Grey scale ultrasound in Crohn's disease

Bowel Ultrasound in Inflammatory Bowel Disease: How Far in the Grayscale?

Bowel ultrasound (BUS) is a non-invasive and accurate technique for assessing activity, extension of disease, and complications in inflammatory bowel diseases. The main advantages of BUS are its safety, reproducibility, and low costs. Ancillary technologies of BUS (i.e., color Doppler and wave elastography) could broaden the diagnostic power of BUS, allowing one to distinguish between inflammation and fibrosis. Considering the costs and invasiveness of colonoscopy and magnetic resonance, BUS appears as a fast, safe, and accurate technique. The objective measures of disease allow one to make clinical decisions, such as optimization, switch, or swap of therapy. Previous studies reported a sensitivity and a specificity of more than 90% compared to endoscopy and magnetic resonance. Lastly, transperineal ultrasound (TPUS) is a promising approach for the evaluation of perianal disease in Crohn’s disease (CD) and disease activity in patients with ulcerative proctitis or pouchitis. Bowel ultrasound is being incorporated in the algorithm of managing inflammatory bowel diseases. Transmural healing evaluated through ultrasonography is emerging as a complementary target for disease treatment. In this review, we aimed to summarize and discuss the current evidence on BUS in the management of inflammatory bowel diseases and to address the challenges of a full validation of this technique.

The establishment of a regression model from four modes of ultrasound to predict the activity of Crohn's disease

To establish a multi-parametric regression model from four modes of ultrasound to predict the activity of Crohn's disease (CD) noninvasively. Score of 150 of the Crohn’s Disease Activity Index (CDAI) was taken as the cut-off value to divide the involved bowel segments of 51 patients into the active and inactive group. Eleven parameters from four modes of ultrasound (B-mode ultrasonography, color Doppler flow imaging, contrast-enhanced ultrasonography and shear wave elastography) were compared between the two groups to investigate the relationship between multimodal ultrasonic features and CD activity. P < 0.05 was considered statistically significant. Parameters with AUC larger than 0.5 was selected to establish the prediction model of CDAI. Totally seven ultrasound parameters (bowel wall thickness, mesenteric fat thickness, peristalsis, texture of enhancement, Limberg grade, bowel wall perforation and bowel wall stratification) were significantly different between active and inactive group. A regression model was established based on the seven parameters as followed: CDAI = 211.325 + 3.186BWT − 53.003BWS + 6.280BWP + 0.392MFT + 22.239PS + 79.012LG + 72.793TE. (R² = 0.72, P = 0.037). The multimodal ultrasound parametric regression model was designed to predict CDAI score invasively. The model has the potential to provide an alternative method for quantifying the CD activity.

Utility of MR enterography and ultrasound for the investigation of small bowel Crohn's disease

Cross sectional Imaging plays an increasingly important role the diagnosis and management of Crohn's disease. Particular emphasis is placed on MRI and Ultrasound as they do not impart ionising radiation. Both modalities have reported high sensitivity for disease detection, activity assessment and evaluation of extra-luminal complications, and have positive effects on clinical decision making. International Guidelines now recommend MRI and Ultrasound in the routine management of Crohn's disease patients. This article reviews the current evidence base supporting both modalities with an emphasis on the key clinical questions. We describe current protocols, basic imaging findings and highlight areas in need of further research.

LEVEL OF EVIDENCE

5 Technical Efficacy: Stage 4 J. MAGN. RESON. IMAGING 2017;45:1573-1588.

WFUMB Position Paper. Learning Gastrointestinal Ultrasound: Theory and Practice

Gastrointestinal ultrasound (GIUS) is an ultrasound application that has been practiced for more than 30 years. Recently, GIUS has enjoyed a resurgence of interest, and there is now strong evidence of its utility and accuracy as a diagnostic tool for multiple indications. The method of learning GIUS is not standardised and may incorporate mentorship, didactic teaching and e-learning. Simulation, using either low- or high-fidelity models, can also play a key role in practicing and honing novice GIUS skills. A course for training as well as establishing and evaluating competency in GIUS is proposed in the manuscript, based on established learning theory practice. We describe the broad utility of GIUS in clinical medicine, including a review of the literature and existing meta-analyses. Further, the manuscript calls for agreement on international standards regarding education, training and indications.

Imaging techniques for assessment of inflammatory bowel disease: joint ECCO and ESGAR evidence-based consensus guidelines

The management of patients with IBD requires evaluation with objective tools, both at the time of diagnosis and throughout the course of the disease, to determine the location, extension, activity and severity of inflammatory lesions, as well as, the potential existence of complications. Whereas endoscopy is a well-established and uniformly performed diagnostic examination, the implementation of radiologic techniques for assessment of IBD is still heterogeneous; variations in technical aspects and the degrees of experience and preferences exist across countries in Europe. ECCO and ESGAR scientific societies jointly elaborated a consensus to establish standards for imaging in IBD using magnetic resonance imaging, computed tomography, ultrasonography, and including also other radiologic procedures such as conventional radiology or nuclear medicine examinations for different clinical situations that include general principles, upper GI tract, colon and rectum, perineum, liver and biliary tract, emergency situation, and the postoperative setting. The statements and general recommendations of this consensus are based on the highest level of evidence available, but significant gaps remain in certain areas such as the comparison of diagnostic accuracy between different techniques, the value for therapeutic monitoring, and the prognostic implications of particular findings.

Red chlorophyll: the new barium?

