An Unusual Case of Microcystic Serous Cystadenoma in a 19-Year-Old Male Patient

Introduction

Microcystic serous cystadenomas are uncommon, benign neoplasms rarely known to progress to malignancy. They are typically asymptomatic and inadvertently discovered during imaging for another unrelated condition. When discovered, they are commonly found in females over 60 years of age.

Case Presentation

In this case report, we examine a unique presentation of a serous cystadenoma discovered when a 19-year-old male presented with symptoms of abdominal pain, nausea, and vomiting.

Conclusion

Previous studies on serous cystadenomas in a younger male demographic are rare. Therefore, this study will provide additional insight into the signs, symptoms, diagnosis, and management of cystadenomas in young patients.

Rezūm water vapor therapy in multimorbid patients with urinary retention and catheter dependency

BACKGROUND

Water vapor thermal therapy (Rezūm) is a minimally invasive treatment for benign prostatic enlargement (BPE). We report on safety and efficacy of this method for treatment of recurrent urinary retention and relief of catheter dependency owing to BPE in multimorbid patients, considered unfit for surgery.

METHODS

We retrospectively evaluated 136 patients with recurrent urinary retention who underwent water vapor therapy in an ambulatory setting with periprostatic block and optional sedation between 11/2017 and 02/2021 in three urological departments. The objective was successful catheter withdrawal and continuing catheter independency after 3- and 12-months following treatment.

RESULTS

Mean patient age was 80.3 years (±7.8), mean prostate volume 54 ml (±27.3), and mean catheter dependency before treatment was 4.8 months (±6.0). ASA classification was a followed: II: 10%, III: 71%, and IV: 19%. All procedures were performed successfully in an ambulatory setting. Perioperative complications were infrequent and minor (Clavien-Dindo Grade 1-2) and included haematuria in 4.4% and urinary tract infection in 3.9% of all cases. A total of 103 patients (78.6%) were able to void spontaneously after a median of 31 days. No significant differences in age, prostate volume, duration of catheter dependency, vapor injections, and ASA score were found between patients with successful or unsuccessful outcome. The mean follow-up period was 6.1 months (±5.9, range 1-22 months). A 3-month follow-up was available for 77 patients (75%) and 34 patients (33%) were followed for 12 months. After 3 and 12 months, 93.5 and 91% of patients remained catheter independent. Fifteen patients (11%) died during follow-up, with a mean overall survival of 7.7 months (±4.7).

CONCLUSIONS

Water vapor therapy may prove to be a useful, minimally invasive treatment in a multimorbid population with catheter dependency after urinary retention, secondary to BPE, considered at highest risk or unfit for surgery. Future studies are warranted.

Nitrogen inputs best predict farm field nitrate leaching in the Willamette Valley, Oregon

Nitrate leaching is an important yet difficult to manage contribution to groundwater and surface water contamination in agricultural areas. We examine 14 farm fields over a four year period (2014-2017) in the southern Willamette Valley, providing 53 sets of annual, field-level agricultural performance metrics related to nitrogen (N), including fertilizer inputs, crop harvest outputs, N use efficiency (NUE), nitrate-N leaching and surplus N. Crop-specific nitrate-N leaching varied widely from 10 kg N ha-1yr-1 in hazelnuts to >200 kg N ha-1yr-1 in peppermint. Averaging across all sites and years, most leaching occurred during fall (60%) and winter (32%). Overall NUE was 57%. We used a graphical approach to explore the relationships between N inputs, surplus, crop N harvest removal and NUE by crop type. The blueberry site had high inputs and surplus, peppermint had high inputs but also high crop N removal and NUE and thus lower surplus, and most wheat crops had high NUE and evidence of using soil N. Annual N surplus was not well correlated with leaching, and leaching varied more by crop type and inputs. Grass seed and hazelnuts, which are dominant crop types in the southern Willamette Valley, were intermediate in terms of NUE, leaching and surplus. Of all performance metrics, N input was most closely aligned with field-level crop N harvest and nitrate leaching, therefore optimizing N inputs may well inform local efforts to reduce groundwater nitrate contamination.

P6203Intramyocellular lipid saturation as a new metabolic biomarker

Background

Endurance trained athletic healthy volunteers (Athl-HV) and type 2 diabetes patients (T2D) have higher levels of lipids in their skeletal myocytes compared to healthy controls. Despite apparently similar metabolic storage, they are at opposite ends of insulin sensitivity and cardio-metabolic risk.

