The value of magnetic resonance imaging in target volume delineation of base of tongue tumours – A study using flexible surface coils

Ahmed, Merina; Schmidt, María Auxiliadora; Sohaib, Aslam; Kong, Christine; Burke, K.; Richardson, Cheryl; Usher, Marianne; Brennan, Sinead; Riddell, Angela M.; Davies, Mark; Newbold, Kate; Harrington, Kevin; Nutting, Christopher M.

doi:10.1016/j.radonc.2009.12.021

Cited by 63 publications

(61 citation statements)

References 21 publications

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“…MRI has a number of advantages over CT in the head and neck region, including robustness to dental artefacts and improved soft-tissue contrast, either with or without the use of contrast agents [1,2]. The improved visualisation and delineation of organs at risk and tumours has been shown to be of value in the planning of nasopharyngeal [3], sinonasal [4] and oropharyngeal [5] cancers. For tumour sites lower down, the case is less conclusive and is further complicated by the difficulty in fusing MRI with CT in this region [6].…”

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confidence: 99%

Commissioning of a new wide-bore MRI scanner for radiotherapy planning of head and neck cancer

Liney

Owen²,

Beaumont³

et al. 2013

BJR

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Objective: A combination of CT and MRI is recommended for radiotherapy planning of head and neck cancers, and optimal spatial co-registration is achieved by imaging in the treatment position using the necessary immobilisation devices on both occasions, something which requires wide-bore scanners. Quality assurance experiments were carried out to commission a newly installed 1.5-T widebore MRI scanner and a dedicated, flexible six-channel phased array head and neck coil. Methods: Signal-to-noise ratio (SNR) and spatial signal uniformity were quantified using a homogeneous aqueous phantom, and geometric distortion was quantified using a phantom with water-filled fiducials in a grid pattern. Volunteer scans were also used to determine the in vivo image quality. Clinically relevant T 1 weighted and T 2 weighted fat-suppressed sequences were assessed in multiple scan planes (both sequences fast spin echo based). The performance of two online signal uniformity correction schemes, one utilising low-resolution reference scans and the other not utilising low-resolution reference scans, was compared. Results: Geometric distortions, for a 635-kHz bandwidth, were ,1 mm for locations within 10 cm of the isocentre rising to 1.8 mm at 18 cm away. SNR was above 50, and uniformity in the axial plane was 71% and 95% before and after uniformity correction, respectively. Conclusion: The combined performance of the wide-bore scanner and the dedicated coil was adjudged adequate, although superior-inferior spatial coverage was slightly limited in the lower neck. Advances in knowledge: These results will be of interest to the increasing number of oncology centres that are seeking to incorporate MRI into planning practice using dedicated equipment.

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mentioning

confidence: 99%

Commissioning of a new wide-bore MRI scanner for radiotherapy planning of head and neck cancer

Liney

Owen²,

Beaumont³

et al. 2013

BJR

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“…MRI has reduced interference from metal implants such as prosthetic hips [2] and gold seed implants and therefore has the potential to provide improved target volume delineation over CT. Changes in anatomical and tumour definition as a result of using MRI data compared with CT have been reported for prostate [2][3][4][5][6][7], head and neck [8][9][10][11] and brain cancer [12,13] patients.…”

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confidence: 99%

The influence of MRI scan position on image registration accuracy, target delineation and calculated dose in prostatic radiotherapy

