Selective intra-arterial calcium stimulation with hepatic venous sampling for preoperative localization of insulinomas

Single center experience in localization of insulinoma by selective intraarterial calcium stimulation angiography - a case series of 15 years

Background

Insulinomas are rare insulin-secreting neuroendocrine neoplasms of the pancreas. First-line treatment is the surgical removal of the tumor, however, the localization with standard imaging techniques is often challenging. With the help of selective intraarterial calcium stimulation the insulinoma's localization can be narrowed down to one third of the pancreas which the selected artery supplies.

Objective

We aimed to prove the usefulness of the calcium stimulation test in case of 9 patients treated between 2006 and 2021 diagnosed with endogenous hyperinsulinemic hypoglycemia confirmed by fasting test, where conventional imaging methods, like transabdominal ultrasound, CT or MRI failed to detect the source of hyperinsulinemia.

Methods

We performed selective intraarterial calcium stimulation with angiography with calcium gluconate injected to the main supporting arteries of the pancreas (splenic, superior mesenteric and gastroduodenal arteries); blood samples were obtained from the right hepatic vein before, and 30, 60 and 120 seconds after calcium administration.

Results

With selective angiography we found a significant elevation of insulin levels taken from the right hepatic vein in five of the nine cases. On histopathology, the lesions were between 1-2 cm, in one case malignancy was also confirmed. In four patients we found a significant rise of insulin levels obtained from all catheterized sites, which confirmed the diagnosis of nesidioblastosis. In three cases no surgery was performed, and the symptoms relieved with medical treatment.

Conclusions

Selective intraarterial calcium stimulation remains an important tool in localization of the source of insulin excess, especially in cases where other diagnostic modalities fail.

Usefulness of selective arterial calcium injection tests for functional pancreatic neuroendocrine tumors

The selective arterial calcium injection (SACI) test is useful for patients with functional pancreatic neuroendocrine tumors (F-PNETs). This study evaluated which patients with F-PNETs would benefit from the SACI test. We retrospectively analyzed the preoperative findings of patients on computed tomography (CT), magnetic resonance imaging (MRI), CT angiography (CTA), and the SACI test. Fourteen patients who underwent pancreatectomy between January 1997 and September 2016 for F-PNETs were evaluated. We classified these patients into groups A, B, and C; group A, one tumor detected by either CT or MRI; group B, multiple tumors detected; and group C, the tumor location was accordant on CT, MRI, and CTA, but the SACI test revealed another tumor. In group A, the tumor was also detected by CTA and the SACI test was positive on calcium injection. In group B, the focus tumor among the multiple tumors was detected by the SACI test. In group C, another tumor was identified by the SACI test, whose location was different from that detected using CT and MRI. The SACI test is more useful for multiple F-PNETs on CT or MRI. If CT or MRI detects a single tumor, the SACI test or CTA may be unnecessary.

Diagnostic value of ASVS for insulinoma localization: A systematic review and meta-analysis

BACKGROUND

Previous studies on the diagnostic value of arterial calcium stimulation with hepatic venous sampling (ASVS) for the localization of insulinoma have reported inconsistent results. Here, we performed a meta-analysis of the relevant published studies.

METHODS

PubMed, Embase, Web of Science, the Cochrane Library, and Wanfang Data were searched for studies on the diagnostic value of ASVS in insulinoma localization published up to May 2019. We calculated the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and receiver operating characteristic (ROC) curve of ASVS in the localization of insulinoma.

RESULTS

We included ten studies involving 337 patients in the study. The pooled sensitivity, specificity, PLR, and NLR were 0.93 (95% confidence interval [CI]: 0.83-0.97), 0.86 (95%CI: 0.75-0.93), 6.8(95%CI: 3.7-12.7), and 0.08 (95%CI: 0.03-0.19), respectively. The DOR was 84 (95%CI: 30-233), and the area under the ROC curve was 0.96 (95%CI: 0.94-0.97).The results of the heterogeneity of the studies (P = 0.00, I2 = 80.17) were calculated using forest plots of the DOR.

CONCLUSION

ASVS is of significant value in localization of insulinoma. If a qualitative diagnosis of insulinoma is definite and the imaging examination results are negative, ASVS should be performed to confirm the localization of insulinoma.

Hyperinsulinaemic hypoglycaemia in children and adults

Pancreatic β cells are functionally programmed to release insulin in response to changes in plasma glucose concentration. Insulin secretion is precisely regulated so that, under normal physiological conditions, fasting plasma glucose concentrations are kept within a narrow range of 3·5-5·5 mmol/L. In hyperinsulinaemic hypoglycaemia, insulin secretion becomes dysregulated (ie, uncoupled from glucose metabolism) so that insulin secretion persists in the presence of low plasma glucose concentrations. Hyperinsulinaemic hypoglycaemia is the most common cause of severe and persistent hypoglycaemia in neonates and children. At a molecular level, mutations in nine different genes can lead to the dysregulation of insulin secretion and cause this disorder. In adults, hyperinsulinaemic hypoglycaemia accounts for 0·5-5·0% of cases of hypoglycaemia and can be due either to β-cell tumours (insulinomas) or β-cell hyperplasia. Rapid diagnosis and prompt management of hyperinsulinaemic hypoglycaemia is essential to avoid hypoglycaemic brain injury, especially in the vulnerable neonatal and childhood periods. Advances in the field of hyperinsulinaemic hypoglycaemia include use of rapid molecular genetic testing for the disease, application of novel imaging techniques (6-[fluoride-18]fluoro-levodopa [¹⁸F-DOPA] PET-CT and glucagon-like peptide 1 (GLP-1) receptor imaging), and development of novel medical treatments (eg, long-acting octreotide formulations, mTOR inhibitors, and GLP-1 receptor antagonists) and surgical therapies (eg, laparoscopic surgery).

