Colitis: use of CT findings in differential diagnosis

Role of multidetector computed tomography in patients with acute infectious colitis

BACKGROUND

The role of multidetector computed tomography (MDCT) in patients with acute infectious colitis is still unclear.

AIM

To examine the usefulness of MDCT in distinguishing the etiology of acute infectious colitis.

METHODS

Overall, 244 patients who met the criteria for acute infectious colitis and visited the Hospital from February 2015 to 2018 were retrospectively enrolled and divided into two groups (bacterial: 204, viral: 40) according to causes of acute colitis, based on stool PCR. Eleven MDCT parameters, including wall thickening, submucosal edema, mucosal enhancement, serosa involvement, empty colon sign, small bowel involvement, comb sign, continuous distribution, accordion sign, mucosal thickening, and lymph node enlargement, were constructed in a blinded fashion.

RESULTS

MDCT parameters of wall thickening (OR: 13.60; 95%CI: 5.80–31.88; P < 0.001), submucosal edema (OR: 36.08; 95%CI: 13.54–96.13; P < 0.001), mucosal enhancement (OR: 22.55; 95%CI: 9.28–54.81; P < 0.001), serosal involvement (OR: 14.50; 95%CI: 3.33–63.23; P < 0.001), empty colon sign (OR: 6.68; 95%CI: 2.44–18.32; P < 0.001), continuous distribution (OR: 24.09; 95%CI: 9.38–61.90; P < 0.001), accordion sign (OR: 9.02; 95%CI: 1.12–72.35; P = 0.038), mucosal thickening (OR: 46.41; 95%CI: 10.38–207.51; P < 0.001), and lymph node enlargement (OR: 4.39; 95%CI: 1.22–15.72; P = 0.023) were significantly associated with bacterial colitis. At least one positive finding in four CT outcomes (submucosal edema, mucosal enhancement, continuous distribution, mucosal thickening) in summer showed a high probability of bacterial colitis (sensitivity, 41.67; specificity, 92.50; OR: 24.95).

CONCLUSION

MDCT provides many clues that can be useful in suggesting a specific etiology of acute infectious colitis.

[Incidental and "leave me alone" findings of the GI tract-part 2 : Intestinal wall and mesentery]

Due to the widespread use of computed tomography (CT) and magnetic resonance imaging (MRI) asymptomatic incidental findings of the gastrointestinal (GI) tract are increasingly being recognized. Incidental findings are frequently not part of the primary inquiry from referring physicians but it is obligatory to make a diagnosis and to stipulate the need for further clarification. A multitude of incidental findings in the intestinal lumen, in the intestinal wall and in the adjacent mesentery or subperitoneal space are shown in CT and MRI of the GI tract. The last part of the two-part review addresses the gastrointestinal incidental findings in the intestinal wall and the adjacent sections. Extramural incidental findings occur as mesenteric inflammation, tumors and cysts. Many of the findings can be classified as benign and as "leave me alone lesions" do not necessitate any further clarification but in contrast others need a definitive clarification. The most important incidental findings in the GI tract are systematically classified, illustrated and evaluated with respect to the clinical relevance, depending on the localization (e.g. stomach, small and large intestines).

Detection of intramural fat accumulation by 3D-Dixon-Caipirinha-Vibe and the contribution of this technique to the determination of the chronicity of Chron's disease

OBJECTIVES

In this study; we aimed to evaluate the efficacy of the 3D-Dixon-Caipirinha-Vibe fat images in detecting intramural fat accumulation (IFA) and contributions of 3D-Dixon-Caipirinha-Vibe in the management of patients with Chron's disease.

METHODS

Eighty-five patients who had a 3-tesla MR enterography (MRE) with the 3D-Dixon-Caipirinha-Vibe technique were included. Wall thickness, ADC-value, intramural edema, presence/extension of IFA, and contrast-material enhancement of the affected segments were examined. Findings of MRE were compared statistically with clinical, laboratory, endoscopy, and pathological exams.

RESULTS

The presence of IFA was more common in patients with chronic active and chronic inflammation than only active inflammation and normal cases. Patients with IFA had a longer disease duration than patients without IFA. IFA-containing segment lengths of patients with chronic active inflammation and chronic inflammation were found to be longer than those with active inflammation. It was found that patients whose pathology results were reported as active inflammation contained less IFA than patients with chronic inflammation.

CONCLUSIONS

The presence of IFA is strongly related to chronicity. 3D-Dixon-Caipirinha-Vibe is a fast, easy, and useful method for detecting IFA and evaluating Chron's disease.

Spectrum and Relevance of Incidental Bowel Findings on Computed Tomography

A wide spectrum of incidental bowel findings can be seen on CT, including but not limited to, pneumatosis intestinalis, diverticular disease, non-obstructive bowel dilatation, transient small bowel intussusception, and submucosal fat. Radiologists should be aware that such findings are almost always benign and of little clinical significance in the absence of associated symptoms. Conversely, vigilance must be maintained when evaluating the bowel, because malignant neoplasms occasionally come to clinical attention as incidental imaging findings. When suspicious incidental bowel wall thickening is detected, the radiologist can alert the clinical team to the finding prior to the patient becoming symptomatic, potentially leading to definitive management at an early, more curable stage.

