[Imaging diagnosis of inflammatory bowel disease]

The term "chronic inflammatory bowel disease" represents a spectrum of diseases out of which ulcerous colitis and Crohn's disease are the far most common. Large bowel enemas have lost their relevance compared to colonoscopy over the past years and small bowel enteroclysis has also been widely replaced by CT- and especially MR-enteroclysis meanwhile. The diagnostic value of computed tomography and MR-tomography in chronic inflammatory bowel disease is based on the excellent visualization and documentation of extent and severity of bowel wall inflammation, estimation of inflammatory activity of the disease and of detection of potential extraintestinal complications and/or additional diagnoses by these two methods. Nevertheless, conventional radiological techniques as well as sonography may still be valuable under certain conditions. Furthermore, nowadays imaging of chronic inflammatory bowel diseases includes also White Blood Cell scintigraphy as well as Positrone Emission Tomography which provide informations about extent and especially activity of the disease. The presented article provides an overview of the possibilities and limitations of the available imaging modalities in inflammatory bowel diseases and helps the reader to decide under what conditions which one of the available examinations should be regarded as the most appropriate and promising one.

CT of acute bowel ischemia

Bowel ischemia may be caused by many conditions and manifest with typical or atypical and specific or nonspecific clinical, laboratory, and radiologic findings. It may mimic various intestinal diseases and be confused with certain nonischemic conditions clinically and at computed tomography (CT). Bowel ischemia severity ranges from mild (generally transient superficial changes of intestinal mucosa) to more dangerous and potentially life-threatening transmural bowel wall necrosis. Causes of critically reduced blood flow to the bowel are diverse, ranging from occlusions of mesenteric arteries or veins to complicated bowel obstruction and overdistention. CT can demonstrate changes in ischemic bowel segments accurately, is often helpful in determining the primary cause of ischemia, and can demonstrate important coexistent findings or complications. Unfortunately, common CT findings in bowel ischemia are not specific, and specific findings are rather uncommon. Therefore, it often is a combination of nonspecific clinical, laboratory, and radiologic findings-especially detailed knowledge about the pathogenesis of acute bowel ischemia in different conditions-that helps most in correct interpretation of CT findings. To improve understanding of this complex heterogeneous entity, this article provides an overview of the anatomy and physiology of mesenteric perfusion and discussions of causes and pathogenesis of acute bowel ischemia, CT findings in various types of acute bowel ischemia, and potential pitfalls of CT.

Three-dimensional dynamic MR-hysterosalpingography; a new, low invasive, radiation-free and less painful radiological approach to female infertility

BACKGROUND

The purpose of this study was to propose a new method for imaging the uterine cavity and Fallopian tube patency by three-dimensional dynamic magnetic resonance hysterosalpingography (3D dMR-HSG) and to analyse if, by using a higher viscosity contrast solution, direct visualization of the Fallopian tubes may be achieved by this new technique.

METHODS

10 consecutive infertile women underwent 3D dMR-HSG and conventional HSG as gold standard. 3D dMR-HSG consisted of injection of 20 ml of a gadolinium-polyvidone solution into the uterine cavity while acquiring five consecutive three-dimensional (3D) T1-weighted MR-sequences.

RESULTS

In three patients the catheter became dislodged during 3D dMR-HSG. However, in one of these patients the examination was still partially diagnostic. Imaging findings of 3D dMR-HSG showed good correlation with conventional hysterosalpingography and allowed 3D imaging of the uterine cavity and of Fallopian tube patency in 8/10 patients and direct visualization of the Fallopian tubes in 5/7 patients.

CONCLUSION

3D dMR-HSG represents a new and promising imaging approach to female infertility causing less pain and avoiding exposure of the ovaries to ionizing radiation. By using a higher viscosity MR-contrast agent it allows not only visualization of uterine cavity and Fallopian tube patency but also direct visualization of Fallopian tubes.

