Image Fusion Guidance with Pre-procedural CT with Real-Time Fluoroscopy for Adrenal Venous Sampling

Adrenal Vein Sampling: Tips and Tricks

Adrenal vein sampling (AVS) is the standard method for distinguishing unilateral from bilateral sources of autonomous aldosterone production in patients with primary aldosteronism. This procedure has been performed at limited specialized centers due to its technical complexity. With recent advances in imaging technology and knowledge of adrenal vein anatomy in parallel with the development of adjunctive techniques, AVS has become easier to perform, even at nonspecialized centers. Although rare, anatomic variants of the adrenal veins can cause sampling failure or misinterpretation of the sampling results. The inferior accessory hepatic vein and the inferior emissary vein are useful anatomic landmarks for right adrenal vein cannulation, which is the most difficult and crucial step in AVS. Meticulous assessment of adrenal vein anatomy on multidetector CT images and the use of a catheter suitable for the anatomy are crucial for adrenal vein cannulation. Adjunctive techniques such as intraprocedural cortisol assay, cone-beam CT, and coaxial guidewire-catheter techniques are useful tools to confirm right adrenal vein cannulation or to troubleshoot difficult blood sampling. Interventional radiologists should be involved in interpreting the sampling results because technical factors may affect the results. In rare instances, bilateral adrenal suppression, in which aldosterone-to-cortisol ratios of both adrenal glands are lower than that of the inferior vena cava, can be encountered. Repeat sampling may be necessary in this situation. Collaboration with endocrinology and laboratory medicine services is of great importance to optimize the quality of the samples and for smooth and successful operation. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Benefits of adrenal venous sampling with preoperative four-dimensional CT imaging

BACKGROUND

The effects of adrenal venous sampling (AVS) may be limited by the anatomical variants of adrenal veins.

PURPOSE

To investigate the benefits of AVS for patients who underwent four-dimensional computed tomography (4D CT) before AVS.

MATERIAL AND METHODS

We reviewed the images of contrast-enhanced four phase three-dimensional (3D) and 4D CT in patients who received AVS between February 2010 and February 2021. A total of 112 patients (59 women; mean age = 55.3  ± 11.8 years) were enrolled. Of the entire population, 49.1% (55/112) underwent 4D CT, whereas 50.9% (57/112) underwent 3D CT. The anatomical features of adrenal veins and procedural data were obtained. Simple linear regression analyses were performed to determine the relationship between imaging protocols and AVS.

RESULTS

On comparison of the two groups, the 4D cohort had a higher success rate (98.2% vs. 78.9%; P = 0.001), shorter procedure and fluoroscopy time (73.6 ± 37.3 min vs. 110.5 ± 47.9 min; P < 0.001 and 28.7 ± 31.2 min vs. 97.4 ± 251.7 min; P = 0.047, respectively), lower radiation exposure (243.5 ± 315.5 mGycm² vs. 613.4 ± 674.6 mGycm²; P < 0.001) and less contrast volume (46.2 ± 42.7 ml vs. 68.3 ± 47.4 ml vs; P = 0.014). In simple linear regression analysis, positive and negative identification of right adrenal vein before AVS significantly influenced the success rate (unstandardized coefficients [UC] = 0.304, standardized coefficients [SC] = 0.304; P = 0.001) and operation duration (UC = -46.124, SC = -0.318; P = 0.001).

CONCLUSION

Pre-procedural 4D CT may facilitate successful AVS. Compared with four-phase 3D CT, this protocol is better to shorten the operation and fluoroscopy time, and to reduce the radiation dose and contrast consumption.

Pre-interventional assessment of right renal to right adrenal vein distance: Impact on procedure time and radiation dose in adrenal vein sampling

PURPOSE

Adrenal vein sampling (AVS) is the reference standard for evaluation of lateralized hormone production in primary aldosteronism. We aimed to investigate the impact of pre-interventional right renal vein (RRV) to right adrenal vein (RAV) distance measurement on fluoroscopy time, contrast agent exposure and radiation dose during AVS.

MATERIALS AND METHODS

Forty-five patients with primary aldosteronism undergoing AVS were enrolled in our retrospective study and divided into three groups. In the group "ruler" (n = 14), RRV-RAV-distances were determined pre-interventionally by cross-sectional imaging (CT/MRI) and AVS was performed by one interventional radiologist with limited experience in AVS. CT/MRI-derived and fluoroscopy-derived RRV-RAV-distances were correlated for aimed cannulation of the RAV. Patients in group "no ruler" (n = 24, three interventional radiologists with limited experience in AVS) and in group "expert", (n = 7, one expert interventional radiologist) underwent AVS without pre-interventional estimation of RRV-RAV-distances. Procedure parameters (fluoroscopy time, contrast agent volume, radiation dose) of group "ruler" were compared to both other groups by Kruskal-Wallis rank-sum test.

