Katie Robinson

In a recent multinational study involving over 1,600 patients presenting with proximal anterior circulation occlusion stroke in the extended window, researchers found that the use of non-contrast computed tomography (CT) to determine candidacy for mechanical thrombectomy had similar clinical and safety outcomes in comparison to CT perfusion or magnetic resonance imaging (MRI).

“To our knowledge, this is the largest multicenter study to date assessing selection of patients in the extended time window with non-contrast CT compared with CT perfusion or MRI,” wrote Thanh N. Nguyen, MD, the director of interventional neurology/neuroradiology at Boston Medical Center and a professor of neurology, neurosurgery, and radiology at the Boston University School of Medicine. “These findings suggest non-contrast computed tomography alone may be used as an alternative to advanced imaging in selecting patients with late-presenting large-vessel occlusion for mechanical thrombectomy.”

Advanced imaging with MRI or CT perfusion is currently recommended in the American Stroke Association and European Stroke Organization guidelines for the selection of patients with large-vessel occlusion stroke who present within six to 24 hours from symptom onset. However, access to acute MRI or CT perfusion is not readily available or performed in many stroke centers.

This multinational cohort study, published in 

, included 1,604 consecutive patients (median age of 70) with proximal anterior circulation occlusion stroke who presented within six to 24 hours of the last time they were seen well. Patients presented from January 2014 to December 2020 and were followed for 90 days from stroke onset. The researchers compared the clinical and safety outcomes of 534 patients selected for mechanical thrombectomy by non-contrast CT with 752 patients selected by CT perfusion and 318 patients selected by MRI in the extended time window.

The study authors found no difference in the 90-day ordinal modified Rankin Scale (mRS) shift between patients selected by CT compared with CT perfusion (adjusted odds ratio (aOR), 0.95 [95% CI, 0.77-1.17]; 

 = .64) or CT versus MRI (aOR, 0.95 [95% CI, 0.8-1.13]; 

 = .55). For the secondary outcomes, the rates of 90-day functional independence were similar between patients selected by CT and CT perfusion, but lower in patients selected by MRI than CT. Successful reperfusion was more common in the CT and CT perfusion groups (88.9 percent and 89.5 percent respectively) compared with the MRI group at 78.9 percent. No significant differences in symptomatic intracranial hemorrhage or 90-day mortality were observed, according to the study.

“These findings have the potential to widen the indication for treating patients in the extended window using a simpler and more widespread non-contrast CT–only paradigm,” the authors wrote.

The authors noted that since the study was limited to patients with baseline mRS scores of 0 to 2 and occlusion of the internal carotid or proximal middle cerebral artery, the findings cannot be extrapolated to other patients. Other reported limitations of the study included the retrospective design and not using an independent imaging core laboratory, factors that may have led to patient selection bias.

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Study findings suggest that assessment with the simpler and more commonly available non-contrast computed tomography (CT) may widen the indication for treating patients in the extended window. 

Is Non-contrast CT a Viable Option for Assessing Patients with Late Stroke Presentation for Mechanical Thrombectomy?

In patients with large vessel occlusion not treated with reperfusion therapies, researchers have noted a common symmetric collateral pattern via computed tomography (CT) angiography, according to a study recently published in 

 Moreover, this pattern was highly specific for low ischemic core growth rate and small 24-hour 

 as assessed at diffusion-weighted magnetic resonance imaging (MRI). 

“Understanding ischemic core growth rate is key in identifying patients with slow-progressing large vessel occlusion stroke who may benefit from delayed endovascular thrombectomy,” wrote Aneesh B. Singhal, M.D., vice-chair of the Department of Neurology at Massachusetts General Hospital in Boston, and colleagues. “After further outcome studies, collateral status at presentation may prove useful in triage for endovascular thrombectomy, especially when MRI and CT perfusion are unavailable.”

In this retrospective study, researchers evaluated clinical trial data from January 2007 to June 2009, prior to the emergence of endovascular thrombectomy as the standard of care. The secondary analysis included 31 patients (median age of 71 years) with anterior proximal large vessel occlusion stroke not treated with reperfusion therapies. Patients underwent admission CT angiography and at least three MRI examinations at four time points over 48 hours. At presentation, the arterial phase CT angiography collaterals were categorized as symmetric, malignant or other. Diffusion-weighted MRI ischemic core volume and ischemic core growth rate were determined at multiple time points.

