Utility of the portal venous phase for diagnosing pancreatic necrosis in acute pancreatitis using the CT severity index

Acute pancreatitis and computed tomography: Interest of portal venous phase alone in the initial phase

BACKGROUND

There are no guidelines in the literature for the use of a computed tomography (CT) protocol in the initial phase of acute pancreatitis (AP).

PURPOSE

To evaluate the contribution of single portal venous phase CT compared to triple-phase CT protocol, performed in the initial phase of AP for severity assessment.

MATERIAL AND METHODS

In this retrospective study, a total of 175 patients with acute pancreatitis who underwent initial triple-phase CT protocol (non-contrast, arterial phase, and portal venous phase) between D3 and D7 after the onset of symptoms were included. Analysis of AP severity and complications was independently assessed by two readers using three validated CT severity scores (CTSI, mCTSI, EPIC). All scores were applied to the triple-phase CT protocol and compared to the single portal venous phase. Inter-observer analyses were also performed.

RESULTS

No significant difference whatever the severity score was observed after analysis of the single portal venous phase compared with the triple-phase CT protocol (interstitial edematous pancreatitis: CTSI: 2 vs. 2, mCTSI: 2 vs. 2, EPIC: 1 vs. 1; necrotizing pancreatitis: CTSI: 6 vs. 6, mCTSI: 8 vs. 8, EPIC: 5 vs. 5). Inter-observer agreement was excellent (ICC = 0.96-0.99), whatever the severity score.

CONCLUSION

A triple-phase CT protocol performed at the initial phase of AP was no better than a single portal venous for assessing the severity of complications and could lead to a 63% reduction in irradiation.

Accuracy of a CT density threshold enhancement in distinguishing pancreas parenchymal necrosis in cases of acute pancreatitis in the first week

PURPOSE

The purpose of this study was to identify attenuation threshold value on computed tomography (CT) that allowed discriminating between interstitial edematous pancreatitis (IEP) and necrotizing pancreatitis (NP) in patients with acute pancreatitis during the first week of the disease and evaluate interobserver reproducibility for the diagnosis of acute pancreatitis category.

MATERIALS AND METHODS

Patients with acute pancreatitis who underwent CT examination of the abdomen between March 2015 and December 2019 were retrospectively included. Actual diagnosis of IEP or NP was based on final clinical report, follow-up evaluation, and complications. Six regions of interest were manually placed in the pancreatic gland and peripancreatic fat, and differences in CT attenuation values before contrast injection and during the portal venous phase of enhancement were computed. Performance in the diagnosis of AP category was evaluated using receiver operating characteristic analysis. Interobserver agreement was estimated by the intraclass correlation coefficient (ICC) and Bland Altman analysis was used to estimate reproducibility between pairs of observers.

RESULTS

Sixty-six patients with NP (46 men, 20 women; mean age, 55 ± 17 [SD] years; age range: 20-89 years) and 70 patients with IEP (39 men, 31 women; mean age, 54 ± 18 [SD] years; age range: 21-87 years) were included. An enhancement value less than 30 Hounsfield units (HU) in the pancreatic gland during the portal phase compared to non-contrast phase, yielded 90.9% sensitivity (60/66; 95% CI: 81.3-96.6), 94.3% specificity (66/70; 95% CI: 86.0-98.4) and an area under curve of 0.958 (95% CI: 0.919-0.996) for the diagnosis of NP versus IEP. Interobserver reproducibility for pancreas enhancement was good using Bland Altman plot and ICC was excellent for pancreatic gland analysis (ICC 0.978; 95% CI: 0.961-0.988) but poor or moderate (ICC ≤0.634) regarding peripancreatic fat necrosis.

CONCLUSION

By using a pancreas enhancement threshold value of 30 HU, CT is accurate and reproducible for the diagnosis of NP during the first week of the disease.

Gastrointestinal bleeding due to pseudoaneurysms in children

Radiological embolization is the treatment of choice in adults with visceral artery pseudoaneurysm (PSA) and gastrointestinal bleeding, but pediatric data is scanty. We analyzed the etiology, clinical presentation, and outcome of radiological intervention in children with PSA of celiac (CA) or superior mesenteric artery (SMA) branches. Electronic records of children with PSA of CA or SMA branches were reviewed and data on clinical and laboratory profile, radiological intervention, and outcome was recorded. Eleven children with PSA (5 boys, 11 [7-17] years) were studied. Etiology was liver abscess (n 4), abdominal trauma (n 3), pancreatitis (n 3), and indeterminate in 1 case. Ten (91%) patients were symptomatic: abdominal pain (10, 91%), hematemesis/melena (9, 81%), and Quincke's triad (1, 9%). One child with pancreatic pseudocyst was diagnosed incidentally on imaging. Doppler ultrasound identified PSA only in 3 cases, while computed tomography angiography (CTA) picked all cases. Children with liver abscess, trauma, and unknown etiology had PSA from CA (right hepatic artery 7, left hepatic artery 1). Of the 3 pancreatitis cases, 2 had PSA from SMA (inferior pancreatico-duodenal artery and ileal branch) and 1 from CA (left gastric artery). Radiological embolization was done in 9 (81%) cases (coil 6, glue 2, both 1), without any complications or failure. One case resolved spontaneously and 1 died pre-intervention. Nine intervened cases were asymptomatic in follow-up [6 (1-24) months].Conclusion: Liver abscess, trauma, and pancreatitis are causes of PSA of CA and SMA branches in children. A majority present with gastrointestinal bleeding and are identified on CTA. Radiological embolization was safe with 100% success. What is Known: • Pseudoaneurysm of visceral artery is an uncommon cause of gastrointestinal bleeding. • Endoluminal intervention is an established and efficacious treatment modality in adults and preferred over surgery. What is New: • Liver abscess, abdominal trauma and pancreatitis are common causes of celiac artery and superior mesenteric artery branch pseudoaneurysm in children and computed tomography angiography has high sensitivity in identifying these pseudoaneurysms. • Minimally invasive radiological angio-embolization, in the hands of trained radiologists, is a safe and successful modality of treatment in children.