Computed tomography of Crohn’s disease: The role of three dimensional technique

Saudi Arabia consensus guidance for the diagnosis and management of adults with inflammatory bowel disease

Optimal management of inflammatory bowel disease (IBD) relies on a clear understanding and tailoring evidence-based interventions by clinicians in partnership with patients. This article provides concise guidelines for the management of IBD in adults, based on the most up-to-date information at the time of writing and will be regularly updated. These guidelines were developed by the Saudi Ministry of Health in collaboration with the Saudi Gastroenterology Association and the Saudi Society of Clinical Pharmacy. After an extensive literature review, 78 evidence-and expert opinion-based recommendations for diagnosing and treating ulcerative colitis and Crohn's disease in adults were proposed and further refined by a voting process. The consensus guidelines include the finally agreed on statements with their level of evidence covering different aspects of IBD diagnosis and treatment.

Multidetector computed tomography: a corner stone imaging modality in evaluation of acute small bowel diseases

Background

The diagnosis of acute small bowel diseases is one of the challenging issues that confronted by the radiologists so accurate diagnosis is essential to determine the appropriate way of management. CT has become the preferred imaging tool to evaluate acute small bowel diseases. Our study aimed to assess the role of MDCT in evaluation of acute abdomen secondary to small bowel origin by identification and differentiation between different acute small bowel pathologies.

Results

Thirty-eight patients presented with acute abdomen of small bowel origin from June 2019 to September 2019. The mean age of incidence was 48 ± 19 years ranged from 4 to 88 years. Males represented by 23 patients (60.5%). Acute exacerbation of inflammatory bowel diseases (Crohn’s disease) represented by (34.2%), small bowel obstruction (31.6%), ischemic bowel diseases (21.1%), small bowel perforation (10.5%) and infectious (TB enteritis) small bowel disease (2.6%). MDCT had an overall high sensitivity (97.3%) in assessment of acute small bowel diseases in correlation with post-operative data and follow-up response to management.

Conclusions

MDCT is a reliable diagnostic imaging tool for assessment of patients with acute abdomen secondary to small bowel origin with high-efficiency in differentiation between different pathological entities that causing acute abdomen.

Dual energy CT in acute appendicitis: value of low mono-energy

OBJECTIVES

To assess the potential role of low monoenergetic images in the evaluation of acute appendicitis.

METHODS

A retrospective study of 42 patients with pathology proven acute appendicitis underwent contrast-enhanced-CT conducted on a single-source-DECT before surgery. Attenuation, SNR, and CNR were calculated on both monoenergetic and conventional images and compared to 24 abdominal CT-scans with normal appendix. Representative conventional and monoenergetic images were randomized and presented side-by-side to three abdominal radiologists to determine preferred images for detecting inflammation. Additionally, six individual acute inflammatory characteristics were graded on a 1-5 scale to determine factors contributing to differences between conventional and monoenergetic images by 2 abdominal radiologists. Paired t-tests, Wilcoxon and McNemar tests, and intra-observer error statistics were performed.

RESULTS

For the inflamed appendixes monoenergetic images had overall increased attenuation (average ratio 1.7; P < 0.05), signal-to-noise-ratio (6.7 ± 3.1 vs 4.2 ± 1.6; P < 0.001) and contrast-to-noise-ratio (12.1 ± 3 vs 9 ± 2.1; P < 0.001). Moreover, this increase was not found in normal appendixes (P < 0.001 vs p = 0.28-0.44). Subjectively, radiologists showed significant preferences towards monoenergetic images (P < 0.001), with inter-reader agreement of 0.84. Two parameters, diffuse bowel wall and mucosal enhancement, received significantly higher scores on monoenergetic images (average 4.3 vs. 3.0; P < 0.001 and 2.8 vs. 2.3 P < 0.03 respectively, with interobserver agreements of 62% and 52%).

CONCLUSION

Increased bowel wall conspicuity from enhanced attenuation, SNR, and CNR on low monenergetic CT images results in a significant preference by radiologists for these images when assessing acute inflamed appendixes. Thus, close inspection of low monoenergetic images may improve the visualization of acute inflammatory bowel processes.

