A decade of DTI in traumatic brain injury: 10 years and 100 articles later

SUMMARY

The past decade has seen an increase in the number of articles reporting the use of DTI to detect brain abnormalities in patients with traumatic brain injury. DTI is well-suited to the interrogation of white matter microstructure, the most important location of pathology in TBI. Additionally, studies in animal models have demonstrated the correlation of DTI findings and TBI pathology. One hundred articles met the inclusion criteria for this quantitative literature review. Despite significant variability in sample characteristics, technical aspects of imaging, and analysis approaches, the consensus is that DTI effectively differentiates patients with TBI and controls, regardless of the severity and timeframe following injury. Furthermore, many have established a relationship between DTI measures and TBI outcomes. However, the heterogeneity of specific outcome measures used limits interpretation of the literature. Similarly, few longitudinal studies have been performed, limiting inferences regarding the long-term predictive utility of DTI. Larger longitudinal studies, using standardized imaging, analysis approaches, and outcome measures will help realize the promise of DTI as a prognostic tool in the care of patients with TBI.

Progressive encephalopathy in children with chronic renal insufficiency in infancy

A retrospective analysis of children with renal failure during the first year of life revealed that 20 of 23 patients developed profound neurologic abnormalities. The encephalopathy was characterized by developmental delay, microcephaly, hypotonia, seizures, dyskinesia, and EEG abnormalities. No patient had been dialyzed, and four had not received aluminum salts prior to the development of neurologic symptoms. Inadequate statural growth and poor nutrition were present in all patients. It is probable that infants with chronic renal insufficiency are more susceptible to the development of this syndrome than are older children or adults because of the significant growth and maturation of the brain that occurs during the first years of life.

The posterior aortic wall echocardiogram. Its relationship to left atrial volume change

The normal posterior aortic wall echocardiogram shows anterior motion during left ventricular systole and predominantly posterior motion in three phases during left ventricular diastole. In six patients undergoing simultaneous left atrial angiograms and posterior aortic wall echocardiograms, there was excellent correlation between the posterior aortic wall motion and the change in the left atrial angiographic area showing the value of the posterior aortic wall echocardiogram in describing the left atrial volume curve. Left atrial and left ventricular pressures were measured with manometer tip catheters and correlated with simultaneous posterior aortic wall and mitral valve echocardiograms in four patients with atrial septal defects. These echocardiographic, angiographic, and hemodynamic correlations, as well as other evidence reported in this paper suggest that a major portion of posterior aortic wall motion is related to left atrial events and describes the left atrial volume curve.

Ultrasonic backscatter system for automated on-line endocardial boundary detection: evaluation by ultrafast computed tomography

OBJECTIVES

The purpose of this study was to evaluate the accuracy of the recently developed echocardiographic on-line endocardial border detection system using ultrafast computed tomography, an independent and proved tomographic imaging modality.

BACKGROUND

The automated system for on-line endocardial border detection identifies the blood-tissue interface by acoustic quantification of the ultrasonic backscatter signal.

METHODS

Eighteen subjects were screened by conventional echocardiography and acoustic quantification. Ten of these, with high quality echocardiographic images, were also examined by ultrafast computed tomography. Comparable image planes at the midpapillary level were analyzed. Measurements of left ventricular cavity area were compared at end-diastole and end-systole and time course analyses of cavity area during the cardiac cycle were performed.

RESULTS

There was good correlation between values for left ventricular end-diastolic area (r = 0.99), end-systolic area (r = 0.93) and fractional area change (r = 0.91) using the two methods. The on-line backscatter system underestimated end-diastolic area (p < 0.001), but the negative bias was small (-1.6 cm2) and the 95% confidence intervals were narrow (-3.6 cm2 to +0.4 cm2). In contrast, the backscatter system overestimated end-systolic area (p < 0.02); the positive bias for this variable was also small (+2.6 cm2) but the confidence intervals were relatively wide (+7.9 to -2.8 cm2). The negative bias of backscatter values for cavity area was fairly constant during diastole and early systole (range -5% to -10%), but during the second half of systole, backscatter values increased progressively relative to computed tomographic values. Real time values for fractional area change measured by the backscatter system were 13% smaller than those determined by ultrafast computed tomography (p < 0.001), with wide confidence intervals (+3% to -30%). Absolute peak rates of area change during systole and diastole were lower by 39% (p < 0.001) and 41% (p < 0.01), respectively, using the on-line ultrasonic backscatter system. Time course analyses revealed the errors to be consistent with cardiac cycle-dependent alterations in gain sensitivity of the ultrasonic backscatter system.

