When Air is a Red Herring: Benign Appearances of Air in Unusual Locations

Objective To investigate radiological features on computed tomography (CT) in the diagnosis of portal venous and intestinal wall gas in patients with ischemic bowel disease. Methods The clinic-pathological data of 17 patients with portal venous and intestinal gas associated with ischemic bowel diseases from Wenzhou People's Hospital (n=6), Yueqing People's Hospital (n=5), Shanghai Xuhui Dahua Hospital (n=3) and the Second Affiliated Hospital of Wenzhou Medical University (n=3) from January 2013 to October 2016 were analysed retrospectively. All the patients have been fasting for 8 h prior to CT scans. Enhanced CT study was performed following routine CT with no abdominal pressure for breathless scanting. Portal venous gas, intestinal wall gas, intestinal thickness and density, mesentery thickness, celiac effusion, and severity of intestinal wall enhancement were recorded. Results All the 17 patients experienced abdominal distension and pain. Additionally, nausea and vomiting was observed in 9 patients, diarrhea in 7, melena in 7, periumbilical tenderness in 11 and rebound tenderness in 8. CT scans of these 17 patients showed portal venous gas, including massive prune-tree signs of hepatic vein and portal vein (n=11) and scanty gas shadows in distal hepatic vein (n=6). Intestinal gas sign was determined in all these patients (n=17), including single shadow (n=8), multiple shadow (n=7), and band-shaped bubble (n=2). Furthermore, CT study indicated extensive intestinal wall thickening with edema (n=13), predominate luminal extension of thinner bowels (n=4), scanty celiac effusion (n=3). Enhanced CT scans demonstrated 8 patients with decreased enhancement of intestinal wall and mesentery with diseases, target and halo signs observed in enhanced scans. Conclusions Portal venous and intestinal wall gas may demonstrate distinctive CT imaging. CT study could have superior sensitivity and specialty in clinical diagnoses of ischemic bowel diseases. Key words: Portal venous gas; Intestinal wall gas; Ischemic bowel disease; Tomography, X-ray computer

Transarterial radioembolization (TARE) is a relatively new treatment optionavailable for unresectable hepatocellular carcinoma (HCC). TARE therapy involves the delivery of radiation directly to the tumor to cause tumor necrosis. Yttrium-90 (Y90) is commonly used as a source of radioembolization in TARE. TARE is very well tolerated and has a low rate of complications. Main complications of TARE for HCC include postembolization syndrome and radiation-induced injury to nearby organs such as the liver, gallbladder, and stomach, causing hepatitis, cholecystitis, or gastric ulceration. A side effect not previously described in TARE literature is portal venous gas after TARE therapy. We present the first ever reported case of portal and variceal venous gas in a 77-year-old male patient who had unresectable HCC and had previously failed chemotherapy. He underwent Y90 TARE for HCC. Following TARE, he presented with right upper quadrant abdominal pain, and imaging showed portal and variceal venous gas. He was treated with antibiotics, with resolution of symptoms and improvement in portal and variceal venous gas on repeat imaging.

When Air is a Red Herring: Benign Appearances of Air in Unusual Locations

Hepatic portal venous gas [HPVG] is not a common finding in daily practice. It is usually associated with mesenteric ischemia and bowel necrosis in adults. Combination of intratumoral gas in metastatic liver lesions with HPVG is quite rare and thought to be associated with chemotherapy-induced necrosis and infection of the necrotized metastasis Objective: Here we present a case of gastric adenocarcinoma with portal venous and intratumoral gas in metastatic liver lesions due to the infected necrosis. The patient was presented to the emergency room with severe abdominal pain and septic condition after the second round of chemotherapy. Hepatic portal venous and intratumoral gas in metastatic liver lesions due to the infected necrosis of liver metastasis was detected in computed tomography images. There were no findings of mesenteric ischemia both clinically and radiologically. Massive intratumoral infected necrosis in metastatic liver lesions and fistulization to the right portal vein branches were detected on abdominopelvic CT. Secondary infection of the necrotic metastases and fistulization to portal vein branches was believed to cause the air in metastatic liver masses and portal venous gas. Infected necrosis of metastatic liver lesions and fistulizations to the portal venous structures is extremely rare. Clinicians and radiologists should be aware of such a rare complication because early detection is crucial for patient management..

Portal venous gas and surgical outcome of neonatal necrotizing enterocolitis

A 62-year old man who presented unwell with no specific symptoms or signs was found to have portal venous circulation gas complicating a small diverticular abscess. He was successfully managed with a course of antibiotics and had full resolution of symptoms, therefore avoiding the need for surgical intervention. While most commonly associated with bowel ischaemia and therefore often warranting emergency laparotomy, portal venous gas within the context of other underlying pathology often presents opportunities for delayed surgery or more conservative management options.

