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A minimally invasive lens-free computational microendoscope.

ABSTRACT: Ultra-miniaturized microendoscopes are vital for numerous biomedical applications. Such minimally invasive imagers allow for navigation into hard-to-reach regions and observation of deep brain activity in freely moving animals. Conventional solutions use distal microlenses. However, as lenses become smaller and less invasive, they develop greater aberrations and restricted fields of view. In addition, most of the imagers capable of variable focusing require mechanical actuation of the lens, increasing the distal complexity and weight. Here, we demonstrate a distal lens-free approach to microendoscopy enabled by computational image recovery. Our approach is entirely actuation free and uses a single pseudorandom spatial mask at the distal end of a multicore fiber. Experimentally, this lensless approach increases the space-bandwidth product, i.e., field of view divided by resolution, by threefold over a best-case lens-based system. In addition, the microendoscope demonstrates color resolved imaging and refocusing to 11 distinct depth planes from a single camera frame without any actuated parts.

SUBMITTER: Shin J

PROVIDER: S-EPMC6897551 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

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A minimally invasive lens-free computational microendoscope.

Shin Jaewook J Tran Dung N DN Stroud Jasper R JR Chin Sang S Tran Trac D TD Foster Mark A MA

Science advances 20191206 12

Ultra-miniaturized microendoscopes are vital for numerous biomedical applications. Such minimally invasive imagers allow for navigation into hard-to-reach regions and observation of deep brain activity in freely moving animals. Conventional solutions use distal microlenses. However, as lenses become smaller and less invasive, they develop greater aberrations and restricted fields of view. In addition, most of the imagers capable of variable focusing require mechanical actuation of the lens, incr ...[more]

PMID: 31840055

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Project description:Minimally invasive esophagectomy is increasingly performed for the treatment of esophageal cancer, but it is unclear whether hybrid minimally invasive esophagectomy (HMIE) or totally minimally invasive esophagectomy (TMIE) should be preferred. The objective of this study was to perform a meta-analysis of studies comparing HMIE with TMIE. A systematic literature search was performed in MEDLINE, Embase, and the Cochrane Library. Articles comparing HMIE and TMIE were included. The Newcastle-Ottawa scale was used for critical appraisal of methodological quality. The primary outcome was pneumonia. Sensitivity analysis was performed by analyzing outcome for open chest hybrid MIE versus total TMIE and open abdomen MIE versus TMIE separately. Therefore, subgroup analysis was performed for laparoscopy-assisted HMIE versus TMIE, thoracoscopy-assisted HMIE versus TMIE, Ivor Lewis HMIE versus Ivor Lewis TMIE, and McKeown HMIE versus McKeown TMIE. There were no randomized controlled trials. Twenty-nine studies with a total of 3732 patients were included. Studies had a low to moderate risk of bias. In the main analysis, the pooled incidence of pneumonia was 19.0% after HMIE and 9.8% after TMIE which was not significantly different between the groups (RR: 1.46, 95% CI: 0.97-2.20). TMIE was associated with a lower incidence of wound infections (RR: 1.81, 95% CI: 1.13-2.90) and less blood loss (SMD: 0.78, 95% CI: 0.34-1.22) but with longer operative time (SMD:-0.33, 95% CI: -0.59--0.08). In subgroup analysis, laparoscopy-assisted HMIE was associated with a higher lymph node count than TMIE, and Ivor Lewis HMIE was associated with a lower anastomotic leakage rate than Ivor Lewis TMIE. In general, TMIE was associated with moderately lower morbidity compared to HMIE, but randomized controlled evidence is lacking. The higher leakage rate and lower lymph node count that was found after TMIE in sensitivity analysis indicate that TMIE can also have disadvantages. The findings of this meta-analysis should be considered carefully by surgeons when moving from HMIE to TMIE.

Project description:BackgroundTraditional ureteral stricture balloon dilation was performed with fluoroscopic assistance. The use of a C-arm X-ray machine delivered hazardous radiation to both surgeons and patients. In attempt to eliminate the radiation hazard, we developed a F4.5/6.5 ureteroscope assisted intraoperative X-ray free balloon dilation surgical approach to treat ureteral stricture and to verify its safety and efficacy. Specifically, this method had not been previously reported in the literature.MethodsWe demonstrated an intraoperative X-ray free balloon dilation with detailed step-by-step procedures description and video illustration. Clinical data of patients undergoing minimally invasive endourological treatment for ureteral stricture between February 2015 and November 2019 were retrospectively analyzed. All steps of X-ray free balloon dilation were carried out under direct vision of a ureteroscope, and two indwelling F7 ureteral stents were used for 3 months postoperatively. Preoperative, intraoperative, and postoperative clinical data were evaluated, and follow-up results were reported. Successful outcome was defined as disappearance of preoperative symptoms, relief of hydronephrosis and stable of renal function. Univariate and multivariate prognostic analyses were performed.ResultsWe identified 109 patients who received endourological treatment for ureteral stricture in our hospital's medical database. After excluding patients undergone simple catheter dilation, endoureterotomy and other treatment method, 76 patients received balloon dilation without intraoperative fluoroscopic guidance were included in our study. 4/76 patients report a grade II complication (urinary tract infections, UTIs) according to Clavien Dindo classification. In the 22.5 months median follow-up time, the one-year cumulative success rate and two-year cumulative success rate were 85.9% and 80.2% (61/76), respectively, and the majority (13/15, 86.7%) recurrence of ureteral stricture or hydronephrosis deterioration were found within two years after surgery. The longer stenotic lesion length (>5 mm) or multiple ureter stenosis and compromised blood supply of ureter were significantly associated with postoperative stenosis recurrence.ConclusionsX-ray free endoscopic balloon dilation is a safe and effective procedure that could be performed on patients with ureteral stenosis.

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A minimally invasive lens-free computational microendoscope.

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A minimally invasive lens-free computational microendoscope.

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