Multi-detector computed tomography (MDCT)-based severity score as a prognostic tool in patients with suspected immune checkpoint inhibitor therapy associated colitis

OBJECTIVE

This study aimed to assess MDCT as a diagnostic and prognostic tool in patients with suspected immune checkpoint inhibitor (ICI)-related colitis.

MATERIALS AND METHODS

This retrospective cohort study included patients receiving ICIs at three hospitals between 2015 and 2019 who underwent both abdominopelvic MDCT and endoscopic biopsy to workup suspected ICI-related colitis. Two radiologists independently reviewed MDCT images for signs of colitis based on pre-defined features. Diagnostic performance of MDCT was calculated and categorical variables between treatment subgroups were compared. Logistic regression was used to develop proposed MDCT criteria for diagnosis and MDCT severity score based on a combination of MDCT features of colitis to predict the patient outcomes in ICI-related colitis.

RESULTS

A total of 118 MDCT scans from 108 patients were evaluated for suspected colitis, with 72 confirmed ICI-related colitis cases. Sensitivity, specificity, PPV, and NPV of MDCT for diagnosis of ICI-related colitis was 81% (58/72), 52 % (24/46), 73% (58/80), and 63% (24/38), respectively. Small bowel involvement was visualized in 25% of cases with ICI-related colitis (18/72). In melanoma patients presenting with diarrhea grade ≥ 2 (n = 40), MDCT had the best diagnostic performance for ICI-related colitis (specificity = 80% [8/10], PPV = 92% [23/25]). MDCT severity scores predicted intravenous steroid use (OR 10.3, p = 0.004), length of stay > 7 days (OR 9.0, p < 0.001), and endoscopic mucosal ulceration (OR 4.7, p = 0.02).

CONCLUSION

MDCT is a useful diagnostic and prognostic tool for evaluating patients with immune checkpoint inhibitor-related colitis. An MDCT-based severity score enables assessment of disease severity and predicts outcome.

KEY POINTS

• MDCT is useful for the diagnosis of colitis in patients receiving immune checkpoint inhibitor (ICI) therapy, and an MDCT-based severity score allows for prognostication of patient outcomes. • MDCT yielded moderate sensitivity (81%) for diagnosis of ICI-related colitis but limited specificity (52%). However, in symptomatic melanoma patients (grade 2-4 diarrhea) with a high pretest probability, MDCT proved useful for diagnosis with a high PPV (92%). • For ICI-related colitis, our proposed MDCT severity score has prognostic value in predicting intravenous steroid use, prolonged length of stay during inpatient admission (> 7 days), and endoscopic mucosal ulceration.

Ulcerative Colitis: Making the Diagnosis

Ulcerative colitis is an inflammatory condition of the colon. The diagnosis of ulcerative colitis is based on clinical presentation, endoscopic evaluation, and histologic parameters in the absence of demonstrable alternate etiology. The differential diagnosis remains broad, and infection in particular must be considered and excluded. Although laboratory and radiographic findings can aid in the diagnosis of ulcerative colitis, endoscopy remains the gold standard for diagnosis. A correct diagnosis and disease staging are imperative because these factors affect treatment options and prognosis.

Characteristics and outcomes of acute colitis diagnosed on cross-sectional imaging presenting via the emergency department in an Irish academic medical centre

BACKGROUND AND AIMS

A significant proportion of patients presenting to the Emergency Department with gastrointestinal symptoms that result in cross-sectional imaging receive a radiological diagnosis of colitis. We aimed to review the characteristics, outcomes, and final diagnoses of new emergency department presentations with colitis diagnosed on cross-sectional imaging.

METHODS

A radiology database was interrogated to identify patients admitted from the Emergency Department of St James's Hospital whose cross-sectional imaging demonstrated colitis. Baseline demographic data, information on inpatient investigations, final diagnoses, and outcomes were recorded. Adverse outcomes were defined as a requirement for surgery, intensive care unit (ICU) stay, or mortality RESULTS: A total of 118 patients, 67% female, were identified with a median age of 64 years (range 16.9-101.2). Median (range) admission duration was 10 days (1-241). Final colitis diagnoses were infectious (28%), undefined (27%), reactive (18%), inflammatory bowel disease (11%), ischaemic (9%), chemotherapy-associated (3%), diverticular (3%), and medication-associated (1%). Colonic perforation, colectomy, and mortality occurred in 1%, 5%, and 13% of the cohort respectively. On univariate analysis, low haemoglobin, low albumin, high lactate, and male gender were associated with adverse outcomes with the following odds ratios (OR) and 95% confidence intervals (95%CI) were low haemoglobin 1.49 [1.15-1.92] P = 0.002, low albumin 1.16 [1.07-1.25] P = 0.0002, lactate 1.65 [1.13-2.42] P = 0.009, and male gender 3.09 [1.23-7.77] P = 0.019. On multivariate analysis, male gender was associated with adverse outcomes.

