Can the MTI04Cx amplify currents of few pA to few nA and how great is the noise in A/(Hz^1/2)?
 
Experiences of projects have shown that the simulations are conform well to practical measurements. A few values for the equivalent input noise by certain transimpedances (all values are simulation values!!! -  rmsNoise) are shown beneath:

20MOhm   < 25pA/(Hz^1/2)
10MOhm   < 50pA/(Hz^1/2)
  5MOhm   < 80pA/(Hz^1/2)
  2MOhm   < 160pA/(Hz^1/2)
  1MOhm   < 280pA/(Hz^1/2)
500kOhm  < 500pA/(Hz^1/2)
100kOhm  < 1650pA/(Hz^1/2)
  25kOhm   < 5500pA/(Hz^1/2)

The supply voltage and the reference voltage at Vref have an important role.