For the detection and staging of breast cancer, DCE-MRI is the gold standard method, but it has many limitations as low specificity, high cost, long duration of examination time, and limited availability. CESM is considered now a relatively new imaging modality which can provide both anatomic and functional information of the breast lesion similar to DCE-MRI [12,13,14].
The advantage of contrast mammography over DCE-MRI is that it is more affordable, easier to perform and takes much less time as compared to MRI. Also, the higher sensitivity of DCE-MRI is accused by numerous false-positive foci of enhancement .
CESM can be done when there are contraindications to DCE-MRI (pacemakers, claustrophobia, etc.). It is considered an affordable, efficient, and more accessible alternative to DCE-MRI. It can be easily done in a daily workflow when conventional digital mammography and ultrasound are inconclusive for suspicious findings .
One of the limitations of CESM is that it does not provide the possibility of enhancement kinetic analyses like DCE-MRI .
In our study, DCE-MRI has a higher sensitivity (100%) for the detection of intraductal papilloma as compared to the sensitivity of CESM (64.9%) regardless of the size of the lesion. However, DCE-MRI has a lower specificity of 37.5% as compared to the specificity of CESM (50%).
When we sub-grouped the cases according to the size of the lesion, we found that DCE-MRI sensitivity is high in all groups (100%), while its specificity became less when the size of the lesion was smaller and was 0% when the size of the lesion was less than 5 mm.
On the other hand, the sensitivity of CESM was higher when the size of the lesion was more than 10 mm (90.1%) with low specificity (0%). For lesions between 5 and 10 mm, the sensitivity of CESM became less (63.6%) and its specificity was higher (50%).
In lesions less than 5mm, CESM did not detect any intraductal lesion with the sensitivity 0% and its specificity 100%.
Previously published studies compared CESM and DCE-MRI in breast cancer or BIRADS 4 lesions [12, 14, 16, 17], with no previous study done on the comparison between both CESM and DCE-MRI in intraductal papilloma.
Jochelson et al. did a prospective study and concluded that CESM has a lower sensitivity and higher specificity when compared to breast MRI .
Yousefa et al. agreed with Houssami et al. . They concluded that CESM has lower sensitivity and higher specificity for cancer breast. The low specificity of breast MRI led to further un-necessary work-up and unindicated biopsies .
DCE-MRI has been useful in the diagnosis of breast tumors. Previous studies have found that enhancement intensities measured 2 min after contrast administration are significantly higher in malignant than benign lesions . Some authors reported that the enhancement of intraductal papillomas on DCE-MRI was not obvious. The initial enhancement rate was not more than 100% and in other cases was less than 10% .
In our study, the enhancement of intraductal lesions was variable on both CESM and DCE-MRI. It varied from mild to intense enhancement and from marginal to homogenous enhancement. All pathologically proven papilloma cases showed a type I (28/37cases; 75%) and type II (7/37 cases; 20%) dynamic curves while lesions giving a type III curve (2/37 cases; 5%); proved to be associated with another underlying pathology; granulomatous mastitis in one case and inflammatory changes in another.
Zhu et al.  noted that rapid initial enhancement was seen in both intraductal papillomas and invasive carcinomas, but the early-phase enhancement rate of intraductal papilloma was significantly lower than that of invasive carcinomas (p < 0.05). The fibrovascular bundle structure of intraductal papilloma might provide the histologic explanation for the uptake of contrast material . The time-intensity curve is an important criterion to distinguish between patterns of enhancement of benign and malignant breast lesions [19, 21]. Washout curves are an important predictor of malignancy, whereas persistent and plateau patterns suggest benign lesions .
The reported MR enhancement patterns of intraductal papillomas are variable. Daniel et al.  studied the DCE-MRI performance of intraductal papillomas and reported that most enhancing papillomas showed a plateau curve. Krämer et al.  concluded that benign papillomas did not show patterns of enhancement suggestive of malignancy. In their study, all papillomas showed rapid initial enhancement. Additionally, 72% of intraductal papillomas and 69% of invasive cancers revealed washout curves, with no significant difference between the two groups . However, in another study, the dynamic curve of papillomas had a higher percentage of type III (washout) and no type I (progressive) delayed kinetic patterns of enhancement .
Zhu et al. showed a significant difference in the evolution of enhancement patterns in the periphery and center of intraductal papillomas versus carcinomas. They found that on DCE-MRI, most intraductal papillomas showed homogeneous or heterogeneous enhancement in the early phase and changed to rim enhancement in the delayed phase. This was scarcely seen in invasive carcinomas. This is suggested as a helpful sign in the diagnosis of intraductal papilloma of the breast .
Graziani et al. found that there is a variable morphologic appearance of benign papillomas on DCE-MRI as it can be occult lesion, “fibroadenoma-like” lesion or even “tumor-like” lesions. Also, they detected different MRI enhancement patterns, from mild, slow enhancement to early, strong, early enhancement with a plateau or a washout enhancement pattern. The kinetic curve of strongly enhancing lesion usually types 2 or 3 curves that make it very similar to malignant lesions .
In our study, since we concentrated on papilloma cases (37/45 cases; 82%), we found this pattern of marginal enhancement in (27/37 cases;73%) of MRI detected papillomas while others (10/37 cases; 7%) showed homogenous enhancement with no ring pattern in the delayed phase. This can be attributed to the small size of an intraductal papilloma which makes it more difficult to show this pattern.
Lobbes et al. compared CESM and MRI in the assessment of the size of the breast tumor. They found that CESM is good for measuring the size of the tumor while MRI did not add to the assessment of tumor size .
In a study done by Rotha et al., the smallest enhancing lesion detected on post-contract images was a 4 mm DCIS. This lesion was identified on both CESM and BMRI .
While in another study, breast MRI and CESM were found similar in the assessment of local extent of disease, lesion size, and multifocal/multicentric involvement, but they found CESM not the optimal study for some benign lesions as intraductal papillomas, small fibroadenomas, and radial scars .
In our study, the mean size of lesions was 11.1 ± 4.6 mm on DCE-MRI and 13.8 ± 3.4 mm on CESM with statistical significance P = 0.005*(≤ 0.05) (Table 4). The smallest detected size on DCE-MRI was 4 mm.
Regarding using mass and non-mass enhancement as morphology descriptors in CESM as described by Kamal et al. in 2015 , we found this difficult in case of small lesions as intraductal papillomas especially those less than 15 mm in size. In our study, only 4 cases (4/45 cases) 9% showed a well-defined mass enhancement on CESM even when MRI showed a well-defined enhancing nodule; of these, two were benign intraductal papillomas of size 15 mm, one was invasive ductal carcinoma, and the fourth was papillary cystic carcinoma. In our study, of all the 37 papillomas diagnosed on histopathology, only 20 showed contrast enhancement (54%) on CESM of which 18 cases (49%) showed non-mass enhancement either focal or ductal distribution. This may be attributed to the small size of the lesions; however, all papilloma cases showing regional or segmental enhancement on CESM proved to be associated with an underlying pathology; granulomatous mastitis in one case and inflammatory changes in another.