Small animal imaging facility: new perspectives for the radiologist.

In recent years, new technologies have become available for imaging small animals. The use of animal models in basic and preclinical sciences, for example, offers the possibility of testing diagnostic markers and drugs, which is becoming crucial in the success and timeliness of research and is allowing a more efficient approach in defining study objectives and providing many advantages for both clinical research and the pharmaceutical industry. The use of these instruments offers data that are more predictive of the distribution and efficacy of a compound. The mouse, in particular, has become a key animal model system for studying human disease. It offers the possibility of manipulating its genome and producing accurate models for many human disorders, thus resulting in significant progress in understanding pathologenic mechanisms. In neurobiology, the possibility of simulating neurodegenerative diseases has enabled the development and validation of new treatment strategies based on gene therapy or cell grafting. Noninvasive imaging in small living animal models has gained increasing importance in preclinical research, itself becoming an independent specialty. The aim of this article is to review the characteristics of these systems and illustrate their main applications.

Iatrogenic rectal diverticulum in patients treated with transanal stapled techniques.

PURPOSE: The aim of this study was to demonstrate the possibility of rectal diverticula developing in patients treated with endoanal circular staplers for haemorrhoids (Longo's stapled haemorrhoidectomy) or obstructed defaecation syndrome [stapled transanal rectal resection (STARR)]. MATERIALS AND METHODS: Between January 2005 and December 2006, we carried out 634 defaecographic examinations. Of these, 45 were postoperative follow-up studies of patients who had been treated with the Longo technique (n = 13) or STARR technique (n = 32). RESULTS: Seven out of 45 patients, five of whom were women treated with the Longo technique and two men with the STARR technique, developed rectal diverticula. One diverticulum was located on the left lateral rectal wall, four on the posterior wall and two on the anterior wall. All diverticula had arisen from the surgical suture point. In one case, the diverticulum was discovered incidentally during a double-contrast barium enema. One of the male patients, who had been treated with the Longo procedure 5 years earlier, developed acute pain due to faecal stasis in a widenecked diverticulum abutting the posterior rectal wall. CONCLUSIONS: The use of endorectal stapling devices can lead to focal weakness at the point of surgical suture on the rectal wall and predispose to the development of rectal diverticula.

Multidetector-row helical CT enteroclysis.

The authors illustrate the technique for small-bowel imaging using enteroclysis with multidetector-row computed tomography (MDCT), underscoring the important role played by CT in the assessment of the small bowel thanks to the advent of first the spiral and later the multidetector technique. The paper makes a detailed comparison of the various methods that have been used in CT study of the small bowel and proposes a standardised technique to achieve correct distension of bowel loops and adequate evaluation of bowel wall vascularity, making reference to the well-consolidated experiences of the various Italian research groups. The paper accurately describes the different procedures required for CT assessment of the small bowel, from nasojejunal intubation to the selection of the most appropriate acquisition phases for assessment of bowel wall vascularity.

Multiple jejunal angiodysplasia detected by enema-helical CT.

The small bowel angiodysplasia is a rare entity that causes lower intestinal bleeding; the diagnosis is difficult and based on selective angiogram. In our case, an 85-year-old woman was hospitalized after frequent episodes of melena. We performed an enema-helical CT abdominal examination before and after contrast medium administration per venam, detecting some increased intensity areas that surgery confirmed to be a vascular dysplasia on the jejunal first loop. We found the source of hemorrhage without performing an angiographic examination.

[The defecographic and clinical aspects of the solitary rectal ulcer syndrome]. / Aspetti defecografici e clinici della sindrome dell'ulcera solitaria del retto.

INTRODUCTION: Solitary rectal ulcer syndrome is a complex evacuation disorder characterized by a benign ulcerative lesion of the distal rectum; the main symptom is rectal bleeding, but mucus discharge and difficult evacuation may be associated. The clinical, endoscopic and radiologic findings of solitary rectal ulcer syndrome are evaluated in this study. The role of defecography in the diagnosis of mucosal ulceration and morphofunctional alterations such as rectal prolapse and intussusception are investigated. MATERIAL AND METHODS: In the last 5 years, 27 patients (19 women and 8 men; mean age: 38 years; range: 13-70 years) complaining of obstructed evacuation and rectal bleeding were examined with fibrosigmoidoscopy with biopsy, and defecography combined with videoproctography. Defecography was carried out sitting the patients on a defecographic chair with the pelvis in lateral projection. The images were acquired at rest, under straining, during squeezing and evacuation. RESULTS: Endoscopy and biopsy showed 21 cases of solitary ulcer (77.8%), 3 cases of multiple ulcers (11.1%), 2 cases of granular proctitis (7.4%) and 1 case of pseudopolyp of rectum (3.7%). Among anorectal dynamic alterations, only 1 case (3.7%) of large rectocele was detected at endoscopy under straining. Histo-pathological changes were compared according to Rutter and Riddel criteria; the "colitis cystica profunda" appearance was observed in 2 cases (7.4%). Defecography showed 18 cases (16.6%) of solitary ulcer, 1 case (3.7%) of multiple ulcers and 2 cases (7.4%) of granular proctitis; but it missed 3 cases (11.1%) of small solitary ulcer, 2 cases (7.4%) of small multiple ulcers, and 1 case (3.7%) of pseudopolyp. The dynamic abnormalities shown by defecography were 11 cases (40.7%) of rectal intussusception, 7 cases (25.9%) of recto-anal intussusception, 6 cases (22.2%) of external rectal prolapse and 8 cases (29.6%) of mucosal prolapse. In 16 patients (59.2%) videoprotography emphasized how the ulcer wall was the first to take part in the invagination complex. CONCLUSIONS: Double contrast barium enema represents a useful radiologic method to diagnose solitary rectal ulcer, but air insufflation and pharmacological hypotonia prevent the functional study of rectal walls. Endoscopy permits to detect mucosal ulcerations, erythema, pseudopolyps and granular proctitis; biopsy provides an accurate diagnosis. We suggest combined defecography and videoproctography as a useful tool for evaluating solitary rectal ulcer syndrome as a whole; defecography is necessary to identify associated functional abnormalities, such as rectal prolapse and intussusception, not detectable by other instrumental and radiologic investigations and considered by many authors the likely cause of the disease.

