Breath-hold Paradigm Research Articles

Subject-Specific Activation of Central Respiratory Centers during Breath-Holding Functional Magnetic Resonance Imaging

Background: Voluntary breath-holding (BH) triggers responses from central neural control and respiratory centers in order to restore breathing. Such responses can be observed using functional MRI (fMRI). Objectives: We used this paradigm in healthy volunteers with the view to develop a biomarker that could be used to investigate disorders of the central control of breathing at the individual patient level. Method: In 21 healthy human subjects (mean age±SD, 32.8 ± 9.9 years old), fMRI was used to determine, at both the individual and group levels, the physiological neural response to expiratory and inspiratory voluntary apneas, within respiratory control centers in the brain and brainstem. Results: Group analysis showed that expiratory BH, but not inspiratory BH, triggered activation of the pontine respiratory group and raphe nuclei at the group level, with a significant relationship between the levels of activation and drop in SpO2. Using predefined ROIs, expiratory BH, and to a lesser extent, inspiratory BH were associated with activation of most respiratory centers. The right ventrolateral nucleus of the thalamus, right pre-Bötzinger complex, right VRG, right nucleus ambiguus, and left Kölliker-Fuse-parabrachial complex were only activated during inspiratory BH. Individual analysis identified activations of cortical/subcortical and brainstem structures related to respiratory control in 19 out of 21 subjects. Conclusion: Our study shows that BH paradigm allows to reliably trigger fMRI response from brainstem and cortical areas involved in respiratory control at the individual level, suggesting that it might serve as a clinically relevant biomarker to investigate conditions associated with an altered central control of respiration.

Cerebrovascular Reactivity Mapping Using Resting-State Functional MRI in Patients With Gliomas.

Recently, a data-driven regression analysis method was developed to utilize the resting-state (rs) blood oxygenation level-dependent signal for cerebrovascular reactivity (CVR) mapping (rs-CVR), which was previously optimized by comparing with the CO2 inhalation-based method in health subjects and patients with neurovascular diseases. To investigate the agreement of rs-CVR and the CVR mapping with breath-hold MRI (bh-CVR) in patients with gliomas. Retrospective. Twenty-five patients (12 males, 13 females; mean age ± SD, 48 ± 13 years) with gliomas. Dynamic T2*-weighted gradient-echo echo-planar imaging during a breath-hold paradigm and during the rs on a 3-T scanner. rs-CVR with various frequency ranges and resting-state fluctuation amplitude (RSFA) were assessed. The agreement between each rs-based CVR measurement and bh-CVR was determined by voxel-wise correlation and Dice coefficient in the whole brain, gray matter, and the lesion region of interest (ROI). Voxel-wise Pearson correlation, Dice coefficient, Fisher Z-transformation, repeated-measure analysis of variance and post hoc test with Bonferroni correction, and nonparametric repeated-measure Friedman test and post hoc test with Bonferroni correction were used. Significance was set at P< 0.05. Compared with bh-CVR, the highest correlations were found at the frequency bands of 0.04-0.08 Hz and 0.02-0.04 Hz for rs-CVR in both whole brain and the lesion ROI. RSFA had significantly lower correlations than did rs-CVR of 0.02-0.04 Hz and a wider frequency range (0-0.1164 Hz). Significantly higher correlations and Dice coefficient were found in normal tissues than in the lesion ROI for all three methods. The optimal frequency ranges for rs-CVR are determined by comparing with bh-CVR in patients with gliomas. The rs-CVR method outperformed the RSFA. Significantly higher correlation and Dice coefficient between rs- and bh-CVR were found in normal tissue than in the lesion. 3 TECHNICAL EFFICACY STAGE: 2.

Take my breath away: Neural activation at breath-hold differentiates individuals with panic disorder from healthy controls

There is neuroanatomical evidence of an "extended fear network" of brain structures involved in the etiology of panic disorder (PD). Although ventilatory distrubance is a primary symptom of PD these sensations may also trigger onset of a panic attack (PA). Here, a voluntary breath-holding paradigm was used to mimic the hypercapnia state in order to compare blood oxygen level-dependent (BOLD) response, at the peak of a series of 18 s breath-holds, of 21 individuals with PD to 21 low anxiety matched controls. Compared to the rest condition, BOLD activity at the peak (12 - 18 s) of the breath-hold was greater for PD versus controls within a number of structures implicated in the extended fear network, including hippocampus, thalamus, and brainstem. Activation was also observed in cortical structures that are shown to be involved in interoceptive and self-referential processing, such as right insula, middle frontal gyrus, and precuneus/posterior cingulate. In lieu of amygdala activation, our findings show elevated activity throughout an extended network of cortical and subcortical structures involved in contextual, interoceptive and self-referential processing when individuals with PD engage in voluntary breath-holding.

