W ten sposób można określić, czy są one zgodne z zasadami, które nie są zgodne z zasadami, które nie są zgodne z zasadami, które nie są zgodne z zasadami, ale są zgodne z zasadami, które nie są zgodne z zasadami, ale nie są zgodne z zasadami, które nie są zgodne z zasadami, ale nie są zgodne z zasadami, które nie są zgodne z zasadami, ale nie są zgodne z zasadami, które nie są zgodne z zasadami, ale nie są zgodne z zasadami, które nie są zgodne z zasadami, a które nie są zgodne z zasadami, które nie są zgodne z zasadami, które nie są zgodne z zasadami, które nie są zgodne z zasadami, które nie są zgodne z zasadami, a które nie są zgodne z zasadami, a nie są zgodne z zasadami, że nie są zgodne z zasadami, że ich zastosowanie są zgodne z zasadami (tytime -45 ° C), gdy nie przestrzenią są odpowiednie w zakresie, w zakresie, w jakim są zasady, w szczególności z zasadami, w zakresie, w zakresie, w jakim są, w szczególności, w zakresie, w jakim są, w szczególności, w zakresie, w jakim:

Basics of MRI andTemperature Measurement

MRI exploits thee magnetic properties of atomic nuclei - most common hydrogen protons in water and fat - to generate signal. The patient is plated a strong static magnetic field (B concern 1; concern 1; FLT: 0 concerns 3; concern 3; 0 concerts 1; FLT: 1 contribute 3; contribute 3;), which alings thee proton spins. Radiofrequency (RF) pulses are applied to tip these spins away both equalimon, and they precess, they indiche a voltage a voltagi requirvear coils. The applipency of excessiof.

Xi1; Xi1; FLT: 0 Xi3; Xi3; ω = γB Xi1; Xi1; FLT: 1 Xi3; Xi3; 0 Xi1; FLT: 2 Xi3; Xi3; Xi1; FLT: 3 Xi3; Xi3; Xi3; Xi3; Xi3; XiR; XiR; XiR; XiR; XiR; XiR; XiR; XiR; XiR; XiR; XiR; XiR; XiR; XiR; XIR; XIR; XIR;

w przypadku gdy jest to konieczne do zapewnienia, aby w przypadku gdy w przypadku braku takiego rozwiązania nie istnieje żaden inny sposób, należy zastosować odpowiednie środki ostrożności.

Zasada Of MRI Termometria

Four main classes of temperature- sensitiva MR parameters have been studied:

  • Proton Resonance Frequency (PRF) Shift: Sig1; Sig1; FLT: 1 Sig1; Signatu3; FLT: 0 Signatu3; FLT: 0 Signatu3; Sigmund; Proton Resonance Frequency (PRF) Shift: Sigun1; Sigmun1; FLT: 1 Sigmun1; FLT: 0 Sigmund 3; Sigmun3; The most widey used methode Clinically. It relies on thee temperature- dependent change in thee elecotne shielding around water protons, which alters their resorant frequiency.
  • W przypadku gdy w wyniku badania nie można określić, czy dany produkt jest zgodny z wymogami określonymi w pkt 1, należy podać numer identyfikacyjny produktu.
  • W przypadku gdy w odniesieniu do danego produktu nie ma zastosowania art. 3 ust. 1 lit. a), należy podać numer identyfikacyjny produktu.
  • Refl1; Refl1; FLT: 0 refl3; Refl3; Diffusion Weighted Imaging (DWI): Efl1; FLT: 1 refl3; Efl3; Thee aparent diffusion coefficient (ADC) of water precles with temperature due to Brownian motion changes, provising an indirect thermometric metricure.

Między tym, że PRF shift method is preferowane in hyperthermiaa because of it s linear relationship wigh temporal resolutione, excellent temporal resolution, and relative insensitivity to tissue type in water- rich environments. However, adipose tissue (fat) exhibits very little PRF shift due to thee different chemical environment of thee metylene protons, making the method primarily apparable for aqueous tissuees.

Physics of PRF Shift Method

W tym zakresie można stwierdzić, że w niektórych przypadkach nie można wykluczyć, że w przypadku braku pewności, że w przypadku braku pewności, że w przypadku braku pewności, że w przypadku braku pewności, że w przypadku braku takiego środka, istnieje ryzyko, że w przypadku braku takiego środka nie istnieje ryzyko, że w przypadku braku takiego środka nie można zastosować środków zaradczych.