Purpose

We investigated if the degree of saturation of the IntraMyoCellular Lipids (IMCL) will differentiate Athl-HV from T2D; and explored if an exercise intervention will induce changes in the IMCL saturation.

Methods

Male, age matched Athl-HV and T2D were enrolled (n=25/group). Athl-HV had ≥5 years endurance training, T2D were sedentary. Subjects were studied at baseline and after an exercise intervention (4 week deconditioning in Athl-HV and supervised bike training at ≥65% of peakVO2, 5 hours/week x 8 weeks in T2D). All subjects underwent cardio-pulmonary exercise testing (CPET), blood sampling for insulin sensitivity (QUICKI*) and single voxel 1H-magnetic resonance spectroscopy (1H-MRS) of the right vastus lateralis. 1H-MRS was acquired on 3T Philips Achieva with a 16-channel coil, point-resolved spectroscopy, variable pulse power and optimized relaxation delay water suppression and analysed in LCModel. We derived fractional lipid mass (fLM) and fractions of saturated (fSL) and unsaturated (fUL) lipids. Data were analysed by t tests, shown as mean±SEM, statistical significance p<0.05.

Results

CPET and insulin sensitivity are presented in Table 1. T2D had higher fLM in the skeletal muscle compared to Athl-HV, at baseline (p=0.003) and after the exercise intervention (p=0.009), Figure 1A. At baseline, T2D had a different phenotype with a lower fSL and higher fUL compared to Athl-HV (82±3 vs 88±1% and 18±3 vs 12±1%, p=0.02 for both). Whilst deconditioning did not attract any significant changes in either fSL or fUL in Athl-HV (88±1 to 86±1% and 12±1 to 14±1, p=0.2), in contrast, with exercise training T2D significantly increased fSL (82±3 to 88±1%) and decreased their fUL (18±3 to 12±1%) (both p=0.01). Figure 1B and 1C.

CPET and insulin sensitivity results Athl-HV Baseline Athl-HV Deconditioning p value T2D Baseline T2D After Training p value VO2 peak, (mL/kg/min) 45.0±0.9† 41.7±0.9‡ <0.0001 23.6±0.6† 30.3±0.6‡ <0.0001 QUICKI* 0.346±0.002† 0.343±0.003‡ 0.2 0.308±0.004† 0.317±0.004‡ 0.02 *QUICKI: Quantitative Insulin Sensitivity Check Index; †Athl-HV vs T2D at baseline p≤0.001, ‡Athl-HV vs T2D after exercise intervention p≤0.001.

Figure 1

Conclusion

We demonstrate for the first time, in vivo, significant differences in the IMCL amount and saturation between Athl-HV and T2D. IMCL saturation was changed by exercise training in T2D to mirror the phenotype seen in Athl-HV uncovering a new, independent biomarker of improved cardio-metabolic health.

Acknowledgement/Funding

British Heart Foundation Project Grant no. PG/15/88/31780

GABA and glutamate moderate beta-amyloid related functional connectivity in cognitively unimpaired old-aged adults

Background

Effects of beta-amyloid accumulation on neuronal function precede the clinical manifestation of Alzheimer's disease (AD) by years and affect distinct cognitive brain networks. As previous studies suggest a link between beta-amyloid and dysregulation of excitatory and inhibitory neurotransmitters, we aimed to investigate the impact of GABA and glutamate on beta-amyloid related functional connectivity.

Methods

29 cognitively unimpaired old-aged adults (age = 70.03 ± 5.77 years) were administered 11C-Pittsburgh Compound B (PiB) positron-emission tomography (PET), and MRI at 7 Tesla (7T) including blood oxygen level dependent (BOLD) functional MRI (fMRI) at rest for measuring static and dynamic functional connectivity. An advanced 7T MR spectroscopic imaging (MRSI) sequence based on the free induction decay acquisition localized by outer volume suppression’ (FIDLOVS) technology was used for gray matter specific measures of GABA and glutamate in the posterior cingulate and precuneus (PCP) region.

Results

GABA and glutamate MR-spectra indicated significantly higher levels in gray matter than in white matter. A global effect of beta-amyloid on functional connectivity in the frontal, occipital and inferior temporal lobes was observable. Interactive effects of beta-amyloid with gray matter GABA displayed positive PCP connectivity to the frontomedial regions, and the interaction of beta-amyloid with gray matter glutamate indicated positive PCP connectivity to frontal and cerebellar regions. Furthermore, decreased whole-brain but increased fronto-occipital and temporo-parietal dynamic connectivity was found, when GABA interacted with regional beta-amyloid deposits in the amygdala, frontal lobe, hippocampus, insula and striatum.