Crohn's disease at radiological imaging: focus on techniques and intestinal tract

Over recent years, inflammatory bowel diseases have become an issue of increased attention in daily clinical practice, due to both a rising incidence and improved imaging capability in detection. In particular, the diagnosis of Crohn's disease is based on clinical picture, laboratory tests and colonoscopy with biopsy. However, colonoscopic evaluation is limited to the mucosal layer. Thus, imaging modalities play a pivotal role in enriching the clinical picture, delivering information on intestinal and extraintestinal involvement. All the imaging modalities can be employed in evaluation of Crohn's disease patients, each of them with specific strengths as well as limitations. In this wide selection, the choice of a proper diagnostic framework can be challenging for the clinician. Therefore, the aim of this work is to offer an overview of the different imaging techniques, with brief technical details and diagnostic potential related to each intestinal tract.

Gastrointestinal Applications of Iodine Quantification Using Dual-Energy CT: A Systematic Review

Dual-energy computed tomography (DECT) can estimate tissue vascularity and perfusion via iodine quantification. The aim of this systematic review was to outline current and emerging clinical applications of iodine quantification within the gastrointestinal tract using DECT. The search was conducted with three databases: EMBASE, Pubmed and The Cochrane Library. This identified 449 studies after duplicate removal. From a total of 570 selected studies, 30 studies were enrolled for the systematic review. The studies were categorized into four main topics: gastric tumors (12 studies), colorectal tumors (8 studies), Crohn’s disease (4 studies) and miscellaneous applications (6 studies). Findings included a significant difference in iodine concentration (IC) measurements in perigastric fat between T1–3 vs. T4 stage gastric cancer, poorly and well differentiated gastric and colorectal cancer, responders vs. non-responders following chemo- or chemoradiotherapy treatment among cancer patients, and a positive correlation between IC and Crohn’s disease activity. In conclusion, iodine quantification with DECT may be used preoperatively in cancer imaging as well as for monitoring treatment response. Future studies are warranted to evaluate the capabilities and limitations of DECT in splanchnic flow.

The Additional Diagnostic Value of the Three-dimensional Volume Rendering Imaging in Routine Radiology Practice

Three-dimensional volume rendering (3DVR) is useful in a wide variety of medical-imaging applications. The increasingly advanced capabilities of CT and MRI to acquire volumetric data sets with isotropic voxels have resulted in the increased use of the 3DVR techniques for clinical applications. The two most commonly used techniques are the maximum intensity projection (MIP) and, more recently, 3DVR. Several kinds of medical imaging data could be reconstructed for 3D display, including CT, MRI, and ultrasonography (US). In particular, the 3D CT imaging has been developed, improved, and widely used of late. Understanding the mechanisms of 3DVR is essential for the accurate evaluation of the resulting images. Although further research is required to detect the efficiency of 3DVR in radiological applications, with wider availability and improved diagnostic performance, 3DVR is likely to enjoy widespread acceptance in the radiology practice going forward.

Value of dual-energy CT enterography in the analysis of pathological bowel segments in patients with Crohn's disease

OBJECTIVE

To analyze whether there are significant differences in the objective quantitative parameters obtained in the postprocessing of dual-energy CT enterography studies between bowel segments with radiologic signs of Crohn's disease and radiologically normal segments.

MATERIAL AND METHODS

This retrospective study analyzed 33 patients (16 men and 17 women; mean age 54 years) with known Crohn's disease who underwent CT enterography on a dual-energy scanner with oral sorbitol and intravenous contrast material in the portal phase. Images obtained with dual energy were postprocessed to obtain color maps (iodine maps). For each patient, regions of interest were traced on these color maps and the density of iodine (mg/ml) and the fat fraction (%) were calculated for the wall of a pathologic bowel segment with radiologic signs of Crohn's disease and for the wall of a healthy bowel segment; the differences in these parameters between the two segments were analyzed.

RESULTS

The density of iodine was lower in the radiologically normal segments than in the pathologic segments [1.8 ± 0.4mg/ml vs. 3.7 ± 0.9mg/ml; p<0.05]. The fat fraction was higher in the radiologically normal segments than in the pathologic segments [32.42% ± 6.5 vs. 22.23% ± 9.4; p<0.05].

CONCLUSION

There are significant differences in the iodine density and fat fraction between bowel segments with radiologic signs of Crohn's disease and radiologically normal segments.

The effect of without using anisodamine during CT enterography on image quality, diagnostic performance and latent side effects

OBJECTIVE

To examine whether no anisodamine injection before CTE was feasible without impairing image quality and diagnostic performance.

MATERIALS

The change of mural thickness and luminal diameter were compared between using and no using anisodamine. The diagnostic performance of small-bowel disease was analyzed and compared.

RESULTS

No motion artifact was detected in two groups. There was no significant difference regarding the change of luminal diameter and mural thickness (all P>0.05). The diagnostic accuracy of small-bowel disease was no significant difference (P=0.63).

