European Journal of Cardiovascular Medicine

Small bowel disease diagnosis has always been a problematic area for both radiologists and surgeons, owing to its length and the complexity of its nature¹. In the past, small intestinal imaging was done using barium studies, which produced inconsistent results. Even though ultrasonography has lower sensitivity for bowel pathologies, particularly in the small bowel, due to the scattering of ultrasound beams by air within the bowel. Fluoroscopic enteroclysis procedure is poorly tolerated because of the complicated process of time-consuming tube insertion and the additional dose of radiation exposure.² Small bowel capsule endoscopy is a valuable technique for detecting small bowel pathologies, but for its limitation to diagnose extraluminal pathologies and the restriction of endoscope passage beyond the point of obstruction/ stenosis.^2,3Hencenon-invasive Computed Tomography (CT)of abdomen is the primary imaging modality to look for small bowel pathologies and as  a resultof advances in Multi detector CT (MDCT)⁴ providing  good spatial / contrast resolution andpossibility of multiplanar reconstruction it has the benefit of evaluating the extraluminal causes. A contrast-enhanced abdominal CT using oral contrast allows proper assessment of the bowel as it is convenient and non-invasive. Bowel distension is necessary for CT bowel assessment to open up the collapsed loops that mask the underlying pathology^5,6. Adequate distention of the bowel lumen can be achieved by administering oral contrast agents which is required for wall thickness assessment with better visualization of wall characteristics. It also enables to distinguish the bowel from other soft tissues and provides optimal contrast between the bowel wall and the lumen^4,6,9-13.According to Macari M et al⁷, a minimum of 2 cm of bowel distention is required to be considered satisfactory. Rapid water absorption, prolonged gastric emptying, insufficient oral contrast agent consumption, and image acquisition shortly after oral contrast agent consumption can all lead to inadequate distension or luminal collapse⁸.

Oral contrasts can be negative, neutral, or positive depending on structural changes in the bowel to demonstrate pathological lesions. Negative oral contrasts include low-attenuation contrast agents such as air and carbon dioxide.¹⁴ Neutral oral contrasts likemannitol, low concentration (0.1% w/v) barium solution mixed with sorbitol, low-density barium (VoLumen) have attenuation value similar to that of water [10-30HU]^15-17. Positive contrast agents have a CT attenuation number more than that of enhancing structures includes iodinated contrast agents like Iohexol, Gastrografin (Meglumine diatrizoate and Sodium diatrizoate) and Barium sulfate etc.¹⁸

The most prevalent neutral contrast agent used extensively is water¹⁹. However, its utility is limited due to slow gut transit time of water, and clinical use for the distal parts of the small bowel is limited due to its rapid absorption^20-24. An ideal endoluminal contrast agent should cause uniform intraluminal attenuation, high contrast between bowel wall and luminal content, minimal mucosal absorption with maximum distension, no artifact formation and no significant adverse effects^11,28-30. By increasing osmolarity, additives like mannitol can slow water absorption and result in adequate bowel distension¹¹. Mannitol is a low-cost and easy-to-use neutral oral contrast agent which is proved to be effective in diagnosing Crohn's disease^25-27, neoplasms⁴ and bowel-ischemia¹².

There are multiple comparison studies done and the results concluded that mannitol was a better endoluminal contrast agent and also showed better bowel distension when compared against other contrast agents such as water, meglumine diatrizoate and meglumine ioxithalamate^{3,6,32,33,36-38}.The use of mannitol improved overall image quality as it provided better bowel distension uniformity, fold visibility, uniformity of the luminal content and delineation of the bowel wall to the lumen^6,32,33,37. In terms of palatability and tolerability, taste of mannitol was considered suitable and only few patients around 16% had mild diarrhea^{11, 31, 32, 34,35,37,38}.

The current study assessed and compared the quantitative and qualitative evaluation of bowel with diluted mannitol with water and diluted iodine-based diatrizoate meglumine as oral endoluminal contrast agents with regard to bowel distension, uniformity of bowel distension, mucosal fold/bowel wall visibility and homogeneity of luminal contents.

Study design: A prospective comparative study was done for a period of 2 years from July 2019 to June 2021 in a tertiary care hospital. The study subjects were referred to the Department of Radio-diagnosis for a CT of the abdomen and pelvis for various indications. The sample size was calculated using the formula n= z²pq/d^2, where z (at 95% confidence levels) = 1.96, p= 0.55, q= (1-p) = 0.45 and d (Precision taken) = 10%. Using this formula, the sample size came up to 96. It was remarked that present study involved a sample size of 108, for better inference.