The median ischemic core volume and growth rate were significantly different in comparing collateral patterns at CT angiography at nearly all time points. At diffusion-weighted MRI, median 24-hour ischemic core volumes were 28 cm

 (malignant). Symmetric collateral pattern at CT angiography was common at 45%, with high sensitivity and specificity, at 87% and 94%, respectively, or 24-hour ischemic core volume less than 50 cm

“Our data set characterized the natural history of ischemic core growth in the setting of large vessel occlusion over 48 hours,” the authors wrote. “Comparison of collateral patterns showed that there were different ischemic core volumes and ischemic core growth rates at multiple points.”

The study authors conceded limitations of the study, including a small sample size and single center design, which could limit generalizability.

 Steven A. Messina, M.D. noted that multivariable analyses of this research demonstrated independent associations between severe National Institutes of Health Stroke Scale scores and worse collateral pattern at presentation with greater ischemic core volume and growth rate.

“These data alone indicate that there are potentially more patients who may benefit from endovascular thrombectomy whom we are not identifying currently, and therefore a more thorough investigation is needed beyond the 24-hour mark,” wrote Dr. Messina, an assistant professor of radiology at the Mayo Clinic in Rochester, Minnesota.

Dr. Messina emphasized arterial collaterals as a key factor when assessing patients with large vessel occlusion.

“This work provides further evidence of the crucial role of arterial collaterals regarding infarct evolution in patients who present with large vessel occlusion, with intriguing data extending beyond the 24-hour point.” Dr. Messina wrote. “Importantly, these data highlight that it is necessary for radiologists to continue to add needed value regarding collateral status to CT angiography interpretations in these patients.”

New research emphasizes roles of anterior collaterals and ischemic core growth rate in assessing patients with large vessel occlusion. 

Collateral Pattern on CT Angiography May Help Identify Candidates for Delayed Endovascular Thrombectomy

In patients with refractory B-cell lymphoma, thoracic imaging findings correlated with cytokine release syndrome grade following chimeric antigen receptor (CAR) T-cell infusion. This is according to a study published in

 which also showed that CAR T-cell therapy yielded high rates of imaging-based treatment response.

“Imaging plays a critical role in the evaluation of clinical cytokine release syndrome and immune effector cell–associated neurotoxicity syndrome (ICANS) toxicity following CAR T-cell treatment,” wrote Daniel Smith, M.D., a radiologist at the University Hospitals Cleveland Medical Center in Ohio. “Specific findings at thoracic imaging—in particular, pleural effusion and atelectasis—may prove useful correlates for severe clinical grades of cytokine release syndrome, while findings related to ICANS tend to be less specific and less frequent. “

CAR T-cell immunotherapy is increasingly used for refractory lymphoma, but it may lead to cytokine release syndrome and ICANS in the early period following infusion. The associations between cytokine release syndrome or ICANS grade and imaging findings are not established. The goal of this study was to characterize thoracic and neuroimaging findings associated with cytokine release syndrome and ICANS in patients with refractory B-cell lymphoma.

The retrospective analysis included 38 patients (mean age 59; 61% men) with refractory B-cell lymphoma who underwent CAR T-cell infusion. Of these, 63% and 29% experienced clinical grade 1 or higher cytokine release syndrome and ICANS, respectively. Patients with grade 2 or higher cytokine release syndrome were more likely to have thoracic imaging evidence — at radiography, CT and/or MRI — of pleural effusions (36% vs 8.3%, P = .04) and atelectasis (57% vs 25%, P = .048) than patients without cytokine release syndrome or with grade 1 toxicity. Positive imaging findings were identified in 43% with grade 2 or higher ICANS who underwent neuroimaging. Patients undergoing CAR T-cell therapy had higher rates of clinical response, including 56% with complete response and 19%with partial response.

“Our findings further highlight the central role of PET/CT in disease response after CAR-T cell therapy,” the authors wrote.

