Myocardial Deformation Assessed by MR Feature Tracking in Groups of Patients With Ischemic Heart Disease.

BACKGROUND: Global myocardial strain assessments have been shown to provide useful measures of contractility in many diseases, but whether feature tracking (FT)-derived strain at rest can differentiate ischemic myocardium from infarcted and remote myocardium in patients with coronary artery disease (CAD) remains unclear. PURPOSE: To evaluate the performance of magnetic resonance imaging FT-derived strain in the detection of regional myocardial deformation in ischemic, infarcted, and apparent normal myocardium in CAD. STUDY TYPE: Retrospective POPULATION: A total of 109 patients with CAD. FIELD STRENGTH/SEQUENCES: Steady-state free-precession rest cine, T1-weighted saturation-recovery fast gradient echo stress/rest perfusion, and two-dimensional phase-sensitive inversion recovery breath-hold late gadolinium enhancement (LGE) tests were performed at 3.0 T. ASSESSMENT: Based on perfusion and LGE images, left ventricular (LV) myocardial segments of CAD patients were categorized into ischemic, infarcted, and negative groups. The FT longitudinal (LS) and circumferential strain (CS) of normal subjects and the three CAD groups were calculated. Z-scores of each segment of CAD patients were calculated. STATISTIC TESTS: χ2 testing, analysis of variance (ANOVA), and Kruskal-Wallis tests. Z-scores were used to compare the strain between CAD groups. RESULTS: There were significant differences in global LS (GLS) and CS (GCS) between healthy controls (GLS: -19.0% ± 1.4%, GCS, -20.9% ± 1.8%), ischemia (GLS: -17.4% ± 2.1%, GCS, -19.6% ± 1.9%), infarction (GLS: -16.4% ± 1.9%, GCS, -17.8% ± 1.9%), and negative patients (GLS: -17.7% ± 1.4%, GCS, -20.9% ± 2.4%) (all P < 0.05). There were significant differences in regional LS and CS between ischemic (LS, -16.1% ± 5.0%, CS, -18.7% ± 5.0%), infarcted (LS, -14.8% ± 5.2%, CS, -15.3% ± 4.8%), and negative segments (LS, -17.6% ± 5.2%, CS, -19.8% ± 4.8%) (all P < 0.05). The differences in the z-scores of regional LS and CS between the ischemic, infarcted, and negative segments were also significant (all P < 0.05). DATA CONCLUSION: FT-derived rest strain indices of the LV myocardium of CAD patients were higher compared to healthy controls and varied between ischemic, infarcted, and negative segments. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 5.

Dose-Lowering in Contrast-Enhanced MRI of the Central Nervous System: A Retrospective, Parallel-Group Comparison Using Gadobenate Dimeglumine.

BACKGROUND: Concerns over gadolinium (Gd) retention encourage the use of lower Gd doses. However, lower Gd doses may compromise imaging performance. Higher relaxivity gadobenate may be suited to reduced dose protocols. PURPOSE: To compare 0.05 mmol/kg and 0.1 mmol/kg gadobenate in patients undergoing enhanced MRI of the central nervous system (CNS). STUDY TYPE: Retrospective, multicenter. POPULATION: Three hundred and fifty-two patients receiving 0.05 (n = 181) or 0.1 (n = 171) mmol/kg gadobenate. FIELD STRENGTH/SEQUENCES: 1.5 T and 3.0 T/precontrast and postcontrast T1-weighted spin echo/fast spin echo (SE/FSE) and/or gradient echo/fast field echo (GRE/FFE); precontrast T2-weighted FSE and T2-FLAIR. ASSESSMENT: Images of patients with extra-axial lesions at 1.5 T or any CNS lesion at 3.0 T were reviewed by three blinded, independent neuroradiologists for qualitative (lesion border delineation, internal morphology visualization, contrast enhancement; scores from 1 = poor to 4 = excellent) and quantitative (lesion-to-brain ratio [LBR], contrast-to-noise ratio [CNR]; SI measurements at regions-of-interest on lesion and normal parenchyma) enhancement measures. Noninferiority of 0.05 mmol/kg gadobenate was determined for each qualitative endpoint if the lower limit of the 95% confidence interval (CI) for the difference in precontrast + postcontrast means was above a noninferiority margin of -0.4. STATISTICAL TESTS: Student's t-test for comparison of mean qualitative endpoint scores, Wilcoxon signed rank test for comparison of LBR and CNR values; Wilcoxon rank sum test for comparison of SI changes. Tests were significant for P < 0.05. RESULTS: The mean change from precontrast to precontrast + postcontrast was significant for all endpoints. Readers 1, 2, and 3 evaluated 304, 225, and 249 lesions for 0.05 mmol/kg gadobenate, and 382, 309, and 298 lesions for 0.1 mmol/kg gadobenate. The lower limit of the 95% CI was above -0.4 for all comparisons. Significantly, higher LBR and CNR was observed with the higher dose. DATA CONCLUSION: 0.05 mmol/kg gadobenate was noninferior to 0.1 mmol/kg gadobenate for lesion visualization. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 3.

