Workflow in Simultaneous PET/MRI

Barbosa, Felipe de Galiza; Schulthess, G; Veit-Haibach, Patrick

doi:10.1053/j.semnuclmed.2015.03.007

Cited by 34 publications

(16 citation statements)

References 78 publications

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“…Third, the absence of preparation pulses or multiple echoes makes ZTE a time-efficient acquisition (i.e., most of the repetition time is used to acquire data) and suitable for routine clinical use. Indeed, on PET/MR, the total MR acquisition time is generally longer than that of PET, and any options to minimize or accelerate MR acquisition time should be considered (30). Fourth, the current ZTE-AC has the capability of assigning continuous attenuation values to bone tissue, rather than discrete ones.…”

Section: Discussionmentioning

confidence: 99%

Clinical Evaluation of Zero-Echo-Time Attenuation Correction for Brain ¹⁸F-FDG PET/MRI: Comparison with Atlas Attenuation Correction

et al. 2016

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Accurate attenuation correction (AC) on PET/MR is still challenging. The purpose of this study was to evaluate the clinical feasibility of AC based on fast zero-echo-time (ZTE) MRI by comparing it with the default atlas-based AC on a clinical PET/MR scanner. Methods: We recruited 10 patients with malignant diseases not located on the brain. In all patients, a clinically indicated whole-body 18 F-FDG PET/CT scan was acquired. In addition, a head PET/MR scan was obtained voluntarily. For each patient, 2 AC maps were generated from the MR images. One was atlas-AC, derived from T1-weighted liver acquisition with volume acceleration flex images (clinical standard). The other was ZTE-AC, derived from proton-density-weighted ZTE images by applying tissue segmentation and assigning continuous attenuation values to the bone. The AC map generated by PET/CT was used as a silver standard. On the basis of each AC map, PET images were reconstructed from identical raw data on the PET/MR scanner. All PET images were normalized to the SPM5 PET template. After that, these images were qualified visually and quantified in 67 volumes of interest (VOIs; automated anatomic labeling, atlas). Relative differences and absolute relative differences between PET images based on each AC were calculated. 18 F-FDG uptake in all 670 VOIs and generalized merged VOIs were compared using a paired t test. Results: Qualitative analysis shows that ZTE-AC was robust to patient variability. Nevertheless, misclassification of air and bone in mastoid and nasal areas led to the overestimation of PET in the temporal lobe and cerebellum (%diff of ZTE-AC, 2.46% ± 1.19% and 3.31% ± 1.70%, respectively). The j%diffj of all 670 VOIs on ZTE was improved by approximately 25% compared with atlas-AC (ZTE-AC vs. atlas-AC, 1.77% ± 1.41% vs. 2.44% ± 1.63%, P , 0.01). In 2 of 7 generalized VOIs, j%diffj on ZTE-AC was significantly smaller than atlas-AC (ZTE-AC vs. atlas-AC: insula and cingulate, 1.06% ± 0.67% vs. 2.22% ± 1.10%, P , 0.01; central structure, 1.03% ± 0.99% vs. 2.54% ± 1.20%, P , 0.05). Conclusion: The ZTE-AC could provide more accurate AC than clinical atlas-AC by improving the estimation of head-skull attenuation. The misclassification in mastoid and nasal areas must be addressed to prevent the overestimation of PET in regions near the skull base.

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Section: Discussionmentioning

confidence: 99%

Clinical Evaluation of Zero-Echo-Time Attenuation Correction for Brain ¹⁸F-FDG PET/MRI: Comparison with Atlas Attenuation Correction

et al. 2016

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“…Entegre PET/MR incelemeleri manyetik ortamda çalışabilen yeni PET foton çoğaltıcı tüp teknolojilerinin geliştirilmesi ve bu iki görüntülemeyi eş zamanlı yapabilen iç içe geçmiş sistemlerin üretilmesi ile klinik kullanıma girmiştir (1,2,3). PET verisi için atenüasyon düzeltmesi işleminin MR görüntüleri kullanılarak gerçekleştirilmesi hastanın maruz kaldığı radyasyon dozunu azaltırken, diğer taraftan lezyonların MR görüntülemenin üstün yumuşak doku kontrastı ile belirlenmesine olanak sağlamaktadır.…”