Limitations of the study included its retrospective design, small sample size, and that most patients without toxicity did not undergo imaging.

 Mark Langer, M.D., professor of clinical radiation oncology at Indiana University School of Medicine, wrote that “in the study by Smith et al, atelectasis and pleural effusions were more common in patients with severe cytokine release syndrome than in those with mild or absent cases. Edema and airway consolidation were not more common.” He added, “Whether such features emerge only when the case becomes clinically more severe or whether these features are early signs of disease that will eventually evolve into a higher-grade condition is a question deserving of future study.

“As more data are prospectively obtained, imaging guidelines to better monitor for the important conditions examined here may be established, and the information collected used to effectively intervene early in detection and treatment,” Dr. Langer wrote.

Study findings further highlight the central role of PET/CT in disease response after CAR-T cell therapy. 

Imaging Findings May Help Detect CAR T-Cell Therapy Toxicities

Low-field magnetic resonance imaging (MRI) offers comparable performance to routine computerized tomography (CT) and MRI for following hydrocephalus. This is according to initial results from an ongoing trial presented at the 

Radiological Society of North America (RSNA) 2021 Annual Meeting

, which also found that deep-learning based lateral ventricle volume estimates from low-field MRI are accurate.

“Patients with hydrocephalus require repeated neuroimaging to monitor ventricular volumes and avoid complications,” the authors wrote. “Low-field MRI may offer a cost-effective, radiation-free alternative to monitor ventricular volume changes in patients with hydrocephalus.”

The results were presented by Thomas Campbell Arnold, DPhil, department of bioengineering at the University of Pennsylvania in Philadelphia.

Standard of care imaging for patients with hydrocephalus includes routine CT or MRI. However, CT uses ionizing radiation and provides less soft-tissue contrast and MRI is more expensive, less widely available and is subject to imaging artifacts from commonly used programmable ventricular shunts. Further, strong magnetic fields change programmable shunt settings.

“We hypothesized that low-field imaging would provide a comparable and more convenient point-of-care assessment for alterations in ventricle size, less shunt-related artifact and less need for programmable shunt checks,” the authors wrote.

In this ongoing study, the researchers assessed a recent US FDA cleared, portable, low-field strength (64mT) MRI scanner (Hyperfine, Guilford, Connecticut) that was used to monitor 22 patients with known or suspected hydrocephalus. Same-day low-field MRI and standard of care imaging, with CT or MRI, were collected for each patient. A neuroradiologist assessed ventricles as abnormally increased, decreased or within expected limits. Additionally, semi-automated ventricular volume segmentations were generated for clinical MRI scans and compared with deep-learning based volumes that were provided automatically by the low-field device.

Radiological assessments were comparable between low-field MRI and standard of care imaging. One patient presented with a shunt related hemorrhage on both imaging modalities. A strong correlation (R=0.97, p<0.001) was found between lateral ventricle volume measurements on low-field and clinical MRI.

Settings for programmable shunts, which were present in 10 patients, were recorded before and after low-field imaging. Shunt settings were altered in nine of these cases.

“Programmable shunts must still be checked by the clinical care team after low-field imaging,” the authors wrote.

Early study results suggest that low-field MRI may offer a cost-effective, radiation-free alternative to monitor ventricular volume changes in patients with hydrocephalus. 

Low-field MRI Matches Standard-Of-Care Imaging for Hydrocephalus

 describes a community-based outreach intervention that was effective at identifying and addressing barriers to lung cancer screening, such as cost, lower literacy levels and fear of diagnosis.

“Radiologists can partner with patients and key community stakeholders in the development of effective lung cancer screening outreach interventions aimed to increase equitable lung cancer screening participation among low socioeconomic status communities,” the authors wrote.

The results were presented by Efren Jesus Flores, M.D., department of radiology at Massachusetts General Hospital, in Boston.

Community-based lung cancer screening outreach can help individuals from low socioeconomic status communities, who experience worse lung cancer outcomes, by addressing barriers to digital health and promoting trust. In this study, the researchers aimed to develop a tailored digital health outreach intervention to promote lung cancer screening and understand related social needs among low socioeconomic status communities.