Study protocol for a pilot clinical trial to understand neural mechanisms of response to a psychological treatment for pain and anxiety in pediatric functional abdominal pain disorders (FAPD).

BACKGROUND: Functional abdominal pain disorders (FAPD) are the most common chronic pain conditions of childhood and are made worse by co-occurring anxiety. Our research team found that the Aim to Decrease Pain and Anxiety Treatment (ADAPT), a six-session coping skills program using cognitive behavioral therapy strategies, was effective in improving pain-related symptoms and anxiety symptoms compared to standard care. In follow-up, this current randomized clinical trial (RCT) aims to test potential neural mechanisms underlying the effect of ADAPT. Specifically, this two-arm RCT will explore changes in amygdalar functional connectivity (primary outcome) following the ADAPT protocol during the water loading symptom provocation task (WL-SPT). Secondary (e.g., changes in regional cerebral blood flow via pulsed arterial spin labeling MRI) and exploratory (e.g., the association between the changes in functional connectivity and clinical symptoms) outcomes will also be investigated. METHODS: We will include patients ages 11 to 16 years presenting to outpatient pediatric gastroenterology care at a midwestern children's hospital with a diagnosis of FAPD plus evidence of clinical anxiety based on a validated screening tool (the Generalized Anxiety Disorder-7 [GAD-7] measure). Eligible participants will undergo baseline neuroimaging involving the WL-SPT, and assessment of self-reported pain, anxiety, and additional symptoms, prior to being randomized to a six-week remotely delivered ADAPT program plus standard medical care or standard medical care alone (waitlist). Thereafter, subjects will complete a post assessment neuroimaging visit similar in nature to their first visit. CONCLUSIONS: This small scale RCT aims to increase understanding of potential neural mechanisms of response to ADAPT. TRIAL REGISTRATION: ClinicalTrials.gov registration: NCT03518216.

Assessment of myocardial fibrosis and coronary arteries in hypertrophic cardiomyopathy using combined arterial and delayed enhanced CT: comparison with MR and coronary angiography.

OBJECTIVES: We sought to determine the feasibility and accuracy of dual-source computed tomography (DSCT) in assessing coronary artery disease and myocardial fibrosis of hypertrophic cardiomyopathy (HCM) compared with cardiac magnetic resonance (CMR) imaging and coronary angiography (CA). METHODS: Forty-seven consecutive patients with HCM were prospectively enrolled. DSCT images were acquired in the arterial and late phases following intravenous contrast medium. The CMR and CA were performed within 7 days. Independent blinded readers read each study. Patients were classified according to myocardial delayed enhanced (MDE) CMR, coronary artery stenosis by CA, and arterial and MDE-DSCT. The diagnostic accuracy of DSCT in detecting coronary stenosis and MDE was analysed. RESULTS: Wall thickness determined by DSCT was strongly correlated with MR results (r = 0.91). DSCT and CMR MDE showed substantial agreement for the detection of myocardial fibrosis on per-patient and per-segment levels. The CT classification of patients by arterial stenosis and delayed enhancement had excellent agreement with MR and CA methods. CONCLUSIONS: The comprehensive cardiac CT examination provides reliable coronary artery and myocardial assessments. MDE-DSCT is a robust alternative method to MDE-CMR in assessing myocardial fibrosis in HCM particularly in patients with pacemakers or other contraindications to CMR.

