Optimal Distension Research Articles

Feasibility of Simple Oral Preparation Contrast-Enhanced CT Colonography (SOP-CE-CTC) Using Mannitol as a Neutral Oral Contrast Agent

Abstract Purpose This article prospectively assesses the feasibility of simple oral preparation contrast-enhanced computed tomography colonography (SOP-CE-CTC) using a large volume of oral 3% mannitol for good colonic distension along with mural and mucosal fold visualization. Methods A total of 100 patients in whom contrast CT abdomen was requested, recruited as per selection criteria, were advised to take mild oral bowel preparation for two nights, prior to the investigation. Then, after fasting overnight, they were asked to consume 1,500 to 2,000 mL of 3% mannitol solution in about an hour. Thirty minutes after completing the ingestion of oral mannitol, intravenous contrast was injected and SOP-CE-CTC was acquired at 55 seconds. Distension of six segments of the colon was evaluated by assigning scores 1 to 4 for qualitative assessment; and measuring the maximum luminal diameter of the colon, for quantitative assessment. Colonic mucosal and mural visualization were evaluated subjectively. All observations were recorded by two reviewers (with varying levels of experience) independently. Results On qualitative analysis, the colon showed optimal distension (score 4) in 58 to 89% cases on SOP-CE-CTC. There was agreement between both the reviewers in 89 to 99% cases (weighted kappa 0.820–0.979; p < 0.001). On quantitative analysis, the mean of the maximum colonic diameter ranged between 3.4 and 5.2 cm; and both the reviewers agreed in 89 to 97% cases (weighted kappa 0.777–0.967; p < 0.001). Mural and mucosal fold visualization in the proximal four segments of the colon was excellent (in 90–98%) but in the rectum and sigmoid it was 45 and 66%, respectively; both the reviewers agreed in 100% cases (weighted kappa 1.0 and p < 0.001). Conclusion Good colonic distension, mural, and mucosal fold visualization can be achieved on SOP-CE-CTC using 1,500 to 2,000 mL of 3% oral mannitol and mild oral bowel preparation agents.

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

ObjectivesThe 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 methodsRecruitment 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. ResultsCTE provided the best distension of jejunal loops (median diameter 27mm, range 17–32mm) 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). ConclusionsCTE 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.

Feasibility of 3-T MRI for the evaluation of Crohn disease in children

Crohn disease (CD) is a chronic inflammatory bowel disease that can affect any part of the gastrointestinal tract from the oral cavity to the anal canal. It occurs in all ages and is a significant cause for morbidity in children. Interest in MRI evaluation of CD has increased because of the concern regarding cumulative radiation dose from contrast fluoroscopic studies and CT. Several reports have demonstrated MRI to be a useful technique for CD. Most of these studies were performed at 1.5-T field strength. Imaging at a higher field strength, with a greater signal-to-noise ratio, has the potential of reducing scan times and increasing the resolution. However, there is a concurrent increase in artefacts, and these can be pronounced with abdominal imaging at 3 T. To determine the feasibility of 3-T MRI for CD in children and to assess the value of different sequences and the effect of artefacts that could potentially limit the role of bowel MR imaging at higher field strengths. A retrospective study of 46 children with biopsy-proven CD (ages 8-19 years, 53% boys) was performed. Sixty-eight consecutive MRI studies were performed on a 3-T scanner between 2005 and 2007; 42 of the abdomen (62%) and 26 of the pelvis/perineum (38%). Sorbitol was administered for the abdominal studies; orally for 36/42 (86%) studies and via a naso-jejunal (NJ) tube for 6/42 (14%) studies. For the abdomen, T2-W half-fourier acquisition single-shot turbo spin-echo (T2-W HASTE), true steady-state free precession (true FISP), pre-contrast and contrast-enhanced (CE) T1-volume interpolated gradient-echo (T1-W VIBE) and CE T1-W fast low-angle shot (T1-W FLASH) sequences were performed. For the perianal and pelvic assessment, fat-saturated T2-W turbo spin-echo (TSE), pre-contrast and CE T1-W FLASH or VIBE sequences were performed. The sequences were scored for diagnostic quality by two paediatric radiologists for visualisation of the bowel wall, whether normal or pathological and the visualization of extra intestinal manifestations. The effects of distension, susceptibility artefact and motion were assessed. Six (14%) abdominal MRI studies were normal. Thirty-six (86%) were abnormal with good correlation with endoscopic findings. The pelvic and perianal MRI studies were all abnormal (26/26, 100%) with good correlation with proctoscopy and examination under anaesthesia. All the sequences had high average scores (greater than or close to 3), except true FISP with a score of 2.4. The score was greatest in those who had NJ administration of sorbitol; however, satisfactory distension was also possible with oral administration of contrast. True FISP was the sequence most affected by a combination of suboptimal distension and artefact from colonic contents. With adequate distension, true FISP image quality improved remarkably. The overall score of this sequence was satisfactory in the absence of susceptibility and movement artefact. With appropriate attention to technique, with optimal distension and control of movement, high-quality, 3-T assessment of the abdomen, pelvis and perineum is possible. All sequences used at 1.5 T can be used at 3 T, however true FISP was the most prone to artefact.

