Detection of colorectal tumors with water enema-multidetector row computed tomography

Other imaging techniques: Double-contrast barium enema, endoscopic ultrasonography, multidetector CT enema, and computed tomography colonoscopy

Double-contrast barium enema (DCBE), transrectal endoscopic ultrasonography (REU), multidetector computerized tomography enema (MDCT-e), and computed tomography colonoscopy (CTC) have been successfully used for the diagnosis of bowel endometriosis. DCBE provides a complete overview of the entire colon and allows detecting cecal nodules. The accuracy of DCBE is operator dependent and, thus, it may have low specificity. It does not allow identifying the cause of the mass effect. DCBE requires the administration of barium and exposure to radiation. REU precisely estimates the distance between the rectosigmoid nodule and the anal verge. However, it allows investigating only the distal part of rectosigmoid, it misses anterior pelvic lesions, and it has poor sensitivity for the diagnosis of endometriomas. MDCT-e is accurate and reproducible in diagnosing intestinal endometriosis and in assessing its characteristics: the largest diameter of the nodule, the distance between the distal part of the nodule and the anal verge, and depth of infiltration of endometriosis in the intestinal wall. MDCT-e requires the administration of iodinated contrast medium (CM) and the exposure to radiations. CTC has good performance in the diagnosis of rectosigmoid endometriosis. It allows estimating the degree of intestinal stenosis CTC, and the distance between the intestinal endometriotic nodule and the anal verge. It requires exposure to radiations, and it may require the administration of an iodinated CM.

Imaging the operated colon using water-enema multidetector CT, with emphasis on surgical anastomoses

Water-enema multidetector CT (WE-MDCT) provides a detailed multiplanar visualisation of mural, intra- and extraluminal abnormalities of the large bowel, relying on preliminary bowel cleansing, retrograde luminal distension, pharmacological hypotonisation and intravenous contrast enhancement. In patients with a history of colorectal surgery for either carcinoma or Crohn's disease (CD), WE-MDCT may also be performed via a colostomy, which allows depicting the anatomy and position of the residual large bowel and evaluates the calibre, length, mural and extraluminal features of luminal strictures. Therefore, WE-MDCT may prove useful as a complementary technique after incomplete or inconclusive colonoscopy to assess features and suspected abnormalities of the surgical anastomosis, particularly when endoscopic or surgical interventions are being planned. This pictorial essay presents the WE-MDCT technique and pitfalls, the expected appearances after different colic surgeries and the imaging features of benign anastomotic disorders (fibrotic stricture, kinking, inflammatory ulcer) and of locally recurrent tumours and CD.

TEACHING POINTS

• Water-enema multidetector CT (WE-MDCT) effectively visualises the operated colon • Complementary to endoscopy, WE-MDCT may helpfully depict abnormalities of surgical anastomoses • WE-MDCT allows assessment of strictures' features and abnormalities of the upstream bowel • Technical pitfalls, normal postsurgical findings and benign anastomotic disorders are presented • WE-MDCT allows detecting relapsing Crohn's disease, recurrent and metachronous tumours.

Value of water enema computed tomography in elderly symptomatic patients

BACKGROUND AND STUDY AIMS

Colonoscopy remains the gold standard for the examination of the colon. However, its use in the elderly is not well tolerated, and there is often a need for general anaesthesia, thus increasing the risk, especially if there are co-morbidities. Water enema computed tomography has been suggested to be a satisfactory alternative as a non-invasive, fast and effective means for the diagnosis of colorectal supra-centimetric lesions. The aim of our study was to assess the performance of water enema computed tomography as first-line examination by calculating its negative predictive value (NPV) for the diagnosis of supra-centimetric lesions in symptomatic elderly referred to colonoscopy.

PATIENTS AND METHODS

This was a prospective study including 57 symptomatic patients older than 65 years. All patients were explored by water enema computed tomography at first, followed by colonoscopy, and responded to a questionnaire on the tolerance to the preparation and both procedures.

RESULTS

The mean age of patients was 73 years. The M:F sex ratio was 1.59. The most frequent indication for colonoscopy was bowel disorders associated with abdominal pain (30%). Water enema computed tomography allowed the diagnosis of tumours (n = 2), polyps (n = 6), diverticulosis (n = 7), inflammatory wall thickening (n = 1) and extra-colic lesions (n = 28). NPV of water enema computed tomography for supra-centimetric lesions was 96.5%. Sensitivity and specificity were 87.3% and 98%, respectively. However, for sub-centimetric lesions, water enema computed tomography had a low sensitivity estimated at 6%, specificity at 89.9%, positive predictive value at 91.9% and NPV at 27.7%.

CONCLUSION

Water enema computed tomography has proven to be a valuable and non-invasive method indicated as a first-line examination in case of colonic symptoms in the elderly to diagnose supra-centimetric lesions.

