Comparison of high-resolution contrast-enhanced 3D MRA with digital subtraction angiography in the evaluation of hepatic arterial anatomy

Angiography with cone-beam CT versus contrast-enhanced MRI for living donor transplant imaging: Is MRI enough?

The purpose of this study is to compare the subjective and objective quality and confidence between conventional angiography with cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI) for the preoperative evaluation of potential donors for living donor liver transplant. Seventeen patients undergoing preoperative donor evaluation for living donor liver transplantation that underwent angiography with CBCT and contrast-enhanced MRI for evaluation of hepatic vascular anatomy were included in the study. Four attending radiologists interpreted anonymized, randomized angiography with CBCT images and MRIs, rating the diagnostic quality and confidence of their interpretation (on a 3-point scale) for each element, as well as clinically relevant measurements. Overall, the readers rated the quality of angiography with CBCT to be higher than that of MRI (median [interquartile range] = 3 (2, 3) vs. 2 (1-3), p < 0.001) across all patients. Readers of angiography with CBCT had more confidence in their interpretations as an average of all elements evaluated than the MRI readers (3 (3) vs. 3 (2, 3), p < 0.001). When the same reader interpreted both MRI and CBCT, the right hepatic artery diameter (3.8 mm ± 0.72 mm vs. 4.5 mm ± 1.2 mm, p < 0.005) and proper hepatic artery diameter (4.43 mm ± 0.98 mm vs. 5.4 mm ± 1.05 mm, p < 0.003) were significantly different between MRI and CBCT. There was poor interrater reliability for determining segment IV arterial supply for both modalities (κ < 0.2). Angiography with CBCT provides higher subjective diagnostic quality and greater radiologist confidence than MRI. The difference in measurements between CBCT and MRI when the same reader reads both studies suggests CBCT adds additional information over MRI evaluation alone.

Clinical significance of variant hepatic artery in pancreatic resection: A comprehensive review

The anatomical structure of the pancreaticoduodenal region is complex and closely related to the surrounding vessels. A variant of the hepatic artery, which is not a rare finding during pancreatic surgery, is prone to intraoperative injury. Inadvertent injury to the hepatic artery may affect liver perfusion, resulting in necrosis, liver abscess, and even liver failure. The preoperative identification of hepatic artery variations, detailed planning of the surgical approach, careful intraoperative dissection, and proper management of the damaged artery are important for preventing hepatic hypoperfusion. Nevertheless, despite the potential risks, planned artery resection has become acceptable in carefully selected patients. Arterial reconstruction is sometimes essential to prevent postoperative ischemic complications and can be performed using various methods. The complexity of procedures such as pancreatectomy with en bloc celiac axis resection may be mitigated by the presence of an aberrant right hepatic artery or a common hepatic artery originating from the superior mesenteric artery. Here, we comprehensively reviewed the anatomical basis of hepatic artery variation, its incidence, and its effect on the surgical and oncological outcomes after pancreatic resection. In addition, we provide recommendations for the prevention and management of hepatic artery injury and liver hypoperfusion. Overall, the hepatic artery variant may not worsen surgical and oncological outcomes if it is accurately identified pre-operatively and appropriately managed intraoperatively.

Real-time respiratory motion compensated roadmaps for hepatic arterial interventions

PURPOSE

During hepatic arterial interventions, catheter or guidewire position is determined by referencing or overlaying a previously acquired static vessel roadmap. Respiratory motion leads to significant discrepancies between the true position and configuration of the hepatic arteries and the roadmap, which makes navigation and accurate catheter placement more challenging and time consuming. The purpose of this work was to develop a dynamic respiratory motion compensated device guidance system and evaluate the accuracy and real-time performance in an in vivo porcine liver model.

METHODS

The proposed device navigation system estimates a respiratory motion model for the hepatic vasculature from prenavigational X-ray image sequences acquired under free-breathing conditions with and without contrast enhancement. During device navigation, the respiratory state is tracked based on live fluoroscopic images and then used to estimate vessel deformation based on the previously determined motion model. Additionally, guidewires and catheters are segmented from the fluoroscopic images using a deep learning approach. The vessel and device information are combined and shown in a real-time display. Two different display modes are evaluated within this work: (1) a compensated roadmap display, where the vessel roadmap is shown moving with the respiratory motion; (2) an inverse compensated device display, where the device representation is compensated for respiratory motion and overlaid on a static roadmap. A porcine study including seven animals was performed to evaluate the accuracy and real-time performance of the system. In each pig, a guidewire and microcatheter with a radiopaque marker were navigated to distal branches of the hepatic arteries under fluoroscopic guidance. Motion compensated displays were generated showing real-time overlays of the vessel roadmap and intravascular devices. The accuracy of the motion model was estimated by comparing the estimated vessel motion to the motion of the X-ray visible marker.