CONCLUSION

Patients presenting to the Emergency Department with a colitis, requiring an abdominal CT are a heterogenous group with a proportion having concomitant intra-abdominal pathology resulting in critical illness. Hence their is a significant morbidity and mortality observed in this cohort which should not be extrapolated to a general population of patients presenting with colitis. In this cohort of patients, anaemia, hypoalbuminaemia, and elevated lactate in patients presenting to the ED with acute colitis are significantly associated with adverse outcomes. Early recognition of these prognostic factors may identify the cohort of patients who are best managed in a high-dependency setting.

Nonocclusive Ischemic Colitis: Analysis of Risk Factors for Severity

The purpose of this study was to identify risk factors predictive of severe nonocclussive ischemic colitis (IC) requiring operation or resulting in mortality. One hundred seventeen patients with nonocclussive IC were identified and divided into two groups: those with severe disease (n = 24) and those with disease that resolved with supportive care (n = 93). Univariate and multivariate logistic regression models were used. The splenic flexure was the most common involved segment (57.3%), whereas the right colon was involved in 17.9 per cent of patients. Multivariate logistic regression identified three independent risk factors for severe disease: leukocytosis greater than 15 3 109/L (odds ratio [OR], 5.7; confidence interval [CI], 1.5 to 21), hematocrit less than 35 per cent (OR, 4.5; CI, 1.1 to 17), and history of atrial fibrillation (OR, 15; CI, 1.3 to 190). Right-sided IC and chronic renal insufficiency did not affect severity. Special attention should be given to patients with the following risk factors for a severe course: atrial fibrillation, elevated white blood cell count, and anemia. These factors might enable earlier identification of patients who may benefit from early operation. Further prospective studies focusing on subgroups of IC (occlusive and nonocclusive) are required.

Radiologic Imaging of Bowel Infections

Although radiologic imaging of bowel infections is often a precursor to definitive diagnosis by endoscopy, biopsy, or stool cultures, imaging can provide critical information for diagnosis and management. Many infectious entities such as viral, bacterial, and parasitic infections can be discovered on imaging. Furthermore, imaging characterizes the extent of infection, involvement of specific bowel segments, and presence of complications in the abdomen. Utilizing a multimodality approach using ultrasound, computed tomography, and magnetic resonance imaging, we describe the spectrum of imaging findings that distinguish a number of infectious etiologies that affect the bowel, as well as differentiate from ischemic and inflammatory bowel processes.

Clostridium difficile colitis: CT findings and differential diagnosis

Clostridium difficile infection (CDI) is a severe and potentially deadly infectious colitis whose incidence is dramatically increasing in the last decades, with more virulent strains. CDI should be suspected in case of unexplained diarrhea and abdominal pain in patients with a recent history of antibiotic use and healthcare exposures; diagnosis is based on a combination of clinical and laboratory findings with demonstration of C. difficile toxins by stool test. The advantages of contrast-enhanced computed tomography (CECT) are the noninvasiveness and the ability to evaluate both the colonic wall and the adjacent soft tissues. Considerable overlap exists between the CECT findings of CDI and those of colitis of other origins, such as typhlitis, ischemic colitis, graft-versus-host disease, radiation colitis and inflammatory bowel diseases; however, some features may help distinguish between these conditions. This paper provides a comprehensive overview of the imaging features of Clostridium difficile colitis and its mimics, with a view to assist the radiologist in reaching the correct diagnosis.

Fulminant amoebic colitis in the era of computed tomography scan: A case report and review of the literature

Amoebic colitis, caused by ingestion of water or food contaminated with the protozoan Entamoeba histolytica, can progress to a fulminant colitis. Computed tomography (CT) findings reported in the literature on this type of colitis are sparse. We present a 59-year-old male patient with a one-week history of progressive abdominal pain, abdominal distension and associated watery and bloody diarrhoea. A CT scan revealed deep ulcerations with submucosal and intramural tracking of contrast. Colonoscopy and biopsy confirmed a diagnosis of Amoebic colitis. The patient required a laparotomy and demised. Deep ulcerations with submucosal and intramural tracking of contrast on CT are diagnostic of fulminant amoebic colitis. Although not demonstrated at CT in this case, discontinuous bowel necrosis, omental wrapping (seen at laparotomy in our case) and neovascularisation of the bowel wall may be other features to look out for.

Non-occlusive mesenteric ischaemia: CT findings, clinical outcomes and assessment of the diameter of the superior mesenteric artery

OBJECTIVE

Review of the experience of a tertiary care centre for almost 10 years in the CT diagnosis of non-occlusive mesenteric ischaemia (NOMI). Analysis of CT findings, correlation with clinical outcomes and evaluation of the usefulness of measuring the superior mesenteric artery (SMA) diameter for the diagnosis of NOMI.