CONCLUSIONS

The ultrasonic backscatter system is associated with cyclic cavity area measurement errors that need to be addressed if its early promise for on-line assessment of ventricular function is to be fulfilled. Incorporation of an electrocardiographically triggered time-varying gain control may improve accuracy for on-line analysis of ventricular performance.

Hippocampal correlates of pain in healthy elderly adults: a pilot study

BACKGROUND

Few neuroimaging investigations of pain in elderly adults have focused on the hippocampus, a brain structure involved in nociceptive processing that is also subject to involution associated with dementing disorders. The goal of this pilot study was to examine MRI- and magnetic resonance spectroscopy (MRS)-derived hippocampal correlates of pain in older adults.

METHODS

A subset of 20 nondemented older adults was drawn from the Einstein Aging Study, a community-based sample from the Bronx, NY. Pain was measured on 3 time scales: 1) acute pain right now (pain severity); 2) pain over the past 4 weeks (Short Form-36 Bodily Pain); 3) chronic pain over the past 3 months (Total Pain Index). Hippocampal data included volume data normalized to midsagittal area and N-acetylaspartate to creatine ratios (NAA/Cr).

RESULTS

Smaller hippocampal volume was associated with higher ratings on the Short Form-36 Bodily Pain (r(s) = 0.52, p = 0.02) and a nonsignificant trend was noted for higher ratings of acute pain severity (r(s) = -0.44, p = 0.06). Lower levels of hippocampal NAA/Cr were associated with higher acute pain severity (r(s) = -0.45, p = 0.05). Individuals with chronic pain had a nonsignificant trend for smaller hippocampal volumes (t = 2.00, p = 0.06) and lower levels of hippocampal NAA/Cr (t = 1.71, p = 0.10).

CONCLUSIONS

Older adults who report more severe acute or chronic pain have smaller hippocampal volumes and lower levels of hippocampal N-acetylaspartate/creatine, a marker of neuronal integrity. Future studies should consider the role of the hippocampus and other brain structures in the development and experience of pain in healthy elderly and individuals with Alzheimer disease.

Muscle phosphofructokinase deficiency: two cases with unusual polysaccharide accumulation and immunologically active enzyme protein

Two patients with phosphofructokinase (PFK) deficiency had exercise intolerance and increased serum activity of creatine kinase; one presented with hemolytic anemia, hyperuricemia, and gouty arthritis. The glycogen concentration in the muscle of these patients was about twice normal. PFK activity was virtually absent in muscle, but antibodies against the M subunits of the normal human PFK showed cross-reacting material in muscle from both patients. The PFK level in red blood cells, studied in one case, was lower than normal in the patient and both parents. Morphologically, there was extensive deposition of normal glycogen underneath the sarcolemma and in the intermyofibrillar space. In addition, 2% to 3% of the myofibers contained hyaline, PAS-positive, diastase-resistant inclusions that had a filamentous fine structure; histochemical reactions suggested an insoluble form of glycogen. Similar inclusions have not been described previously in PFK deficiency. Accumulation of an abnormal polysaccharide in muscle may be due to a second undiscovered enzymatic defect or may be a metabolic consequence of PFK deficiency.

A specific inhibitor of complement (C5)-derived chemotactic activity in serum from patients with systemic lupus erythematosus