Does diffusion-weighted imaging predict short-term risk of stroke in emergency department patients with transient ischemic attack?

STUDY OBJECTIVE: The optimal diagnostic evaluation for establishing the risk of stroke among patients presenting to the emergency department (ED) with a transient ischemic attack has not been determined. The objective of this review is to assess the ability of diffusion-weighted magnetic resonance imaging (MRI) to predict the short-term risk of stroke. METHODS: MEDLINE, EMBASE, and the Cochrane Library were queried to identify studies examining the use of diffusion-weighted MRI in patients with classically defined transient ischemic attack. The primary outcome measure was the rate of stroke at 48 hours. Two reviewers determined study eligibility and extracted data. Quality was assessed according to published recommendations for the design and reporting of prognostic studies. RESULTS: One thousand six hundred ninety-six abstracts were identified and 35 articles underwent full-text review. Six cohort studies met the inclusion criteria but were limited by selection bias and differences in duration and completeness of follow-up. Results were not consistent across studies, with 5 reporting higher rates of stroke among diffusion-weighted MRI-positive patients, whereas 1 study reported higher rates in diffusion-weighted MRI-negative patients. Among the 4 studies (N=629 patients) reporting 48-hour outcomes, the risk of stroke ranged from 0% to 2.9% in patients with negative diffusion-weighted MRI findings compared with 0% to 9% among those with positive diffusion-weighted MRI results. CONCLUSION: Studies of variable quality, consistency, and precision suggest that diffusion-weighted MRI may identify patients at sufficiently low risk to warrant ED discharge and close outpatient follow-up.

Validation of black blood late gadolinium enhancement (LGE) for evaluation of myocardial infarction in patients with or without pathological Q-wave on electrocardiogram (ECG).

BACKGROUND: The pathological Q-wave (QW) is an important indicator of infarcted myocardial volume indicating a worse prognosis compared to non-Q-wave (NQW) infarctions. Traditional classification divides infarcts into transmural and non-transmural based on QW and NQW. This view has been challenged by the advent of late gadolinium enhancement (LGE) MR imaging. Conventional LGE (Conv-LGE) detection of subendocardial MI is limited by bright blood pool. Dark Blood LGE imaging (DB-LGE) nulls the blood pool improving the conspicuity and accuracy of detection of subendocardial infarcts. We hypothesize that improved detection of subendocardial enhancement with DB-LGE will result in improved correlation of electrocardiogram (ECG) and extent of infarction. METHODS: Sixty-four clinically confirmed infarction patients were enrolled in this prospective study. All the participants underwent cardiac MR imaging including conv-LGE and DB-LGE. Twelve-lead ECG were performed on the same day. The patients were divided into QW and NQW groups by one experienced cardiologist. MI quantitation was by MI% (the ratio of MI volume to whole myocardial volume) and transmural grading, compared using paired t-test and Wilcoxon-test, respectively. The image quality obtained by Conv-LGE and DB-LGE were evaluated according to the signal intensity ratio (SIR) and contrast-to-noise ratio (CNR). RESULTS: Fifty-six subjects were enrolled in the final analysis [23 (41%) QW and 33 (59%) NQW infarcts]. For the QW cohort, both sequences classified infarcts as transmural in 21/23 (91%) subjects and subendocardial in 2/23 (9%). For the NQW cohort, both sequences classified infarcts as transmural in 16/33 (48%) subjects and subendocardial in 17/33 (52%). Using BB-LGE there were significant differences in detecting subendocardial infarcts in QW and NQW cohorts (Z=-5.85, P<0.001). The MI% of QW group was greater than in NQW group (24.2±10.3 vs.15.9±9.8, P=0.003). Compared to Conv-LGE, BB-LGE provided higher CNR and SIR between infarcted myocardium and blood pool (6.3±2.6 vs. 2.1±1.3, P<0.001; 5.4±1.9 vs. 1.3±0.2, P<0.001). BB-LGE detected more subendocardial infarcted segments in the QW group and NQW group (Z=-4.24, P<0.001; Z=-5.57, P<0.001). The larger MI% was displayed in BB-LGE than in Conv-LGE in both QW group and NQW group (24.2±10.3 vs. 22.6±10.3, P<0.001; 15.9±9.8 vs.14.6±9.6, P=0.001). CONCLUSIONS: Compared to conventional LGE, DB-LGE can provide more accurate detection and characterization of infarction in terms of transmurality and subendocardial extent. This is important for evaluating QW and NQW MIs. Due to nulling the high signal of blood pool, DB-LGE can effectively improve the identification of subendocardial MI which may be missed on conventional LGE. Therefore, in both QW and NQW MIs, DB-LGE detects more subendocardial MIs and larger MI% is found. This may facilitate more accurate quantitative MR assessment of both QW and NQW MIs and further empower LGE volume as a predictive biomarker.