"Cecal gangrene": a rare cause of right-sided inferior abdominal quadrant pain, fever, and leukocytosis

We report on a 58-year-old man with known diabetes, congestive heart failure, and need for chronic hemodialysis presenting with right lower abdominal quadrant pain, fever, and leukocytosis. Although initial clinical findings were highly suggestive of acute appendicitis, CT revealed marked circumferential wall thickening of the cecum, which was interpreted as cecal infarction by the radiologist. Intraoperatively, cecal necrosis was confirmed, but the ileocecal valve and, especially, the appendix showed no ischemia. No vascular occlusions were found. Histopathologic analysis of the resected cecum demonstrated isolated transmural cecal necrosis with marked infiltration of the cecal wall by numerous bacteria and neutrophils. We present the CT features and histopathologic findings of isolated cecal gangrene, review the pathogenesis of occlusive and nonocclusive cecal ischemia or infarction, and discuss the role of bacterial superinfection as a potential cofactor in the pathogenesis of isolated cecal necrosis which should be included in the differential diagnosis of right-sided inferior abdominal quadrant pain.

Flush symptoms caused by a mesenteric carcinoid without liver metastases

Flushing is a known symptom in intestinal carcinoid tumors which usually occurs only in the presence of liver metastases. A 62-year-old women presented with abdominal pain, nausea and flush symptoms. US, CT, octreotide scintigraphy and biopsy revealed a primary mesenteric carcinoid with retroperitoneal lymph node metastases and a solitary leftsided supraclavicular lymph node metastasis proving lymphatic spread over the thoracic duct, but liver metastases were excluded. This is a report on a mesenteric carcinoid which lead to flush symptoms despite absence of liver metastases, since retroperitoneal lymph node metastases enabled a direct hormone release into the systemic circulation.

Hepatic veno-occlusive disease: MRI findings

We present magnetic resonance imaging findings in a patient with proven hepatic veno-occlusive disease (VOD) caused by the use of "poppers," a recreational drug used during anal intercourse. Although this report emphasizes the differential magnetic resonance imaging features between VOD and Budd-Chiari syndrome, our case is unique because the VOD was induced by unrelated substances.

[Value of radiological imaging after laparoscopic gastric banding]

Over the past years "laparoscopic gastric banding" has evolved to one of the leading surgical techniques for the treatment of patients with morbid obesity. Mainly two systems are used worldwide; the "LAP BAND" (ASGB--Adjustable Silicone Gastric Banding) and the "Swedish Band" (SAGB--Swedish Adjustable Gastric Banding) which may both be implanted laparoscopically around the proximal stomach at a suprabursal position, about 2 cm distally to the cardia, with the intention to create a small pouch and, therefore, to provide an earlier satiation. Both systems show only minor differences regarding their consistency and their opacity as well as regarding the volume of the system. However, the working mechanisms and the principal techniques of surgical implantation, luminal adjustment and management of postoperative weight loss as well as the way how to perform radiological controls in these patients are quite similar in both systems. Although these patients might be managed postoperatively by the clinicians alone, it has become well accepted over the past years that radiological controls are not only important for an exact luminal adjustment but crucial for the management of an ideal postoperative weight loss and for the detection of various postoperative complications. This article describes the radiographic appearances of both systems, instructs how to perform postoperative radiological controls in these patients and provides an overview of the known postoperative complications together with some recommendations regarding their therapeutic approach.

