% \section{Data Acquisition}
% We ran our experiments on 8 human subjects, to evaluate the robustness and clinical applicability of the family of Deep Image Prior methods. Data acquisition was performed using Siemens 3T MRI scanners, each equipped with 20-channel cardiac coils to ensure optimal signal reception from the heart. The imaging protocol employed a segmented inversion-recovery gradient echo sequence specifically optimized for cardiac imaging, achieving an isotropic spatial resolution of 1.25 x 1.25 x 1.25 mm³ with volume coverage ranging from 64 to 140 slices. Key sequence parameters were carefully selected to balance image quality and acquisition time, with a Repetition Time (TR) of 2.7 ms and Echo Time (TE) of 1.5 ms. For each subject, the Inversion Time (TI) was individually determined using a dedicated TI scout sequence to ensure optimal myocardial nulling and maximize contrast between healthy myocardium and areas of enhancement.

% To address the challenges of cardiac and respiratory motion, we implemented several motion compensation strategies. Data acquisition was synchronized with the patient's ECG, specifically targeting the diastolic phase when cardiac motion is minimal. A one-dimensional navigator was strategically positioned at the liver-diaphragm interface to monitor respiratory motion patterns. The number of phase-encoding lines acquired per heartbeat was dynamically adjusted based on individual heart rates, striking an optimal balance between acquisition efficiency and motion artifact reduction.

% The 3D k-space acquisition employed a spiral-like variable density pattern on a Cartesian grid. We implemented strong oversampling in the central ky-kz region to maintain contiguous dense sampling in the ky-kz center for any data subset, while pseudo-randomly sampling the peripheral ky-kz plane. The sampling pattern incorporated golden ratio-based angular and radial spacing and operated independently of the navigator position. This design choice produced incoherent artifacts during undersampling, making them less visually disruptive and easier to remove during reconstruction. Additionally, the golden ratio properties of the sampling pattern ensured robust performance even in the presence of motion or interrupted scanning.

% For each subject, we acquired both full-time (approximately 10 minutes) and accelerated (approximately 2-4 minutes) datasets to enable comparative analysis of reconstruction quality across different temporal resolutions. All acquisitions were performed following protocols approved by the institutional review board, with informed consent obtained from all participants. This dataset provides a robust foundation for evaluating the effectiveness of our proposed reconstruction methods in a clinically relevant context.

\section{Data Acquisition}
We evaluated our methods on data from 10 human subjects acquired using Siemens 3T MRI scanners with 20-channel cardiac coils. The imaging protocol used a segmented inversion-recovery gradient echo sequence optimized for cardiac imaging, achieving an isotropic 1.25 mm$^3$ resolution with 64-140 axial slices. Sequence parameters included TR = 2.7 ms, TE = 1.5 ms, with individually optimized Inversion Time (TI) determined via a TI scout sequence for optimal myocardial nulling.
Motion compensation was implemented through ECG-gating that targets the diastolic phase and a one-dimensional navigator at the liver-diaphragm interface. 
% The number of phase-encoding lines per heartbeat was dynamically adjusted based on heart rate to balance acquisition efficiency and motion artifacts \cite{basha2017clinical}.
The number of phase-encoding lines was picked at the start of the acquisition based on the heartrate.

For our isotropic acquisitions, the K-space data was collected continuously regardless of the navigator position. The 3D K-space was filled using a spiral-like variable density sampling pattern with golden ratio-based angular and radial spacing, with strong oversampling in the central ky-kz region. All acquisitions followed institutional review board-approved protocols with informed consent. This dataset allows evaluation of reconstruction quality at different acceleration rates while maintaining the challenging conditions of clinical cardiac imaging.