Validating the safety of low-dose CTPA in pregnancy: results from the OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) Study.

BACKGROUND: Pulmonary embolism (PE) is a leading cause of pregnancy-related mortality. CT pulmonary angiogram (CTPA) is the first-line advanced imaging modality for suspected PE in pregnancy at institutes offering low-dose techniques; however, a protocol balancing safety with low dose remains undefined. The wide range of CTPA doses reported in pregnancy suggests a lack of confidence in implementing low-dose techniques in this group. PURPOSE: To define and validate the safety, radiation dose and image quality of a low-dose CTPA protocol optimised for pregnancy. MATERIALS AND METHODS: The OPTICA study is a prospective observational study. Pregnant study participants with suspected PE underwent the same CTPA protocol between May 2018 and February 2022. The primary outcome, CTPA safety, was judged by the reference standard; the 3-month incidence of venous thromboembolism (VTE) in study participants with a negative index CTPA. Secondary outcomes defined radiation dose and image quality. Absorbed breast, maternal effective and fetal doses were estimated by Monte-Carlo simulation on gestation-matched phantoms. Image quality was assessed by signal-to-noise and contrast-to-noise ratios and a Likert score for pulmonary arterial enhancement. RESULTS: A total of 116 CTPAs were performed in 113 pregnant women of which 16 CTPAs were excluded. PE was diagnosed on 1 CTPA and out-ruled in 99. The incidence of recurrent symptomatic VTE was 0.0% (one-sided 95% CI, 2.66%) at follow-up. The mean absorbed breast dose was 2.9 ± 2.1mGy, uterine/fetal dose was 0.1 ± 0.2mGy and maternal effective dose was 1.4 ± 0.9mSv. Signal-to-noise ratio (SNR) was 11.9 ± 3.7. Contrast-to-noise ratio (CNR) was 10.4 ± 3.5. CONCLUSION: The OPTICA CTPA protocol safely excluded PE in pregnant women across all trimesters, with low fetal and maternal radiation. CLINICAL RELEVANCE: OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) is the first prospective study to define the achievable radiation dose, image-quality and safety of a low-dose CT pulmonary angiogram protocol optimised for pregnancy (NCT04179487). It provides the current benchmark for safe and achievable CT pulmonary angiogram doses in the pregnant population. KEY POINTS: • Despite the increased use of CT pulmonary angiogram in pregnancy, an optimised low-dose protocol has not been defined and reported doses in pregnancy continue to vary widely. • The OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) study prospectively defines the achievable dose, image quality and safety of a low-dose CT pulmonary angiogram protocol using widely available technology. • OPTICA provides a benchmark for safe and achievable CT pulmonary angiogram doses in the pregnant population.

Risk of persistent air leaks following percutaneous cryoablation and microwave ablation of peripheral lung tumors.

OBJECTIVES: To compare the incidence of persistent air leak (PAL) following cryoablation vs MWA of lung tumors when the ablation zone includes the pleura. METHODS: This bi-institutional retrospective cohort study evaluated consecutive peripheral lung tumors treated with cryoablation or MWA from 2006 to 2021. PAL was defined as an air leak for more than 24 h after chest tube placement or an enlarging postprocedural pneumothorax requiring chest tube placement. The pleural area included by the ablation zone was quantified on CT using semi-automated segmentation. PAL incidence was compared between ablation modalities and a parsimonious multivariable model was developed to assess the odds of PAL using generalized estimating equations and purposeful selection of predefined covariates. Time-to-local tumor progression (LTP) was compared between ablation modalities using Fine-Gray models, with death as a competing risk. RESULTS: In total, 260 tumors (mean diameter, 13.1 mm ± 7.4; mean distance to pleura, 3.6 mm ± 5.2) in 116 patients (mean age, 61.1 years ± 15.3; 60 women) and 173 sessions (112 cryoablations, 61 MWA) were included. PAL occurred after 25/173 (15%) sessions. The incidence was significantly lower following cryoablation compared to MWA (10 [9%] vs 15 [25%]; p = .006). The odds of PAL adjusted for the number of treated tumors per session were 67% lower following cryoablation (odds ratio = 0.33 [95% CI, 0.14-0.82]; p = .02) vs MWA. There was no significant difference in time-to-LTP between ablation modalities (p = .36). CONCLUSIONS: Cryoablation of peripheral lung tumors bears a lower risk of PAL compared to MWA when the ablation zone includes the pleura, without adversely affecting time-to-LTP. KEY POINTS: • The incidence of persistent air leaks after percutaneous ablation of peripheral lung tumors was lower following cryoablation compared to microwave ablation (9% vs 25%; p = .006). • The mean chest tube dwell time was 54% shorter following cryoablation compared to MWA (p = .04). • Local tumor progression did not differ between lung tumors treated with percutaneous cryoablation compared to microwave ablation (p = .36).

