MRI is an established modality for evaluating head and neck malignancies because it can differentially identify fat, fluid, blood, bone marrow, muscle and soft tissue on a scale of gray and delineates the true local extent better than any other modality: diseased area shines distinctly and differently from normal.
MRI is a preferred technique for evaluation of cartilage involvement in laryngeal cancer, so is in detailing infiltration of deep spaces of neck and to identify perineural intracranial extension commonly encountered in nasopharyngeal carcinomas or lesions close to skull base at presentation.
Accurate image registration of PET and MRI, as compared to sequentially acquired PET and CT images, gives the much-desired edge to match FDG uptake on MR based suspicious areas to reduce chances of uncertainty in tissue classification. Thus PET/ MRI has been seen to play a pivotal role in assessing early post-Op residual and post Op/RT recurrent disease where the planes are distorted and effaced, not comparable to other modalities.
Like nasopharyngeal carcinomas that may be metastatic at presentation ( about 8-10 % of cases with common sites being nodes, bones lung, liver, and retroperitoneal nodes) for other metastatic head and neck cancers, Simultaneous PET/MRI has been found very useful technique in evaluating the local disease and distant metastasis equally well in a single examination.MRI supersedes CT in delineating marrow lesions much better(with or without cortical involvement).
Note: CT on the other hand, is less sensitive for detecting marrow lesions in the bone till the cortex is involved.
Uncooperative patients and patients with involuntary motion need to be briefly sedated for better results. We found PET/MRI results more decisive and aids in addressing clinical questions better.
53 year old male, a diagnosed case of Ca left lateral border of the tongue(2009) Underwent WLE. Recurrence in left lower alveolus 2012. Left alveolar commando with PMMC with tracheostomy Feb 2012. HPE: SCC with positive mucosal margins. Post RT. Developed recurrent left tonsillar lesion. Post RT till June 2013. PET MRI done was done for evaluation.
Axial CT (A) and PET CT fused (B) images reveal metabolic activity in the left tonsillar fossa. The lesion is appreciated on fused PET CT image and barely discernible on CT.
Axial MR- T2 ©, PET / MR fused (D) images bring a better delineation of the lesion on MR.
This short PET-MRI Scan case was compiled by Dr. Sangeeta Taneja and Dr. Amarnath Jena (Nuclear Medicine Physician at PET-Suite @ Indraprastha Apollo Hospital, Sarita Vihar).
Read More about PET-MRI Scan at House Of Diagnostics in Delhi and NCR.
The Simultaneous PET-MRI Scan is currently offered at PET-Suite at Apollo Hospital, Sarita Vihar.