Transforming a pre-existing MRI environment into an interventional cardiac MRI suite.

AIMS: To illustrate the practical and technical challenges along with the safety aspects when performing MRI-guided electrophysiological procedures in a pre-existing diagnostic magnetic resonance imaging (MRI) environment. METHODS AND RESULTS: A dedicated, well-trained multidisciplinary interventional cardiac MRI team (iCMR team), consisting of electrophysiologists, imaging cardiologists, radiologists, anaesthesiologists, MRI physicists, electrophysiological (EP) and MRI technicians, biomedical engineers, and medical instrumentation technologists is a prerequisite for a safe and feasible implementation of CMR-guided electrophysiological procedures (iCMR) in a pre-existing MRI environment. A formal dry run "mock-up" to address the entire spectrum of technical, logistic, and safety issues was performed before obtaining final approval of the Board of Directors. With this process we showed feasibility of our workflow, safety protocol, and bailout procedures during iCMR outside the conventional EP lab. The practical aspects of performing iCMR procedures in a pre-existing MRI environment were addressed and solidified. Finally, the influence on neighbouring MRI scanners was evaluated, showing no interference. CONCLUSION: Transforming a pre-existing diagnostic MRI environment into an iCMR suite is feasible and safe. However, performing iCMR procedures outside the conventional fluoroscopic lab, poses challenges with technical, practical, and safety aspects that need to be addressed by a dedicated multi-disciplinary iCMR team.

Evaluation of a real-time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia substrate assessment.

AIMS: Potential advantages of real-time magnetic resonance imaging (MRI)-guided electrophysiology (MR-EP) include contemporaneous three-dimensional substrate assessment at the time of intervention, improved procedural guidance, and ablation lesion assessment. We evaluated a novel real-time MR-EP system to perform endocardial voltage mapping and assessment of delayed conduction in a porcine ischaemia-reperfusion model. METHODS AND RESULTS: Sites of low voltage and slow conduction identified using the system were registered and compared to regions of late gadolinium enhancement (LGE) on MRI. The Sorensen-Dice similarity coefficient (DSC) between LGE scar maps and voltage maps was computed on a nodal basis. A total of 445 electrograms were recorded in sinus rhythm (range: 30-186) using the MR-EP system including 138 electrograms from LGE regions. Pacing captured at 103 sites; 47 (45.6%) sites had a stimulus-to-QRS (S-QRS) delay of ≥40 ms. Using conventional (0.5-1.5 mV) bipolar voltage thresholds, the sensitivity and specificity of voltage mapping using the MR-EP system to identify MR-derived LGE was 57% and 96%, respectively. Voltage mapping had a better predictive ability in detecting LGE compared to S-QRS measurements using this system (area under curve: 0.907 vs. 0.840). Using an electrical threshold of 1.5 mV to define abnormal myocardium, the total DSC, scar DSC, and normal myocardium DSC between voltage maps and LGE scar maps was 79.0 ± 6.0%, 35.0 ± 10.1%, and 90.4 ± 8.6%, respectively. CONCLUSION: Low-voltage zones and regions of delayed conduction determined using a real-time MR-EP system are moderately associated with LGE areas identified on MRI.

A numerical investigation on the effect of RF coil feed variability on global and local electromagnetic field exposure in human body models at 64 MHz.

PURPOSE: This study aims to investigate how the positions of the feeding sources of the transmit radiofrequency (RF) coil, field orientation direction with respect to the patient, and patient dimensions affect the global and local electromagnetic exposure in human body models. METHODS: Three RF coil models were implemented, namely a specific two-source (S2) feed and two multisource feed configurations: generic 32-source (G32) and hybrid 16-source (H16). Thirty-two feeding conditions were studied for the S2, whereas two were studied for the G32 and H16. The study was performed using five human body models. Additionally, for two of the body models, the case of a partially implanted lead was evaluated. RESULTS: The results showed an overall variation due to coil feeding conditions of the whole-body specific absorption rate (SAR) of less than 20%, but deviations up to 98% of the magnitude of the electric field tangential to a possible lead path. For the analysis with the partially implanted lead, a variation of local SAR at the tip of the lead of up to 60% was observed with respect to feed position and field orientation direction. CONCLUSION: The results of this study suggest that specific information about feed position and field orientation direction must be considered for an accurate evaluation of patient exposure. Magn Reson Med 79:1135-1144, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Epicardial electroanatomical mapping, radiofrequency ablation, and lesion imaging in the porcine left ventricle under real-time magnetic resonance imaging guidance-an in vivo feasibility study.

