summarize the radiological findings associated with EVALI reported in the literature. METHODS: This systematic review was conducted in accordance with PRISMA guidelines. Electronic searches of MEDLINE®, CINAHL, Embase® and CENTRAL were conducted in February 2020. Included were all English-language studies reporting radiological findings of EVALI. Data was synthesized using descriptive statistics. RESULTS: Thirty studies comprising 184 participants were included. Mean patient age was 24.5 years old. The majority (n = 141, 76.6%) of included patients were male. The most common radiological features reported on chest x-ray were bilateral infiltrates (n = 64, 41.3%) and ground glass opacities (n = 17, 11.0%), and on chest CT were bilateral infiltrates (n = 62, 36.9%), bilateral ground glass opacities (n = 56, 33.3%), subpleural sparing (n = 29, 17.3%), pleural effusions (n = 14, 8.3%), and centrilobular nodularity (n = 13, 7.7%). Of patients with follow-up data reported (n = 81), only 28.4% (n = 23) had complete resolution of symptoms or radiological findings. CONCLUSION: Chest radiology is the cornerstone of diagnosis and monitoring of EVALI. A wide variety of radiological findings highlight the need for standardisation of terminology in the radiological descriptions of EVALI. Common findings included bilateral infiltrates and ground glass opacities. Higher quality evidence is warranted to help develop evidenced-based guidelines for the diagnosis and management of EVALI.

90Y PET for Qualitative and Quantitative Assessment of Residual Activity in Delivery Apparatus After Radioembolization.

Assessment of residual activity is critical for quality assurance after 90Y radioembolization. The resin microsphere manufacturer's indirect method of estimating the residual activity is laborious and vulnerable to inaccuracies. Furthermore, the method cannot localize the exact site of residual activity. 90Y PET/CT for qualitative and quantitative assessment of residual activity has not, to our knowledge, been described. We show an example of 90Y PET/CT of residual activity in the delivery apparatus and catheters packed inside the delivery box. Focally intense residual activity was clearly localized to the stopcock junction. Residual activity was directly quantified by setting the PET volume-of-interest isocontour threshold to 1%.

Hip pathology: the diagnostic accuracy of magnetic resonance imaging.

BACKGROUND: Hip arthroscopy has led to a greater understanding of intra-articular hip pathology. Non-contrast magnetic resonance imaging (MRI) is currently the gold standard in non-invasive imaging diagnosis, with high sensitivity in identifying labral pathology but equivocal results for ligamentum teres damage and chondral defects. The aim of this study is to determine the accuracy of non-contrast MRI for diagnosis of intra-articular hip derangements and identify radiological features that could increase the accuracy of the diagnosis. METHODS: A prospective study of 71 hips on 68 patients undergoing hip arthroscopy was conducted comparing pre-operative analysis of MRI imaging versus an arthroscopic examination. Two musculoskeletal radiologists reported the data independently. All hip arthroscopies were performed by a single surgeon. Patients with MRIs performed within 6 months before hip arthroscopy were included. Outcome measures included observer accuracy identifying ligamentum teres tears, labral lesions, and chondral rim damage. Secondary outcome measures included inter-observer variability and correctly staged ligamentum teres tears. RESULTS: The accuracy of radiology reporting for ligamentum teres tears, labral damage, and chondral rim lesions was 85.92% for each instance. The MRI findings most consistent with labral tears include the presence of linear high signal traversing the articular surface into the labrum, presence of intra-labral fluid signal, and loss of homogenous low signal triangular morphology. Chondral rim damage was difficult to diagnose, but abnormal signal at the chondrolabral junction with partial thickness defects would suggest damage. Ligamentum teres tears are commonly found but poorly graded. Thickening and increased signal suggests synovitis while discontinuity and fraying suggests partial tearing. CONCLUSION: Conventional non-arthrographic MRI offers an accurate non-invasive method to screen patients with symptoms referable to the hip by revealing the presence of labral tears, chondral defects, and ligamentum teres tears/synovitis. This study demonstrates that tears and synovitis of the ligamentum teres as potential sources of hip pain can be accurately identified on conventional non-arthrographic MRI. However, MRI has poor specificity and negative predictive value, and thus, a negative MRI result may warrant further investigation.

Importance of mentoring in Australian radiology training.

Mentoring is widely accepted as a fundamental component of a number of professions; however, mentoring is underutilized, and its practice is poorly instituted in most Australian radiology training programmes. This article highlights the benefits of mentoring within the radiology training context. Potential barriers to successful mentoring are elucidated, and future pathways for improved implementation and application of mentor programmes with radiology training programmes are presented.