METHODS

106 patients were diagnosed with NOMI in a biphasic CT examination from 2008 to 2017 in our hospital. Clinical outcomes and CT findings were reviewed. In 55 patients, the diameter of the SMA was compared with a previous CT scan where NOMI was not the diagnosis, and statistical analysis using paired t-test was performed.

RESULTS

81 patients (76%) had findings consistent with small bowel ischaemia and the ileum was the segment most commonly involved (47%). Lack of wall enhancement, pneumoperitoneum, pneumatosis intestinalis and portal venous gas were all considered signs of bowel necrosis and surgery was performed promptly. 70 patients had signs of vascular narrowing of the SMA branches and in the 55 cases with a previous CT scan, there were statistically significant differences regarding the SMA diameter with a mean reduction of the artery calibre and standard deviation of 1.93 ± 1.1 mm between the NOMI and non-NOMI scans (p < 0.001).

CONCLUSION

Acknowledgment of characteristic bowel necrosis CT findings is crucial for determining the therapeutic attitude and the use of previous CT scans to compare the SMA diameter may help the radiologist to achieve an early diagnosis of NOMI in an often critically ill patient population. Advances in knowledge: Diagnosis of NOMI can be difficult in cases of partial mural ischaemia, thus objective data (diameter of the SMA) should be useful for the radiologist to include NOMI as the first diagnostic option in the differential diagnosis.

Gastric Wall Fatty Infiltration in Patients Without Overt Gastrointestinal Disease

OBJECTIVE

The purpose of this study was to evaluate the frequency of gastric wall fatty infiltration in patients without overt gastrointestinal disease.

MATERIALS AND METHODS

A retrospective study included patients who underwent unenhanced MDCT for renal colic. Two radiologists reviewed all of the images and evaluated for the presence of gastric wall fatty infiltration. The following patient characteristics were also recorded: sex, age, body mass index, total and visceral fat area, and presence of colic or ileal fat halo sign, or hepatic steatosis. A t test and Fisher test were used to compare the results between patients with and patients without gastric wall fatty infiltration.

RESULTS

Gastric wall fatty infiltration was present in 25 of 120 (21%) patients in the study. Mean age, weight, body mass index, visceral and total fat areas, proportion of hepatic steatosis, number of men, and frequency of the presence of colic and ileal fat halo signs were significantly higher among patients with gastric wall fatty infiltration than in those without infiltration.

CONCLUSION

Gastric wall fatty infiltration was significantly more frequent in men older than 45 years and patients with a body mass index greater than 25. It may represent a normal finding, but its relation to other pathologic conditions related to obesity remains to be explored.

Evaluating the Patient with Right Lower Quadrant Pain

Right lower quadrant pain is one of the most common indications for imaging evaluation of the abdomen in the emergency department setting. This article reviews important imaging findings associated with acute appendicitis as well as major differential considerations including: mesenteric adenitis, Meckel diverticulum, neutropenic colitis, right-sided diverticulitis, epiploic appendagitis, omental infarction, and inflammatory bowel diseaseRight lower quadrant pain is one of the most common indications for imaging evaluation of the abdomen in the emergency department setting. This article reviews important imaging findings associated with acute appendicitis as well as major differential considerations including: mesenteric adenitis, Meckel diverticulum, neutropenic colitis, right-sided diverticulitis, epiploic appendagitis, omental infarction, and inflammatory bowel disease.

Differential Diagnosis of Colonic Strictures: Pictorial Review with Illustrations from Computed Tomography Colonography

Strictures of the colon can lead to significant morbidity requiring surgical management. The etiology of strictures is broad and generally categorized as benign, malignant, or pseudostrictures. Computed tomography (CT) is a crucial imaging modality in the assessment and characterization of colonic pathologies but colonoscopy remains the diagnostic gold standard. However, in the setting of incomplete colonoscopy due to strictures, the imaging features of CT will be relied on. This review will focus on the CT features of different colon pathologies leading to strictures and will be illustrated with images from 10 years of experience with CT colonography at our institutions from 2002-2012 (Hotel Dieu Hospital, Queen's University and Mount Sinai Hospital, University of Toronto).

