MolecuLight i:X for wound imaging

Study size, design and location

A single-centre prospective observational study in the UK of 14 patients (with a total of 17 wounds) presenting to outpatient dressings clinics.

Intervention and comparator(s)

Intervention: MolecuLight i:X imaging device.

Comparator: clinical signs and symptoms of infection (CSS), microbiological swabs.

Key outcomes

Out of 17 wounds, 8 were positive for bacterial growth on microbiological culture and all 8 were positive for bacteria according to fluorescence imaging. One wound was positive for bacteria by fluorescence imaging with negative microbiological results and CSS. Three patients did not complain of, or display CSS, but fluorescence photos and swab results confirmed bacterial growth. All 6 patients that did exhibit CSS had photos and swab results confirming positive bacterial growth.

Strengths and limitations

A UK-based study that is generalisable to the NHS. A single-centre observational study gives low-quality evidence. Small sample size, which limits the reliability of results. Limited reporting of outcomes with no statistical analysis of results.

Study size, design and location

A pilot study in the UK of 20 patients with burn wounds presenting between April and July 2016.

Intervention and comparator(s)

Intervention: MolecuLight i:X imaging device.

Comparator: CSS of infection, microbiology swabs.

Key outcomes

Out of 20 patients, 16 (80%) showed growth of bacteria in swabs and MolecuLight i:X imaging.

Two patients did not have CSS but images and swabs showed bacterial presence and 1 patient had CSS when the images and swabs were negative.

Strengths and limitations

UK-based study that is generalisable to the NHS. A single-centre study limits the reliability of findings. No statistical analysis of results. There is a good range of outcomes, including which antimicrobial intervention was given.

Study size, design and location

A single-centre observational study in the UK of 31 patients (with a total of 35 wounds) attending a hand trauma unit over 4 weeks.

Intervention and comparator(s)

Intervention: MolecuLight i:X imaging device.

Comparator: CSS, microbiological swabs.

Key outcomes

Autofluorescence imaging correlated with clinical signs and wound swab results for 34 wounds (97.1%). In 1 case, the clinical assessment and autofluorescence imaging showed positive signs of infection but the wound swabs were negative.

Strengths and limitations

A UK-based study that is generalisable to the NHS. A single-centre study and small sample size limit the reliability of results.

Study size, design and location

A single-centre prospective observational study in Ireland of 33 patients (43 swabs) in an outpatient plastic surgery wound care clinic.

Intervention and comparator(s)

Intervention: MolecuLight i:X imaging device.

Comparator: microbiological swabs.

Key outcomes

There were 41 out of 43 swabs (95.3%) that were positive for bacterial growth. MolecuLight i:X had a sensitivity of 100% and specificity of 78% when identifying pathological bacteria presence in wounds. The positive predictive value (PPV) was 95.4% and the negative predictive value was 100%. There was a 100% sensitivity and specificity in detecting Pseudomonas spp. Overt signs of infection were identified in 7 patients, and a 1‑week course of antibiotics was prescribed. After 2 weeks, all fluorescence and microbiological swabs were negative.

Strengths and limitations

Relevant outcomes were reported. Wound types were varied which helps to show use of MolecuLight i:X for a wide range of indications. A single-centre observational study gives low-quality evidence.

Study size, design and location

A single-centre observational study in the UK of 10 children with burn wounds (total 15 wounds with 16 observations).

Intervention and comparator(s)

Intervention: MolecuLight i:X imaging device.

Comparator: CSS of infection, microbiological swabs.

Key outcomes

The presence or absence of bacterial fluorescence on images was consistent with CSS of infection in 87.5% of cases (14/16). In the other 2 cases, MolecuLight i:X images detected red (bacterial) fluorescence in the absence of any signs or symptoms, with both cases confirmed bacterial positive with swabs.

The presence or absence of bacterial fluorescence on images was consistent with culture analysis in 81% of cases (13/16) and no false negatives were detected. The remaining 3 wounds were fluorescence and CSS positive in both observations. These 3 wounds were swabbed but not targeting the area of bacterial fluorescence and so may have been missed.

Reports about using the device with children were positive. No adverse events were reported.

Strengths and limitations

A single-centre observational study gives low-quality evidence. A small sample size limits reliability of results. Most patients in the study were treated with topical antimicrobial agents before taking swabs, which may have resulted in false-negative cultures.

Study size, design and location

A non-randomised single-blind clinical trial in the US and Canada of 60 patients with chronic wounds (47 diabetic foot ulcers, 12 venous leg ulcers and 1 amputation) showing regions of red fluorescence.

The study consists of 2 arms: arm 1 was a multisite clinical trial in the US, arm 2 was a post-market clinical follow-up trial in Canada.

Intervention and comparator(s)

Intervention: MolecuLight i:X.

Comparator: quantitative polymerase chain reaction (PCR) of biopsy samples (arm 1) or semi-quantitative culture analysis of curettage samples (arm 2).

Key outcomes

In arm 1 of the study (30 wounds), PCR analysis of wound tissue biopsies from areas of red fluorescence resulted in a PPV of 100%, with a total bacterial load of 10⁴ colony-forming units (CFU)/g or higher. In arm 2 of the study (30 wounds), semi-quantitative culture analysis of curettage scrapings from regions of red fluorescence resulted in a PPV of 100%, with predominantly moderate or heavy bacterial growth.

Strengths and limitations

A sample size power calculation was performed for each arm of the study. Study included a range of different wound types, which increases reliability of results and generalisability to different wound types. The study was not done in UK and so is not generalisable to an NHS setting. The study author is an employee of the company.

Study size, design and location

A prospective, single-blind, single-centre clinical trial in the US of 19 patients (17 venous leg ulcers and 2 diabetic foot ulcers) presenting at an advanced outpatient wound research clinic.

Intervention and comparator(s)

Intervention: MolecuLight i:X.

Comparators: CSS, microbiological assessment of biopsies.

Key outcomes

MolecuLight i:X with CSS significantly improved sensitivity (22% compared with 72%) and accuracy (26% compared with 74%) for identifying wounds with moderate-to-heavy bacterial loads (10⁴ CFU/g or higher) compared with CSS alone (p=0.002). Clinicians reported that overall patient care was improved by fluorescence imaging assessment in 18 out of 19 cases (95%), including identification of wounds incorrectly diagnosed by CSS (47% of study wounds) and treatment plan modifications guided by fluorescence (73% of study wounds). Antimicrobial stewardship decisions were guided by fluorescence imaging in 47% of cases.

Strengths and limitations

A comparative study helps to compare results with standard care. There is a good range of outcomes, including consideration of antibiotic usage and management decisions. A single-centre observational study gives low-quality evidence. A small sample size limits reliability of results. Not done in the UK so not generalisable to the NHS. The trial was sponsored by the company.