M. Scaglione

Ischemia and infarction of the small bowel and colon: spectrum of imaging findings

Mesenteric ischemia presents as an abdominal emergency due to decreased intestinal blood flow secondary to mesenteric arterial vascular hypoperfusion, occlusion, or impaired venous drainage [1]. The small bowel or colon may be involved. Distinction between intestinal ischemia and infarction sometimes is not considered adequately in the interpretative process: the ischemia may be a transient and a totally reversible event, whereas infarction may be one of the possible consequences that requires surgical or interventional management. Despite continuing advances in imaging and surgical techniques, early detection of intestinal ischemia before infarction develops remains difficult [2]. Early diagnosis is important to improve survival rates [2, 3]; in most cases of late or missed diagnosis, mortality rate from intestinal infarction is very high, from 60% to 90% [4–6]. Prognosis of an ischemic intestinal insult depends upon clinical factors, such as its acuteness, duration and severity, the presence of collateral vascular circulation, the response of the mesenteric vascular branches and intestinal wall to the injury [7], extent of intestinal involvement, and the timeliness of diagnosis and intervention. From a phase in which the intestinal vascular injury may be suspected and the imaging findings of ischemia noted, the severity of mural damage may proceed rapidly to infarction with dire consequences. Differences in bowel wall findings may be appreciable between small bowel arterial and venous infarctions [8–10]. Radiologic descriptions of intestinal ischemia and infarction reported in the literature are rich [10–13] but not pathognomonic. Currently, there is no report of a direct correlation between bowel wall findings and a confirmed diagnosis of ischemia or infarction. Most literature on this topic is characterized by nonhomogeneous material and methodology of study. Some parameters regarding the timing of imaging in which studies are performed, intravenous and/or oral contrast medium administration, dynamics of the acute vascular injury, and the different etiologies (superior or inferior venous or arterial mesenteric vessels, occlusive or nonocclusive event) are sometimes difficult to summarize in a comparative classification. However, diagnostic imaging may play a pivotal role in the detection of the degree and severity of intestinal ischemia and assessment for evidence of infarction. In the following sections, imaging findings (wall thickness and enhancement, caliber of intestinal loops, presence of air-fluid levels, intestinal peristalsis, mesenteric arterial and venous vessel viabilities, mural and/or portal/mesenteric pneumatosis) from different method of study (abdominal plain film, sonography [US], and computed tomography [CT]) will be correlated to various phases of intestinal changes from ischemia and infarction due to mesenteric vessels hypoperfusion or occlusion based on experience in our institutions.

Role of contrast-enhanced helical CT in the evaluation of acute thoracic aortic injuries after blunt chest trauma.

The purpose of this retrospective study was to determine the value of contrast-enhanced helical CT for detecting and managing acute thoracic aortic injury (ATAI). Between June 1995 and February 2000, 1419 consecutive chest CT examinations were performed in the setting of major blunt trauma. The following CT findings were considered indicative of ATAI: intimal flap; pseudoaneurysm; contour irregularity; lumen abnormality; and extravasation of contrast material. On the basis of these direct findings no further diagnostic investigations were performed. Isolated mediastinal hematoma on CT scans was considered an indirect sign of ATAI: In these cases, thoracic aortography was performed even if CT indicated normal aorta. Seventy-seven patients had abnormal CT scans: Among the 23 patients with direct CT signs, acute thoracic aortic injuries was confirmed at thoracotomy in 21. Two false-positive cases were observed. The 54 remaining patients had isolated mediastinal hematoma without aortic injuries at CT and corresponding negative angiograms. The 1342 patients with negative CT scans were included in the 8-month follow-up program and did not show any adverse sequela based on clinical and radiographic criteria. Contrast-enhanced helical CT has a critical role in the exclusion of thoracic aortic injuries in patient with major blunt chest trauma and prevents unnecessary thoracic aortography. Direct CT signs of ATAI do not require further diagnostic investigations to confirm the diagnosis: Isolated aortic bands or contour vessel abnormalities should be first considered as possible artifacts or related to non-traumatic etiologies especially when mediastinal hematoma is absent. In cases of isolated mediastinal hematoma other possible sources of bleeding should be considered before directing patients to thoracic aortography.

The use of MRCP in the detection of pancreatic injuries after blunt trauma

From January 2000 to November 2001, five consecutive, hemodynamically stable trauma patients (age range 8–69 years, mean age 34 years) with parenchymal injurieswere evaluated by magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP). One patient also underwent a MRCP-facilitated secretin test. MRI depicted pancreatic laceration in two patients, ductal disruption and a post-traumatic intraparenchymal pseudocyst in one, migrating pancreatic fluid collection in the mediastinal space with disruption in another, and main pancreatic duct rupture and dilatation in the patient evaluated with MRCP following secretin administration. MRI with MRCP is an effective noninvasive test for detecting and managing pancreatic injuries after blunt trauma. Secretin administration improves ductal visualization, particularly of nondilated ducts. Finally, MRI was useful in the follow-up studies of parenchymal damage and minor ductal injuries, providing high-quality images of the pancreatic duct and biliary tract.