Ischemic colitis: spectrum of CT findings, sites of involvement and severity

To summarize the frequency of findings on IV contrast, enhanced computer tomography (CT) in 335 patients with pathologically proven ischemic colitis (IC) determine the most frequent locations and patterns of involvement and establish the correlation of these findings with the severity of IC. 231 patients were excluded for not having a concomitant CT or for having underlying comorbidities. 104 cases were analyzed. Scans were evaluated for abnormal wall enhancement (AE), bowel wall thickening (BWT), bowel dilatation (DIL), mesenteric fat stranding (FS), venous engorgement (VE), pericolonic free fluid (FF), and pneumatosis (PN) and portomesenteric venous gas. Segmental versus pancolonic involvement was noted. Severity was determined by histopathology criteria. Data obtained are as follows: female to male incidence, 69 % (70) vs. 31 % (34); average age, 64.5; and positive CT, 102/104 (98.1 %). The most frequent findings include FS (88 %), BWT (88 %), and AE (82 %) regardless of severity of involvement. Statistically significant increased risk ratio and likelihood of severe ischemia for PN, DIL, and FF individually. BWT, DIL, FS, FF, VE, and PN together have a probability for severe IC of 91.8 %. A correlation between fewer findings and milder IC was found (R (2) = 0.6771). The most frequently involved segments: descending (64 %) and sigmoid colon (54 %). Splenic flexure (SF) was infrequently involved (n = 8, 7.84 %). Females had two times higher incidence of IC. The most frequent CT findings in IC are FS, BWT, and AE regardless of the severity. PN is suggestive of severe IC. Segmental involvement is the predominant pattern. The distal colon is more frequently involved. SF contrary to the conventional literature is not disproportionately involved in IC.

Colorectal emergencies and related complications: a comprehensive imaging review--imaging of colitis and complications

OBJECTIVE

Colorectal emergencies are a common presentation in the emergency medicine setting and their timely diagnosis plays a crucial role in avoiding dreaded complications. The quintessential role of a radiologist lies in identifying the cause, narrowing the differential diagnosis according to imaging features, and, most importantly, identifying the associated complications.

CONCLUSION

This review focuses on imaging features of the spectrum of colitides and the complications related to colitides.

Radiographical evaluation of ulcerative colitis

Radiographical modalities have become important diagnostic tools in cases of ulcerative colitis (UC). Imaging can be used non-invasively to determine the extent of involvement, severity of disease and to detect disease-related complications and extra-intestinal inflammatory bowel disease (IBD) manifestations. While abdominal X-rays and barium enemas still retain their relevance in specific clinical settings, the use of computed tomography enterography (CTE) or magnetic resonance enterography (MRE) are now used as first-line investigations to exclude active small bowel disease in IBD patients and can be utilized to detect active colonic inflammation. Additionally, CT colonography and MR colonography are emerging techniques with potential applications in UC. Ultrasonography, leukocyte scintigraphy and positron emission tomography are novel abdominal imaging modalities currently being explored for IBD interrogations. This plethora of radiological imaging options has become a vital component of UC assessments.

Is CT Angiogram of the Abdominal Vessels Needed following the Diagnosis of Ischemic Colitis? A Multicenter Community Study

Background. CT angiogram is frequently obtained after diagnosis of ischemic colitis (IC). Aims. To investigate the vascular findings of CT angiogram as compared to contrast-enhanced CT scan and whether this modality changes the management or prognosis of IC. Methods. We conducted a retrospective analysis of patients with IC from 2007 to 2013. Results. CT angiogram was performed in 34 patients (28.81%), whereas contrast-enhanced CT scan was performed in 54 patients (45.76%). In CT angiogram group, 8 patients (23.5%) had atherosclerotic changes. Stenosis was found in 12 patients (35.3%) (9: celiac trunk, 3: SMA). Among this group, one patient underwent colectomy and another underwent angioplasty of the celiac trunk who died within 30 days. Among contrast-enhanced CT scan group, 5 patients (9.3%) had atherosclerotic changes. Stenosis was found in 5 patients (9.3%) (3: celiac trunk, 1: SMA, and 1: IMA). Among this group, 3 patients had colectomy and one died within 30 days. There was no statistical difference between both groups in all vascular findings except the stenosis which was higher in CT angiogram group (P = 0.0025). Neither the need for surgery nor all-cause mortality was different between both groups. Conclusion. CT angiogram did not provide any useful findings that altered the management or the prognosis of IC.

Colorectal cancer in inflammatory bowel diseases: CT features with pathological correlation

PURPOSE

To describe CT features of inflammatory bowel disease (IBD)-related colorectal cancer and correlate the imaging findings with histopathological findings.

MATERIALS AND METHODS

CT imaging findings in 17 patients with IBD-related colorectal cancer were retrospectively evaluated. Imaging findings were correlated with surgical and histopathological findings. Univariate and multivariate analyses explored the relationships between CT and histopathological variables.

RESULTS

Two different CT patterns were individualized including clearly visible soft tissue mass (8/17; 47%) (Type 1 tumor) or stenosis with marked circumferential thickening resembling inflammation (9/17; 53%) (Type 2 tumor). At univariate analysis, thickness of tumor-free colorectal wall at CT was greater in Crohn disease (median, 13 mm) than in ulcerative colitis (median, 7 mm) (P = 0.011). Significant association was found between presence of signet ring cells and Type 2 tumor at CT (6/9, 67% P = 0.009) and colonic dilatation proximal to tumor (5/6, 83%; P = 0.035). At multivariate analysis, free-fluid effusion was the single independent CT variable predictive for the presence of signet ring cells (odds ratio = 50; 95% CI 2.56-977.02; P = 0.01).