In the course of examining polymorphonuclear leukocyte (PMN) chemotaxis in patients with systemic lupus erythematosus (SLE), we have found a previously undescribed serum inhibitor of complement (C5)-derived chemotactic activity. Serum from a 25-yr-old Black female with untreated SLE, when activated with zymosan, failed completely to attract either her own or normal PMN. Incubation of normal PMN with the patient's serum did not affect their subsequent random motility or chemotactic response toward normal zymosan-treated serum (ZTS). The patient's serum, however, did inhibit the chemotactic activity of normal ZTS and of column-purified C5-derived peptide(s), but had no effect on the chemotactic activity of either the synthetic peptide, N-formylmethionyl leucyl-phenylalanine or a filtrate prepared from a culture of Escherichia coli (bacterial chemotactic factor). The inhibitory activity in the patient's serum resisted heating at 56 degrees C for 30 min and could be separated from C5-derived chemotactic activity in the patient's ZTS (or normal ZTS that had been incubated with the patient's serum) by chromatography on Sephadex G-75. Despite its effect on C5-derived chemotactic activity, the patient's serum did not influence two other C5-derived biologic activities: PMN lysosomal enzyme-releasing activity and PMN-aggregating activity. Chromatography of the patient's serum (65% ammonium sulfate pellet) on Sephadex G-200 yielded three distinct peaks of inhibitory activity. Two were heat labile and exhibited other properties of the previously described chemotactic factor inactivators of normal human serum. The third and most active peak, however, resisted heating at 56 degrees C for 30 min, eluted with an apparent mol wt of 50,000-60,000, and acted specifically on C5-derived chemotactic activity. This uniquely specific, heat-stable inhibitor of C5-derived chemotactic activity has been found thus far in serum from 4 of 11 patients with active SLE and may account, in part, for altered host defenses against infections caused by pyogenic microorganisms.

A randomized controlled trial of laser treatment among hirsute women with polycystic ovary syndrome

BACKGROUND

Facial hirsutism is one of the characteristic features of polycystic ovary syndrome (PCOS), and this can lead to high levels of depression and anxiety.

OBJECTIVES

To evaluate the impact of laser treatment on the severity of facial hirsutism and on psychological morbidity in women with PCOS.

METHODS

A randomized controlled trial of five high-fluence treatments (intervention) vs. five low-fluence treatments (control) was performed over 6 months in a National Health Service teaching hospital. Subjects were 88 women with facial hirsutism due to PCOS recruited from hospital outpatient clinics and a patient support group in 2001-2002. The main outcomes were self-reported severity of facial hair (measured on a scale of 1-10), depression, anxiety (measured on the Hospital Anxiety and Depression Scale) and quality of life (measured on the WHOQOL-BREF).

RESULTS

Self-reported severity of facial hair in the intervention group (n = 51) fell from 7.3 to 3.6 over the 6-month study period; for the control group (n = 37) the corresponding scores were 7.1 and 6.1. The change was significantly greater in the intervention group [ancova F((1,83)) = 24.5, P < 0.05]. Self-reported time spent on hair removal declined from 112 to 21 min per week in the intervention group and from 92 to 56 min in the control group [F((1,80)) = 10.2, P </= 0.05]. Mean depression scores fell from 6.7 to 3.6 in the intervention group, compared with 6.1 to 5.4 in the control group [F((1,83)) = 14.7, P < 0.05]. A similar change was seen for mean anxiety scores: intervention 11.1 to 8.2, control 9.6 to 9.3 [F((1,84)) = 17.8, P < 0.05]. Psychological quality of life also improved more in the intervention group, from 49.6 to 61.2 vs. 50.1 to 51.5 in the control group [F((1,84)) = 10.9, P < 0.05].

CONCLUSIONS

Laser treatment appeared to reduce the severity of facial hair and time spent on hair removal as well as alleviating depression and anxiety in women with PCOS. These findings suggest that ways of making this method of hair removal more widely available to women with facial hirsutism should be considered.

Utility of diffusion tensor imaging in evaluation of the peritumoral region in patients with primary and metastatic brain tumors

In the brain, diffusion tensor imaging is a useful tool for defining white matter anatomy, planning a surgical approach to space-occupying lesions, and characterizing tumors, including distinguishing primary tumors from metastases. Recent studies have attempted, with varying success, to use DTI to define the extent of tumor microinfiltration beyond the apparent borders on T2-weighted imaging. In the present review, we discuss the current state of research on the utility of DTI for evaluating the peritumoral region of brain tumors.

Operation for chronic constrictive pericarditis: Do the surgical approach and degree of pericardial resection influence the outcome significantly?