Intestinal pneumatosis in adults: diagnostic and prognostic value

Intestinal pneumatosis (IP) has been traditionally associated with intestinal infarction and poor outcome in adults; recent studies have questioned its clinical value. To assess its diagnostic and prognostic significance, we have retrospectively evaluated 102 patients correlating the CT finding of gastrointestinal parietal gas with clinical data and outcome. Fifty-three patients (52%) had surgical evidence of intestinal infarction. In the remaining patients, a variety of lesions were found including intestinal obstruction, cancer, volvulus, ulcer, hernia, trauma, Crohns disease, diverticulitis, and iatrogenic causes. We observed the presence of portal vein gas (PVG) associated to IP in 25.5% of cases. In patients having both IP and PVG, intestinal infarction was observed in 69.2% of cases. In our series, overall mortality was 30.4% (31/102), and when PVG was present, it rose to 50% (13/26). In our study, IP has been observed in a broad range of lesions with very different prognosis, the most frequent of which was intestinal infarction. When associated to PVG, there was a much higher prevalence of intestinal infarct, and the prognosis was definitively worse.

Helical computed tomography diagnosis of gastrointestinal perforation in the elderly patient

Purpose: To determine the value of helical CT in a consecutive series of elderly patients referred with clinically suspected gastrointestinal perforation. Methods: Our series comprised 34 consecutive elderly patients (mean age: 68 years) presenting with acute abdominal symptoms potentially suggestive of gastrointestinal perforation. All the patients were prospectively subjected to abdominal computed tomography (CT). On helical CT, the presence of free air was considered diagnostic of gastrointestinal perforation. Other findings such as intraperitoneal free fluid, thickening of bowel wall, streaky density within the mesentery, “dirty fat” sign, and focal collection of extraluminal fecal matter (“dirty mass”) were considered indirect findings of perforation. Results: At surgery, the following sites of perforation were found: duodenum (38.2 %), stomach (29.4 %), ileum (8.8 %), sigmoid colon (8.8 %), rectum (5.8 %), and jejunum, appendix, and transverse colon (2.9 % of cases each). CT demonstrated the presence of free air in 94.1 % of cases; intraperitoneal free fluid was present in 76.4 % of patients and thickening of bowel wall in 50 %. Streaky density within the mesentery was found in one patient. Conclusion: CT is a reliable diagnostic method by which to assess gastrointestinal perforation, because it provides excellent contrast resolution to depict the presence of even small amounts of free air in the abdomen. This is particularly helpful where elderly patients are concerned.

Radiofrequency and microwave ablation of subcapsular hepatocellular carcinoma accessed by direct puncture: Safety and efficacy

OBJECTIVESnDirect puncture of subcapsular hepatocellular carcinoma (HCC) for tumor ablation has been considered high risk due to a perceived increased incidence of hemorrhage or tumor seeding. The purpose of this retrospective multicenter study was to identify the rate of tumor seeding, hemorrhage and local tumor progression (LTP) associated with direct puncture radiofrequency (RF) and microwave (MW) ablation of subcapsular HCC.nnnMETHODSnA multicenter, retrospective review of direct-puncture RF and MW performed on subcapsular HCC was conducted. Complications and local tumor progression were documented. Data was analyzed using Kaplan-Meier and log-rank tests.nnnRESULTSnThe study group consisted of 60 cirrhotic patients (M/F=43/17; mean age 69.6 years) with 67 subcapsular HCC (mean diameter 2.3 cm ± 1.0 cm) that were directly punctured for RF (n=40) or MW (n=27) under ultrasound (US) guidance. The mean follow-up period was 30.8 months. There were no hemorrhagic complications. The overall LTP rate was 13.4%. There was one case of tumor tract seeding in a patient who had undergone a percutaneous biopsy two weeks prior to RF.nnnCONCLUSIONSnThermal ablation of HCC by direct puncture appears safe and effective. There were no cases of intraperitoneal hemorrhage, and tumor seeding was seen in a single case in which a preceding percutaneous biopsy had been performed.

Gastric pneumatosis and portal vein gas: incidental findings at helical CT after blunt abdominal trauma

Abstract Gastric pneumatosis is a rare form of intestinal pneumatosis related to a wide range of abnormalities, which by itself may not engender adverse consequences. Portal vein gas, on the other hand, has traditionally been regarded as a life-threatening condition associated with mesenteric ischemia and immediate surgery; however, recent observations have demonstrated a greater spectrum of etiologies associated with portal vein gas in which the prognosis seems to be more favorable and surgery is not necessary. We report the case of a 42-year-old man who developed gastric pneumatosis and portal vein gas after major abdominal trauma. The patient was conservatively treated. Follow-up CT performed 4 days later revealed that portal vein gas and gastric pneumatosis had resolved spontaneously.