CONCLUSION

Colorectal cancer in IBD displays two main features on CT. Type 2 tumors and free-fluid effusion correlate with presence of signet ring cells. Knowledge of these findings is critical to help suggest the diagnosis.

Bowel wall thickening at CT: simplifying the diagnosis

Objective

In this article we present a simplified algorithm-based approach to the thickening of the small and large bowel wall detected on routine computed tomography (CT) of the abdomen.

Background

Thickening of the small or large bowel wall may be caused by neoplastic, inflammatory, infectious, or ischaemic conditions. First, distinction should be made between focal and segmental or diffuse wall thickening. In cases of focal thickening further analysis of the wall symmetry and perienteric anomalies allows distinguishing between neoplasms and inflammatory conditions. In cases of segmental or diffuse thickening, the pattern of attenuation in light of clinical findings helps narrowing the differential diagnosis.

Conclusion

Focal bowel wall thickening may be caused by tumours or inflammatory conditions. Bowel tumours may appear as either regular and symmetric or irregular or asymmetric thickening. When fat stranding is disproportionately more severe than the degree of wall thickening, inflammatory conditions are more likely. With the exception of lymphoma, segmental or diffuse wall thickening is usually caused by benign conditions, such as ischaemic, infectious and inflammatory diseases.

Key points

• Thickening of the bowel wall may be focal (<5 cm) and segmental or diffuse (6-40 cm or >40 cm) in extension.

• Focal, irregular and asymmetrical thickening of the bowel wall suggests a malignancy.

• Perienteric fat stranding disproportionally more severe than the degree of wall thickening suggests an inflammatory condition.

• Regular, symmetric and homogeneous wall thickening is more frequently due to benign conditions, but can also be caused by neoplasms such as well-differentiated adenocarcinoma and lymphoma.

• Segmental or diffuse bowel wall thickening is usually caused by ischaemic, inflammatory or infectious conditions and the attenuation pattern is helpful in narrowing the differential diagnosis.

MDCT assessment of ulcerative colitis: radiologic analysis with clinical, endoscopic, and pathologic correlation

PURPOSE

Evaluate the utility of multidetector-row computed tomography (MDCT) in assessing the severity of ulcerative colitis (UC) in comparison with clinical assessment, colonoscopy, and histopathology.

MATERIALS AND METHODS

Patients with UC evaluated with at least one abdominal contrast-enhanced CT study (CECT) within 7 days of colonoscopy with biopsy were included. CECT of 23 patients (12 male; mean age 40 years; age range, 20-72 years) were retrospectively evaluated in consensus by two radiologists. A total of 138 lower GI tract segments were evaluated by CECT and graded for the presence of bowel wall thickening, mucosal hyperenhancement, mural stratification, mesenteric hyperemia, pericolonic stranding, and lymph nodes. A cumulative CT severity score was calculated and correlated with clinical, colonoscopic, and histopathologic severity grades.

RESULTS

The cumulative CT score and individual CECT scores for bowel wall thickening, mucosal hyperenhancement, and mural stratification showed positive correlation with clinical severity (P < 0.05). All individual CECT features as well as the cumulative CT score demonstrated statistically significant correlation with colonoscopic severity (P < 0.0001). Only wall thickening on CECT demonstrated significant correlation with histopathologic severity (P = 0.01).

CONCLUSION

Disease severity assessment by MDCT demonstrates positive correlation with severity established by clinical assessment and colonoscopy. Only increasing wall thickness, as graded on MDCT, correlates with histopathologic disease severity.

Multidetector computed tomography in large bowel lesions-a study of 100 cases

This study aims to evaluate the role of multidetector computed tomography (MDCT) in detecting and classifying the large bowel lesions. A prospective study of 100 adult patients was conducted from June 2007 to October 2009. Rectal and IV contrast were used for three dimensional reconstruction. Angiography was performed in cases of suspected ischemic pathology. CT colongraphy was done to evaluate adenomas. CT findings were correlated and confirmed by either colonoscopy, biopsy, postoperative findings or follow-up CT. The pathologies were common in 50-70 yrs (44%). M: F ratio was 2:1. Malignant lesions were seen in (55%) followed by inflammatory lesions in 26%, diverticulitis and ischemic colitis in 6% each. Miscellaneous conditions like polyps, volvulus and intussusceptions were seen in 7%. Adenocarcinoma was the common malignancy (81.2%). Present study showed that adenocarcinomas were associated with marked thickening of bowel wall (>1.5 cm) in 85.4% of patients, asymmetrical wall thickening (96.4%), focal involvement (length <10 cm) in 85.5% with heterogeneous post contrast enhancement (96.3%). Inflammatory lesions showed mild thickening (69%),segmental or diffuse involvement (77%), symmetrical wall thickening (89%) and homogenous post contrast enhancement (81%). Ischemic lesions showed marked thickening (83.4%), symmetrical thickening (100%) and homogenous enhancement (100%). Diverticulitis showed marked thickening (100%), asymmetrical wall thickening (66.7%) with heterogeneous post contrast enhancement (100%), with pericolic fluid. Arterial/venous thrombosis was diagnosed in 66.66%. Three per cent had benign adenomatous polyps on CT colonographic studies. MDCT was accurate in 98.2% cases for differentiating between benign and malignant etiology and is the modality of choice.

