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Since the publication of the European Association of Nuclear Medicine (EANM) procedural guidelines for radionuclide myocardial perfusion imaging (MPI) in 2005, many small and some larger steps of progress have been made, improving MPI procedures. In this paper, the major changes from the updated 2015 procedural guidelines are highlighted, focusing on the important changes related to new instrumentation with improved image information and the possibility to reduce radiation exposure, which is further discussed in relation to the recent developments of new International Commission on Radiological Protection (ICRP) models. Introduction of the selective coronary vasodilator regadenoson and the use of coronary CT-contrast agents for hybrid imaging with SPECT/CT angiography are other important areas for nuclear cardiology that were not included in the previous guidelines. A large number of minor changes have been described in more detail in the fully revised version available at the EANM home page: https://eanm.org/wp-content/uploads/2025/04/2015_myocardial_perfusion.pdf .

Objective To determine the accuracy of iodine quantification with dual energy computed tomography (DECT) in two high-end CT systems with different spectral imaging techniques. Methods Five tubes with different iodine concentrations (0, 5, 10, 15, 20 mg/ml) were analysed in an anthropomorphic thoracic phantom. Adding two phantom rings simulated increased patient size. For third-generation dual source CT (DSCT), tube voltage combinations of 150Sn and 70, 80, 90, 100 kVp were analysed. For dual layer CT (DLCT), 120 and 140 kVp were used. Scans were repeated three times. Median normalized values and interquartile ranges (IQRs) were calculated for all kVp settings and phantom sizes. Results Correlation between measured and known iodine concentrations was excellent for both systems ( R  = 0.999–1.000, p  < 0.0001). For DSCT, median measurement errors ranged from −0.5% (IQR −2.0, 2.0%) at 150Sn/70 kVp and −2.3% (IQR −4.0, −0.1%) at 150Sn/80 kVp to −4.0% (IQR −6.0, −2.8%) at 150Sn/90 kVp. For DLCT, median measurement errors ranged from −3.3% (IQR −4.9, −1.5%) at 140 kVp to −4.6% (IQR −6.0, −3.6%) at 120 kVp. Larger phantom sizes increased variability of iodine measurements ( p  < 0.05). Conclusion Iodine concentration can be accurately quantified with state-of-the-art DECT systems from two vendors. The lowest absolute errors were found for DSCT using the 150Sn/70 kVp or 150Sn/80 kVp combinations, which was slightly more accurate than 140 kVp in DLCT. Key Points • High - end CT scanners allow accurate iodine quantification using different DECT techniques . • Lowest measurement error was found in scans with largest photon energy separation . • Dual - source CT quantified iodine slightly more accurately than dual layer CT .

PurposeSingle-photon emission computed tomography (SPECT) combined with computed tomography (CT) was introduced as a hybrid SPECT/CT imaging modality two decades ago. The main advantage of SPECT/CT is the increased specificity achieved through a more precise localization and characterization of functional findings. The improved diagnostic accuracy is also associated with greater diagnostic confidence and better inter-specialty communication.MethodsThis review presents a critical assessment of the relevant literature published so far on the role of SPECT/CT in a variety of clinical conditions. It also includes an update on the established evidence demonstrating both the advantages and limitations of this modality.ConclusionsFor the majority of applications, SPECT/CT should be a routine imaging technique, fully integrated into the clinical decision-making process, including oncology, endocrinology, orthopaedics, paediatrics, and cardiology. Large-scale prospective studies are lacking, however, on the use of SPECT/CT in certain clinical domains such as neurology and lung disorders. The review also presents data on the complementary role of SPECT/CT with other imaging modalities and a comparative analysis, where available.

Quantification of myocardial blood flow requires knowledge of the amount of contrast agent in the myocardial tissue and the arterial input function (AIF) driving the delivery of this contrast agent. Accurate quantification is challenged by the lack of linearity between the measured signal and contrast agent concentration. This work characterizes sources of non-linearity and presents a systematic approach to accurate measurements of contrast agent concentration in both blood and myocardium. A dual sequence approach with separate pulse sequences for AIF and myocardial tissue allowed separate optimization of parameters for blood and myocardium. A systems approach to the overall design was taken to achieve linearity between signal and contrast agent concentration. Conversion of signal intensity values to contrast agent concentration was achieved through a combination of surface coil sensitivity correction, Bloch simulation based look-up table correction, and in the case of the AIF measurement, correction of T2* losses. Validation of signal correction was performed in phantoms, and values for peak AIF concentration and myocardial flow are provided for 29 normal subjects for rest and adenosine stress. For phantoms, the measured fits were within 5% for both AIF and myocardium. In healthy volunteers the peak [Gd] was 3.5 ± 1.2 for stress and 4.4 ± 1.2 mmol/L for rest. The T2* in the left ventricle blood pool at peak AIF was approximately 10 ms. The peak-to-valley ratio was 5.6 for the raw signal intensities without correction, and was 8.3 for the look-up-table (LUT) corrected AIF which represents approximately 48% correction. Without T2* correction the myocardial blood flow estimates are overestimated by approximately 10%. The signal-to-noise ratio of the myocardial signal at peak enhancement (1.5 T) was 17.7 ± 6.6 at stress and the peak [Gd] was 0.49 ± 0.15 mmol/L. The estimated perfusion flow was 3.9 ± 0.38 and 1.03 ± 0.19 ml/min/g using the BTEX model and 3.4 ± 0.39 and 0.95 ± 0.16 using a Fermi model, for stress and rest, respectively. A dual sequence for myocardial perfusion cardiovascular magnetic resonance and AIF measurement has been optimized for quantification of myocardial blood flow. A validation in phantoms was performed to confirm that the signal conversion to gadolinium concentration was linear. The proposed sequence was integrated with a fully automatic in-line solution for pixel-wise mapping of myocardial blood flow and evaluated in adenosine stress and rest studies on N = 29 normal healthy subjects. Reliable perfusion mapping was demonstrated and produced estimates with low variability.