MDCT evaluation of central airway and vascular complications of lung transplantation.

OBJECTIVE: The purpose of this article is to illustrate the spectrum of central airway and vascular complications in lung transplantation using MDCT, with an emphasis on the usefulness of advanced postprocessing techniques. CONCLUSION: MDCT is an invaluable tool in the diagnosis, evaluation, and posttreatment assessment of central airway and vascular complications in lung transplant recipients. Advanced postprocessing techniques provide complementary information that is visually accessible and anatomically meaningful for the clinician.

A systematic review of neuroimaging for cerebral palsy.

The American Academy of Neurology now recommends that all cases of cerebral palsy of unknown origin undergo neuroimaging. Controversy surrounds this recommendation because of concerns about the adequacy of the supporting evidence. This article reviews the evidence provided by magnetic resonance imaging (MRI) and computed tomography (CT) imaging studies in cerebral palsy and discusses the potential benefits of imaging, techniques in current use, and future directions, with a focus on improving etiologic understanding. Most (83%) children with cerebral palsy have abnormal neuroradiological findings, with white matter damage the most common abnormality. Combined gray and white matter abnormalities are more common among children with hemiplegia; isolated white matter abnormalities are more common with bilateral spasticity or athetosis, and with ataxia; isolated gray matter damage is the least common finding. About 10% of cerebral palsy is attributable to brain malformations, and 17% of cerebral palsy cases have no abnormality detectable by conventional MR or CT imaging. Although neuroimaging studies have increased our understanding of the abnormalities in brain development in cerebral palsy, they are less informative than they might be because of 4 common problems: (1) inappropriate assignment of etiology to morphologic findings, (2) inconsistent descriptions of radiologic findings, (3) uncertain relationship of pathologic findings to brain insult timing estimates, and (4) study designs that are not based on generalizable samples. Neuroimaging is not necessarily required for diagnosis of cerebral palsy because the disorder is based on clinical findings. The principal contribution of imaging is to the understanding of etiology and pathogenesis, including ruling in or out conditions that may have implications for genetic counseling, such as malformations. In the future, as more sophisticated imaging procedures are applied to cerebral palsy, specific morphologic findings may be linked to etiologic events or exposures, thus leading to potential pathways for prevention.

3.0 T versus 1.5 T MR angiography of the head and neck.

This article presents the advantages and challenges of MR angiography of the intracranial and extracranial cerebral vasculature at 3.0 T with comparative assessment to 1.5 T approaches. The physical basis for the superiority of 3.0 T MR angiography is discussed in the context of evolving technological capabilities afforded by the synergistic advent of higher field scanners, improved coil design, and parallel imaging. This review emphasizes 3.0 T issues related to noncontrast three-dimensional time of flight MR angiography of the intracranial circulation, contrast enhanced three-dimensional time of flight MR angiography of the extracranial cerebral vasculature, and carotid plaque characterization.

3T MR imaging of the brain.

The advent of very high field clinical scanners that operate at 3T is taking structural and functional imaging to new levels and is reinvigorating clinical spectroscopy, fMR imaging, and noncontrast-enhanced methods of MRA. Most of the challenges that are related to 3T imaging have been addressed to facilitate routine clinical imaging. An awareness of the complexities that underlie the solutions to these challenges is important to the continued improvements to the 3T platform so that its maximal potential can be reached. The development of the multichannel-head coils and the improvement in the design of body coils, concurrently with the development of multichannel capabilities that enable parallel imaging, have benefited all field platforms. Perhaps the added value of parallel imaging has been greatest at 3T where the additional signal can be exploited. The definition of very high field is a moving target, and may be well on its way to 7.0 T, although in terms of the current clinical state of the art, 3T is our current reference.

