Key words cardiovascular imaging - ESCR Registry - survey - quality assessment - certification
program
Introduction
Over the last decade, cross-sectional cardiovascular imaging, i. e., computed tomography
(CT) and magnetic resonance imaging (MRI), have transitioned from an up-and-coming
field to modalities deeply rooted in clinical practice.
The growing body of evidence in the pertinent literature has emphasized cross-sectional
cardiovascular imaging (CVI) in a plethora of national and international guidelines
[1 ]
[2 ]
[3 ], which resulted in the consolidation of existing indications as well as the definition
of new ones. Particularly in coronary artery disease, CT and MRI are noninvasive,
low-risk alternatives that partly replace cardiac catheterization, providing new parameters
and differential diagnoses that are otherwise not available [4 ]
[5 ]. This has also led to a broad echo in the national radiological community [6 ]
[7 ]. Against this background, a substantial increase in the demand for CVI imaging is
expected [8 ].
Within the German Roentgen Society (Deutsche Röntgengesellschaft e. V., DRG), CVI
is anchored with the Cardiovascular Imaging working group (WG CVI; AG Herz- und Gefäßdiagnostik).
The DRG aims to certify radiologists with special expertise in performing and interpreting
CVI studies. For this purpose, a certification program for individuals and institutions
as well as a training program accessible for German-speaking radiologists has been
established [9 ]. Moreover, a registry for cardiovascular CT and MRI examinations has been maintained
through international cooperation with the European Society of Cardiovascular Radiology
(ESCR) since 2012 for documentation and accreditation purposes, to identify centers
for initiation of multicenter trials, to substantiate examination figures, ensure
the highest quality of patient care, and to promote CVI expertise beyond national
borders.
The aim of this study was to assess the national availability of high-quality, certified
cardiovascular imaging in Germany as well as the characteristics of the radiological
infrastructure and clinical routines: Firstly, by analyzing the DRG database for certified
centers and individuals, secondly, by conducting a nation-wide online survey among
radiology institutes, and thirdly, by extracting data from the ESCR registry.
Methods
Data acquisition of certified centers and personnel
The number of certified centers, CVI-certified radiologists, and members of the WG
CVI was extracted from the DRG database for each year from January 1, 2015 until February
1, 2021. Institutions were assigned to a region in Germany based on the first two
digits of their respective postcode. The number of postcode regions with access to
a certified center was documented. Individuals' certification levels are graded with
increasing expertise from Q1 (basic knowledge) to Q3 (comprehensive knowledge, instructor).
Each Q-level can be acquired for CT and MRI separately. A detailed description of
the requirements for each level can be found elsewhere [9 ].
Development of the questionnaire and distribution
Members of the WG CVI and the DRG developed the survey. The questionnaire was published
online twice, between August 24 and October 31, 2020 and between January 11 and February
1, 2021, employing a software designed to conduct online surveys (SurveyMonkey, SurveyMonkey
Europe Sarl, Luxembourg).
To assure generalizability, the survey participants were recruited via the email distributor
of the Conference of Chairs of University Hospital Radiology (Konferenz der Lehrstuhlinhaber,
KLR), the Chief Physician Forum of the DRG (CAFRAD), and via the email distributor
of the Heads of Institutions of the Professional Association of German Radiologists
(Berufsverband der Deutschen Radiologen e. V., BDR). German university hospitals and
certified centers were once reminded by telephone to participate in the survey. An
independent central office received all answers to the survey. Participants were encouraged
to provide their institution's name with assurances of confidentiality and strict
adherence to data protection guidelines. For responses, which did not provide the
name of the institution, duplicates were excluded by matching the given answers' IP
addresses and redundancies. Due to the nature of the survey, ethics committee approval
was not necessary.
Structure of the questionnaire
The questionnaire included 18 questions in total, referring to the following items.
All data were related to the year 2019.
Characterization of the institutions and certified personnel
The first two questions addressed the location of the institution and its structure.
Participants were asked to name their institution and specify their location with
a postal code in a free text box. Possible answers regarding the institutional type
were i) university hospital, ii) non-university hospital, iii) private practice.