Imaging of gastrointestinal (GI) motility remotely through the abdominal wall has always been a tradeoff between resolution and invasiveness. Skin reflects and/or absorbs wavelengths of radiation in the ultraviolet and visible ranges, but is largely transparent to both high-energy radiation (Gamma to X-rays; <0.1-10 nm) and low-energy radiation (infrared to radio waves; 700 nm-10 m). Imaging using short wavelength radiation such as X-ray cinematography has excellent spatial and temporal resolution, but ionization can produce acute and long-term deleterious effects to the patient or animal. Other 'slice-based' imaging techniques such as ultrasound/MRI/CT minimize tissue damage, but are limited in the planar area that can be imaged in a timely fashion. This viewpoint article will summarize and explore the implications of recent advances in infrared imaging of the GI tract, in particular, an article published in this issue of NGM entitled 'In vivo dynamic imaging of intestinal motions using diet-related autofluorescence' in which the authors have used infrared imaging in combination with that most elusive ingredient, standard mouse chow, to capture the motions of the mouse GI tract.

Diagnostic accuracy of small intestine ultrasonography using an oral contrast agent in Crohn's disease: comparative study from the UK

AIM

To evaluate the usefulness of small intestine contrast-enhanced ultrasonography (SICUS) using an oral contrast agent in routine clinical practice by assessing the level of agreement with the established techniques, small bowel follow-through (SBFT) and computed tomography (CT), and diagnostic accuracy compared with the final diagnosis in the detection of small bowel Crohn's disease (CD) and luminal complications in a regional centre.

MATERIALS AND METHODS

All symptomatic known or suspected cases of CD who underwent SICUS were retrospectively reviewed. The level of agreement between SICUS and SBFT, CT, histological findings, and C-reactive protein (CRP) level was assessed using kappa (κ) coefficient. Sensitivity was demonstrated using the final diagnosis as the reference standard defined by the outcome of clinical assessment, follow-up, and results of investigations other than SICUS.

RESULTS

One hundred and forty-three patients underwent SICUS of these 79 (55%) were female. Eighty-six (60%) were known to have CD and 57 (40%) had symptoms suggestive of intestinal disease with no previous diagnosis. Forty-six (55%) of the known CD patients had had at least one previous surgical resection. The sensitivity of SICUS in detecting active small bowel CD in known CD and undiagnosed cases was 93%. The kappa coefficient was 0.88 and 0.91 with SBFT and CT, respectively. SICUS detected nine patients who had one or more small bowel strictures and six patients with a fistula all detected by SBFT or CT.

CONCLUSION

SICUS is not only comparable to SBFT and CT but avoids radiation exposure and should be more widely adopted in the UK as a primary diagnostic procedure and to monitor disease complications in patients with CD.

Ultrasound and inflammatory bowel disease

Transabdominal bowel sonography is a fast, efficient, and cheap way of examining the intestines. It is also virtually hazard-free and well accepted by patients. During the last 20 years, it has been established as a procedure for detecting bowel disease early in the diagnostic workup. Although rather unspecific, the method is sensitive for detection of bowel disease and can be applied to find the extent and location of inflammatory bowel disease. In patients with known ulcerative colitis and Crohn disease, it can also be used for follow-up because it is easily repeatable and radiation-free. Because it can be applied to find both intraluminal and peri-intestinal pathological features, it is a particularly valuable tool for the detection of complications of Crohn disease as stenosis, fistulas, and abscesses. Neither B-mode nor Doppler techniques have been proven obviously useful in categorizing disease activity, but new techniques using intravenous contrast might come closer to solving this question. Finally, recent longitudinal studies using transabdominal bowel sonography show that it can also give important prognostic information and be used for monitoring the effect of therapy.

Abdominal bowel ultrasound can predict the risk of surgery in Crohn's disease: proposal of an ultrasonographic score

OBJECTIVE

Abdominal bowel ultrasound (US) is widely used in the management of Crohn's disease (CD). The aim of this study was to evaluate the prognostic role of bowel-wall US morphology on the short-term risk of surgery.

MATERIAL AND METHODS

The 147 CD patients recruited in a case-control study comprised 49 cases operated on within 30 days after US examination and 98 matched non-operated controls. Clinical and US characteristics were analysed. Bowel-wall thickness was recorded, bowel-wall patterns were grouped into five types, but for final analysis they were grouped as "preserved" or "disrupted stratification".

RESULTS

Wall thickness and US patterns were significantly different between cases and controls (p<0.0001). A wall thickness >4.5 mm was observed in 45/49 cases and 47/98 controls (OR = 12.21), while "disrupted stratification" was observed in 34/49 cases and 12/98 controls (OR = 16.24). Among the clinical and US characteristics recorded, only 4 US variables were independently associated with surgery (pattern, thickness, presence of fistulae/abscesses and stenoses) and considered for the US score=(2.5*US pattern)+(1.5*Bowel thickness)+(3*Presence of fistulae/abscesses)+(1.5*Presence of stenoses). Based on this score, up to 84% of patients were correctly classified according to actual status (operated/non-operated).

CONCLUSIONS

Although it needs further prospective validation, the score we propose seems to be a reliable prognostic marker for the short-term risk of surgery in CD. In particular, the score points out those patients with an impending risk of surgery who need careful and frequent control in order to decide on the right time for surgery.

