CT angiography of the visceral vasculature

A rare variation of celiac trunk and hepatic artery complicating pancreaticoduodenectomy: A case report and literature review

RATIONALE

Anatomical variations of the celiac trunk and the hepatic artery are of considerable importance in hepatopancreatobiliary surgery, liver transplants, and radiological abdominal interventions.

PATIENT CONCERNS

Here, we report a 57-year-old man with 2 weeks of painless progressive jaundice. Preoperative imaging and cytology brush results suggested an ampullary tumor and common hepatic artery anomaly (CTA) was reported. The patient underwent pancreaticoduodenectomy (PD). Intraoperatively, the CHA and gastroduodenal artery (GDA) were abnormal. The CHA emerged from the superior mesenteric artery (SMA). Computer tomography angiography (CTA) was performed postoperatively; surprisingly, the left gastric artery (LGA) and splenic artery (SA) arising from the anterior wall of the abdominal aorta replaced the normal structure of the celiac trunk, and an accessory left hepatic artery (LHA) emerged from the LGA.

DIAGNOSES

The patient was diagnosed with cholangiocarcinoma and accompanying extremely rare variation of celiac trunk and hepatic artery.

INTERVENTIONS AND OUTCOMES

The patient underwent PD and had an uneventful postoperative evolution. There was no recurrence of the tumor and with normal liver function during the 10-month follow-up.

INTERVENTIONS

The patient underwent PD and had an uneventful postoperative evolution.

OUTCOMES

There was no recurrence of the tumor and with normal liver function during the 10-month follow-up.

LESSONS

Surgeons must keep in mind that arterial variation may be present in the vascular structures intraoperatively, even if it was not revealed in preoperative imaging. The preoperative identification of arterial variation and its relationship with the tumor is necessary to avoid intraoperative vascular injury and complications after surgery.

Isolated visceral small artery fibromuscular hyperplasia-induced ischemic colitis mimicking inflammatory bowel disease

A unique case of fibromuscular hyperplasia (FMH) of the visceral vasculature is presented. A 31-yr-old patient presented with a chronic colitis initially diagnosed as ulcerative colitis 1 yr earlier. On presentation, the endoscopic appearance showed deep linear ulcerations and cobblestoning and was more consistent with Crohn's disease. Biopsies of the area, however, suggested an ischemic etiology. The patient failed to respond to local 5ASA and prednisone therapy and progression of the disease led to a left hemicolectomy. A diagnosis of a small vessel fibromuscular arteriopathy was made on the resected specimen. This is the first case presentation of FMH mimicking inflammatory bowel disease. The lack of any systemic involvement of FMH with isolated small vessel disease has never been reported and serves as an index case of which clinicians should be aware. The literature is reviewed and the possible implications are discussed.

Biphasic CT with mesenteric CT angiography in the evaluation of acute mesenteric ischemia: initial experience

PURPOSE

To evaluate the sensitivity and specificity of biphasic computed tomography (CT) with mesenteric CT angiography in the diagnosis of acute mesenteric ischemia (AMI).

MATERIALS AND METHODS

Sixty-two patients with clinically suspected AMI underwent prospective imaging with biphasic multi-detector row CT. Mesenteric CT angiography was performed with 1.25-mm collimation starting 25 seconds after 140 mL of intravenous contrast agent was administered at a rate of 4 mL/sec, followed by portal venous phase imaging with 5-mm collimation and a 60-70-second delay. CT angiograms were reconstructed with multiplanar (including transverse), maximum intensity projection, and volume-rendered techniques. All scans were evaluated prospectively by two independent radiologists for CT evidence of ischemia. AMI was confirmed with surgical or pathologic proof in 25 of 26 patients. In one patient, AMI was confirmed with clinical findings and serial CT examinations. In patients with AMI, sensitivity and specificity of each CT sign were calculated retrospectively by using patients who did not have intestinal ischemia as a control group. CT criteria that optimized sensitivity and specificity for the diagnosis of AMI were then developed.

RESULTS

AMI was diagnosed in 26 patients. The CT angiogram depicted arterial disease in eight patients and altered care in five. A finding of any one of pneumatosis intestinalis, venous gas, superior mesenteric artery occlusion, celiac and inferior mesenteric artery occlusion with distal SMA disease, or arterial embolism was 100% specific but only 73% sensitive. Alternatively, a finding of bowel wall thickening in addition to focal lack of bowel wall enhancement, solid organ infarction, or venous thrombosis was 50% sensitive and 94% specific. By using either of these criteria for the diagnosis, a sensitivity of 96% and a specificity of 94% can be achieved.

CONCLUSION

Biphasic CT with mesenteric CT angiography is effective in the diagnosis of AMI.

