By Dr R Sinha and Dr F Singh - The Royal College of Radiologists · 2017. 9. 10. · By Dr R Sinha...

Discussion and Conclusions

Breast augmentation is the most common cosmetic procedure in the

UK and numbers are increasing year on year.

Implant rupture is a frequent indication for removal of implants, the

incidence of implant rupture increasing with implant age.

MRI is the gold standard investigation for imaging implant rupture and

there is little data in the literature with regards to accuracy of

ultrasound in detecting rupture.

After implantation of a breast implant, a fibrous capsule (scar) forms

around the implant shell.

On ultrasound, a normal implant is anechoic, the implant shell has a

thin echogenic line and a small amount of peri-implant fluid is

acceptable (Figure 1).

Free silicon has a characteristic heterogeneous echogenic snowstorm

appearance (Figure 2).

Figure 3 demonstrates the silicon specific sequences used in MRI

breast protocols.

On MRI, rupture is demonstrated as collapse of the implant shell and

free silicon outside the implant (figure 4).

Methods

Ultrasound Breast Implant Rupture- How accurate are we? By Dr R Sinha and Dr F Singh

Radiology Department Royal Albert Edward Infirmary, Wigan, UK.

Only one case of rupture was missed on ultrasound, however the

diagnosis was made on MRI.

However, this was a subtle intra capsular rupture, unlikely to have

require surgical intervention.

Our recommendation is that ultrasound should be the first line of

investigation for implant rupture.

If a rupture is identified on ultrasound, then the patient can go on to

have an MRI for confirmation.

We hope this study increases our surgical colleagues confidence in

excluding implant rupture by ultrasound and reducing the need for

performing additional MRI.

1. Appropriate use of magnetic resonance imaging and ultrasound to

detect early silicone gel breast implant rupture in postmastectomy

reconstruction. Rietjens M et al. Plast Reconstr Surg. 2014

Jul;134(1):13e-20e.

2. Imaging of breast implants-a pictorial review. Juanpere S et al. Insights

Imaging. 2011 Dec;2(6):653-670. Epub 2011 Aug 7.

3. Imaging of common breast implants and implant-related

complications: A pictorial essay. Indian J Radiol Imaging. 2016 Apr-

Jun; 26(2): 216–225

MRI - Rupture MRI - No rupture

US - Rupture 15 (true positives) 16 (false positives)

US - No rupture 1 (false negative) 47 (true negatives)

References

Figure 1 – Normal ultrasound image of breast implant

Figure 2 – typical snowstorm appearance of free silicon

Table 1 – demonstrates the true and false positives and negatives used to derive the statistics.

Patients who underwent initial ultrasound followed by MRI breasts

(implant protocol) between March 2014 and November 2015 were

included in the study.

Patient demographics, presenting complaint and presence or absence

of implant rupture for each modality was documented.

Background

The aim of this study is to evaluate the accuracy of investigating

implant rupture on ultrasound in comparison to MRI.

Figure 4: Intra capsular rupture - the shells are collapsed and there is increased fluid around the implants.

Figure 3: Normal MRI of the implants – with silicon specific (top) and silicon saturated (bottom) sequences.

46 patients were included in the study with a total of 79 implants

imaged by US and MRI. The presenting complaint varied between

pain, change in shape and lump.

MRI detected a 20% (16/79) rupture rate.

15 of these ruptures were detected by ultrasound, giving rupture

detection by ultrasound (in comparison to MRI as gold standard):

Sensitivity of 94%

Specificity 75%

Positive predictive value 48%

Negative predictive value of 98%.

Table 1 displays the results from which the statistics were derived.

Results

Aim