instruction: count the number of patients that received a mri - head procedure in the same hospital visit after having received a normal saline administration - fluid bolus (250-1000mls) procedure in 2101.
response: SELECT COUNT(DISTINCT t1.uniquepid) FROM (SELECT patient.uniquepid, treatment.treatmenttime, patient.patienthealthsystemstayid FROM treatment JOIN patient ON treatment.patientunitstayid = patient.patientunitstayid WHERE treatment.treatmentname = 'normal saline administration - fluid bolus (250-1000mls)' AND STRFTIME('%y', treatment.treatmenttime) = '2101') AS t1 JOIN (SELECT patient.uniquepid, treatment.treatmenttime, patient.patienthealthsystemstayid FROM treatment JOIN patient ON treatment.patientunitstayid = patient.patientunitstayid WHERE treatment.treatmentname = 'mri - head' AND STRFTIME('%y', treatment.treatmenttime) = '2101') AS t2 WHERE t1.treatmenttime < t2.treatmenttime AND t1.patienthealthsystemstayid = t2.patienthealthsystemstayid