Key words interventional procedures - MR-imaging - CT - COVID-19 pandemic
Abbreviations and acronyms
IR:
interventional radiology
IRP:
interventional radiology procedure
IOP:
interventional oncology procedure
UCC:
University Cancer Center
Introduction
The ongoing COVID-19 pandemic has had an unprecedented impact on healthcare systems
worldwide. Due to government-imposed restrictions, public life in Germany almost came
to a standstill between March and April 2020 [1 ] and to a lesser degree during the second lockdown between January and May 2021 [2 ]
[3 ]. This, in combination with fear and uncertainty regarding coronavirus infection
among patients, led to a significant decrease in patients presenting for diagnostic
imaging and treatment [4 ]
[5 ]
[6 ]. Multiple studies have shown that there were fewer hospital presentations as well
as admissions of patients with, e. g., myocardial infarction and stroke, and also
of cancer patients [7 ]
[8 ]
[9 ]
[10 ]. A stage shift in cancer patients could be the consequence [11 ]
[12 ]
[13 ]
[14 ].
Interventional radiology (IR) plays an important role in the treatment of oncological
patients, especially in patients with hepatic tumors, but increasingly also in pulmonary
and renal lesions [15 ]
[16 ]
[17 ]
[18 ]
[19 ]. Interventional oncology as a therapeutic option for oncological patients is of
particular interest during times of added strain on resource-intensive areas like
surgery. Several studies have investigated the impact of the COVID-19 pandemic on
IR services. Studies from the US and UK [20 ]
[21 ] found a significant decrease in the number of interventional radiology procedures
(IRPs), including interventional oncology procedures (IOPs), whereas a Singaporean
study found no significant difference in comparison to previous years [22 ]. A study by Zattra et al. investigated the impact of the COVID-19 pandemic on cancer
imaging in the US and concluded that cancer imaging was severely impacted [23 ].
The aim of our study was to assess the influence of the COVID-19 pandemic and subsequent
lockdown measures on the number of therapeutic IOPs and diagnostic imaging studies
at a German university hospital with high volumes of IRPs.
Patients and Methods
The number of diagnostic CT and MRI examinations and therapeutic IOPs that were performed
at our institution was analyzed retrospectively. Therapeutic IOPs performed at our
institution include transarterial chemoembolization of hepatic tumors as well as radiofrequency
and microwave ablation of hepatic, pulmonary, and renal tumors. Non-therapeutic IOPs
like biopsies were not included. The number of therapeutic IOPs as well as diagnostic
inpatient and outpatient CT and MRI examinations was extracted per month from the
radiology information system (ORBIS, Dedalus HealthCare, Germany) for the years 2010
to 2021. In a subgroup analysis, the number of CT and MRI examinations performed on
request by our University Cancer Center (UCC) was reviewed. The overall number of
oncological imaging examinations is difficult to determine due to multiple requesting
departments, incorrect wording on requests, etc. Therefore, we chose referrals by
the UCC as a surrogate marker for oncological imaging.
Forecasting models were built using SPSS (IBM Corp. Released 2022. IBM SPSS Statistics
for Windows, Version 29.0., USA). We used monthly data from January 2010 to December
2019 to predict expected monthly data from January 2020 to December 2021 with a 95 %
confidence interval. The real numbers of procedures from January 2020 to December
2021 were compared with the predicted numbers to calculate residual differences, which
were considered statistically significant if the real number was outside of the 95 %
confidence interval of the forecasting model’s prediction (p < 0.05).
Institutional Review Board approval was obtained. Written informed consent was waived
by the Institutional Review Board. All performed procedures were part of routine clinical
care.
Diagrams and tables were created using Microsoft Office Excel 2019 (Microsoft Corporation,
USA).
Results
All results are summarized in [Fig. 1 ].
Fig. 1 Monthly real and predicted numbers with upper and lower confidence limits in 2020
and 2021 (UCC: University Cancer Center).
CT
During the first German lockdown (March/April 2020), outpatient CT examinations showed
a significant decrease, which was most pronounced in April 2020. For the remaining
year, the number of CT examinations recovered partially but remained below the predicted
numbers. During the second lockdown (January to May 2021), the number of examinations
did not drop significantly but remained below the predicted numbers.
The number of inpatient CT examinations was also below the predicted numbers in early
2020, with a significant decrease in May immediately after the first lockdown. During
the following months, the number of inpatient CT scans stayed close to the predicted
numbers, while the number significantly exceeded the predicted number shortly prior
to the second lockdown and remained higher than predicted during the lockdown.
The number of CT examinations performed after referrals from the UCC stayed around
the predicted number during both lockdowns and did not show a significant decrease.
MRI
During the first German lockdown (March/April 2020), the number of outpatient MRI
examinations was below the predicted numbers, with a significant drop in March. In
the months after the lockdown, the number of examinations was higher than predicted
and during the remaining year stayed close to the predicted level. During the second
lockdown (January to May 2021), the number dropped minimally below the predicted level
in January, while it exceeded the predicted levels from February to May and even showed
a significant increase in March 2021.
The number of inpatient MRI examinations stayed close to the predicted levels during
the first lockdown. During the second lockdown, there was a sharp, but not quite significant
decrease in January 2021, but the number of examinations recovered by March.
The number of MRI examinations performed after referrals from the UCC decreased significantly
at the beginning of the first lockdown in March 2020 and recovered in April up to
the predicted number. During the second lockdown, the number of examinations was always
below the predicted levels, with significant drops in all months except March 2021.
