Description of quantitative method(s)

CT AND SPECT ANALYSIS 1

CT and SPECT Procedures A statistical comparison of usage in MN hospitals

INTRODUCTION

Over the last few decades, the usage of diagnostic imaging in United States hospitals has been increasing. This rise in medical imaging contributes to both the increasing costliness of medicine and the amount of radiation patients are being exposed to while undergoing medical treatments. Of the many forms of medical imaging, computerized tomography (CT) and Single-photon emission computed tomography (SPECT) scans are some of the most prevalent. However, some studies have begun to show the use of SPECT procedures are slightly declining. (Smith-Bindman, Miglioretti, & Larson, 2008; Mettler, Wiest, Locken, & Kelsey, 2000; Muschlitz, 2011)

One study by Smith-Bindman, Miglioretti & Larson (2008) showed that CT usage has increased 14 percent per year, from 81 to 181 examinations, per 1000 patients. Subsequently, CT usage doubled over the ten year period in which the study was conducted. This increase was noted for all tested groups regardless of age, anatomic area scanned, and modality. Another report concluded that “in most large hospitals in the United States, CT scanning likely accounts for more than ten percent of diagnostic radiology examinations.” (Mettler, Wiest, Locken, & Kelsey, 2000) Mettler, Wiest, Locken and Kelsey (2000) noted that they found the largest percentage of scans was done in the 36-50-year-old age group. According the Minnesota Department of Health (MDH), the abundance of CT usage in the state is due to its ease of use during emergent situations; a CT scan can be provided within 25-45 minutes depending on positive or negative readings (Alberts et al., 2013).

While SPECT imaging has a well-defined role in medical diagnostic imaging, it tends to be most useful for Cardiovascular, stem cells, oncologic, neuroimaging applications. (Khalil, Tremoleda, Bayomy & Gsell, 2011) This may account fewer overall procedures performed. One study by Druz, Phillips and Sharifova (2011) evaluated 2005 SPECT appropriateness criteria in a diverse patient and physician population from a large regional medical center. An important finding was that appropriateness of SPECT was “strongly influenced by presence of symptoms, pre-test likelihood of disease, and Framingham risk scores.” (Druz, Phillips & Sharifova, sec 4, 2011) There was a strong trend for more appropriate studies in symptomatic patients and those at a greater likelihood of coronary artery disease (CAD), which is a recurring theme in SPECT usage analyzations. This study also showed that Cardiac Medical Doctors tend to refer fewer inappropriate SPECT procedures than do their counterparts in other specialties. Amen (b) et al (2011) further investigates the use of SPECT by limited numbers of clinicians and presents rationale for a more widespread use of SPECT in clinical practice for complex cases such as traumatic brain injury mapping and assessing other forms of cognitive decline. In Amen (a) et al’s 2013 study, they found that that the addition of brain SPECT imaging improved the diagnostic abilities and treatment process for 78.9% of patients studied and this percentage of patients reported improvements in a six month time period.

It is our intent to analyze the number of CT and SPECT procedures accomplished in hospitals in the state of Minnesota in the year 2013 to determine whether or not there was a significant difference in the number of CT and SPECT procedures performed.

HYPOTHESIS AND METHODOLOGY USED

The hypothesis we intend to prove is:

H0: The number of CT procedures performed in hospitals in the state of MN = the number of SPECT procedures performed in hospitals in the state of MN. 

H1: Number of CT procedures performed in hospitals ≠ the number of SPECT procedures performed in hospitals in the state of MN. 

The data set we will be using is taken from the Minnesota Health Care Cost Information System’s data concerning Imaging Procedures for the year 2013. The original data set can be found here: MN HCCIS Imaging Procedures 2013 (HCCIS, n.d.) This data set provides the frequency of use for medical imaging procedures, the facility type and name, and the location of the facility. The procedures included in the set are MRI, PET, CT, SPECT/CT and SPECT and also includes the total number of procedures for each facility. For this study we will be using only hospitals listed (numbering 212). We will also only include those hospitals reporting both CT and SPECT procedures, bringing our total number of hospitals to 81. For further information on MN medical imaging totals, you may go to the MN HCCIS website and find the complete listings of medical imaging procedure frequencies by year. (Minnesota Health Department, 2016)