Is there an association between intestinal perfusion and Crohn's disease activity? A feasibility study using contrast-enhanced ultrasound

A recent study used contrast-enhanced ultrasound to assess splanchnic haemodynamics. This study investigates whether an association exists between disease activity and splanchnic transit time in patients with suspected Crohn's disease. The study protocol had the approval of the local ethics committee, and written informed consent was obtained. 18 patients (11 women; mean age, 40 years; age range, 23-69 years) with suspected or confirmed Crohn's disease were recruited prospectively. A bolus injection of an ultrasound contrast agent was given via a peripheral vein and time-intensity curves of the superior mesenteric artery and vein were analysed. Splanchnic transit time was calculated as the time interval between the rise in signal intensity to >10% above baseline value. Baseline parameters measured included the time-averaged maximum velocity and cross-sectional area of the superior mesenteric artery (SMA). Pearson correlations were used to test associations between different numeric measurements; the independent samples t-test was used to test associations between different numeric measurements; and the independent samples t-test was used to compare mean values between patients with active and inactive disease. There was a weak negative association between splanchnic transit time and the Crohn's Disease Activity Index (CDAI) (r = -0.42), which did not reach statistical significance (p = 0.13), although the mean splanchnic transit time was reduced in the active group (4.0 s vs 6.9 s). The SMA flow rate was significantly greater in active disease (37 ml s(-1) vs 22 ml s(-1); Mann-Whitney U, p = 0.02). This study demonstrates the feasibility of using contrast-enhanced ultrasound as an assessment tool for Crohn's disease.

Bowel ultrasound in Crohn's disease: surgical perspective

BACKGROUND

Bowel ultrasound has been proven to be a useful tool in the management of Crohn's disease, particularly in the assessment of intra-abdominal complications, most of which require surgery.

MATERIALS AND METHODS

The National Library of Medicine has been searched for articles on the use of bowel ultrasound in Crohn's disease focusing on aspects of interest to the surgeon.

RESULTS AND CONCLUSIONS

Several studies have demonstrated that bowel ultrasound may be useful to reduce the risk of unnecessary laparotomy in patients presenting acute abdomen with suspected chronic inflammatory bowel disease. Bowel ultrasound has been proven to be of value in the follow-up of Crohn's disease patients since allowing early diagnosis of intra-abdominal complications and, therefore, optimising the diagnostic and surgical approach. At followup, bowel ultrasound may accurately diagnose early postoperative complications and long-term disease recurrence. In patients submitted to conservative surgery, ultrasonography reveals changes in diseased bowel walls that may be predictive of recurrence of the disease, and hence determinant in the choice of medical treatment.

Imaging of the small bowel in Crohn's disease: A review of old and new techniques

The investigation of small bowel morphology is often mandatory in many patients with Crohn’s disease. Traditional radiological techniques (small bowel enteroclysis and small bowel follow-through) have long been the only suitable methods for this purpose. In recent years, several alternative imaging techniques have been proposed. To review the most recent advances in imaging studies of the small bowel, with particular reference to their possible application in Crohn’s disease, we conducted a complete review of the most important studies in which traditional and newer imaging methods were performed and compared in patients with Crohn’s disease. Several radiological and endoscopic techniques are now available for the study of the small bowel; each of them is characterized by a distinct profile of favourable and unfavourable features. In some cases, they may also be used as complementary rather than alternative techniques. In everyday practice, the choice of the technique to be used stands upon its availability and a careful evaluation of diagnostic accuracy, clinical usefulness, safety and cost. The recent development of innovative imaging techniques has opened a new and exciting area in the exploration of the small bowel in Crohn’s disease patients.

Bowel ultrasound in Crohn's disease

Most published studies have found bowel ultrasound to be a useful tool in the management of Crohn's disease. Indeed, it has been successfully used as the imaging technique of choice in screening patients with clinically suspected Crohn's disease. In these patients, bowel ultrasound, which is well accepted by patients, non-invasive and of low cost, may be the first diagnostic tool employed for young patients and can be used in the preliminary diagnostic work-up prior to further invasive tests. The most important application of bowel ultrasound is, however, in the follow-up of patients already diagnosed with Crohn's disease, in whom it may be useful to assess the site and extent of the lesions and to ensure the early detection of intra-abdominal complications, particularly abscesses and strictures. In this regard, improving the ultrasound assessment of intramural blood flow by means of colour power-Doppler ultrasonography and intravenous contrast agents may help to differentiate fibrotic and inflammatory strictures, and to discriminate inflammatory masses from intra-abdominal abscesses. Despite several attempts to correlate ultrasound findings with clinical and biochemical activity, there are as yet no convincing data on the usefulness of ultrasound in assessing the activity of Crohn's disease. In contrast, preliminary results are in agreement regarding the usefulness of ultrasound in the assessment of postoperative recurrence and in monitoring the outcome of the disease following surgery. In fact, the persistence of a thickened bowel wall or increased high bowel wall thickening at ultrasound following surgery has been identified as an index of early surgical recurrence. How these data may be usefully employed in the management of individuals with Crohn's disease needs to be investigated in further studies.

Targeting mucosal addressin cellular adhesion molecule (MAdCAM)-1 to noninvasively image experimental Crohn's disease

BACKGROUND & AIMS

Inflammatory bowel disease (IBD) is the second most common chronic inflammatory disorder worldwide; however, a noninvasive means of accurately assessing the severity and extent of intestinal inflammation is currently not available. The aim of the present study was to develop a noninvasive imaging modality to detect and evaluate ileitis in SAMP1/YitFc (SAMP) mice.

METHODS

An image-enhancing ultrasound (US) contrast agent, consisting of encapsulated gaseous microbubbles (MB), was developed specifically to bind mucosal addressin cellular adhesion molecule-1 (MAdCAM-1), a mucosal-restricted addressin up-regulated during gut inflammation. MAdCAM-1-targeted MB (MB(M)) were tested for binding specificity on MAdCAM-1 protein and tumor necrosis factor (TNF)-stimulated SVEC4-10 endothelial cells using an in vitro flow chamber assay and for their ability to detect and quantify ileitis by intravital microscopy and transabdominal US.