A new method of anatomically conformal vaginal Cuff HDR brachytherapy

Objective HDR brachytherapy to the vaginal cuff using rigid intracavitary cylinders has a limited capacity to adapt to patient-specific anatomy. This study describes the use and dosimetry of a new method of anatomically conformal post-operative vaginal cuff HDR brachytherapy using an intra-vaginal balloon applicator. Methods Thirty consecutive patients with endometrial carcinoma underwent a hysterectomy and received adjuvant HDR brachytherapy in 6 weekly fractions using an intra-vaginal balloon. Optimal distension of the balloon to conform to the vaginal cuff was clinically determined to achieve complete balloon surface apposition with the vaginal mucosa and was confirmed radiographically. Radiation dose was prescribed to the vaginal mucosa and brachytherapy CT simulation was performed to optimize the irradiation dose in 3-D. Results 180 brachytherapy procedures were performed. The mean volume of balloon distension was 47.3 cc (range 20.8–83.8 cc; ± 11.3 cc). The mean dose from brachytherapy to the 2 cc volume of the bladder and rectum was 48.6% and 71.1% of the prescribed vaginal mucosal dose, respectively. Bladder and rectal doses increased as a function of balloon volume. 100% of the prescribed dose covered an average of 95.6% of the vaginal cuff. There were no acute complications or vaginal cuff recurrences at a mean follow-up of 13 months. Conclusions Post-operative vaginal cuff HDR brachytherapy using an intra-vaginal balloon applicator which conforms to the individual patient's vaginal cuff provides excellent radiation dose coverage of the vaginal mucosa with acceptable doses to the bladder and rectum.

Quality, clinical influence and tolerance of computed tomography enteroclysis in patients with suspected small bowel disease

Computed tomography enteroclysis (CTE) may be superior to other small bowel imaging techniques, detecting subtle mucosal lesions and extraluminal pathology. This study aimed to define the technical success, clinical influence and tolerance of CTE in patients with suspected small bowel disease. CTE scans of 42 consecutive patients (aged 21-78 years, 12 men) were reviewed by a single radiologist for technical adequacy and diagnosis. A panel of gastroenterologists reviewed clinical information. At a telephone interview, tolerance of CTE was graded numerically from 1 (unbearable) to 10 (excellent) and descriptively as unbearable, fair, good or excellent. Good or optimal distension of small bowel was achieved in 98%. The entire small bowel was imaged in 88%. Eighteen patients had a normal small bowel, whereas 12 (29%) had active small bowel Crohn disease, 4 intussusception, 3 small bowel diverticula and 7 having other diagnoses. Mesenteric lymphadenopathy was evident in 11 and fat stranding in 5. CTE resulted in a new or altered diagnosis in 13 (31%) patients and identified more extensive Crohn disease in a further 8 (19%). A change in management plan was instituted in 18 (43%) patients, with subsequent clinically significant improvement in 12. 33 (85%) described the procedure as 'fair' or 'unbearable' rather than 'good' or 'excellent'. The median tolerance score was 3 out of 10. CTE provided high-quality images in nearly all patients and had an effect on diagnosis, management or outcome in most, but was not well tolerated.

