Cost of Low-Value Imaging Worldwide: A Systematic Review

Abstract

Background and Objective

Imaging with low or no benefit for the patient undermines the quality of care and amounts to vast opportunity costs. More than 3.6 billion imaging examinations are performed annually, and about 20–50% of these are of low value. This study aimed to synthesize knowledge of the costs of low-value imaging worldwide.

Methods

This systematic review was based on the PRISMA statement. The database search was developed in Medline and further adapted to Embase-Ovid, Cochrane Library, and Scopus. Primary empirical studies assessing the costs of low-value diagnostic imaging were included if published between 2012 and March 2022. Studies designed as randomized controlled trials, non-randomized trials, cohort studies, cross-sectional studies, descriptive studies, cost analysis, cost-effectiveness analysis, and mixed-methods studies were eligible. The analysis was descriptive.

Results

Of 5,567 records identified, 106 were included. Most of the studies included were conducted in the USA (n = 76), and a hospital or medical center was the most common setting (n = 82). Thirty-eight of the included studies calculated the costs of multiple imaging modalities; in studies with only one imaging modality included, conventional radiography was the most common (n = 32). Aggregated costs for low-value examinations amounts to billions of dollars per year globally. Initiatives to reduce low-value imaging may reduce costs by up to 95% without harming patients.

Conclusions

This study is the first systematic review of the cost of low-value imaging worldwide, documenting a high potential for cost reduction. Given the universal challenges with resource allocation, the large amount used for low-value imaging represents a vast opportunity cost and offers great potential to improve the quality and efficiency of care.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40258-024-00876-2.

Key Points for Decision Makers

Low-value imaging, imaging not affecting the patients’ further care and treatment, occupies resources in healthcare that could be used for high-value services.

The cost of low-value imaging could amount to billions of US dollars per year.

Measures for reducing low-value imaging are needed at all levels of healthcare.

Introduction

Diagnostic imaging is an essential part of modern patient management at all levels of healthcare [1]. The use and expenditures of healthcare services, including imaging, are increasing worldwide [1, 2]. According to the WHO, 3.6 billion imaging examinations are conducted each year, and 250 million of these are of children under the age of 15 years [3]. About 84% of examinations worldwide are conventional radiography and fluoroscopy (CR), while 8% are computed tomography (CT), about 4% ultrasound (US), 3% magnetic resonance imaging (MRI), and 1% nuclear medicine (NM) [4–7].

According to the Organization for Economic Co-operation and Development, 10‒34% of healthcare spending is wasteful and inappropriate [8]. Correspondingly, 20‒50% of imaging examinations have been reported to be inappropriate or of low value [8–11]. Low-value care is defined as services that provide little or no benefit to patients, have the potential to cause harm to patients, or waste limited healthcare resources [12]. Diagnostic imaging would be of low value when the examination has little or no impact on the management of the individual patient. Accordingly, it should not be confused with a negative examination result that might be valuable for ruling out serious conditions and preventing further health expenditures. From a societal perspective, low-value imaging constitutes increasing costs, while for the patient, it is an unnecessary risk due to exposure to ionizing radiation and/or contrast media [8–11]. Low-value imaging can be found across all imaging modalities [13], as well as in several patient groups [14], and is recognized as a major problem [1, 15]. Accordingly, recommendations, guidelines, and other measures have been issued to reduce its use. However, these measures often have a low impact on clinical practice as many barriers to reducing low-value services have been identified [16–22].

Imaging is a costly health service, and the number of examinations is rising [1]. Furthermore, in many countries, there is a lack of radiologists; thus, imaging could be a bottleneck in the healthcare system [1]. Low-value imaging examinations constitute a risk to patients, can reduce access to high-value care or delay crucial care, and result in poorer outcomes representing substantial opportunity costs.

Therefore, it is necessary to reduce the number of inappropriate or low-value examinations to free resources for high-value patient care. To do so, we need to know the resources used for low-value imaging. Accordingly, the objective of this systematic review was to provide an overview of the cost of low-value imaging worldwide.

Methods

This systematic review was conducted based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. The database search was developed in Medline—Ovid and further adapted to Embase-Ovid, Cochrane Library, and Scopus. The search terms were built from medical subject headings for Diagnostic imaging/Radiology, Health service misuse/Medical overuse, and Healthcare cost. Keywords were used for the concepts reduce/avoid and cost reduction. The complete search strategy and findings log can be found in the Online Supplementary Material (OSM) File 1. Searches were carried out in March 2022 with the last search on 15 March 2022. The search period was from 2012 to 2022 for the 10-year period in coherence with the activity of the choosing wisely campaign. Language filters were used to exclude papers written in languages other than English, German, Danish, Norwegian, and Swedish as these are the languages the authors are familiar with. Keywords were used to exclude studies on animals, mass screening, deep learning, other types of waste, or unnecessary care besides imaging.