RESULTS

Correlation of CT/MRI-derived and fluoroscopy-derived RRV-RAV-distances was good (r = 0.74;p = 0.003). The median RRV-RAV-distance was 4.5cm at CT/MRI (95%-CI:4.2-5.0cm) and 4.0cm at fluoroscopy (95%-CI:3.8-4.5cm). Fluoroscopy time (p<0.0001), contrast agent exposure (p = 0.0003) and radiation dose (air kerma and dose area product both p = 0.038) were significantly lower in group "ruler" compared to group "no ruler" (all p<0.05), and similar to group "expert" (all p>0.05).

CONCLUSIONS

CT/MRI-derived pre-interventional renal-adrenal vein distance measurements correlate well with angiographic distance measurements. Pre-interventional estimation of the RRV-RAV-distance allows for aimed cannulation of the RAV with potential reduction of fluoroscopy time, contrast agent exposure and radiation-dose during AVS.

Does Intraprocedural CT Improve the Success Rate of Adrenal Venous Sampling? A Systematic Review and Meta-Analysis of Data from 809 Patients

PURPOSE

To perform a systematic review and meta-analysis to quantify the technical success rate of adrenal venous sampling (AVS) with and without intraprocedural computed tomography (CT).

METHODS

A systematic search of the Medline, Scopus, EMBASE, and Web of Science databases for comparative studies using intraprocedural CT was undertaken. More than 1,000 records were screened using titles and abstracts. Full texts of 121 studies were reviewed and 14 eligible studies were identified. Nine studies had adequate comparative data and were included in the meta-analysis.

RESULTS

A research synthesis was performed and data from 809 patients were pooled in multiple random effect models. Overall success rate of AVS without and with intraprocedural CT was 72.7% (59.3-83.0%) and 92.5% (86.6-95.9), respectively. The addition of intraprocedural CT increased the technical success rate by 19.8% (P < 0.001), with an odds ratio (OR) of 5.5 (3.3-9.2; P < 0.01). In meta-regression, odds of success with intraprocedural CT was associated with younger age (beta: 0.16 ± 0.05; P:0.001), higher body mass index (BMI; beta:0.08 ± 0.03; P:0.002), and higher selectivity index (defined as the ratio of cortisol in the adrenal vein to that in the inferior vena cava; beta:0.35 ± 0.08, P < 0.001). We found a linear inverse association between operator's success without CT and improved success with intraprocedural CT (R²: 0.86).

CONCLUSIONS

Intraprocedural CT is not required for every case, but can be performed in difficult cases or when operators' success is limited. The benefit was more pronounced in younger patients with higher BMI, female gender, and with higher selectivity.

LEVEL OF EVIDENCE

III Systematic review and meta-analysis of non-randomized clinical trials.

High Deep Femoral Artery Bifurcation Can Disturb Safe Femoral Venous Access: CT Assessment in Patients Who Underwent Femoral Venous Access Under Doppler Ultrasound Guidance

PURPOSE

To retrospectively evaluate the variations of deep femoral artery (DFA) bifurcation on computed tomography (CT) and technical success in femoral venous access.

MATERIALS AND METHODS

CT images of 353 patients who underwent adrenal venous sampling were evaluated. Height with relation to the inferior border of the femoral head and direction of DFA bifurcations were classified as follows: type L, low bifurcation; type H1, high lateral bifurcation; type H2, high posterior to posterolateral bifurcation; type H3, high posteromedial bifurcation; and type H4, high medial bifurcation crossing in front of the femoral vein. Technical success and complications during femoral venous access were also evaluated.

RESULTS

The frequencies of types L, H1, H2, H3, and H4 were 82.7%, 9.1%, 6.9%, 0.4%, and 0.9%, respectively. In 92.2% of type H1 and 69.4% of type H2, the superior femoral artery displaced medially by the high DFA partially overlapped the femoral vein. Upon the inclusions of H3 and H4, in 14.4% of cases, the high DFAs could obstruct the access route to the femoral vein. Using Doppler ultrasound guidance, no significant differences were observed in the rates of success for puncture in the first attempt (84.5% vs. 75.4%, p = 0.122) and accidental arterial puncture (1.0% vs. 0%, p = 1.00) between low and high DFA bifurcations, respectively.

