Criteria for the addition of prone imaging to myocardial perfusion single-photon emission computed tomography for inferior wall

Attenuation correction in CZT myocardial perfusion imaging comparison of supine-prone and low-dose CT-corrected supine acquisitions

AIMS

The study aimed to investigate whether additional prone imaging delivers comparable results to supine imaging with low-dose computed tomography (CT) attenuation correction (CTAC) in cadmium, zinc and telluride (CZT) myocardial perfusion imaging.

METHODS AND RESULTS

Thirty-four patients with an indication for myocardial perfusion imaging were studied with a CZT camera in the supine and then prone position. Furthermore, a low-dose CT was acquired. Three data sets were reconstructed and considered for analysis: (1) supine CZT, (2) supine CZT with CTAC and (3) supine CZT with additional prone CZT. Based on 17-segment polartomograms, we compared radiopharmaceutical uptake percentage, summed stress score (SSS), summed rest score (SRS), summed difference score (SDS), total ischemic and scarred segments, and finally scan classification and clinical decision-making. SSS of supine/supine-CTAC/supine-prone was 341/229/253 (P < 0.05), SRS was 246/156/164 (P < 0.05) and SDS was 104/88/96 (ns), respectively. Total ischemic segments were 65/67/65 (ns) and total scarred segments 96/62/69 (P < 0.05), respectively. The frequency of normal scans was highest for supine-prone, followed by supine-CTAC and supine (41/35/24%, respectively). Supine imaging indicated 23% of patients for invasive coronary angiography, both supine-CTAC and supine-prone 18%. These two showed a significant intercorrelation.

CONCLUSION

Additional prone imaging and CTAC are mainly correct for the amount and extent of myocardial scars. Both methods increase the frequency of normal scans and show a significant agreement in clinical decision-making. Additional prone imaging appears as a useful alternative when a low-dose CT for attenuation correction is not available.

Imaging technology for myocardial perfusion single-photon emission computed tomography 2018 in Japan

AIM

Recently, nuclear cardiology has dramatically advanced by a new technology development such as the device, short-term acquisition system, image reconstruction algorithm and image analysis. Although these innovations have been gradually employed in routine examinations, we did not investigate the current use of image acquisition, image reconstruction, and image analysis with myocardial perfusion single-photon emission computed tomography (MPS). We investigated the current status of MPS imaging technology in Japan.

METHODS

We carried out a survey using a Web-based questionnaire system, the opening of which was announced via e-mail, and it was available on a website for 3 months. We collected data on the current use of MPS with ²⁰¹Tl and/or ^99mTc agents with respect to routine protocols, image acquisition, image reconstruction, and image analysis.

RESULTS

We received responses to the Web-based questionnaire from 178 and 174 people for ^99mTc and ²⁰¹Tl MPS, respectively. The routine protocols of MPS of stress-rest and rest-stress MPS on 1-day protocols with ^99mTc were 41.2% and 14.5%, respectively, and the rest-only scan response rate was 23.7%, whereas that of ²⁰¹Tl MPS was 65.9% with stress-rest MPS, 19.0% with rest-only MPS, and 10.9% with stress-rest MPS adding a rest scan 24 h after injection. The filtered back projection (FBP) method is most commonly used image reconstruction method, yielding 70.5% for ^99mTc MPS and 76.8% for ²⁰¹Tl MPS, including combined FBP and ordered subset expectation maximization method. The results for no-correction (NC) images were 49.2% with ^99mTc MPS and 55.2% with ²⁰¹Tl MPS including the response of NC and combined attenuation correction (AC) and scatter correction (SC) (i.e., ACSC) images. The AC or ACSC images of ^99mTc and ²⁰¹Tl were provided by 30-40% of the institutions surveyed.

CONCLUSIONS

We investigated the current status of MPS imaging technology in Japan, and found that although the use of various technical developments has been reported, some of these technologies have not been utilized effectively. Hence, we expect that nuclear medicine technology will be used more effectively to improve diagnosis.

Assessment of Myocardial CZT SPECT Recording in a Forward-Leaning Bikerlike Position

This prospective randomized study assessed myocardial perfusion imaging with the high-sensitivity D.SPECT cadmium-zinc-telluride camera in a forward-leaning bikerlike position, which may potentially lower diaphragmatic attenuation and reduce breathing-related cardiac motion, in a manner comparable to the prone position proposed with other SPECT cameras. Methods: Patients referred for a stress-rest 99mTc-sestamibi protocol and positioned in the biker position, with the chest leaning forward on the D.SPECT camera-head at 35° from vertical, had an additional resting D.SPECT recording in the supine position (n = 40) or in the sitting position with the back rearward at 30° from vertical (n = 40). Segments with attenuation artifacts were defined as those with less than 65% uptake but with strictly normal contractility at gated SPECT and no defect reversibility from stress images. Results: The biker position was associated with lower heart-to-detector distances than the supine or sitting positions (both P < 0.001); lower cardiac motion amplitudes, assessed on panograms, than the supine position (P < 0.001); and fewer segments with attenuation artifacts than the supine position (on average, 1.10 ± 1.01 vs. 1.90 ± 1.74, P = 0.010) or the sitting position (0.75 ± 0.93 vs. 1.38 ± 1.60, P = 0.011). Conclusion: Myocardial perfusion images from D.SPECT are enhanced for patients positioned in a forward-leaning bikerlike position comparatively to sitting or supine positions, with a notably lower rate of attenuation artifacts.