Helical computed tomographic portography in ten normal dogs and ten dogs with a portosystemic shunt

Contrast enhanced helical computed tomography (CT) of the liver and portal system is routinely performed in human patients. The purpose of this project is to develop a practical protocol for helical CT portography in the dog. Ten clinically normal dogs were initially evaluated to develop a protocol. Using this protocol, ten dogs with confirmed portosystemic shunts (PSS) were then evaluated. Each patient was anesthetized, and a test dose of sodium iothalamate (400 mg I/ml) at 0.55 ml/kg was injected. Serial images were acquired at the level of T12-13 or T13-L1. The time to maximum enhancement of the portal vein was determined. This time period was used as the period between the second injection (2.2 ml/kg) and the start of the helical examination of the cranial abdomen. Delay times for normal dogs ranged from 34.5 s-66.0 s (median: 43.5 s) or 1.41 s/kg-4.12 s/kg (median: 2.09 s/kg). For patients with a PSS, the delay times were 16.5-70.5 s (median: 34.5 s) or 1.47-19.17 s/kg (median: 3.39 s/kg). The aorta, caudal vena cava, portal vein, shunt vessels, and their respective branches were well visualized on the CT images. Clinical case results were surgically confirmed. The surgeons reported that the information gained from the CT portography resulted in a subjective decrease in surgical time and degree of dissection necessary compared with similar surgeries performed without angiographic information. We believe that helical CT portography in the dog will be a useful adjunct in the diagnosis of PSS. The use of helical CT portography may allow clinicians to give clients a more accurate prognosis prior to surgery and will allow patients with lesions that are not surgically correctable to avoid a costly and invasive procedure.

Variant hepatic arterial anatomy revisited: digital subtraction angiography performed in 600 patients

PURPOSE

To evaluate and describe the prevalence of hepatic arterial variants seen at digital subtraction angiography in a large series of patients.

MATERIALS AND METHODS

Data were collected prospectively by using an arterial anatomy database questionnaire that was completed at the time each visceral angiographic examination was performed from May 1996 to October 2000.

RESULTS

Six hundred patients underwent at least one visceral angiographic examination at one institution during the study period. Three hundred sixty-eight (61.3%) patients had the standard hepatic arterial anatomy. One hundred nineteen (19.8%) patients had variant left hepatic arteries (LHAs), and 89 (14.8%) had variant right hepatic arteries (RHAs). Twenty-eight (4.7%) patients had a variant anatomy involving both the LHA and the RHA. Twenty-four (4.0%) patients had a variant origin of the common hepatic artery (CHA) arising from either the superior mesenteric artery (SMA) or the aorta. In two patients, the proper hepatic artery (PHA) was the first branch of the SMA and the gastroduodenal artery (GDA) was a branch of the celiac axis. Double hepatic arteries were seen in 22 (3.7%) patients. Trifurcation or quadrifurcation of the GDA was seen in 50 (8.3%) patients, and the GDA originated distal to one hepatic artery in 25 (4.2%) patients in whom both hepatic arteries originated from the CHA.

CONCLUSION

A replaced LHA was less common than has been previously reported, and in two cases, the PHA arose from the SMA. Digital subtraction visceral angiographic results are comparable to results of seminal angiographic studies in which the cut-film technique was used.

Dynamic contrast-enhanced three-dimensional MR imaging of liver parenchyma: source images and angiographic reconstructions to define hepatic arterial anatomy

PURPOSE

To assess the accuracy of an interpolated breath-hold T1-weighted three-dimensional (3D) gradient-echo (GRE) magnetic resonance (MR) imaging sequence with near-isotropic pixel size (</=2.3 mm) for evaluation of hepatic arterial anatomy variants during dynamic liver parenchymal imaging and to report patterns of hepatic arterial anatomy.

MATERIALS AND METHODS

Liver MR imaging, including an interpolated breath-hold 3D GRE sequence with fat suppression (4.2/1.8 [repetition time msec/echo time msec], 12 degrees flip angle), was performed in 207 consecutive patients before and after gadopentetate dimeglumine administration. Of the 207 patients, 202 (98%) had technically satisfactory studies clearly defining the hepatic arterial system. The first contrast material-enhanced GRE acquisition was timed for optimal arterial enhancement with a timing examination. In a retrospective review, hepatic arteries were evaluated on the basis of arterial phase images interpreted by two independent readers using transverse source images complemented by multiplanar reconstructions. Twenty-three patients also underwent digital subtraction angiography, which was a reference standard for comparison.

RESULTS

Conventional hepatic arterial anatomy was demonstrated in 135 (67%) of 202 patients. In the 23 patients with angiographic correlation, no discrepancy was noted between MR imaging and digital subtraction angiographic findings.

CONCLUSION

Hepatic arterial anatomy can be reliably demonstrated during liver parenchymal imaging with an optimally timed contrast-enhanced isotropic 3D GRE sequence.