Breath-Hold Paradigm to Assess Variations in Oxygen Flow in Diabetic Foot Ulcers Using a Noncontact Near-Infrared Optical Scanner.

Objective: Diabetic foot ulcers (DFUs) occur in almost 25% of all patients with diabetes in their lifetime, with oxygen being the key limiting factor in healing. Identifying regions of compromised oxygenated flow can help clinicians cater the wound treatment process, possibly reducing wound healing time. Herein, a handheld, noncontact near-infrared optical scanner (NIROS) was developed and used to measure temporal changes in hemoglobin concentrations in response to a breath-hold (BH) paradigm. Approach: Noncontact imaging studies were carried out on DFU subjects and control subjects in response to a 20-s BH paradigm. Continuous-wave-based multiwavelength diffused reflective signals were acquired to generate effective oxy-hemoglobin, deoxy-hemoglobin, total hemoglobin, and oxygen saturation concentration maps using modified Beer-Lambert's law. Pearson's correlation analysis was carried out to determine variations in oxygen flow from hemoglobin concentration maps and the extent of variation observed in controls versus DFU subjects. Results: Temporal changes in hemoglobin concentration maps were observed in controls and DFU subjects. However, the oxygen flow in response to BH varied within 10% in all controls but significantly varied between wound and background regions in subjects with DFUs. Innovation: A method to assess variations in oxygen supply in and around DFUs was demonstrated using NIROS. This approach has potential to better cater DFU treatment process. Conclusion: Changes in all hemoglobin parameters due to 20 s of BH was observed. Pearson's analysis indicates that oxy-hemoglobin, deoxy-hemoglobin, and oxygen saturation fluctuations are synchronous in controls. In DFUs, changes are asynchronous with blood flow between the wound region and background region being significantly different.

Dynamic Estimation of Cerebral Blood Flow Using Photoplethysmography Signal during Simulated Apnea.

Monitoring apnea-induced cerebral blood flow oscillations is of importance for assessing apnea patient brain health. Using an autoregressive moving average model, peak and trough values of cerebral blood flow were estimated from a concurrently recorded forehead photoplethysmography signal. Preliminary testing of the method in 7 subjects (4 F, 32±4 yrs., BMI 24.57±3.87 kg/m2) using a breath hold paradigm for simulating apnea shows that maximum mean and standard deviation of the prediction error is -1.10±8.49 cm/s and the maximum root mean squared of the error is 8.92 cm/s.

The Impact of Echo Time Shifts and Temporal Signal Fluctuations on BOLD Sensitivity in Presurgical Planning at 7 T.

Gradients in the static magnetic field caused by tissues with differing magnetic susceptibilities lead to regional variations in the effective echo time, which modifies both image signal and BOLD sensitivity. Local echo time changes are not considered in the most commonly used metric for BOLD sensitivity, temporal signal-to-noise ratio (tSNR), but may be significant, particularly at ultrahigh field close to air cavities (such as the sinuses and ear canals) and near gross brain pathologies and postoperative sites. We have studied the effect of local variations in echo time and tSNR on BOLD sensitivity in 3 healthy volunteers and 11 patients with tumors, postoperative cavities, and venous malformations at 7 T. Temporal signal-to-noise ratio was estimated from a 5-minute run of resting state echo planar imaging with a nominal echo time of 22 milliseconds. Maps of local echo time were derived from the phase of a multiecho GE scan. One healthy volunteer performed 10 runs of a breath-hold task. The t-map from this experiment served as a criterion standard BOLD sensitivity measure. Two runs of a less demanding breath-hold paradigm were used for patients. In all subjects, a strong reduction in the echo time (from 22 milliseconds to around 11 milliseconds) was found close to the ear canals and sinuses. These regions were characterized by high tSNR but low t-values in breath-hold t-maps. In some patients, regions of particular interest in presurgical planning were affected by reductions in the echo time to approximately 13-15 milliseconds. These included the primary motor cortex, Broca's area, and auditory cortex. These regions were characterized by high tSNR values (70 and above). Breath-hold results were corrupted by strong motion artifacts in all patients. Criterion standard BOLD sensitivity estimation using hypercapnic experiments is challenging, especially in patient populations. Taking into consideration the tSNR, commonly used for BOLD sensitivity estimation, but ignoring local reductions in the echo time (eg, from 22 to 11 milliseconds), would erroneously suggest functional sensitivity sufficient to map BOLD signal changes. It is therefore important to consider both local variations in the echo time and temporal variations in signal, using the product metric of these two indices for instance. This should ensure a reliable estimation of BOLD sensitivity and to facilitate the identification of potential false-negative results. This is particularly true at high fields, such as 7 T and in patients with large pathologies and postoperative cavities.