Massive enterolithiasis associated with ileal dysgenesis.

A 20-year-old man with massive ileal enterolithiasis was investigated with plain radiography, ultrasound, computed tomography, barium follow through and double contrast barium enema. Ileocecal valve agenesis was found at surgery. The enteroliths were located in the distal ileum, which communicated with the large intestine via an ileotransverse fistula.

CT and anal endosonography in the evaluation of electrically stimulated neoanal sphincter: a preliminary report.

We report a preliminary experience concerning the postoperative assessment of three patients who underwent gracilis neosphincter operation for severe fecal incontinence and were studied by computed tomography and anal endosonography soon after gracilis transposition and later after 6-8 weeks of neuromuscular training. Morphologic assessment was correlated with physiologic testing (manometry). Continence was satisfactorily improved in all patients. Both imaging techniques demonstrated the anatomy of the transposed muscle. Computed tomography also assessed lead placement onto the gracilis nerve root and the completeness of muscle transposition around the anal canal. Anal endosonography provided a more accurate assessment of the relation between the neosphincter and residual external sphincter.

[Endoanal ultrasonography, defecography, and enema of the colon in the radiologic study of incontinence]. / Ecografia endoanale, defecografia e clisma del colon nello studio radiologico dell'incontinenza.

In the last 3 years, the authors examined 564 patients with disturbed anorectal function. Of 41 incontinent subject in this series, 30 were retrospectively analyzed to assess the diagnostic contribution of double contrast barium enema, defecography and endoanal sonography. The authors propose a classification of fecal incontinence based on imaging findings: indeed, rectal incontinence can be distinguished from pelvic and sphincteral incontinence. Large bowel enema and defecography are the examinations of choice if rectal incontinence is suspected on the basis of clinical history and possible endoscopic, manometric and electromyographic findings. Defecography is suggested if pelvic incontinence is suspected, while anal endosonography is the exam of choice in case of suspected sphincteral incontinence. Especially thanks to the recent availability of the latter technique, today radiologists can directly visualize the anal sphincteral apparatus and its lesions, yielding objective evidence of this type of incontinence too. The authors report on both limitations and indications of each diagnostic method and conclude by stressing the fundamental role diagnostic imaging plays today in the study of this disorder.

[Videoproctography in the study of rectal intussusception. The authors' own experience]. / La videoproctografia nello studio dell'intussuscezione rettale. Esperienza personale.

Videoproctography has proved to be a useful diagnostic technique to investigate anorectal disorders; it can provide morphological and functional information which no other diagnostic method yields. From a series of 898 videoproctographs, the findings of 117 patients with rectal intussusception were retrospectively reviewed. The most common symptoms were an incomplete emptying feeling (93% of cases), obstructed defecation (78%), and a feeling of upright rectal weighting (71%). Of the three known types of rectal intussusception, the most common type was distal intussusception (44%), followed by the rectoanal type (38%) and finally by the proximal type (19%). The three types of intussusception were frequently (42%) associated with other disorders of rectal ampulla and especially with rectocele (15%), mucosal prolapse (8%), and descending perineum syndrome (12%); they had different clinical correlations and proctographic patterns and could be recognized in different defecation phases. In our personal experience, proctography with videorecording was a useful diagnostic tool in the dynamic assessment of this morphofunctional disorder which represents one of its major indications.

[Radiology of chronic intestinal insufficiency]. / Radiologia dell'insufficienza intestinale cronica.

Impaired intestinal function, negatively affecting food digestion and absorption, is called chronic intestinal failure (CIF). The clinical conditions leading to CIF are: fistulas, wide resections and severe damage to small bowel, and chronic intestinal stasis. In the etiology of CIF, the most frequent conditions are: Crohn's disease, postoperative peptic ulcer, mesenteric arteriopathy, radiation enteropathy, acute pancreatitis, jejunoileal diverticulosis and intestinal pseudo-obstruction. The radiologic approach to CIF can aim at: 1) diagnosing the disease and the clinical conditions causing it; 2) morphometric analysis: lesion spread, length of the extant normal small bowel and adaptive changes. Digestive tube radiology has always been considered a fundamental investigation technique to study malabsorption. Double contrast enema has increased the diagnostic capabilities of radiology. Moreover, double contrast enema allows the extraoperative evaluation, in vivo, of a new anatomic feature--i.e., intestinal length--which is a valuable sign for an exhaustive interpretation of CIF, especially of the short bowel syndrome. Thanks to double contrast enema, the changes in the length of mesenteric small bowel can be calculated in vivo (range: 150-430 cm; mean: 291 cm, SD 59). Intestinal length < 150 cm was observed only in resected patients. In 25% of cases, short small bowels were associated with CIF. Such morphometric studies, if applied to clinical practice, may yield valuable information for both diagnosis and prognosis.