Magnetic resonance imaging findings of carcinoma arising from anal fistula: A retrospective study in a single institution

Table 1 Patient demographics and symptoms

Item	Data
Age (yr)	59 ± 12 (31–75)
Sex	Male (n = 8); Female (n = 2)
Pathological subtypes	Mucinous adenocarcinoma (n = 8); Adenocarcinoma (n = 2); Squamous cell carcinoma (n = 0)
Clinical symptoms	Persistent fistula (n = 10); Pain (n = 5); Discharging (n = 5); Enlarging mass (n = 1); Hematochezia (n = 1)
Duration of anal fistula	≤ 10 yr (n = 4); > 10 yr (n = 6)
History of operation	Yes (n = 10); No (n = 0)

Table 2 Sequence parameters for magnetic resonance imaging in carcinoma arising from anal fistula

	1.5 T					3.0 T
	T1WI	T2WI	FS-T2WI	DWI	T1-DCE	T1WI	T2WI	FS-T2WI	DWI	T1-DCE
Imaging plane	Axial	Axial/coronal/sagittal	Axial/coronal/sagittal	Axial	Axial/coronal/sagittal	Axial	Axial/coronal/sagittal	Axial/coronal/sagittal	Axial	Axial/coronal/sagittal
TE/TR (ms)	21/658	84/2400	80/2530	95/5800	2.3/4.9	12/970	93/5600	85/3400	76/10900	1.4/4.0
Field of view (mm)	220	220	220	220	220	220	220	220	220	220
Matrix size	256/256	256/256	256/256	256/256	256/256	416/224	416/224	416/224	416/224	416/224
Slice thickness (mm)	4.0	4.0	4.0	5.0	3.0	4.0	4.0	4.0	5.0	3.0
Intersection gap (mm)	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5

T1WI: T1-weighted magnetic resonance imaging; FS-T2WI: Fat-suppressed T2-weighted magnetic resonance imaging; DWI: Diffusion-weighted imaging; DCE: Dynamic contrast enhanced.

Table 3 Summary of magnetic resonance imaging findings in carcinoma arising from anal fistula

Pathology	Location	Shape	Maximum diameter of lesion (cm)	Margin and capsule	Signal characteristics			Fistula between mass and anus	Enhancement of tumor	Enhancement and signal on FS-T2WI of peritumoral areas	Regional lymph nodes
					FS-T2WI	DWI	ADC				Short axis enlargement	Morphology	Signal intensity(FS-T2WI/DWI)	Enhancement
M	Left	Multilocular, cauliflower-like	3.6	Unclear; Yes	Markedly hyperintense	Slightly hyperintense	Hyperintense	Yes	Progressive mesh-like enhancement	No	Yes	Change	Heterogeneous; hyperintense	Yes
M	Right	Multilocular, cauliflower-like	4.7	Clear; Yes	Markedly hyperintense	Hyperintense	Local hypointense	Yes	__	__	Yes	Normal	Heterogeneous; normal	-
M	Left	Round	4.1	Unclear; No	Slightly hyperintense	__	__	Yes	__	__	Yes	Change	Heterogeneous; -	-
M	Across the midline	Multilocular, cauliflower-like	10.6	Unclear; Yes	Markedly hyperintense	__	__	Yes	__	__	Yes	Change	Heterogeneous; -	-
M	Left	Multilocular, cauliflower-like	12.4	Unclear; Yes	Markedly hyperintense	__	__	Yes	__	__	No	Change	Heterogeneous-us; -	-
M	Left	Band-like	3.4	Unclear; No	Hyperintense	__	__	Yes	__	__	No	Change	Heterogeneous-us; -	-
M	Left	Multilocular, cauliflower-like	4.3	Unclear; Yes	Markedly hyperintense	Hyperintense	Local hypointense	Yes	Progressive mesh-like enhancement	Yes	No	Normal	Normal; normal	No
M	Across the midline	Multilocular, cauliflower-like	6.0	Unclear; Yes	Markedly hyperintense	Hyperintense	Local hypointense	Yes	Progressive mesh-like enhancement	Yes	No	Normal	Heterogeneous-us; normal	No
A	Left	Oval	3.7	Unclear; No	Slightly hyperintense	Hyperintense	Hypointense	No	Persistent heterogeneous enhancement	Yes	Yes	Change	Heterogeneous-us; hyperintense	Yes
A	Right	Oval	4.0	Unclear; Yes	Hyperintense	__	__	Yes	Persistent heterogeneous enhancement	Yes	Yes	Change	Heterogeneous-us; -	Yes

FS-T2WI: Fat-suppressed T2-weighted magnetic resonance imaging; DWI: Diffusion-weighted imaging; ADC: Apparent diffusion coefficient; M: Mucinous adenocarcinoma; A: Adenocarcinoma.