A vascular-task response dependency and its application in functional imaging of brain tumors

PurposePreoperative functional MRI (fMRI) is limited by a muted BOLD response caused by abnormal vasoreactivity and resultant neurovascular uncoupling adjacent to malignant brain tumors. We propose to overcome this limitation and more accurately identify eloquent areas adjacent to brain tumors by independently assessing vasoreactivity using breath-holding and incorporating these data into the fMRI analysis. MethodsLocal vasoreactivity using a breath-holding paradigm with the same timing as the functional motor and language tasks was determined in 16 patients (9 glioblastomas, 1 anaplastic astrocytoma, 5 low grade astrocytomas, and 1 metastasis) and 6 healthy control subjects. We derived an fMRI model based on an observed vaso-task response dependency that takes into account the altered hemodynamics adjacent to brain tumors. ResultsIn both healthy controls and brain tumor subjects, we found a statistical dependency between breath-hold and task BOLD response. In tumor subjects, activation maps that take into account this vaso-task dependency demonstrated clinically meaningful areas of activation that were not seen using the task-only analysis in about half of the cases studied. This included localization of language areas adjacent to brain tumors. ConclusionsThe present preliminary results demonstrate that neurovascular uncoupling known to affect the accuracy of BOLD fMRI adjacent to brain tumors may be, at least partially, overcome by incorporating an observed vaso-task dependency in the BOLD signal analysis.

Evaluation of vascular reactivity to overcome limitations of neurovascular uncoupling in BOLD fMRI of malignant brain tumors

The sensitivity of fMRI in identification of eloquent cortical centers in the case of large infiltrative growing tumors and pronounced peritumoral edema may be reduced or significantly limited in some cases. The main cause is an attenuated Blood-Oxygen-Level-Dependent response (BOLD) caused by pathological vascular reactivity and subsequent neurovascular uncoupling of fMRI. In our study, we attempted to overcome these limitations and increase the sensitivity of this technique in identification of eloquent cortical areas adjacent to brain tumors by using vasoreactivity features of a breath-holding test and including these data in the BOLD analysis. Local vasoreactivity using a breath-holding paradigm with the same block design of both motor and speech tests was determined in 5 healthy volunteers and 3 patients in the preoperative period (two patients with high grade gliomas and one patient with single metastasis). A coherence-based model was developed for analysis of BOLD fMRI, which took into account altered hemodynamics in peritumoral zones. Obtained coherence maps demonstrated clinically more significant activation zones that were not seen with standard methods of fMRI processing. Thus, neurovascular uncoupling that is known to affect the accuracy of the BOLD fMRI response adjacent to brain tumors may be partially overcome by including an independent measurement of vasoreactivity using a breath-holding test in the BOLD analysis.

Understanding the contribution of neural and physiological signal variation to the low repeatability of emotion-induced BOLD responses

Previous studies have reported low repeatability of BOLD activation measures during emotion processing tasks. It is not clear, however, whether low repeatability is a result of changes in the underlying neural signal over time, or due to insufficient reliability of the acquired BOLD signal caused by noise contamination. The aim of this study was to investigate the influence of “cleaning” the BOLD signal, by correcting for physiological noise and for differences in BOLD responsiveness, on measures of repeatability.Fifteen healthy volunteers were scanned on two different occasions, performing an emotion provocation task with faces (neutral, 50% fearful, 100% fearful) followed by a breath-hold paradigm to provide a marker of BOLD responsiveness. Repeatability of signal distribution (spatial repeatability) and repeatability of signal amplitude within two regions of interest (amygdala and fusiform gyrus) were estimated by calculating the intraclass correlation coefficient (ICC).Significant repeatability of signal amplitude was only found within the right amygdala during the perception of 50% fearful faces, but disappeared when physiological noise correction was performed. Spatial repeatability was higher within the fusiform gyrus than within the amygdala, and better at the group level than at the participant level. Neither physiological noise correction, nor consideration of BOLD responsiveness, assessed through the breath-holding, increased repeatability.The findings lead to the conclusion that low repeatability of BOLD response amplitude to emotional faces is more likely to be explained by the lack of stability in the underlying neural signal than by physiological noise contamination. Furthermore, reported repeatability might be a result of repeatability of task-correlated physiological variation rather than neural activity. This means that the emotion paradigm used in this study might not be useful for studies that require the BOLD response to be a stable measure of emotional processing, for example in the context of biomarkers.