The presence of portal and systemic venous gas is traditionally regarded as an ominous radiological sign indicating a grave prognosis. With advances in imaging technology, the incidence of its detection has increased along with its association with clinically benign disorders. We present a young patient with systemic and portal venous gas after traumatic lumbar puncture.

Management Algorithm for Pneumatosis Intestinalis and Portal Venous Gas: Treatment and Outcome of 88 Consecutive Cases

INTRODUCTION: Portal venous gas is a rare radiological finding that demonstrates the accumulation of gas in the portal vein and its branches. It is associated with multiple pathological conditions some of which have grave prognosis and need immediate intervention. We report a case in which extensive gas was found within the hepatic portal venous and mesenteric vessels in a patient with gastric distention secondary to a bezoar. CASE DESCRIPTION/METHODS: The patient was a 53 year old male with a history of schizophrenia, maintained on psychiatric medications, who presented with complaints of vomiting and abdominal pain after binging hot dogs. Patient was found to be hypotensive, tachycardia and anemic. There was no blood noted on the rectal exam but NGT lavage produced large amounts of coffee grounds. CT abdomen displayed a distended stomach, extensive portal venous air, foci of air in multiple mesenteric vessels with dilated small bowel loops (C). Patient underwent a diagnostic laparoscopy which showed viable bowel without ischemia or incarceration. Subsequent EGD performed for hematemesis showed an ulcerating mass lesion starting in the cardia and extending into the gastric fundus (A). Biopsy revealed squamous epithelium with food particles and without malignant cells. Of note, the patient had an EGD two months prior and no mass was noted. Patient symptoms improved with NGT decompression and metoclopramide. Repeat CT showed complete resolution of previous findings (D) while repeat EGD revealed no mass lesion. With gastric distention and motility improvement all of the patients concerning findings had resolved. DISCUSSION: It has been postulated that disruption in mucosal integrity, intraluminal pressure and intestinal microflora contribute to the pathogenesis of hepatic venous gas. It is most commonly associated with bowel necrosis and very few case reports exist of a bezoar causing such findings. Bezoars can cause gastrointestinal complications like bleeding, gastric outlet obstruction or perforation. Our patient was on psychiatric medications which is known to cause slowing of gastric motility thus leading to the development of the gastric bezoar and gastric dilation. We believe that this resulted in an increase in intra-luminal pressure thus leading to the development of hepatic portal venous and mesenteric gas. This case illustrates not only how a bezoar can lead to bleeding and diffuse portal venous air but how history and prior records can help avoid unnecessary work up.Figure 1.: Ulcerating mass lesion starting in the cardia and extending into the gastric fundus.Figure 2.: Extensive portal venous air, foci of air in multiple mesenteric vessels with dilated small bowel loops.Figure 3.: Complete resolution of air in the portal and mesenteric vessels after disappearance of mass in the cardia.

To retrospectively describe and categorize the presence of portal venous gas (PVG) from radiofrequency (RF) ablation of hepatic tumors. The study was HIPAA compliant, and informed consent was waived. Thirty-four consecutive computed tomography (CT)-guided percutaneous RF ablations of liver tumors in 26 patients (13 men, 13 women; mean age, 69 years) with five hepatocellular carcinomas and 21 metastatic liver tumors (13 colon, five other, and three unknown primary tumors) were performed with an institutional review board-approved protocol. Two treatment modalities were used: RF ablation alone (13 procedures) and combined RF ablation and ethanol injection (21 procedures). Presence of PVG was quantified with three parameters: maximum length of a portal venous branch with gas, number of Couinaud segments in which PVG was seen, and total number of portal venous branch points with gas. Then an overall PVG score from 0 to 5 was determined. Also, when tumoral gas was seen on CT scans, the largest cross-sectional area of gas was measured. The two ablation methods were compared for quantities of PVG and tumoral gas. The role of N(2)O anesthetic in PVG and tumoral gas formation during ablation also was studied. Statistical analyses were performed with Wilcoxon rank sum and Student t tests. In 25 procedures (74%), gas was found in portal vein branches; in 30 procedures (88%), gas was also found in tumoral and peritumoral tissues. There was no significant difference in frequency of PVG between the ablation methods. Combined therapy yielded significantly greater lengths of PVG (P < .002) and more portal venous branch points (P < .001) than did RF ablation alone. Mean PVG score was 2.4 +/- 0.4 (standard error of the mean) for combined therapy and 0.9 +/- 0.2 for RF ablation alone (P < .004). N(2)O anesthetic was associated with greater amounts of tumoral gas (P < .008) and PVG (P < .03). Tumoral gas, peritumoral gas, and PVG dissipated within 20 minutes after ablation in all patients. No morbidity or mortality was associated with PVG. RF ablation is a common yet benign cause of transient PVG, tumoral gas, and peritumoral gas. Combined RF and ethanol ablation was associated with more PVG than was RF ablation alone.