Chronic Pulmonary Manifestations of COVID-19 Infection: Imaging Evaluation.

This case presents a patient with severe COVID-19 pneumonia requiring intensive care unit admission and a prolonged hospital stay. The infection resulted in long-term morbidity, functional decline, and abnormal chest CT findings. The mechanisms for long-term lung injury after COVID-19 infection, imaging appearances, and the role of imaging in follow-up are discussed.

Safety and Effectiveness of Percutaneous Image-Guided Thermal Ablation of Juxtacardiac Lung Tumors.

PURPOSE: To evaluate the safety and effectiveness of percutaneous image-guided thermal ablation (IGTA) for juxtacardiac lung tumors. MATERIALS AND METHODS: This bi-institutional retrospective cohort study included 23 consecutive patients (13 [57%] male; mean age, 55 years ± 18) with 30 juxtacardiac lung tumors located ≤10 mm from the pericardium treated in 28 IGTA sessions (25 sessions of cryoablation and 3 sessions of microwave ablation) between April 2008 and August 2022. The primary outcome was any adverse cardiac event within 90 days after ablation. Secondary outcomes included noncardiac adverse events, local tumor progression-free survival (LT-PFS), and the cumulative incidence of local tumor progression with death as a competing risk. Two tumors treated without curative intent or follow-up imaging were considered in the safety analysis but not in the progression analysis. RESULTS: The median imaging follow-up duration was 22 months (interquartile range [IQR], 10-53 months). Primary technical success was achieved in 25 (89%) ablations. No adverse cardiac events attributable to IGTA occurred. One patient experienced a phrenic nerve injury. The median LT-PFS duration was 59 months (IQR, 32-73 months). At 1, 3, and 5 years, LT-PFS was 90% (95% CI, 78%-100%), 74% (CI, 53%-100%), and 45% (CI, 20%-97%), respectively, and the cumulative incidence of local tumor progression was 4.3% (CI, 0.29%-19%), 11% (CI, 1.6%-30%), and 26% (CI, 3.3%-58%), respectively. CONCLUSIONS: IGTA is safe and effective for lung tumors located ≤10 mm from the pericardium. No adverse cardiac events were not observed within 90 days after ablation.

MRA-detected intracranial atherosclerotic disease in patients with TIA and minor stroke.

OBJECTIVES: Patients with TIA and minor stroke commonly undergo CT and CTA in the emergency department with subsequent MRI with MRA for further workup. The purpose of this study was to review outpatient MRIs for TIA/stroke patients to assess the additional benefit, if any, of the MRA sequence in the detection of intracranial atherosclerotic disease in patients for whom CTA had already been performed. METHODS: The radiology reports of outpatient MRIs of the brain for TIA/minor stroke patients were retrospectively reviewed via the hospital PACS system. Following this, the imaging report from the patient's initial presentation to the emergency department was reviewed. This index imaging and subsequent MRI were compared to assess the incidence of new vascular findings detected on the MRA sequence in patients for whom CTA had already been performed. Where new lesions had been identified at follow-up, the imaging was retroactively reviewed to assess if they were present on the index imaging. RESULTS: Two hundred seven consecutive patients were reviewed. Significant (> 50%) intracranial atherosclerotic disease was present on MRA in 18 patients (8.7%). This was a new finding in 11 patients. Five had initial CTA where the atherosclerosis was not detected. All 5 of these cases were located in the posterior cerebral arteries. Incidental aneurysms were seen in 14 (6.7%); 12 were a new finding at time of MRI. CONCLUSION: The MRA sequence provides additional value by increasing the detection of clinically important intracranial atherosclerotic disease which may inform management in patients with minor stroke and TIA.