CONCLUSIONS

High DFA bifurcation is observed in 17.3% of patients and could obstruct the access route to the femoral vein. This can be evaluated using Doppler ultrasound guidance to avoid accidental arterial puncture during femoral venous access.

Computed tomography image fusion, Coaxial guidewire technique, Fast intraprocedural cortisol testing technique improves success rate and decreases radiation exposure, procedure time, and contrast use for adrenal vein sampling

BACKGROUND

Adrenal vein sampling (AVS) is recommended for discriminating patients with unilateral primary aldosteronism from bilateral disease. However, it is a technically demanding procedure that is markedly underused. We developed a computed tomography image fusion, coaxial guidewire technique, fast intraprocedural cortisol testing (CCF) technique to improve AVS success rate, which combines CT image fusion, coaxial guidewire technique, and fast intraprocedural cortisol testing.

OBJECTIVE

To evaluate the effectiveness and safety of the AVS--CCF technique.

METHODS

We retrospectively evaluated 105 patients who undervent AVS from June 2016 to October 2020. There were 51 patients in the AVS--CCF group and 54 patients in the AVS group. We compared two groups with technical success rate, procedure time, radiation exposure, volume of contrast medium, and complications (adrenal vein rupture, dissection, infarction, or thrombosis; intraglandular or periadrenal hematoma; and contrast-induced nephropathy).

RESULTS

The technical success rate was higher for AVS--CCF than for AVS without CCF (98 vs. 83.3% for bilateral adrenal veins, P = 0.016). AVS--CCF was associated with a shorter procedure time (63.6 ± 24.6 vs. 94.8 ± 40.8 min, P < 0.001), shorter fluoroscopy time (15.6 ± 12.6 vs. 20.4 ± 15.0 min, P = 0.043), and lower contrast medium volume (25.10 ± 21.82 vs. 44.1 ± 31.0 ml, P < 0.001). There were no significant differences between groups with respect to the time for cannulating the left or right adrenal vein or the peak skin radiation dose. Adrenal vein rupture occurred in 14 patients and intraglandular hematoma in 1 patient.

CONCLUSION

The CCF technique during AVS not only contributed to improved technical success rates but also associated with decreased procedure time, radiation exposure, and contrast medium volume.

Safety and feasibility of unilateral double femoral venous access including double sheath insertion via a single-hole method for adrenal venous sampling

PURPOSE

To assess the safety and feasibility of unilateral double femoral venous access including double sheath insertion via a single-hole method (two-in-one method) for adrenal venous sampling (AVS).

MATERIALS AND METHODS

Two 5-Fr sheaths were percutaneously inserted into a single femoral vein for AVS in 324 patients. Two needles were inserted sequentially in tandem under ultrasound guidance; furthermore, two sheaths were individually inserted (two-in-two method) if both punctures were successfully achieved. In the presence of a single puncture, two sheaths were inserted through two guidewires and a temporarily inserted sheath (two-in-one method). This protocol was repeated until two sheaths were successfully inserted. Thus, two sheaths were inserted with the two-in-one method in 56 patients (17.3%) and two-in-two method in 268 patients (82.7%).

RESULTS

No significant differences in the technical success rates of AVS were observed (p = 0.067-0.647). Minor groin hematoma was observed more frequently in the two-in-one than in the two-in-two method (8.9% vs. 2.6%, p = 0.039). No major groin hematoma, deep venous thrombosis, or pulmonary embolization was observed. The mean number of needle puncture was 2.5 ± 1.3 and duration of inserting two sheaths 5.1 ± 3.9 min.

CONCLUSION

Unilateral double femoral venous access including the two-in-one method is safe and feasible for AVS.

Disease monitoring of Primary Aldosteronism

Primary aldosteronism (PA) is a highly prevalent cause of arterial hypertension featuring excess cardiovascular events. A timely diagnosis and treatment of PA cures hyperaldosteronism and can provide resolution or improvement of arterial hypertension, even when the latter is resistant to drug treatment. Accordingly, strategies to screen early and widely the hypertensive patients for PA by means of simplified diagnostic algorithms are justified. Such strategies are particularly beneficial in subgroups of hypertensive patients, who are at the highest cardiovascular risk. Broadening of screening strategies means facing with an increased number of patients where monitoring the disease becomes necessary. Hence, after identification of the surgically and non surgically curable cases of PA and implementation of targeted treatment physicians are faced with the challenges of follow-up, which are scantly discussed in the literature. Hence, the purpose of this paper is to provide some recommendations on how to optimize the monitoring of patients in whom the PA subtype has been diagnosed and treatment, either with unilateral laparoscopic adrenalectomy or medically, has been instituted.