Pulsatile blood flow through the cavities of the heart and great vessels is time-varying and multidirectional. Access to all regions, phases and directions of cardiovascular flows has formerly been limited. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has enabled more comprehensive access to such flows, with typical spatial resolution of 1.5×1.5×1.5 – 3×3×3 mm 3 , typical temporal resolution of 30–40 ms, and acquisition times in the order of 5 to 25 min. This consensus paper is the work of physicists, physicians and biomedical engineers, active in the development and implementation of 4D Flow CMR, who have repeatedly met to share experience and ideas. The paper aims to assist understanding of acquisition and analysis methods, and their potential clinical applications with a focus on the heart and greater vessels. We describe that 4D Flow CMR can be clinically advantageous because placement of a single acquisition volume is straightforward and enables flow through any plane across it to be calculated retrospectively and with good accuracy. We also specify research and development goals that have yet to be satisfactorily achieved. Derived flow parameters, generally needing further development or validation for clinical use, include measurements of wall shear stress, pressure difference, turbulent kinetic energy, and intracardiac flow components. The dependence of measurement accuracy on acquisition parameters is considered, as are the uses of different visualization strategies for appropriate representation of time-varying multidirectional flow fields. Finally, we offer suggestions for more consistent, user-friendly implementation of 4D Flow CMR acquisition and data handling with a view to multicenter studies and more widespread adoption of the approach in routine clinical investigations.

BackgroundWe measured myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) by a dynamic low-dose CZT-SPECT protocol in patients with suspected or known coronary artery disease (CAD) and investigated the capability of dynamic data in predicting obstructive CAD. A total of 173 patients with suspected or known CAD underwent dynamic CZT-SPECT after the injection of 155 MBq and 370 MBq of 99mTc-sestamibi for rest and stress imaging, respectively. Standard rest and stress imaging were performed at the end of each dynamic scan. A total perfusion defect (TPD) < 5% were considered normal. Obstructive CAD was defined as ≥ 70% stenosis at coronary angiography.ResultsGlobal MPR was lower (p < 0.05) in patients with abnormal compared with those with normal MPI (2.40 ± 0.7 vs. 2.70 ± 0.8). A weak, albeit significant correlation between TPD and MPR (r = − 0.179, p < 0.05) was found. In 91 patients with available angiographic data, hyperemic MBF (2.59 ± 1.2 vs. 3.24 ± 1.1 ml/min/g) and MPR (1.96 ± 0.7 vs. 2.74 ± 0.9) were lower (both p < 0.05) in patients with obstructive CAD (n = 21) compared with those without (n = 70). At univariable analysis, TPD, hyperemic MBF, and MPR were significant predictors of obstructive CAD, whereas only MPR was independent predictor at multivariable analysis (p < 0.05). At per vessels analysis, regional hyperemic MBF (2.59 ± 1.2 vs. 3.24 ± 1.1 ml/min/g) and regional MPR (1.96 ± 0.7 vs. 2.74 ± 0.9) were lower in the 31 vessels with obstructive CAD compared with 242 vessels without (both p < 0.05).ConclusionsIn patients with suspected or known CAD, MPR assessed by low-dose dynamic CZT-SPECT showed a good correlation with myocardial perfusion imaging findings and it could be useful to predict obstructive CAD.

