Multiple gastrinomas

Victoria Rebollo Hurtado, MD1; Dulce Adoración Sánchez Nava, MD1; Pâmela Bertolazzi, BS2
1 Computed Tomography Department, CT Scanner de México, México City, México 
2 Siemens Healthineers, LAM

2024-01-26
A 37-year-old female patient, complaining of chronic epigastric pain, had had a cholecystectomy as treatment but the pain persisted. She was referred to CT to investigate a suspected Zollinger Ellison Syndrome. A previous endoscopy had revealed hypertrophic gastric folds and a 10 mm gastric polyp, whose histopathological analysis showed a well differentiated neuroendocrine tumor (Ki-67 1%). A high blood level of serum gastrin (4,699 pg/ml) was also found. As multiple endocrine neoplasia (MEN) syndrome was clinically suspected, a multiphase dynamic CT scanning of the upper abdomen was performed over the whole arterial phase, with thin slice reconstruction to capture all potential lesions. This was followed by a Dual Energy (DE) CT scan of the entire trunk in venous phase to rule out parathyroid gland lesions and other potential metastases. As part of the standard protocol, the patient was prepared with oral water administration prior to the CT scan.

Endocrine hypervascular tumors enhance and wash-out early and can easily be missed with standard arterial phase timing. Dynamic scanning with selective phase averaging solves this problem. Averaged CT image data of the early arterial phase were created from the 12-phase dynamic data using syngo.via CT Dynamic Angio. Here a total of 7 lesions were depicted, ranging from 5.3 to 31.4 mm in maximum 3D diameter. 4 lesions were in the pancreas and 3 in the duodenum, of which 2 were located outside of the Passaro’s triangle. A synchronous “time to peak” at around 30 s*, approximately 3 seconds earlier than that of the normal pancreas, was observed in their enhancement curves, compatible with multiple gastrinomas. Cinematic volume rendering technique (cVRT) was applied for 3D visualization, and this showed the pancreaticoduodenal arteries feeding the largest lesion located in the pancreatic head, as well as both the distal splenic artery and the gastroepiploic artery closely adjacent to the lesion located in the pancreatic tail. DECT images acquired in the venous phase showed two nodules in the bilateral parathyroids, characterizing adenomas, in consistence with multiple endocrine neoplasia type I (MEN I). There were no signs of metastases. Subsequently, a cerebral MRI was also performed which ruled out a hypophysis tumor. 

The patient was referred to an oncological center. A PET/CT examination was performed and showed octreotide uptake of the lesions. Medical treatment with Lanreotide was initiated with serum gastrin level monitoring and PET/CT follow up. As her serum calcium was at a normal level, the two lesions in bilateral parathyroids remained under surveillance.

Axial images show the locations of the 7 lesions – 4 in the pancreas, 3 in the duodenum, of which 2 are outside of the Passaro’s triangle. A cVRT image shows a three-dimensional overview (7 lesions in green) and a clip from the cholecystectomy.
Courtesy of Computed Tomography Department, CT Scanner de México, México City, México

Fig. 1: Axial images (Fig. 1a–1e, 1 mm) show the locations of the 7 lesions (arrows) – 4 in the pancreas, 3 in the duodenum, of which 2 are outside of the Passaro’s triangle. A cVRT image (Fig. 1f) shows a three-dimensional overview (7 lesions in green) and a clip from the cholecystectomy (arrow).

cVRT images show the pancreaticoduodenal arteries feeding the largest lesion in the pancreatic head, as well as both the distal splenic artery and the gastroepiploic artery closely adjacent to the smaller lesion in the pancreatic tail.
Courtesy of Computed Tomography Department, CT Scanner de México, México City, México

Fig. 2: cVRT images show the pancreaticoduodenal arteries feeding the largest lesion in the pancreatic head (Fig. 2a–2c, arrows), as well as both the distal splenic artery and the gastroepiploic artery closely adjacent to the smaller lesion (Fig. 2d, arrow) in the pancreatic tail.

The time attenuation curve of the 4 selected larger lesions shows synchronous “time to peak” at around 30 s, approximately 3 seconds earlier than that of the normal pancreas, compatible with multiple gastrinomas. Note that the 2 hyperdense lesions in the pancreas are already isodense with the pancreas 10 s later.
Courtesy of Computed Tomography Department, CT Scanner de México, México City, México

Fig. 3: The time attenuation curve (Fig. 3a) of the 4 selected larger lesions shows synchronous “time to peak” at around 30 s, approximately 3 seconds earlier than that of the normal pancreas, compatible with multiple gastrinomas. Note that the 2 hyperdense lesions in the pancreas (Fig. 3b, arrows) are already isodense with the pancreas 10 s later (Fig. 3c, arrows).

DECT images acquired in the venous phase show two nodules in the bilateral parathyroids, characterizing adenomas.
Courtesy of Computed Tomography Department, CT Scanner de México, México City, México

Fig. 4: DECT images acquired in the venous phase show two nodules (arrows) in the bilateral parathyroids, characterizing adenomas.

Zollinger Ellison Syndrome is caused by gastrinomas, neuroendocrine tumors characterized by the secretion of gastrin with resultant excessive gastric acid production, causing severe peptic ulcer disease and diarrhea. Gastrinomas are mostly sporadic, usually malignant and frequently multiple. They are more commonly located in the duodenum (usually <1 cm) than in the pancreas (average 3–4 cm). Some of them are seen in the setting of MEN I, an autosomal dominant genetic disease that results in proliferative lesions in multiple endocrine organs, particularly the pituitary gland, pancreas and parathyroid glands, also known as Wermer syndrome. Gastrinomas are difficult to locate due to their small size and multicentricity. In a CT examination,they are often hypervascular, with a peak contrast enhancement shown in the early arterial phase. In case this optimal time window is missed during image acquisition, the lesions, especially the smaller ones, may appear isodense with the enhancing pancreatic parenchyma and may be missed. To address this challenge, a dedicated multiphase dynamic CT scanning is performed in this case – 12 phases are acquired every 3 s, with a start delay of 11 s after contrast agent injection. Images are then reconstructed in 1 mm thin slices, aiming at the small lesions. All 7 lesions, including the smallest one – only 5.3 mm in size, are successfully depicted. The cVRT images demonstrated the feeding arteries and the relationship between the lesion and the adjacent arteries in three dimensions, facilitating future surgical planning with an appropriate approach. 

Scanner

SOMATOM Force

Scan area

Upper Abdomen

Trunk

Scan mode

Dynamic Angio

DECT

Scan length

175 mm

595 mm

Scan direction

Shuttle

Cranio-caudal

Scan time

12 x 1.5 s scans every 3 s

13 s

Tube voltage

80 kV

80/Sn150 kV

Effective mAs

150 mAs

67/38 mAs

Dose modulation

N/A

CARE Dose4D

CTDIvol

33.8 mGy

2.6 mGy

DLP

674.7 mGy*cm

160.9 mGy*cm

Rotation time

0.33 s

0.5 s

Pitch

1.0

0.6

Slice collimation

192 x 0.6 mm

192 x 0.6 mm

Slice width

1.0 mm

1.5 mm

Reconstruction increment

1.0 mm

1.0 mm

Reconstruction kernel

Br36

Qr40 3

Contrast

370 mg/mL

NA

Volume

50 mL + 30 mL saline

NA

Flow rate

4.2 mL/s

NA

Start delay

11 s

70 s