CONCLUSION

Lack of anisodamine injection before CTE did not impair image quality and diagnostic performance compared with CTEs performed with anisodamine injection.

Acute Bowel Computed Tomography

Acute abdominal pain is a common presenting complaint in the emergency department. Increasingly, computed tomography is utilized for evaluating these patients. Radiologists are therefore expected to be familiar with the pertinent clinical and radiologic information related to acute bowel pathology. This primer will review the need-to-know and latest updates related to computed tomography evaluation of acute bowel pathology.

Split-Bolus Injection Producing Simultaneous Late Arterial and Portal Venous Phases in CT Enterography: Preliminary Results

OBJECTIVE

The purpose of this article is to evaluate the image quality and added value of split-bolus contrast agent injection combining late arterial and portal venous phases compared with single-bolus contrast agent injection late arterial phase CT enterography.

MATERIALS AND METHODS

Consecutive patients who underwent CT enterography before and after implementation of a single-bolus CT enterography protocol were included. Attenuation and contrast-to-noise ratio (CNR) were assessed by ROI measurements of the bowel wall and arterial and venous structures. Subjective enhancement of the bowel wall (1, arterial; 2, mucosal; 3, transmural; 4, transmural with mucosal hyperenhancement) and bowel abnormalities were assessed by two independent readers. MR enterography examinations, endoscopy reports, and surgery reports within 30 days after CT enterography were used to produce a composite outcome.

RESULTS

Sixty-six patients were included in our study: 33 (mean [± SD] age, 46.0 ± 19.8 years) who underwent split-bolus CT enterography and 33 (mean age, 49.9 ± 19.0 years) who underwent single-bolus CT enterography. Bowel wall attenuation and CNR were higher for split-bolus CT enterography than for single-bolus CT enterography at 120 kVp (enhancement, 98.7 ± 23.1 HU vs 85.1 ± 23.3 HU; CNR, 6.4 ± 2.5 vs 4.4 ± 2.3; p < 0.01). Subjective ratings of bowel wall enhancement were higher with the split-bolus CT enterography than the single-bolus CT enterography (2.6 ± 0.8 vs 2.3 ± 0.6; p < 0.001). Split-bolus CT enterography led to a higher detection rate of mucosal hyperenhancement than did single-bolus CT enterography in patients with active inflammatory bowel disease (100.0% [7/7; 95% CI, 59.0-100.0%] vs 33.3% [2/6; 95% CI, 4.3-77.7%]; p = 0.02), whereas both protocols had a specificity of 100.0% (9/9).

CONCLUSION

Split-bolus CT enterography led to improved CNR (47%) compared with single-bolus CT enterography and significantly increased the detection rate of mucosal hyperenhancement in patients with active inflammatory bowel disease.

Multimodality imaging of diseases of the duodenum

The duodenum is a unique segment of intestine, occupying both intra and extra-peritoneal locations. There is a wide spectrum of abnormalities of the duodenum that range from congenital anomalies to traumatic, inflammatory, and neoplastic entities. The duodenum may be overlooked on cross-sectional imaging due to its location and small size. Duodenal pathologies may, therefore, be missed or wrongly diagnosed. Knowledge about duodenal pathologies and optimal imaging techniques can increase diagnostic yield and permit optimal patient management. Conventionally, the duodenum was evaluated with upper GI studies on fluoroscopy; however, endoluminal evaluation is better performed with endoscopy. Additionally, a broad array of cross-sectional imaging modalities permits comprehensive assessment of the duodenum and surrounding viscera. While endoscopic sonography is increasingly used to locally stage duodenal malignancies, MDCT remains the primary modality widely used in the detection and characterization of duodenal abnormalities. MRI is used as a "problem solving" modality in select conditions. We present a comprehensive review of duodenal abnormalities with an emphasis on accurate diagnosis and management.

Evolution of imaging in rectal cancer: multimodality imaging with MDCT, MRI, and PET

Magnetic resonance imaging (MRI), multidetector computed tomography (MDCT), and positron emission tomography (PET) are complementary imaging modalities in the preoperative staging of patients with rectal cancer, and each offers their own individual strengths and weaknesses. MRI is the best available radiologic modality for the local staging of rectal cancers, and can play an important role in accurately distinguishing which patients should receive preoperative chemoradiation prior to total mesorectal excision. Alternatively, both MDCT and PET are considered primary modalities when performing preoperative distant staging, but are limited in their ability to locally stage rectal malignancies. This review details the role of each of these three modalities in rectal cancer staging, and how the three imaging modalities can be used in conjunction.