High b-value diffusion imaging.

Perhaps one of the greatest benefits of the development of high b-value technology has been the insight provided into the physiologic basis of diffusion imaging. The multiexponential features of the diffusion process are revealed on scans obtained with high b-value. The subsequent isotropic diffusion images have the distinct advantage of more accurately reflecting the intrinsic ADC of the tissues examined. This feature has the potential to facilitate clinical diagnosis. The degree to which this is proved to be clinically relevant is dependent on future investigation, but initial results are promising. The clinical potential of high b-value imaging at higher field strength remains to be explored. The greater signal to noise afforded by the use of 3-T scanners will likely make higher b-value imaging more practical with less costly scan time penalties necessary at lower field strengths.

Thoracic radiculopathy.

Thoracic radiculopathy represents an uncommon spinal disorder that is frequently overlooked in the evaluation of spinal pain syndromes. Degenerative disc disease and diabetes mellitus may frequently cause radiculopathy at the thoracic level. Electromyography and magnetic resonance imaging are useful in the evaluation of radiculopathy and thoracic spinal pain syndromes. Percutaneous vertebroplasty is a procedure that may be used in the treatment of thoracic spinal pain syndromes. Surgical intervention for thoracic radiculopathy usually is reserved for patients with progressive myelopathy and neurologic compromise.

The Long-Term Clinical Outcomes Following Autogenous Bone Grafting for Large-Volume Defects of the Knee: 12- to 21-Year Follow-Up.

OBJECTIVE: We report the long-term clinical outcomes of patients who underwent autogenous bone grafting of large-volume osteochondral defects of the knee due to osteochondritis dessicans (OCD) and osteonecrosis (ON). This is the companion report to one previous published on the biological response. We hypothesized that these grafts would integrate with host bone and the articular surface would form fibrocartilage providing an enduring clinical benefit. DESIGN: Three groups (patients/knees) were studied: OCD without a fragment (n = 12/13), OCD with a partial fragment (n = 14/16), and ON (n = 25/26). Twenty-five of 52 patients were available for clinical follow-up between 12 and 21 years. Electronic medical records provided comparison clinical information. In addition, there were plain film radiographs, MRIs, plus repeat arthroscopy and biopsy on 14 patients. RESULTS: Autogenous bone grafts integrated with the host bone. MRI showed soft tissue covering all the grafts at long-term follow-up. Biopsy showed initial surface fibrocartilage that subsequently converted to fibrocartilage and hyaline cartilage at 20 years. OCD patients had better clinical outcomes than ON patients. No OCD patients were asymptomatic at anytime following surgery. Half of the ON patients came to total knee replacement within 10 years. CONCLUSIONS: Autogenous bone grafting provides an alternative biological matrix to fill large-volume defects in the knee as a singular solution integrating with host bone and providing an enduring articular cartilage surface. The procedure is best suited for those with OCD. The treatment for large-volume articular defects by this method remains salvage in nature and palliative in outcome.

Incorporating diffusion-weighted magnetic resonance imaging into an observation unit transient ischemic attack pathway: a prospective study.

BACKGROUND AND PURPOSE: National guidelines advocate for early, aggressive transient ischemic attack (TIA) evaluations and recommend diffusion-weighted magnetic resonance imaging (MRI) for brain imaging. The purpose of this study is to examine clinician compliance, the yield of MRI, and patient-centered clinical outcomes following implementation of an emergency department observation unit (EDOU) clinical pathway incorporating routine MRI into the acute evaluation of patients with TIA. METHODS: This is a prospective observational study of patients with TIA admitted from the ED. Patients with low-risk TIA were transferred to an EDOU for diagnostic testing including MRI; high-risk patients were directed to hospital admission. Clinical variables, diagnostic tests, and treatment were recorded for all patients. The primary clinical outcome was the rate of stroke or recurrent TIA, determined through telephone follow-up and medical record review at 7 and 30 days. RESULTS: A total of 116 patients with TIA were enrolled. In all, 92 (79.3%) patients were transferred to the EDOU, of whom 69 (59.5%) were discharged without hospitalization. Compliance with the EDOU pathway was 83 (91.2%) of 92. Magnetic resonance imaging demonstrated acute infarct in 16 (15.7%) of 102 patients. Stroke (n = 2) or TIA (n = 3) occurred in 5 patients with TIA (4.3%, 95% confidence interval: 1.6%-10.0%) within 30 days; no strokes occurred after discharge. CONCLUSIONS: Implementation of a TIA clinical pathway incorporating MRI effectively encouraged guideline-compliant diagnostic testing; however, patient-important outcomes appear similar to diagnostic protocols without routine MRI. Further study is needed to assess the benefits and costs associated with routinely incorporating MRI into TIA evaluation.

