Prompted by the lively recent debate about the possible carcinogenic risk in cardiac imaging for detecting coronary artery disease, Swiss researchers say they've found no significant differences between ultralow-dose coronary CT angiography (CCTA) and cardiovascular MR (CMR) imaging in this area.
Reports about the immediate post-CMR DNA double-strand breaks in T lymphocytes have prompted concern, but detailed evidence of CMR-induced DNA damage in lymphocytes, alterations of blood cells, and their temporal persistence have not emerged. Against this background, Dr. Julia Stehli and colleagues from the cardiac imaging section in the department of nuclear medicine at Zurich University Hospital decided to compare the carcinogenic potential of ultralow-dose CCTA with that of routine CMR.
Statements about the clinical relevance of DNA double-strand breaks are impossible, Dr. Julia Stehli told ESC 2016 delegates.As a surrogate marker for carcinogenic risk, the group assessed DNA double-strand breaks (DSBs) before and after noninvasive imaging with flow cytometry in the peripheral blood mononuclear cells of patients who were consecutively recruited to undergo either CMR (n = 20) or ultralow-dose CCTA (n = 21).
All CCTAs were performed on a 64-slice CT unit. To achieve an ultralow-dose exam, tube voltage and current were adapted to body mass index (BMI [kg/m2] / tube voltage [mA] / tube current [kV]: < 22.5/150/80, 22.5-24.9/165/80, 25.0-27.4/180/80; 27.5-29.9/195/80, ± 30.0/210/100). The images were reconstructed using a novel, model-based iterative reconstruction algorithm, Stehli explained.
The team performed CMR according to the standard clinical protocol (gradient echo, steady-state and balanced free precession, FastSE, T2-weighted double-inversion black-blood spin-echo, inversion-recovery segmented gradient echo) on a 1.5-tesla MR system.
There was no significant differences between the two groups in terms of age, gender, or BMI (p > 0.05), she reported. The average effective radiation dose in the CCTA group was 0.26 ± 0.11 mSv. Analysis of flow cytometry revealed that both ultralow-dose CCTA and CMR induced a significant increase in DSBs (p < 0.01) without significant difference between CCTA and CMR (p = 0.497), as shown in the figure.
Technical refinements that allow CCTA with a submillisievert fraction of effective radiation dose for the accurate interpretation of coronary arteries lead to very low induction of DSBs, comparable to that of after routine CMR, according to Stehli.
"We cannot say anything about the clinical relevance of DNA double-strand breaks," she told attendees during a moderated poster session at last week's European Society of Cardiology (ESC) congress in Rome. The more radiation dose we use, the more DNA double-strand breaks we get, but we cannot say whether this leads to cancer, she added.
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnieeurope.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&fit=crop&h=100&q=70&w=100)
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnieeurope.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)
