CT and bowel disease

Role of Multi-Detector CT (MDCT) in Evaluation of Bowel Diseases

INTRODUCTION

Multi-Detector Computed Tomography (MDCT) has revealed excellent results in various systems of the body. Its role in abdominal imaging for solid viscera has been proved beyond doubt. It is an emerging non invasive tool for evaluation of bowel diseases.

AIM

To see the efficacy of MDCT in evaluation of various bowel diseases.

MATERIALS AND METHODS

The study was carried out in the Department of Radiodiagnosis and Imaging, Batra Hospital and Medical Research Centre, Delhi, India. A total of 60 patients were enrolled in this study from March 2008 to June 2010 over a period of 24 months. All patients suspected to have inflammatory, obstructive, ischaemic and neoplastic diseases of small or large bowel disease were included in the study. The patients with past history of chronic renal failure, allergic reaction to contrast were excluded from the study. Comparison was made between CT findings with the operative findings, endoscopy, angiography or histopathology correlation whichever was relevant with case. All this data was compiled and statistically analysed.

RESULTS

Out of 60 patients 12 patients were diagnosed having appendicitis using axial, Multiplaner Reconstruction (MPR) and curved MPR images. The findings of appendicitis were confirmed on surgery and subsequent histopathology correlation. Inflammatory bowel diseases comprised of 28 cases out of which seven persons were diagnosed with intestinal Koch's disease. Four patients had idiopathic inflammatory bowel diseases. Rest of the 17 patients were reported to have findings of non-specific colitis and they responded well with antibiotic treatment.

CONCLUSION

The sensitivity and specificity of MDCT in case of bowel obstruction clearly demonstrates not only the site of obstruction, but also reveal the cause of obstruction which includes intraluminal, intramural and extrinsic factors. CT scan categorizes the lesion to inflammatory or neoplastic to a greater accuracy. MDCT can also demonstrate the complications associated with obstruction like strangulation and perforation. CT is now considered a good tool in the evaluation of patients with suspected bowel obstruction, particularly in indeterminate clinical and conventional radiographic findings.

Systematic analysis of missed colorectal cancer cases and common pitfalls in diagnosis

BACKGROUND

Missed colorectal cancer on endoscopic or radiological investigations may delay diagnosis and impact outcome. This study audits incidence of previous investigations in patients with colorectal cancer, considers outcome in 'missed' cancer cases and examines the diagnostic pathway in the derived case series to identify common pitfalls in diagnosis.

METHODS

Patients diagnosed with colorectal cancer in 2011 at a single National Health Service (NHS) Trust were reviewed. Incidence of endoscopic and radiological investigations in the 3 years preceding diagnosis and outcome data were collected. Cases of prior investigation not leading to diagnosis were considered 'missed' cancers and survival compared with 'detected' cases. The diagnostic pathway in each 'missed' case was reviewed.

RESULTS

395 colorectal cancer cases were studied. Eighteen (4.6%) patients underwent previous investigation including colonoscopy (n=4), flexible sigmoidoscopy (n=5), barium enema (n=5) and diagnostic abdominal CT scan (n=12), median 708 days prior to diagnosis. Previous investigation predicted reduced overall and disease-free survival (HR 2.07, p=0.04 and HR 2.66, p<0.0001), after age and gender adjustment. Ten different categories termed 'pitfalls' were derived from analysis of the diagnostic pathway. These included CT scanning for abdominal pain without further investigation (n=7), rectosigmoid cancer following a previous diagnosis of diverticular disease (n=4) and incomplete diagnostic investigations without adequate follow-up (n=3).

CONCLUSIONS

A proportion of patients diagnosed with colorectal cancer have previously been investigated for gastrointestinal symptoms and survival appears reduced in these patients. Regular audit and analysis of previous investigations can identify common pitfalls in diagnosis, which should be used to inform training and improve practice.