RESULTS

The median (minimum, maximum) error across animals was 1.08 mm (0.92 mm, 1.87 mm). Across different respiratory states and vessel branch levels, the odds of the guidewire tip being shown in the correct vessel branch were significantly higher (odds ratio = 3.12, p < 0.0001) for motion compensated displays compared to a noncompensated display (median probabilities of 86 and 69%, respectively). The average processing time per frame was 17 ms.

CONCLUSIONS

The proposed respiratory motion compensated device guidance system increased the accuracy of the displayed device position relative to the hepatic vasculature. Additionally, the provided display modes combine both vessel and device information and do not require the mental integration of different displays by the physician. The processing times were well within the range of conventional clinical frame rates.

Image quality of arterial phase and parenchymal blood volume (PBV) maps derived from C-arm computed tomography in the evaluation of transarterial chemoembolization

Background

To evaluate the benefits of arterial phase imaging and parenchymal blood volume (PBV) maps acquired by C-arm computed tomography during TACE procedure in comparison to cross-sectional imaging (CSI) using CT or MRI.

Methods

From January 2014 to December 2016, a total of 29 patients with HCC stage A or B (mean age 65 years; range 47 to 81 years, 86% male) were included in this study. These patients were referred to our department for TACE treatment and received peri-interventional C-arm CT. Dual phase findings of each lesion in terms of overall image quality, conspicuity, tumor size and feeding arteries were compared between arterial phase imaging and PBV using 5-point semi-quantitative Likert-scale, whereby pre-interventional CSI served as reference standard.

Results

A significantly higher overall image quality of the PBV maps compared to arterial phase C-arm CT acquisitions (4.34 (±0.55) vs. 3.93 (±0.59), p = 0.0032) as well as a higher conspicuity of HCC lesions (4.27 ± 0.74 vs. 3.83 ± 1.08, p < 0.0001) was observed. Arterial phase imaging led to an overestimation of tumor size (mean size, 26.5 ± 15.9 mm) compared to PBV (24.9 ± 15.2 mm, p = 0.0004) as well as CSI (25.2 ± 15.1 mm), p = 0.021). Regarding detectability of tumor feeding arterial vessels, significantly more feeding vessels were detected in arterial phase C-arm CT (n = 1.67 ± 0.92 vessels) compared to PBV maps (n = 1.27 ± 0.63 vessels) (p = 0.0001). One lesion was missed in pre-interventional CT imaging, but detected by C-arm CT.

Conclusion

The combination of PBV maps and arterial phase images acquired by C-arm CT during TACE procedure enables precise detection of the majority of HCC lesions and tumor feeding arteries and has therefore the potential to improve patient outcome.

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.

Impact of 3D Rotational Angiography on Liver Embolization Procedures: Review of Technique and Applications

In the last years, the interest into interventional applications of C-arm cone-beam CT (CBCT) progressively raised, widening its clinical application from the original field of interventional neuroradiology to the field of peripheral procedures. Liver embolization procedures, due to their complexity and potential treatment-related life-threatening complications, represent one of the main clinical applications of this novel angiographic technique. CBCT has been demonstrated to render procedures safer and technically easier, and to predict outcome as well as to avoid major complications in different treatment scenarios (trans-arterial embolization, trans-arterial chemoembolization, selective internal radiation therapy, percutaneous portal vein embolization). This review summarizes all technical, dosimetric and procedural aspects of CBCT techniques, underlying all its potential clinical advantages in the field of liver embolization procedures. Moreover, the paper provides all the instructions to obtain the best diagnostic performance out of this novel angiographic technique.

Three-dimensional gadolinium-enhanced MR venography to evaluate central venous steno-occlusive disease in hemodialysis patients

AIM

To determine the agreement and diagnostic accuracy of three-dimensional gadolinium-enhanced magnetic resonance venography (3D-Gd-MRV) in central venous steno-occlusive disease (CVSD) in haemodialysis patients.

MATERIALS AND METHODS

Fourteen consecutive haemodialysis patients underwent interventional procedures to evaluate or treat CVSD. 3D-Gd-MRV was performed before the procedures and the results were compared with digital subtraction angiography (DSA).

RESULTS

DSA showed >50% stenosis in all 14 patients, 13 of whom were diagnosed correctly using 3D-Gd-MRV. Moderate stenosis was missed at 3D-Gd-MRV in one case whereby the indwelling dialysis central venous catheter may have caused an artefact on the images and hindered the accuracy of the result. The sensitivity of 3D-Gd-MRV in revealing stenosis was 93% (13/14). No complications caused by contrast agent toxicity occurred in any patient.

CONCLUSION

3D-Gd-MRV employing a non-breath-hold technique is highly sensitive in the diagnosis of CVSD and may be an alternative technique to DSA for the visualization of central veins.