The following nine questions asked for the number of Q1- to Q3-certified radiology
specialists in the department. The number of CVI-certified staff was requested for
CT, MRI, and combined for CT and MRI, respectively.
Number of examinations and reporting standards
Two questions referred to the number of cardiovascular CT and MRI examinations per
institution. Here, planning examinations for TAVI and PVI interventions were explicitly
included. The next two questions addressed the reporting situation of cardiovascular
CT and MRI in the respective department. For both modalities, the respondents could
choose between reporting performed solely by radiologists, joint reporting by radiologists
and non-radiologists, and reporting by non-radiologists alone.
Next, participants were asked whether examinations are submitted to the international
MRCT ESCR registry (14) for the documentation of radiological cross-sectional examinations.
In case of a positive answer, the proportion of examinations entered in the registry
could be indicated. The categorical answer options, i) 1–25 %, ii) 26–50 %, iii) 51–75 %
and iv) 76–100 %, were available.
Communication with the DRG and the WG CVI
Finally, the respondents were asked about possible topics on which the DRG and the
WG CVI should provide information as a matter of priority. The following options were
given: i) cooperation with colleagues, ii) certification, iii) technology, and iv) medical
education and training.
Data from the ESCR Registry
The number of institutions in Germany entering examinations in the ESCR registry was
determined from the registry's database. The data on the reporting habits of cardiac
CT and cardiac MRI examinations were extracted from the registry. Possible categories
were i) reporting by a radiologist, ii) consensus reading (radiologist & cardiologist),
iii) reporting by a cardiologist, iv) separate reading, or v) other.
Statistics
Statistical analyses were performed using SPSS (v25.0, IBM Corp., United States).
Descriptive statistics with respective percentages were used. If applicable, the median
with [25 %; 75 % range] was given. Non-parametric data were analyzed using the Mann-Whitney
U test for two groups. To minimize error due to multiple testing, the Kruskal-Wallis
test was employed when more than two groups were present. A P-value of < 0.05 was
considered statistically significant.
Results
Locoregional distribution of certified centers and personnel
In total, 71 centers in Germany and 1278 persons were certified by the DRG, and the
WG CVI had 1612 registered members on February 1, 2021. Of the certified radiologists,
902 individuals were certified as Q1 (71 %), 227 as Q2 (18 %) and 149 as Q3 (12 %).
The data of the previous years with illustration of the corresponding growth can be
found in [Fig. 1 ]. Of the 99 postcode regions in Germany, a total of 56 (57 %) had direct access to
a certified center. Two centers were located in nine of these regions, and three centers
in four regions. A corresponding overview of the regional distribution of certified
centers with capture areas can be found in [Fig. 2 ].
Fig. 1 Number of certified centers in Germany, certified individuals (combined Q1–3, with
increasing expertise) and members of the Cardiovascular Imaging Working Group (WG
CVI) from 2015 to 2021. The growth figures in percent refer to the period from 2015
to 2021 for each subgroup.Abb. 1 Anzahl der zertifizierten Zentren in Deutschland, der zertifizierten Personen (kombiniert
Q1–3, mit steigender Expertise) und der Mitglieder der Arbeitsgruppe Herz- und Gefäßbildgebung
von 2015–2021. Die Wachstumszahlen in Prozent beziehen sich auf den Zeitraum von 2015–2021
für jede Untergruppe.
Fig. 2 Overview of the centers certified for cardiovascular imaging (red crosses) in Germany
in January 2021 and their corresponding catchment areas with a driving time of 30/45/60
minutes (dark blue/light blue/turquoise). Triangles represent CT Q2, and Q3 certified
radiologists, circles MRI Q2, and Q3 certified radiologists. (Calculation of isochrones
using openrouteservice, © openrouteservice.org by HeiGIT | Map data © OpenStreetMap
contributors).Abb. 2 Übersicht über die für kardiovaskuläre Bildgebung zertifizierten Zentren (rote Kreuze)
in Deutschland im Januar 2021 und ihre entsprechenden Einzugsgebiete in 30/45/60 Minuten
Fahrzeit (dunkelblau/hellblau/türkis). Dreiecke stellen CT-Q2- und -Q3-zertifizierte
Radiologen dar, Kreise MRT-Q2- und -Q3-zertifizierte Radiologen. (Berechnung der Isochronen
mittels openrouteservice, © openrouteservice.org by HeiGIT | Map data © OpenStreetMap
contributors).