Esophageal cancer: pneumo-64-MDCT

Pre-surgical characterization and staging of esophageal cancer with only one imaging method could be useful since gastric invasion determines the scope of resection and the kind of surgery to be performed. Our aim is to demonstrate the usefulness of Pneumo-64-MDCT (PnCT64) in the presurgical characterization of esophageal neoplasms in correlation with surgical findings. A total of 50 patients with diagnosis of esophageal neoplasm were prospectively studied. A 14 French Foley catheter was used transorally in all patients. Air was instilled through the catheter to achieve esophageal distension. A 64-row MDCT scan was performed and the tumor was characterized according to scope, shape and anatomic location by using multiplanar 3D reconstructions and virtual endoscopy. Wall infiltration and presence of adenopathies were analyzed. Adequate gastroesophageal distension was achieved in all patients. In 44/50 patients, wall thickening was observed, and in 34/50 regional adenopathies were found. In 29/50 patients the lesion was found in the lower third and in the gastroesophageal junction. The surgical correlation for wall infiltration was 85.7%. PnCT64 proved to be useful and safe for identification of esophageal wall thickening and presurgical characterization. Optimal distension allowed definition of both upper and lower borders of the tumors located in the gastroesophageal junction, of utmost importance to determine the surgical approach.

Diagnostic value of CTE in patients with Crohn's disease

The goal of our study was to compare the accuracy of computed tomography enteroclysis (CTE) to that of biopsy in detecting bowel wall alterations of the terminal ileum in Crohn's disease (CD). A total of 43 patients with either diagnosed or suspected CD (16 females, 28 males) underwent CTE and ileoscopy. Ileoscopy diagnosed 35 patients with CD of the ileum, while 8 patients served as the control group. Computed tomography enteroclysis detected CD in 31 patients (88%) and in none of the control group. According to the criteria used for evaluation of small bowel loop distension, 31 cases were (72%) with optimal distension, nine cases (%21) with good distension, and three cases (7%) with poor distension. Computed tomography enteroclysis showed that mean ileal wall thickness in patients with CD was 6.8 mm (range, 9.5-4.1 mm) and 1.79 mm in patients in the control group (range, 2.20-1.38 mm). Mean postcontrast wall density in patients with CD was 81.9 HU (range, 111.6-52.2 HU) and 41.1 HU (range, 49.8-22.4 HU) in the control group. Mean postcontrast wall density in 17 patients with active CD was 97 HU (range, 67-123 HU) and 62 HU (range, 46-87 HU) in 18 CD patients in remission. We calculated that the overall sensitivity and specificity of CTE in detecting the severity of CD were 89% and 100%, respectively. Positive predictive value was 100%; negative predictive value was 89%. Our results indicate that CTE can reveal CD involvement of small bowel accurately and allow assessment of the degree of disease activity.

Modulation of peristalsis by NK3 receptor antagonism in guinea‐pig isolated ileum is revealed as intraluminal pressure is raised

1. NK(3) tachykinin receptors mediate slow excitatory transmission in the enteric nervous system and play a role in reflexes induced by the intestinal stretch or mucosal compression. However, there is little evidence to suggest that these receptors are important in peristalsis. We have examined the effects of the NK(3) receptor antagonist, talnetant, on peristalsis in guinea-pig isolated ileum induced by optimal and by supra-maximal distension pressures. 2. At the guinea-pig NK(3) receptor, talnetant was shown to have high affinity (pK(B) 8.8) and selectivity over the guinea-pig NK(1) and NK(2) receptors. 3. Peristaltic waves in the ileum elicited by optimal distension pressures (1-3 cmH(2)O) were unaffected by talnetant at a supra-maximal concentration (250 nm). 4. Distension at a higher pressure (4 cmH(2)O) induced peristalsis in which there was incomplete closure of the lumen during each peristaltic wave and an increase in the periods of inactivity observed between bursts of peristaltic activity. The addition of talnetant (250 nm) increased the number of peristaltic events by reducing these periods of inactivity and thus, increased the productivity of the peristaltic reflex. 5. The data suggest that NK(3) receptors are not involved in the modulation of peristaltic movements by physiological stimuli, but they may have a role in modulation of reflexes in extreme or pathological conditions.