Dual Energy Spectral CT Imaging for Colorectal Cancer Grading: A Preliminary Study

Objectives

To assess the diagnostic value of dual energy spectral CT imaging for colorectal cancer grading using the quantitative iodine density measurements in both arterial phase (AP) and venous phase (VP).

Methods

81 colorectal cancer patients were divided into two groups based on their pathological findings: a low grade group including well (n = 13) and moderately differentiated cancer (n = 24), and a high grade group including poorly differentiated (n = 42) and signet ring cell cancer (n = 2). Iodine density (ID) in the lesions was derived from the iodine-based material decomposition (MD) image and normalized to that in the psoas muscle to obtain normalized iodine density (NID). The difference in ID and NID between AP and VP was calculated.

Results

The ID and NID values of the low grade cancer group were, 14.65±3.38mg/mL and 1.70±0.33 in AP, and 21.90±3.11mg/mL and 2.05± 0.32 in VP, respectively. The ID and NID values for the high grade cancer group were 20.63±3.72mg/mL and 2.95±0.72 in AP, and 26.27±3.10mg/mL and 3.51±1.12 in VP, respectively. There was significant difference for ID and NID between the low grade and high grade cancer groups in both AP and VP (all p<0.001). ROC analysis indicated that NID of 1.92 in AP provided 70.3% sensitivity and 97.7% specificity in differentiating low grade cancer from high grade cancer.

Conclusions

The quantitative measurement of iodine density in AP and VP can provide useful information to differentiate low grade colorectal cancer from high grade colorectal cancer with NID in AP providing the greatest diagnostic value.

Degree of colonic distension: intrapatient comparison between CT colonography and CT with water enema

PURPOSE

Compare colonic distension using CT colonography (CTC) and CT with water enema (CTWE) in the same patients.

METHODS AND MATERIALS

Twenty-seven patients who underwent both CTC and CTWE, considering separately supine (CTC-S) and prone (CTC-P) acquisition of CTC were included. The colon was divided into six segments, performing both a qualitative and quantitative analysis.

RESULTS

Adequate distension of sigmoid colon was more frequently achieved with CTC-P and CTWE compared to CTC-S (P<.05). CTC-P and CTWE showed better distension of the left colon compared to CTC-S (P<.01 and P=.03 regarding sigmoid colon, respectively; P=.01 and P=.03 regarding descending colon, respectively).

CONCLUSIONS

Computed tomography (CT) studies of the colon should be customized to fulfill the clinical query.

The diagnostic accuracy of pericolonic fat extension and attenuation for colorectal tumors

OBJECTIVE

To evaluate the utility of quantitative analysis of the extension and attenuation of pericolonic fat in the local staging of colorectal cancer (CRC) using multi detector computed tomography (MDCT).

MATERIALS AND METHODS

This was a retrospective study of 110 patients who were operated due to pathologically proven CRC from January 2007 to January 2010, and who underwent preoperative MDCT of the abdomen and pelvis with administration of intravenous contrast material and image acquisition during the portal venous phase. The mean age was 69 years (range of 38-90 years). Pathological reports were reviewed for TNM staging. All MDCT studies were reviewed by two certified radiologists for maximal and minimal tumor diameter, extent of the infiltrated pericolonic fat (measured in mm), attenuation of the infiltrated pericolonic fat (measured in Hounsfield units), and attenuation of normally appearing fat next to the tumor. The sensitivity and specificity of these parameters in detecting patients with ≥ T3 CRC were calculated.

RESULTS

The overall sensitivity, specificity, and accuracy of pericolonic fat infiltration in detecting patients with ≥T3 stage were 95% (95% CI, 89.0-98.7%), 20% (5.8-43.7%), and 81.9% (74.7-89%) respectively. The mean extent and attenuation of the infiltrated pericolonic fat, in addition to the maximal tumor diameter, were higher in the ≥T3 group (p<0.05). By defining threshold values to these parameters, the positive predictive value for detecting ≥T3 stage tumors approaches 100%.

CONCLUSION

Quantitative analysis of pericolonic fat increased the accuracy of MDCT in the detection of local tumor spread in CRC.

Water-enema multidetector computed tomography for planning surgery

PURPOSE

Water-enema multidetector computed tomography (WE-MDCT) is a technique for the localization and preoperative T- and N-stage assessments of colon cancer. It may be a useful tool for planning surgery. The primary aim of this study was to evaluate the diagnostic accuracy of WE-MDCT for T-staging and its ability to locate tumors for laparoscopy planning. The secondary aim was to assess reading reproducibility and diagnostic accuracy for the preoperative determination of N-stage.

METHODS

We performed a study to evaluate preoperative WE-MDCT for surgical planning in patients with symptomatic colon adenocarcinomas who underwent surgery between June 2010 and January 2014. A radiologist and a surgeon read the WE-MDCTs separately. Results were compared with colonoscopy and the surgical specimen.

