Keywords:
Abdomen, Pancreas, MR, Contrast agent-intravenous, Pathology, Neoplasia
Authors:
F. Castelli, R. Negrelli, L. Zantedeschi, A. Ventriglia, R. Manfredi, R. Pozzi Mucelli; Verona/IT
DOI:
10.1594/ecr2012/C-1200
Results
OBSERVATIONS AT DIAGNOSIS
Qualitative image analysis
- Anatomical malformations of the pancreatic ductal system: the presence of pancreas divisum was observed in 2/37 (5,4%) patients.
- Site of pancreatic lesions and signal intensity of the parenchima: signal intensity abnormalities and focal enlargement of pancreatic parenchyma was localized in the head in 18/37 (48,6%) cases and in the body-tail in 19/37 (51,4%) patients (Table 2).
- Contrast enhancement of pancreatic parenchyma: the lesion appeared hypointense in T1-weighted images and lightly hyperintense in T2-weighted images in all cases; thus,
after contrast fluid administration,
the lesion showed poor enhancement during pancreatic phase and delayed contrast enhancement during portal venous and delayed phases.
- Type of stenosis of the MPD: MRCP sequences showed a complete stenosis in 30/37 (81%) patients and a thread-like narrowing in 7/37 (19%) cases.
- Dilation of the side branches: dilation of side branches was observed in 17/37 (46%) patients,
whereas in the remaining 20/37 (54%) patients the caliber of the MPD was normal.
- “Duct penetrating sign”: after secretin administration the duct penetrating sign was observed in 15/37 (40,5%) patients.
Quantitative image analysis
- Number of stenoses of the MPD: a single stenosis was observed in 27/37 (73%) patients,
2 stenoses in 8/37 (21,6%),
3 in 1/37 (2,7%) and 4 in 1/37 (2,7%) cases.
- Length of the MPD stricture: the mean length of the MPD narrowing was 13,5 mm (median 13mm; range 4,5-30 mm).
- Upstream dilation: the caliber of the MPD upstream the lesion was 3,9 mm (median 3,7 mm; range 0-7,5 mm).
OBSERVATIONS AFTER STEROID TREATMENT
Qualitative image analysis
- Image analysis showed a complete return to the normal size of the gland in 12/37 (32,5%) patients,
a reduction/atrophy of the parenchyma in 16/37 (43,2%) patients,
a recurrence of the disease in 5/37 (13,5%) cases and finally 4/37 (10,8%) patients underwent surgery (Fig. 8).
- 33 patients were treated with corticosteroid; 21/33 (63,6%)of these showed a normalization of T1-weighted images,
whereas only 12/33 (36,4%) patients showed a signal inhomogeneity due to the fibrosis of the parenchyma.
After contrast fluid administration 25/33 (75,8%) cases showed a normal vascularization while in 8/33 (24,2%) patients the parenchyma was hypo-vascular.
- MRCP images showed a complete resolution of the stricture in 20/33 (60,6%) patients.
This result compared with the findings at time of diagnosis was statistically significant (p<0,01) (Fig. 9).
- In MRCP images we found that 8/37 (21,6%) patients showed a thread-like stenosis,
5/37 (13,5%) a complete stricture and 24/37 (64,9%) showed no narrowing of the MPD.
The difference between these values and the findings at time of diagnosis was not statistically significant (Table 3).
- Dilation of the side branches was observed in only 5/37 (13,5%) patients,
showing a reduction statistically significant (p<0,01).
- The duct penetrating sign was observed in 7/37 (19%) patients.
This data was not statistically significant.
Qualitative imaging findings are summarized in Table 4.
Quantitative image analysis
- After steroid treatment the mean number of the stenoses of the MPD was 0,43 (median 0; range 0-3),
showing a reduction statistically significant (p<0,01).
- The mean length of the MPD stricture was 3 mm (median 0 mm; range 0-25 mm); again,
the difference resulted significant (p<0,01).
- The mean diameter of the upstream dilation of the MPD was 1 mm (median 0 mm; range 0-4,6 mm); this reduction was statistically significant (p<0,01) (Table 5).
Quantitative imaging findings are summarized in Table 6,
Table 7.
Eventually we focused on the 13 patients in which at least 1 stenosis remained after steroid treatment.
In these patients the mean number of the stenoses of the MPD was 1,23 (median 1; range 1-3),
the mean length of the MPD stricture was 8,4 mm (median 8 mm; range 1,5-25 mm) and the mean diameter of the upstream dilation of the MPD was 3 mm (median 3 mm; range 1,2-4,6 mm).
The difference between this data and the findings at time of diagnosis was statistically significant only in the reduction of the length of the stenosis (p=0,018) (Table 8,
Table 9).