Breast Shielding Combined With an Optimized Computed Tomography Pulmonary Angiography Pregnancy Protocol: A Special Use-Case for Shielding?

OBJECTIVES: To determine the impact of breast shields on breast dose and image quality when combined with a low-dose computed tomography pulmonary angiography (CTPA) protocol for pregnancy. METHODS: A low-dose CTPA protocol, with and without breast shields, was evaluated by anthropomorphic phantom and 20 prospectively recruited pregnant participants from January to October 2019. Thermoluminescent dosimeters measured surface and absorbed breast dose in the phantom and surface breast dose in participants. The Monte-Carlo method estimated the absorbed breast dose in participants. Image quality was assessed quantitatively by regions of interest analysis and subjectively by the Likert scale. Doses and image quality for CTPA alone were compared with CTPA with breast shields. RESULTS: Mean surface and absorbed breast dose for CTPA alone were 1.3±0.4 and 2.8±1.5 mGy in participants, and 1.5±0.7 and 1.6±0.6 mGy in the phantom. Shielding reduced surface breast dose to 0.5±0.3 and 0.7±0.2 mGy in the phantom (66%) and study participants (48%), respectively. Absorbed breast dose reduced to 0.9±0.5 mGy (46%) in the phantom.Noise increased with breast shields at lower kV settings (80 to 100 kV) in the phantom; however, in study participants there was no significant difference between shield and no-shield groups for main pulmonary artery noise (no-shield: 34±9.8, shield: 36.3±7.2, P =0.56), SNR (no-shield: 11.2±3.7, shield: 10.8±2.6, P =0.74) or contrast-to-noise ratio (no-shield: 10.0±3.3, shield: 9.3±2.4, P =0.6). Median subjective image quality scores were comparable (no-shield: 4.0, interquartile range: 3.5 to 4.4, shield: 4.3, interquartile range: 4.0 to 4.5). CONCLUSION: Combining low-dose CTPA with breast shields confers additional breast-dose savings without impacting image quality and yields breast doses approaching those of low-dose scintigraphy, suggesting breast shields play a role in protocol optimization for select groups.

Diagnosis and Treatment of Lung Cancer in the Setting of Interstitial Lung Disease.

Interstitial lung disease (ILD) including idiopathic pulmonary fibrosis increases the risk of developing lung cancer. Diagnosing and staging lung cancer in patients with ILD is challenging and requires careful interpretation of computed tomography (CT) and fluorodeoxyglucose PET/CT to distinguish nodules from areas of fibrosis. Minimally invasive tissue sampling is preferred but may be technically challenging given tumor location, coexistent fibrosis, and pneumothorax risk. Current treatment options include surgery, radiation therapy, percutaneous thermal ablation, and systemic therapy; however, ILD increases the risks associated with each treatment option, especially acute ILD exacerbation.

Magnetic Resonance Imaging for Guidance and Follow-up of Thoracic Needle Biopsies and Thermal Ablations.

Magnetic resonance imaging (MRI) is used for the guidance and follow-up of percutaneous minimally invasive interventions in many body parts. In the thorax, computed tomography (CT) is currently the most used imaging modality for the guidance and follow-up of needle biopsies and thermal ablations. Compared with CT, MRI provides excellent soft tissue contrast, lacks ionizing radiation, and allows functional imaging. The role of MRI is limited in the thorax due to the low hydrogen proton density and many air-tissue interfaces of the lung, as well as respiratory and cardiac motion. Here, we review the current experience of MR-guided thoracic needle biopsies and of MR-guided thermal ablations targeting lesions in the lung, mediastinum, and the chest wall. We provide an overview of MR-compatible biopsy needles and ablation devices. We detail relevant MRI sequences and their relative advantages and disadvantages for procedural guidance, assessment of complications, and long-term follow-up. We compare the advantages and disadvantages of CT and MR for thoracic interventions and identify areas in need of improvement and additional research.