Portal venous gas has traditionally been considered an indicator of a poor prognosis due to bowel necrosis. Portal venous gas has recently been detected in patients with various clinical conditions, such as Crohn's disease, chemotherapy, and blunt abdominal injury without bowel necrosis. We herein report the first case of a patient with rectal cancer in whom portal venous gas developed after low anterior resection without anastomotic leakage or bowel necrosis. A 66-year-old man who had undergone low anterior resection started having severe diarrhea the day after the operation. A fever was present for 2 days after the operation but resolved on postoperative day 3. The patient complained of abdominal pain 5 days postoperatively. Computed tomography showed portal venous gas. Emergency open laparotomy was performed, but only limited ascites fluid without leakage or bowel necrosis was found. We irrigated the abdominal cavity and performed an ileostomy with insertion of a drainage tube in the rectovesical pouch. Only serous ascites was discharged through the drainage tube. The portal venous gas disappeared 3 days after the second operation. The patient was discharged in good condition 21 days after the first operation. Portal venous gas can develop after rectal surgery without anastomotic leakage or bowel necrosis. Conservative treatment is reasonable for patients without signs of bowel necrosis or panperitonitis. However, patients with portal venous gas must be carefully observed because portal venous gas may be life threatening.

Portal Venous Gas on Point-of-Care Ultrasound in a Case of Cecal Ischemia.

BackgroundPortal venous gas has traditionally been considered an inevitable harbinger of death due to its association with bowel necrosis. Recently, an increasing number of cases of portal venous gas have been reported in patients with various clinical conditions and without bowel necrosis. We herein report the case of a patient in whom portal venous gas developed after transverse colon cancer surgery.Case presentationA 69-year-old man who had transverse colon cancer underwent insertion of a transanal ileus tube for decompression. Transverse colon resection was performed on the 11th day after the insertion of the transanal ileus tube. The patient had a high fever on the 6th day after the operation. Computed tomography showed portal venous gas over the entire area of the liver and pneumatosis intestinalis in the wall of the ascending colon. There were no signs of anastomotic leakage or bowel necrosis, so we decided to use conservative therapy with fasting and antibiotics. The portal venous gas disappeared on the 19th day after the operation. The patient was discharged in good condition on the 29th day after the operation.ConclusionsConservative treatment for portal venous gas is reasonable for patients without signs of anastomotic leakage or bowel necrosis. However, it is important to carefully observe patients with portal venous gas during conservative treatment because portal venous gas may be life-threatening.

BackgroundWhether portal venous gas (PVG) is a sign of severe neonatal necrotizing enterocolitis (NEC) and predicts poor prognosis remains uncertain.MethodsPatients from two centres were randomly assigned to a training set or a validation set. A nomogram model for predicting severe NEC was developed on the basis of the independent risk factors selected by least absolute shrinkage and selection operator (LASSO) regression analysis and multivariate logistic regression analysis. The model was evaluated based on the area under the curve (AUC), calibration curve, and decision curve analysis (DCA).ResultsA total of 585 patients met the study criteria, and propensity score matching resulted in 141 matched pairs for further analysis. Patients with PVG had a greater risk of surgical intervention or death compared with patients without PVG. A prediction model for severe NEC was established based on PVG, invasive mechanical ventilation (IMV), serum platelet count (PLT) and pH <7.35 at the onset of NEC. The model had a moderate predictive value with an AUC > 0.8. The calibration curve and DCA suggested that the nomogram model had good performance for clinical application.ConclusionA prediction nomogram model based on PVG and other risk factors can help physicians identify severe NEC early and develop reasonable treatment plans.ImpactPVG is an important and common imaging manifestation of NEC.Controversy exists regarding whether PVG is an indication for surgical intervention and predicts poor prognosis.Our study suggested that patients with PVG had a greater risk of surgical intervention or death compared with patients without PVG.PVG, IMV, PLT and pH <7.35 at the onset of NEC are independent risk factors for severe NEC.A prediction nomogram model based on PVG and other risk factors may help physicians identify severe NEC early and develop reasonable treatment plans.

814 Management Algorithm for Pneumatosis Intestinalis and Portal Venous Gas