Etiology of small bowel thickening on computed tomography

BACKGROUND

Abdominal pain is often evaluated using imaging, most often with computed tomography (CT). While CT is sensitive and specific for certain diagnoses, small bowel thickening is a nonspecific finding on CT with a broad differential diagnosis including infection, inflammation, ischemia and neoplasm.

METHOD

A review of medical records of patients who underwent CT scans of the abdomen and pelvis over a one-year period and exhibited small bowel thickening were retrospectively evaluated to determine the final diagnosis.

RESULTS

The etiologies of small bowel thickening on CT were as follows: infection (113 of 446 [25.34%]); reactive inflammation (69 of 446 [15.47%]); primary inflammation (62 of 446 [13.90%]); small bowel obstruction (38 of 446 [8.52%]); iatrogenic (33 of 446 [7.40%]); neoplastic (32 of 446 [7.17%]); ascites (30 of 446 [6.73%]); unknown (28 of 446 [6.28%]); ischemic (24 of 446 [5.38%]); and miscellaneous (17 of 446 [3.81%]).

CONCLUSION

Infectious and inflammatory (primary or reactive) conditions were the most common cause of small bowel thickening in the present series; these data can be used to formulate a more specific differential diagnosis.

Clinicopathological characteristics and survival analysis of primary duodenal cancers: a 14-year experience in a tertiary centre in South China

BACKGROUND

Primary duodenal cancer (PDC) is rare and few studies have addressed it adequately, especially in China. The present study is to evaluate the clinicopathological features and prognosis of PDC in Chinese patients.

PATIENTS AND METHODS

All the consecutive cases confirmed as PDC by histopathological analysis in The First Affiliated Hospital of Sun Yat-sen University between 1995 and 2008 were included. Clinicopathological details were retrospectively analysed and prognostic factors influencing survival were evaluated.

RESULTS

The patient cohort included 53 men and 38 women, accounting for only 0.02% of all in-patients during this period. Esophagogastroduodenoscopy and gastrointestinal barium radiography were mainstay diagnostic tests for PDC; they detected 88.6% and 83.3% of the tumours, respectively. Tumours mainly occurred in the descending portion of the duodenum (67.0%). Abdominal pain was the most frequent symptom (56.0%). Histologically, adenocarcinoma was the most common type (74.7%). The overall 1-, 3- and 5-year survival rates were 62.6%, 43.7% and 33.1%, respectively. Patients survived longer in the curative surgery group (median survival time of 45 months) than those in the palliative group (6 months) (P < 0.001). Nodal metastasis and positive resection margin had a significant negative impact on survival in patients undergoing potentially curative surgery in a univariate and multivariate model (P < 0.05).

CONCLUSION

Patients with PDC are rare and lack specific presentations. Esophagogastroduodenoscopy and gastrointestinal barium radiography are effective in screening this rare tumour. Nodal metastasis and positive resection margins are associated with a poor prognosis. A curative surgery that achieves complete resection with negative margin should be pursued.

Diagnostic ionizing radiation exposure in a population-based cohort of patients with inflammatory bowel disease

OBJECTIVE

For diagnosis, assessing disease activity, complications and extraintestinal manifestations, and monitoring response to therapy, patients with inflammatory bowel disease undergo many radiological studies employing ionizing radiation. However, the extent of radiation exposure in these patients is unknown.

METHODS

A population-based inception cohort of 215 patients with inflammatory bowel disease from Olmsted County, Minnesota, diagnosed between 1990 and 2001, was identified. The total effective dose of diagnostic ionizing radiation was estimated for each patient. Linear regression was used to assess the median total effective dose since symptom onset.

RESULTS

The number of patients with Crohn's disease and ulcerative colitis was 103 and 112, with a mean age at diagnosis of 38.6 and 39.4 yr, respectively. Mean follow-up was 8.9 yr for Crohn's disease and 9.0 yr for ulcerative colitis. Median total effective dose for Crohn's disease was 26.6 millisieverts (mSv) (range, 0-279) versus 10.5 mSv (range, 0-251) for ulcerative colitis (P < 0.001). Computed tomography accounted for 51% and 40% of total effective dose, respectively. Patients with Crohn's disease had 2.46 times higher total effective dose than ulcerative colitis patients (P= 0.001), adjusting for duration of disease.

