CT Abdomen With and Without Contrast Material

A targeted literature review was designed using relevant computed tomography (CT), abdomen and contrast media search terms. The search strategy was developed using Medical Subject Headings (MeSH) related to CT, abdomen as well as other relevant text words identified in a primary literature scan. Results were limited to studies written in English and conducted in humans in the past ten years. The search was developed to answer the following evidence questions: 1.) What is the evidence surrounding the utilization of CT Abdomen with and without contrast? 2.) What is the evidence that the utilization of CT Abdomen with and without contrast differs by patient characteristic? 3.) What is the evidence that utilization rates of CT Abdomen with and without contrast differ by location? 4.) What is the evidence surrounding the safety of contrast material use in CT Abdomen imaging procedures?

Profile of Evidence Brief Review and Discussion of Literature in National Quality Measures Clearinghouse, American College of Radiology, PubMed, and Cochrane Databases National Quality Measures Clearinghouse Our search of the National Quality Measures Clearinghouse (NQMC), using the search terms computed tomography, abdomen, and contrast media returned no relevant documents.

American College of Radiology Appropriateness Rating Our search of the American College of Radiology (ACR) database of appropriateness ratings, returned 30 documents relevant to the use of CT Abdomen with and/or without contrast media that were unique to the ACR.

PubMed A combination of search strategies including MeSH terms and text words was employed to identify the full range of literature for each of the key questions. The MeSH terms included: tomography, spiral computed; abdomen; and contrast media. Our searches in PubMed returned a total of 12 relevant studies.

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Cochrane Review Databases For our review of the Cochrane Review Databases, including the Cochrane Database of Systematic Reviews, the Health Technology Assessment Database, and the National Health Service (NHS) Economic Evaluation Database, we used the following MeSH search terms: tomography, spiral computed; abdomen; and contrast media. We were unable to identify any studies that were relevant to the key questions and unique to Cochrane (i.e., not included in the literature found in PubMed).

Magnitude and/or Importance of the Problem CT Abdomen is a very common advanced imaging procedure in the Medicare population. All three CT Abdomen procedures (those with contrast, those without contrast, and those with both) were in the top 30 most common advanced imaging procedures in the 2006 Medicare claims outpatient data. This measure calculates the percentage of abdomen studies that are performed with and without contrast out of all abdomen studies performed (i.e., those with contrast, those without contrast, or those with both). The intent of this measure is to assess questionable utilization of contrast agents that carry an element of risk and significantly increase examination cost. While there may be a direct financial benefit to the service provider for the use of contrast agents due to increased reimbursements for "combined" studies, this proposed measure is directed at the identification of those providers who typically employ interdepartmental/facility protocols that call for its use in nearly all cases. The measure identifies prevailing norms for the use of combined studies, as well as the providers that vary substantially from the norms, to document possible inefficient examination protocols. The measure seeks to promote the use of studies that are considered reasonable for the indication, while avoiding potentially harmful effects of unnecessary radiation and contrast exposure. The mistaken concept is that more information is always better. A combined CT study essentially doubles the radiation dose to the patient and exposes him/her to the potential harmful side effects of the contrast material itself. 1 Further, Medicare claims analyses show that a significant pattern of variation among high volume providers exists in the use of combination examinations in conjunction with CT Abdomen.

Overview of Existing Measures Our search of the NQMC yielded no quality measures relevant to CT Abdomen. In this section we provide an overview of our measure including the numerator and denominator statements, as well as the exclusion criteria used to calculate the measure. For full technical specifications of the measure please visit the QualityNet website: http://www.qualitynet.org.

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Public comment to the proposed measure. NQF. http://www.qualityforum.org/projects/ongoing/Imaging/comments_revised/view.asp

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Outpatient Imaging Efficiency Measure – CT Abdomen with and without Contrast Material Numerator Statement: The number of Abdomen CT studies with and without contrast (combined studies). Denominator Statement: The number of Abdomen CT studies performed with contrast, without contrast or both with and without contrast. Denominator Exclusions: Patients with diagnoses related to unspecified disorder of kidney and ureter, hematuria, pancreatic disorders, adrenal mass, malignant neoplasms of liver and intrahepatic bile ducts, and neoplasms of the pancreas, kidney, and liver.