Gel instillation sonohysterography: first experience with a new technique

A practical attempt to simplify and improve the technique of artificial uterine cavity distension by instilling gel instead of flushing saline. Prospective observational study. Teaching hospital. One hundred twenty patients with an indication for sonohysterography (abnormal uterine bleeding, exclusion of congenital abnormalities, or preoperative or postoperative evaluation of submucous myomas, polyps, or synechiae). A hydroxyethylcellulose gel containing anesthetic and antiseptic agents was instilled in the uterine cavity through a plastic intrauterine insemination cannula attached to a flexible plastic tube and a syringe. Transvaginal (3-dimensional) ultrasonography was performed concomitantly. Stable filling of the uterine cavity allowing a high-quality ultrasonographic visualization. An optimal distension of the uterine cavity could be achieved with an average of only 4 mL (range, 2-10 mL) in 113 patients. As expected, a stable filling of the uterine cavity permitted a precise visualization of the uterine cavity and its linings and offered an optimal presentation for a 3-dimensional ultrasound recording and reconstruction. Gel instillation is a simple technique with minimal inconvenience for the patient and seems to be an attractive alternative to saline infusion during sonohysterography.

Dose optimization of mannitol solution for small bowel distension in MRI.

To optimize the dose of a hydro solution containing 2.5% mannitol and 0.2% locust bean gum (LBG) for small bowel MRI in terms of bowel distension and patient acceptance. A total of 10 healthy volunteers ingested a hydro solution containing 2.5% mannitol and 0.2% LBG. Four different volumes (1500, 1200, 1000, and 800 ml) were assessed on four different examination days. Small bowel distension was quantified on coronal two-dimensional TrueFISP images by measuring the diameter of eight bowel loops throughout the jejunum and the ileum. In addition, volunteer acceptance was evaluated for every single examination by using a questionnaire. Optimal distension was obtained with either, 1000, 1200, or 1500 ml, with no statistically significant differences in distension between these groups. Administration of 800 ml led to significantly less distension of the small bowel. Significantly less side effects were noted using either 800 or 1000 ml compared to using larger volumes. We recommend a dose of 1000 ml mannitol/LBG solution as an oral contrast agent for optimal bowel distension and minimal side effects.

T1-weighted excretory MR urography using GD-DTPA after low-dose diuretic administration

Assessment of the morphology of the urinary tract by gadolinium (Gd)-enhanced T1-weighted MR-urography (MRU) and precontrast diuretic injection. MRU was performed in 5 patients using Gd-DTPA-enhanced coronal T1-weighted 3D-gradient-echo sequences with different spatial resolution. Prior to contrast injection, 10 mg of furosemide were administered intravenously. Secondary to the precontrast furosemide injection, the increase of the renal excretion rate allows complete visualisation of the entire collecting system within 10 minutes following Gd injection. Maximum intensity projections provide a three-dimensional overview of the ureters separate from the bladder. To achieve detailed anatomic imaging of the calices, both optimal distension and high resolution sequences are prerequisites which cannot be realized by means of survey urograms only. Contrast-enhanced excretory MRU performed after injection of a diuretic offers a rapid approach to visualising the morphology of the nondilated urinary tract. Imaging of caliceal details must be done with high-resolution 3D-gradient-echo sequences.

756 Rectal balloon for CT of rectal cancer clinical applications and methods

CT plays an important role for the pre-surgical evaluation of rectal cancer, both for staging versus RT and for planning the operation. Pelvic scans provide the surgeon with a complete, readable map of the anatomy. The aim of the study is to optimise the protocol for CT of rectal cancer. The luminal distension of visceral wall has been obtained in a clean, well tolerable way by using a balloon catheter filled with water. The catheter is positioned in the rectum at the level of the neoplastic lesion. It consists of a 20 cm long latex balloon 6 cm in diameter, assembled over 12F double-way polyethylene catheter: one to inflate the balloon, the second for a guidewire, both for giving stiffness to the system, to advance it and to make the catheter radiopaque to evaluate the correct positioning by CT Fluoroscopy or Scout View. The balloon in gently injected with water, monitoring the degree of distension on minimal discomfort complained by the patient. Optimal distension is usually obtained by injecting 100–200 ml of water. The patient decubit is determined by the position of the lesion leaving it sloping. The scans are performed by a General Electric Pro Speed. After the exam without contrast, 80 ml bolus of lopamidol 370 is injected in 60′. CT with the rectal balloon allows a precise evaluation of a series of parameters important for the pre-surgical staging: the distance between anal sphincters and tumor, extension of the tumor and the invasion of perirectal fat and surrounding structures, lymphnodes metastases. The execution of this exam is simple and clean. Rectal distension is well tolerated by patients, without complaints as when entire colon is involved. Avoiding the injection of contrast material in the colon, the CT doesn’t interfere with other exams that can be executed on the same day. The quality of images allows a high diagnostic accuracy.