scholarly journals Effect of PET-CT misalignment on the quantitative accuracy of cardiac 15O-water PET

2020 ◽  
Author(s):  
Jonny Nordström ◽  
Hendrik J. Harms ◽  
Tanja Kero ◽  
Maryam Ebrahimi ◽  
Jens Sörensen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Left Ventricle ◽  
Ct Scans ◽  
Global Level ◽  
Average Absolute Deviation ◽  
Absolute Deviation ◽  
Quantitative Accuracy ◽  
Pet Ct ◽  
A Minor ◽  
Minor Extent

Abstract Background Quantification of myocardial blood flow (MBF) with PET requires accurate attenuation correction, which is performed using a separate CT. Misalignment between PET and CT scans has been reported to be a common problem. The purpose of the present study was to assess the effect of PET CT misalignment on the quantitative accuracy of cardiac 15O-water PET. Methods Ten clinical patients referred for evaluation of ischemia and assessment of MBF with 15O-water were included in the study. Eleven different misalignments between PET and CT were induced in 6 different directions with 10 and 20 mm amplitudes: caudal (+Z), cranial (− Z), lateral (±X), anterior (+Y), and anterior combined with cranial (+ Y and − Z). Blood flow was quantified from rates of washout (MBF) and uptake (transmural MBF, MBFt) for the whole left ventricle and the three coronary territories. The results from all misalignments were compared to the original scan without misalignment. Results MBF was only minorly affected by misalignments, but larger effects were seen in MBFt. On the global level, average absolute deviation across all misalignments for MBF was 1.7% ± 1.4% and for MBFt 5.4% ± 3.2 Largest deviation for MBF was − 4.8% ± 5.8% (LCX, X + 20) and for MBFt − 19.3% ± 9.6% (LCX, X + 20). In general, larger effects were seen in LAD and LCX compared to in RCA. Conclusion The quantitative accuracy of MBF from 15O-water PET, based on the washout of the tracer, is only to a minor extent affected by misalignment between PET and CT.

The Value of PET-CT Scans in Patients with Ventricular Assist Devices

2016 ◽  
Vol 64 (S 01) ◽  
Author(s):  
A. Bernhardt ◽  
M. Barten ◽  
A. Schäfer ◽  
B. Sill ◽  
F. Wagner ◽  
...  
Keyword(s):  
Ventricular Assist Devices ◽  
Ct Scans ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Pet Ct

Numerical simulation of pulsatile blood flow in the human left ventricle

2007 ◽  
Vol 55 (S 1) ◽  
Author(s):  
W Schiller ◽  
K Spiegel ◽  
T Schmid ◽  
H Rudorf ◽  
S Flacke ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Blood Flow ◽  
Left Ventricle ◽  
Pulsatile Blood Flow ◽  
Human Left Ventricle

scholarly journals Influence of patient motion on quantitative accuracy in cardiac 15O-water positron emission tomography

2021 ◽  
Author(s):  
Jonny Nordström ◽  
Hendrik J. Harms ◽  
Tanja Kero ◽  
Jens Sörensen ◽  
Mark Lubberink
Keyword(s):  
Motion Detection ◽  
Detection Algorithm ◽  
Clinical Effects ◽  
Average Deviation ◽  
Patient Motion ◽  
Motion Data ◽  
Positron Emission ◽  
Quantitative Accuracy ◽  
Pet Ct ◽  
Using Data

Abstract Background Patient motion is a common problem during cardiac PET. The purpose of the present study was to investigate to what extent motions influence the quantitative accuracy of cardiac 15O-water PET/CT and to develop a method for automated motion detection. Method Frequency and magnitude of motion was assessed visually using data from 50 clinical 15O-water PET/CT scans. Simulations of 4 types of motions with amplitude of 5 to 20 mm were performed based on data from 10 scans. An automated motion detection algorithm was evaluated on clinical and simulated motion data. MBF and PTF of all simulated scans were compared to the original scan used as reference. Results Patient motion was detected in 68% of clinical cases by visual inspection. All observed motions were small with amplitudes less than half the LV wall thickness. A clear pattern of motion influence was seen in the simulations with a decrease of myocardial blood flow (MBF) in the region of myocardium to where the motion was directed. The perfusable tissue fraction (PTF) trended in the opposite direction. Global absolute average deviation of MBF was 3.1% ± 1.8% and 7.3% ± 6.3% for motions with maximum amplitudes of 5 and 20 mm, respectively. Automated motion detection showed a sensitivity of 90% for simulated motions ≥ 10 mm but struggled with the smaller (≤ 5 mm) simulated (sensitivity 45%) and clinical motions (accuracy 48%). Conclusion Patient motion can impair the quantitative accuracy of MBF. However, at typically occurring levels of patient motion, effects are similar to or only slightly larger than inter-observer variability, and downstream clinical effects are likely negligible.