CT findings in isolated ischemic proctosigmoiditis

The purpose of our study was to describe the CT features of ischemic proctosigmoiditis in correlation with clinical, laboratory, endoscopic, and histopathologic findings. Our study included seven patients with isolated ischemic proctosigmoiditis. Patients were identified by a retrospective review of all histopathologic records of colonoscopic biopsies performed during a time period of 4 years. All patients presented with left lower abdominal quadrant pain, bloody stools, and leukocytosis, and four patients had fever at the time of presentation. Four of seven patients suffered from diarrhea, one of seven was constipated and two of seven had normal stool consistency. The CT examinations were reviewed by two authors by consensus and compared with clinical and histopathologic results as well as with the initial CT diagnosis. The CT showed a wall thickening confined to the rectum and sigmoid colon in seven of seven patients, stranding of the pararectal fat in four of seven, and stranding of the perisigmoidal fat in one of seven patients. There were no enlarged lymph nodes, but five of seven patients showed coexistent diverticulosis and in three of these patients CT findings were initially misinterpreted as sigmoid diverticulitis. Endoscopies and histopathologic analyses of endoscopic biopsies confirmed non-transmural ischemic proctosigmoiditis in all patients. Isolated ischemic proctosigmoiditis often presents with unspecific CT features and potentially misleading clinical and laboratory findings. In an elderly patient or a patient with known cardiovascular risk factors the diagnosis of ischemic proctosigmoiditis should be considered when wall thickening confined to the rectum and sigmoid colon is seen that is associated with perirectal fat stranding.

Portal-venous gas unrelated to mesenteric ischemia

The aim of this study was to report on 8 patients with all different non-ischemic etiologies for portal-venous gas and to discuss this rare entity and its potentially misleading CT findings in context with a review of the literature. The CT examinations of eight patients who presented with intrahepatic portal-venous gas, unrelated to bowel ischemia or infarction, were reviewed and compared with their medical records with special emphasis on the pathogenesis and clinical impact of portal-venous gas caused by non-ischemic conditions. The etiologies for portal-venous gas included: abdominal trauma ( n=1); large gastric cancer ( n=1); prior gastroscopic biopsy ( n=1); prior hemicolectomy ( n=1); graft-vs-host reaction ( n=1); large paracolic abscess ( n=1); mesenteric recurrence of ovarian cancer superinfected with clostridium septicum ( n=1); and sepsis with Pseudomonas aeruginosa ( n=1). The clinical outcome of all patients was determined by their underlying disease and not negatively influenced by the presence of portal-venous gas. Although the presence of portal-venous gas usually raises the suspicion of bowel ischemia and/or intestinal necrosis, this CT finding may be related to a variety of non-ischemic etiologies and pathogeneses as well. The knowledge about these conditions may help to avoid misinterpretation of CT findings, inappropriate clinical uncertainty and unnecessary surgery in certain cases.

CT findings in eosinophilic enterocolitis with predominantly serosal and muscular bowel wall infiltration

A 44-year-old female presented with tenderness of her abdomen, vomiting, intestinal obstruction, hypoalbuminemia and blood eosinophilia. Gastroscopy was normal and colonoscopic biopsies showed only non-specific inflammation of the colonic mucosa and submucosa. CT revealed large amounts of ascites and bilateral pleural effusions but eosinophil counts in the ascites were normal. At CT the jejunum was dilated and showed marked prominence of the valvulae whereas the ileum and the colon presented with a diffuse and hypoattenuating bowel wall thickening. The bowel wall thickening was most pronounced in the colon which especially showed also an impressive thickening and hyperenhancement mainly of its outer bowel wall layers. Parasitic infection could be excluded as well as a specific allergic response. In context with the known blood eosinophilia the diagnosis of an eosinophilic enterocolitis was suspected already by CT but finally only surgical full thickness biopsies could confirm the rare diagnosis of an eosinophilic enterocolitis with predominantly serosal and muscular bowel wall infiltration.

Swallowing abnormalities in multiple sclerosis: correlation between videofluoroscopy and subjective symptoms

The purpose of this study was to evaluate if subjective symptoms indicating an impaired deglutition correlate with videofluoroscopic findings in patients with multiple sclerosis (MS). Videofluoroscopic examinations of 18 MS patients were analyzed by a radiologist and a logopedist and compared with the symptoms of these patients. Four patients complained about permanent dysphagia. Six patients reported mild and intermittent difficulties in swallowing, but were asymptomatic at the time of videofluoroscopy. Eight patients had no symptoms regarding their deglutition. All patients ( n=4) who complained of permanent dysphagia showed aspiration. All patients ( n=6) with mild and intermittent difficulties in swallowing showed undercoating of the epiglottis and/or laryngeal penetration. Of those 8 patients without any swallowing symptoms, only 2 had a normal videofluoroscopy. Swallowing abnormalities seem to be much more frequent in patients with MS than generally believed and they may easily be missed clinically as long as the patients do not aspirate.

