Table 1.
Techniques for vessel detection during stereotactic brain biopsies.
| Author, year | Technique | Clinical data | Main findings | Limitations | Safety |
|---|---|---|---|---|---|
| FLUORESCENT CONTRAST DETECTION | |||||
| Göbel et al. (22) | 1.5-mm-diameter multifiber forward-viewing needle endoscope for dual fluorescence (PpIX, ICG) and autofluorescence imaging. Results in multicolor images. | Pilot clinical trial (n = 1) showed feasibility of autofluorescence and PpIX visualization; however, safety, and vessel detection were not evaluated. | Established feasibility on phantom and characterized detection capability of the vessels, normal brain, and viable tumor tissue. | Forward-viewing probe. | Light power was 10 mW. |
| Rühm et al. (23) | Fiber-based ICG detection in the vessels for stereotactic procedures. | No. Only computer simulation model. | Established safety corridor for excitation light power to prevent normal brain destruction. | Simulation computer model experiment. | Established light intensity safety corridor for ICG. |
| STAIN-LESS REFLECTANCE IMAGING APPROACHES | |||||
| Pichette et al. (24)Goyette et al. (25) | 24-fiber, 1.7-mm-diameter probe for interstitial sub-diffuse optical tomography. Technology is based on the spectroscopic detection of hemoglobin remittance and sub-diffused light spectra. Creates a 2D map visualizing potential locations of vessels and their proximity to the probe's tip. | No. Only preclinical study on phantom models. | Established feasibility and characterized detection capability of the vessels of various locations and sizes. | Extravascular blood could affect interpretation of the data. Complex probe design. | N/R. |
| Markwardt et al. (26) | Double fiber-based probe inserted in biopsy needle for hemoglobin remission spectrometry. Allows detection of proximity and size of blood vessels. | No. Only preclinical study on phantom models. | Established feasibility and characterized detection capability of the vessels of various locations and sizes. | Extravascular blood could affect interpretation of the data. | Light power intensity below MPE for the skin of 2 kW/m2. |
| Ramakonar et al. (27) | Side-viewing fiber OCT probe fitting the standard brain biopsy needle with automatic vessel detection on B-imaging mode. | Pilot clinical trial (n = 11) demonstrated feasibility of automatic vessel detection. | Established feasibility and characterized detection capability of the vessels. | No forward viewing. | N/R, although considered safe based on the patient data. |
| LASER DOPPLER FLOWMETRY | |||||
| Haj-Hosseini et al. (28) | 9-fiber, forward-viewing probe fitting the biopsy needle for simultaneous laser Doppler flowmetry and PpIX fluorescence spectral detection. | Similar probes for laser Doppler flowmetry imaging have been studied in stereotactic procedures under IRB approval in previous studies (29, 30). | Established feasibility and characterized brain perfusion along the biopsy needle trajectory. | No side viewing. | Light power 10 mW for PpIX excitation. |
ICG, indocyanine green; N/R, not reported; PpIX, protoporphyrin IX; ICG, indocyanine green; OCT, optical coherence tomography; MPE, maximal permissible exposure.