Surgical approach and perioperative complications determine short-term outcomes in patients with insulinoma: results of a bi-institutional study

BACKGROUND

Despite advancements in radiologic imaging and minimally invasive surgery, the evaluation and management of insulinomas is institution and surgeon dependent. Therefore, the reported surgical outcomes are highly variable. We compared the surgical management and outcomes of insulinomas between two international tertiary-care surgical units to better identify the best management as determined by short-term outcomes.

METHODS

We performed a retrospective review of patients who underwent surgery for insulinomas over a 117-month period at UT Southwestern Medical Center in Dallas (UTSW) and Queen Mary Hospital in Hong Kong (QMHK). Data collected included imaging studies, operative procedure, complications, and outcomes.

RESULTS

Thirty-seven patients were identified. Preoperative localization by computed tomography (CT) scan was successful in 21 patients (63.9%). In Hong Kong, 16 patients underwent selective arterial cannulation and calcium stimulation (SACST) with a success rate of 87.5%. Surgical management consisted of enucleation in 24 patients and distal pancreatectomy in 13 patients. Thirty patients underwent a concurrent intraoperative ultrasound, with localization in 96.7%. Laparoscopic procedures were accomplished in 20 patients. Nine postoperative complications were identified, four occurring in the laparoscopic group. Patients undergoing laparoscopic procedures had a decreased length-of-stay (LOS) compared with patients undergoing an open procedure and patients who had uncomplicated surgery had a trend toward decreased LOS.

CONCLUSION

Though the accuracy of CT scans for localizing insulinomas is only 64%, the addition of SACST or intraoperative ultrasound and pancreatic palpation increases accuracy to 97.1%. Compared with open procedures, laparoscopic resection is associated with comparable complication rates and shorter hospital length of stay.

Intraoperative ultrasound with palpation is still superior to intra-arterial calcium stimulation test in localising insulinoma

AIM

This study assessed the sensitivities of preoperative localisation modalities such as computed tomography (CT), magnetic resonance imaging (MRI), arteriography and arterial stimulation venous sampling (ASVS) using serum insulin and C-peptide gradients to intraoperative techniques in localising insulin-secreting tumours in our institution.

METHODS

Fourteen patients with proven insulinoma, aged 20-66 years, who presented from 1997 to 2004, were studied retrospectively. All patients underwent ASVS where C-peptide and/or insulin gradients were calculated. The results were compared with the preoperative findings of CT, MRI, arteriography, as well as intraoperative ultrasound and palpation.

RESULTS

Intraoperative ultrasound with palpation correctly localised 10 of the 11 tumours with a sensitivity of 91%. Sensitivities of other localisation techniques were lower: 31% by CT, 50% by MRI, and 46% by arteriography. ASVS with insulin gradients alone allowed accurate localisation in 40% of patients while localisation using only C-peptide gradients of more than 2 was 43%. The insulinomas, measuring 10-30 mm, were successfully removed in 13 patients--6 from the body, 4 from the tail, 2 from the head and 1 from the junction of the body and tail. All except 1 were cured by selective surgery and remained free of hypoglycaemia over the next 2-60 months of follow-up. One patient had left lobectomy due to liver metastases from a malignant insulinoma and remained asymptomatic with medical therapy.

CONCLUSIONS

Intraoperative ultrasound with palpation is a highly sensitive method for the localisation of insulinoma compared with other preoperative localisation techniques.

A novel technique in selective venous sampling in the localization of parathyroid tumours utilizing a micro-wire and standardized catheter

Selective venous sampling (SVS) is a useful technique to localize a number of hormone-producing tumours, such as parathyroid tumours, when other imaging techniques are inconclusive. Typically, a 5 French selective single end-hole catheter and standard hydrophilic wire are utilized to access the required vessels and an attempt made to withdraw blood. However, most interventional radiologists are familiar with the difficulty and limited success in withdrawing venous blood through an end-hole catheter. We describe a simple, cheap and novel technique utilizing a micro-wire that we have developed in our interventional suite to overcome this common problem. Having reached the target site with the selective end-hole catheter, a Tuohy Borst adapter is attached to the catheter end. A 0.018-inch micro-wire is then inserted through the selective end-hole catheter such that the distal wire tip exits the distal catheter tip. The purpose of the micro-wire exiting the catheter is to both straighten the catheter tip to a position parallel to the vessel, allowing easier aspiration as well as physically preventing blockage of the catheter by the vein intimal wall collapse on suction. The 5-ml sample required for PTH assay is then successfully obtained via the Tuohy Borst adapter.

Angiography and arterial stimulation venous sampling in the localization of pancreatic neuroendocrine tumours

Insulin- and gastrin-secreting neuroendocrine tumours of the pancreas are often very small at presentation because of the potent effects of their hormonal outputs, and they may therefore prove difficult to localize preoperatively. This is despite the advances made in recent years in cross-sectional imaging techniques, especially multidetector-row computed tomography and endoscopic ultrasound. In this chapter the techniques of angiography and arterial stimulation venous sampling used for the localization of these neoplasms are described; a combination of these two modalities provides both anatomical and functional data that are not available with other localization techniques, thereby improving operative outcome.