Overview of Existing Guidelines Our search of the American College of Radiology database of appropriateness ratings identified 30 appropriateness criterion related to the use of CT Abdomen studies with and without contrast material. Of these relevant guidelines, 22 met the inclusion criteria for the measure (i.e., were not included in the denominator exclusions) including 57 different conditions (variants) where the use of CT Abdomen was evaluated. Below we provide summary tables of these criteria where appropriateness is rated on a scale of 1 to 9 with a score of 1 being least appropriate and 9 most appropriate (Table 1). Entries of NR indicate there was no ACR rating for CT Thorax with the indicated use of contrast material. Table 1: Included ACR Appropriateness Ratings 2 ACR Rating Condition

Acute Abdominal Pain and Fever or Suspected Abdominal Mass

Acute Onset Flank Pain Suspicion of Stone Disease

2

With Contrast

Without Contrast

With and Without Contrast

Postoperative patient with fever

8

7

NR

Postoperative patient with fever and no abscess seen on CT scan within the last 7 days

8

6

NR

Patient presenting with fever, nonlocalized abdominal pain, and no recent operation

8

6

NR

NR

8

NR

Variant

Suspicion of stone disease

ACR Appropriateness Criteria ® October 2008 Version. Reston, VA: American College of Radiology, 2009. Accessed July 24, 2009 at http://www.acr.org/SecondaryMainMenuCategories/quality_safety/app_criteria/pdf/TableofContents.aspx

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ACR Rating Condition

With Contrast

Without Contrast

With and Without Contrast

NR

7

NR

Stable patient

8

8

NR

Unstable patient

4

4

NR

Hematuria > 35 RBC/HPF (stable)

8

8

NR

7

NR

NR

7

NR

NR

Adult with known Crohn's disease; stable, mild symptoms

6

NR

NR

Newly diagnosed endometrial cancer; diagnostic work-up and staging

4

NR

NR

Superficial TCC - no invasion or risk factors

1

NR

3

Invasive TCC with or without cystectomy

5

NR

8

Superficial TCC - no invasion with risk factors

3

NR

8

NR

NR

7

NR

NR

9

NR

NR

9

5

5

NR

Variant Recurrent symptoms of stone disease

Blunt Abdominal Trauma 3

Crohn's Disease

Endometrial Cancer of the Uterus

Follow-up Imaging of Bladder Carcinoma

Jaundice

Adult; initial presentation (abdominal pain, fever, or diarrhea); Crohn's disease suspected Adult with known Crohn's disease and fever, increasing pain, leukocytosis, etc.

Acute abdominal pain; at least one of the following: fever, history of biliary surgery, known cholelithiasis Painless; one or more of the following: weight loss fatigue, anorexia, duration of symptoms greater than 3 months; patient otherwise healthy Painless; one or more of the following: weight loss fatigue, anorexia, duration of symptoms greater than 3 months; patient will not tolerate radical surgical procedure Clinical condition and laboratory examination make mechanical obstruction unlikely

3

Does not specify with or without contrast media

4

ACR Rating With Contrast

Without Contrast

With and Without Contrast

Confusing clinical picture; patient not described in previous scenarios

7

7

NR

Older patient with typical clinical presentation for diverticulitis

84

6

NR

Acute, severe, with or without fever

95

6

NR

Chronic, intermittent, or low grade

86

5

NR

Obese patient

87

5

NR

Typical benign on initial imaging, no history of malignancy

4

4

NR

Typical benign on initial imaging, known history of extrahepatic malignancy

5

5

NR

Indeterminate on initial imaging, >1 cm, no suspicion or evidence of extrahepatic malignancy or liver disease

8

8

NR

Small lesion on initial imaging, < 1cm

5

5

NR

Condition

Lower Left Quadrant Pain

Liver Lesion Characterization 8

Variant

Obstructive Voiding Symptoms Secondary to Prostate Disease

Normal renal function

NR

NR

1

Increased blood urea nitrogen (BUN) and/or creatinine

NR

NR

1

Palpable Abdominal Mass

NA

8

8

NR

Status post radical prostatectomy; rising PSA level

7

NR

NR

Status post radiation therapy; rising PSA level

7

NR

NR

Treatment of metastatic prostate cancer by androgen deprivation therapy (ADT); rising PSA level