Our experience with 27 patients undergoing pericardiectomy at New York University Medical Center over the past 13 years has evolved a radical pericardiectomy operation suggesting that two traditional concepts are erroneous: (1) pericardiectomy limited to the anterior and lateral surfaces of the ventricles is an adequate operation and (2) delayed recovery is due to myocardial "atrophy" and not to inadequate operation. Radical pericardiectomy entails removal of virtually the entire parietal pericardium from all cardiac surfaces including that of both ventricles, the right atrium, and the venae cavae. Performed in 22 patients by dissecting a cleavage plane between the thickened parietal pericardium and underlying epicardium, all procedures were done through a sternotomy. Intraoperative monitoring of arterial pressure, cardiac output, and wedge pressure is essential because of displacement of the left ventricle. The left ventricle can be completely mobilized so that at the end of the operation the entire heart can be lifted upward and the course of the coronary sinus fully visualized. Intraoperative pressure measurements demonstrate that this radical resection immediately corrects hemodynamic abnormalities (elevated right atrial and ventricular end-diastolic pressures), as demonstrated in 10 patients. Most patients undergo massive diuresis (7 to 16 kg) within two weeks, with an uneventful recovery. These findings contrast markedly with early experiences using a conventional limited pericardiectomy.

Sequelae of thrombotic or hemorrhagic complications following L-asparaginase therapy for childhood lymphoblastic leukemia

Thirty-four cases of childhood lymphoblastic leukemia that were complicated by CNS and peripheral thrombosis or hemorrhage associated with L-asparaginase (L-asp) therapy were reviewed to determine the effect of the events on the subsequent clinical status. There was no predilection for any site in the CNS cases; all but one of the peripheral events occurred in the lower extremities. The median time for 28 CNS and eight peripheral events from the beginning of L-asp therapy was 17 and 16 days, respectively. One patient died as a result of the CNS event. Twenty-six patients were surviving with a median follow-up of 27 months at the close of the study. Of the patients with peripheral thromboses, only the patient with a dorsal pedal artery occlusion had a significant problem (autoamputation of a toe). Although eight patients received L-asp subsequently without recurrence of the complication, two had transient neurological deterioration associated with the repeat administration of L-asp. Twenty-two patients received CNS prophylaxis consisting of intrathecal methotrexate, CNS radiation, or both, following the CNS event without deterioration. In general, clinical status was not compromised after thrombotic or hemorrhagic events. Although most patients had gross recovery of their neurological impairment, detailed neurological and neuropsychological testing is needed to elucidate possible defects.

Articular cartilage preservation and storage. I. Application of tissue culture techniques to the storage of viable articular cartilage

Articular cartilage slice explants were stored under various conditions, including freezing-thawing at various rates by using dimethyl sulfoxide (DMSO) as a cryoprotective agent, incubating in standard tissue culture medium (MEM Eagle:NCTC 135:15% fetal calf serum) in 5% CO2 and air at 4 degrees, 21 degrees, and 37 degrees C, and incubating in standard tissue culture medium containing 200 micrograms/ml alpha-tocopherol (vitamin E) at 37 degrees C after first ascertaining a dose-response curve of vitamin E. Results indicated that articular cartilage slice explants did not survive freezing or storage at 4 degrees and 21 degrees C as measured by 35S uptake. When stored at 37 degrees C in standard tissue culture in 5% CO2 and air, the slice explants remained viable for up to 60 days. The addition of alpha-tocopherol to the medium resulted in significantly less release of previously incorporated 35Sin stored cartilage slices and significantly less reduction of the amount of hexosamine present in the stored explants. alpha-Tocopherol in the medium also preserved safranin O staining. Thus, the application of tissue culture techniques to the storage of articular cartilage made it possible to preserve cartilage slice explants in a viable, biochemically "normal" state.

Validation and calibration of HeadCount, a self-report measure for quantifying heading exposure in soccer players

The long-term effects of repetitive head impacts due to heading are an area of increasing concern, and exposure must be accurately measured; however, the validity of self-report of cumulative soccer heading is not known. In order to validate HeadCount, a 2-week recall questionnaire, the number of player-reported headers was compared to the number of headers observed by trained raters for a men's and a women's collegiate soccer teams during an entire season of competitive play using Spearman's correlations and intraclass correlation coefficients (ICCs), and calibrated using a generalized estimating equation. The average Spearman's rho was 0.85 for men and 0.79 for women. The average ICC was 0.75 in men and 0.38 in women. The calibration analysis demonstrated that men tend to report heading accurately while women tend to overestimate. HeadCount is a valid instrument for tracking heading behaviour, but may have to be calibrated in women.