Eligibility Criteria

Primary empirical studies assessing the costs of low-value diagnostic imaging were included. Studies designed as randomized controlled trials, non-randomized trials, cohort studies, cross-sectional studies, descriptive studies, cost analysis and cost-effectiveness analysis, and mixed-methods studies were included. The reference lists of relevant systematic reviews and meta-analyses were hand-searched for additional primary studies eligible for inclusion.

Selection of Records and Methodological Quality Appraisal

The records were archived using the Thomson Reuters EndNote X9.3.3 library, and duplicates were removed. All remaining records were transferred to Rayyan QCRI where additional duplicates were removed. All authors participated in the title and abstract screening using Rayyan. During the screening, records marked “Maybe” were discussed among the authors to agree on whether to include or reject them. All authors contributed to the full-text review and quality assessment of the studies. Due to the different methodologies of the included studies, the JBI critical appraisal tool was used for methodological quality assessment [23]. Any disagreements during abstract or full-text screening were resolved through discussion and consensus. During the full-text screening, reference lists of included articles were hand-searched for relevant articles. Google Scholar was used for hand searching for eligible papers that cited the included studies.

Data Extraction and Analysis

Data extraction was completed using a standardized summary table consisting of the following categories: author, title and year, country, design/methods, population, clinical setting, clinical indication for imaging, imaging modality, low-value imaging examination, control or comparator, cost/cost reduction, currency, the year costs were calculated, and cost denomination. All authors contributed to the data extraction. In addition, data extraction was discussed by the research team for quality assurance purposes.

Meta-analysis or comparison between studies or countries was not performed as reported costs are calculated differently in different studies, ranging from modeling to direct cost calculation. Just the cost of the index imaging study is included in the current review. For all results, the monetary value was converted to July 2022 US dollars using online converter calculators (https://www.oanda.com/currency-converter/en/?from=EUR&to=USD&amount=1) to provide an overview of costs in general. In studies where the year of cost calculation was not explicitly stated, we assumed the year costs were calculated was the same as the publication year.

Results

A total of 5,567 records were identified through database searches. 1,985 duplicates were removed, and 3,582 titles and abstracts were screened (Fig. 1). Hand-searching techniques resulted in the screening of 18 additional full-text records. In total, 166 reports were assessed for eligibility in full text, and of these, 60 records were excluded during full-text screening (OSM File 2 gives an overview of reasons for exclusion). In total, 106 studies were included in this review.

Fig. 1.

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram of selection of studies

The quality assessment, based on the JBI critical appraisal tool, resulted in no exclusion based on methodological issues, even though the quality of studies varied. Five types of checklists were used: RCT, cohort study, analytical cross-sectional studies, cost analysis, and quasi-experimental appraisal tools, depending on the design of the appraised study. The result of the quality appraisal is available in OSM File 3.

Characteristics of Included Studies

Table 1 presents the characteristics of the 106 included studies. Most studies employed a retrospective chart review/cohort design (n = 76), while six used a cross-sectional design. Another six studies were cost-effectiveness or cost analysis studies using modeling. The last 18 studies used different methodologies, from randomized controlled trials (n = 1) to mixed methods (n = 1). Most of the studies were conducted in the USA (n = 70), 17 studies were conducted in European countries, seven in Canada, five in Australia, and seven in other parts of the world, mainly Asian countries. The settings of most included studies were hospitals or medical centers (n = 82), while eight studies used multiple settings, and six were from an emergency department setting. Other settings included primary care/hospice (n = 4), intensive care unit (n = 4), and imaging center (n = 2).

Table 1.