Evaluation of the Questionnaire
Characterization of the institutions and certified personnel
A total of 184 responses were received, of which 30 were from university hospitals,
76 from non-university hospitals and 78 from private practices. Answers were received
from 72 (73 %) of the 99 German postcode regions.
In total, the survey captured 695 certified professionals, representing 71 % of the
total number of registered individuals with certification in 2019. These were divided
into 427 Q1 (61 % of the surveyed population; 249 CT&MRI, 90 CT only, 88 MRI only),
173 Q2 (25 %; 107 CT&MRI, 38 CT only, 28 MRI only) and 95 Q3 certified individuals
(14 %; 77 CT&MRI, 9 CT only, 9 MRI only). Of those included in the survey, 262 individuals
(38 %) worked at university hospitals, 289 (42 %) at non-university hospitals, and
144 (21 %) at private practices (P < 0.01). An illustration of the data can be found
in [Fig. 3 ].
Fig. 3 Overview of the number of all Q-certified radiologists covered by the survey. The
total number and the subdivision into the different Q-levels (Q1–3, ascending expertise)
and their distribution among the different types of institutions are shown. The percentages
refer to the proportion of radiologists with the corresponding Q-certification in
the total of each individual Q-level. The number of certified staff working at the
different institutions was significantly different (*).Abb. 3 Übersicht über die Anzahl aller in der Umfrage erfassten Q-zertifizierten Radiologen.
Dargestellt sind die Gesamtzahl und die Unterteilung in die verschiedenen Q-Stufen
(Q1–3, aufsteigende Expertise) sowie deren Verteilung auf die verschiedenen Einrichtungstypen.
Die Prozentangaben beziehen sich auf den Anteil der Radiologen mit der entsprechenden
Q-Zertifizierung an der Gesamtzahl jeder einzelnen Q-Stufe. Die Anzahl der zertifizierten
Radiologen, die in den verschiedenen Einrichtungen arbeiten, war signifikant unterschiedlich
(*).
Number of examinations and reporting standards
A total of 69,286 CT and 64,281 MRI examinations were performed in the participating
institutions in 2019. Of the CT examinations, 30,682 (44 %) were performed at university
hospitals, 27,521 (40 %) at non-university hospitals, and 11,083 (16 %) at private
practices. Of the MRI examinations, 22,630 (33 %) were performed at university hospitals,
28,151 (40 %) at non-university hospitals, and 13,500 (20 %) at private practices.
The median number of examination was 610 [459, 1400] CT examinations and 525 [303, 911]
MRI examinations performed at university hospitals, 213.5 [103.3; 471.3] CT examinations
and 200 [99, 412] MRI examinations at non-university hospitals, and 50 [0, 191] CT
examinations and 23 [0, 149] MRI examinations at private practices in 2019. The data
is illustrated in [Fig. 4 ].
Fig. 4 Summary of a cardiac CT and b MRI examinations performed at the participating institutions, in total and per institution
type. The percentages refer to the proportion of examinations out of the total number
per modality. The number of examinations for both modalities was significantly different
(*) between all institutions. Below, the median for exams performed for each modality
at each institution is given.Abb. 4 Zusammenfassung der a kardialen CT- und b MRT-Untersuchungen, die in den teilnehmenden Einrichtungen durchgeführt wurden, insgesamt
und pro Einrichtungstyp. Die Prozentangaben beziehen sich auf den Anteil der Untersuchungen
an der Gesamtzahl pro Modalität. Die Anzahl der Untersuchungen für beide Modalitäten
war zwischen allen Einrichtungen signifikant unterschiedlich (*). Im unteren Abschnitt
der Abbildung ist der Median der durchgeführten Untersuchungen für jede Modalität
in jeder Einrichtung angegeben.