Comparison of Cerebral Vascular Reactivity Measures Obtained Using Breath-Holding and CO2 Inhalation

Stimulation of cerebral vasculature using hypercapnia has been widely used to study cerebral vascular reactivity (CVR), which can be expressed as the quantitative change in cerebral blood flow (CBF) per mm Hg change in end-tidal partial pressure of CO2 (PETCO2). We investigate whether different respiratory manipulations, with arterial spin labeling used to measure CBF, lead to consistent measures of CVR. The approaches included: (1) an automated system delivering variable concentrations of inspired CO2 for prospective targeting of PETCO2, (2) administration of a fixed concentration of CO2 leading to subject-dependent changes in PETCO2, (3) a breath-hold (BH) paradigm with physiologic modeling of CO2 accumulation, and (4) a maneuver combining breath-hold and hyperventilation. When CVR was expressed as the percent change in CBF per mm Hg change in PETCO2, methods 1 to 3 gave consistent results. The CVR values using method 4 were significantly lower. When CVR was expressed in terms of the absolute change in CBF (mL/100 g per minute per mm Hg), greater discrepancies became apparent: methods 2 and 3 gave lower absolute CVR values compared with method 1, and the value obtained with method 4 was dramatically lower. Our findings indicate that care must be taken to ensure that CVR is measured over the linear range of the CBF-CO2 dose-response curve, avoiding hypocapnic conditions.

Vascular space occupancy MRI during breathholding at 3 tesla

To evaluate the vasodilatory response of normal human brain and meningiomas under repeated breathholding challenges using vascular space occupancy (VASO) MRI at 3 Tesla (T). Five normal volunteers and five patients with meningiomas were recruited for this study. For the normal group, VASO MRI during repeated breathholds of different duration (5 to 30 s) was acquired. Patients performed a 15-s breathhold paradigm for VASO MRI. The maximum signal change and full-width at half-maximum (FWHM) were determined by curve fitting. Significant VASO signal decreases in the gray matter could be detected for a breathhold period as short as 5 s. The fractional activation volume vs. breathhold duration reached a plateau around 34.21 ± 3.39% at 15 s. In the patient group, there were significant VASO signal decreases in normal gray matters and also in small areas of three large-sized meningiomas. The 3T VASO MRI detected significant signal decreases in the gray matter, but not in the white matter, during short periods of breathholding. The fractional activation volume reached the plateau at 15-s breathhold, which is recommended for clinical application.

Breathhold‐regulated blood oxygenation level‐dependent (BOLD) MRI of human brain at 3 tesla

To investigate the cerebrovascular response to repeated breathhold challenges using blood oxygenation level-dependent (BOLD) MRI at 3T and compare the results with previous data at 1.5T. Six normal volunteers and six patients with brain tumors were recruited for this 3T study. For the normal group, BOLD MRI during repeated breathholds of different durations (five to 30 seconds) were acquired. Maximum signal change, full-width at half-maximum (FWHM) and onset time (defined as the time to the first half-maximum) were determined by curve fitting. The fractional activation volume was also calculated. Patients performed a 10- or 15-second breathhold paradigm according to individual capability. Significant BOLD signal increases in the gray matter for a breathhold period as short as 5 seconds at 3T, instead of 10 seconds at 1.5T. The fractional activation volume vs. breathhold duration reached a plateau of 49.54 +/- 7.26% at 15 seconds at 3T, which was higher and shorter than that at 1.5T. The maximum signal changes were significantly larger (a 69% increase) at 3T than at 1.5T. In the patient group, there were BOLD signal increases in gray matter but not in tumor bulk or perifocal edema, which agreed with the results previously found at 1.5T. BOLD MRI at 3T is more sensitive for detecting breathhold-regulated signal changes than at 1.5T, which allows a shorter and more feasible breathhold paradigm for clinical applications in patients with brain tumors.