We aim to determine the weather CT procedure usage is equal to the use of SPECT procedures in MN hospitals. To do this, we will begin with a cross tabulation method to create a contingency table which will organize our data. The cross tabulation will allow us to present the data in such a way that the interrelationships between data and the variables of that data can easily be determined. We will then use a t-test analysis to further examine the data and generate an accurate statistical analysis to determine if there is a significant difference between the means of our variables. (Chambliss, 2013)

To accomplish this analysis, our group will be using Microsoft Excel as our statistical software of choice. Excel is simple enough for the small data set that we will be examining and the software package already has statistical calculators built into the software. Our original data source is already in an Excel format, enabling ease of data input and transfer and creating additional data verification. Graphs and tables representing not only data, but also our analysis will likewise be easily created in Excel.

VARIABLES

Variable	Definition	Description of code	Source	Year
CT SCANS	Total number of CT scans performed at MN hospitals in 2013	Numeric	HCCIS	2013
SPECT SCANS	Total number of SPECT scans performed at MN hospitals in 2013	Numeric	HCCIS	2013

Source: MN HCCIS Imaging Procedures 2013

REFERENCES

Alberts, M., Wechsler, L., Lee Jensen, M., Latchaw, R., Crocco, T., George, M., & …Walker, M. (2013, November). Formation and function of acute stroke-ready hospitals within a stroke system of care recommendations from the Brain Attack Coalition. Stroke (00392499). doi: 10.1161/STROKEAHA.113.002285 Amen, D. G., Jourdain, M., Taylor, D. V., Pigott, H. E., & Willeumier, K. (a) (2013, Spring). Multi- site six month outcome study of complex psychiatric patients evaluated with addition of brain SPECT imaging. [Abstract]. Advances in Mind-body Medicine, 27(2), 6- 16. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/23709407 Amen, D. G., Trujillo, M., Newberg, A., Willeumier, K., Tarzwell, R., Wu, J. C., & Chaitin, B. (b) (2011). Brain SPECT Imaging in Complex Psychiatric Cases: An Evidence-Based, Underutilized Tool. The Open Neuroimaging Journal, 5, 40–48. http://doi.org/10.2174/1874440001105010040 Chambliss, D. F. (2013). Making sense of the social world: Methods of investigation, fourth edition. Thousand Oaks, CA: SAGE Publications, Inc. Retrieved from https://learn.umuc.edu/d2l/le/content/167112/viewContent/6874190/View Druz, R. S., Phillips, L. M., & Sharifova, G. (2011). Clinical Evaluation of the Appropriateness Use Criteria for  Single-Photon Emission-Computed Tomography: Differences by  Patient Population, Physician Specialty, and Patient Outcomes. ISRN Cardiology, 2011, 798318. http://doi.org/10.5402/2011/798318 Health Care Cost Information System (HCCIS). (n.d.). Retrieved November 17, 2016, from http://www.health.state.mn.us/divs/hpsc/dap/hccis/stndrdrpts.htm

Khalil, M. M., Tremoleda, J. L., Bayomy, T. B., & Gsell, W. (2011). Molecular SPECT Imaging: An Overview. International Journal of Molecular Imaging, 2011, 1-15. doi:10.1155/2011/796025

Mettler, F. A., Wiest, P. W., Locken, J. A., & Kelsey, C. A. (2000). CT scanning: Patterns of use and dose. Journal of Radiological Protection, 20(4), 353-359. doi:10.1088/0952- 4746/20/4/301

Muschlitz, L. (2011). Report shows nuclear medicine procedure volume slipping. Retrieved November 16, 2016, from http://www.auntminnie.com/index.aspx?sec=ser&sub=def&pag=dis&ItemID=96830

Smith-Bindman, R., Miglioretti, D. L., & Larson, E. B. (2008). Rising Use Of Diagnostic Medical Imaging In A Large Integrated Health System: The use of imaging has skyrocketed in the past decade, but no one patient population or medical condition is responsible. Health Affairs (Project Hope), 27(6), 1491–1502. http://doi.org/10.1377/hlthaff.27.6.1491