Malignes Melanom

2021 ◽  
Vol 12 (01) ◽  
pp. 48-48
Author(s):  
Ine Schmale
Keyword(s):  
Fdg Pet ◽  
Malignes Melanom ◽  
Ct Scans ◽  
Pet Ct ◽  
Fdg Pet Ct

In einer multizentrischen Studie wurde untersucht, ob mithilfe eines FDG-PET-CT-Scans die Entscheidung zum Beenden der Therapie mit Checkpoint-Inhibitoren möglicherweise verbessert werden kann.

scholarly journals Optimization of SPECT/CT imaging protocols for quantitative and qualitative 99mTc SPECT

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Dennis Kupitz ◽  
Heiko Wissel ◽  
Jan Wuestemann ◽  
Stephanie Bluemel ◽  
Maciej Pech ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Quantitative Imaging ◽  
Scatter Correction ◽  
Reconstruction Algorithm ◽  
Weighting Factor ◽  
Quantitative Spect ◽  
Pet Ct ◽  
Spect Acquisition ◽  
The Mean ◽  
A Minor

Abstract Background The introduction of hybrid SPECT/CT devices enables quantitative imaging in SPECT, providing a methodological setup for quantitation using SPECT tracers comparable to PET/CT. We evaluated a specific quantitative reconstruction algorithm for SPECT data using a 99mTc-filled NEMA phantom. Quantitative and qualitative image parameters were evaluated for different parametrizations of the acquisition and reconstruction protocol to identify an optimized quantitative protocol. Results The reconstructed activity concentration (ACrec) and the signal-to-noise ratio (SNR) of all examined protocols (n = 16) were significantly affected by the parametrization of the weighting factor k used in scatter correction, the total number of iterations and the sphere volume (all, p < 0.0001). The two examined SPECT acquisition protocols (with 60 or 120 projections) had a minor impact on the ACrec and no significant impact on the SNR. In comparison to the known AC, the use of default scatter correction (k = 0.47) or object-specific scatter correction (k = 0.18) resulted in an underestimation of ACrec in the largest sphere volume (26.5 ml) by − 13.9 kBq/ml (− 16.3%) and − 7.1 kBq/ml (− 8.4%), respectively. An increase in total iterations leads to an increase in estimated AC and a decrease in SNR. The mean difference between ACrec and known AC decreased with an increasing number of total iterations (e.g., for 20 iterations (2 iterations/10 subsets) = − 14.6 kBq/ml (− 17.1%), 240 iterations (24i/10s) = − 8.0 kBq/ml (− 9.4%), p < 0.0001). In parallel, the mean SNR decreased significantly from 2i/10s to 24i/10s by 76% (p < 0.0001). Conclusion Quantitative SPECT imaging is feasible with the used reconstruction algorithm and hybrid SPECT/CT, and its consistent implementation in diagnostics may provide perspectives for quantification in routine clinical practice (e.g., assessment of bone metabolism). When combining quantitative analysis and diagnostic imaging, we recommend using two different reconstruction protocols with task-specific optimized setups (quantitative vs. qualitative reconstruction). Furthermore, individual scatter correction significantly improves both quantitative and qualitative results.

Benefit of Static FET PET in Pretreated Pediatric Brain Tumor Patients with Equivocal Conventional MRI Results

2021 ◽  
Author(s):  
Frederik Grosse ◽  
Florian Wedel ◽  
Ulrich-Wilhelm Thomale ◽  
Ingo Steffen ◽  
Arend Koch ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Tumor Tissue ◽  
Pediatric Brain Tumor ◽  
Ct Scans ◽  
Tumor Patients ◽  
Fet Pet ◽  
Conventional Mri ◽  
Pet Ct ◽  
Pediatric Brain

Abstract Background MRI has shortcomings in differentiation between tumor tissue and post-therapeutic changes in pretreated brain tumor patients. Patients We assessed 22 static FET-PET/CT-scans of 17 pediatric patients (median age 12 years, range 2–16 years, ependymoma n=4, medulloblastoma n=4, low-grade glioma n=6, high-grade glioma n=3, germ cell tumor n=1, choroid plexus tumor n=1, median follow-up: 112 months) with multimodal treatment. Method FET-PET/CT-scans were analyzed visually by 3 independent nuclear medicine physicians. Additionally quantitative FET-Uptake for each lesion was determined by calculating standardized uptake values (SUVmaxT/SUVmeanB, SUVmeanT/SUVmeanB). Histology or clinical follow-up served as reference. Results Static FET-PET/CT reliably distinguished between tumor tissue and post-therapeutic changes in 16 out of 17 patients. It identified correctly vital tumor tissue in 13 patients and post-therapeutic changes in 3 patients. SUV-based analyses were less sensitive than visual analyses. Except from a choroid plexus carcinoma, all tumor entities showed increased FET-uptake. Discussion Our study comprises a limited number of patients but results corroborate the ability of FET to detect different brain tumor entities in pediatric patients and discriminate between residual/recurrent tumor and post-therapeutic changes. Conclusions We observed a clear benefit from additional static FET-PET/CT-scans when conventional MRI identified equivocal lesions in pretreated pediatric brain tumor patients. These results warrant prospective studies that should include dynamic scans.

scholarly journals Not All That Shines on a PET Scan Is Cancer: A Silicone-Induced Granuloma Masquerading as Malignancy

2020 ◽  
Vol 11 (1) ◽  
pp. 8-12
Author(s):  
Krishna Vedala ◽  
Philip Sobash ◽  
Deborah Johnson ◽  
Krishna Kakkera
Keyword(s):  
Pet Scan ◽  
Imaging Modalities ◽  
Ct Scans ◽  
Pet Ct ◽  
Suspicious Lesions

PET/CT scans are frequently used in the initial workup of suspicious lesions but not all that lights up on a PET is cancerous. We wish to discuss a case of silicone-induced granuloma mimicking malignancy and the role of other imaging modalities for further workup.

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