Noninvasive radiologic imaging of the large intestine: a valuable complement to optical colonoscopy

PURPOSE OF REVIEW

Radiologic imaging of the large intestine continues to evolve and expand the potential for noninvasive diagnosis. The aim of this review is to provide an update on current and emerging clinical capabilities for a variety of radiologic diagnostic imaging tools for evaluating the colon and rectum.

RECENT FINDINGS

The utility of computed tomography for the evaluation of symptomatic inflammatory and neoplastic conditions of the colon is well established, but the clinical role of computed tomography colonography is rapidly evolving. In addition to a number of diagnostic indications, computed tomography colonography is emerging as a potential frontline colorectal screening test for cancer prevention. MRI has become increasingly valuable for rectal cancer staging and inflammatory bowel disease but has yet to gain momentum for polyp evaluation. PET imaging has been primarily utilized for oncologic indications, but also holds considerable potential for inflammatory conditions. Other imaging modalities, such as the barium enema, conventional radiography, and ultrasound, play a much more limited role.

SUMMARY

Advances in radiologic imaging of the colorectum will continue to expand the capabilities and clinical indications for noninvasive diagnosis, allowing for a greater emphasis on the complementary roles of tissue sampling and therapy with optical colonoscopy.

Endoscopic findings and clinicopathologic characteristics of ischemic colitis: a report of 85 cases

Ischemic colitis is the most common type of intestinal ischemia and has a clinical spectrum of injury that ranges from mild and transient ischemia to acute fulminant colitis. The aim of this study was to explore endoscopic findings and clinicopathologic characteristics of ischemic colitis and be accurate enough to avoid missed diagnosis or misdiagnosis. A retrospective analysis was undertaken of endoscopy findings and clinicopathologic characteristics of 85 cases of ischemic colitis from March 2005 to April 2008 in the endoscopy center of our hospital. All cases underwent colonoscopy with biopsy within 2 weeks of the onset of symptoms, and all specimens with forceps were stained with hematoxylin-eosin and observed under light microscopy. Of the 85 cases of ischemic colitis (24 men and 61 women, average age 61.36 +/- 14.49 years old, range 29-84), 71 were over 50 years of age. These cases were associated with the basal diseases such as hypertension, cardiovascular disorders, diabetes, and hematological diseases as well as a history of abdominal operation. The clinical features usually presented with sudden onset of abdominal pain, diarrhea, and hematochezia. Ischemic lesions were located mainly in the left colon with segmental form (only descending colon affected 16%, only splenic flexure 14%, and only sigmoid colon 23%). The 85 patients consisted of the non-gangrenous type (82), which were composed of reversible IC (76) and chronic IC (6), and the gangrenous type (3). Endoscopic appearance of the transient ischemic colitis consisted of petechial hemorrhages, edematous and fragile mucosa, segmental erythema, scattered erosion, longitudinal ulcerations, and sharply defined segment of involvement. Ischemic colitis of stricture was characterized by full-thickness mucosa, lumens stricture, and diseased haustrations. The mucosa of gangrenous colitis with cyanotic and pseudopolyps was endoscopically observed as well. Clinicopathologic characteristics showed mucosal inflammation accompanied by erosion, granulation tissue hyperplasia and gland atrophy, lamina propria hemorrhage, and macrophages with hemosiderin pigmentation in submucosa in particular. Although endoscopy findings and clinicopathologic characteristics of ischemic colitis are nonspecific, colonoscopy with biopsy plays a vital role in the early diagnosis of ischemic colitis.

Role of CT colonography in inflammatory bowel disease

CT colonography (CTC), or virtual colonoscopy, is a non-invasive imaging method that uses CT data sets combined with specialized imaging software to examine the colon. CTC is not used routinely in patients with inflammatory bowel disease (IBD). However, investigating contemporarily the colon, other abdominal organs and the peritoneum with CTC is at times useful in patients with IBD, especially when other diagnostic tools fail. Furthermore, since symptoms of colorectal cancer sometimes superimpose to those of inflammatory disease, it may happen to image patients with IBD incidentally. If clinical signs are suggestive for inflammatory disease, exam technique should be modified accordingly and distinguishing radiological findings searched for.

