Indian J Med Microbiol Close
 

Figure 4: (a-f) TCCD demonstrates sequential changes in peak systolic velocity and end-diastolic velocity when intracranial pressure is severely raised six types of waveforms are noted. All these waveform are consistent with loss of cerebral autoregulation in maintaining cerebral perfusion. (a) Peak systolic velocity is increased and end-diastolic velocity reduced to <12 cm/s (topmost row) with intermittent flow reversal (middle row) - Pattern I - sharp wave with or without flow reversal. (b) Peak systolic velocity is in normal range with flow reversal in diastolic phase - Pattern II - systolic spike with flow reversal (bottom row). (c) Peak systolic velocity is reduced and diastolic wave shows reverse flow and continuity between waveforms is lost (decoupling) - Pattern III - systolic and diastolic spike. (d) Prolonged systolic acceleration with diminished amplitude with total absence of diastolic flow Pattern IV - tardus parvus waveform. (e) Peak systolic velocity is decreased with discontinuity of waveform Pattern V - systolic spike with absent diastolic. (f) Total absence of systolic and diastolic flow Pattern VI - no flow waveform

Figure 4: (a-f) TCCD demonstrates sequential changes in peak systolic velocity and end-diastolic velocity when intracranial pressure is severely raised six types of waveforms are noted. All these waveform are consistent with loss of cerebral autoregulation in maintaining cerebral perfusion. (a) Peak systolic velocity is increased and end-diastolic velocity reduced to <12 cm/s (topmost row) with intermittent flow reversal (middle row) - Pattern I - sharp wave with or without flow reversal. (b) Peak systolic velocity is in normal range with flow reversal in diastolic phase - Pattern II - systolic spike with flow reversal (bottom row). (c) Peak systolic velocity is reduced and diastolic wave shows reverse flow and continuity between waveforms is lost (decoupling) - Pattern III - systolic and diastolic spike. (d) Prolonged systolic acceleration with diminished amplitude with total absence of diastolic flow Pattern IV - tardus parvus waveform. (e) Peak systolic velocity is decreased with discontinuity of waveform Pattern V - systolic spike with absent diastolic. (f) Total absence of systolic and diastolic flow Pattern VI - no flow waveform