In most institutions, reporting is either done solely by the radiologist or collaboratively
with non-radiologists. CT examinations/MRI examinations were reported by the radiologist
alone in 106/85 institutions (74/59 %), in cooperation with non-radiologists (usually
the referring physicians) in 37/52 institutions (26/36 %), and exclusively by non-radiologists
in 1/7 institutions (1/5 %). This question was not answered by 40 institutions. A
detailed description of reporting habits per modality/institution, and a comprehensive
visualization of the data in this paragraph is provided in [Fig. 5 ].
Fig. 5 Overview of the reporting habits for a cardiac CT and b MRI in the surveyed institutions. Except for MRI reporting habits between non-university
hospitals and private practices, there were no significant differences (*).Abb. 5 Übersicht über die Befundungsgewohnheiten für a kardiale CT und b MRT in den befragten Einrichtungen. Mit Ausnahme der MRT-Befundungsgewohnheiten zwischen
den nichtuniversitären Krankenhäusern und den niedergelassenen Ärzten gab es keine
signifikanten Unterschiede (*).
Participation in the ESCR registry
Overall, 88 institutions (48 %) documented their examinations in the ESCR registry.
38 institutions (40 %) indexed 1–25 % of all their cardiac exams in the registry,
each of 10 institutions (11 %) reported 26–50 % and 51–75 %, and 37 institutions (39 %)
76–100 %. In proportion, 77 % of university hospitals, 59 % of non-university hospitals
and 27 % of private practices participated in the ESCR registry. A further, more detailed
description of the data is presented in [Fig. 6 ].
Fig. 6 Percentage of the surveyed institutions participating in the ESCR registry, in total
and per institution type, and proportion of examinations entered in the ESCR registry
at the various institutions.Abb. 6 Prozentualer Anteil der befragten Einrichtungen, die am ESCR-Register teilnehmen,
insgesamt und pro Einrichtungstyp, und Anteil der im ESCR-Register erfassten Untersuchungen
an den verschiedenen Einrichtungen.
Communication with the DRG and the WG CVI
The proposed topics were prioritized by the survey participants as follows: cooperation
with colleagues (n = 34, 43 %), certification (n = 48, 61 %), technology (n = 27,
34 %), medical education and training (n = 50, 63 %). This question was skipped by
106 participants.
Data from the ECSR Registry
According to data from the ESCR registry, 181 German sites reported cardiac MR and
160 German sites also reported cardiac CT cases to the registry (14, 17), indicating
that not all radiological sites performing cardiac CT und MRI in Germany and documenting
their cases in the ESCR registry responded to the survey. The data concerning the
reporting habits according to the registry can be found in [Fig. 7 ].
Fig. 7 Frequency of consensus versus single reading by radiologists and cardiologists of
cardiac CT and MR examinations according to the ESCR Registry (modified from [10 ]).Abb. 7 Häufigkeit von Konsens- gegenüber Einzelbefundung durch Radiologen und Kardiologen
bei kardialen CT- und MR-Untersuchungen nach dem ESCR-Register (modifiziert aus [10 ]).
Discussion
In the present analysis, we describe the national availability and structural and
interdisciplinary features of high-quality, certified cardiovascular imaging by radiological
institutions across Germany. Our survey's key result is that there is nationwide availability
of high-quality CVI in Germany by radiology specialists. Two facts mainly demonstrate
this: Firstly, both certified centers and professionals provide specialized service
with good accessibility within almost all regional clusters. Secondly, there is a
high number of radiologists specialized and certified in CVI across all institutional
types, with a continuing strong increasing development.