Pseudotumor of the pancreatic head associated with idiopathic retroperitoneal fibrosis

A 68-year-old male presented with abdominal pain and obstructive jaundice. CT revealed a large mass in the pancreatic head that was initially interpreted as pancreatic carcinoma. Needle biopsy revealed only fibrous tissue with signs of chronic inflammation. Together with typical findings of an idiopathic retroperitoneal fibrosis, the final diagnosis of multifocal idiopathic fibrosclerosis with focal pseudotumorous pancreatic head fibrosis could be made.

Multifocal inflammatory pseudotumor of the liver: dynamic gadolinium-enhanced, ferumoxides-enhanced, and mangafodipir trisodium-enhanced MR imaging findings

The MRI characteristics of a multifocal inflammatory pseudotumor of the liver are described. Emphasis is placed on the appearances following intravenous administration of both non-specific and liver-specific MR contrast agents. On post-gadolinium gradient-echo (GE) images an early, intense, and peripheral enhancement was followed by a homogeneous, complete, and persistent enhancement. Lesions showed no uptake following administration of ferumoxides particles nor mangafodipir trisodium, respectively. During follow-up, a peripheral hyperintense rim appeared on precontrast T1-weighted images, a feature not previously described.

Three-dimensional dynamic MR hysterosalpingography: a preliminary report

The aim of this study was to evaluate the feasibility of three-dimensional dynamic MR hysterosalpingography (3D MR HSG) for visualization of the cavum uteri and demonstration of bilateral fallopian tube patency as an alternative to conventional hysterosalpingography. Five infertile female patients underwent 3D dynamic MR HSG prior to conventional hysterosalpingography. The MR protocol consisted of axial T1-weighted spin-echo (SE), axial/coronal T2-weighted fast SE (FSE), and 3D MR angiography sequences before, during, and after injection of a diluted gadolinium solution into the cavum uteri via a balloon catheter. Positioning of the catheter was feasible in all patients. In one patient the catheter slipped out during MRI and in one patient the catheter was placed far in the cavum uteri. In three patients catheter position was optimal at the level of the cervical canal. Evaluation of pelvic anatomy, myometrium, and ovaries was possible in all patients on the basis of T1-weighted SE and T2-weighted FSE. Three-dimensional visualization of the dilated cavum uteri was possible in four patients. In these four patients 3D MR HSG also proved bilateral fallopian tube patency which was confirmed in each patient by conventional hysterosalpingography. Three-dimensional MR HSG is feasible and further research should be done to determine if this technique can evolve into an alternative technique to conventional hysterosalpingography with the advantages of no radiation and additional visualization of the uterus wall and ovaries.

Acute appendicitis in a young adult with midgut malrotation: a case report

Midgut malrotation is defined as a developmental anomaly that may cause atypical clinical symptoms in relatively common intestinal disorders due to altered anatomy. A 27-year-old woman presented with acute left-sided abdominal pain. Underlying type Ia malrotation prevented the correct clinical diagnosis of perforated, ulcerated appendicitis. Cross-sectional imaging demonstrated all the typical signs of this type of malrotation, i.e., right-sided duodenojejunal junction, left positioned cecum and ascending colon, inverted position of the superior mesenteric vessels, and hypoplasia of the uncinate process of pancreas, and surgical treatment was initiated.

Normal colonic wall thickness at CT and its relation to colonic distension

PURPOSE

The purpose of this work was to analyze the relation between normal colonic wall thickness at CT and local colonic distension.