Overview of setting and characteristics of the included studies

Author (year)	Country	Design/methods	Population in study	Clinical indication	Clinical setting	Low-value practice	Cost low-value in USD 2022
Conventional radiography and fluoroscopy
Birir et al. (2021) [24]	USA	Retrospective cohort study	1,258 patients	First total knee arthroplasty	Hospital	Routine post-operative X-ray	305 per examination
Brogi et al. (2017) [25]	Italy	Retrospective chart review	4,134 patients	Several	ICU	Imaging non-compliant with guidelines	57% cost reduction after intervention
Chui et al. (2018) [26]	Canada	Population-Based Retrospective Study	18,264 patients	Central venous catheter insertion	Hospital	Routine chest X-ray after US-guided central venous catheter insertion	115–200 per examination
Crawford et al. (2018) [27]	Canada	Decision modeling	-	Proximal humerus fractures	Hospital	Upper arm XR	38 per examination
Dempsey et al. (2017) [28]	USA	Retrospective chart review	170 patients	Primary total shoulder arthroplasty	Hospital	Routine postoperative X-ray	1,777 per examination
Diaz Vico et al. (2019) [29]	USA	Retrospective chart review	284 patients	Obesity	Hospital	Routine postoperative UGI contrast studies	687 per examination
Feng et al. (2016) [30]	USA	Retrospective chart review	101 patients	Mid urethral sling surgery	Hospital	Overuse in preoperative imaging	33 per examination
Gil-Borrelli et al. (2016) [31]	Spain	Retrospective cost minimization study	353 patients	Preoperative tests	Hospital	Imaging non-compliant with guidelines	22 per examination
Izamin et al. (2012) [32]	Malaysia	Cross-sectional design	9,420 x-rays	Several	Hospital	Routine chest x-ray	4.31 per examination
Jennewine et al. (2019) [33]	USA	Retrospective chart review	211 patients	Tibia plateau fractures	Hospital	Routine postoperative X-ray	496.29 per examination
Kempegowda et al. (2016) [34]	USA	Retrospective chart review	465 patients	Femur fracture	Hospital	Unnecessary follow-up	440 per examination
Keveson et al. (2017) [35]	USA	Before-after study	3,914 examinations	Invasive mechanical ventilation	ICU	Chest X-ray overutilization	228,756–267,678 savings per year
Ko et al. (2016) [36]	USA	Before-after study	> 1,000 chest X-rays	Patients in intensive care unit	ICU	Routine chest X-rays	52 per examination
Ling et al. (2018) [37]	Australia	Retrospective chart review	136 patients	Stable buckle distal radius fractures	ED	Serial X-ray	6,381 per month
Longenecker et al. (2016) [38]	USA	Retrospective cohort review	1,366 patients	Partial knee arthroplasty	Hospital	Immediate postoperative radiographs	41 per examination
Maldonado et al. (2018) [39]	USA	Retrospective chart review	470 patients	Breast cancer	Hospital	Short-interval follow-up mammogram	161 per examination
McCabe et al. (2021) [40]	UK	Retrospective chart review	101 patients	Cervical discectomy and fusion surgery	Hospital	Post-operative X-rays	101 per examination
McGrath et al. (2017) [41]	USA	Retrospective chart review	281 patients	Chest tube removal in children	Hospital	Chest X-ray after chest tube removal	303–535 per examination
Morden et al. (2014) [42]	USA	Retrospective chart review	13.8 mill beneficiaries	Several	Multiple	Short Interval DXA	20 million per year
Porter et al. (2021) [43]	USA	Quality improvement initiative	292 patients	Thoracic surgery	Hospital	Post thoracic surgery chest X-ray	106 per examination
Rafiq et al. (2017) [44]	Pakistan	Retrospective clinical audit	201 patients	Surgery	Hospital	Imaging non-compliant with guidelines	26 per examination
Richards et al. (2014) [45]	USA	Before-after study	100 patients	Preoperative test	Medical center	Preoperative chest x-ray	27 per examination
Ryan et al. (2019) [22]	Ireland	Retrospective chart review	1,124 patients	Multiple	Hospital	Imaging non-compliant with guidelines	10,769 per year
Sanchez Morales et al. (2019) [46]	USA	Retrospective chart review	246 patients	Clavicle fracture	Hospital	Follow-up X-ray	274 per examination
Stone et al. (2015) [47]	USA	Retrospective chart review	268 patients	Distal radius fractures	Hospital	2-week postoperative X-ray	105 per examination
Tharao et al. (2015) [48]	Kenya	Cross sectional study	175 patients	Ankle fracture	Hospital	Imaging non-compliant with guidelines	30 per examination
Tufescu (2017) [49]	Canada	Randomized controlled trail	90 patients	Stable fracture fixation	Hospital	Routine screening after fixation	35 per examination
Vicente-Guijarro et al. (2020) [50]	Spain	Descriptive observational study	3,449 chest X-rays	Chest X-rays	Hospital	Routine preoperative chest X-ray	28 per examination
Werner et al. (2016) [51]	USA	Retrospective chart review	599 patients	Anterior cruciate ligament reconstruction	Hospital	Routine X-ray postoperative	706 per examination
Woodland et al. (2018) [52]	USA	Retrospective chart review	200 patients	Central venous catheter insertion	Hospital	Routine chest X-ray	553 per examination
Wrotek et al. (2019) [53]	Poland	Retrospective chart review	166 patients	Bronchiolitis [children]	Hospital	Routine chest X-ray	468 per examination
Wu et al. (2020) [54]	USA	Before-after study	6,441 chest X-rays	Several	ICU	Daily chest X-ray	175 per examination
Computed tomography
Behmanesh et al. (2019) [55]	Germany	Retrospective, single-center study	439 patients	Hydrocephalus	Hospital	Follow up CT after shunt	164 per examination
Benayoun et al. (2016) [56]	USA	Retrospective cross-sectional study	3,753 patients	Cervical spine injury	Hospital	Cervical spine CT	17,802–31,216 per 6 months
Hayatghaibi et al. (2021) [57]	USA	Retrospective chart review and cost analysis	3,186 examinations	Emergency patients	Hospital	Non-contrast head CT	204,019 per year for inappropriate examinations