Intramural Fat in the Duodenum and Proximal Small Intestine in Patients with Celiac Disease

OBJECTIVE

The purpose of this article is to describe and illustrate intramural fat in the duodenum and jejunum, to our knowledge a previously undescribed finding in celiac disease.

CONCLUSION

Celiac disease is known to produce inflammation of the duodenum and jejunum. We propose that postinflammatory intramural fat deposition occurs in a distribution likely unique for celiac disease. CT scans of the chest and abdomen obtained for many indications include these portions of the bowel. Celiac disease is now recognized as a common disease, and the recognition of intramural fat in the duodenum and jejunum on CT may allow earlier diagnosis.

Ischemic necrosis of the right colon in a patient with a ventricular assist device system

Despite improvements in medical therapy, the annual high mortality rate from end-stage heart failure continues. Although cardiac transplantation is a successful treatment for these patients, the shortage of donor hearts has led surgeons to seek other options. Ventricular assist device (VAD) technology is applied to a broader population of heart failure patients, and clinicians are confronted with the specialized perioperative and chronic care of patients who receive these devices. VAD implantation is now an acceptable means of bridging to heart transplantation. We report a case of isolated right colon necrosis in a patient with VAD, who was successfully treated with right hemicolectomy and ileocolostomy.

Fat halo sign in the bowel wall of patients with Crohn's disease

AIM

To evaluate the prevalence and localization of the deposition of submucosal fat, the "fat halo sign" (FHS), using computed tomography (CT) in the bowel wall of patients with Crohn's Disease, and to assess its relation to the duration of the disease.

MATERIALS AND METHODS

The abdominal CT examinations of 100 consecutive patients were reviewed for the presence of the FHS in the bowel wall. A measurement of less than -10HU was regarded as indicative of fat. CT findings were correlated with the duration of the disease and statistically tested by simple regression analysis. The patients were divided into two groups: group A included 26 patients with a disease duration of less than 1 year and group B included 73 with a longer disease duration. In one patient disease duration was unknown. To test the relationship between disease duration and FHS the cumulative number of FHS positive and negative patients was plotted against disease duration.

RESULTS

The FHS was present in 17 of the 100 patients in 20 bowel segments, mainly in the ileum (10) and the ascending colon (8). The FHS was present in 3.8% in group A and in 21.9% in group B (p<0.0375).

CONCLUSION

The FHS was present in 17% of patients with CD. Its location was mainly in the terminal ileum and ascending colon, typical sites of the disease. Its prevalence was significantly duration dependent.

CT imaging of colitis

Computed tomography (CT) is widely used to assess patients with nonspecific abdominal pain or who are suspected of having colitis. The authors recommend multidetector CT with oral, rectal, and intravenous contrast material and thin sections, which can accurately demonstrate inflammatory changes in the colonic wall and help assess the extent of disease. In most cases, the final diagnosis of the type of colitis is based on clinical and laboratory data and colonoscopic and biopsy findings, but specific CT features help narrow the differential diagnosis. Ulcerative colitis is distinguished from granulomatous colitis (Crohn disease) in terms of location of involvement, extent and appearance of colonic wall thickening, and type of complications. Ulcerative colitis and Crohn disease (granulomatous colitis) are rarely associated with ascites, which is often seen in infectious, ischemic, and pseudomembranous colitis. Pseudomembranous colitis also demonstrates marked wall thickening and, occasionally, skip areas but is associated with broad-spectrum antibiotic treatment or chemotherapy. Neutropenic colitis is characterized by right-sided colonic and ileal involvement, whereas ischemic colitis is characterized by vascular distribution pattern and history. Diverticulitis is a focal asymmetric process with fascial thickening and inflamed diverticula. Dilatation of a thick-walled appendix with increased enhancement and adjacent stranding suggests appendicitis, but inflammatory changes may extend to the cecum and terminal ileum. Epiploic appendagitis is a focal rim-enhancing area next to the colon, usually without any substantial colonic wall thickening.

CT enterography as a diagnostic tool in evaluating small bowel disorders: review of clinical experience with over 700 cases

Computed tomographic (CT) enterography combines the improved spatial and temporal resolution of multi-detector row CT with large volumes of ingested neutral enteric contrast material to permit visualization of the small bowel wall and lumen. Adequate luminal distention can usually be achieved with oral hyperhydration, thereby obviating nasoenteric intubation and making CT enterography a useful, well-tolerated study for the evaluation of diseases affecting the mucosa and bowel wall. Unlike routine CT, which has been used to detect the extraenteric complications of Crohn disease such as fistula and abscess, CT enterography clearly depicts the small bowel inflammation associated with Crohn disease by displaying mural hyperenhancement, stratification, and thickening; engorged vasa recta; and perienteric inflammatory changes. As a result, CT enterography is becoming the first-line modality for the evaluation of suspected inflammatory bowel disease. CT enterography has also become an important alternative to traditional fluoroscopy in the assessment of other small bowel disorders such as celiac sprue and small bowel neoplasms.