Contribution of the left and right inferior frontal gyrus in recovery from aphasia. A functional MRI study in stroke patients with preserved hemodynamic responsiveness

The relative contribution of dominant and non-dominant language networks to recovery from aphasia is a matter of debate. We assessed with functional magnetic resonance imaging (fMRI) to what extent the left and right hemispheres are associated with recovery from aphasia after stroke. fMRI with three language tasks was performed in 13 aphasic stroke patients and in 13 healthy subjects. Severity of aphasia was examined within 2 months after stroke and after at least 1 year. Recovery of naming ability and scores on the Token Test were correlated with data from fMRI in the chronic phase. A breath-hold paradigm was used to investigate hemodynamic responsiveness.Overall language performance in the chronic phase correlated with higher relative activation of left compared to right perisylvian areas. Recovery of naming ability was positively correlated with activation in the left inferior frontal gyrus (IFG) for semantic decision and verb generation. Recovery on the Token Test was positively correlated with activation in both left and right IFG during semantic decision and verb generation. Hemodynamic response to the breath-hold task was similar in patients and controls.Our study suggests that in the chronic stage after stroke left IFG activity is associated with improvement of picture naming and sentence comprehension, whereas activity in the right IFG may reflect up-regulation of non-linguistic cognitive processing. Altered hemodynamic responsiveness seems an unlikely confounder in the interpretations of fMRI results.

Change in Cerebral Perfusion after Carotid Angioplasty with Stenting Is Related to Cerebral Vasoreactivity: A Study Using Dynamic Susceptibility-Weighted Contrast-Enhanced MR Imaging and Functional MR Imaging with a Breath-Holding Paradigm

Carotid angioplasty with stent placement (CAS) is an optional treatment for significant carotid stenosis. Cerebral vasoreactivity (CVR), representing the reserve capacity of cerebral perfusion, usually decreases in patients with severe carotid stenosis. This study aimed to investigate the relationship between the baseline CVR assessed by functional MR imaging (fMRI) and the changes in cerebral blood flow (CBF) after CAS. Fourteen patients with at least 70% unilateral carotid stenosis underwent CAS. Baseline CVR was evaluated by fMRI a under breath-holding paradigm. CBF was assessed by dynamic susceptibility-weighted contrast-enhanced MR imaging before and 3-5 days after CAS. The lateral index (LI) was defined as (n - L) / (n + L), where n and L represent the number of activated voxels in fMRI on the normal and lesion hemispheres, respectively. No subject had clinical evidence of hyperperfusion syndrome. The LI represented baseline CVR. Patients were divided into normal (LI < 0, n = 6) and impaired (LI > 0, n = 8) CVR groups. The CBF on the normal and lesion sides was calculated separately. CBF increment on the lesion side after CAS was significantly higher in the impaired CVR group than that in the normal CVR group (P = .035). There was a significantly positive correlation between CVR impairment and the CBF increment (P = .026). fMRI could be a reproducible tool in evaluating CVR. After CAS, early CBF changes on the lesion side are more prominent in patients with impaired CVR. Baseline CVR might predict early CBF increase after CAS.

SU-EE-A4-05: Model-Independent Analysis of Cerebrovascular Reactivity MRI During Breath-Holding

Purpose: Both cerebral tumor and cardiovascular disease may compromise cerebrovascular reactivity due to abnormal angiogenesis or blood supply. Functional MRI during hypercapnia stress, such as breath-holding (BH), has been used to assess the cerebrovascular reactivity. However, in clinical settings, patients may not be able to hold their breath well, which can reduce the sensitivity for detection when an fMRI model-based analysis is applied. In view of the global effect induced by breath-holding, this study proposed a model-independent analysis, using the whole-brain-averaged time curve as a reference function(WBRF), and compared with the results using the canonical hrf(CHRF). Methods: T2*-weighted images were acquired using a single-shot GE EPI sequence on 1.5T MR scanner, with TR/TE=3000ms/60ms. Four experiments were performed on two normal volunteers: (1) BH after deep inspiration, (2) after an instruction, BH after the end of the natural expiration, (3) self-paced BH by button pressing and (4) take in a short breath during the BH duration. For model-independent analysis, the WBRF was the averaged time curve over the whole brain tissue. For model-dependent analysis, the CHRF was adopted from the SPM2. Voxels with statistically increased signals were determined (p<0.001), and then the fractional activation volume (activated volume/whole volume) was calculated. Results: In all cases, the WBRF was able to show the real breath-holding paradigm performed by the subjects. From the four experiments, the fractional activation volumes by model-independent analysis were 62, 53, 57, 54% and 58, 4, 5, 12% by model-dependent analysis, respectively. Conclusion: The results illustrated model-independent analysis is a more reliable approach. This is caused by the fact that WBRF better reflects the true beath-holding situation then CHRF. Due to the impaired patient performance in clinical applications, the method proposed by this study can help increasing the sensitivity of cerebovascular reactivity MRI.