Quantitative and Qualitative analysis of the bowel by two endoluminal contrast agents viz. diluted mannitol and iodine with an objective to compare their performance. Subjects between 18-50 years of age are included in this study(better compliance for drinking oral endoluminal contrast media ) and the exclusion criteria includes subjects with bowel obstruction, patients with poor compliance for drinking oral endoluminal contrast media as per our protocol, previous history of bowel surgery, patients on laxatives during the period of study, patients on pharmacological agents affecting bowel motility like tricyclic antidepressants, phenobarbitone or opioids, pregnant patients, patients with known allergy to iodine containing contrast agents and patients with serum creatinine levels >1.4 mg/dl. Random Sampling was done following ethics committee approval. Written informed consent was taken from the patients to participate in this study.

Data collection: The subjects were divided into 2 groups with 54 subjects in each group.

Group 1: received diluted iodinated contrast with water as oral endoluminal contrast media [40 ml of diatrizoate meglumine solution (65%) in 1960 ml of water] resulting in iodine strength of 0.7g of iodine in 100 ml (0.007%) dilution and Group 2 received 60g of mannitol dissolved in 2000 ml of water (300 ml of mannitol [20%w/v] in 1700 ml of water to make 3% solution of mannitol). Imaging of all cases were done from the diaphragm to the pubic symphysis using 128 slice MDCT(GE optima 660). All the patients were administered oral contrast in empty stomach (at least for 3-4 hours) and were instructed to consume 1500 ml of oral contrast within 45 minutes (250 ml every 5minute). The remaining 500 ml were given on the table just before scanning. Multiphasic study was performed depending on the clinical and radiological indications. Following the acquisition of topogram and non-contrast images, the post-contrast image acquisition was done after administration of intravenous contrast (IV contrast)- Iohexol containing 350 mg of iodine / ml (Omnipaque 350, GE Healthcare) at a dose of 1 ml/kg body weight and injection rate of 3.5 ml/sec. A bolus tracking method was used for acquiring images with pre – monitoring at the level of diaphragm and contrast triggering at the abdominal aorta upon achieving 100 HU for late - arterial phase, followed by 50 – 60 and 120-seconds delay for the portal venous and hepatic venous phases respectively. All images were acquired at 0.625 mm thickness and parameters of each of the phases were 120 kv and 110–380 smart mA of tube current using current modulation software, 0.625mm collimation and a pitch of 1.0.Image data was reconstructed in axial, sagittal, and coronal planes and analyzed using isotropic multi-planar reconstructions on AW server version 2.0.

Study methodology: The abdomen was divided into 4 quadrants by two imaginary lines on the coronal plane with a vertical imaginary line drawn from the xiphoid process of the sternum to the pubic symphysis and a horizontal line drawn passing through the midway of L3 vertebra forming upper and lower quadrants on both right and left sides. The CT findings were described as, A: Maximum bowel distension, which was taken in each quadrant and then average maximum bowel distension was calculated (in mm)among the mannitol and iodine groups; B:Bowel distension uniformity was assessed as poor, satisfactory and excellent - if <25%,25-75% and >75% of bowel loops respectively are optimally distended (> 18 mm) in all four quadrants and then overall bowel distension uniformity for all the quadrants was assessed among the mannitol and iodine groups; C:Mucosal fold/ wall visibility was assessed as poor, satisfactory and excellent if <25%,25 - 75% and >75% of bowel loops respectively show good visibility of mucosal fold/wall in all four quadrants and then overall mucosal fold visibility for all the quadrants was assessed among the mannitol and iodine groups; D: Homogeneity of Luminal Contents was assessed as poor, satisfactory and excellent – if <25% , 25 - 75%  and>75%  of bowel loops respectively show good homogeneity of luminal contents in all four quadrants and then overall homogeneity of luminal contents for all the quadrants was assessed for mannitol and iodine groups.

Statistical Analysis: MS Excel and SPSS version 23 (IBM SPSS Statistics) were used to analyse data.MS Excel and MS word was used to obtain various types of graphs anddiagrams, P value (Probability that the result is true) of <0.05 was considered as statistically significant after assuming all the rules of statistical tests.Categorical data was represented in the form of frequencies and percentages. Continuous data were expressed as mean ± standard deviation (SD). Chi square test of independence was used for finding the significance of categorical data in mannitol and iodine group and independent t-test were used for analyzing the mean difference between two quantitative variables in two groups.