IOPs
The number of therapeutic IOPs did not show a significant decrease during both lockdowns
but moved around predicted levels, with a tendency to higher than predicted numbers
in 2021. Immediately prior to both lockdowns (February 2020/December 2020), the number
of procedures exceeded the upper confidence limit.
Discussion
The COVID-19 pandemic has had a tremendous influence on health care systems worldwide.
Our study shows that the number of outpatient diagnostic CT and MRI examinations decreased
significantly during the first lockdown, while the second lockdown had overall less
of an effect. Regarding patients referred by the University Cancer Center, the number
of CT examinations showed no significant decrease, while the number of MRI examinations
dropped significantly during both lockdowns. The number of therapeutic IOPs on the
other hand was not affected, showing no decrease during both lockdowns.
We found a more pronounced decrease in the overall number of outpatient CT examinations
compared to outpatient MRI examinations, which could be due to a different case composition
in MR and CT imaging at our institution and a lower number of patients presenting
for, e. g., trauma-related CT scans during the lockdowns. The number of inpatient
CT and MRI examinations did not show a significant decrease during the lockdowns,
which might be caused by a shift from outpatient to inpatient imaging and a marked
increase in thoracic CT examinations in COVID-19-patients. The smaller effect of the
second lockdown in 2021 compared to the first lockdown in 2020 could be due to newly
established standardized protocols and adapted patient and hospital staff behavior
[24 ]
[25 ]
[26 ].
Several studies have assessed the effect of the COVID-19 pandemic on IR services.
Two studies found a marked decrease of IRPs in the UK and US in March and April 2020,
compared to the same time period in 2019. The study by Cahalane et al. showed a 46 %
reduction in the number of IRPs, with a 17 % decrease (35 versus 29) in IOPs [20 ]. The IOPs in this study included inter alia ports, catheters, and tumor biopsies,
which reduces comparability to our study. Nevertheless, it also demonstrated a less
pronounced reduction in the number of IOPs.
A multicenter study including data from six NHS trusts and health boards in the UK
by Zhong et al. found a 31 % decrease in the overall IR caseload, with a 91.7 % (24
cases in March/April 2019 compared to 2 in March/April 2020) reduction in the number
of image-guided ablation procedures [21 ]. The number of abdominal embolization procedures dropped by 57.4 % (108 versus 46),
but the article does not elaborate on which procedures were included in this number. Different
national or local approaches to COVID-19-associated restrictions of hospital resources
or differences in patient behavior are possible explanations.
A study from Singapore showed similar results to our study, with only a 5.1 % decrease
in the total number of IRPs within the first half of 2020 compared to the same time
period in 2019 and a similar distribution of the weekly number of IRPs [22 ]. IOPs made up 13 % of IRPs in 2019 and 12.1 % in 2020. The overall lower decrease
in IRPs in comparison to the abovementioned studies could be due to better preparation
in Singapore with regards to pandemic protocols and measures after having gone through
the SARS-CoV outbreak in 2003 and the H1N1 pandemic in 2009 [27 ]
[28 ].
Elective cancer surgery significantly decreased due to the COVID-19 outbreak, particularly
during the lockdowns [13 ]. This development was likely multifactorial, with fewer patient presentations and
admissions, staff shortages, and reduced operating room availability playing a role
[9 ]
[10 ]
[11 ]
[12 ]
[13 ]
[14 ]. At our hospital, around 30 % of non-emergency surgical procedures were postponed
and up to six operating rooms were closed. The reduced offer of surgical services
might have caused a shift to therapeutic IOPs, which require fewer resources and allow
for shorter hospital stays [29 ]
[30 ].
Few studies have investigated the effect of the COVID-19 pandemic on diagnostic imaging
studies. Zattra et al. analyzed trends in oncological CT imaging between January and
November 2020 and concluded that cancer imaging was severely impacted, with the number
of outpatient screenings and initial workups in particular not recovering to pre-COVID
levels [23 ]. They also observed an increase in inpatient and emergency department CT examinations
from March 2020 on. This is in keeping with our findings of reduced overall outpatient
CT and MR imaging during the first German lockdown and a shift towards inpatient CT
imaging immediately after the first lockdown and during the second lockdown.
In our study, the number of MRI examinations requested by the UCC decreased significantly
during both lockdowns. In contrast, we could not demonstrate a decrease in the number
of CT examinations on referral by the UCC, which could be due to a shift of patients
from MR towards CT imaging, since resources are generally more limited in MRI and
examinations are much more time-consuming. Another possible explanation is our use
of referrals by the UCC as a surrogate marker for oncological imaging, which does
not include all oncological imaging performed.
The use of the abovementioned surrogate marker for oncological imaging is a limitation
of this study, as well as the relatively low monthly number of therapeutic IOPs and
the considerable variability of the number of procedures performed each month, which
impedes assessment of the influence of external factors.
In conclusion, our single-center study shows less influence of lockdown measures on
the number of therapeutic IOPs, compared to the number of overall diagnostic outpatient
CT and MRI examinations. Oncological MRI examinations were affected most severely
during the lockdowns. To avoid adverse patient outcomes, adequate protocols and pathways
for diagnostic imaging during possible future pandemic outbreaks should be implemented.
Clinical Relevance
The COVID-19 pandemic has put an unprecedented strain on healthcare systems worldwide.
To guarantee high-quality, timely patient care, data regarding the influence of the
pandemic and consecutive government measures is vital. Interventional oncology procedures
are resource-sparing and in this study no significant negative influence on the number
of procedures during the lockdowns was shown. In contrast, the number of outpatient
CT and MRI examinations was in part affected severely. Therefore, adequate triage
protocols and pathways for future pandemic outbreaks are essential.