Brain metabolic fluctuations in absence of stimuli

Mapping of brain function with blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) BOLD-MRI relies on the detection of focal changes in cerebral blood flow (CBF) in response to conditioned stimuli. However, in the absence of stimuli, the brain continues to show temporal fluctuations in blood flow as measured with BOLD and perfusion-based MRI (Biswal, NMR. Biomed. 1997). These fluctuations are substantially synchronized across functional regions that have an apparent functional relationship, and therefore might allow mapping and classification of the networks that underlie human brain function without the need for carefully conditioned stimuli. Despite their potential functional siginificance, the origin of the blood flow fluctuations has not been established. Potential sources include cognitive processes, fluctuations in vigilance and conscious awareness, and homeostatic (restorative) processes. Alternatively, the fluctuations might be caused by purely vascular events (e.g. vasomotor effect), without a substantial metabolic or neuronal component. In this study we used MRI methods to establish whether blood flow fluctuations in absence of stimuli subserve a metabolic process. For this purpose, we performed simultaneous BOLD and perfusion MRI at 3.0 T on 7 normal volunteers during a visual task (5 min checkerboard-grey paradigm) and an extended (25 min) rest period. The ratio between BOLD and perfusion changes was used as an indicator of metabolism (Hoge, Proc. Nat. Acad. Sci. 1999). As reference, a 10-minute breath-holding paradigm was inserted between the two conditions. The paradigm consisted of 5 stages of 40 s breath-hold, 80 s normal breathing. Physiologic monitoring included respiratory and cardiac cycles, as well as scalp potentials using a 64-channel EEG system. During rest conditions, we found substantial BOLD and perfusion signal fluctuations in most of neocortex, with strong correlations between functionally related regions. No significant correlations were found with cardiac and respiratory cycles. Frequency analysis of the fluctuations suggested that most energy was concentrated in the 0.01–0.1 Hz band. The strongest fluctuations were observed during early (non-REM) sleep, as identified from EEG. Within visual cortex (VC), the amplitude of the fluctuations reached a level similar to that evoked with the task. BOLD and perfusion signals were highly correlated over most of cortex. The ratio of their fluctuation amplitude in VC averaged 1.66(0.41), 2.82(0.70), and 1.80(0.57) for task, breath holding paradigm, and rest (sleep) respectively. The difference between task and rest was insignificant (p=0.56), while the ratios during task and rest were significantly (p=0.0003/0.017) lower than during the breath-holding paradigm. The lower ratios are indicative of a relatively high oxygen extraction, suggesting involvement of a metabolic process during task and rest, and less so during breathholding. The findings indicate that spatially correlated fluctuations in CBF in absence of stimuli have a metabolic component and continue during early sleep. This has important implication for the design of brain mapping experiments and could shed light on the physiologic processes present during of rest and sleep. Further experiments are planned to investigate a potential role of processes facilitating synaptic plasticity (Huber, Nature 2004).

Functional MRI of Human Brain during Breath Holding by BOLD and FAIR Techniques

BOLD (blood oxygenation level-dependent) and FAIR (flow-sensitive alternating inversion recovery) imaging techniques were used to investigate the oxygenation and hemodynamic responses of human brain during repeated challenges of breath holding and prolonged single breath holding. The effects of different breathing techniques on BOLD and FAIR image contrasts were carefully examined. With a periodic breath-holding paradigm of 30 s, global changes in gray matter were observable both in T*2-weighted and FAIR images. T*2-weighted images showed 1–4% relative signal intensity increases, while FAIR images demonstrated relative cerebral blood flow (CBF) increase up to 30–70%. The activated pixels depicted in FAIR images were about three times less than those seen in T*2-weighted images. With prolonged breath holding, it was observed that signal intensities in T*2-weighted and FAIR images were dependent on the breathing techniques used. Breath holding after expiration gave rise to immediate signal intensity increases in T*2-weighted and FAIR images, whereas breath holding performed after deep inspiration signals showed a biphasic change both in flow and T*2-weighted. T*2-weighted and FAIR signals showed a transient decrease before rising above the baseline level.