Myocardial perfusion SPECT 2015 in Germany. Results of the 7th survey

Myocardial Perfusion SPECT and ATTR imaging 2021 in Germany: Results of the 9th Survey

AIM

This paper presents the results of the 9th survey of myocardial perfusion SPECT (MPS) from the reporting year 2021.

METHODS

218 questionnaires (131 practices (PR), 58 hospitals (HO), 29 university hospitals (UH)) were evaluated. Results of the last survey 2018 are set in squared brackets.

RESULTS

MPS data from a total of 133,057 [145,930] patients (-8.8%) with 131,868 [143,707] stress and 106,546 [121,899] rest MPS were analysed. A comparison with official data revealed that 54% all MPS were recorded. From 2018 to 2021, official data showed a every year an increase in MPS numbers. On average, 610 [502] MPS patients (+22%) were examined in each department. 74% [69%] of the responders reported an increase or no changes in their MPS patient numbers. Ambulatory care cardiologists represented as always, the mayor referral group (68% [69%]). For the first time, pharmacological stress was more frequently applied than ergometry (42% [51]). Regadenoson was mostly used. The use of the different protocols remained nearly unchanged. Two-day protocols were predominantly applied (49% [48%]). A shift from multi-headed cameras (58% [72%]) to SPECT-CT systems (24% [17%]) was found. Attenuation correction was performed in 33% [26%] of all MPS. 88% [86%] of all stress, 88% [87%] of all rest and 87% [83%] of all stress and rest MPS were acquired as gated SPECT. 72% [67%] of all departments performed scoring by default. The number of departments without scoring decreased to 13% [16%].

CONCLUSIONS

The MPS Study 2021 shows that the long-term positive development of MPS imaging in Germany is continuing. The COVID-19 pandemia did not change this trend. The procedural and technical details of MPS imaging reveal a high level of guideline conformity.

Myocardial perfusion SPECT in Germany from 2012 to 2021: insights into development and quality indicators

PURPOSE

This paper summarises the results of 4 national surveys on the numbers, utilisation and technique of myocardial perfusion SPECT (MPS) from 2012 to 2021.

METHODS

A one-page questionnaire for information on MPS in 2012, 2015, 2018 and 2021 was sent to German centres practising nuclear medicine. To check for representativeness, the numbers obtained were related to official annual data and furthermore to the numbers of invasive coronary angiography procedures (ICA).

RESULTS

MPS examinations increased by > 40% from 2012 to 2021 and showed a centralisation with increasing MPS per centre. In 2020, a mild impact of the COVID-19 pandemic could be observed in the form of only a slight MPS increase, which was compensated in the following year. Outpatient care cardiologists represent the most important referrer (70%). Mostly, 2-day protocols were used. One-day protocols and stress-only protocols showed insignificant changes. The use of exercise stress decreased steadily. In 2021, exercise stress was replaced by pharmacological stress as the most frequent stress modality. Camera systems showed a shift to more SPECT-CT systems. The use of gated SPECT increased to almost 90%. Quantitative scoring showed an increasing acceptance. The ratio of invasive coronary angiographies (ICA) to MPS was between 3.9 and 4.5. A significant proportion of ICA in the context of CCS (chronic coronary syndrome) was performed without prior testing for ischaemia.

CONCLUSION

The 2012 to 2021 MPS surveys reveal a continuously growing number of examinations with only a mild temporary effect of the COVID-19 pandemic and a centralisation with increasing numbers per centre. Performance and technical data reveal a high-grade adherence of MPS practice to the current ESC guideline. A large potential of non-invasive diagnostics remains for the future.

Optimal Protocol of Myocardial Perfusion Imaging for Reduction of Radiation Exposure

The Japanese Circulation Society (JCS) 2021 guideline on radiation safety in cardiology was updated based on the eight best practices for myocardial perfusion single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), which was determined by panels of international atomic energy agency (IAEA) nuclear cardiology protocols cross-sectional study (INCAPS). Although the guideline recommends to avoid too much ²⁰¹Tl or ²⁰¹Tl/^99mTc dual-isotope protocol, the utilization rate of ²⁰¹Tl for SPECT-MPI in Japan is considerably high compared to other countries. In Japan, protocols using ^99mTc should be appropriately promoted based on the guideline to reduce radiation exposure in SPECT-MPI. Among the eight practices, stress-only imaging is considered to be a useful strategy that contributes to a significant reduction in radiation exposure, and hybrid assessment in combination with rest computed tomography (CT)-MPI is one of the practical application methods.

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.