RESULTS

Under in vitro flow conditions, a 100-fold increase in MB(M) binding was observed on MAdCAM-1 protein compared with nonspecific MB (P < .001). TNF-stimulated endothelial cells bound significantly more MB(M) vs nonspecific MB (P < .001), which was abrogated after preincubation with anti-MAdCAM-1 antibodies (P < .001). In vivo, MB(M) specifically accumulated in focal areas of ileal inflammation and produced stronger acoustic echoes, measured by average video intensity, in SAMP vs uninflamed AKR mice (P < .001) or SAMP given nonspecific MB (P < .001). MB(M)-specific video intensity showed a strong positive correlation with total ileal inflammatory scores (R2 = 0.92).

CONCLUSIONS

We have developed a novel intravascular US contrast agent targeting MAdCAM-1 that specifically detects and quantifies intestinal inflammation in experimental ileitis, providing the potential for a reliable, noninvasive means to diagnose and monitor disease in patients with IBD.

Role of US in detection of Crohn disease: meta-analysis

PURPOSE

To evaluate the accuracy of ultrasonography (US) in the detection of Crohn disease in adults by systematically reviewing both cohort studies (those including patients whose clinical characteristics were consistent with those caused by an inflammatory bowel disease) and case-control studies (those in which patients with Crohn disease were compared with patients with other bowel diseases or healthy control subjects).

MATERIALS AND METHODS

The MEDLINE, EMBASE, and Cochrane Library databases were used to retrieve all the cross-sectional studies that assessed the diagnostic accuracy of US against that of one of several predefined reference standards (ie, radiologic, endoscopic, or histologic findings). The studies that fulfilled the inclusion criteria were identified, and their methodological quality was evaluated. Of the 2860 primary studies identified, two case-control and five cohort series fulfilled the inclusion criteria. Statistical analysis was performed by using the summary receiver operating characteristic (SROC) model.

RESULTS

The ranges of US sensitivity and specificity for the diagnosis of Crohn disease reported for the included series were 75%-94% and 67%-100%, respectively; the heterogeneity of these values prevented the calculation of a cumulative value. The SROC curve revealed a clear cutoff effect that depended on the chosen bowel wall thickness threshold. Sensitivity and specificity of 88% and 93%, respectively, were achieved when a bowel wall thickness threshold greater than 3 mm was used, and sensitivity and specificity of 75% and 97%, respectively, were achieved when a threshold greater than 4 mm was used.

CONCLUSION

US examination seems appropriate for confirming or excluding Crohn disease as a diagnosis in a clinical context characterized by a pretest probability of Crohn disease that ranges from 12% to about 60%. In particular, for Crohn disease limited to the ileum, US may represent a valid alternative to the small-bowel series, while for colonic involvement US may be useful in ruling out the diagnosis.

Modern imaging of Crohn's disease using bowel ultrasound

Technological advancement of ultrasound (US) equipments and understanding of bowel appearances with high resolution US during the last decade has led to consideration of this imaging procedure as an important tool for inflammatory bowel diseases assessment. In particular, Crohn's disease (CD) for its pathologic characteristics (that is, inflammatory infiltration of the entire bowel wall with possible extension to the surrounding mesentery) is the disease entity which has mainly taken advantage from this non-invasive, radiation-free technique. Beside correctly defining anatomic location and extension of CD lesions within the bowel in the majority of cases, US also shows perigut abnormalities and may demonstrate complications such as fistulas and abscesses. With the help of Power Doppler function, some additional information may be obtained about the local activity of the disease which is particularly useful in the presence of strictures. New US technologies (such as those using intravenous bolus contrast agents or oral nonabsorbable anechoic solutions) may further improve diagnostic capability of US in this context, thus probably revolutioning the diagnostic approach to this disease in the near future, particularly during follow-up in CD of the small bowel.

Clinical relevance of transabdominal ultrasonography and magnetic resonance imaging in patients with inflammatory bowel disease of the terminal ileum and large bowel

BACKGROUND

Ileocolonoscopy represents the diagnostic standard in the work-up of patients with inflammatory bowel diseases (IBD). Patients are often reluctant to be colonoscoped because of the invasiveness and pain sensation during colonoscopy.

AIMS

To compare the usefulness oftransabdominal ultrasound (US) and magnetic resonance imaging (MRI) in assessing disease extension and activity in patients with IBD restricted to the terminal ileum and large bowel.

PATIENTS AND METHODS

61 patients with IBD [37 Crohn's disease (CD) and 24 ulcerative colitis (UC)] were prospectively studied. All patients underwent clinical and laboratory assessment, ileocolonoscopy, transabdominal sonography, and MRI within 5 days. Involved bowel segments were defined as those with bowel wall thickness >3 mm and increased Doppler signal on US or contrast enhancement of the bowel wall on MRI. To compare disease activity endoscopic, MRI and US findings were graded with newly developed scores.

RESULTS

The segment-by-segment analysis revealed an overall accuracy of 89% for US and 73% for MRI in identifying active IBD. The accuracy was better in patients with UC than in patients with CD for both US and MRI. The endoscopic activity index (EAI) correlated stronger with the US activity index (r = 0.884) than with the MRI activity index (r = 0.344). The correlation of US and MRI activity indices with EAI was better in patients with UC compared with patients with CD. All three imaging methods showed a significant correlation with clinical disease activity in patients with UC but not in patients with CD.

CONCLUSION

This study provides strong evidence that US should be considered as a first-choice method for follow-up of patients with IBD of the terminal ileum and large bowel.