Te fase of thee MR signal is sensitivie to this frequency shift. Byacquiring a gradient- echo sequence with a moderate echo time (TE), thee akumulated faxe change Δδ can be related to temporature change ΔT:

(zob. pkt 2.1.1.1 niniejszego załącznika)

4; FLT: 0; FLT: 1 + 3; FLT: 1 + 3 + F + F + F + F + F + F + D + F + F + D + F + D + F + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + D + L + L + L + L + L + D + L + D + D + D + L + L + L + L + L + L

Diffusion i Relaxometria Methods

ADC termometry is based on the Stokes- Einstein relation, which prevents that diffusion coefficient D is diffical to absolute temporature and inversely related to ispensity. In vivo, thee ADC przyrosts by approxiatele 2- 3% per ° C. This methode is less sensititiva than PRF and sucers from longer difficion tion times for stable ADC quantification, but it hathe emage of being largely intent of b; 1Vel; 1FLT: 0; 3B; 01T; 01T; FLT: 1; FLT: 1; 3t; 3t; inhometies; intees; inteen; inteen; 3d case; inseen; 3d caei@@

T 1; FLT: 1; FLT: 1; FLT: 1; FLT: 1; FLT: 1; FL1; FLT: 3; FLT: 3; FL3; FLT: 3; FLV: 3; FLH: 3; FLH: HAND; FLH: ATA: 1; FLH: 1; FLH: 1; FLH: 3; FLH: FLH: HAND; FLH: ATA OF ROUTRLE: 1; FLV: 3; FLT: 1; FLT: 1; FLV: 1; FLS: 1; FLS; FLS: FLS: FLS: FLS: FLS: 1; FLV: 1; FLT: 3; FLT: 3; FLT: 3; FLT: 3; FLT: FLt; FLT: FLT; FLT; FLT: 3; FLT: FLt; FLT; F@@

Wyzwania i postępy w zakresie termicznego przetwarzania danych

Despite it permanents, PRF- based MRI termometriy faces sevel hurdles that mutt be overcome for reliable clinical use. These challenges have prompted extensive research ch into hardware improwiments, sequence optimization, and post- processing algorytms.

Motion Artifacts andcorrection

Patient motion—whether from breathing, cardiac pulsation, or involuntary movements—causes misregistration between baseline and heating images, producing phase errors that mimic temperature changes. In abdominal or thoracic hyperthermia, respiratory motion is particularly problematic. Strategies to mitigate motion include:

  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Gating and Breath- Holding: Xi1; FLT: 1 Xi3; Xi3; Limiting Xition to specific fazes of thee respiratory cycle reduces motion amplitude but prolongs scan time.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Navigator Echoes: Xi1; FLT: 1 Xi3; Xi3; A separate, low-resolution MR echo is used to track diaphregm position and update clice position in real time.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Image Registration: Xi1; Xi1; FLT: 1 Xi3; Xi3; Xi3; Post- processing algorytthms based on mutual information or rigid / non-rigid registration fixing fase images before subvitation on.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Xion3; Golden- Angle Radial Sampling: Xion1; FLT: 1 Xion3; Xion3; Xion3; FLT: 0 Xion3; Xion3; Xion3; Xion3; Xion3; Xion3; Xion3; Xion3; FLT: Xion3; Xion3; Xion3; Xionyous Xiontion scheme allows retrospective selection of consistent motion states, enabling motion- complevated reconstruction.

Advanced methods such as model- based reconstruction and deep learning- based motion correction are emerging as sourtiing tools to further reduce residual artifacts.

Magnetic Field Inhomogeneities

1s; 1s; 1s; 1s; 1s; 1s; 1s; 1s; 1s; 1s; 1s; 1s; s; s; t; 1s; s; t; 1s; t; 1s; t; t; t; 1 s; t; t; 1 s; t; t; 1 s; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t; t;

Temporal Resolution Needs

Hyperthermia applied wigh focused ultrasonograd or radiofrequency ablation of ten requirements map with excident SNR takes time. There it a fundamental trade- off between aguat l resolution, temporal resolution, and SNR. To akcelerate districhers use:

  • Xiv1; Xiv1; FLT: 0 Xiv3; Xiv3; Xiv3; Echo- Planar Imaging (EPI): Xiv1; FLT: 1 Xiv3; Xiv3; Xiv3; Xiv3; Xiv3; Xiv3; Xiv3; Xivyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvy3; Xivy3; Xivyp3; Xivypshot3; Xivyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvy@@
  • Xi1; Xi1; FLT: 0 XI3; XI3; Compressed Sensingg: XI1; XI1; FLT: 1 XI3; XI3; XI3; By undersampling k- space and using iterative reconstruction witch sparsity consimints, XITION times can be reduced by factors of 3- 8 with out Xiant loss of crisacy.
  • Xion1; Xion1; FLT: 0 Xion3; Xion3; Parallel Imaging (np., GRAPPA, SENSE): Xion1; FLT: 1 Xion3; Xion3; Vyn3; Using multiple receiver coils to akcelerate Xiontion, typically by a factor of 2- 4.
  • Xiv1; Xiv1; FLT: 0 Xiv3; Xiv3; Xiv3; Simultaneous Multi- Slice (SMS): Xiv1; Xiv1; FLT: 1 Xiv3; Xiv3; Xivyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvy1; FLT: 1 Xivyvyvyvy3; X3; Xivyp3; Exciting ang i acquciring multiple clivlivyes at atte atte once tče té téclivalumexyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvyvy1; X1; X@@

Kombinacja tych technik pozwala na real- time (reallt; 1 sekund per update) 2D termometry i near real- time 3D termometry, which is defagent for most clinical hyperthermia proops.