The Biological Response following Autogenous Bone Grafting for Large-Volume Defects of the Knee: Index Surgery through 12 to 21 Years' Follow-up.

OBJECTIVE: This report focuses on the biological events occurring at various intervals following autogenous bone grafting of large-volume defects of the knee joint's femoral condyle secondary to osteochondritis dissecans (OCD) or osteonecrosis (ON). It was hypothesized that the autogenous bone graft would integrate and the portion exposed to the articular surface would form fibrocartilage, which would endure for years. METHODS: Between September 29, 1987 and August 8, 1994, there were 51 patients treated with autogenous bone grafting for large-volume osteochondral defects. Twenty-five of the 51 patients were available for long-term follow-up up to 21 years. Patient follow-up was accomplished by clinical opportunity and intentional research. Videotapes were available on all index surgeries for review and comparison. All had preoperative and postoperative plain film radiographs. Long-term follow-up included MRI up to 21 years. Second-look arthroscopy and biopsy were obtained on 14 patients between 8 weeks and 20 years. RESULTS: Radiological assessment showed the autogenous bone grafts integrated with the host bone. The grafts retained the physical geometry of the original placement. MRI showed soft tissue covering the grafts in all cases at long-term follow-up. Interval biopsy showed the surface covered with fibrous tissue at 8 weeks and subsequently converted to fibrocartilage with hyaline cartilage at 20 years. CONCLUSION: Autogenous bone grafting provides a matrix for large osteochondral defects that integrates with the host bone and results in a surface repair of fibrocartilage and hyaline cartilage that can endure for up to 20 years.

Fibromatosis of the cervical region following laminectomy: a case report and literature review.

STUDY DESIGN: A case report and a discussion of recently published data. OBJECTIVE: To highlight the occurrence of postoperative fibromatosis arising in the cervical spine. SUMMARY OF BACKGROUND DATA: Fibromatosis is a benign, locally invasive fibroblastic proliferation that can cause compressive effects on adjacent structures. Although the precise etiology of fibromatosis remains unclear, numerous studies have investigated the role of pluripotent mesenchymal stem cells in ß-catenin-regulated tumorigenesis. At present, aggressive fibromatosis is managed with wide local excision. Postoperative radiation therapy is indicated for incomplete excision. METHODS: A 48-year-old woman presented with a 2-year history of enlarging paracervical fibromatosis after undergoing extensive cervicothoracic instrumentation for excision of an extradural schwannoma. The patient underwent wide local excision of the neck mass, with right trapezius myocutaneous flap reconstruction of the subsequent defect. RESULTS: Histologically, the lesion was shown to be fibromatosis. Six months postoperatively, the patient was doing well with no recurrence. CONCLUSION: Fibromatosis is an important diagnosis to consider when evaluating locally aggressive spinal lesions at sites of prior operative repair. Molecular and genetic studies pertaining to the role of mesenchymal stem cells and ß-catenin in the pathogenesis of aggressive fibromatosis tumors could lead to possible worthwhile treatment strategies in the future.

Quantitative analysis of the postcontractile blood-oxygenation-level-dependent (BOLD) effect in skeletal muscle.

