Feature article

MR in specialty oncology

Oncology, the field of medicine that deals with cancer, has its roots in a number of different areas of the body. Because of this, a patient may be sent to an oncologist that has specialized in a specific type of oncology. Therefore, different types of cancers may require different types of oncologists. Magnetic resonance imaging (MRI) has been used to create clinical images which can be used for staging and monitoring cancer and its metastasis. Some physicians have also used it to monitor cancer therapies. New techniques and technologies are being researched and have begun emerging that may make MR scans even more important to the field of oncology and increase patient comfort and physician confidence.1,2

Breast Cancer

Women are typically imaged for breast cancer through the use of mammography, which has long been the norm. However, some patients may also need to have a breast MRI, especially if they have denser breast tissue than the average person.3 Dense breast tissue is harder for the mammogram to penetrate and may prevent the detection of breast cancers. Some women who are not at a high enough risk level to warrant a full MRI study may want to consider a "Fast MRI", in addition to mammography. This technique is primarily used for detecting invasive breast cancers. Fast MRI requires less scan and interpretation time and may be more cost effective.4 The standard breast MRI protocol for breast cancer imaging takes about 40 minutes, while the fast MRI takes about ten minutes.3,4 In a retrospective study, the fast MRI was roughly 93% accurate while the traditional breast MRI had a slightly higher rate.4 Doctors may view the scans after the radiologist has interpreted the image and decide whether a patient needs to come back or if a biopsy is needed.

Researchers in Austria have developed a possible new way to characterize and monitor a tumor.1 This method measures hypoxia and neovascularization in breast tumors. Hypoxia occurs when the cells within a tumor have lower oxygen concentrations compared to the surrounding healthy tissues, because of an imbalance between oxygen supply and consumption. It may increase the cancer's resistance to radiotherapy and some chemotherapy treatments. However, this technique, which is still being researched, may suffer from variation in oxygen levels in different regions and changes over time. This method may still be ultimately less expensive than PET scans and provide better spatial resolution compared to near-infrared spectroscopy. The measurement of hypoxia within the tumor may allow doctors to more accurately predict the progression and metastasis of cancer and the chances of patient survival.1

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Prostate Cancer

Men are tested for high levels of prostate specific antigen (PSA), and, if the test shows increased PSA levels, may need to have imaging or biopsy done to detect cancer. MRI is rapidly emerging as a great tool for a variety of clinical situations.2 This could be either before or after biopsy and may influence treatment decisions, diagnosis and surveillance. Diffusion weighted imaging (DWI) is an excellent tool for oncologists specializing in the prostate. DWI uses magnetic resonance to measure the influence of a strong magnetic field upon the random motion of molecules within the body.

A few different teams are researching the combination of MR technology and a new technology that may change biopsies and tumor removal surgeries through 3D printing.5,6 This method has been shown in cases of both prostate and brain cancer and may be useful in a wide variety of cancers. The patient may undergo an MRI which provides spatial information and images of the area being scanned. The images are then converted into a format that a 3D printer can understand, allowing for them to be printed and physically available for physicians and patients alike. Based on these images, the doctor may be able to more accurately plan for biopsy and tumor removal surgery. One of the advantages to this relates to the ability of the physician to adequately visualize the tumor and the structures that they need to avoid.5 The 3D model may also allow patients to understand their disease and how it is affecting their anatomy, as well as help them understand the surgical plan.5,6

Although oncology covers a wide variety of specialties, including breast and prostate cancer, the comfort of the patient and the confidence of the physician should certainly be considered once research has finished and clinical use has begun. Fast breast MRI could be used to image patients whose dense breast tissue may reduce the chance of their breast cancer being seen. Additionally, radiologists could see a reduction in scan and reconstruction time which would improve patient throughput. Using new techniques that measure hypoxia and diffusion may increase a doctor's confidence in diagnosing a patient and monitoring the progression of cancer. Likewise, 3D printing could increase patient comfort through familiarization with the process in patients.

References

1. Cynthia E. Keen. "MRI measures breast cancer hypoxia." physicsworld.com. 24 January 2019. Web. 25 January 2019. <https://physicsworld.com/a/mri-measures-breast-cancer-hypoxia/>.

2. Isabelle Boulay Coletta. "Synthetic diffusion: a robust sequence for prostate cancer diagnosis and patient management." Signa Pulse. Autumn 2017. Web. 24 January 2019. <https://beta.gehealthcare.com//-/media/8795fd25085c4a708cd3a0be81b6f0b3.pdf>.

3. "What is a 'Fast Breast MRI Study'?" PennMedicine.org. Web. 25 January 2019. <https://www.pennmedicine.org/for-patients-and-visitors/find-a-program-or-service/radiology/breast-imaging/breast-imaging-services/fast-breast-mri>.

4. Staff News Brief. "FAST breast MRI can replace conventional breast MRI." AppliedRadiology.com. 17 January 2017. Web. 25 January 2019. <https://appliedradiology.com/articles/fast-breast-mri-can-replace-conventional-breast-mri>.

5. Nick Klenske. "3D Printed Prostate Cancer Models Aid Pre-Surgical Planning, Patient Care." RSNA Daily Bulletin. 27 November 2018. Web. 24 January 2019. <https://rsna2018.rsna.org/dailybulletin/index.cfm?pg=18tue03>.

6. Anicka Slachta. "Novel 3D-printing technique generates full anatomical models from MRI, CT scans." RadiologyBusiness.com. 30 May 2018. Web. 25 January 2019. <https://www.radiologybusiness.com/topics/care-delivery/novel-3d-printing-technique-generates-full-anatomical-models-mri-ct-scans>.