Aims: Magnetic resonance imaging (MRI) is the gold standard for defining myocardial substrate in 3D and can be used to guide ventricular tachycardia ablation. We describe the feasibility of using a prototype magnetic resonance-guided electrophysiology (MR-EP) system in a pre-clinical model to perform real-time MRI-guided epicardial mapping, ablation, and lesion imaging with active catheter tracking. Methods and results: Experiments were performed in vivo in pigs (n = 6) using an MR-EP guidance system research prototype (Siemens Healthcare) with an irrigated ablation catheter (Vision-MR, Imricor) and a dedicated electrophysiology recording system (Advantage-MR, Imricor). Following epicardial access, local activation and voltage maps were acquired, and targeted radiofrequency (RF) ablation lesions were delivered. Ablation lesions were visualized in real time during RF delivery using MR-thermometry and dosimetry. Hyper-acute and acute assessment of ablation lesions was also performed using native T1 mapping and late-gadolinium enhancement (LGE), respectively. High-quality epicardial bipolar electrograms were recorded with a signal-to-noise ratio of greater than 10:1 for a signal of 1.5 mV. During epicardial ablation, localized temperature elevation could be visualized with a maximum temperature rise of 35 °C within 2 mm of the catheter tip relative to remote myocardium. Decreased native T1 times were observed (882 ± 107 ms) in the lesion core 3-5 min after lesion delivery and relative location of lesions matched well to LGE. There was a good correlation between ablation lesion site on the iCMR platform and autopsy. Conclusion: The MR-EP system was able to successfully acquire epicardial voltage and activation maps in swine, deliver, and visualize ablation lesions, demonstrating feasibility for intraprocedural guidance and real-time assessment of ablation injury.

Evaluating the older adult experience of a web-based, tablet-delivered heart failure self-care program using gerontechnology principles.

The goals of gerontechnology are to develop technology that facilitates goal attainment and improves satisfaction with life for older adults. Few mHealth technology systems have been evaluated using these criteria. The purpose of this paper was to present the qualitative analysis of participant post-intervention interviews from the tablet-delivered Penn State Heart Assistant intervention. Semi-structured interviews (n = 12) were conducted after the completion of a 30 day study protocol. Interviews were transcribed verbatim by a professional transcriptionist, then analyzed using an iterative process of coding, categorization, and thematic development using DeDoose software and a gerontechnology interpretive lens. Two themes with six subthemes arose: Benefits - information sharing with others, usability and learnability, use of help resources; Suggestions - continuing use after the study, technical problems, participant suggested improvements. Interviews suggested improved goal attainment and satisfaction with life for the older adults with use of the tablet.

Evaluation of the RF heating of a generic deep brain stimulator exposed in 1.5 T magnetic resonance scanners.

The radio frequency (RF) electromagnetic field of magnetic resonance (MR) scanners can result in significant tissue heating due to the RF coupling with the conducting parts of medical implants. The objective of this article is to evaluate the advantages and shortcomings of a new four-tier approach based on a combined numerical and experimental procedure, designed to demonstrate safety of implants during MR scans. To the authors' best knowledge, this is the first study analyzing this technique. The evaluation is performed for 1.5 T MR scanners using a generic model of a deep brain stimulator (DBS) with a straight lead and a helical lead. The results show that the approach is technically feasible and provides sound and conservative information about the potential heating of implants. We demonstrate that (1) applying optimized tools results in reasonable uncertainties for the overall evaluation; (2) each tier reduces the overestimation by several dB at the cost of more demanding evaluation steps; (3) the implant with the straight lead would cause local temperature increases larger than 18 °C at the RF exposure limit for the normal operating mode; (4) Tier 3 is not sufficient for the helical implant; and (5) Tier 4 might be too demanding to be performed for complex implants. We conclude with a suggestion for a procedure that follows the same concept but is between Tier 3 and 4. In addition, the evaluation of Tier 3 has shown consistency with current scan practice, namely, the resulting heat at the lead tip is less than 3.5 °C for the straight lead and 0.7 °C for the helix lead for scans at the current applied MR scan restrictions for deep brain stimulation at a head average SAR of 0.1 W/kg.

Effect of adolescent pregnancy on final adult height in non-Hispanic white women.