Kothari et al. (2019) [58]	USA	Retrospective chart review	405 patients	Acute uncomplicated pancreatitis	Hospital	CT in the ED after clinical and biochemical evidence of pancreatitis	5,094 per examination
Martyak et al. (2018) [59]	USA	Retrospective chart review	143 patients	Mild traumatic brain injury	Hospital	Routine use of head CT	95% cost reduction
Miller et al. (2012) [60]	USA	Retrospective chart review	83 patients	Soft tissue sarcomas	Hospital	CT for low- and intermediate-grade soft tissue sarcoma	2,003 per examination
Parma et al. (2014) [61]	USA	Retrospective chart review	438 cases	Head injury	Hospital	CT for minor head injury	1,745 per examination
Quick et al. (2013) [62]	USA	Retrospective chart review	95 patients	Trauma	Hospital	Repeated CT	52 per examination
Sharma et al. (2019) [63]	USA	Retrospective chart review	217 patients	Orbital floor fracture	Hospital	Postoperative CT	172 per examination
Stewart et al. (2020) [64]	USA	Retrospective chart review	1,000 patients	Facial trauma	Hospital	Imaging non-compliant with guidelines	1,419 per examination
Westfall et al. (2021) [65]	USA	Retrospective chart review	1,007 patients	Acute appendicitis	Hospital	Abdominal CT	870 per examination
Ultrasound
Al Darrab et al. (2021) [66]	Kingdom of Saudi Arabia	Retrospective chart review	670 referrals	Undescended testis	Hospital	US before treatment	54 per examination
Chamberlain et al. (2017) [67]	USA	Retrospective, single-institution study	539 patients	Chest pain in children <18 years old	Hospital	Imaging non-compliant with guidelines	56,805 per year
Jawa et al. (2021) [68]	Canada	Interrupted time series	241 patients	Multicystic dysplastic kidney or solitary kidney [children]	Hospital	Serial renal US with variable frequency	340.21 per examination
Maurer et al. (2012) [69]	Germany	Retrospective chart review	176 patients	Polytrauma	Hospital	Abdominal ultrasound follow-up	49 per examination
Mouawad et al. (2015) [70]	USA	Retrospective chart review	572 patients	Deep venous thrombosis	Hospital	Duplex venous scanning	967,098 per study population
Mousa et al. (2015) [71]	USA	Retrospective chart review	360 patients	Deep venous thrombosis	ED	Duplex venous scanning	1,256 per examination
Mousa et al. (2018) [72]	USA	Retrospective chart review	1,909 patients	Deep venous thrombosis	Hospital	Duplex venous scanning	1,899 per examination
Thompson et al. (2021) [73]	USA	Cost-effectiveness analysis	374 patients	Syncope	Primary care	Echocardiogram	833 per examination
Magnetic resonance imaging
Amin et al. (2019) [74]	USA	Cost-Effectiveness Analysis	–	Meniscal Tears of the Knee	Hospital	Knee MRI	1,863 per examination
Babbel et al. (2012) [75]	USA	Retrospective chart review	62 patients	Upper extremity condition	Multiple	MRI to determine the validity of patient reported problem	1,003 per examination
Castillo et al. (2021) [76]	USA	Retrospective chart review	322 patients	Low back and tail bone pain	Hospital	MRI sacrum	5,292 per examination
Cortes et al. (2019) [77]	USA	Prospective study	51 patients	Rotator cuff tendinopathy	Hospital	Premature MRI	4,786 per examination
Dookeran et al. (2021) [78]	USA	Retrospective chart review	1,472,236 patients	Preterm infants—head MRI	Hospital	Brain MRI among infants with gestational age <= 36 weeks	559,825–1,286,225 cost reduction per year
Flaherty et al. (2019) [79]	USA	Retrospective chart review	514,049 records	Several	Multiple	Imaging non-compliant with guidelines	MRI 754–854 per examination
Issa et al. (2014) [80]	USA	Prospective single center cohort study	21,837 patients	Hip pain	Hospital	MRI hip	149–305 per examination
Jahanmehr et al. (2019) [81]	Iran	Descriptive‐analytic study	614 patients	Lumbar vertebrae disorders	Hospital	Imaging non-compliant with guidelines	19.23 per examination
Kavosi et al. (2021) [82]	Iran	Cross-sectional study	385 patients	Several	Hospital	Imaging non-compliant with guidelines	119,378 per year
Khan et al. (2021) [83]	UK	Retrospective chart review	87 patients	Knee pain	Hospital	Imaging non-compliant with guidelines	18,126 per consultant per year
Klein (2017) [84]	USA	Retrospective chart review	81 patients	Low back pain	Imaging center	MRI within 12 months after abdominal CT	1.4–4 billion savings per year nationally
Martin et al. (2012) [85]	USA	Retrospective chart review	320 patients	Musculoskeletal tumors	Hospital	Prereferral MRI	732 per examination
Michelotti et al. (2018) [86]	USA	Retrospective chart review	140 patients	Wrist ligamentous injury	Hospital	Wrist MRI	2,571 per examination
Pozo-Rosich et al. (2020) [87]	Spain	Mixed method study	3,507 records	Headache	Hospital	Imaging non-compliant with guidelines	305 per examination
Sheridan et al. (2021) [88]	Ireland	Retrospective cohort study	109 MRI scans	Knee pain	Hospital	MRI for elderly patients	261 per examination
Nuclear medicine
dos Santos et al. (2016) [89]	Brazil	Cross-sectional study	190 patients	Coronary artery disease	Hospital	Imaging non-compliant with guidelines	78,346 cost savings per year
Krill et al. (2012) [90]	USA	Retrospective chart review	25 patients	Solitary kidneys [prenatal]	Hospital	Routine renal scintigraphy	599–937 per examination
Multiple modalities
Baugh et al. (2019) [91]	USA	Prospective multicenter cohort study	3,686 patients	Syncope	ED	Multiple	81 (CR) – 3531 (coronary angiography) per examination
Bledsoe et al. (2017) [92]	USA	Retrospective chart review	163 scans	Trauma patients	ED	Duplicate imaging	660–1,048 per examination
Boutis et al. (2015) [93]	Canada	Prospective study	2151 patients	Acute ankle injuries	ED	Imaging non-compliant with guidelines	CR 80 CT 116 MRI 134 per examination
