Detection of Recurrent Prostate Cancer With 18F-Fluciclovine PET/MRI.

OBJECTIVE: Simultaneous PET/MRI combines soft-tissue contrast of MRI with high molecular sensitivity of PET in one session. The aim of this prospective study was to evaluate detection rates of recurrent prostate cancer by 18F-fluciclovine PET/MRI. METHODS: Patients with biochemical recurrence (BCR) or persistently detectable prostate specific antigen (PSA), were examined with simultaneous 18F-fluciclovine PET/MRI. Multiparametric MRI (mpMRI) and PET/MRI were scored on a 3-point scale (1-negative, 2-equivocal, 3-recurrence/metastasis) and detection rates (number of patients with suspicious findings divided by total number of patients) were reported. Detection rates were further stratified based on PSA level, PSA doubling time (PSAdt), primary treatment and inclusion criteria (PSA persistence, European Association of Urology (EAU) Low-Risk BCR and EAU High-Risk BCR). A detailed investigation of lesions with discrepancy between mpMRI and PET/MRI scores was performed to evaluate the incremental value of PET/MRI to mpMRI. The impact of the added PET acquisition on further follow-up and treatment was evaluated retrospectively. RESULTS: Among patients eligible for analysis (n=84), 54 lesions were detected in 38 patients by either mpMRI or PET/MRI. Detection rates were 41.7% for mpMRI and 39.3% for PET/MRI (score 2 and 3 considered positive). There were no significant differences in detection rates for mpMRI versus PET/MRI. Disease detection rates were higher in patients with PSA≥1ng/mL than in patients with lower PSA levels but did not differ between patients with PSAdt above versus below 6 months. Detection rates in patients with primary radiation therapy were higher than in patients with primary surgery. Patients categorized as EAU Low-Risk BCR had a detection rate of 0% both for mpMRI and PET/MRI. For 15 lesions (27.8% of all lesions) there was a discrepancy between mpMRI score and PET/MRI score. Of these, 10 lesions scored as 2-equivocal by mpMRI were changed to a more definite score (n=4 score 1 and n=6 score 3) based on the added PET acquisition. Furthermore, for 4 of 10 patients with discrepancy between mpMRI and PET/MRI scores, the added PET acquisition had affected the treatment choice. CONCLUSION: Combined 18F-fluciclovine PET/MRI can detect lesions suspicious for recurrent prostate cancer in patients with a range of PSA levels. Combined PET/MRI may be useful to select patients for appropriate treatment, but is of limited use at low PSA values or in patients classified as EAU Low-Risk BCR, and the clinical value of 18F-fluciclovine PET/MRI in this study was too low to justify routine clinical use.

Regional myocardial long-axis strain and strain rate measured by different tissue Doppler and speckle tracking echocardiography methods: a comparison with tagged magnetic resonance imaging.

AIMS: Compare four different echocardiographic methods, based on tissue Doppler imaging (TDI) and speckle tracking (ST) separately or combined, for long-axis strain and strain rate (SR) measurements, using magnetic resonance imaging (MRI) tagging as a reference. METHODS AND RESULTS: In 21 subjects (10 with myocardial infarction) peak systolic strain and systolic and early diastolic SR were measured by four different echo methods: (i) two-dimensional (2D) strain (B-mode); (ii) ST (custom software) of segment end-points (B-mode); (iii) similar to (ii), but combining ST with tissue Doppler tracking; (iv) strain from tissue Doppler velocity gradients (VG). Agreement with MRI tagging was better for strain than for SR. Ninety-five per cent limits of agreement were wider for the TDI-VG method, and 2D strain showed negative bias compared with MRI tagging and the other echo methods. Reproducibility was better for 2D strain than for MRI tagging and the other echo methods. CONCLUSION: ST alone or combined with TDI seems to be suitable for automated measurements of regional myocardial deformation. The study gives important information on the strengths and weaknesses of the different methods, which is important for further development to increase accuracy and applicability.

A new tissue Doppler method for examination of left ventricular rotation.

This paper introduces a new semiautomatic method for assessing regional left ventricular (LV) rotation that uses the velocity field provided by tissue Doppler imaging (TDI). Left ventricular end-systolic angle of twist estimated by the new method has been compared with rotation by magnetic resonance imaging (MRI) tagging, by 2-D speckle tracking echocardiography (STE) and by a TDI method using the velocity difference between the tangential points on the LV circumference in 21 human subjects. The new TDI method gave lower absolute values for end-systolic twist angle than MRI and STE (agreement -4.1 +/- 2.1 degrees and -2.5 +/- 4.0 degrees, respectively). The reproducibility of the new method was as good as for MRI and STE, but worse than the use of TDI velocities in tangential points. The present study has shown that TDI methods constitute useful alternatives to speckle tracking and MRI, and should be considered in future studies of LV twist and rotation.

Real-time simultaneous triplane contrast echocardiography gives rapid, accurate, and reproducible assessment of left ventricular volumes and ejection fraction: a comparison with magnetic resonance imaging.

OBJECTIVE: We sought to compare the feasibility, accuracy, and reproducibility of simultaneous triplane echocardiography for measurements of left ventricular (LV) volumes and ejection fraction (EF) with reference to magnetic resonance imaging (MRI). METHODS: Digital echocardiography recordings of apical LV views with and without intravenous contrast were collected from 53 consecutive patients with conventional 2-dimensional (2D) imaging and with simultaneous triplane imaging. MRI of multiple LV short-axis sections was performed with a 1.5-T scanner. Endocardial borders were manually traced, and LV volumes and EF from 2D biplane echocardiography and MRI were calculated by method of disks. On triplane data, a triangular mesh was constructed by 3-dimensional interpolation and volumes calculated by the divergence theorem. RESULTS: Triplane image acquisition was less time-consuming than 2D biplane. Precontrast feasibility was 72% for triplane and 82% for 2D biplane images, increasing to 98% and 100% with contrast, respectively. Bland-Altman analysis demonstrated LV volume underestimation by echocardiography versus MRI, which was significantly reduced by contrast and triplane imaging. The 95% limits of agreement for EF between echocardiography and MRI narrowed using triplane compared with 2D biplane (precontrast -12.5 to 6.7% vs -17.2 to 9.9%, and with contrast -7.1 to 5.8% vs -9.4 to 6.4%, respectively). At intraobserver and interobserver analysis of 20 patients, limits of agreement for EF narrowed with contrast triplane compared with 2D biplane. CONCLUSION: Simultaneous LV triplane imaging is feasible with simple and rapid image acquisition and volume analysis, and with contrast enhancement it gives accurate and reproducible LV EF measurements compared with MRI.