Previous studies show that transient increases in both blood flow and magnetic resonance image signal intensity (SI) occur in human muscle after brief, single contractions, and that the SI increases are threefold larger in physically active compared with sedentary subjects. This study examined the relationship between these transient changes by measuring anterior tibial artery flow (Doppler ultrasound), anterior muscle SI (3T, one-shot echo-planar images, TR/TE = 1,000/35), and muscle blood volume and hemoglobin saturation [near-infrared spectroscopy (NIRS)] in the same subjects after 1-s-duration maximum isometric ankle dorsiflexion contractions. Arterial flow increased to a peak 5.9 ± 0.7-fold above rest (SE, n = 11, range 2.6-10.2) within 7 s and muscle SI increased to a peak 2.7 ± 0.6% (range 0.0-6.0%) above rest within 12 s after the contractions. The peak postcontractile SI change was significantly correlated with both peak postcontractile flow (r = 0.61, n = 11) and with subject activity level (r = 0.63, n = 10) estimated from 7-day accelerometer recordings. In a subset of 7 subjects in which NIRS data acquisition was successful, the peak magnitude of the postcontractile SI change agreed well with SI calculated from the NIRS blood volume and saturation changes (r = 0.80, slope = 1.02, intercept = 0.16), confirming the blood-oxygenation-level-dependent (BOLD) mechanism underlying the SI change. The magnitudes of postcontractile changes in blood saturation and SI were reproduced by a simple one-compartment muscle vascular model that incorporated the observed pattern of postcontractile flow, and which assumed muscle O(2) consumption peaks within 2 s after a brief contraction. The results show that muscle postcontractile BOLD SI changes depend critically on the balance between O(2) delivery and O(2) consumption, both of which can be altered by chronic physical activity.

Lumbar spine MRI in the elite-level female gymnast with low back pain.

OBJECTIVE: Previous studies have shown increased degenerative disk changes and spine injuries in the competitive female gymnast. However, it has also been shown that many of these findings are found in asymptomatic athletic people of the same age. Previous magnetic resonance imaging (MRI) studies evaluating the gymnastic spine have not made a distinction between symptomatic and asymptomatic athletes. Our hypothesis is that MRI will demonstrate the same types of abnormalities in both the symptomatic and asymptomatic gymnasts. DESIGN: Olympic-level female gymnasts received prospectively an MRI exam of the lumbar spine. Each of the gymnasts underwent a physical exam by a sports medicine physician just prior to the MRI for documentation of low back pain. Each MRI exam was evaluated for anterior apophyseal ring avulsion injury, compression deformity of the vertebral body, spondylolysis, spondylolisthesis, degenerative disease, focal disk protrusion/extrusion, muscle strain, epidural mass, and bone-marrow edema. PATIENTS: Nineteen Olympic-level female gymnasts (age 12-20 years) were evaluated prospectively in this study. All of these gymnasts were evaluated while attending a specific training camp. RESULTS: Anterior ring apophyseal injuries (9/19) and degenerative disk disease (12/19) were common. Spondylolysis (3/19) and spondylolisthesis (3/19) were found. Focal bone-marrow edema was found in both L3 pedicles in one gymnast. History and physical exam revealed four gymnasts with current low back pain at the time of imaging. There were findings confined to those athletes with current low back pain: spondylolisthesis, spondylolysis, bilateral pedicle bone-marrow edema, and muscle strain. CONCLUSIONS: Our initial hypothesis was not confirmed, in that there were findings that were confined to the symptomatic group of elite-level female gymnasts.

Elevated skeletal muscle phosphodiesters in adults using statin medications.

Elevated skeletal muscle phosphodiesters (PDE) have previously been reported with muscle-related disorders. Myalgia is a side effect of using statin cholesterol-lowering medications and, therefore, statin use may be associated with increased skeletal muscle PDE. The effect of cholesterol-lowering drugs on skeletal muscle phosphorus metabolites was determined with (31)P magnetic resonance spectroscopy. Resting (31)P metabolites of the anterior compartment muscles were measured in two groups (n = 20; age, 49 +/- 2 years); half were taking statins and the other half were not on these agents. Muscle PDE was 57% greater in the statin group than the control group. These data suggest that statin use increases muscle PDE. Our findings are particularly relevant due to the increasing use and higher dosing of statin medications. Further prospective studies should be performed to document a causal relationship between elevated PDE and statin use, in addition to quantifying correlates to muscle function.