Cheung et al. (2019) [94]	USA	Root cause analysis and intervention	21 patients	Fungemia in children	Hospital	Abdominal imaging and US	3,663 per examination
Cooper et al. (2013) [95]	USA	Retrospective chart review	101 patients	Solid tumor of the pancreas	Hospital	Imaging non-compliant with guidelines, preoperative	4,235 per examination
Cristofaro et al. (2012) [96]	Italy	Retrospective chart review	4,018 requests	Several	Hospital	Imaging non-compliant with guidelines	31 per examination
De Roo et al. (2020) [97]	Belgium	Prospective study	633 patients	Low back pain	Hospital	Imaging non-compliant with guidelines	13,569 per year for inappropriate examinations
Falchook et al. (2014) [98]	USA	Retrospective chart review	47,224 patients	Prostate cancer	Hospital	Bone scan in low- and intermediate-risk patients	11,854,367 per year
Fields et al. (2015) [99]	USA	Retrospective cohort study	178 patients	Fall	Hospital	Imaging in inpatient falls	66,222 per year
Frisse et al. (2012) [100]	USA	Retrospective chart review	31,596 records	Several	ED	Multiple	CR 98 CT 530–618 per examination
Gupta et al. (2014) [101]	Australia	Retrospective chart review	219 patients	Oncology inpatients	Hospital	Oncology inpatient investigations	7,023 total during study period
Hill et al. (2015) [102]	USA	Retrospective chart review	513 patients	Trauma	Hospital	Duplicate CT/X-ray	120,000 per year
House et al. (2021) [103]	USA	Cross-sectional study	621,633 patients	ED and hospitalized children	Hospital	Multiple	>10,260,259 per year for inappropriate examinations
Johnson et al. (2014) [104]	USA	Retrospectively chart review	167 patients	Syncope	Hospital	Imaging non-compliant with guidelines	1491.61 per examination
Jung et al. (2015) [105]	USA	Retrospective chart review	12,620 patients	Several	Hospital	Repeat imaging	40,080 cost savings per year
Kazemian et al. (2021) [106]	USA	Retrospective chart review	115 patients	Uncomplicated Bell’s palsy	Hospital	Imaging non-compliant with guidelines	CT 668 MRI 1,208 per examination
Keidar et al. (2021) [107]	USA	Cross-sectional review	147 scans	Bilateral presbycusis [> 70 years old]	Hospital	Scans that did not ultimately change surgical planning	33,991 per study population
Kim et al. (2015) [108]	Australia	Retrospective chart review	236 patients	Prostate cancer	Hospital	Staging CT of the abdomen and pelvis and whole-body bone scan in asymptomatic low and intermediate-risk patients	73,719 per study population
Kushwaha et al. (2018) [109]	USA	Retrospective chart review	799 patients	Women with breast pain	Imaging center	Multiple	382 per examination
Mafi et al. (2017) [110]	USA	Retrospective chart review	1.7 mill examinations	Several	Multiple	Multiple	2,056 average per examination
Massa et al. (2018) [111]	Italy	Retrospective chart review	541 patients	Advanced cancer	Hospice	Imaging near death	> 700,000 per year
Massa et al. (2017) [112]	Italy	Retrospective chart review	2,516 examinations	Breast cancer	Hospital	Imaging in breast cancer care	123,278 per year
McAlister et al. (2018) [113]	Canada	Retrospective cohort study	162,143 patients	Several	Multiple	Multiple	399 per examination
McGowan et al. (2019) [114]	USA	Retrospective chart review	104 instances	Compression fracture treatment	Hospital	Follow-up	CT 57–63 MRI 85–127 Plus Professional charges 325–343 per examination
Morgan et al. (2019) [115]	Australia	Time-series analysis	1,119,796 CT scans	Low back pain	Primary care	Imaging non-compliant with guidelines	169 per examination
Mortimer et al. (2013) [116]	Australia	Cost-effectiveness analysis	–	Low back pain	Primary care	Imaging non-compliant with guidelines	CR 74 CT 211 average per examination
Nayeri et al. (2015) [117]	USA	Retrospective cohort study	45 patients	Meningioma	Hospital	Postoperative imaging surveillance	CT 412 MRI 7,034 per examination
Pellet et al. (2016) [118]	USA	Retrospective review	113 patients	Breast cancer	Hospital	Routine staging	146,863 total cost
Pistolese et al. (2013) [119]	Italy	Retrospective chart review	3,950 requests	Breast disease	Hospital	Breast imaging	22,252 per month
Prasad et al. (2012) [120]	USA	Population based observational cohort study	30,183 men	Prostate cancer	Multiple	Newly diagnosed prostate cancer	Bone scan 307 CT 553 per examination
Redd et al. (2017) [121]	USA	Retrospective chart review	442 patients	Pediatric syncope	Hospital	Imaging non-compliant with guidelines	CT 44,732 MRI 182,143 total in study
Shah et al. (2020) [122]	USA	Retrospective chart review	35 patients	Lymphedema praecox	Hospital	Other imaging than US	CR 390 NM 1,479 MRI 7,000
Thavorn et al. (2016) [123]	Canada	Retrospective chart review	22,811 patients	Breast cancer	Hospital	Routine imaging	783,306–1,217,270 per year
Trofimova et al. (2020) [124]	USA	Retrospective chart review	3,098 patients	Headaches [children]	Hospital	Imaging non-compliant with guidelines	398,109 total societal cost
Vilar-Palop et al. (2018) [125]	Spain	Cross-sectional retrospective study	2,022 examinations	Several	Hospital	Imaging using X-rays in general	42 average per examination
Wilson et al. (2015) [126]	USA	Retrospective chart review	121 patients	Long-bone cartilaginous lesions	Hospital	Advanced imaging	1,776 per examination
Winn et al. (2022) [127]	USA	Simulation modeling	–	Prostate cancer	Multiple	Imaging in prostate cancer patients	488 per examination
Wintermark et al. (2021) [128]	USA	Cost analysis	4,709 cases	Several	Multiple	CT Angiography for pulmonary embolism, adnexal cyst imaging follow-up, advanced imaging for low back pain	45–73% cost reduction