Update on Image-Guided Thermal Lung Ablation: Society Guidelines, Therapeutic Alternatives, and Postablation Imaging Findings.

Percutaneous image-guided thermal ablation (IGTA) has been endorsed by multiple societies as a safe and effective lung-preserving treatment of primary lung cancer and metastases involving the lung and chest wall. This article reviews the role of IGTA in the care continuum of patients with thoracic neoplasms and discusses strategies to identify the optimal local therapy considering patient and tumor characteristics. The advantages and disadvantages of percutaneous thermal ablation compared with surgical resection and stereotactic body radiotherapy are summarized. Principles of radiofrequency ablation, microwave ablation, and cryoablation, as well as the emerging use of transbronchial thermal ablation, are described. Specific considerations are presented regarding the role of thermal ablation for early-stage non-small cell lung cancer (NSCLC), multifocal primary NSCLC, pulmonary metastases, salvage of recurrent NSCLC after surgery or radiation, and pain palliation for tumors involving the chest wall. Recent changes to professional society guidelines regarding the role of thermal ablation in the lung, including for treatment of oligometastatic disease, are highlighted. Finally, recommendations are provided for imaging follow-up after thermal ablation of lung tumors, accompanied by examples of expected postoperative findings and patterns of disease recurrence.

Increased incidence of acute calculous cholecystitis observed during COVID-19 social restrictions.

PURPOSE: In response to the outbreak of COVID-19 in Ireland, the government implemented a nationwide stay-at-home order, with the closure of all non-essential businesses. During this period, there was a significant increase in supermarket expenditure. It has been shown that stress, anxiety and boredom are triggers for unhealthy eating habits. Fat consumption is a risk factor for both the development of gallstones and, additionally, the development of acute calculous cholecystitis. The aim of this study was to assess the incidence of acute calculous cholecystitis during the nationwide lockdown and compare it to the same period one year prior. METHODS: A retrospective review of all emergency abdominal imaging performed during the first 5 weeks of the lockdown was completed using the hospital PACS (picture archiving and communication system). All cases of acute calculous cholecystitis were identified and compared with the same period 1 year prior. RESULTS: Eighteen cases of acute calculous cholecystitis were identified from 24 March to 27 April 2020. Eleven cases were identified during the same period in 2019. This represented an increase of 63%. Non-COVID-19-related emergency presentations decreased during this period, and imaging of emergency presentations decreased by 24%. The rate of scans positive for acute cholecystitis more than doubled (p < 0.037). CONCLUSION: A statistically significant increase in cases of acute calculous cholecystitis was observed during a nationwide lockdown during the COVID-19 pandemic. It is hypothesised that this is due to increased consumption of fatty foods during this period due to stress, anxiety and boredom.

Comparison of Percutaneous Image-Guided Microwave Ablation and Cryoablation for Sarcoma Lung Metastases: A 10-Year Experience.