7

NR

NR

Rectal cancer (small or superficial)

6

6

NR

Rectal cancer (large lesions)

8

8

NR

Post-Treatment Follow-up of Prostate Cancer

Pretreatment Staging of Colorectal Cancer

Oral and/or colonic contrast may be helpful for bowel luminal visualization Oral and/or colonic contrast may be helpful for bowel luminal visualization 6 Oral and/or colonic contrast may be helpful for bowel luminal visualization 7 Oral and/or colonic contrast may be helpful for bowel luminal visualization 8 Does not specify with or without contrast material 4 5

5

ACR Rating With Contrast

Without Contrast

With and Without Contrast

Colon cancer (other than rectum)

8

8

NR

NA

7

6

NR

With no underlying risk factors

NR

2

2

Recurrent Lower Urinary Tract Infections in Women

Patients who are nonresponders to conventional therapy, get frequent reinfections, and have underlying risk factors

NR

2

7

Renal Failure

Chronic renal failure

NR

3

NR

Fever, leukocytosis, and classic presentation clinically for appendicitis in adults

8

7

NR

Fever, leukocytosis; possible appendicitis, atypical presentation, adults and adolescents

8

6

NR

Fever, elevated white blood cell count, positive Murphy sign

5

5

NR

6

6

NR

7

7

NR

6

6

NR

Pretreatment staging of ovarian cancer

9

NR

NR

Rule out recurrent ovarian cancer

9

NR

NR

9

9

NR

9

NR

NR

8

NR

NR

Condition

Pulsatile Abdominal Mass

Right Lower Quadrant Pain

Right Upper Quadrant Pain

Staging and Follow-up of Ovarian Cancer Staging Evaluation Hodgkin's Lymphoma 9 Staging of Testicular Malignancy Suspected Small Bowel Obstruction

9

Variant

Suspected acalculous cholecystitis No fever, normal white blood cell count No fever, normal white blood cell count, ultrasound shows only gallstones

Elderly patient, any gender, with biopsy-proven CS IIIA MCHD, with a left supraclavicular node and single 2cm retroperitoneal node at L2 Testis tumor (diagnosed by orchiectomy) Suspected complete or high-grade partial small bowel obstruction: without oral contrast, with IV contrast

Does not specify with or without contrast media

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ACR Rating Condition

Variant Suspected complete or high-grade partial small bowel obstruction: with oral water soluble contrast, with IV contrast Suspected complete or high-grade partial small bowel obstruction: with oral dilute barium contrast, with IV contrast Suspected intermittent or lowgrade small bowel obstruction: without oral contrast, with IV contrast Suspected intermittent or lowgrade small bowel obstruction: with oral water soluble contrast, with IV contrast Suspected intermittent or lowgrade small bowel obstruction: with oral dilute barium contrast, with IV contrast

With Contrast

Without Contrast

With and Without Contrast

5

NR

NR

5

NR

NR

4

NR

NR

7

NR

NR

7

NR

NR

Of the 57 included variants, only 10 provide a recommendation on the appropriateness of CT Abdomen with and without contrast. Of these 10, 4 receive a rating below 5 with 2 receiving the lowest score of 1. The remaining 47 variants do not provide a rating for the use of CT Abdomen with and without contrast, indicating that this procedure is not recommended for use in these variants. In addition to the aforementioned guidelines, we identified 10 guidelines, including 22 variants that related to the use of CT Abdomen studies with and without contrast material but that met the exclusion criteria for our measure. Below we provide summary tables of these excluded criteria (Table 2).

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Table 2: Excluded ACR Appropriateness Ratings 10 ACR Rating Condition

With Contrast

Without Contrast

With and Without Contrast

6

6

NR

7

7

NR

8

8

NR

Severe abdominal pain, elevated amylase lipase, fever and elevated white blood cell count

9

9

NR

Severe abdominal pain, elevated amylase lipase, hemoconcentration, oliguria, tachycardia

9

9

NR

Uncomplicated patient

NR

1

1

Complicated patient (e.g., diabetes, immunocompromised, history of stones, prior renal surgery, not responding to therapy)

NR

5

8

Variant Etiology unknown, first episode of pancreatitis

Acute Pancreatitis

Severe abdominal pain, elevated amylase lipase, no fever or evidence of fluid loss at admission; clinical score pending Severe abdominal pain, elevated amylase lipase, 48 hours later assuming no improvement or degradation