Detection of ileocecal Crohn's disease using ultrasound as the primary imaging modality

At our hospital ultrasound (US) is used as an initial screening procedure in all patients with abdominal symptoms. The purpose of this study was to assess the effect of this policy on the detection of ileocecal Crohn's disease. We retrospectively studied all patients with a new diagnosis of ileocecal Crohn's disease from our institute over the period 1990-2001. The final diagnosis was based on clinical follow-up and pathological, surgical, US, and other radiological findings. We noted who referred the patient to the radiology department, what the initial clinical presumption was, and what the first imaging study was. US diagnoses were determined from the initial US report and US findings were registered from the images. There were a total of 47 patients (20 men, 27 women) with a mean age of 30 years and a median age of 27 years (range 14-75 years). In all patients the initial imaging study was an abdominal US. Using US, a confident diagnosis of ileocecal Crohn's disease was made in 35 of the 47 patients, Crohn's disease was suggested among the differential diagnosis in 10, and an incorrect diagnosis was made in 2 patients. In 28 of 47 patients, the referring physician did not consider Crohn's disease when requesting the initial US examination. In eight patients with appendicitis-like symptoms, the US findings strongly influenced the decision to refrain from operation at that point in time. US, when used as a low-threshold diagnostic procedure, is a reliable and noninvasive means for making an early diagnosis of ileocecal Crohn's disease in patients who present with atypical symptoms. It may prevent both unnecessary therapeutic delay as well as unnecessary surgery.

Abdominal pain and bowel dysfunction: diagnostic role of intestinal ultrasound

BACKGROUND

Abdominal pain and irregular bowel habits are common among young people. Irritable bowel syndrome is frequent in the general population and has important economic and social costs. Inflammatory bowel diseases are chronic processes with an acute or indolent onset in young people. Differential clinical diagnosis between irritable bowel syndrome and inflammatory bowel disease can be difficult since symptoms and signs are often non-specific.

OBJECTIVE

To evaluate the role of intestinal ultrasound, a non-invasive, simple and cheap diagnostic tool, in the differentiation between organic and functional bowel diseases.

METHODS

Abdominal and intestinal ultrasound examinations were performed on 313 consecutive outpatients presenting with abdominal pain and irregular bowel habits lasting more than 3 months. These patients had no symptoms or signs indicative of organic disorders and no previous diagnosis of organic disease. An intestinal wall thickness of more than 7 mm was considered diagnostic for inflammatory bowel disease. Subsequently, we compared the ultrasound results with diagnoses obtained following the traditional criteria (radiological and endoscopic examinations).

RESULTS

Intestinal ultrasound for the diagnosis of inflammatory bowel disease showed 74% sensitivity, 98% specificity, a positive predictive value of 92% and a negative predictive value of 92%.

CONCLUSIONS

In our experience, intestinal ultrasound seems important as a first diagnostic tool in young patients without clear symptoms or signs of organic diseases, and can be used as an indication that subsequent invasive tests are required.

Hydrocolonic sonography for evaluating inflammatory bowel disease

OBJECTIVE

The purpose of our study was to compare the usefulness of hydrocolonic sonography and (99m)Tc-hexamethylpropyleneamine oxime (HMPAO)--labeled leukocyte scintigraphy in the examination of patients with inflammatory bowel disease, using precise sonographic criteria of bowel involvement.

SUBJECTS AND METHODS

Sixty-eight consecutive patients with active inflammatory bowel disease (34 ulcerative colitis and 34 Crohn's disease), 12 with inactive inflammatory bowel disease, and 10 control subjects were prospectively studied. Patients with active disease underwent clinical assessment, hydrocolonic sonography, scintigraphy, and colonoscopy within 72 hr, whereas patients with inactive disease and control subjects underwent clinical examination and hydrocolonic sonography.

RESULTS

Involvement of a colonic segment by active inflammatory bowel disease was best defined by mucosal thickness greater than 1.5 mm, bowel wall thickness greater than 4 mm, mucosal irregularity, or the absence of haustra; and involvement of the terminal ileum by bowel wall thickness greater than 4 mm. Using these criteria, hydrocolonic sonography had 100% sensitivity for identifying patients with active inflammatory bowel disease and a greater overall accuracy (87%) than scintigraphy (77%) in the assessment of disease extension. In addition, strong correlation was shown between a hydrocolonic sonography activity index and clinical and endoscopic activity indexes.

CONCLUSION

This prospective study provides precise sonographic criteria for the definition of bowel involvement by active inflammatory bowel disease. Hydrocolonic sonography has a greater accuracy than scintigraphy for assessing disease extension and activity. Therefore, hydrocolonic sonography should be considered a first-choice technique to complete the study of inflammatory bowel disease after confirmation of the diagnosis by histology.

Small intestine contrast ultrasonography (SICUS) in the diagnosis of small intestine lesions

After the ingestion of iso-osmolar polyethylene glycol solution, the small bowel can be visualized on ultrasonography. The aim of this study was to assess sensitivity and specificity of SICUS in diagnosis of small bowel lesions. A total of 53 consecutive patients with suspected intestinal pathology underwent a diagnostic workup, including a small bowel follow-through and SICUS performed by independent operators. The sonologist was unaware of the clinical data. Diagnostic sensitivity and specificity were assessed using radiologic findings. Diagnostic sensitivity of SICUS was 100%, with a specificity of 97%. The concordance index was 0.956 (p < 0.003, kappa statistics) and the conformity between SICUS and radiology was 1. The diagnostic accuracy of SICUS to detect small bowel lesions is comparable to that of small bowel follow-through. Results of this study support the use of noninvasive, widely available, inexpensive, and nondemanding SICUS as an initial investigation in patients with suspected small bowel disease.

Transabdominal ultrasonography of the small bowel after oral administration of a non-absorbable anechoic solution: comparison with barium enteroclysis

AIM

The aim of this study was to determine if oral administration of a non-absorbable anechoic solution conveys any benefit during abdominal ultrasound (US), with special reference to its accuracy.