Section: Entegrepet/mrgörüntülemeyöntemiunclassified

“…Bunun için PET görüntülemenin sağladığı tanısal bilgiyi tekrarlayan, bu bakımdan incelemeye ek katkısı olmayan MR sekanslarının PET/MR tetkiki sırasında alınmaması uygun olacaktır (2). Tüm vücut FDG PET görüntülemenin birçok onkolojik endikasyonda yüksek duyarlılığa ve özgüllüğe sahip olmasına bağlı olarak ek tanısal MR görüntüleme yapılması gerekmeyebilir (14).…”

Section: Bölgeselpet/mrçalışmalarıveözeldurumlarunclassified

“…Baş-boyun bölgesinde aktif lenfoid dokularda, kaslarda ve tükürük bezlerinde gözlenen fizyolojik artmış FDG tutulumlarının patolojik FDG tutulumlarından ayrımında da MR görüntülerinin sağladığı yüksek yumuşak doku kontrastından yararlanılır. Ancak tedavi sonrasında yanıt belirlemede ve izlemde, FDG PET görüntülemenin yüksek negatif öngörü değerine sahip olduğu da dikkate alındığında, tek bir planda yüksek rezolüsyonlu bir T2 görüntüsü almak yeterli olabilir (2,19).…”

Section: Baş-boyunkanserleriunclassified

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Daily Workflow and Protocol Optimization in Positron Emission Tomography/Magnetic Resonance Imaging Use

Akdemir¹,

Karabacak²

2017

Nts

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Entegre pozitron emisyon tomografi/manyetik rezonans (PET/MR) sistemlerinde, klinik görüntüleme protokollerinin yöntemin maliyet bakımından etkin bir biçimde kullanılacak biçimde tasarlanması ve hastanın toleransının gözetilmesi için en önemli değişken toplam görüntüleme süresidir. Onkolojik tüm vücut florodeoksiglukoz (FDG) PET/MR incelemesinin tüm vücut PET/bilgisayarlı tomografi (BT) ile benzer biçimde 30 dakikanın altındaki bir sürede tamamlanması üzerinde görüş birliğine varılan bir konudur. Aynı zamanda PET/MR incelemesi sırasında alınan MR görüntülerinin tanıya katkısının en az düşük doz BT görüntülemesi ile benzer düzeyde olması gerekir. Entegre PET/MR çalışmalarında PET görüntüleme tanısal bilginin esas unsuru olduğundan, tanısal MR çalışmalarından farklı olarak entegre PET/MR sistemleri için özel olarak planlanmış sınırlı bir sürede tamamlanabilecek ve PET bulgularına katkı yapabilecek MR protokolleri uygulanmalıdır. Onkolojik tüm vücut FDG PET/MR çalışmalarında en yaygın olarak başvurulan yaklaşım, aksiyal ve/veya koronal T1 ve T2 ağırlıklı MR görüntülerinin PET görüntüleme süresi içinde ve PET verisi ile eş zamanlı olarak kaydedilmesidir. Gerektiğinde incelenen hastalığa ve klinik endikasyona göre belirli bir bölgenin toplam görüntüleme süresini uzatmayacak şekilde ek MR sekansları ile görüntülenmesi de olanaklıdır. Klinik çalışmalar bu yaklaşımın onkolojide PET/BT ile aynı derecede başarılı sonuçlar verdiğini göstermektedir. Bu yazıda literatür verilerinden ve kendi deneyimimizden yola çıkarak entegre PET/MR sisteminin klinikte nasıl kullanıldığı işlenmekte ve nasıl kullanılması gerektiği konusu tartışılmaktadır. Anahtar Kelimeler: Tanısal görüntüleme, pozitron emisyon tomografi, manyetik rezonans görüntüleme In order to use integrated positron emission tomography/ magnetic resonance (PET/MR) systems in a cost-effective way and to make the examination tolerable for patients, total imaging time is the most important parameter of clinical imaging protocols. The general consensus states that an oncological whole-body fluorodeoxyglucose (FDG) PET/MR examination should be completed within 30 minutes, similarly to the whole-body PET/computerized tomography (CT) examination. At the same time, the MR images acquired during the whole-body PET/MR examination should contribute to diagnosis as well as the low-dose CT images acquired in the PET/CT examination. Since the PET part comprises the main diagnostic information in integrated PET/MR studies, specifically established MR protocols are necessary that differ from diagnostic MR studies and which may be completed in a limited time and make a contribution to evaluation of PET findings. The most commonly used protocol in oncological whole-body FDG PET/MR studies is to have axial and/or coronal T1-and T2-weighted MR images simultaneously within the PET acquisition time window. This protocol may also involve acquisition of additional MR sequences which may be necessary according to the clinical diagnostic indication and that will not extend the total imagi...