Acute Pyleonephritis

Follow-up of Renal Cell Carcinoma

Asymptomatic patient; no known metastases

8

NR

NR

4

4

8

Hematuria 11

All patients expect those with generalized renal parenchymal disease or young female patients with hemorrhage cystitis Due to generalized parenchymal disease

2

2

2

ACR Appropriateness Criteria ® October 2008 Version. Reston, VA: American College of Radiology, 2009. Accessed July 24, 2009 at http://www.acr.org/SecondaryMainMenuCategories/quality_safety/app_criteria/pdf/TableofContents.aspx 11 Does not specify with or without contrast media 10

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ACR Rating With Contrast

Without Contrast

With and Without Contrast

No history of malignant mass; mass < 3 cm in diameter

8 12

8 13

NR

No history of malignant mass; mass 3-5 cm in diameter

8 14

8 15

NR

History of malignancy

8 16

8 17

NR

NA

NR

1

9

Typical malignant hepatic mass on initial imaging

6

6

NR

Indeterminate solitary mass on initial imaging, >1 cm, known history of extrahepatic malignancy

7

7

NR

Indeterminate solitary mass on initial imaging, >1 cm, known or suspected liver disease associated with a high risk of hepaticellular carcinoma (chronic hepatitis, cirrhosis, hemochromatosis, etc.)

8

8

NR

NR

NR

9 19

Condition

Incidentally Discovered Adrenal Mass

Indeterminate Renal Mass

Liver Lesion Characterization 18

Renal Cell Carcinoma Staging

Variant

Tumor 10 HU) or adrenal mass is discovered on early contrastenhanced CT 13 Presumes that a noncontrast CT has not already been performed 14 Indicated if noncontrast CT is indeterminate (density > 10 HU) or adrenal mass is discovered on early contrastenhanced CT 15 Presumes that a noncontrast CT has not already been performed 16 Indicated if noncontrast CT is indeterminate (density > 10 HU) or adrenal mass is discovered on early contrastenhanced CT 17 Presumes that a noncontrast CT has not already been performed 18 Does not specify with or without contrast media 19 Should include pre- and post-contrast phases including arterographic phase 12

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ACR Rating With Contrast

Without Contrast

With and Without Contrast

Tumor > 3cm

NR

NR

9 20

Renal Failure

Acute renal failure, unspecified

NR

3

NR

4

NR

NR

Renal Trauma

Blunt abdominal trauma with macroscopic hematuria with no suspicion of associated abdominal injury Blunt abdominal trauma; suspicion of multisystem trauma, with hematuria

8

NR

NR

Condition

Variant

Of the 22 excluded variants, only 4 do not have ACR appropriateness ratings for the use of CT Abdomen with and without contrast material. Within the remaining 18 variants, 7 have ratings for the use of CT Abdomen with and without contrast and 11 have ratings for the use of both CT Abdomen with contrast and CT Abdomen without contrast, indicating that either or both procedures are appropriate for use in these variants. There are certainly instances where it is necessary and appropriate to conduct an Abdomen CT with contrast in patients with some degree of renal insufficiency. Under such circumstances, clinicians proceed with extreme caution and conduct the contrast study taking into account the patient’s compromised renal functioning while balancing that with the need to perform a CT study with contrast (e.g., because the contrast will enhanced or emphasize certain anatomic structures, features, or “landmarks”). Although it is recommended that they be avoided in patients with moderate kidney failure, contrast materials such as intravenous iodinated contrast are useful in highlighting structures such as blood vessels that otherwise would be difficult to delineate from their surroundings. Using contrast material can also help to obtain functional information about tissues. The Abdomen CT Measure and associated exclusion criteria are not intended to imply that it is never appropriate to perform an Abdomen CT with contrast in a patient who has renal insufficiency. Rather, the issue is one of facilities where most or all of the patients receive a studies with and without contrast (combined studies) on the same day. While the Abdomen CT Measure assesses the number of Abdomen CT studies with and without contrast (combined studies) and is also intended to promote the use of imaging studies that are considered reasonable for the indication, there are several ACR appropriateness criterion that indicate that it is appropriate to perform Abdomen CT combined studies. For this reason, we exclude the majority of these indications from the measure. We further exclude 20

Should include pre- and post-contrast phases including arterographic phase

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patients with renal failure as these patients generally have a higher risk for kidneys damage. We feel that this is a necessary exclusion due to the appropriateness of combined studies for some indications.