PURPOSE: The objective of this study is to examine the effect of pregnancy on final adult height in women whose first live birth occurred in adolescence (

Active Tracking-based cardiac triggering for MR-thermometry during radiofrequency ablation therapy in the left ventricle.

Cardiac MR thermometry shows promise for real-time guidance of radiofrequency ablation of cardiac arrhythmias. This technique uses ECG triggering, which can be unreliable in this situation. A prospective cardiac triggering method was developed for MR thermometry using the active tracking (AT) signal measured from catheter microcoils. In the proposed AT-based cardiac triggering (AT-trig) sequence, AT modules were repeatedly acquired to measure the catheter motion until a cardiac trigger was identified to start cardiac MR thermometry using single-shot echo-planar imaging. The AT signal was bandpass filtered to extract the motion induced by the beating heart, and cardiac triggers were defined as the extremum (peak or valley) of the filtered AT signal. AT-trig was evaluated in a beating heart phantom and in vivo in the left ventricle of a swine during temperature stability experiments (6 locations) and during one ablation. Stability was defined as the standard deviation over time. In the phantom, AT-trig enabled triggering of MR thermometry and resulted in higher temperature stability than an untriggered sequence. In all in vivo experiments, AT-trig intervals matched ECG-derived RR intervals. Mis-triggers were observed in 1/12 AT-trig stability experiments. Comparable stability of MR thermometry was achieved using peak AT-trig (1.0 ± 0.4°C), valley AT-trig (1.1 ± 0.5°C), and ECG triggering (0.9 ± 0.4°C). These experiments show that continuously acquired AT signal for prospective cardiac triggering is feasible. MR thermometry with AT-trig leads to comparable temperature stability as with conventional ECG triggering. AT-trig could serve as an alternative cardiac triggering strategy in situations where ECG triggering is not effective.

Unbiased discovery of autoantibodies associated with severe COVID-19 via genome-scale self-assembled DNA-barcoded protein libraries.

Pathogenic autoreactive antibodies that may be associated with life-threatening coronavirus disease 2019 (COVID-19) remain to be identified. Here, we show that self-assembled genome-scale libraries of full-length proteins covalently coupled to unique DNA barcodes for analysis by sequencing can be used for the unbiased identification of autoreactive antibodies in plasma samples. By screening 11,076 DNA-barcoded proteins expressed from a sequence-verified human ORFeome library, the method, which we named MIPSA (for Molecular Indexing of Proteins by Self-Assembly), allowed us to detect circulating neutralizing type-I and type-III interferon (IFN) autoantibodies in five plasma samples from 55 patients with life-threatening COVID-19. In addition to identifying neutralizing type-I IFN-α and IFN-ω autoantibodies and other previously known autoreactive antibodies in patient plasma, MIPSA enabled the detection of as yet unidentified neutralizing type-III anti-IFN-λ3 autoantibodies that were not seen in healthy plasma samples or in convalescent plasma from ten non-hospitalized individuals with COVID-19. The low cost and simple workflow of MIPSA will facilitate unbiased high-throughput analyses of protein-antibody, protein-protein and protein-small-molecule interactions.

Neutralizing IFNL3 Autoantibodies in Severe COVID-19 Identified Using Molecular Indexing of Proteins by Self-Assembly.

Unbiased antibody profiling can identify the targets of an immune reaction. A number of likely pathogenic autoreactive antibodies have been associated with life-threatening SARS-CoV-2 infection; yet, many additional autoantibodies likely remain unknown. Here we present Molecular Indexing of Proteins by Self Assembly (MIPSA), a technique that produces ORFeome-scale libraries of proteins covalently coupled to uniquely identifying DNA barcodes for analysis by sequencing. We used MIPSA to profile circulating autoantibodies from 55 patients with severe COVID-19 against 11,076 DNA-barcoded proteins of the human ORFeome library. MIPSA identified previously known autoreactivities, and also detected undescribed neutralizing interferon lambda 3 (IFN-λ3) autoantibodies. At-risk individuals with anti- IFN-λ3 antibodies may benefit from interferon supplementation therapies, such as those currently undergoing clinical evaluation.

HIV/AIDS and drug policy: a new approach for law enforcement.

While law enforcement often plays a deleterious role in furthering the spread of HIV/AIDS, there are also opportunities for it to promote health and reduce risky behaviour. The following article by Tom Lloyd summarizes an AIDS 2010 panel discussion, which he moderated, on the steps that law enforcement leadership could take in that regard.

