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.

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.

Pernicious azotaemia? A case series of subacute combined degeneration of the cord secondary to nitrous oxide abuse.

Nitrous oxide abuse is a rare cause of vitamin B12 deficiency and consequent subacute combined degeneration of the spinal cord. Worldwide and Australian statistics indicate that recreational use of nitrous oxide is increasing. We report four cases of females aged 18-24 years presenting with clinical symptoms of subacute combined degeneration of the spinal cord. MRI during admission demonstrated the classic findings of T2 hyperintensity, predominantly within the dorsal columns of the spinal cord, with variable involvement of the lateral corticospinal tracts. These cases highlight the ready availability of nitrous oxide and the fact that heavy prolonged recreational use is occurring in the community. It is important that clinicians in emergency and community settings are alerted to this unusual cause of subacute combined degeneration of the spinal cord because early aggressive vitamin B12 replacement together with behavioural change can reverse this disabling neurological syndrome.

Opercular perivascular cysts: A proposed new subtype of dilated perivascular spaces.

PURPOSE: Dilated perivascular spaces are a common finding on brain MRI, traditionally classified into three types based on location and relationship to vessels. Recent studies have characterised an additional variant of dilated perivascular spaces that arise within the anterior temporal lobe and have unique neuroimaging features. These particular perivascular spaces are associated with a vascular loop of a branch of the middle cerebral artery (MCA) and commonly demonstrate perilesional T2/FLAIR signal. To our knowledge, these have not previously been described in the frontal lobe. METHOD: Dilated perivascular spaces associated with a vascular loop of a branch of the middle cerebral artery (MCA) identified at our institution were reviewed for imaging characteristics and anatomical location. RESULTS: 18 cases were identified. 16 were located in the anterior temporal lobe and two were located in the frontal operculum. All demonstrated internal signal characteristics identical to CSF on all sequences, with no contrast enhancement or susceptibility artefact and variable perilesional T2/FLAIR signal. CONCLUSIONS: We report further evidence of a distinct subtype of dilated perivascular spaces occurring in the anterior temporal lobe in association with a vascular loop of a branch of the MCA. In addition, we have demonstrated that these may also occur in the frontal operculum. We therefore suggest that these dilated perivascular spaces of the operculum be recognised as a separate, fourth, subtype of perivascular space and propose the term "opercular perivascular cyst".

Extraosseous Ewing sarcoma arising in a chronically lymphedematous limb.

Ewing sarcoma is a highly aggressive small round cell malignant neoplasm of bone and soft tissue that typically is manifested in children and young adults. It is most commonly a primary bone tumor; however, extraosseous cases have been increasingly reported. We report a case of metastatic extraosseous Ewing sarcoma with the primary lesion occurring within a limb affected by primary lymphedema. Lymphedema, in this case, played a role not only in the genesis of the tumor because of the relative local immunosuppression but also in masking the development of the lower limb mass.

Rare "Inverted" Verrucous Carcinoma (Carcinoma Cuniculatum) of the Sacrogluteal Region: Case Report and Literature Review.

A 49-year-old woman with a past history of several infundibular cysts in the head and neck region presented with a 6-month history of a nonhealing perianal abscess on a background of 13 years of chronic sacral-buttock abscesses and discharging sinuses as part of hidradenitis suppurativa. After 2 surgical procedures and inadequate healing, a wide local excision was performed. The surgical specimen revealed an extensive, infiltrating, cystic and deeply penetrating, dermal and subcutaneous neoplasm with multiple fistulous tracts extending to the skin surface. The histopathology was consistent with carcinoma cuniculatum, a rare, slow growing, verucciform variant of squamous cell carcinoma. An entirely subcutaneous verrucous carcinoma of the sacrogluteal region is exceptionally rare, and this represents the first documentation of such a case in a female.