Evidence Questions Key Question 1: What is the evidence surrounding the utilization of CT Abdomen with and without contrast material? Our search returned nine studies that provided information regarding the use of CT Abdomen with and without contrast material. Of these studies, five recommended the use of contrast media in certain indications, three recommended against the use of contrast media in certain indications, and one analyzes the patterns of use and radiation dose exposure due to CT scanning practices. Of the studies that recommended the use of contrast media in certain indications, one was an RCT, one was a diagnostic accuracy study, and three were prospective observational studies. The relevant RCT (n=71) compared the use of water to a dilute suspension of collagen as contrast media for imaging when disease is suspected within the stomach or proximal duodenum. This study found significantly more artifacts were caused by the use of water as contrast media than dilute collagen and recommended the use of a dilute suspension of collagen as contrast media when disease is suspected within the stomach or proximal duodenum. 21 In a relevant study of diagnostic accuracy (n=228), readers were asked to interpret helical CT images of the appendix following oral contrast and intravenous contrast. The study found the diagnostic accuracy of helical CT for acute appendicitis improved significantly with the use of intravenous contrast material. 22 The remaining prospective observational studies found contrast enhanced images improved image interpretation, 23 increased diagnostic certainty, 24 and provided higher sensitivity 25 in imaging studies. Three studies, including one RCT, one diagnostic accuracy, and one retrospective observational study, recommended against the use of contrast media in CT Abdomen imaging studies. The relevant RCT (n=40) investigated the use of intravenous glucagon for imaging of the gastrointestinal tract. This study found that there were no significant differences in qualitative or quantitative data for the intervention and control groups and therefore intravenous glucagon

Ramsay DW, Markham DH, Morgan B, Rodgers PM, Liddicoat AJ. The use of dilute Calogen as a fat density oral contrast medium in upper abdominal computed tomography, compared with the use of water and positive oral contrast media. Clinical Radiology 2001;56(8):670-3. 22 Jacobs JE, Birnbaum BA, Macari M, et al. Acute appendicitis: comparison of helical CT diagnosis focused technique with oral contrast material versus nonfocused technique with oral and intravenous contrast material. Radiology 2001; 220(3):683-90. 23 Groves AM, Kayani I, Dickson JC, et al. Oral contrast medium in PET/CT: should you or shouldn't you? European Journal of Nuclear Medicine and Molecular Imaging 2005; 32(10):1160-6. 24 Tsushima Y, Yamada S, Aoki J, Motojima T, Endo K. Effect of contrast-enhanced computed tomography on diagnosis and management of acute abdomen in adults. Clinical Radiology 2002; 57(6):507-13. 25 De Lutio di CE, Pinto A, Merola S, Stavolo C, Romano L. Role of Spiral and Multislice Computed Tomography in the evaluation of traumatic and spontaneous oesophageal perforation. Our experience. La Radiologia Medica 2005; 109(3):252-9. 21

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is not routinely recommended for helical CT of the abdomen. 26 In a diagnostic accuracy study (n=118) comparing the agreement in assessment of helical CT of the abdomen and pelvis without and with oral contrast for acute abdominal pain in adult emergency department (ED) patients, concluded that non-enhanced CT should be considered in adult ED patients presenting with acute abdominal pain. 27 Similarly, in a retrospective observational study (n=125) of the performance of CT without oral contrast media for blunt abdominal trauma, the authors determined multi-detector row CT without oral contrast material is adequate for depiction of bowel and mesenteric injuries that require surgical repair as successful identification of internal injury was comparable with previously reported data for single-detector row helical CT with oral contrast material. 28 While the findings of these eight aforementioned studies were not contrary to the CT Abdomen Imaging Efficiency measure, none of these studies specifically investigated the use of CT Abdomen with and without contrast media and are therefore not directly relevant to the measure. In an additional retrospective observational analysis of CT scanning patterns of use and dose, researchers investigate trends in CT utilization, including the use of contrast material and repeat procedures on the same day. The study finds that 93% of CT Abdomen scans performed between 1990 and 1999 were done with intravenous contrast. The remaining 7% not using intravenous contrast were primarily done for evaluation of renal or ureteral calculi, a finding that is consistent with the rationale for the exclusion criteria in our measure. Additionally, for patients having CT Abdomen scans, 96% had more than one scan sequence on the same day. 29 The findings of this study are of concern as they indicate a high use of potentially hazardous contrast material and overutilization and duplicative use of imaging services related to CT Abdomen.