Focus groups were conducted at an urban academic medical center with affiliated community health centers with 12 representative primary care physicians, eight advocates, seven lung cancer screening patients and eight non- lung cancer screening patients. Three tailored lung cancer screening outreach video conditions were developed with messaging by a radiologist, patient and patient/radiologist together. 

A national sample of 315 current smokers with Medicaid who were eligible for lung cancer screening were randomized to watch one of the three video messages to determine satisfaction, preferred source, intent to screen and attitudes about lung cancer.

The focus groups cited transportation and fear about lung cancer as major barriers to screening. Patients reported confusion about screening eligibility criteria, the screening process and insurance coverage. The outreach video was modified to emphasize the treatability of early lung cancer, adopted clear language for eligibility and insurance coverage, and displayed a patient undergoing lung cancer screening and receiving results. 

Of the 315 participants, 67% reported satisfaction with the video, with those watching the video messaging from the patient reporting the greatest intent to speak to a physician about lung cancer screening. Participants reported limited social needs.

“Greater social need was associated with significantly lower health literacy, smoking-related stigma, lower confidence in arranging transport to lung cancer screening, greater cost concerns about screening, perceived severity of lung cancer and greater worry about developing lung cancer,” the authors wrote.

Cost, lower literacy levels and fear of lung cancer diagnosis were highlighted as concerns with lung cancer screening. 

Community-Based Intervention May Increase Lung Cancer Screening 

 suggest that diffusion-weighted imaging was a sensitive and effective screening method for breast cancer detection in asymptomatic women with dense breasts. 

“Mammography has low sensitivity in dense breasts and needs to be supplemented with another screening method for women with dense breasts,” the authors wrote. “Diffusion-weighted imaging may be useful as a safe and effective screening tool for the supplementation of mammography in women with dense breast tissues.”

The results were presented by Hee Jeong Kim, M.D., breast cancer center at Asan Medical Center in Seoul, Korea.

In the study, the researchers assessed the diagnostic performance of diffusion-weighted imaging for breast cancer detection in asymptomatic women with dense breast tissue on mammography. The researchers also compared the diagnostic performance of mammography, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging.

From August 2018 to January 2019, the researchers retrospectively reviewed 297 consecutive asymptomatic women, mean age of 51 years, with dense breast tissue on mammography who underwent breast MRI including diffusion-weighted imaging and DCE protocols and mammography. Three readers independently reviewed the lesion visibility and level of suspicion on each imaging modality. Histopathologic features of the tumors on surgical specimen served as the standard of reference.

A total of 233 breast cancers were identified in 230 women, benign lesions were identified in 11 women and normal breasts were identified in 56 women. Of the 233 cancers, 15% presented as ductal carcinoma in situ, 12% as microinvasive ductal carcinoma and 73% as invasive carcinoma. The overall sensitivity was 61.4% in mammography, 79.4% in diffusion-weighted imaging, 86.3% in DCE-MRI and 91.8% in the combination of mammography and diffusion-weighted imaging. The sensitivities for noninvasive cancer in mammography, diffusion-weighted imaging, DCE-MRI, and the combination of mammography and diffusion-weighted imaging were 73%, 68.3%, 74.6% and 92.1%, while the sensitivities for invasive cancer smaller than 20 mm were 51.9%, 81.5%, 88.9% and 89.6%, and the sensitivities for invasive cancer larger than 20 mm were 77.1%, 91.4%, 97.1% and 100%, respectively. 

When diagnostic performance was assessed by using areas under the receiver operating characteristic curves, diffusion-weighted imaging was superior to mammography (

 < .001) and comparable to DCE-MRI when combined with mammography (

Diffusion-weighted imaging may be useful as a safe and effective screening tool to supplement mammography in women with dense breast tissues. 

Diffusion-Weighted Imaging Helps Detect Breast Cancer in Dense Breasts 

 found that racial ethnic minorities, and patients with low socioeconomic status, lower access to broadband internet or limited English proficiency were less likely to use a patient-portal self-scheduling pathway for screening mammograms.

“Understanding the factors associated with patient use of technology and patient portals for access to care can guide interventions to bridge the existing digital divide and promote health equity in radiology,” the authors wrote.

