Pancreatic neuroendocrine neoplasms at magnetic resonance imaging: comparison between grade 3 and grade 1/2 tumors

Figures & data

Figure 1 Flow diagram of the study patients with PanNETs.

Abbreviations: Mn, magnetic resonance imaging; PanNET, pancreatic neuroendocrine neoplasms; PanNENs, pancreatic neuroendocrine neoplasms.

Table 1 Clinical data of patients

Variables	Total	PanNETs G1/G2 (n=47)	PanNEC G3 (n=12)	P-value
Age (years)	54.2±10.8 (25–76)	53.4±10.4 (28–76)	56.4±11.6 (25–71)	>0.05
Sex				0.04
Male	30	19	11
Female	29	28	1
Clinical symptoms
Abdominal pain	18	8	10	<0.001
Confusion of consciousness or dizziness	9	8	1	>0.05
Hypodynamia	5	3	2	>0.05
Others	8	7	1	>0.05
Asymptomatic	21	19	2	>0.05
Location				>0.05
Pancreatic head-neck	34	28	6
Pancreatic body-tail	25	19	6
WHO classification
G1	34	34
G2	13	13
G3	15		12

Abbreviations: WHO, World Health Organization; PanNEC G3, pancreatic neuroendocrine carcinoma G3; PanNETs, pancreatic neuroendocrine tumors.

Figure 2 A 65-year-old female with a pathologically proven, grade 1 neuroendocrine tumor in the pancreatic head.

Notes: On T1 - (A) and T2 (B)-weighted imaging, the tumor showed hypointensity and hyperintensity, respectively. On diffusion-weighted imaging (b =1,000 s/mm²) (C), the lesions showed slight hyperintense signal with a well-defined border. Gadolinium-enhanced images in the arterial phase (D) and portal phase (E), the tumor (arrow) is shown. ADC maps (F) showed an ADC value of 1.19×10⁻³ mm²/s.
Abbreviation: ADC, apparent diffusion coefficient.

Figure 3 A 48-year-old male with a pathologically proven, grade 2 neuroendocrine tumor in the pancreatic tail.

Notes: On T1- (A) and T2 (B)-weighted imaging, the tumor showed hypointensity and iso- to hyperintensity, respectively. On diffusion-weighted imaging (C), the lesions showed high signal. The tumor was moderate heterogeneously enhanced in the arterial phase (D) and portal phase (E). ADC maps (F) showed an ADC value of 0.96×10⁻³ mm²/s. The tumor (arrow) is shown and oval shapes are the region of interest (ROi) for ADC measurement.
Abbreviation: ADC, apparent diffusion coefficient.

Figure 4 A 32-year-old male with a pathologically proven, grade 3 neuroendocrine carcinoma in the pancreatic head.

Notes: On T1- (A) and T2 (B)-weighted imaging, the tumor showed isointensity and hypointensity, respectively. On diffusion-weighted imaging (C), the lesions showed high signal. The tumor was slightly heterogeneously enhanced in the arterial phase (D) and portal phase (E). ADC maps (F) showed an ADC value of 0.84×10⁻³ mm²/s. The tumor (arrow) is shown and oval shapes are the region of interest (ROI) for ADC measurement.
Abbreviation: ADC, apparent diffusion coefficient.

Figure 5 ADC values of normal pancreatic parenchyma, PanNETs G1/G2 and PanNEC G3.

Notes: Significant differences in mean ADC value were observed between normal pancreatic parenchyma and G1/G2 tumors and PanNEC G3. in addition, mean ADC value of PanNEC G3 was also significantly lower than that of PanNET G1/G2. *P<0.0I compared with normal pancreatic parenchyma and PanNETs G1/G2.
Abbreviations: ADC, apparent diffusion coefficient; PanNETs G1/G2, grade 1/2 pancreatic neuroendocrine tumors; PanNEC G3, pancreatic neuroendocrine carcinoma G3.

Table 2 The summary of MRI findings

MR findings	Tumor grade		P-value
	PanNETs G1/G2 (n=47)	PanNEC G3 (n=12)
Boundary			<0.05
Well-circumscribed	43	7
Ill-defined	4	5
Solid and cystic pattern			<0.05
Predominant solid	37	5
Cystic-solid	10	7
MRI enhancement			>0.05
Homogeneous	12	4
Heterogeneous	35	8
Enhancement degree (arterial phase)			<0.05
Marked enhancement	39	5
Low to moderate enhancement	8	7
MRI signal of tumor
TIWI			>0.05
Isointense	9	3
Hypointense	38	9
T2WI			>0.05
Isointense	8	3
Hyperintense	39	9
DWI			<0.05
Moderate hyperintense	33	1
Marked hyperintense	14	11
Pancreatic duct dilatation	5	8	<0.05
Metastases	3	8	<0.05
Size (cm)	2.5± 1.7 (0.8–9.0)	5.3±4.9 (2.0–19)	0.001

Abbreviations: MRI, magnetic resonance imaging; PanNETs, pancreatic neuroendocrine tumors; DWI, diffusion-weighted imaging; PanNEC G3, pancreatic neuroendocrine carcinoma G3.

Figure 6 ROC curves of the mean ADC value and tumor size for differentiating PanNETs G1/G2 from PanNEC G3.

Note: The area under the curve is 0.90 and 0.82, respectively.
Abbreviations: ROC, receiver operating characteristic; ADC, apparent diffusion coefficient; PanNETs, pancreatic neuroendocrine tumors; PanNEC G3, pancreatic neuroendocrine carcinoma G3.

Table 3 Sensitivity and specificity of MR findings and ADC value for differentiating grade 3 from grade 1/2 pancreatic neuroendocrine tumors

MR findings	Sensitivity (%)	Specificity (%)	AUC
Size (<2.0 cm)	60.5	100	0.82
Pancreatic duct dilatation	91.5	33.3	0.62
Metastases	91.5	50.0	0.71
ADC value	72.3	93.3	0.90

Abbreviations: MR, magnetic resonance; ADC, apparent diffusion coefficient; AUC, area under curve.

Table 4 Correlation analysis between MRI findings and histological features

Variables	Size	PDD	Ki-67	Metastases	ADC	Mitoses count
Age (years)	0.0	−0.015	0.017	0.100	0.022	−0.059
Size		0.627**	0.550**	0.340*	−0.249	0.501**
PDD			0.574**	0.477**	−0.218	0.596**
Ki-67				0.524**	−0.409**	0.868**
Metastases					−0.205	0.552**
ADC						−0.465**

Notes:

* P<0.05;

** P<0.0l.

Abbreviations: MRI, magnetic resonance imaging; PDD, pancreatic duct dilatation; ADC, apparent diffusion coefficient.

Table 5 ORs for the associations between MRI findings and PanNEN grade (G3 vs GI/G2)

Variables	OR	95.0% CI	P-value
PDD (yes vs no)	14.0	0.925–213.0	0.06
Metastases (yes vs no)	17.5	1.47–206.9	0.03
Size (>2.0 cm)	1.26	0.45–10.9	0.35
ADC (<0.95×10^−3 mm^2/s)	31.7	2.06–487.8	0.02

Abbreviations: OR, odds ratio; MRI, magnetic resonance imaging; PanNEN, pancreatic neuroendocrine neoplasm; PDD, pancreatic duct dilatation; ADC, apparent diffusion coefficient.