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“…The total PET-MRI scan time is often limited by MRI acquisition times and will depend on which areas need to be imaged. Whole-body protocols, e.g., to study musculoskeletal pain, have been proposed that acquire 5-6 "bed" positions, each 3-5 minutes that include a combination of anatomical and functional MRI scans (42,43). Designated protocols where the anatomy of interest is contained in one PET bed, e.g., for the knee, permit longer MRI protocols and the duration of scan time to be used to acquire PET data.…”

mentioning

confidence: 99%

Potential of PET-MRI for imaging of non-oncologic musculoskeletal disease

Kogan

Fan

Gold

2016

Quant. Imaging Med. Surg.

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Early detection of musculoskeletal disease leads to improved therapies and patient outcomes, and would benefit greatly from imaging at the cellular and molecular level. As it becomes clear that assessment of multiple tissues and functional processes are often necessary to study the complex pathogenesis of musculoskeletal disorders, the role of multi-modality molecular imaging becomes increasingly important.New positron emission tomography-magnetic resonance imaging (PET-MRI) systems offer to combine high-resolution MRI with simultaneous molecular information from PET to study the multifaceted processes involved in numerous musculoskeletal disorders. In this article, we aim to outline the potential clinical utility of hybrid PET-MRI to these non-oncologic musculoskeletal diseases. We summarize current applications of PET molecular imaging in osteoarthritis (OA), rheumatoid arthritis (RA), metabolic bone diseases and neuropathic peripheral pain. Advanced MRI approaches that reveal biochemical and functional information offer complementary assessment in soft tissues. Additionally, we discuss technical considerations for hybrid PET-MR imaging including MR attenuation correction, workflow, radiation dose, and quantification.

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Workflow in Simultaneous PET/MRI

Cited by 34 publications

References 78 publications

Clinical Evaluation of Zero-Echo-Time Attenuation Correction for Brain ¹⁸F-FDG PET/MRI: Comparison with Atlas Attenuation Correction

Clinical Evaluation of Zero-Echo-Time Attenuation Correction for Brain ¹⁸F-FDG PET/MRI: Comparison with Atlas Attenuation Correction

Daily Workflow and Protocol Optimization in Positron Emission Tomography/Magnetic Resonance Imaging Use

Potential of PET-MRI for imaging of non-oncologic musculoskeletal disease

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Workflow in Simultaneous PET/MRI

Cited by 34 publications

References 78 publications

Clinical Evaluation of Zero-Echo-Time Attenuation Correction for Brain 18F-FDG PET/MRI: Comparison with Atlas Attenuation Correction

Clinical Evaluation of Zero-Echo-Time Attenuation Correction for Brain 18F-FDG PET/MRI: Comparison with Atlas Attenuation Correction

Daily Workflow and Protocol Optimization in Positron Emission Tomography/Magnetic Resonance Imaging Use

Potential of PET-MRI for imaging of non-oncologic musculoskeletal disease

Contact Info

Product

Resources

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Clinical Evaluation of Zero-Echo-Time Attenuation Correction for Brain ¹⁸F-FDG PET/MRI: Comparison with Atlas Attenuation Correction

Clinical Evaluation of Zero-Echo-Time Attenuation Correction for Brain ¹⁸F-FDG PET/MRI: Comparison with Atlas Attenuation Correction