ED Emergency Department, ICU Intensive Care Unit, CR conventional radiography, CT computed tomography, MRI magnetic resonance imaging, US ultrasound, NM nuclear medicine

Sixty-eight studies assessed a single imaging modality, CR (n = 32), MRI (n = 15), CT (n = 11), US (n = 8), and NM (n = 2), while 38 studies assessed the costs of multiple imaging modalities.

Cost of Low-Value Imaging

Sixteen studies reported on the aggregated costs of low-value imaging or possible annual cost reduction, illustrating the amount of healthcare resources spent on imaging without impact on patient management. An overview of the individual studies is presented in Table 2. The possible cost reduction or costs reported varies between setting and patient groups. However, the possible redistribution of resources would be worth billions of dollars globally.

Table 2.

Overview of annual spending on low-value imaging and possible annual savings if reducing low-value imaging in different settings and patient groups

Author/year	Country	Clinical indication/patient group	Reported cost of low-value imaging /possible cost reduction per year (2022 USD)
Chamberlain et al. (2017) [67]	USA	Children with chest pain in hospital (539 patients)	56,805
De Roo et al. (2020) [97]	Belgium	Imaging non-compliant with guidelines—Low back pain (633 patients)	13,569
Dookeran et al. (2021) [78]	USA	Brain MRI among infants with gestational age ≤ 36 weeks (1,472,236 patients)	559,825–1,286,225
dos Santos et al. (2016) [89]	Brazil	Coronary artery disease—Imaging non-compliant with guidelines (190 patients)	78,346
House et al. (2021) [103]	USA	Children in ED/hospital (49 hospitals in the USA)	> 10 million
Falchook et al. (2014) [98]	USA	Prostate cancer low/intermediate risk (Nationally)	> 11 million
Gupta et al. (2014) [101]	Australia	Inpatients in oncology department (1 hospital)	30,000
Hayatghaibi et al. (2021) [57]	USA	Hospital—head CT (3186 examinations)	204,019
Hill et al. (2015) [102]	USA	Trauma—duplicate imaging (513 patients)	120,000
Kavosi et al. (2021) [82]	Iran	Imaging non-compliant with guidelines (385 patients)	119,378
Klein (2017) [84]	USA	Low back pain—MRI within 12 months after abdominal CT (81 patients)	1.4–4 billion
Massa et al. (2018) [111]	Italy	Hospice patients last 3 months of life (cohort 541 patients)	> 700,000
Morden et al. (2014) [42]	USA	DXA screening (13.8 million beneficiaries)	20 million
Ryan et al. (2019) [22]	Ireland	Imaging non-compliant with guidelines (1124 patients)	10,769
Thavorn et al. (2016) [123]	Canada	Breast cancer—routine imaging (22,811 patients)	783,306–1,217,270
Trofimova et al. (2020) [124]	USA	Children—headaches Imaging non-compliant with guidelines (3098 patients)	398,109

USD US dollars

Based on the reported cost per examination of the included studies an overview per modality is presented in Table 3, both in terms of overall cost per modality and with examples of specific patient groups. Costs vary based on cost level in different countries and imaging techniques, for example, in MRI number of sequences and use of contrast media [22, 24, 26–34, 37–44, 46, 47, 50–53, 55–58, 60, 61, 63–75, 77–91, 95, 96, 99, 102, 104, 106–110, 112–114, 117–126].