Anatomical variations of hepatic arterial system, coeliac trunk and renal arteries: an analysis with multidetector CT angiography

The purpose of our investigation was to determine the anatomical variations in the coeliac trunk-hepatic arterial system and the renal arteries in patients who underwent multidetector CT (MDCT) angiography of the abdominal aorta for various reasons. A total of 100 patients were analysed retrospectively. The coeliac trunk, hepatic arterial system and renal arteries were analysed individually and anatomical variations were recorded. Statistical analysis of the relationship between hepatocoeliac variations and renal artery variations was performed using a chi(2) test. There was a coeliac trunk trifurcation in 89% and bifurcation in 8% of the cases. Coeliac trunk was absent in 1%, a hepatosplenomesenteric trunk was seen in 1% and a splenomesenteric trunk was present in 1%. Hepatic artery variation was present in 48% of patients. Coeliac trunk and/or hepatic arterial variation was present in 23 (39.7%) of the 58 patients with normal renal arteries, and in 27 (64.3%) of the 42 patients with accessory renal arteries. There was a statistically significant correlation between renal artery variations and coeliac trunk-hepatic arterial system variations (p = 0.015). MDCT angiography permits a correct and detailed evaluation of hepatic and renal vascular anatomy. The prevalence of variations in the coeliac trunk and/or hepatic arteries is increased in people with accessory renal arteries. For that reason, when undertaking angiographic examinations directed towards any single organ, the possibility of variations in the vascular structure of other organs should be kept in mind.

Comparison of dynamic MRI at 3.0 T and MDCT of pancreatobiliary disease: evaluation with source, MPR, CPR, and MIP images for image quality and hepatic arterial and portal venous vessel conspicuity

PURPOSE

To compare contrast material-enhanced three-dimensional (3D) magnetic resonance imaging (MRI) at 3.0T and multidetector row computed tomography (MDCT) in the same patient with regard to image quality of pancreatobiliary disease and hepatic vascular conspicuity.

MATERIALS AND METHODS

This study enrolled 32 patients with pancreatobiliary disease who underwent both gadolinium-enhanced 3D dynamic MRI and multiphasic CT using 16-MDCT. Data analysis of image quality was performed by two radiologists based on source images, multiplanar reconstruction (MPR), curved planar reconstruction (CPR), and maximum intensity projection (MIP) reconstruction. Determination of image quality was based on a 4-point image quality rating scale.

RESULTS

The overall image quality of the MRI axial images was superior to that of the axial MDCT images. The MRI protocol yielded an average score of 3.8 points versus 3.5 for the CT imaging. No significant difference was found between 3.0T MRI and MDCT images in MPR or CPR image quality. Image quality for visualization of the distal intrahepatic segmental arteries was significantly improved using MDCT imaging. No significant difference was found between the MDCT and 3.0T MR in portal vein branch image quality.

CONCLUSION

High-resolution dynamic contrast-enhanced MR imaging at 3.0T is a comprehensive technique which provides high image quality in pancreatobiliary disease.

Unsuspected mesenteric arterial abnormality: comparison of MDCT axial sections to interactive 3D rendering

OBJECTIVE

The purpose of our study was to determine how frequently significant mesenteric arterial abnormalities that were identified by interactive 3D CT with volume rendering and maximum intensity projection were detected by axial images alone in a series of patients for whom there was no clinical suspicion of mesenteric vascular disease. Axial CT and 3D interpretations were compared for lesions involving the celiac and superior mesenteric arteries or their branches. On a per-patient basis, the axial and 3D interpretations were equivalent in 24% (10/41) of the cases. Axial CT partially agreed with 3D CT in 10% (4/41), and no mesenteric arterial lesion was reported on axial CT in 66% (27/41). The 3D CT findings were supported by other imaging, surgery, clinical findings, or management in 49% (20/41) of the cases. The mesenteric lesions identified resulted in a change in patient management in 15% (6/41) of the subjects.

CONCLUSION

Unsuspected mesenteric arterial abnormality may elude diagnosis when axial MDCT sections are interpreted without 3D renderings.

Omental pseudocyst

Diagnostic image features of the omental cyst remain to be fully understood because of its rarity. We present here a case of omental cyst in a 29-year-old man involving several diagnostic image features. Contrasted computed tomography showed thin ring-like enhancement, and angiography revealed the feeding arteries that branched from the right gastroepiploic artery. The cyst was excised surgically, and the final pathological diagnosis was an omental pseudocyst.

Three-dimensional Rotational Angiography: Introduction of an Adjunctive Tool for Successful Transarterial Chemoembolization

Transcatheter arterial embolization (TACE) is a minimally invasive procedure that requires precise visualization of the feeding vessels to liver tumors for proper catheter placement and effective therapy. The use of three-dimensional (3D) rotational angiography (RA) can be extremely useful to the interventional radiologist during TACE while the patient is on the catheterization table. This report demonstrates the role of 3D RA in interventional oncology by presenting two cases of hepatocellular carcinoma with complex vascular anatomy successfully treated because of the information provided by this new technology.