Demographic features of the study group: Of the 108 patients, 62 (57.4%) were males and 46 (42.6%) were females. 32 (51.6%) of the males consumed mannitol and 30 (48.4%) consumed iodine. 22 (47.8%) of the females, consumed mannitol and 24 (52.2%) consumed iodine. General characteristics of patients such as gender distribution, age distribution are asin the tables -1 A and B. In this study, majority of the patients were between 26 to 55years.Abdominal pain was the most common symptom (Figure 1) followed by vomiting, fever, abdominal distension, etc.

Table1:A. Gender distribution among study groups B. Age categorization among study groups

Figure-1

Quantitative Analysis: The mean of maximum and overall average bowel distension among the mannitol and iodine groups is shown in Table 2. It is found that there was a significant mean difference in the mannitol and iodine groups (p<0.001). The mean of maximum distension of the small bowel with the mannitol group was higher compared to the iodine group in all the quadrants of the abdomen and was highest in the left lower quadrant and was lowest in the right lower quadrant in both mannitol-water and iodine-water groups. The overall average of mean bowel distension was also higher in the mannitol group than in the iodine group (p<0.001) – images 1 and 2 for mannitol group;3 and 4 for iodine group.

Table -2

Images 1 and 2: Maximum dsistension of bowel in the mannitolgroup : 1. In the right upper quadrant and 2. Distension of ascending colon

Images 3 and 4: Maximum dsistension of bowel in the Iodinegroup : 3. In the right upper quadrant and 4. Distension of ascending colon

1. Qualitative analysis
2. Bowel distension uniformity:

From the table 3, it can be concluded that there was a significant difference between the mannitol and iodine groups for uniform bowel distension with a greater number of cases showing excellent uniformity in bowel distensibility among the mannitol group in all quadrants, compared to the iodine group, predominantly among the bowel loops in the right lower quadrant followed by left upper quadrant (images 5 and 6).            

Patients who received mannitol had higher number of quadrants showing excellent bowel uniformity (80/216) than the iodine group (42/216), whereas least number of quadrants showing poor uniformity of bowel distensibility noted amongst the mannitol group (21/216).(Table 4).

Images 5 and 6: Uniform bowel dsistension 5. Excellent in the mannitol group and 6. Satisfactory in the iodine group

Mucosal fold visibility: In comparison to the mannitol group, the majority of the patients in the iodine group had poor mucosal fold visibility in all four quadrants, more so in the right upper quadrant (40/102 quadrants of poorly visualized bowel). However, no statistically significant difference observed between the mannitol and iodine groups with regard to satisfactory mucosal fold visibility (Table 5). Excellent mucosa fold visibility was observed predominantly among the mannitol group (images 7 and 8).

Most of the quadrants among the mannitol group showed excellent mucosal fold visibility (62/75 quadrants with excellent mucosal fold visibility), predominantly in the right lower quadrant (25/62 quadrants). Whereas only 13 out of 75 quadrants had excellent mucosal fold visibility in the iodine group (Table -6).

Images 7 and 8: 7. Excellent mucosal fold visibility and homogeneity of luminal contents in the mannitol group and 8. Satisfactory mucosal fold visibility, excellent distended uniformity and homogeneity of luminal contents in iodine Group

Homogeneity of luminal contents:

Excellent homogeneity of luminal contents noted in all the quadrants among the mannitol group (87/143) and are seen to be significantly greater in number compared to the iodine group (56/143)(Table 7: images 7 and 8). Statistically significant greater number of cases with poor homogeneity amongst iodine group and excellent overall homogeneity among mannitol group noted (Table 8).

Computed Tomography findings (Table 9)

It has been observed that in the mannitol group, 8 patients were diagnosed with inflammatory bowel disease followed by 4 colonic diverticulitis and 1 colorectal carcinoma. Likewise, 5 cases of inflammatory bowel disease followed by 2 each colonic diverticulitis and colorectal carcinoma was diagnosed among the iodine group.