MATERIALS AND METHODS

Fifty-three adult out-patients scheduled for small bowel barium enema (SBE) were included. The day before SBE all patients underwent abdominal US before and after oral administration of an isotonic non-absorbable electrolyte solution containing polyethylene glycol (PEG-ELS). Sensitivity and specificity were evaluated using SBE as a gold standard.

RESULTS

After ingestion of PEG-ELS satisfactory distension of the intestinal lumen was obtained (11-25 mm) with sequential visualization of jejunoileal loops in 30.9 +/- 17.3 min. In 15 out of 53 cases both US and SBE showed bowel changes characteristic of Crohn's disease. In three out of 53 cases both US and SBE showed neoplasms. In one out of 53 cases US was negative, SBE positive for local nodularity and ulcerations typical of Crohn's disease. In one out of 53 cases US was negative, SBE positive for macronodularity consistent with coeliac disease. In five out of 53 cases US was negative, while SBE was positive for mininodularity expressive of lymphoid hyperplasia. In 28 out of 53 cases both examinations were negative.

CONCLUSION

PEG-ELS administration allows a thorough US investigation of the small bowel, with fair sensitivity (72%) and excellent specificity (100%). False negative findings are mainly due to lymphoid hyperplasia, a feature of uncertain significance in adults.

Contrast ultrasonography of the normal small bowel

In basal conditions, the small bowel loops cannot be properly visualized by means of real-time ultrasound (US). Aims of this study were: 1. to assess whether an isosmolar solution containing a nondigestable, nonabsorbable and nonfermentable hydrophilic macro molecule, such as polyethylene glycol (PEG), can be profitably used as a contrast agent to visualize the entire small intestine with US (small intestine contrast ultrasonography, SICUS); and 2. to define the normal US values of wall thickness and luminal diameter of the jejunum, ileum and terminal ileum. Real-time ultrasonography was performed in 10 healthy volunteers with 4-and 5-MHz linear-array transducers in basal fasting conditions and after ingestion of an isosmolar PEG solution. In basal fasting conditions, only a few segments of jejunum and/or ileum could be visualized in some of the investigated subjects. After ingestion of the contrast solution, the entire small bowel could be visualized in any single subject. A contrast sonography of the entire small bowel could be satisfactorily performed with 200 mL-820 mL of contrast solution in a time period that did not exceed 65 min. Luminal diameter at the level of the jejunum (19 +/- 2.3 mm) and proximal ileum (18 +/- 1.8 mm) was significantly greater (p < 0.01) than at the level of distal ileum (16.4 +/- 2.8 mm). Wall thickness was greater at the level of the terminal ileum (2 +/- 0.4 mm) than of the jejunum (1.6 +/- 0.5 mm) but the difference did not reach statistical significance. Details such as valvulae conniventes and multilayered structure of the wall could be recognized. In conclusion, after the ingestion of an isosmolar PEG electrolyte balanced solution, it is possible to visualize with ultrasonography the entire small intestine and to measure wall thickness and luminal diameter of the jejunum, the ileum and the terminal ileum. Such a noninvasive, inexpensive method can be used to investigate the morphological aspects of the small bowel.

Transabdominal bowel sonography for the detection of intestinal complications in Crohn's disease

BACKGROUND

The course of Crohn's disease is characterised by the occurrence of intestinal complications such as strictures, intra-abdominal fistulas, or abscesses. Standard diagnostic procedures may fail to show these complications, in particular fistulas.

AIMS

To test the value of transabdominal bowel sonography (T) for the detection of intestinal complications in Crohn's disease.

METHODS

T was prospectively performed in 213 patients with Crohn's disease in a university based inflammatory bowel disease referral centre. Thirty three underwent resective bowel surgery and were included in this study. The accuracy of T to detect strictures, intra-abdominal fistulas, or abscesses was compared with surgical and pathological findings.

RESULTS

T was able to identify strictures in 22/22 patients and to exclude it in 10/11 patients (100% sensitivity, 91% specificity). Fistulas were correctly identified in 20/23 patients and excluded in 9/10 patients (87% sensitivity, 90% specificity). Intra-abdominal abscesses were correctly detected in 9/9 patients and excluded in 22/24 patients (100% sensitivity, 92% specificity).

CONCLUSIONS

In experienced hands T is an accurate method for the detection of intestinal complications in Crohn's disease. T is thus recommended as a primary investigative method for evaluation of severe Crohn's disease.

Ultrasonographic detection of intestinal complications in Crohn's disease

The aim of this study was to evaluate the sensitivity and specificity of ultrasound (US) in assessing the main abdominal complications of Crohn's disease (CD), such as strictures, fistulas and abscesses. A series of 98 consecutive inpatients with complicated and uncomplicated Crohn's disease, having undergone a complete endoscopic and radiographic evaluation of the intestinal tract, entered the study. In particular, in these patients the presence of strictures, fistulas, and abscesses, detected by means of colonoscopy, small bowel x-ray, double-contrast barium enema, and computed tomography, was also assessed by means of transabdominal US. US sensitivity and specificity in the assessment of stenosis of Crohn's disease were 74.4% and 93.1%, respectively. When ileal and colonic stenosis were considered separately, transabdominal US correctly assessed 84.6% of ileal stenosis and 58.8% of colonic stenosis. Eight of 12 fistulas were detected, but only 50% of enteroenteric fistulas were diagnosed. The presence of abscesses was correctly detected in 83.3% of cases by means of US. Our data suggest that US is a suitable complementary method for the detection of abdominal complications of Crohn's disease, such as strictures and abscesses; however, its usefulness in assessing enteroenteric fistulas seems to be fairly limited.