The results were presented by Patricia Balthazar, M.D., assistant professor of abdominal radiology and imaging informatics at Emory University in Atlanta, Georgia.

While patient portals can increase patient access and engagement, they can create potential barriers to care. In this study, the researchers aimed to identify potential sociodemographic disparities in the use of an online patient portal to self-schedule screening mammograms compared with traditional scheduling pathway, such as a scheduler phone call and referral system. The researchers hypothesized that patients with limited English proficiency or low socioeconomic status, along with racial/ethnic minorities would be less likely to use the online self-scheduling pathway.

This retrospective cohort study included 46,268 female patients undergoing screening mammograms from Jan. 1, 2019, to Dec. 31, 2019, at an urban quaternary-care academic medical center. The following data were extracted: patient scheduling pathway, age, language, race, health insurance provider and zip code, with the latter linked to Census data to extract the following demographic information: internet access, median household income and education level.

Of the patients, 0.7% used the online self-scheduling pathway. Those using the self-scheduling pathway had higher odds of being younger (OR for age in year: 0.94; 95% CI: 0.93-0.96), English-speakers (95% CI: 21.6, 3.0-156.5), White (95% CI: 1.7, 1.2-2.5), have private insurance (95% CI: 1.5, 1.0-2.1) and to live in zip code areas with higher percentage of access to broadband internet (95% CI: 1.2, 1.1-1.3).

Unlike racial ethnic minorities, patients with low socioeconomic status, lower access to broadband internet and limited English proficiency, “patients living in zip code areas with higher median household income, education level or with any type of internet access were not significantly associated with the online self-scheduling pathway,” the authors wrote.

This study discloses the characteristics of patients using self-scheduled online patient portal screening mammography. 

Online Patient Portals for Screening Mammograms May Widen Health Disparities 

68Ga prostate specific membrane antigen (PSMA) positron emission tomography (PET) has high utility in the detection of suspicious lesions in biochemically recurrent prostate cancer. This is according to study results presented at the 

“PSMA PET is a more robust modality for biochemical recurrence with the potential of identifying small lesions which would otherwise be dismissed on MRI alone,” the authors wrote. “We recommend the use of 68Ga PSMA PET/MR for biochemical recurrent prostate cancer with potential to be the new standard of care for this indication.”

The results were presented by Juana Martinez, M.D., fellow in radiology at Weill Cornell Medical College in New York. 

PSMA PET combined with magnetic resonance imaging (MRI) is a promising technique in the evaluation of patients with prostate cancer. In this study, the researchers compared PSMA PET with concomitant multiparametric MRI in detecting lesions suspicious for biochemical prostate cancer recurrence. 

A review was performed of all patients with prostate cancer who prospectively enrolled in a clinical trial of 68Ga PSMA PET/MRI at New York Presbyterian Hospital - Weill Cornell campus from April 2018 to January 2021. Nuclear medicine physicians read the PSMA PET portion of the study and a radiologist with fellowship training in cancer imaging read the MRI of the skull base to thigh, independent of each other. Patient demographics, the indication for PSMA PET/MRI and serum prostate specific antigen (PSA) levels closest to the PSMA PET/MRI were extracted from patient charts.

Of the 165 patients who had a PSMA PET/MRI, 109 where imaged for biochemical recurrence. PSMA PET was able to detect more lesions suspicious for recurrence than MRI at all PSA levels. When assessing only patients who had PSMA PET/MRI for biochemical recurrent disease, PSMA PET fared superiorly at all PSA levels in comparison with MRI. 

“When compared with MRI, PSMA PET is highly robust in identifying lesions which are otherwise deemed unremarkable,” the authors wrote.

PSMA PET is highly robust in identifying prostate cancer lesions which are otherwise deemed unremarkable. 

Prostate-Specific Membrane Antigen PET Bests MRI in Biochemical Recurrent Disease 

The concurrent use of an artificial intelligence (AI) tool with digital breast tomosynthesis could improve the diagnostic performance of radiologists in the detection of breast cancer. This is according to a study presented at the 

 that also found that the addition of AI improved the efficiency of radiologists’ workflow.