RESULTS

Seventy-one patients (42 men (59.1%); mean age 73.1 years (range 45 to 95)) were included. Seventy-six tumors were assessed. The intraclass correlation coefficient (ICC) for location as determined by surgery and that determined by WE-MDCT was 1, and the ICC for location between colonoscopy and WE-MDCT was 0.85 (95% CI 0.75-0.91). For T-stage determination, sensitivity was 96 and 94% and specificity 83 and 88% for readers 1 and 2, respectively. The T-stage assessment allowed for the programing of surgical access and showed good sensitivity and specificity for the assessment of invasion in adjacent organs.

CONCLUSION

WE-MDCT is relatively easy to perform, and its results can be read effectively by radiologists and surgeons. WE-MDCT indicated the location of tumors perfectly and permitted a good determination of their T-stage. The technique is thus pertinent for the planning of laparoscopic surgery for colon cancer.

Water enema multidetector CT technique and imaging of diverticulitis and chronic inflammatory bowel diseases

BACKGROUND

Water enema multidetector computed tomography (WE-MDCT) is currently considered the most accurate imaging modality to provide high-resolution multiplanar visualisation of the colonic wall and surrounding structures.

METHODS

This pictorial review presents our experience with WE-MDCT applications outside colorectal tumour staging, particularly for investigating diverticular disease and chronic inflammatory bowel diseases. A detailed explanation of the technique is provided, including patient preparation, the acquisition protocol, and study interpretation.

RESULTS

WE-MDCT allows accurate preoperative visualisation of diverticular disease, acute and complicated diverticulitis. Ulcerative, indeterminate, or Crohn's colitis can be assessed including longitudinal distribution, mural thickening and enhancement patterns, pseudopolyps, associated perivisceral changes, adjacent organ involvement, and features suggesting carcinoma. Elective WE-MDCT represents a useful complementary technique in patients with impossible, incomplete, or inconclusive endoscopy, can allow study of a stricture's features and the upstream bowel, and helps planning medical, endoscopic, or surgical treatments.

CONCLUSION

Urgent WE-MDCT with limited or no bowel preparation may prove useful in acutely symptomatic patients, as it may obviate a risky or contraindicated endoscopy, can determine disease severity, and allows making correct therapeutic choices.

TEACHING POINTS

• Water enema multidetector CT provides high-resolution multiplanar visualisation of the colonic wall. • WE-MDCT allows accurate visualisation of diverticular disease, acute and complicated diverticulitis. • In chronic inflammatory bowel diseases WE-MDCT depicts the distribution, mural and perivisceral changes. • Elective WE-MDCT usefully complements incomplete endoscopy to assess strictures and upstream colon. • Urgent WE-MDCT with limited or no bowel preparation in acute diseases may obviate endoscopy.

Computed tomography of the bowel: a prospective comparison study between four techniques

OBJECTIVES

The major objective was to prospectively compare the grade of bowel distension obtained with four different computed tomography (CT) techniques dedicated for the examination of the small intestine (CT enteroclysis [CTE] and enterography [CTe]), of the colon (CT with water enema [CT-WE]), or both (CTe with water enema [CTe-WE]). The secondary objective was to assess patients' tolerance toward each CT protocol.

MATERIALS AND METHODS

Recruitment was designed to obtain four groups of the same number of patients (30). Each group corresponded to a specific CT technique, for a total of 120 consecutive outpatients (65 male and 55 female, mean age 51.09 ± 13.36 years). CTE was performed after injection of methylcellulose through a nasojejunal tube, while in the CTe protocol a polyethylene glycol electrolyte solution was orally administered to patients prior to the CT acquisition. In the CT-WE protocol intraluminal contrast (water) was administered only by a rectal enema, while CTe-WE technique included both a rectal water enema and oral ingestion of neutral contrast material to obtain a simultaneous distension of small and large bowel. CT studies were reviewed in consensus by two gastrointestinal radiologists who performed a quantitative and qualitative analysis of bowel distension on a per segment basis. The presence and type of adverse effects were recorded.

RESULTS

CTE provided the best distension of jejunal loops (median diameter 27 mm, range 17-32 mm) when compared to all the other techniques (p<0.0001). The frequency of patients with an adequate distension of the terminal ileum was not significantly different among the four groups (p=0.0608). At both quantitative and qualitative analysis CT-WE and CTe-WE determined a greater and more consistent luminal filling of the large intestine than that provided by both CTE and CTe (p<0.0001 for all colonic segments). Adverse effects were more frequent in patients belonging to the CTE group (p<0.0028).

CONCLUSIONS

CTE allows an optimal distension of jejunal loops, but it is the most uncomfortable CT protocol. When performing CT-WE, an adequate retrograde distension of the terminal ileum was provided in a particularly high percentage of patients. CTe-WE provides a simultaneous optimal distension of both small and large bowel.