Ultrasonography as a primary diagnostic tool in patients with inflammatory disease and tumors of the small intestine and large bowel

In 240 patients with predefined indications, the validity of ultrasound imaging as a primary diagnostic procedure was examined prospectively. Ultrasonography revealed normal intestinal findings in 150 patients and pathological lesions in 90 subjects. All patients underwent subsequent endoscopic, radiological, or surgical examination. In 7 patients with Crohn's disease and in 2 patients with radiation colitis, the ultrasound findings were false-negative. In the other 9 cases, ultrasonography suggested false-positive results. Ultrasonographic examination of the small intestine and large bowel had a very high overall validity, with a sensitivity of 90% and specificity of 94%.

A case of Crohn's disease limited to the appendix, showing a portentous ultrasonographic finding

A case of Crohn's disease limited to the appendix is reported. A preoperative ultrasonic study of the lower right abdomen revealed an interesting appearance that we named the "milky way sign." Microscopic findings in the resected specimen confirmed that the sign represented adipose tissue of the mesoappendix that had become involved by transmural inflammation. This seems to be highly suggestive of Crohn's disease.

Transabdominal ultrasonography as the primary investigation in patients with suspected Crohn's disease or recurrence: a prospective study

Traditionally, patients with suspected or known and possible recurrent Crohn's disease have been investigated by small bowel barium radiology, which incurs a relatively high radiation dose. Despite patient selection a significant number have a normal barium examination. A prospective study was performed to evaluate the use of transabdominal ultrasound as the initial investigation in these two groups. One hundred and twenty-seven patients were examined, including 31 with a previous history of Crohn's disease. In the known Crohn's disease group there were 14 true positive ultrasound examinations and eight true negative, with six false positive and three false negative examinations. In the 96 patients not previously known to have Crohn's disease, there were 18 true positive and 70 true negative examinations, with two false positive and six false negative examinations. The overall sensitivity for ultrasound was 78% with a specificity of 91%. A significant learning curve was apparent in the early stages of study; in the last 64 patients the sensitivity was increased to 87%. These data support the use of ultrasound as the initial investigation in patients with suspected Crohn's disease or recurrence, prior to consideration for small bowel barium radiology, to reduce the large number of unnecessary small bowel barium examinations currently being performed.

Comparison of scintigraphy with indium-111 leukocyte scan and ultrasonography in assessment of X-ray-demonstrated lesions of Crohn's disease

The aim of this study was to compare the results obtained with an indium-111 scan with those obtained with less expensive and harmless ultrasonography to evaluate the location and inflammatory activity of Crohn's disease. Thirty-one patients previously studied with x-ray underwent abdominal 111In scans and ultrasonography (US). Sensitivity and specificity of US in detecting lesions seen with 111In scan were 77% and 92.8%, respectively. Sensitivity and specificity of 111In scan in detecting x-ray-defined lesions were 69.2% and 92.7%; the figures for US were 73% and 93.3%, respectively. Considering the evaluation of disease activity, ultrasonographic bowel wall thickness was significantly related to scintigraphic intensity of emission (r = 0.75 P < 0.01). Our experience suggests that US provided information about the location and inflammatory activity of lesions similar to that obtained from 111In scan.

Detection of liver involvement in inflammatory bowel disease by abdominal ultrasound scan

Fifty patients with ulcerative colitis, 24 with Crohn's disease, and 50 controls were studied by liver function tests and abdominal ultrasound scan. Twenty-two percent of ulcerative colitis patients, 29% of Crohn's disease patients, and none of the controls showed abnormal liver function tests. All subjects with abnormal liver function tests also had changes in ultrasound liver scan, consisting of hepatomegaly and/or a dysechoic liver echo pattern. Furthermore, the same ultrasound changes were observed, in the absence of any liver function test abnormalities, in 58% of ulcerative colitis patients, 50% of Crohn's disease patients and 6% of controls (P less than 0.0005, inflammatory bowel disease versus controls). Overall, some evidence of liver involvement, as judged by abnormal liver tests and/or abnormal ultrasound liver scan, was detected in about 80% of inflammatory bowel disease patients. Six patients with minor abnormalities of liver function tests underwent liver biopsy and 5 of them had pericholangitis. Ultrasound liver scan may provide a useful tool to evaluate the occurrence of liver involvement in inflammatory bowel disease patients.

Ultrasonic patterns in inflammatory bowel disease

Ultrasound examination was performed in 90 patients with varying bowel pathology. Ultrasound reliably demonstrated thickening of the bowel. In addition, the pattern of abnormality seen in Crohn's disease and ulcerative colitis was different, and corresponded to the pathological changes seen in these disease processes. The pattern of bowel abnormality seen in other bowel diseases with an inflammatory aetiology generally corresponded to either the Crohn's or ulcerative colitic pattern. The appearances are described, together with findings in other non-neoplastic diseases of the bowel.

The value of dynamic ultrasound scanning in Crohn's disease

In a prospective, blinded study we investigated 30 patients with Crohn's disease (CD) and 27 normal controls by means of dynamic grey-scale ultrasound scan. Within a few weeks the patients were also examined by radiography of the small bowel. Of the 30 patients, 21 had CD lesion of the small bowel as judged by radiography. A target lesion at the ultrasound scan indicating thickened bowel wall was seen in 15 CD patients, of which 14 showed radiographic signs of CD in the ileum and/or right side of the large bowel, whereas one had normal radiographic findings. Seven patients out of 15 without sonographic changes had radiographic signs of CD. The patients with discrepancy between the two examinations could not be clinically characterized as an entity. None of the 27 normal controls showed signs of intestinal disease at the ultrasound examination. We conclude that dynamic grey-scale ultrasound examination is a new tool in depicting the CD lesion, but it does not seem to be able to replace the radiographic examination. However, it may find a place in the follow-up study of patients with known CD, thereby avoiding repeated radiographic examinations. Furthermore, the possibility of diagnosing abscesses and fistulae by sonography is well known and has relevance in CD.