“This AI system can be integrated into screening practice to improve both efficiency and accuracy of digital breast tomosynthesis,” the authors wrote.

The results were presented by Pierre Fillard, Ph.D., the founder and chief scientific officer of Therapixel SA in Nice, France.

The retrospective study aimed to determine the benefits that an AI tool could bring to the time and accuracy of digital breast tomosynthesis interpretation. A total of 22 breast specialist radiologists were asked to interpret 240 digital breast tomosynthesis examinations with and without the help of AI. The dataset included 114 biopsy-proven cancers, of which 36 were classified as false negative. Performances were measured in terms of area under the receiver operating characteristic curve (AUC), sensitivity, specificity and reading time.

The average AUC across readers was 0.79 without AI and 0.83 with AI, for an average improvement of 0.04 (95% CI: 0.02 to 0.06, 

 < .001). Average sensitivity improved from 80% without AI to 82% when using AI (2%; 95% CI: -0.4% to 0.4%), while specificity increased from 56% to 61% (5%; 95% CI: 1.5% to 8.7%). Average reading time was 74.7 seconds without AI and 70.9 seconds with AI (average difference: -3.8; 95% CI: -8.4 to 0.8). The reading time reduction varied in accordance with the likelihood of malignancy assigned by the AI, ranging from -15.6% for cases assigned with a low likelihood of malignancy to -0.5% for the most suspicious cases.

When applying these results to a screening population, the observed reading time was on average 76.2 seconds without the help of AI, which the authors noted “lies in the lower bound of the reading time reported for real-word practice.”

“Nonetheless, an average reduction of 8% was observed in assisted readers, which indicates that a regular batch reading (i.e., a sequential interpretation of screening mammograms without interruption) could include 13% more cases (about seven cases per hour) thus improving the efficiency of the screening program and reducing the time-to-diagnosis for patients,” the authors wrote.

An artificial intelligence for digital breast tomosynthesis enhances radiologists’ performance and efficiency. 

AI for Digital Breast Tomosynthesis Enhances Diagnostic Performance 

 suggest that magnetic resonance imaging (MRI) alone is a successful method for the follow-up in women who undergo breast-conserving treatment and ensures early detection of recurrent cancer.

“Women in the follow-up after breast cancer who have access to breast MRI may safely forgo additional mammographic or digital breast tomosynthesis follow-up,” the authors wrote.

The results were presented by Vanessa Raaff, Ph.D., of the department of diagnostic and interventional radiology, RWTH Aachen University Hospital in Germany.

For follow-up after breast conserving treatment, serial two-view mammography is recommended, possibly accompanied by targeted ultrasound. As breast MRI has been shown to be useful to improve breast cancer detection of recurrence in patients after breast conserving treatment, the researchers investigated the usefulness of MRI as a standalone imaging method for this purpose.

Between January 2011 and March 2021, a total of 426 women who had undergone MRI alone for routine follow-up after breast conserving surgery were included. The women started MRI screening at a median of two years after treatment and underwent MRI screening annually. Validation of the last negative MRI study was achieved by tomosynthesis plus clinical examination in 137 women and/or by clinical follow-up for at least two years in 289 women.

The women were followed by 1,553 MRI studies, covering a total 1,727 women years. Across the entire follow-up period, MRI was positive in 108/1,553 examinations (6.9%) and in 85/426 women (19.9%). Recurrent breast cancer was confirmed in 64/108 MRI studies and in 55/85 women, for a positive predictive value of 59.3% per positive MRI study and 64.7% per patient. 

The cancer-detection-rate was 37 per 1000 women years. Recurrent cancers were detected on average 8.9 years after breast conserving treatment. Of the 64 recurrent cancers, 17.2% were ductal carcinoma in situ and 82.8% were invasive. The mean size of invasive recurrent cancer was 11.4 mm, most frequently staged as T1b, followed by T1c.

“None of the women received a diagnosis of breast cancer in between MRI screening rounds, or within the two-year follow up after the respective last negative MRI, or upon digital breast tomosynthesis after the last study MRI,” the authors wrote.

Following breast cancer treatment, women who have access to breast MRI may safely forgo additional mammographic or digital breast tomosynthesis follow-up. 