The special expertise has been promoted by a structured education program of the DRG
as the basis for the certification of centers. The educational courses are taught
at regular workshops and congresses (e. g., annual Congress of the ESCR, German Cardiodiagnostic
Days (Deutsche Kardiodiagnostiktage – DKDT: https://www.kardiodiagnostik.de ) and German Roentgen Congress), and by means of a comprehensive online program, both
nationally and internationally. Also, the fully digitalized learning platform CONRAD (DICOM-data
based), which includes a realistic, cardiovascular case-reading environment, has made
it possible to provide educational content and continuation of the certification processes
during the global COVID 19 pandemic restrictions. The steadily increasing number of
certified centers and individuals as illustrated in [Fig. 1 ] is also a strong indicator of an effective and successful subspecialization process.
Although a large number of examinations was performed regardless of the institution's
structural character, there was a slight imbalance in favor of the university hospitals.
However, the majority (56 %) of cardiac CT and MRI examinations in 2019 were performed
at nonacademic institutions. This observation may be attributable to the following
facts: i) As with all new and/or specialized medical developments, cardiac CT and
MRI were usually introduced and evaluated at university hospitals first to demonstrate
the clinical robustness and utility before widespread implementation took place. For
cardiac CT and MRI, the transition from restricted local expertise to widely available
expertise has successfully been accomplished, as demonstrated by data from the ESCR
registry with growing numbers of non-university hospitals and medical practices. According
to recent publications based on data of the ESCR registry, about 36 % of cardiac MRI
examinations in Europe were performed at academic and 64 % at non-academic radiological
centers [10 ]
[11 ]
[12 ].
Currently, there are 35 certified non-university centers and 36 certified university
hospitals registered in Germany. Although the radiological community with its natural
affinity for innovative imaging technologies has implemented a widespread service
of high-quality CVI, a substantial impediment to increasing the number of examinations
in private practice may be the limited reimbursement by the statutory health insurance
funds. With regard to the high level of evidence for both cardiac CT and MRI illustrated
by recently updated guidelines [1 ]
[2 ]
[3 ], full coverage of both modalities by statutory health insurance may be desirable.
Notably, the number of sites performing and submitting cardiac CT examinations to
the ESCR registry in Germany increased from an already high number of 130 in 2018
to 160 in 2020 [13 ], emphasizing that radiological institutions are determined to provide the best possible
medical care despite the limited reimbursement situation. CT and MRI of the cardiovascular
system are still among the most technologically demanding applications of these modalities.
Profound knowledge of the organ's pathophysiology and a high level of expertise in
using the technology is required to ensure a high standard of patient care and clinical
safety [14 ]. To guarantee this, the DRG offers a dedicated education curriculum with certification
for technical staff [15 ]. CVI has not only been validated in detail by national and international radiological
institutes but is also continually being further developed there. In terms of MRI,
techniques such as T1 and T2 mapping are in the process of leaping from scientific
application to clinical routine [16 ]
[17 ], and new imaging acceleration techniques such as compressed sensing are showing
their strengths in imaging a moving organ [18 ]. Considering CT, techniques such as myocardial CT perfusion and CT-derived fractional
flow reserve promise to provide insight beyond simple anatomy imaging [19 ]
[20 ]. Here radiology has demonstrated its high innovation power regarding clinical and
technical aspects, embracing new technology (e. g., artificial intelligence) whenever
that benefits the patient.
It can be anticipated that radiology, as a bridging discipline with a high affinity
for the technological and the medical field, can achieve its highest and most substantial
contribution to medicine by combining broad clinical-medical knowledge with technical
expertise. This expertise is the fundamental foundation to indicate and select the
appropriate imaging technique and guarantees targeted, comprehensive diagnostics and
therapeutics for each patient. Furthermore, an individual risk-benefit assessment
in terms of radiation exposure is essential given the predicted increase in the use
of advanced imaging techniques in clinical practice [8 ]. Against the background of demographic development and rising costs, it seems mandatory
to maintain the four eyes principle (“Vier-Augen-Prinzip”) with inclusion of a referring
physician, e. g., a cardiologist, and a physician performing the diagnosis, i. e.,
the radiologist, in order to assure economic sustainability and efficiency in the
German health care system [21 ]. For example, in a recently published randomized controlled trial of patients with
an unclear NSTEMI diagnosis, initial cardiac MRI and coronary CTA provided non-coronary
differential diagnoses, reduced the number of cardiac catheterizations, and led to
a more appropriate referral to invasive procedures [22 ]. A meta-analysis demonstrated that coronary CTA was associated with a shorter length
of stay in the emergency department and lower costs [23 ].