Palatability and tolerability - Tables 10 to 13

It has been noted that 17 patients had good palatability, and 37 had reasonable palatability for diluted mannitol. Of the 54 patients in the iodine group, 47 had reasonable palatability, 6 had good palatability, and only one patient had bad palatability with statistically significant (p=0.024) difference in palatability among mannitol and iodine groups.  In the mannitol group, only 3 patients had mild nausea, while in the iodine group, 13 patients had mild nausea, and 3 had severe nausea, which was statistically significant. Vomiting is observed significantly in the iodine group (14 patients). Patients who received mannitol had experienced mild diarrhea (12%), more than the iodine group subjects

Small intestine imaging is complicated because of its long length, caliber, convoluted, and densely packed loops. With the introduction of MDCT, there has been a significant improvement in contrast and spatial resolution which aids in the visualization of bowel loops. CT imaging has become a widespread investigation for diagnosing small bowel pathologies because it aids in disease localization and extent. There has been a steady shift toward utilizing low attenuation contrast agents rather than positive agents for abdominopelvic imaging in the recent years.

In this study, the mean of maximum distension was higher in all quadrants in the mannitol group. The overall mean dimension was also higher in the mannitol-water group (21.7±2.25) than the iodine-water group (18.23±2.35).The fold visibility in the small bowel and bowel uniformity was better with the mannitol group in all quadrants, especially in the right lower quadrant. Better homogeneity is also crucial as it leads to better mucosal and wall delineation. The homogeneity in the small intestine was also better in the mannitol-water group than in the iodine-water group. Distension of the colon was also more in the mannitol-water group than the iodine-water group, which facilitates the evaluation of pathologies like Inflammatory bowel disease. Thus, mannitol was a better contrast agent in bowel distension in this study.The mucosal enhancement patterns were obscured due to their high luminal attenuation character, thus causing artifacts, particularly in the distal ileum, which is one of the primary sites of small bowel pathologies.

Similar findings were noted in a study by K Prakashni et al ³¹conducted a study on 300 patients and concluded that mannitol was betterendo luminal contrast for bowel distension than water and meglumine diatrizoate. In addition, the study also concluded that mannitol was betterendo luminal contrast for bowel distension uniformity, homogeneity, and fold visibility than water and meglumine diatrizoate. Berther R et al⁶alsofound that the mannitol group showed significantly better bowel distension, better qualitative results for uniformity of bowel distension, the luminal content, delineation of the bowel wall to the lumen and the mesentery, with reduced artifacts resulting in significantly better overall image quality than meglumine ioxitalamate. In a comparative study by WangYRetal³in 2015 water, milk, diluted lactulose and isotonic mannitol were compared and found that the small bowel distension and visualization of intestinal structures were best with both diluted lactulose and mannitol. However, no significant difference (P > 0.05) was noted between the mannitol group and the lactulose group whereas it was statistically significant when compared these with other groups. Padmanabhan Elamparithi et al ³²concluded that mural enhancement, and fold visibility were excellent with the mannitol group compared to other groups and similarly, the wall visibility was significantly better in the mannitol group thanVoLumen group in a study by Wong J et al². The findings in this study were concordant with the other mentioned studies with respect to both quantitative and qualitative parameters.

Palatability and tolerability were good in the mannitol group, and mild diarrhea was reported in 12.9% of the cases in the mannitol similar to the reported observations in the studies by K Prakashni et al³¹, Padmanabhan Elamparithi et al ³², DeepakSinglaetal³⁴. No severe side effects were noted with mannitol as oral contrast agents similar to a study by Nikhil Vikram et al³⁵ and considered the taste of mannitol as acceptable with no discomfort except for few patients who reported mild frequency of watery stools after taking mannitol.

An ideal contrast agent should be low/iso attenuating luminal contrast which can provide adequate bowel distension and mural detail. Oral diluted mannitol performs better than diluted iodine as an oral contrast agent for evaluating small and large bowel loops in terms of distension, mucosa fold / wall visibility and bowel luminal content homogeneity (quantitatively and qualitatively). The diluted mannitol was also better in taste, better tolerated, and had fewer mild side effects.