Moving into the next era of PET myocardial perfusion imaging: introduction of novel 18F-labeled tracers

The heart failure epidemic continues to rise with coronary artery disease as one of its main causes. Novel concepts for risk stratification to guide the referring cardiologist towards revascularization procedures are of significant value. Myocardial perfusion imaging using single-photon emission computed tomography (SPECT) agents has demonstrated high accuracy for the detection of clinically relevant stenoses. With positron emission tomography (PET) becoming more widely available, mainly due to its diagnostic performance in oncology, perfusion imaging with that modality is more practical than in the past and overcomes existing limitations of SPECT MPI. Advantages of PET include more reliable quantification of absolute myocardial blood flow, the routine use of computed tomography for attenuation correction, a higher spatiotemporal resolution and a higher count sensitivity. Current PET radiotracers such as rubidium-82 (half-life, 76 s), oxygen-15 water (2 min) or nitrogen-13 ammonia (10 min) are labeled with radionuclides with very short half-lives, necessitating that stress imaging is performed under pharmacological vasodilator stress instead of exercise testing. However, with the introduction of novel ¹⁸F-labeled MPI PET radiotracers (half-life, 110 min), the intrinsic advantages of PET can be combined with exercise testing. Additional advantages of those radiotracers include, but are not limited to: potentially improved cost-effectiveness due to the use of pre-existing delivery systems and superior imaging qualities, mainly due to the shortest positron range among available PET MPI probes. In the present review, widely used PET MPI radiotracers will be reviewed and potential novel ¹⁸F-labeled perfusion radiotracers will be discussed.

Current status of stress myocardial perfusion imaging pharmaceuticals and radiation exposure in Japan: Results from a nationwide survey

BACKGROUND

Ionizing radiation generated during medical imaging procedures is a matter of concern. However, the current status of radiopharmaceutical use in stress myocardial perfusion imaging (MPI) and the radiation exposure from these radiopharmaceuticals is unknown in Japan.

METHODS AND RESULTS

A nationwide survey was conducted from June through July 2016. The questionnaires on the radiopharmaceuticals used and their administered doses during stress MPI were sent to 641 nuclear medicine facilities. The responses were collected from 431 facilities and the effective dose (ED) for an adult with standard body weight was calculated. Forty-three percent of the facilities used only 201TlCl, 35% used only 99mTc radiopharmaceuticals, and the remaining 22% used both. The two main reasons for using 201TlCl instead of 99mTc radiopharmaceuticals were "more familiarity with the usage of 201TlCl than 99mTc radiopharmaceuticals" and "apprehension about increasing the burden of physicians performing tracer injection twice." The mean ED was 14.0 ± 5.5 mSv (range, 3.9 to 25.2 mSv), which was higher than that reported in other countries.

CONCLUSIONS

The ED of stress MPI radiopharmaceuticals in Japan is probably higher than the world standard because more than 50% of the facilities still use 201TlCl. We recommend revising the routine stress MPI protocol to reduce the effects of ionizing radiation.

[Nuclear Medicine in Germany. Updated key data and trends from official statistics]

AIM

Updated presentation of the spectrum of nuclear medicine in-vivo examinations and therapies from officially available statistics on out-patient and in-patient care as well as trends of structural data on nuclear medicine in Germany.

METHODS

Data from the German Federal Health Monitoring, from the frequency statistics of the statutory health insurance for out-patients and from the German Medical Association were used and supplemented by data from selective literature searches.

RESULTS

In descending order, thyroid, bone and cardiac scans continue to be the most frequent nuclear medicine procedures. With a marked increase of PET/CT and SPECT/CT, the number of basic scintigraphies is declining. Cardiac, lung and brain scans as well as lymph scintigraphies are increasingly requested, bone and thyroid scan decrease. The consultation of nuclear medicine physicians in private practices is increasing by 4 % per year (2009: 2 164 664; 2015: 2 687 359). The number of nuclear medicine physicians in the out-patient sector rose significantly (2009: 756, 2015: 939, growth 24 %) and has remained constant due to restrictions since 2013. The specialist recognitions of women in nuclear medicine increased (proportion currently 46 %). In hospitals, more PET(/CT) scanners (2009: 97; 2015: 125) and fewer gamma cameras (2009: 594; 2015: 550) are operated. The number of non-thyroid (and also out-patient) radionuclide therapies continued to increase.

CONCLUSION

With increased use of hybrid technologies, the nuclear medicine spectrum shows positive trends especially in nuclear cardiology and extra-thyroid therapy. These developments must be taken into account when amending regulations of specialist training and medical student teaching.