Purpose To evaluate the quality of lung perfusion imaging obtained with photon-counting-detector CT (PCD-CT) in comparison with dual-source, dual-energy CT (DECT). Methods Seventy-one consecutive patients scanned with PCD-CT were compared to a paired population scanned with dual-energy on a 3rd-generation DS-CT scanner using (a) for DS-CT (Group 1): collimation: 64 × 0.6 × 2 mm; pitch: 0.55; (b) for PCD-CT (Group 2): collimation: 144 × 0.4 mm; pitch: 1.5; single-source acquisition. The injection protocol was similar in both groups with the reconstruction of perfusion images by subtraction of high- and low-energy virtual monoenergetic images. Results Compared to Group 1, Group 2 examinations showed: (a) a shorter duration of data acquisition (0.93 ± 0.1 s vs 3.98 ± 0.35 s; p  < 0.0001); (b) a significantly lower dose-length-product (172.6 ± 55.14 vs 339.4 ± 75.64 mGy·cm; p  < 0.0001); and (c) a higher level of objective noise ( p  < 0.0001) on mediastinal images. On perfusion images: (a) the mean level of attenuation did not differ ( p  = 0.05) with less subjective image noise in Group 2 ( p  = 0.049); (b) the distribution of scores of fissure visualization differed between the 2 groups ( p  < 0.0001) with a higher proportion of fissures sharply delineated in Group 2 ( n  = 60; 84.5% vs n  = 26; 26.6%); (c) the rating of cardiac motion artifacts differed between the 2 groups ( p  < 0.0001) with a predominance of examinations rated with mild artifacts in Group 2 ( n  = 69; 97.2%) while the most Group 1 examinations showed moderate artifacts ( n  = 52; 73.2%). Conclusion PCD-CT acquisitions provided similar morphologic image quality and superior perfusion imaging at lower radiation doses. Clinical relevance statement The improvement in the overall quality of perfusion images at lower radiation doses opens the door for wider applications of lung perfusion imaging in clinical practice. Key Points The speed of data acquisition with PCD-CT accounts for mild motion artifacts . Sharply delineated fissures are depicted on PCD-CT perfusion images . High-quality perfusion imaging was obtained with a 52% dose reduction .

Pseudo-continuous arterial spin labeling (PCASL) MRI has become a popular tool for non-invasive perfusion imaging and angiography. However, it suffers from sensitivity to off-resonance effects within the labeling plane, which can be exacerbated at high field or in the presence of metallic implants, leading to spatially varying signal loss and cerebral blood flow underestimation. In this work we propose a prospective correction technique based on the optimized encoding scheme, which allows the rapid calculation of transverse gradient blips and RF phase modulations that best cancel phase offsets due to off-resonance at the locations of the feeding arteries within the labeling plane. This calculation is based upon a rapidly acquired single-slice fieldmap and is applicable to any number and arrangement of arteries. In addition, this approach is applicable to both conventional PCASL and a vessel-selective variant known as vessel-encoded PCASL (VEPCASL). Through simulations and experiments in healthy volunteers it was shown that in the presence of off-resonance effects a strong bias in the strength of the perfusion signal across vascular territories can be introduced, the signal-to-noise ratio (SNR) efficiency of PCASL and VEPCASL can be severely compromised (∼40% reduction in vivo), and that vessel-selective signal in VEPCASL can be incorrectly assigned. Distortion of the spatial regions placed in the label or control conditions in the presence of off-resonance effects was confirmed in phantom experiments. The application of the proposed correction restored SNR efficiency to levels present in the absence of off-resonance effects and corrected errors in the vascular territory maps derived from VEPCASL. Due to the rapid nature of the required calculations and fieldmap acquisition, this approach could be inserted into protocols with minimal effect on the total scan time.

Differences in the performance of cadmium-zinc-telluride (CZT) cameras or collimation systems that have recently been commercialized for myocardial SPECT remain unclear. In the present study, the performance of 3 of these systems was compared by a comprehensive analysis of phantom and human SPECT images. We evaluated the Discovery NM 530c and DSPECT CZT cameras, as well as the Symbia Anger camera equipped with an astigmatic (IQ x SPECT) or parallel-hole (conventional SPECT) collimator. Physical performance was compared on reconstructed SPECT images from a phantom and from comparable groups of healthy subjects. Classifications were as follows, in order of performance. For count sensitivity on cardiac phantom images (counts x s(-1) x MBq(-1)), DSPECT had a sensitivity of 850; Discovery NM 530c, 460; IQ x SPECT, 390; and conventional SPECT, 130. This classification was similar to that of myocardial counts normalized to injected activities from human images (respective mean values, in counts x s(-1) x MBq(-1): 11.4 ± 2.6, 5.6 ± 1.4, 2.7 ± 0.7, and 0.6 ± 0.1). For central spatial resolution: Discovery NM 530c was 6.7 mm; DSPECT, 8.6 mm; IQ x SPECT, 15.0 mm; and conventional SPECT, 15.3 mm, also in accordance with the analysis of the sharpness of myocardial contours on human images (in cm(-1): 1.02 ± 0.17, 0.92 ± 0.11, 0.64 ± 0.12, and 0.65 ± 0.06, respectively). For contrast-to-noise ratio on the phantom: Discovery NM 530c had a ratio of 4.6; DSPECT, 4.1; IQ x SPECT, 3.9; and conventional SPECT, 3.5, similar to ratios documented on human images (5.2 ± 1.0, 4.5 ± 0.5, 3.9 ± 0.6, and 3.4 ± 0.3, respectively). The performance of CZT cameras is dramatically higher than that of Anger cameras, even for human SPECT images. However, CZT cameras differ in that spatial resolution and contrast-to-noise ratio are better with the Discovery NM 530c, whereas count sensitivity is markedly higher with the DSPECT.