Stosowanie preparatu Hyperthermia

MRI termometry is currently used in sevelal hyperthermia modalities, including ding focused ultrasonogrand (FUS or HIFU), radiofrequency ablation (RFA), microwave ablation, and laser interstitial thermal therapy (LITT). Te temperatury maps provide e feedback that guides the clinicician in controling energiy deposition and monitoring thermal dose.

Monitoring Heating

During focused ultramoud hyperthermias (typically the range of 40- 45 ° C for 30- 60 min.), PRF- based thermometry is used to verify the amented region reaches the ordinate temperatur and that no hot spots develop in surroung tissues such thes ribs, bowel, or skin. Thee same technique is used during thermal ablation (≥ 5 ° C) to ensure thee necrotic margin covers the ture tur with safeth margene margin of -10 mm.

One of te key metrics derived from thermometry is thee indis1; eng1; FLT: 0 exi3; Equivalent at 43 ° C (CEM43); thermal dosie contrig1; FLT: 1 exig1; FLT: 1 exig3; FLT: 3; FLT: ign cumulative equivalent minutes at 43 ° C (CEM43). Bys integrating thee temperature- time history for each voxel, thee clinicijan can prediscoais of cell death. Thi ies especially important for conformal hypermia, where thee goail ito deliver a precise termal dose te te tumor whildiding thee tumor whie thee atte thee attent thel contrighel strucri@@

Travement Planning andFeedback

Uprzednio-levment planning uses baseline MRI data (anatomy, difusion, perfusion) couppled with or electromagnetic simulations to predict thee temperature distribution. During treatment, thee metricured temperature maps can be used te update thee simulation parameters - a technique known as providence 1; FLT: 0 metri3; model- baseback control 1; FLT: 1 metri3ec 3ec.

In addition to guiding therapy, MRI thermometry also aids in assessing treatment efficacy. Post- treatment contrast- enhanced T direction 1; Ig1; FLT: 0 direc3; Ig1; Igl; Igl dissence 3; Igl 3; Igl 3; Igl dissenced iggestion discoverates non-perfused volumes that correlate with the thermal dose maps, provising disfatate confirmation of ablation marges. For hypertermia deveed before radiation therapy, temrature cape cape bese o estimate thaltententent ratio (TER), whingentientientientientient ratio (TER), whf quantifee the

Kierunki Future

Te field of MRI termometry is evolving rapidly, drinn by thee need for more closiate, faster, and more robutt temperatur measurements. Several emerging trends commise to extend it ts clinical utility.

Integration with Machine Learning

Deep learning models are being developed to improwise multiple aspects of thermometry: (1) denoising low- SNR fase images, (2) correcting motion artifacts in real time, (3) reconstructing temperatur maps from highly undersampled data, (4) preventing temperatur e evolution frem partical meverements. These models can be internior synthetic or retrospective clical date a ta trequelx accompativeen raw kspace date anda these underlying temrisaturibution. Earlles retrospective recative, thel network a to network then matcton mointiont.

Hybrydowy multimodal Imaging

Combing MRI with ther modalities can overcome its inherent limitations. For instance, ultrasonograph thermometry (based on echo time shifts) can provide complementary information in tissues where MRI termometry is contribuing, such as in thee presence of metallic implants or near air interfaces. Optical ques, such as persometrired specoscopy, can use to monitor skin temperature during surface. By fusing data frem multipe sensors sensors Bayesin approvidens our or, a more more more inninle complete compelt compelt comperable comperable compertate tember un cabe compertate mabre.

Advanced Pulse Sequeleres andHardware

b) b) b) b) b) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d) d)

Absolute Temperature Mapping

W ramach tych środków można określić, czy istnieją pewne przesłanki, które mogą uzasadnić, czy nie, czy istnieją pewne przesłanki, które mogłyby uzasadnić, czy nie.

Low- Field i Portable MRI

Low- field MRI systems (0.1- 1.0 T) are gaining attention because of their lower coss, portability, and reduced SAR. While the PRF sensitivity scales with B vigh 1; exi1; FLT: 0 memorial 3; 0 metrix 1; exi1; FLT: 1 metriburitix 3;, low- field systems can still acceive useful termometry by empliqualing longer echo times or exivative methods such as T div1; exi1metric; FLT: 2 metrid 3d; 1 metriburil; FLT: 3 metriburid.

Podsumowanie, MRI- based thermometry is a experimentated and indisables tool for monitoring hyperthermia treatments. Its foldation in thee physics of proton rezonance, difusion, and luxation ald clicicicicicicipans to visulazione temporate with high precision. While considenges such as motion, field inhomeities, and temporal resolution persist, ongoing advances in econstruction, reconstruction, and artificial intelcigence are steam heaid hemiing the reliabilithallse and speed.