CONCLUSIONS

Annualizing our data, the radiation exposure in the inflammatory bowel disease population was equivalent to the average annual background radiation dose from naturally occurring sources in the U.S. (3.0 mSv). However, a subset of patients had substantially higher doses. The development of imaging management guidelines to minimize radiation dose, dose-reduction techniques in computed tomography, and faster, more robust magnetic resonance techniques are warranted.

Pediatric abdominal applications of multidetector-row CT

The introduction of multidetector technology of computed tomography (CT) into clinical practice has increased using CT as modality of choice for most body parts. In spite of some disadvantages of CT such as radiation exposure and using iodinated contrast medium, some facilities gathered by multidetector computed tomography (MDCT) such as faster scanning time and high-resolution imaging technique have improved pediatric CT applications. Less using intravenous and oral contrast medium, less sedation rate, decreased radiation exposure are very practical advantages of MDCT in abdominal imaging of pediatric population. In this review, technical details of these advantages of MDCT for pediatric population and some examples of improved imaging and diagnostic capabilities arising from MDCT for pediatric abdominal applications will be presented.

Magnetic resonance imaging based colonography for diagnosis and assessment of diverticulosis and diverticulitis

BACKGROUND AND AIMS

MRI-based colonography is a new minimally invasive imaging modality to assess the colon and abdomen. This new method which is applied mainly for polyp screening could be an integrative approach for colonic diverticulitis assessment. This study evaluated the feasibility of MRI-based colonography to assess diverticulosis or diverticulitis.

PATIENTS AND METHODS

Fourteen consecutive patients with clinically suspected diverticulitis were examined by MRI colonography on a 1.5-T scanner. All patients underwent abdominal CT as gold standard. N-Butyl-scopalamin was given intravenously to reduce bowel peristalsis. After rectal administration of a T1-positive enema T1- and T2-weighted acquisitions with additional intravenous contrast were obtained. A 3D FLASH sequence was acquired for virtual colonography. The results were compared with CT and biological parameters such as white blood cell count and C-reactive protein.

RESULTS

Of 56 bowel segments (sigmoid colon, descending colon, transverse colon, ascending colon) in all 14 patients 54 were assessed to have good to fair image quality. Having CT as standard of reference, all sigmoid diverticula were diagnosed based on MRI. Inflammation as judged by CT was identically assessed on MRI. 3D models of the colon revealed further diverticula in the remaining colon; additionally, the 3D models gave a comprehensive image for surgical planning.

CONCLUSION

In our preliminary study MRI colonography revealed the same diagnosis as CT in all patients without ionizing radiation. Additionally, 3D-rendered models and virtual colonoscopy can be performed. This comprehensive 3D models could replace presurgical planning barium enema with concurrent assessment of the residual colon.

Modern imaging using computer tomography and magnetic resonance imaging for inflammatory bowel disease (IBD) AU1

Radiologic imaging--especially of the small bowel--plays an important role in the diagnosis and management of patients with inflammatory bowel disease. The radiographic examination of the small intestine with barium either as enteroclysis or as small bowel follow through are still the mainstays in small bowel imaging. However, abdominal CT or MRI, which has the advantage of not utilizing ionizing radiation, or the techniques of CT- or MR-enteroclysis, are overall comparable with regard to the sensitivity and specificity in detecting intestinal pathologies and have already replaced the conventional techniques in centers dedicated to the management of inflammatory bowel disease. Additionally, these cross-sectional imaging techniques provide, in a sense, a "one stop abdominal imaging workup," the diagnosis of extraluminal disease manifestations or complications. Future developments of CT- or MR-based virtual colonography and endoscopy in patients with inflammatory bowel disease are currently being investigated, but should momentarily be considered as purely experimental approaches.