Table 3.

Cost per imaging examination for low-value imaging per modality with some specific patient groups as examples

	Cost in USD 2022
Low-value practice in conventional radiography/fluoroscopy (CR)
Overall—CR	4.27–3,696.13
Routine postoperative or follow-up X-rays in orthopedics	404.31
Routine use of chest X-ray	226.44
Imaging in breast cancer	122.01
Imaging outside guidelines in syncope patients	1,035.59
Other	324.53
Low-value practice in computed tomography (CT)
Overall—CT	78.9–5157.46
CT imaging in relation to fractures/trauma	716.51
CT imaging in relation to oncology	633.03
CT imaging in relation to syncope	1,028.42
Other	1,388.92
Low-value practice in magnetic resonance imaging (MRI)
Overall—MRI	27.44–7,124.63
Musculoskeletal MRI	1,302.22
MRI in oncology patients	1,486.87
MRI in syncope	1,690.09
MRI in headache	579.06
Other	1,273.47
Low-value practice in ultrasound (US)
Overall—US	36.35–5397.80
US in oncology patients	295.64
US in syncope patients	1,407.97
Other	537.41
Low-value practice in nuclear medicine (NM)
Overall—NM	246.38–6,996.20
Oncology patients	1,708.02
Other	1,578.55

USD US dollars

Low-value CR imaging in the included studies was mostly routine use of musculoskeletal or chest x-rays (CXR) in pre-/post-operative follow-up examinations. However, mammography, angiography, gastrointestinal imaging, and bone density scans used routinely or in follow-up were also included [22, 24, 26–34, 37, 38, 40–44, 46, 47, 50–53, 91, 99, 102, 104, 109, 110, 113, 119, 122–125].

For CT and MRI, oncology, orthopedic, cardiovascular, and neurology patients were the dominating patient groups included, with routine examinations or imaging non-compliant with guidelines dominating the findings [55–58, 60, 61, 63–65, 74, 75, 77–88, 91, 95, 96, 99, 102, 104, 106–110, 112–114, 117–126].

In US, examinations in oncology and cardiovascular diseases were most common amongst the included studies [66–71, 73, 91, 95, 96, 104, 109, 112, 118, 119, 121, 123], while in NM, examinations for oncology patients were most common [89, 90, 95, 104, 108, 110, 111, 118, 120, 122, 123].

Possible Cost Reduction Through Initiatives in Practice

Four studies, including cost-reduction calculations of interventions to reduce the use of low-value imaging, showed that costs of lower back pain imaging could be reduced by 95% in Australia [115, 116], 73–83% in the USA [128], and up to 16% in Belgium without harm to patients [97]. When introducing an intervention to reduce the routine/daily use of CXR in the ICU, four studies showed a cost reduction of 20‒66% without affecting quality of care [25, 35, 36, 54]. Furthermore, the reduction of preoperative routine CXR reduced costs by 88% in one study [45]. For X-rays of ankle injuries, two studies found that using the guidelines could reduce costs by 7‒49% [48, 93]. One RCT study examining a simplified radiography follow-up regime after stable fracture fixations demonstrated a cost reduction of 65% [49]. Four studies, two in a hospital/Emergency Department setting [100, 105] and two specifically in trauma patients [62, 92] assessed the use of health information exchange to reduce imaging examinations. In trauma patients, a 37‒47% cost reduction was shown, while the changes in cost were small in the overall use of imaging, as some examinations increased in use while others were reduced. Other studies on various patient groups showed 34‒70% cost reduction [59, 94, 127, 128].

Discussion

This study is the first systematic review of the costs of low-value imaging globally. Given the universal challenges with resource allocation, this represents a vast opportunity cost and a great potential for providing high-quality services and improving the quality of care. Variation in access and use of imaging is found between and within countries and regions, indicating overuse in some areas and underuse in others. Low-value imaging is most common in areas with easy service access [129–134]. Thus, the potential opportunity cost and potential for improvement of the quality of services will vary.

Earlier research has identified specific clinical indications where low-value imaging is more prominent, such as atraumatic pain and routine imaging in minor head injuries, urolithiasis, trauma, thrombosis, and follow-ups [14]. This review demonstrates that some initiatives for reducing low-value imaging yield substantial cost reduction, as costs for low-value lower back pain imaging could be reduced by 95%, and preoperative routine CXR costs could be reduced by 88%. At the same time, other initiatives demonstrated less cost reduction (< 20%). Thus, some types of imaging have a higher potential for reducing costs, or there are differences in the success rate of the chosen intervention. The right combination of imaging to target and type of intervention can free resources for other high-value services, both in imaging and in other parts of the health services, by reducing cascaded unnecessary care [135]. This will improve the quality and efficiency of care and could help reduce healthcare emissions [136].