Biopsy of Liver Target Lesions under Contrast-Enhanced Ultrasound Guidance – A Multi-Center Study

PURPOSEnu2002To retrospectively characterize the prevalence and impact of contrast-enhanced ultrasound (CEUS) as a guidance technique for the biopsy of liver target lesions (LTLs) at six interventional ultrasound centers.nnnMATERIALS AND METHODSnu2002The six participating centers retrospectively selected all patients in whom biopsy needles were positioned in LTLs during CEUS.u200aThe prevalence of CEUS-guided biopsies at each center between 2005 and 2016, contrast agent consumption, procedure indications, diagnostic yield and complications were assessed. Informed consent was obtained for all patients.nnnRESULTSnu2002CEUS-guided biopsy of LTLs was carried out in 103 patients (68u200aM/35 F, median age: 69 yrs) with 103 liver target lesions (median size: 20u200amm) using cutting needles (18u200a-u200a20u200ag) in 94 cases (91.2u200a%). CEUS-guided biopsy represented 2.6u200a% (range: 0.8u200a-u200a7.7u200a%) of 3818 biopsies on LTLs carried out at the participating centers. Indications to CEUS-guided biopsy were: a target lesion not visible on non-enhanced US (27.2u200a%), improvement of conspicuity of the target (33u200a%), choice of non-necrotic area inside the target (39.8u200a%). 26 patients (25.2u200a%) had a previously non-diagnostic cyto-histological exam. The diagnostic accuracy of the technique was 99u200a%. No major complications followed infusion of contrast agent or biopsy performance.nnnCONCLUSIONnu2002The indications for CEUS-guided biopsy for LTLs are limited, but CEUS can be useful in challenging clinical scenarios, e.u200ag. poorly visualized or invisible lesions or sampling of non-necrotic areas in the target lesions. There is also a potential advantage in using CEUS to guide repeat biopsies after unsuccessful sampling performed using the standard ultrasound technique.

Multi-detector computed tomography in the evaluation of variants and anomalies of aortic arch and its branching pattern

OBJECTIVEnEvaluate the prevalence of aortic arch anatomy and branching pattern variants and anomalies in 1359 patients by Multi-Detector Computed Tomography Angiography.nnnMETHODSnRetrospective multi-centric study including exams performed for various clinical issues with the same acquisition and injection protocols on 64-slices scanners. Multi-Planar reformations and Volume Rendering Images were available in all cases.nnnRESULTSnA total of 965 patients (71%) had normal aortic arch anatomy and branching pattern. Anatomical variations and anomalies were present in the remaining 394 patients (29%). The most common variation was the common origin of the brachiocephalic and the left common carotid arteries (302/1359 cases, about 22%). The most common anomaly were aberrant right subclavian artery (4/1359, about 0.5%) and right aortic arch (4/1359 cases, about 0.5%).nnnCONCLUSIONSnOur multicentric series is, as far as we know, the largest reported to date for the definition of the prevalence of variation and anomalies of aortic arch anatomy and branching pattern. Knowledge of such findings may avoid both in the immediate and in the long term an injury to the patient, decreasing the rate of complications during surgery and interventional radiology procedures in the head and neck district.

Gastrointestinal perforation: ultrasound diagnosis

Purpose: To investigate the spectrum of US findings as encountered in a consecutive series of patients referred with clinically suspected gastrointestinal perforation. Methods: Seventy-two consecutive patients (mean age: 42.9 years) with clinically suspected gastrointestinal perforation were prospectively examined with abdominal ultrasound (US). The US examinations were all performed by a certified senior radiologist, who was blind to other imaging findings. Patients were screened for the presence of free intraperitoneal gas (characteristic comet-tail artifacts, ring-down artifacts, and the “shifting phenomenon” were our diagnostic indicators of pneumoperitoneum). Other signs potentially suggestive of gastrointestinal perforation were also looked for, including free intraperitoneal fluid, thickening of bowel walls, gallbladder walls, gastric walls, or duodenal walls, or local peritoneal inflammation. Patients with equivocal or inconclusive findings on US were submitted to abdominal computed tomography (CT) 10–15 min after US examinations. Results: Of the 72 patients prospectively examined by US, 63 (87.5 %) underwent subsequent emergent surgery within next 2 days. A gastrointestinal perforation was found in all the 63 patients referred for operative treatment: overall, 41 gastroduodenal and 22 intestinal perforations were found. On US, in the 41 patients with surgically proven gastroduodenal perforation, the most common finding was free intraperitoneal gas (28/41, 68.3 %). The 13/41 patients (31.7 %) without evidence of free gas on US underwent preoperative abdominal CT assessment, which allowed the correct diagnosis of gastroduodenal perforation in 12/13 cases. In the 22 patients with surgically proven intestinal perforation the most common finding detected on US was free intraperitoneal fluid (14/22, 63.6 %); sonographic evidence of free intraperitoneal gas was seen in only 8/22 patients (36.4 %). The 14/22 patients (63.6 %) without free gas on US underwent preoperative abdominal CT assessment, which allowed the diagnosis of intestinal perforation in 12/14 cases. Conclusion: US examinations allow very rapid screening of patients referred with clinically suspected gastrointestinal perforation and for triage of patients who are to undergo more invasive imaging tests.