Key Question 2: What is the evidence that utilization rates of CT Abdomen with and without contrast material differ by patient characteristic? Our search returned no studies that investigated patient characteristics in the use of CT Abdomen with and without contrast material.

Key Question 3: What is the evidence that utilization rates of CT Abdomen with and without contrast material differ by location? Our search returned no studies that investigated geographic variation in the use of CT Abdomen with and without contrast material. Eisenstat RS, Gold BM, Goffner L, Fruauff AA, Pollack S, Katz DS. Intravenous glucagon: does it optimize evaluation of the gastrointestinal tract on helical CT? Clinical Imaging 2002; 26(6):408-13. 27 Lee SY, Coughlin B, Wolfe JM, Polino J, Blank FS, Smithline HA. Prospective comparison of helical CT of the abdomen and pelvis without and with oral contrast in assessing acute abdominal pain in adult Emergency Department patients. Emergency Radiology 2006; 12(4):150-7. 28 Stuhlfaut JW, Soto JA, Lucey BC, et al. Blunt abdominal trauma: performance of CT without oral contrast material. Radiology 2004; 233(3):689-94. 29 Mettler FA, Wiest PW, Locken JA, Kelsey CA. CT scanning: patterns of use and dose. Journal of Radiological Protection. 2000; 20:353-359. 26

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Key Question 4: What is the evidence surrounding the safety of contrast material use in CT Abdomen imaging procedures? Our search returned three studies that provided information regarding contrast material safety concerns in CT Abdomen imaging procedures including one RCT, one clinical trial and one review. The results of the studies provided mixed conclusions about the safety of contrast material; however, all three studies investigated different contrast materials in different organ systems. The relevant RCT (n=71) compared the use of water to a dilute suspension of collagen as contrast media for imaging when disease is suspected within the stomach or proximal duodenum. This study found significantly more artifacts were caused by the use of water as contrast media than dilute collagen and recommended the use of a dilute suspension of collagen as contrast media when disease is suspected within the stomach or proximal duodenum. 30 An additional clinical trial (n=22) investigated the induction of clinically relevant changes in thyroid function parameters of euthyroid patients as a result of iodine-containing contrast media by measuring mean thyroid stimulating hormone levels (TSH). The study found iodine-containing contrast media can induce transient subclinical hypothyroidism in euthyroid patients; however, TSH reaction seems to be dependent on the preexisting state of thyroid function. 31 A final review provided an overview of the potential advantages of using lowosmolar iodinated solutions as an oral contrast agent for CT Abdomen studies. The study indicated iohexol may be an alternative to high-osmolar iodinated solutions or barium sulfate suspensions in certain clinical indications due to high frequency of nausea, vomiting, diarrhea and other adverse events as a result of the latter two contrast materials. 32

This material provided by FMQAI, the Medicare Quality Improvement Organization for Florida, an agency of the U.S. Department of Health and Human Services, was prepared by The Lewin Group, Imaging measure writers under contract with the Centers for Medicare & Medicaid Services (CMS). The contents presented do not necessarily reflect CMS policy. FL2009HODT8A1411406

Ramsay DW, Markham DH, Morgan B, Rodgers PM, Liddicoat AJ. The use of dilute Calogen as a fat density oral contrast medium in upper abdominal computed tomography, compared with the use of water and positive oral contrast media. Clinical Radiology 2001; 56(8):670-3. 31 Gartner W, Weissel M. Do iodine-containing contrast media induce clinically relevant changes in thyroid function parameters of euthyroid patients within the first week? Thyroid 2004; 14(7):521-4. 32 Horton KM, Fishman EK, Gayler B. The use of iohexol as oral contrast for computed tomography of the abdomen and pelvis. Journal of Computer Assisted Tomography 2008; 32(2):207-9. 30

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