The Impact of Transient Hepatic Attenuation Differences in the Diagnosis of Pseudoaneurysm and Arteriovenous Fistula on Follow-Up CT Scans after Blunt Liver Trauma

A multi-institutional study designed by members of Tokyo Guidelines (TG) Core Meeting to elucidate the clinical characteristics and pathogenesis of acute cholangitis after bilioenteric anastomosis and biliary stent insertion with a focus on biliary obstruction: Role of transient hepatic attenuation difference (THAD) and pneumobilia in improving TG diagnostic performance

BACKGROUND/PURPOSE

The aim of this study was to clarify the clinical characteristics of acute cholangitis (AC) after bilioenteric anastomosis and stent-related AC in a multi-institutional retrospective study, and validate the TG18 diagnostic performance for various type of cholangitis.

METHODS

We retrospectively reviewed 1079 AC patients during 2020, at 16 Tokyo Guidelines 18 (TG 18) Core Meeting institutions. Of these, the post-biliary reconstruction associated AC (PBR-AC), stent-associated AC (S-AC) and common AC (C-AC) were 228, 307, and 544, respectively. The characteristics of each AC were compared, and the TG18 diagnostic performance of each was evaluated.

RESULTS

The PBR-AC group showed significantly milder biliary stasis compared to the C-AC group. Using TG18 criteria, definitive diagnosis rate in the PBR-AC group was significantly lower than that in the C-AC group (59.6% vs. 79.6%, p < .001) because of significantly lower prevalence of TG 18 imaging findings and milder bile stasis. In the S-AC group, the bile stasis was also milder, but definitive-diagnostic rate was significantly higher (95.1%) compared to the C-AC group. The incidence of transient hepatic attenuation difference (THAD) and pneumobilia were more frequent in PBR-AC than that in C-AC. The definitive-diagnostic rate of PBR-AC (59.6%-78.1%) and total cohort (79.6%-85.3%) were significantly improved when newly adding these items to TG18 diagnostic imaging findings.

CONCLUSIONS

The diagnostic rate of PBR-AC using TG18 is low, but adding THAD and pneumobilia to TG imaging criteria may improve TG diagnostic performance.

Quantification of Liver Fat Content after Radiofrequency Ablation for Liver Cancer: Correlation with Hepatic Perfusion Disorders

PURPOSE

To quantitatively investigate the correlation between liver fat content and hepatic perfusion disorders (HPD) after radiofrequency ablation (RFA) for liver cancer using magnetic resonance imaging (MRI)-determined proton density fat fraction (PDFF).

MATERIALS AND METHODS

A total of 150 liver cancer patients underwent liver MRI examination within one month after RFA and at four months after RFA. According to the liver fat content, they were divided into non-, mild, moderate, and severe fatty liver groups. The liver fat content and hepatic perfusion disorders were determined using PDFF images and dynamic contrast-enhanced MRI images. The relationship between the liver fat content and HPD was investigated.

RESULTS

At the first postoperative MRI examination, the proportion of patients in the nonfatty liver group with hyperperfused foci (11.11%) was significantly lower than that in the mild (30.00%), moderate (42.86%), and severe fatty liver (56.67%) groups (p < 0.05), whereas the proportions of patients with hypoperfused foci (6.67%, 7.5%, 5.71%, and 6.67%, respectively) were not significantly different among the four groups (p > 0.05). In the nonfatty liver group, the liver fat content was not correlated with hyperperfusion abnormalities or hypoperfusion abnormalities. By contrast, in the three fatty liver groups, the liver fat content was correlated with hyperperfusion abnormalities but was not correlated with hypoperfusion abnormalities. At the second postoperative MRI examination, six patients in the nonfatty liver group were diagnosed with fatty liver, including two patients with newly developed hyperperfusion abnormalities and one patient whose hypoperfusion abnormality remained the same as it was in the first postoperative MRI examination.

CONCLUSION

There was a high correlation between the liver fat content and hyperperfusion abnormalities after RFA for liver cancer. The higher the liver fat content was, the higher the was risk of hyperperfusion abnormalities. However, there was little correlation between liver fat content and hypoperfusion abnormalities, and the increase in postoperative liver fat content did not induce or alter the presence of hypoperfused foci.

Delayed and Chronic Sequelae of Trauma and the Role of the Interventional Radiologist

In addition to acute injury requiring interventional radiologic treatments, patients with traumatic injuries can develop delayed or chronic complications. These injuries can involve nearly all solid organs in the abdomen. Coupled with significant improvements in visualizing these injuries with advanced imaging techniques such as minimally invasive procedures, nonoperative management of both acute traumatic injuries and their longer term sequelae has become the norm. This article reviews frequently seen complications of traumatic injury and their management by interventional radiologists.

Traumatic Intraparenchymal Pseudoaneurysm on Initial Imaging Predicts Injury Progression in Patients with Nonoperative Major Blunt Liver Injury

Most patients who present with hemodynamic stability and no evidence of peritonitis after blunt liver injury are successfully managed nonoperatively. Little information is available regarding the utility of reimaging major blunt liver injuries for patients who are managed nonoperatively. A retrospective review of patients admitted to a level I trauma center with major blunt liver injuries (AAST grades 3–5) was conducted. Inclusion criteria were those admitted from July 2012 to June 2014 with blunt liver trauma who survived the first 24 hours and underwent repeat imaging. Data included demographics, procedures performed, and computerized tomography (CT) scan findings. Findings on the second CT scan were categorized as Unchanged, Worse, Improved, or Negative. A total of 128 patients had blunt major liver injuries; 66 patients underwent repeat imaging. The mean time to repeat CT was 1.95 days. On repeat CT, 47 were Unchanged, 3 Worse, 14 Improved, and 2 Negative. Three patients underwent angiography. One required embolization of a pseudoaneurysm. In 63 patients (95%), the second CT did not change the management plan. The presence of a pseudoaneurysm was significantly related to a worsening of the second CT (P = 0.0475). Patients with admission hematocrit (Hct) below 32% were more likely to have a worsened second CT (P = 0.0370). A pseudoaneurysm on admission CT and Hct &lt;32% predict major liver injury progression suggesting that routine reimaging is warranted in this group.

Differences of liver CT perfusion of blunt trauma treated with therapeutic embolization and observation management

Massive hepatic necrosis after therapeutic embolization has been reported. We employed a 320-detector CT scanner to compare liver perfusion differences between blunt liver trauma patients treated with embolization and observation. This prospective study with informed consent was approved by institution review board. From January 2013 to December 2016, we enrolled 16 major liver trauma patients (6 women, 10 men; mean age 34.9 ± 12.8 years) who fulfilled inclusion criteria. Liver CT perfusion parameters were calculated by a two-input maximum slope model. Of 16 patients, 9 received embolization and 7 received observation. Among 9 patients of embolization group, their arterial perfusion (78.1 ± 69.3 versus 163.1 ± 134.3 mL/min/100 mL, p = 0.011) and portal venous perfusion (74.4 ± 53.0 versus 160.9 ± 140.8 mL/min/100 mL, p = 0.008) were significantly lower at traumatic parenchyma than at non-traumatic parenchyma. Among 7 patients of observation group, only portal venous perfusion was significantly lower at traumatic parenchyma than non-traumatic parenchyma (132.1 ± 127.1 vs. 231.1 ± 174.4 mL/min/100 mL, p = 0.018). The perfusion index between groups did not differ. None had massive hepatic necrosis. They were not different in age, injury severity score and injury grades. Therefore, reduction of both arterial and portal venous perfusion can occur when therapeutic embolization was performed in preexisting major liver trauma, but hepatic perfusion index may not be compromised.