1. Garrett PR, Meshkov SL, Perlmutter GS. Oral contrast agents in CT of the abdomen. Radiology. 1984 Nov;153(2):545-6.
2. Wang YR, Yu XL, Peng ZY. Evaluation of different small bowel contrast agents by multi- detector row CT. International journal of clinical and experimental medicine. 2015; 8(9):16175.
3. Wong J, Moore H, Roger M, McKee C. CT enterography: mannitol versus VoLumen. Journal of medical imaging and radiation oncology. 2016 Oct;60(5):593-8.
4. Horton KM, Fishman EK. The current status of multidetector-row CT and three- dimensional imaging of the small bowel. Radiologic clinics of North America. 2003 Mar 1;41(2):199-212.
5. Nolan DJ. Enteroclysis of non-neoplastic disorders of the small intestine. European radiology. 2000 Jan; 10(2):342-53.
6. Berther R, Patak MA, Eckhardt B, Erturk SM, Zollikofer CL. Comparison of neutral oral contrast versus positive oral contrast medium in abdominal multidetector CT. European radiology. 2008 Sep;18(9):1902-9.
7. Macari M, Megibow AJ, Balthazar EJ. A pattern approach to the abnormal small bowel: observations at MDCT and CT enterography. American Journal of Roentgenology. 2007 May;188(5):1344-55.
8. Young BM, Fletcher JG, Booya F, Paulsen S, Fidler J, Johnson CD, Huprich J, Barlow J, TroutA.Head-to-headcomparisonoforalcontrastagentsforcross-sectionalenterography: smallboweldistention,timing,andsideeffects.Journalofcomputer-assistedtomography. 2008 Jan 1;32(1):32-8.
9. Buttigieg EL, Grima KB, Cortis K, Soler SG, Zarb F. An evaluation of the use of oral contrast media in abdominopelvic CT. European radiology. 2014 Nov;24(11):2936-44.
10. Recentadvancesinintestinalimaging.TheIndianjournalofradiology&imaging. 2011 Jul;21(3):170.
11. Zhang LH, Zhang SZ, Hu HJ, Gao M, Zhang M, Cao Q, Zhang QW. Multi-detector CT enterographywithiso-osmoticmannitolasoralcontrastfordetectingsmallboweldisease. World Journal of Gastroenterology: WJG. 2005 Apr 21;11(15):2324.
12. HongSS,KimAY,ByunJH,Won HJ, KimPN,LeeMG, HaHK.MDCT ofsmall-bowel disease: value of 3D imaging. American Journal of Roentgenology. 2006 Nov;187(5):1212-21.
13. Megibow AJ, Babb JS, Hecht EM, Cho JJ, Houston C, Boruch MM, Williams AB. Evaluation of bowel distention and bowel wall appearance by using neutral oral contrast agent for multi-detector row CT. Radiology. 2006 Jan;238(1):87-95.
14. Rupa SA, Al Azad S, Chakraborty NR. Milk-An Effective Low-Attenuation Computed Tomography Oral Contrast Medium. Journal of Enam Medical College. 2013 Aug 7;3(2):71-6.
15. Evrimler S, Algin O. MR enterography with oral contrast agent composed of methylcellulose,low-dosebariumsulfate,sorbitol,andlactulose:assessmentofdiagnostic performance, reliability,imagequality,andpatienttolerance.Clinicalimaging.2016May 1;40(3):523-30.
16. Gulati K, Shah ZK, Sainani N, Uppot R, Sahani DV. Gastrointestinal tract labeling for MDCT of abdomen: Comparison of low density barium and low density barium in combination with water. European radiology. 2008 May;18(5):868-73.
17. KooCW,Shah-PatelLR,BaerJW,FragerDH.Cost-effectivenessandpatienttoleranceof low-attenuation oral contrast material: milk versus VoLumen. American Journal of Roentgenology. 2008 May;190(5):1307-13.
18. MinordiLM,Vecchioli A,MirkP,BonomoL.CTenterographywithpolyethyleneglycol solutionvsCTenteroclysisinsmallboweldisease.TheBritishjournalof radiology.2011 Feb;84(998):112-9.
19. Lee CH, Haaland B, Earnest A, Tan CH. Use of positive oral contrast agents in abdominopelvic computed tomography for blunt abdominal injury: meta-analysis and systematic review. European radiology. 2013 Sep;23(9):2513-21.
20. WinterTC,AgerJD,NghiemHV,HillRS,HarrisonSD,FreenyPC.Uppergastrointestinal tract and abdomen: water as an orally administered contrast agent for helical CT. Radiology. 1996 Nov;201(2):365-70.
21. Winter3rdTC,FreenyPC,NghiemHV.Extrapancreaticgastrinomalocalization:valueof arterial-phase helical CT with water as an oral contrast agent. AJR. American journal of roentgenology. 1996 Jan;166(1):51-2.
