Patients
This retrospective study was approved by our Institutional Review Board with a waiver of informed consent. For this type of study formal consent is not required. For ACT utilization analysis, we retrospectively reviewed all patients who underwent procedures in one of three integrated ACT suites from January 2017 to December 2017. We also looked at procedure time and room occupation time of procedures performed at our institution from January 2016 to September 2019, for comparison between standard angiography rooms and ACT rooms.
ACT Interventional Radiology Suite
We analyzed the procedures performed in 3 different integrated ACT rooms. Two of them were equipped with an Innova 4100 angiography unit combined with a LightSpeed CT (ACT/SmartGantry Option LS system, GE Healthcare), and one was equipped with an IGS 540 combined with a Discovery RT wide bore CT (INTERACT Discovery RT, GE Healthcare). The angiography table was shared with the CT unit, which was mounted on a rolling platform, and as opposed to in conventional CT systems, the gantry was moving instead of the table during a CT scan. The ACT system had a user interface that allowed users to quickly switch the system into either imaging modality mode, and each system was equipped with a dedicated CT fluoroscopy kit.
In order to maximize patient access and scan range, the table was usually fully extended during CT scans, and more specifically during CT-guided procedures, though there was no specific requirement regarding the table’s longitudinal position to perform a CT acquisition. The ACT system allowed users to acquire multiple CT scans using a single scout image even if the user had changed the active modality from CT to fluoroscopy during the case.
Ultrasound devices used during the procedures were both the Logiq E9 or Logic S7 (GE Healthcare) systems.
ACT suite usage analysis
The term “procedure” was considered to be the occurrence of a patient entering the ACT suite. Each procedure could have 1, 2, or more interventions done on the patient with each intervention done under guidance of either imaging modality.
The procedures were divided into 3 categories based on the imaging modality used during each intervention:
(1) Standard, in which the patient underwent a single procedure using either fluoroscopy, CT or Ultrasound (US)
(2) Combined, in which the patient underwent a single procedure utilizing both fluoroscopy and CT
(3) Staged, in which the patient underwent two separate but successive procedures using fluoroscopy and CT individually (Table 1).
Table 1
Procedures classification
1st /2nd intervention
|
none
|
CT
|
XA
|
US
|
CT + XA
|
CT
|
Standard
|
Standard
|
Staged
|
Standard
|
Staged + Combined
|
XA
|
Standard
|
Staged
|
Standard
|
Standard
|
Staged + Combined
|
US
|
Standard
|
Standard
|
Standard
|
Standard
|
Combined
|
CT + XA
|
Combined
|
Staged + Combined
|
Stage + Combined
|
Combined
|
Staged + Combined
|
Procedure categories based on the imaging modality combinations of the 1st intervention (1st column) and the 2nd one (1st row). If more than 2 interventions were performed, the same logic was applied. All procedures were classified regardless the use of ultrasound in addition to the other modalities as it’s common practice in interventional radiology and not relevant for the current study.
If a procedure had one intervention utilizing only one modality (CT or fluoroscopy) and a second intervention utilizing both, the procedure would be categorized as both a Combined and Staged procedure. Procedures where US was used in combination with either CT or Fluoroscopy were referred to as simple procedures since they are common practice in the standard IR suite and not relevant for the current study. The importance of Combined and Staged procedures in the ACT suites procedure mix was evaluated by comparing the procedure types occurrences and room occupation time.
For each procedure performed in ACT suites between January 2017 and December 2017, the following data relevant for the procedure was obtained: procedure description, date, type, room occupation time, body part treated, and imaging modalities used during the procedure (CT, Fluoroscopy, US).
The most frequently performed Combined procedures were reviewed to determine how each modality was used and in which purpose.
Most common staged ACT procedure versus equivalent single modality room procedures comparison
In a second retrospective analysis, the procedure type, duration and the room occupation time were surveyed for all Standard and Staged procedures performed in the ACT suites between January 2016 and September 2019. The most common Staged procedure performed in ACT suite was compared to the 2 equivalent single procedures in terms of procedure duration and room occupation time. Due to the type of data available, only the Staged procedures where the gold standard in interventional oncology practice is the use of angiography for one intervention and CT for the other intervention were selected.
Statistical Analysis
Usage of the different imaging modalities was evaluated using standard analytic tools, both in terms of use per procedure and time spent using each modality.
The room occupation time of staged procedures was compared to the cumulative room occupation time averages of equivalent single procedures using a one sample t-test. The comparison of procedure durations was evaluated in the same way.