Our observation is that in most centers certified radiologists without direct interaction
with non-radiology disciplines perform reporting of CVI exams, although there is a
trend towards joint reporting in non-university hospitals, and for MRI compared to
CT. It needs to be emphasized that especially the complex field of CVI clearly benefits
from a regular exchange with disciplines outside of radiology to guarantee the highest
possible medical quality. These observations are in line with the position statements
of professional societies [24 ] and clinical reality as documented in the ESCR registry [12 ], in which consensus reading is practiced by approximately 20 % of users in CT and
approximately 30 % in MRI ([Fig. 7 ]). However, it cannot be ruled out that there are shadow reports of individual disciplines
that are not consistent with the radiological report in certain aspects, creating
uncertainties in patient treatment and medicolegal perspectives. There is no doubt
that the interaction with colleagues from cardiology, pediatric cardiology, and cardiovascular
surgery results in modification of clinical relevance and prioritizing, thereby benefiting
the individual patient. This important interaction is practiced on a clinical level
in joint interdisciplinary daily pre-TAVI meetings in the so-called Heart Team [25 ], joint consensus recommendations for cardiovascular imaging [26 ], and specialized congresses such as the “German Cardiodiagnostic Days”. Another
challenge is that CVI imaging is not restricted to a single organ or structure (e. g.,
coronary arteries) but also adjacent organs such as the lungs, breasts, and lymph
nodes. For example, in a relevant number of cases with suspected NSTEMI, a different
acute diagnosis was made on cardiac MRI [22 ], and in up to 44 % of cases, incidental findings with potential clinical relevance
were present in CVI [27 ]. Radiology has the broad medical expertise to correctly interpret these extracardiac
findings. Furthermore, there is a strong need to establish processes that will handle
the increasing demand for CVI and follow-up imaging that focused clinical disciplines
cannot manage [28 ].
Given the high relevance of interaction with various disciplines, including the central
role of general practitioners within the German healthcare system, structured reporting
is a tool with great potential to further improve interdisciplinary communication
[29 ]. The WG CVI has already published templates for various cardiovascular pathologies
and made them publicly available via an open-source license [30 ] and further implementation in clinical radiology service is highly recommended.
Limitations
The following limitations must be considered when evaluating this data collection:
This survey does not cover all radiological institutions and is therefore only representative
to a certain extent. For all non-certified or anonymous participants, a selection
bias cannot be excluded, as an affinity for or particular interest in cardiac imaging
could have influenced the willingness to participate. Furthermore, there is a relative
predominance in favor of the university hospitals, which are included almost in their
entirety, compared to the non-university hospitals and practices/clinics that were
not all surveyed.
Conclusion
This comprehensive analysis provides a detailed picture of the development and current
status of radiological cardiovascular imaging in Germany in particular and in a European
context, demonstrating that high-quality advanced cardiovascular imaging service by
radiologists is available nationwide. Although a substantial number of non-university
hospital and private practice-based radiologists perform cardiac CT and MRI, even
wider availability may be hampered by insufficient reimbursement by statutory health
insurance. A continued specialized education and certification system, a comprehensive
radiology risk-benefit analysis, including assessment of radiation exposure and incidental
findings, and increased interaction with relevant focused disciplines outside radiology
is essential to accommodate the predicted substantial need for advanced cardiovascular
imaging in the future and in the era of personalized medicine.
“High-quality advanced cross-sectional cardiovascular imaging service by radiologists
is available and accessible nationwide in Germany.”
“Highly qualified specialist knowledge in cardiovascular imaging is widely represented
in university hospitals, non-university hospitals, and private practices.”
“The national certification programs successfully contribute to the dissemination
and deepening of advanced cardiovascular imaging expertise with a growing number of
certified professionals and centers.”
“The ESCR registry is an established international tool for the documentation of cardiovascular
imaging data.”
