Imaging modalities in pregnant cancer patients

Abstract

Cancer during pregnancy is increasingly diagnosed due to the trend of delaying pregnancy to a later age and probably also because of increased use of non-invasive prenatal testing for fetal aneuploidy screening with incidental finding of maternal cancer. Pregnant women pose higher challenges in imaging, diagnosis, and staging of cancer. Physiological tissue changes related to pregnancy makes image interpretation more difficult. Moreover, uncertainty about the safety of imaging modalities, fear of (unnecessary) fetal radiation, and lack of standardized imaging protocols may result in underutilization of the necessary imaging tests resulting in suboptimal staging. Due to the absence of radiation exposure, ultrasound and MRI are obvious first-line imaging modalities for detailed locoregional disease assessment. MRI has the added advantage of a more reproducible comprehensive organ or body region assessment, the ability of distant staging through whole-body evaluation, and the combination of anatomical and functional information by diffusion-weighted imaging which obviates the need for a gadolinium-based contrast-agent. Imaging modalities with inherent radiation exposure such as CT and nuclear imaging should only be performed when the maternal benefit outweighs fetal risk. The cumulative radiation exposure should not exceed the fetal radiation threshold of 100 mGy. Imaging should only be performed when necessary for diagnosis and likely to guide or change management. Radiologists play an important role in the multidisciplinary team in order to select the most optimal imaging strategies that balance maternal benefit with fetal risk and that are most likely to guide treatment decisions. Our aim is to provide an overview of possibilities and concerns in current clinical applications and developments in the imaging of patients with cancer during pregnancy.

Keywords: interventional; neoplasm metastasis; neoplasms; radiology.

Figure 1

Diffusion-weighted imaging-based characterization of (A, C, E) benign biliary cyst (arrow) versus (B, D, F) malignant liver metastases (dashed arrow). (A) the signal decay curve of the biliary cyst shows strong decrease in signal intensity over the consecutive b-value sequences resulting in high calculated apparent diffusion coefficient. (C) on the b1000 image. The biliary cyst appears with low signal intensity and (E) white on the apparent diffusion coefficient map. (B) the signal decay curve of the liver metastasis shows only a limited decrease in signal intensity over the consecutive b-value sequences, resulting in a low calculated apparent diffusion coefficient. (D) on the b1000 image, the liver metastasis appears bright and (F) dark on the apparent diffusion coefficient map.

Figure 2

Pregnant patient with locally advanced breast cancer: breast ultrasound shows (A) large tumorous mass in the left breast with (B) a regional lymphadenopathy in the left axilla. (C) screening ultrasound is equivocal. at whole body diffusion-weighted MRI, (D) the b1000 diffusion-weighted sequence shows a bright lesion in the liver, corresponding to a solid lesion at (E) T2-weighted sequence compatible with liver metastasis (arrows). Additionally, (F) the b1000 diffusion-weighted sequence confirms the lymph node metastasis (arrowheads) as a bright lesion and nodular shape at (G) T1-weighted sequence and shows a bright lesion corresponding to T1 hypo-intensity in the left femur compatible with bone metastasis (dashed arrows).

Figure 3

Incidental finding of Hodgkin lymphoma after suspect non-invasive prenatal testing in pregnant patient: at whole-body diffusion-weighted MRI, (A) the b1000 diffusion-weighted sequence shows bright and enlarged lymphadenopathies in the bilateral base of neck (arrows) and two bright lesions of bone marrow involvement located at the right acetabulum and the fourth lumbar vertebral body corresponding to diffuse hypo-intensity at (B) the T1-weighted sequence. (C) interim whole-body diffusion-weighted MRI after two cycles of chemotherapy shows complete response. (D) complete response is confirmed at end of treatment hybrid positron emission tomography/CT after delivery.

Figure 4

Pregnant patient with diagnosis of uterine cervical cancer. (A–C) T2-weighted MRI combined with (D, E) diffusion-weighted imaging of the pelvis shows a large tumorous mass (asterisk) in the cervix and prolabating in the proximal vagina without parametrial invasion but with bilateral para-iliac lymphadenopathies (arrows). (F) staging chest CT shows an osteolytic lesion in the right scapula compatible with skeletal metastasis.

Figure 5

Pregnant patient diagnosed with a malignant ovarian mass at gynecological ultrasound. (A, C) B1000 whole-body diffusion-weighted MRI shows multifocal and diffuse bright confluent peritoneal and pleural lesions compatible with diffuse metastases. correlative. (B, D) T2-weighted images show thickening of the peritoneal planes, ascites respectively bilateral pleural fluid.