Bidirectional Changes in Anisotropy Are Associated with Outcomes in Mild Traumatic Brain Injury

BACKGROUND AND PURPOSE

Mild traumatic brain injury results in a heterogeneous constellation of deficits and symptoms that persist in a subset of patients. This prospective longitudinal study identifies early diffusion tensor imaging biomarkers of mild traumatic brain injury that significantly relate to outcomes at 1 year following injury.

MATERIALS AND METHODS

DTI was performed on 39 subjects with mild traumatic brain injury within 16 days of injury and 40 controls; 26 subjects with mild traumatic brain injury returned for follow-up at 1 year. We identified subject-specific regions of abnormally high and low fractional anisotropy and calculated mean fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity across all white matter voxels brain-wide and each of several white matter regions. Assessment of cognitive performance and symptom burden was performed at 1 year.

RESULTS

Significant associations of brain-wide DTI measures and outcomes included the following: mean radial diffusivity and mean diffusivity with memory; and mean fractional anisotropy, radial diffusivity, and mean diffusivity with health-related quality of life. Significant differences in outcomes were found between subjects with and without abnormally high fractional anisotropy for the following white matter regions and outcome measures: left frontal lobe and left temporal lobe with attention at 1 year, left and right cerebelli with somatic postconcussion symptoms at 1 year, and right thalamus with emotional postconcussion symptoms at 1 year.

CONCLUSIONS

Individualized assessment of DTI abnormalities significantly relates to long-term outcomes in mild traumatic brain injury. Abnormally high fractional anisotropy is significantly associated with better outcomes and might represent an imaging correlate of postinjury compensatory processes.

Technical aspects and clinical applications of CT/X, a dynamic CT scanner

CT/X is an X-ray computed tomographic scanner system designed for research in the clinical applications of rapid sequence scanning. The minimum scan time is 1.5 sec, and up to 18 images of the same cross section can be derived from scans taken over a 30 sec time interval. With this high image rate, the transit of a bolus of iodinated contrast medium can be followed through any cross section of the body. Rapid sequence scanning through a series of contiguous levels can also be performed, and 12 levels can be scanned in less than 50 sec. The short aggregate scan period minimizes the likelihood of interslice patient motion resulting in high quality multiplanar images. To fully exploit this capability, an imaging facility capable of reformatting axial transverse display data into a plane of arbitrary orientation has been incorporated into the system. A computer-electrocardiographic interface is also provided for use in retrospective cardiac gating. The capabilities of the scanner are illustrated with selective clinical studies.

Venous invasion in renal vein leiomyosarcoma: case report and review of the literature

Tumors arising from veins are rare, usually present with nonspecific clinical and imaging findings and almost universally show histology of leiomyosarcoma. This twentieth reported case of primary renal vein leiomyosarcoma demonstrates invasion of the renal vein with endoluminal propagation of tumor into the infrahepatic inferior vena cava (IVC), an unreported manifestation. The combination of CT, ultrasound, and angiographic studies allowed differentiation from renal cell carcinoma by suggesting a tumor arising from the renal vein.

The importance of children's illness beliefs: the Children's Illness Perception Questionnaire (CIPQ) as a reliable assessment tool for eczema and asthma

A lack of information about disease in children can lead to erroneous views such as children believing that hospital admittance or the presence of a disease is a punishment for a perceived wrong. There has thus far been no standard tool available to measure children's illness conceptualizations from a Leventhalian framework. Three groups of children with eczema, asthma and eczema and asthma between the ages of 7 and 12 years of age were recruited. Children were given the Children's Illness Perception Questionnaire (CIPQ), a 26-item instrument adapted from the Illness Perception Questionnaire for adults. A Kuder - Richardson 20 test of reliability for dichotomous data was performed allowing an estimate of the internal consistency of the measurement scales. It can be seen that, for all three illness groups, internal consistency is acceptable for the timeline and consequences scale. The cure/control scale, however, was not internally consistent for any illness group. As health professionals, we need to develop the means to further understand how paediatric illness beliefs relate to specific disease types, age and psychosocial factors and the utility of this instrument is discussed within this context.