BACKGROUND. To our knowledge, outcomes between percutaneous microwave ablation (MWA) and cryoablation of sarcoma lung metastases have not been compared. OBJECTIVE. The purpose of this study was to compare technical success, complications, local tumor control, and overall survival (OS) after MWA versus cryoablation of sarcoma lung metastases. METHODS. This retrospective cohort study included 27 patients (16 women, 11 men; median age, 64 years; Eastern Cooperative Oncology Group performance score, 0-2) who, from 2009 to 2021, underwent 39 percutaneous CT-guided ablation sessions (21 MWA and 18 cryoablation sessions; one to four sessions per patient) to treat 65 sarcoma lung metastases (median number of tumors per patient, one [range, one to 12]; median tumor diameter, 11.0 mm [range, 5-33 mm]; 25% of tumors were nonperipheral). We compared complications according to ablation modality by use of generalized estimating equations. We evaluated ablation modality, tumor size, and location (peripheral vs nonperipheral) in relation to local tumor progression by use of proportional Cox hazard models, with death as the competing risk. We estimated OS using the Kaplan-Meier method. RESULTS. Primary technical success was 97% for both modalities. Median follow-up was 23 months (range, one to 102 months; interquartile range, 12-44 months). A total of seven of 61 tumors (11%) showed local progression. Estimated 1-year and 2-year local control rates were, for tumors 1 cm or smaller, 97% and 95% after MWA versus 99% and 98% after cryoablation, and for tumors larger than 1 cm, 74% and 62% after MWA versus 86% and 79% after cryoablation. Tumor size of 1 cm or smaller was associated with a decreased cumulative incidence of local progression (p = .048); ablation modality and tumor location were not associated with progression (p = .86 and p = .54, respectively). Complications (Common Terminology Criteria for Adverse Events [CTCAE] grade, ≤ 3) occurred in 17 of 39 sessions (44%), prompting chest tube placement in nine (23%). There were no CTCAE grade 4 or 5 complications. OS at 1, 2, and 3 years was 100%, 89%, and 82%, respectively. CONCLUSION. High primary technical success, local control, and OS support the use of MWA and cryoablation for treating sarcoma lung metastases. Ablation modality and tumor location did not affect local progression. The rate of local tumor progression was low, especially for small tumors. No life-threatening complications occurred. CLINICAL IMPACT. Percutaneous MWA and cryoablation are both suited for the treatment of sarcoma lung metastases, especially for tumors 1 cm or smaller, whether peripheral or nonperipheral. Complications, if they occur, are not life-threatening.

Multimodal imaging of Spina Ventosa (TB Dactylitis) of the foot.

We present the case of a 29-year-old male healthcare worker with a 6 month history of progressive left foot pain resulting in presentation to the emergency department on 3 occasions. He denied systemic symptoms. Multimodal imaging demonstrated an expansile erosive inflammatory lesion centered on the neck of the second metatarsal with aggressive features. CT of the thorax, abdomen, and pelvis demonstrated calcified mediastinal lymph nodes and left inguinal adenopathy. The lesion was biopsied under ultrasound guidance demonstrating a necrotizing granulomatous osteomyelitis with acid fact bacilli. This is consistent with TB dactylitis (spina ventosa). Treatment with antimycobacterial drugs was commenced.

Can the synthetic C view images be used in isolation for diagnosing breast malignancy without reviewing the entire digital breast tomosynthesis data set?

AIMS AND OBJECTIVES: The aim of this study was to determine if the synthetic C view acquired at digital breast tomosynthesis (DBT) would give adequate information to confirm a malignancy and could obviate the need to review all the tomosynthesis image data set. METHODS: All patients with biopsy-proven breast cancer recalled from screening mammograms between May and September 2016 were included for review. For each patient, the screening 2D mammogram, the synthetic C view, and the DBT images were reviewed by three breast radiologists and each assigned a BIRADS code. Any discrepancies were reviewed and resolved by consensus. RESULTS: A total of 92 patients were diagnosed with breast cancer in this time period. Fourteen were excluded because they did not have DBT performed. Five women were recalled for evaluation of two lesions. In total, 83 lesions were assessed. In 27 cases, the BIRADS code remained unchanged in the three modalities. In 16 cases, the lesions appeared more concerning on C view and DBT that on the original mammogram but were not definitive for malignancy (BIRADS 4). In 29 cases, a BIRADS 5 code was assigned on C view and tomosynthesis but not on 2D. For 11 lesions, a BIRADS 5 code was assigned only on DBT. Four women had BIRADS 5 lesions seen on both the C view and DBT that were not seen on the screening 2D mammogram. One was multifocal. CONCLUSION: While the synthetic C view gives additional information when compared to a screening 2D mammogram, the full DBT tomosynthesis data set needs to be reviewed to diagnose a breast malignancy.