22. Baert AL, Roex L, Marchal G, Hermans P, Dewilde D, Wilms G. Computed tomography of the stomach with water as an oral contrast agent: technique and preliminary results. Journal of computer assisted tomography. 1989 Jul 1;13(4):633-6.
23. Gossios KJ, Tsianos EV, Demou LL, Tatsis CK, Papakostas VP, Masalas CN, Merkouropoulos MC, Kontogiannis DS. Use of water or air as oral contrast media for computed tomographic study of the gastric wall: comparison of the two techniques. Gastrointestinal radiology. 1991 Dec;16(1):293-7.
24. Hori S, Tsuda K, Murayama S, Matsushita M, Yukawa K, Kozuka T. CT of gastric carcinoma: preliminary results with a new scanning technique. Radiographics. 1992 Mar;12(2):257-68.
25. Turetschek K, Schober E, Wunderbaldinger P, Bernhard C, Schima W, Puespoek A, Vogelsang H, Moeschl P, Mostbeck G. Findings at Helical CT–Enteroclysis in Symptomatic Patients With Crohn Disease: Correlation With Endoscopic and Surgical Findings. Journal of computer assisted tomography. 2002 Jul 1;26(4):488-92.
26. Wold PB, Fletcher JG, Johnson CD, Sandborn WJ. Assessment of small bowel Crohn disease: noninvasive peroral CT enterography compared with other imaging methods and endoscopy—feasibility study. Radiology. 2003 Oct;229(1):275-81.
27. Reittner P, Goritschnig T, Petritsch W, Doerfler O, Preidler KW, Hinterleitner T, Szolar DH. Multiplanar spiral CT enterography in patients with Crohn's disease using a negative oral contrast material: initial results of a noninvasive imaging approach. European radiology. 2002 Sep;12(9):2253-7.
28. Ramsay DW, Markham DH, Morgan B, Rodgers PM, Liddicoat AJ. The use of dilute Calogen®asafatdensityoralcontrastmediuminupperabdominalcomputedtomography, compared with the use of water and positive oral contrast media. Clinical radiology. 2001 Aug 1;56(8):670-3.
29. Lee SB, Kim SH, Son JH, Baik JY. Evaluation of bowel distension and bowel wall visualizationaccordingtopatientpositionsduringadministrationoforalcontrastmediafor CT enterography. The British journal of radiology. 2017 Oct;90(1080):20170352.
30. Kung CH, Wang HJ, Leung TK, Lin YH, Chen YY, Lee CM. Depiction of bowel wall visualization and dilation in abdominopelvic MDCT: comparison of high-attenuation contrast medium, water and whole milk. Journal of Experimental & Clinical Medicine. 2010 Aug 1;2(4):186-91.
31. Prakashini K, Kakkar C, Sambhaji C, Shetty CM, Rao VR. Quantitative and qualitative bowel analysis using mannitol, water and iodine-based endoluminal contrast agent on 64- row detector CT. The Indian journal of radiology & imaging. 2013 Oct;23(4):373.
32. ElamparidhiP,SivaranjanieS,KumarRR,SibhithranR,KumarAA.Comparisonofwater, mannitol and positive oral contrast for evaluation of bowel by computed tomography. International Journal of Anatomy, Radiology and Surgery. 2017;6(4).
33. Wong J, Roger M, Moore H. Performance of two neutral oral contrast agents in CT enterography. Journal of medical imaging and radiation oncology. 2015 Feb;59(1):34-8.
34. SinglaD,ChandakS,MalhotraA,AgarwalA,RamanT,ChaudharyM.CTEnterography Using Four Different Endoluminal Contrast Agents: A Comparative Study. Journal of Gastrointestinal and Abdominal Radiology. 2021 Jun 11.
35. Vikram N, Rahalkar AM, Rahalkar M, Halkude A, Rana P, Khopade P. Comparison of Mannitol and Meglumine Diatrizoate for Stomach and Small Bowel Wall Study by Computed Tomography, a Prospective Study. Radiology. 2019;4(3):C162-7.
36. SiddiquiMA,ZIAULISLAMHA,SAQIBHA,FIRDOUSA,AMINM,KHANComparison of Mannitol, Water and Positive Oral Contrast for Evaluation of Bowel Pathology by Computed Tomography. Pakistan Journal of Medical and Health Sciences. 2021;15(4):848-50.
37. Zheng MQ, Zeng QS, Yu YQ, Ji R, Li YY, Zhang MM, Sun YN, Li LX, Zuo XL, Yang XY,LiYQ.Evaluation of the performance of two neutral oral contrast agents in computed tomography enterography: A randomized controlled trial. Journal of digestive diseases. 2020 Feb; 21(2):112-9.
38. YanG,WangH,Chen W,LiuW. Clinical application of multislice CT enterography with hypertonic mannitol saline as oral contrast. Journal of Diagnostic Imaging and Interventional Radiology. 2011;20(5):361-6.