Challenges to meet: food and nutrition security in the new millennium

Before about 1750 there was no substantial secular fall in protein-energy malnutrition (PEM) over large areas, nor reason to expect it. We have since learned that sufficient economic advance (poverty reduction) plus scientific advance (in medicine and food production) are achievable to eliminate mass PEM. The two advances are linked via increased demand for labour, and hence wages and employment, for those formerly too poor to afford adequate food. The extra employment income arises first from smallholder and employee food production, and later, as labour is released, from a wide range of specialised, increasingly non-farm, production, with employment income traded for food. This process eliminated mass hunger in Europe in 1750-1960. Only by 1975 had PEM in the developing world retreated to (very high) 1936-8 levels, but it fell sharply in Asia and Latin America in 1975-1990, due to unprecedented growth in staples yields, smallholder and farm employment income, and hence the poor's purchasing power over food. However, since 1990, poverty reduction has slowed (before reaching most of Africa), alongside much slower-staples yield growth, increasing water shortages, and big shifts of grain and land from man to farm animals. These trends prefigure declining progress against PEM in coming decades, unless there is renewed, employment-intensive food-staples-yield growth. That process requires reorienting crop biotechnology and water science towards the needs of small tropical farmers and their staple food crops, and shifting land towards them. Mass PEM is indeed largely due to inadequate 'food entitlements' by the hungry, but will not be remedied without growth in their employment, based on further advances in food-staples yields per unit land and water. Recent evidence suggests that early PEM may increase lifelong risks of infection and/or degenerative disease. This factor would increase the 'squeeze' on health resources in low-income countries, between the diseases of poverty and those of old age. That situation increases the need to readdress PEM by renewed progress in food production and land distribution.

RF excitation profiles with FAIR: impact of truncation of the arterial input function on quantitative perfusion

This study investigates the impact of imaging coil length and consequent truncation of the arterial input function on the perfusion signal contrast obtained in the flow-sensitive alternating inversion recovery (FAIR) perfusion imaging measurement. We examined the difference in perfusion contrast achieved with head, head and neck, and body imaging coils based on the hypothesis that the standard head coil provides a truncated input function compared with that provided by the body coil and that this effect will be accentuated at long inversion times. The TI-dependent cerebral response of the FAIR sequence was examined at 1.5 T by varying the TI from 200 to 3500 msec with both the head and whole body coils (n = 5) as well as using a head and neck coil (n = 3). Difference signal intensity DeltaM and quantitative cerebral blood flow (CBF) were plotted against TI for each coil configuration. Despite a lower signal-to-noise ratio, relative CBF was significantly greater when measured with the body or head and neck coil compared with the standard head coil for longer inversion times (two-way ANOVA, P < or = 0.002). This effect is attributed to truncation of the arterial input function of labeled water by the standard head coil and the resultant inflow of unlabeled spins to the image slice during control image acquisition, resulting in overestimation of CBF. The results support the conclusion that the arterial input function depends on the anatomic extent of the inversion pulse in FAIR, particularly at longer mixing times (TI > 1200 msec at 1.5 T). Use of a head and neck coil ensures adequate inversion while preserving SNR that is lost in the body coil.

Performing MRI on patients with MRI-conditional and non-conditional cardiac implantable electronic devices: an update for radiologists

Pacemakers and implantable cardioverter defibrillators are commonly encountered in clinical practice, and entails special consideration when magnetic resonance imaging (MRI) is required. It is estimated that 50-75% of patients with cardiac implantable electronic devices (CIED) will have an indication for MRI during their lifetime. Radiologists may want to recommend MRI or may be consulted about the need to perform MRI in a patient with a CIED, at which point they may need to approve or at least provide guidance as to whether MRI may be performed safely. Even in situations where final clearance will not be provided by the radiologist, he or she can provide valuable information by reviewing radiographs and determining (a) whether a device is MRI-conditional and MRI may ultimately be permitted, (b) is not MRI-conditional and MRI using the standard workflow will therefore not be approved, or (c) when additional information will clearly be required. CIED identification and verification of leads can be accomplished through review of the medical record and/or evaluation of a chest radiograph. In patients with MRI-conditional CIEDs (as well as with legacy CIEDs in those institutions that perform MRI of these patients), specific imaging protocols must be adhered to in order to prevent death or injury to the patient or damage to the device. In this update, we provide details regarding the above topics and provide an algorithm for integrating this information into a clinical workflow to efficiently triage patients with CIEDs who are being considered for MRI.