Cumulative Radiation Exposures from CT Screening and Surveillance Strategies for von Hippel-Lindau–associated Solid Pancreatic Tumors

Abstract

on Hippel-Lindau (VHL) syndrome is a familial neoplasia syndrome that occurs in approximately one of 36 000 live births (1). The clinical manifestations of VHL include central nervous system hemangioblastomas, retinal hemangiomas, endolymphatic sac tumors, pheochromocytomas, pancreatic tumors and cysts, including pancreatic neuroendocrine tumors (PNETs), and renal cysts and renal cell carcinomas (1). The condition is caused by a germline pathogenic variation in the VHL tumor suppressor gene and is inherited in an autosomal dominant fashion (2).Most of the recommended screening guidelines for pancreas tumors involve nonionizing radiation-emitting imaging modalities (sonography and MRI) instead of CT. If repeated during a lifetime, CT can be associated with substantial radiation exposure (Table 1) (3-8). Both CT (9) and MRI (10) have high sensitivity for the depiction of PNETs, and one report (11) suggested superior sensitivity for intravenous contrast agent-enhanced CT over MRI for the depiction of small PNETs. Hence, some organizations recommend the use of CT in asymptomatic adults (3,12). The frequency of imaging examinations varies in the different guidelines, with some recommending annual screening (1,(4)(5)(6)(7)12,13) and others, biennial evaluations (3,14) depending on whether a pancreatic and/or kidney tumor was already detected in the patient. The medical surveillance of VHL-related PNETs is adapted according to clinical characteristics of the patient and imaging features. MRI is most often used for surveillance of VHL-associated renal cell carcinoma. However, CT is certainly acceptable and may be recommended when needed (3,5,7).The surveillance protocols for patients with VHL are mainly based on several analyses performed in the National Institutes of Health prospective studies and primarily involve repeated CT scans.

Phakomatoses and Endocrine Gland Tumors: Noteworthy and (Not so) Rare Associations

“…In VHL patients, current surveillance guidelines regarding pNETs and more largely pancreatic lesions suggest first abdominal imaging between 8 and 15 years of age ( Figure 4 ) ( 86 , 87 ). MRI is recommended over CT scan to limit the consequences of repeated ionizing radiation exposure ( 159 ). Due to the non-functional characteristic of most pNETs, there is no indication for systematic biological follow-up.…”

New Prospects on Neuroimaging in Von Hippel Lindau Disease—A Narrative Review

“…Considering the fact that PET/CT imaging results in lower patient radiation exposure (5-7 mSv depending on the type of study) compared to conventional CT (8-24 mSv depending on the area and use of contrast), this could potentially be a sensible choice for screening and monitoring tumors associated with VHL [27]. Performing CT screening on individuals with von Hippel-Lindau syndrome can lead to significant radiation exposure, even when using dual-energy virtual non-contrast CT, potentially increasing the risk of secondary malignancies in patients with Von Hippel-Lindau syndrome [28]. It is also worth mentioning again that the recommended contrast-enhanced MRI in VHL patients is associated with the risk of gadolinium accumulation in the central nervous system, the consequences of which remain unknown.…”

Effects of Contrast Phases on Automated Measurements of Muscle Quantity and Quality Using CT

“…First, it is the most widely used, and it is embedded in most CT examinations for abdominal evaluation [31][32][33]. Unlike PVP, UP is not always included in the examination, particularly for individuals requiring repetitive CT scans to reduce radiation exposure hazards [34], and other contrastenhanced phases (e.g., AP, DP) are less frequently used [31][32][33]. Second, the timing of PVP is usually not subject to the hemodynamics of individuals [18,35], and it generally uses fixed timing after contrast administration [18,35].…”