Hanvey¹,

Sadozye²,

McJury³

et al. 2012

BJR

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Objective: To investigate the necessity of performing MRI in the radiotherapy position when using MRI for prostatic radiotherapy. Methods: 20 prostate patients received a CT, diagnostic MRI and an MRI scan in the radiotherapy position. The quality of registration between CT and MRI was compared between the two MRI set-ups. The prostate and seminal vesicles were contoured using all scans and intensity modulated radiotherapy (IMRT) plans were generated. Changes in the target volume and IMRT plans were investigated. Two-tailed paired Student's ttests determined the statistical significance.Results: There was a decrease in the mean distance from the centre of the bony anatomy between CT and MRI (from 3.9 to 1.9 mm, p-value,0.0001) when the MRI scan was acquired in the radiotherapy position. Assuming that registering CT with an MRI scan in the radiotherapy position is the gold standard for delineating the prostate and seminal vesicles, using a planning target volume delineated on the CT with a diagnostic MRI scan viewed separately, resulted in a mean conformation number of 0.80 instead of the expected 0.98 (p,0.0001). Conclusion: By registering CT with an MRI scan in the radiotherapy position, there is a statistically significant improvement in the registration and IMRT quality. Advances in knowledge: To achieve an acceptable registration and IMRT quality in prostatic radiotherapy, neither CT with a separate diagnostic MRI nor CT registered to a diagnostic MRI will suffice. Instead, a CT registered with an MRI in the radiotherapy position should be used.

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“…Importantly, no detrimental effect on locoregional control was observed with volumetric contouring. [7][8][9] Several planning studies have underlined the benefit of incorporating MR images in head and neck radiotherapy planning with improvement of tumour delineation and reduction in interobserver variations compared with CT. [10][11][12] It also enables a more accurate delineation of neurological OARs such as the spinal cord, brain stem, optic chiasm and hippocampus, which is vital to avoid irreversible neurological sequelae. Nevertheless, the accuracy of MRI in this context is hugely dependent on the scanning position.…”

Section: Anatomical Mri Sequencesmentioning

confidence: 99%

The emerging potential of magnetic resonance imaging in personalizing radiotherapy for head and neck cancer: an oncologist's perspective

Wong

Panek

Bhide

et al. 2017

The British Journal of Radiology

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Head and neck cancer (HNC) is a challenging tumour site for radiotherapy delivery owing to its complex anatomy and proximity to organs at risk (OARs) such as the spinal cord and optic apparatus. Despite significant advances in radiotherapy planning techniques, radiation-induced morbidities remain substantial. Further improvement would require high-quality imaging and tailored radiotherapy based on intratreatment response. For these reasons, the use of MRI in radiotherapy planning for HNC is rapidly gaining popularity. MRI provides superior soft-tissue contrast in comparison with CT, allowing better definition of the tumour and OARs. The lack of additional radiation exposure is another attractive feature for intratreatment monitoring. In addition, advanced MRI techniques such as diffusion-weighted, dynamic contrast-enhanced and intrinsic susceptibility-weighted MRI techniques are capable of characterizing tumour biology further by providing quantitative functional parameters such as tissue cellularity, vascular permeability/perfusion and hypoxia. These functional parameters are known to have radiobiological relevance, which potentially could guide treatment adaptation based on their changes prior to or during radiotherapy. In this article, we first present an overview of the applications of anatomical MRI sequences in head and neck radiotherapy, followed by the potentials and limitations of functional MRI sequences in personalizing therapy. INTRODUCTIONRadical radiotherapy (RT) is integral to the management of head and neck cancer (HNC) in both the primary and adjuvant settings. Advances in computer-assisted radiological techniques over the past two decades have in turn revolutionized radiotherapy planning. Development of advanced radiotherapy planning techniques such as intensity-modulated radiotherapy (IMRT) and volumetricmodulated arc therapy have allowed for better dose conformation to the tumour target and sparing of surrounding normal tissues. HNC was one of the first tumour sites where IMRT was widely implemented owing to a significant reduction in radiation-induced xerostomia in comparison with three-dimensional conformal planning.

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The value of magnetic resonance imaging in target volume delineation of base of tongue tumours – A study using flexible surface coils

Cited by 63 publications

References 21 publications

Commissioning of a new wide-bore MRI scanner for radiotherapy planning of head and neck cancer

Commissioning of a new wide-bore MRI scanner for radiotherapy planning of head and neck cancer

The influence of MRI scan position on image registration accuracy, target delineation and calculated dose in prostatic radiotherapy

The emerging potential of magnetic resonance imaging in personalizing radiotherapy for head and neck cancer: an oncologist's perspective

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