A systematic review of measures for reducing low-value imaging found that most initiatives focus on implementing guidelines and training referrers to reduce the number of inappropriate referrals to imaging [137], and that most initiatives target musculoskeletal, neuro, and vascular imaging. Several of the initiatives succeeded in reducing the use of imaging, at least for a short time. However, initiatives may need to target other parts of the health services than the referrer alone. To create sustainable change, it will be important to target low-value health service drivers broadly. As shown by Landon et al. [138], drivers of low-value services are complex and can be found at all levels: hospital, provider, and patient. Financial incentives, culture in the medical community, and intensity of care are especially strong drivers. Hence, measures addressing drivers on all levels of healthcare and imaging services are needed to tackle the challenge of low-value imaging.

Furthermore, some examinations are more resource intensive. For example, MRI and NM represent 3% and 1% of the total imaging volume, respectively. However, they have the highest overall costs per examination. This can be explained by the high costs of these examinations and the status and imperative of hi-tech imaging [139, 140]. Therefore, reducing low-value utilization of such examinations may result in great resources freed for high-value care.

Strengths and Limitations

As with all systematic reviews, this study depends on the content and quality of the included studies. According to our assessment, the quality of the studies varied, and results reported are thus of variable quality as well. In addition, the methodology used in the studies for calculating costs varied greatly. While some studies reported on thorough cost analysis, many reported costs as part of an overall objective, for example, estimates on cost reduction from a measure implemented at the hospital. Moreover, many different sources of cost data were used, such as direct and indirect cost calculations, fees, price lists at hospitals, or reimbursement amounts, permitting a large variation in reported costs. However, cost levels vary between healthcare systems and countries worldwide, which may be mirrored in the included studies. Furthermore, countries with underuse are possibly under-represented in this study but are also much less likely to have high rates of low-value care. Correspondingly, cost estimates are based on studies from countries that have documented higher rates of low-value imaging. The bias in the publications on cost may represent a “natural weighting” of the extent of low-value imaging as there are more publications from areas that are more concerned about low-value imaging and its opportunity cost.

As pointed out in the Methods section (Sect. 2), we estimated the year of cost calculation (publication year) for studies lacking adequate information. This may not be correct. However, the resulting errors may be small, as the yearly cost changes are small. For the proportion of low-value imaging, there may be relevant differences for the various modalities. Further, analysis is not possible based on this data set, however points to knowledge gaps urgently needing to be filled by further research.

Finally, a strength of this study is the use of the costs of specific low-value imaging examinations and not for imaging in general. Thus, the costs of low-value examinations were in all probability identified through this search strategy. In addition, while low-value care is a well-defined area in general, the efforts to reduce low-value healthcare have been hampered by the lack of consensus around a single definition for “value.” For example, imaging can be seen as valuable to calm people’s anxiety, i.e., due to its anxiolytic effect. In this review we have only considered direct, intended, and documented health effects as valuable. Moreover, we have, as has been suggested elsewhere [141, 142], included economic values in assessing low-value care.

Conclusions

This review documents the costs of low-value imaging amounts to billions of dollars worldwide and demonstrates vast opportunity costs and great potential to improve the quality and efficiency of health services. This potential will be greatest in areas with high utilization of low-value imaging. Drivers of low-value imaging should be addressed at all levels of healthcare to reduce low-value imaging and expedite access to high-value imaging. Hence, more knowledge is needed on costs, specific drivers, and effective measures for reducing low-value imaging and improving the quality of care.

Supplementary Information

Below is the link to the electronic supplementary material.

Declarations

Funding/Support

Open access funding provided by NTNU Norwegian University of Science and Technology (incl St. Olavs Hospital - Trondheim University Hospital). This work was supported by grant 302503 from the Norwegian Research Council. The funder had no role in the design and conduct of the study.

Conflict of Interest

Kjelle: No conflict of interest. Brandsæter: No conflict of interest. Andersen: No conflict of interest. Hofmann: No conflict of interest.

Ethics Approval

Not applicable.

Consent to Participate

Not applicable.

Consent for Publication (from patients/participants)

Not applicable.

Availability of Data and Material

Data extracted from the included papers are available in Online Supplementary Material File 4.

Code Availability

Not applicable.

Authors' Contributions

Kjelle: Planning, searching, screening, full-text screening, snowballing, analysis, drafting, and revision of the manuscript. Brandsæter: Planning, screening, full-text screening, snowballing, analysis, and manuscript revision. Andersen: Planning, screening, full-text screening, snowballing, analysis, and manuscript revision. Hofmann: Planning, screening, full-text screening, snowballing, analysis, and manuscript revision.