The Penn State Heart Assistant: A pilot study of a web-based intervention to improve self-care of heart failure patients.

The Penn State Heart Assistant, a web-based, tablet computer-accessed, secure application was developed to conduct a proof of concept test, targeting patient self-care activities of heart failure patients including daily medication adherence, weight monitoring, and aerobic activity. Patients (n = 12) used the tablet computer-accessed program for 30 days-recording their information and viewing a short educational video. Linear random coefficient models assessed the relationship between weight and time and exercise and time. Good medication adherence (66% reporting taking 75% of prescribed medications) was reported. Group compliance over 30 days for weight and exercise was 84 percent. No persistent weight gain over 30 days, and some indication of weight loss (slope of weight vs time was negative (-0.17; p value = 0.002)), as well as increased exercise (slope of exercise vs time was positive (0.08; p value = 0.04)) was observed. This study suggests that mobile technology is feasible, acceptable, and has potential for cost-effective opportunities to manage heart failure patients safely at home.

Clinical workflow and applicability of electrophysiological cardiovascular magnetic resonance-guided radiofrequency ablation of isthmus-dependent atrial flutter.

Aims: To determine safety and efficacy of electrophysiological cardiovascular magnetic resonance (EP-CMR)-guided radiofrequency (RF) ablation in patients with typical right atrial flutter in a routine clinical setting. Methods and results: Thirty patients with typical right atrial flutter underwent clinically indicated EP-CMR-guided cavotricuspid isthmus ablation. EP-CMR protocols included pre- and post-ablation CMR imaging (whole heart, T2-weighted, and early-/late-gadolinium enhancement) together with electroanatomic mapping of the right atrium. Coronary sinus cannulation time and total ablation procedure duration were used as performance measures to determine the learning experience of the EP-CMR interventionalist and for comparison with conventional, fluoroscopy-guided atrial flutter ablation. Procedural safety and success rates were evaluated at 1 week and 3 months follow-up. Safety and success rates of EP-CMR were similar to conventional flutter ablations (primary success rate, 93% vs. 100%; recurrence rate, 0% vs. 3%, respectively). EP-CMR procedure duration indicated a learning experience (first vs. last six patients, 54.2 ± 23.1 vs. 29.7 ± 20.0 min) and the minimum number of procedures needed to achieve a level of competency was n = 12. An isthmus angle <110° and the presence of pouch-like isthmus anatomy were indicative of significantly prolonged EP-CMR procedure duration. CMR-defined ablation lesion size was not associated with total RF-ablation time or RF-induced maximum temperature. Conclusion: In a routine clinical setting, EP-CMR demonstrated its safety and high efficacy for the treatment of typical right atrial flutter with performance and outcome measures similar to conventional, fluoroscopy-guided flutter ablation. Hence, EP-CMR represents a valid alternative to conventional right atrial flutter ablation.

A novel method to correctly place the fasciotomy incision for decompression of the anterior and peroneal compartments of the leg.

UNLABELLED: Incorrectly placed fasciotomy incisions can lead to catastrophic complications in compartment syndrome. Two distinctly different techniques are widely practiced to decompress the anterior and peroneal compartments. In one technique the anterior compartment is decompressed directly, and then the peroneal via the inter-muscular septum, avoiding the peroneal perforators. The second technique relies on surface anatomy landmarks to place the skin incision immediately over the inter-muscular septum, and then the respective fascial envelopes are incised separately. A study in healthy active volunteers was conducted to explore the feasibility of a new technique for the placing the incision very accurately over the inter-muscular septum and so avoiding perforator vessels. Hypothesis The inter-muscular septum can be reliably identified using hand-held ultrasound, and confirmed with MRI. METHODS: Fourteen healthy active volunteers underwent hand-held ultrasound to identify the antero-lateral inter-muscular septum in the left lower limb, which was then marked using cod liver oil capsules. The positions of the anterior, septal and peroneal perforators were then identified using hand-held Doppler, and marked in the same way. MRI was then used to measure the relationship between the surface land marks, the septum (compared to its US position), and the relationship of the perforators themselves. RESULTS: Hand held ultrasound was successful in identifying the position of the inter-muscular septum in healthy volunteers, as confirmed on MRI scanning. The position and number of peroneal and anterior perforators proved very variable. Direct decompression of the anterior compartment would result in the loss of all anterior perforators in all subjects. Decompression with the skin incision over the inter-muscular septum would not jeopardise any peroneal muscular perforators. CONCLUSION: This new technique enables decompression both the anterior and peroneal compartments through an accurately placed incision, sparing the greatest number of perforators. Two brief case histories in which the technique was used are presented.

