Future of the Renal Biopsy: Time to Change the Conventional Modality Using Nanotechnology

Table 4

Advantages and disadvantages of small numbers of available imaging modalities.

Method	Some advantages	Some disadvantages	Readiness for clinical use [8]	Acquisition time	Penetration depth	Resolution	Integrating capacity with conventional endoscopes
Photo acoustic microscopy	(1) It can provide deep, high resolution optical images of internal organs [107].; (2) Minimize the motion artifacts [106].; (3) Provide not only anatomical/structural but also functional and molecular contrast [107].; (4) It has the capability of two- and three-dimensional reconstruction of the acquired images [111].	(1) It is unable to image dynamic processes in living tissue [112].	Yes	Several minutes [112]	2–5 cm [107, 113]	Axial resolution of 15 μm [114]; Lateral resolution of 45 μm [114]	Yes [115]
Optical coherence tomographic (OCT)	(1) It can enables high resolution depth imaging using low coherence interferometry [116].; (2) It has the capability of two- and three-dimensional reconstruction of the acquired images [117].; (3) It can function as a type of “optical biopsy” [5, 118].; (4) OCT can distinguish tissue types in kidney based on attenuation coefficient [119].; (5) Polarization-sensitive OCT has deeper penetration depth compared to OCT [120].	(1) It cannot provide imaging of deep tissue [5].	Yes	1–3 seconds [121, 122]	1 to 2 mm [117]	Axial resolutions of 1–10 μm [118]	Yes [118, 123]
Raman spectroscopy	(1) Integration with OCT; Raman spectroscopy provides an objective histopathological diagnosis [120].	(1) It is sensitive to tissue movement [120].	Yes	Several minutes [120]	Several millimeters [124]	Undefined resolution [124]	Yes [125]
Ultrasound biomicroscopy (UBM)	(1) It is actually better suited to whole embryo imaging than OCT [126].; (2) Ultrasound biomicroscopy has a resolution 5 to 10 times that of a 10-MHz ultrasound probe [127].	(1) Low resolution [126].	Yes	Acquire real time images [128].	~5 mm [129].	In vivo lateral resolution of 50 μm [129].; In vivo axial approaching 25 μm [129]	Yes [129]
Confocal laser scanning microscopy (confocal microscopy)	(1) In vivo three-dimensional imaging [130].; (2) It can record multiple sectional images of microobjects via their depth direction [131].	(1) Confocal microscopy cannot replace UBM in making specific diagnosis [132].	Yes	Few seconds [133]	Few hundred microns [126]	~0.2 μm [134]	Yes [8]
Narrow band imaging (NBI)	(1) NBI can improve visualization of tumors and vessels [135].; (2) There is no need for an intravesical dye [135].	(1) Limited view [136]	Yes	Several minutes [136]	Blue 170 μm; Green 240 μm; [104]	High [135]	Yes [104]