Anterior cruciate ligament reconstruction: MR imaging findings.

More than two million people tear their anterior cruciate ligament (ACL) each year, and ACL reconstruction occupies a significant proportion of everyday orthopedic practice, being one of the most commonly performed sports medicine surgical procedures. Patients with postoperative symptoms are frequently imaged to monitor ligament grafts and to identify complications. Given the number of patients undergoing ACL reconstruction, knowledge of the potential complications of this surgery is essential for radiologists. This article provides a review of imaging of ACL reconstruction procedures and the potential complications specific to this surgery.

RECTAL IMPACTION DUE TO PRICKLY PEAR SEEDS BEZOAR: A CASE REPORT.

Fecal impaction is the third cause of lower gastrointestinal tract obstruction after strictures for colon cancer and postoperative adhesions. A rapid diagnosis is necessary to avoid complications due to intestinal obstruction. Rectal phytobezoar due to prickly pear fruit seeds are an extremely rare entity, in the literature about twenty similar cases are described. Prickly pears are common in many countries, even in the Mediterranean area. When the ingestion of their fruit is excessive, this can be harmful, leading to the formation of phytobezoar causing fecal impaction. We describe the first case of phytobezoar due to prickly pear fruit seeds in continental Europe: a 76-year-old Italian female who ingested almost 40 prickly pear fruit leading to the composition of a large rectal phytobezoar. The patient presented clinically with fecal impaction, diagnosed by imaging and successfully treated by rectal irrigation and manual disimpaction. Our aim is to remind the physicians of these risks in evaluating patients with intestinal obstruction, when there is positive anamnesis for provenience from some areas in which these fruits are eaten. We also want to underline the role of Imaging Multi Detector Computed Tomography (MDCT) in the diagnosis of these very uncommon entities.

7T mMR in the assessment of acute arterial mesenteric ischemia in a rat model.

To validate a rat model of acute arterial mesenteric ischemia correlating MRI patterns with macro and microscopic changes in the small bowel. Thirty Sprague-Dawley rats were assigned to two experimental groups (Group I and Group II) of fifteen rats each. Group I underwent surgical procedure of superior mesenteric artery (SMA) ligation, followed by macroscopic observation. In Group II, a loop was tied loosely around the SMA without occluding the vessel. Three days after surgery, the loop was tied by external tips to completely occlude the artery. 7T microMR (7Tesla microMR) was performed before and 8 hours after SMA occlusion. At predetermined time-points the histopathological examinations were performed in both of groups. Macroscopic monitoring revealed thinning of mesenteric vessels, hypotonic reflex ileus and chromatic change of some loops. 7T microMR sequences evidenced loop dilation with gas-fluid mixed stasis, intraperitoneal free fluid and bowel wall hyperintensity. There were no significant differences in the histological analysis between the two groups. The gap of three days from surgery, adopted in the Group 2, allowed to avoid signs of peritoneal and mesenteric irritation which could bias imaging patterns. MR succeeded to identify the signs of arterial mesenteric ischemia.

Intestinal Ischemia: US-CT findings correlations.

BACKGROUND: Intestinal ischemia is an abdominal emergency that accounts for approximately 2% of gastrointestinal illnesses. It represents a complex of diseases caused by impaired blood perfusion to the small and/or large bowel including acute arterial mesenteric ischemia (AAMI), acute venous mesenteric ischemia (AVMI), non occlusive mesenteric ischemia (NOMI), ischemia/reperfusion injury (I/R), ischemic colitis (IC). In this study different study methods (US, CT) will be correlated in the detection of mesenteric ischemia imaging findings due to various etiologies. METHODS: Basing on experience of our institutions, over 200 cases of mesenteric ischemia/infarction investigated with both US and CT were evaluated considering, in particular, the following findings: presence/absence of arterial/venous obstruction, bowel wall thickness and enhancement, presence/absence of spastic reflex ileus, hypotonic reflex ileus or paralitic ileus, mural and/or portal/mesenteric pneumatosis, abdominal free fluid, parenchymal ischemia/infarction (liver, kidney, spleen). RESULTS: To make an early diagnosis useful to ensure a correct therapeutic approach, it is very important to differentiate between occlusive (arterial,venous) and nonocclusive causes (NOMI). The typical findings of each forms of mesenteric ischemia are explained in the text. CONCLUSION: At present, the reference diagnostic modality for intestinal ischaemia is contrast-enhanced CT. However, there are some disadvantages associated with these techniques, such as radiation exposure, potential nephrotoxicity and the risk of an allergic reaction to the contrast agents. Thus, not all patients with suspected bowel ischaemia can be subjected to these examinations. Despite its limitations, US could constitutes a good imaging method as first examination in acute settings of suspected mesenteric ischemia.

Seven-Tesla micro-MRI in early detection of acute arterial ischaemia: evolution of findings in an in vivo rat model.

PURPOSE: Acute mesenteric ischaemia (AMI) is a life-threatening vascular emergency with a high mortality rate. Early diagnosis is the key to reducing its mortality rate and improving the quality of life. Although computed tomography (CT) is still the gold standard for acute intestinal disorders, over the last few years, magnetic resonance imaging (MRI) has become a useful alternative tool. An animal model of AMI was developed in order to study the effectiveness of MRI in early detection of this condition and to observe lesion evolution. METHODS: Thirty Sprague Dawley rats were randomly divided into two groups (n=15): in the first group, after laparotomy, the animals underwent ligation of the superior mesenteric artery (SMA), followed by macroscopic monitoring and histological evaluation; in the second, ischaemia was induced by squeezing a loop around the SMA 3 days before evaluation with 7-T micro-MRI. RESULTS: Macroscopically, a reflex spastic ileus followed by reflex hypotonic ileus and colour changes in some of the loops were detected. MRI evidenced luminal dilatation with air-fluid levels, free intraperitoneal fluid and bowelwall oedema. Histological analysis confirmed ischaemia and earlier damage involving the central portion of the ileum. CONCLUSIONS: This model shows the correct sequence of events during arterial AMI and demonstrates that MRI can be recommended for early diagnosis of these lesions.