Elsevier

Clinical Radiology

Volume 75, Issue 10, October 2020, Pages 796.e11-796.e16
Clinical Radiology

Comparison of angio-CT versus multidetector CT in the detection and location for insulinomas

https://doi.org/10.1016/j.crad.2020.05.012Get rights and content

Highlights

  • •

    CT is the first-line imaging method for insulinoma detection and localization.

  • •

    Angio-CT is superior in the detection and location for insulinomas compared to MDCT.

  • •

    Angio-CT indicates higher tumor conspicuity compared to MDCT.

AIM

To compare the diagnostic performance of angio-computed tomography (CT) with multidetector CT (MDCT) in the detection and location for insulinomas.

MATERIALS AND METHODS

From April 2015 to April 2018, 60 consecutive patients who underwent MDCT and angio-CT for clinically suspected insulinomas were identified retrospectively. The CT attenuation values of tumours, normal pancreatic parenchyma, and tumour-to-pancreas contrast were measured quantitatively in the arterial phase (AP) and portal venous phase (PVP) of both methods by two radiologists with interobserver agreement. The detection sensitivity and localisation accuracy were calculated based on surgical and pathological findings, which are the reference standard, and compared between both methods using the chi-square test. Receiver operating characteristic (ROC) analysis was performed to compare diagnostic performance.

RESULTS

Fifty-four patients with insulinoma with a mean age of 53.8 years old (range 21–69 years) were reviewed. The detection sensitivity and location accuracy were 68.5%, 58.3% for MDCT and 94.4%, 90.7% for angio-CT, respectively; the detection sensitivity and location accuracy of angio-CT were significantly higher than those obtained with MDCT (p < 0.05). The mean tumour-to-pancreas attenuations were 105.1±25 HU in the AP of MDCT and 285±48.7 HU in the AP of angio-CT. There were significant differences in the tumour-to-pancreas contrast in the AP between MDCT and angio-CT (p < 0.05). The Az values were 0.93 and 0.84 for the AP of angio-CT and MDCT, 0.62 and 0.54 for the PVP. The AP of angio-CT was significantly more accurate for insulinoma detection (p < 0.05).

CONCLUSION

Angio-CT produces higher tumour conspicuity and is superior in the detection and location of insulinomas compared to MDCT.

Introduction

Insulinomas are the most common functioning pancreatic endocrine tumours, the classic Whipple triad is the typical clinical presentation.1 Qualitative diagnosis of hyperinsulinaemic hypoglycaemia depends upon the occurrence of severe symptomatic hypoglycaemia.2 Preoperative detection and localisation diagnosis is more important as most insulinomas are benign3 and surgical excision is the main approach.4 Multidetector (MD) computed tomography (CT) is performed routinely for preoperative detection and localisation of insulinomas as a criterion standard; however, nearly 90% of studies reported that the detection sensitivity was <70%5 due to minor attenuation differences between the lesions and the pancreatic parenchyma of some patients and 90% of insulinomas are <2 cm in diameter.3 Angio-CT may display the tumours more distinctly by increasing the attenuation differences between the lesions and pancreatic parenchyma. The aim of the present study was to compare the performance of angio-CT with MDCT in the detection and location for insulinomas in a patient group.

Section snippets

Patients

The single-centre retrospective study was approved by the institutional review board and ethics committee and informed consent was obtained from all patients. The electronic medical records and radiology data of 60 consecutive patients with clinically suspected insulinomas who underwent angio-CT and MDCT from April 2015 to April 2018 were reviewed. Patients were clinically suspected to have insulinomas according to the qualitative diagnostic criteria of hyperinsulinaemic hypoglycaemia.2 Six

Patient data

Fifty-four patients with a mean age of 53.8 years old (range 21–69 years) were reviewed from April 2015 to April 2018, the ratio of male to female patients was 1:2 (male: 18, female: 36). All patients showed symptoms of the Whipple triad, which had lasted for a mean of 36.5 months (range 3.5–126 months). The mean lowest blood glucose level, C-peptide, and insulin were 27.3 mg/dl (range 12–45 mg/dl), 4.8 ng/dl (range 1.3–24.7 ng/dl), and 29.3 mIu/ml (range 0.8–101 mIu/ml), respectively.

Discussion

CT is the first-line imaging method for insulinoma detection and localisation.9, 10, 11 Several studies have reported the detection sensitivity of CT for insulinomas ranged from 54.3% to 75.1% after 2010.12, 13, 14 The main reason that MDCT fails to detect and locate an insulinoma is isoattenuating tumours (tumour–parenchyma attenuation <15 HU)15 and vague optimised phase timing; 24.9% of 181 insulinomas were isoattenuating tumours on biphasic CT in a retrospective study.13 It is difficult for

Declaration of interests

The authors declare no conflict of interest.

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