RF induced energy for partially implanted catheters: a computational study.

Magnetic Resonance Imaging (MRI) is a radiological imaging technique widely used in clinical practice. MRI has been proposed to guide the catheters for interventional procedures, such as cardiac ablation. However, there are risks associated with this procedure, such as RF-induced heating of tissue near the catheters. The aim of this study is to develop a quantitative RF-safety method for patients with partially implanted leads at 64 MHz. RF-induced heating is related to the electric field incident along the catheter, which in turns depends on several variables, including the position of the RF feeding sources and the orientation of the polarization, which are however often unknown. This study evaluates the electric field profile along the lead trajectory using simulations with an anatomical human model landmarked at the heart. The energy absorbed in the volume near the tip of ageneric partially implanted lead was computed for all source positions and field orientation. The results showed that varying source positions and field orientation may result in changes of up to 18% for the E-field magnitude and up to 60% for the 10g-averaged specific absorption rate (SAR) in the volume surrounding the tip of the lead.

Assessing the Electromagnetic Fields Generated By a Radiofrequency MRI Body Coil at 64 MHz: Defeaturing Versus Accuracy.

GOAL: This study aims at a systematic assessment of five computational models of a birdcage coil for magnetic resonance imaging (MRI) with respect to accuracy and computational cost. METHODS: The models were implemented using the same geometrical model and numerical algorithm, but different driving methods (i.e., coil "defeaturing"). The defeatured models were labeled as: specific (S2), generic (G32, G16), and hybrid (H16, [Formula: see text]). The accuracy of the models was evaluated using the "symmetric mean absolute percentage error" ("SMAPE"), by comparison with measurements in terms of frequency response, as well as electric ( ||→E||) and magnetic ( || →B ||) field magnitude. RESULTS: All the models computed the || →B || within 35% of the measurements, only the S2, G32, and H16 were able to accurately model the ||→E|| inside the phantom with a maximum SMAPE of 16%. Outside the phantom, only the S2 showed a SMAPE lower than 11%. CONCLUSIONS: Results showed that assessing the accuracy of || →B || based only on comparison along the central longitudinal line of the coil can be misleading. Generic or hybrid coils - when properly modeling the currents along the rings/rungs - were sufficient to accurately reproduce the fields inside a phantom while a specific model was needed to accurately model ||→E|| in the space between coil and phantom. SIGNIFICANCE: Computational modeling of birdcage body coils is extensively used in the evaluation of radiofrequency-induced heating during MRI. Experimental validation of numerical models is needed to determine if a model is an accurate representation of a physical coil.

Urinary free cortisol increases in adolescent caucasian females during perimenarche.

Urinary free cortisol (UFC) excretion has been thought to be constant during female reproductive maturation when normalized for body surface area. We sought to determine whether there are longitudinal changes in urinary free cortisol excretion during perimenarche in adolescent females. We performed a longitudinal study of 24-h UFC excretion obtained at 6-month intervals over a 4-yr period in a cohort of 112 adolescent non-Hispanic white perimenarchal females from south central Pennsylvania. The overall mean values (mean +/- SD) for UFC/24 h for all measurements between ages 12 and 17 yr was 67.4 +/- 43.8 micro g/24 h (to convert to nanomoles per day, multiply by 2.759). In our model, we found a significant positive association between UFC excretion with both gynecological age (P = 0.002) and chronological age (P = 0.0001). For every incremental increase in Tanner stage, the UFC/BSA increased by 3.0 microg/24 h per square meter. Correcting the UFC values by both creatinine and BSA creates a fairly constant number (6.3 +/- 3.1 microg/mg per square meter per 24 h) over the age range 12-17 yr represented in this study. An increase in cortisol excretion may be part of normal reproductive maturation.

Femoral bone structural geometry adapts to mechanical loading and is influenced by sex steroids: the Penn State Young Women's Health Study.