METHOD

One hundred consecutively acquired patients were included in our study. All patients were asymptomatic regarding their intestine, and their history was always negative for intestinal disease. All CT examinations were performed for other reasons than intestinal disease. Colonic wall thickness at CT was measured digitally in every patient at four locations and set in relation to the local colonic distension.

RESULTS

The normal colonic wall thickness ranged from 0 to 2 mm in colonic segments with a diameter of >/=4-6 cm, from 0.2 to 2.5 mm in colonic segments with a diameter of 3-4 cm, from 0.3 to 4 mm in colonic segments with a diameter of 2-3 cm, and from 0.5 to 5 mm in colonic segments with a diameter of 1-2 cm. Maximal colonic wall thickness ranged up to 6 and 8 mm in the proximal and distal colon, respectively, if the measured colonic segment showed a luminal width of <1 cm according to contraction.

DISCUSSION

The normal colonic wall thickness at CT should be regarded as a dynamic value that stays in clear relation to the local colonic distension. In contracted colonic segments, a colonic wall thickness of 6-8 mm may still be normal. On the other hand, a colonic wall measuring 5 and 3 mm should be regarded as thickened if found in colonic segments with a luminal width of >2 and 4 cm, respectively.

Pneumatosis intestinalis and portomesenteric venous gas in intestinal ischemia: correlation of CT findings with severity of ischemia and clinical outcome

OBJECTIVE

The purpose of this study was to analyze the correlation between pneumatosis or portomesenteric venous gas, or both, the severity of mural involvement, and the clinical outcome in patients with small- or large-bowel ischemia.

MATERIALS AND METHODS

CT scans of 23 consecutive patients presenting with pneumatosis or portomesenteric venous gas caused by bowel ischemia were reviewed. The presence and extent of both CT findings were compared with the clinical outcome in all patients and with the severity and extent of ischemic bowel wall damage as determined by surgery (15 patients), autopsy (three patients), or follow-up (five patients).

RESULTS

Seven patients showed isolated pneumatosis, and 16 patients showed portomesenteric venous gas with or without pneumatosis (11 and five patients, respectively). Pneumatosis and portomesenteric venous gas were associated with transmural bowel infarction in 14 (78%) of 18 patients and 13 (81%) of 16 patients, respectively. Nine patients (56%) with portomesenteric venous gas died. Of seven patients with infarction limited to one bowel segment (jejunum, ileum, or colon), only one patient (14%) died, whereas of the 10 patients with infarction of two or three bowel segments, eight patients (80%) died.

CONCLUSION

CT findings of pneumatosis intestinalis and portomesenteric venous gas due to bowel ischemia do not generally allow prediction of transmural bowel infarction, because they may be observed in patients with only partial ischemic bowel wall damage. The clinical outcome of patients with bowel ischemia with these CT findings seems to depend mainly on the severity and extent of their underlying disease.

Hepatic imaging with multidetector CT

Combining the advantages of a multirow detector array with a fast gantry rotation time, multidetector computed tomographic (CT) scanners can acquire sections at a faster rate than was previously possible. As a result, multidetector CT permits scanning during multiple specific phases of intravenous contrast enhancement and the acquisition of very thin sections over a large area, allowing the creation of multiplanar reconstructions with high z-axis resolution. The authors present an imaging strategy for the diagnosis and staging of hepatic pathologic conditions that emphasizes the role of multidetector CT. Users must master several scanning parameters to obtain the best image quality. For hepatic CT, it is practical to use relatively narrow collimation, increasing the pitch as needed to cover the entire liver. The choice of reconstruction interval is dependent on the problem for which the study is being performed. Water is recommended as an oral contrast agent for non-axial reconstructions, since high-attenuation oral contrast agents might degrade them. Appropriate scanning delays for hepatic CT are dependent on the contrast-agent injection strategy used. A triple-pass technique, highlighting the arterial, parenchymal, and portal venous phases of enhancement, is recommended.