by dr r sinha and dr f singh - the royal college of radiologists · 2017. 9. 10. · by dr r sinha...
TRANSCRIPT
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