We used 10 years of longitudinal data from Penn State Young Women's Health Study to explore predictors of adult bone structural geometry and strength. One hundred twelve participants were enrolled in the study at age 12. We report findings on the 76 participants who remained in the study for 10 years. Measurements were recorded biannually for the first 4 years and annually thereafter. Proximal femur DXA scans (Hologic QDR 2000) were taken from 17-22 years and analyzed using a hip structure analysis program to assess areal bone mineral density (BMD, g/cm2), subperiosteal width, cortical thickness, bone cross-sectional area (CSA), and section modulus (Z) at the narrow neck and femoral shaft. Total body lean mass (g) was measured with DXA total body scans. Nutrition, anthropometry, and sex steroids [testosterone (T) and estradiol (E2)] were measured from ages 12-22 years. Multiple regression models were used to assess predictors of change in bone variables (17-22 years) and absolute bone values (average of age 21 and 22 years, n = 79). Neck Z (+3.1%) and width (+1.3%), but not BMD (-0.8%), increased significantly from age 17 to 22 years. At the shaft, all variables increased (+1.0-4.0%, P < 0.01). After controlling for baseline (age 17) height, weight and bone measurement, weight change (neck) or lean mass (shaft), and age of menarche were the primary predictors of change in bone strength. After controlling for height and weight, only lean mass predicted absolute young adult Z at both the neck (r2 = 0.48, P < 0.01) and the shaft (r2 = 0.67, P < 0.01). When lean mass was removed from the model, sports exercise score replaced lean mass as a predictor of Z at both neck (r2 = 0.40, P < 0.01) and shaft (r2 = 0.60, P < 0.01) sites. For neck and shaft cortical thickness and BMD, both estradiol and sports score/lean mass were positive predictors (r2 = 0.15-0.40, P < 0.01). For neck bone width, testosterone levels (negative) and lean mass (positive) were significant (r2 = 0.48). Results were similar for each geometric variable at the shaft site. These data suggest that bone adapts its bending strength primarily to mechanical loading (represented by lean mass and sports exercise score) and that sex steroids are associated with bone geometric structure.

Oral contraceptive use by teenage women does not affect body composition.

OBJECTIVE: To assess the effect of oral contraceptive (OC) use during adolescence on body composition parameters and cardiovascular disease risk factors. METHODS: We used 9 years of longitudinal data from 66 non-Hispanic white females who were 12 years old at study entry in 1990, and who were subsequently classified either as OC users or nonusers. The OC users (n = 39) used OCs for a minimum of 6 months, were still using at age 21, and had used OCs, on average, for 28 months. The nonusers (n = 27) never used OCs. Individuals who started and then stopped using OCs before age 21 or used OCs for less than 6 months were excluded from these analyses. Cardiolipoprotein profiles were obtained from fasting blood samples (from age 16 to 21), and body composition measurements were made by dual energy x-ray absorptiometry (from age 12.5 to 21). Longitudinal models were used to examine changes in body composition patterns and in cardiolipoprotein patterns. RESULTS: Between ages 12.5 and 21, gains by OC users and nonusers in height, weight, body mass index (BMI), and percent body fat were not significantly different. However, between ages 16 and 21, the OC users had significantly greater increases in total serum cholesterol, serum low-density cholesterol, and serum triglycerides than did the nonusers. CONCLUSION: The use of OCs in young women is associated with less favorable blood lipid patterns, but is not associated with weight gain or increased body fat. The long-term effects of the alteration in the lipid profiles are unknown.

Adolescent Caucasian mothers have reduced adult hip bone density.

OBJECTIVE: To determine the long-term effect of full term teen pregnancy on peak hip bone mineral density. DESIGN: Longitudinal observational study. SETTING: Academic clinical research center. PATIENT(S): Sixteen non-Hispanic white females: 4 cases and 12 matched controls who are part of The Penn State Young Women's Health Study and have been studied from ages 12 to 21. MAIN OUTCOME MEASURES: Four of the subjects had uncomplicated full-term pregnancies between ages 16.5 and 19.5 years. INTERVENTION(S): The cases and controls were matched for body mass index at age 12 years, total body bone mineral content at age 12 years, age of menarche, and sports-exercise score during ages 12-18 years. They were then compared with respect to bone measures, cardiovascular disease risk factors, and endocrine profiles at ages 19-21 years. RESULT(S): The four teen mothers had significantly lower adult hip bone mineral density than did the controls (0.89 g/cm(2) vs. 0.99 g/cm(2); P=.03). The reproductive hormone patterns of the cases were not statistically significantly different from those of the controls, yet the cases showed a postmenopausal blood lipid pattern. CONCLUSION(S): The persistent reduction in hip bone mineral density of the cases is consistent with significantly increased risk of future hip fracture.