An international team led by Hao Zhang of Northwestern University (USA) has recently produced a multimodal imaging system that combines scanning laser ophthalmoscopy, fluorescein angiography, optical coherence tomography, and photoacoustic ophthalmoscopy into a single imaging system to provide optical absorption, optical scattering, and fluorescence properties of the retina.
Zhang and co-authors of an article published in a special section on photoacoustic imaging and sensing in the Journal of Biomedical Optics used the new imaging platform to demonstrate high-quality in vivo images acquired from both albino and pigmented rat eyes. The demonstration showed the usefulness of the complementary optical contrasts to provide comprehensive anatomic images of the retina.
Such multimodal imaging systems hold promise for both fundamental investigation and clinical diagnosis of several blinding diseases such as glaucoma.
In vivo multimodal retinal imaging of an albino rat when the scanning-laser ophthalmoscope (SLO) worked in the reflection mode. Panels are photoacoustic ophthalmoscopy (PAOM) fundus images showing retinal (RV) and choroidal (CV) vessels (left); reflection-SLO images (middle); and en face spectral-domain optical coherence tomography (SD-OCT) (right).
Zhang is assistant professor of biomedical engineering at North-western and director of the Functional Optical Imaging Lab there.
Co-authors of “Integrating photoacoustic ophthalmoscopy with scanning laser ophthalmoscopy, optical coherence tomography, and fluorescein angiography for a multimodal retinal imaging platform,” include Wei Song of Northwestern and Harbin Institute of Technology (China); Qing Wei, Tan Lieu, and David Kuai of Northwestern; Janice M. Burke of Medical College of Wisconsin (USA); and SPIE member Shuliang Jiao of University of Southern California (USA).
Source: Journal of Biomedical Optics 17(6), 061206 (2012); doi:10.1117/1.JBO.17.6.061206 (ow.ly/fiHUL).
– Ruikang Wang, member of the Journal of Biomedical Optics editorial board, recommended this paper.
SHG microscopy used to study link between cancer and tissue fiber
A pilot study of a new laser-imaging tool has shown promise for accurately analyzing distinctive fiber patterns in breast-tumor tissue to determine if the cancer has spread.
Writing in the Journal of Biomedical Optics, researchers at Johns Hopkins say their preliminary study involving 14 women with aggressive breast cancer has found a relationship between lymph-node metastasis and fiber texture and density in human breast cancers using second-harmonic-generation (SHG) microscopy.
If these “proof-of-principle” findings hold up in testing in hundreds more women with or without metastatic breast cancer, the new tool could potentially be used with other tests to more accurately determine the need for lymph node biopsy and removal in women at risk of metastatic breast cancer.
“Our new diagnostic technique has the potential to help reassure thousands of breast cancer patients that their cancers have not spread to other organs,” according to senior investigator Kristine Glunde, an associate professor at Johns Hopkins University School of Medicine (USA). The SHG technique could help people “avoid the risks and pain currently involved in direct inspections of lymph nodes for the presence of cancerous cells,” she says.
Cancer imaging experts have known for years that fibrous connective tissue located between cancer cells changes and bunches together as tumors grow and disease spreads, says study co-investigator and Johns Hopkins professor Zaver Bhujwalla.
“Until now, however, we had no proof in principle that such minute and progressive changes outside cancer cells, in the tumor micro-environment or extracellular matrix, could be measured and potentially used to better guide our staging and treatment decisions,” Bhujwalla says.
Other authors of the paper, “Collagen I fiber density increases in lymph-node-positive breast cancers: pilot study,” are Samata M. Kakkad, Meiyappan Solaiyappan, Pedram Argani, Saraswati Sukumar, Lisa K. Jacobs, and Dieter Leibfritz.
Source: Journal of Biomedical Optics 17(11), 116017 (2012); doi:10.1117/1.JBO.17.11.116017 (ow.ly/fkz8N).