Transrectal ultrasonography: interpretation of normal intestinal wall structure for the preoperative staging of rectal cancer

An in vitro ultrasonographic study was carried out to four polyethylene membranes of different thicknesses and on four normal surgical specimens from the rectal wall, to assess its various layers and their anatomical structure. Three different techniques were used, and an electronic equipment measured the thickness of the membranes and of the surgical specimens. Polyethylene membranes less than 1000 microns thick gave linear echoes; the 1000-microns-thick membrane gave a three-layer image--two hyperechogenic layers separated by a hypoechogenic one. The rectal wall was separated into the mucosa-submucosa and the muscularis propria-serosa or muscularis propria (in the extraperitoneal rectum); their thickness ranged from 900 to 1000 microns and from 1500 to 8000 microns, respectively. Even though the mucosa-submucosa, the muscularis propria-serosa, and the muscularis propria each gave a three-layer ultrasonographic image (hyper-hypo-hyper), the resulting image of the entire rectal wall was of five layers (hyper-hypo-hyper-hypo-hyper). Transrectal scan carried out on 20 control patients confirmed the results obtained in vitro, even though at times it was difficult to detect clearly the fifth layer. Interpretation of the five layers was as follows: the second and fourth corresponded to the mucosa-submucosa and muscularis propria, respectively; the first, third, and fifth were considered to reflect interfaces originating from different acoustic impedance structures. The fourth layer was always thicker than the second one. There was no difference between intra- and extra-peritoneal images. A further study carried out on nine patients with rectal cancer by transrectal ultrasonography proved the reliability of this method in assessing the cancer infiltration of the wall and its importance in the preoperative staging of rectal cancer.

Real-time ultrasound in Crohn's disease: characteristic features and clinical implications

Thirty-two children with Crohn's disease were evaluated by real-time ultrasonography. The typical pattern of Crohn's disease caused by bowel wall thickening is the "bull's eye phenomenon", the elongated tubular stiff bowel loop with narrowing of the lumen and the small bowel conglomerate tumor. In indefinable abdominal complaints sonography may lead to the correct diagnosis. The differential diagnosis of similar sonographic features and the limitations of ultrasound in gastrointestinal disease must be considered. In proven Crohn's disease the findings in follow-up match the clinical course and may delineate complications, such as ileus, abscess, hydronephrosis, gallstones or involvement of parenchymal organs, as seen in 15 patients. Thus ultrasound will restrict repeated x-ray studies and support patient management.

The "hay-fork" sign in the ultrasonographic diagnosis of intussusception

Ultrasonography was used to evaluate a palpable abdominal mass in a woman. The characteristic "hay-fork" image led to the correct diagnosis of colocolic intussusception, which had not been suspected. This sign appears to be highly specific for intussusception.

Ultrasonography in Crohn's disease

Eighteen patients with acute and subacute Crohn's disease were examined by ultrasound. In 7, ultrasound was the initial screening procedure leading to the diagnosis of Crohn's disease. This diagnosis was subsequently proved by results of barium studies. The most frequent ultrasonographic finding was conglomeration: an irregular mass containing scattered echodense and sonolucent areas that represented matted inflamed bowel loops. Some of the conglomerations showed a fine diffuse echo pattern with ill-defined posterior borders due to poor transmission. These areas denoted mesenteric fat covering the matted loops (fatty conglomeration). Other ultrasonographic findings were the "target" or "bull's eye" sign, abscess formation, and fluid in the cul-de-sac.

Ultrasound demonstration of bowel wall thickness in inflammatory bowel disease

Twenty-eight patients with inflammatory bowel disease were examined with ultrasound. When possible, maximum bowel wall thickness was measured and the site of any focal abnormality recorded. There were 19 patients with Crohn's disease and nine with ulcerative colitis. Bowel wall thickness ranged from 0.5-1.8 mm in the Crohn's group to 0.3-0.8 cm in the ulcerative colitis group. Following treatment, a measurable reduction in bowel wall thickness was demonstrated in 13 of the patients with Crohn's disease. No significant change in bowel wall thickness was detected in five of the patients with ulcerative colitis. The results echo the findings at double-contrast radiography and suggest a possible role for ultrasound in the assessment and follow-up of inflammatory bowel disease.

Ultrasonography of the cecum

Ultrasound can define masses in the cecum and the cecal bed. In the patient with a prior resection of adenocarcinoma of the cecum, the sonogram fulfills a primary role in the detection of large and ill-defined recurrences not amenable to detection by barium enema because of a right colectomy. Discrete lesions within the cecum whether secondary to inflammatory or neoplastic processes could not be differentiated.

Dynamic imaging of the stomach by real-time ultrasound--a method for the study of gastric motility

The use of real-time ultrasonic imaging of the stomach for the study of gastric contractions in response to a liquid test meal is described. Gastric contractions in the pyloric antrum and distal body of the stomach were observed on closed circuit television, recorded on to cassette tape and also imaged on polaroid and ciné film. Gastric contractions were recorded from the pyloric antrum by longitudinal scanning in the lower epigastrium and reproducible motility tracings were obtained on a fibreoptic chart recorded. Intravenous metoclopramide enhanced the magnitude and frequency of antral movement, which was abolished by intravenous propantheline. Real-time ultrasonic imaging permits the non-invasive study of gastric contractions. It is safe, may be repeated as required, and provides a method for the study of the effect of drugs and disease states on gastric motility.