Conclusions

GABA, and less so glutamate, may moderate beta-amyloid related functional connectivity. Additional research is needed to better characterize their interaction and potential impact on AD.

•

Combined ultra-high fieldstrength FIDLOVS MRSI at 7 Tesla with 11C-PIB PET.

•

Assessment of gray matter specific levels of GABA and glutamate.

•

Identification of interactive effects of GABA, glutamate and beta-Amyloid.

•

GABA may moderate dysfunctional beta-Amyloid effects on pre-clinical brain pathology.

A Case Study of Acute Stimulant-induced Psychosis

Psychosis resulting from stimulant overuse is commonly observed in clinical practices today. This is in large part due to the significant increase in attention-deficit/hyperactive disorder (ADHD) diagnoses in recent years, the increase in methamphetamine trafficking, and the prevalence of stimulant use in the day-to-day activities by many of those living in today’s fast-paced society. The current inability to predict those users who will experience stimulant-induced psychosis from those users who will not needs further investigation.

In this case study, we examine why one particular stimulant user experiences stimulant-induced psychosis. We give an account of a patient with an acute psychotic episode admitted to the emergency room at a local hospital. During initial evaluation, it was discovered that he had been diagnosed with ADHD one month ago and that the onset of his symptoms was likely related to an overuse of amphetamines. The patient had no personal history or family history of any psychiatric or mood disorders. He had no history of recreational drug use prior to this incident, and had no history of seizures or head trauma. After appropriate pharmacological intervention with antipsychotics and psychological intervention, the patient showed gradual improvement over the next five days of his hospitalization. After the five days, he was allowed to be discharged.

We conclude with the cautionary advice that a patient’s susceptibility of experiencing stimulant-induced psychosis should be assessed before prescribing stimulants. In cases where stimulant use is not supervised by a physician, appropriate understanding of management of stimulant-induced psychosis is of utmost importance in order to provide the very best patient education and care.

Hallucinogen-persisting Perception Disorder in a 21-year-old Man

This is a case report of hallucinogen-persisting perception disorder in a 21-year-old man. Hallucinogen-persisting perception disorder, or acute hallucinogen-induced psychosis, is a rare disorder characterized by the presence of flashbacks of visual hallucinations as a result of previous hallucinogenic drug use. There is no standard of treatment, and management involves a combination of pharmaceuticals and lifestyle modifications. The combination of the rarity of the disorder along with the drastic impact this disorder has on a person's life makes this condition unique as compared to other substance-induced conditions.

Combination of surface and 'vertical' loop elements improves receive performance of a human head transceiver array at 9.4 T

Ultra-high-field (UHF, ≥7 T) human magnetic resonance imaging (MRI) provides undisputed advantages over low-field MRI (≤3 T), but its development remains challenging because of numerous technical issues, including the low efficiency of transmit (Tx) radiofrequency (RF) coils caused by the increase in tissue power deposition with frequency. Tight-fit human head transceiver (TxRx) arrays improve Tx efficiency in comparison with Tx-only arrays, which are larger in order to fit multi-channel receive (Rx)-only arrays inside. A drawback of the TxRx design is that the number of elements in an array is limited by the number of available high-power RF Tx channels (commonly 8 or 16), which is not sufficient for optimal Rx performance. In this work, as a proof of concept, we developed a method for increasing the number of Rx elements in a human head TxRx surface loop array without the need to move the loops away from a sample, which compromises the array Tx performance. We designed and constructed a prototype 16-channel tight-fit array, which consists of eight TxRx surface loops placed on a cylindrical holder circumscribing a head, and eight Rx-only vertical loops positioned along the central axis (parallel to the magnetic field B₀ ) of each TxRx loop, perpendicular to its surface. We demonstrated both experimentally and numerically that the addition of the vertical loops has no measurable effect on the Tx efficiency of the array. An increase in the maximum local specific absorption rate (SAR), evaluated using two human head voxel models (Duke and Ella), measured 3.4% or less. At the same time, the 16-element array provided 30% improvement of central signal-to-noise ratio (SNR) in vivo relative to a surface loop eight-element array. The novel array design also demonstrated an improvement in the parallel Rx performance in the transversal plane. Thus, using this method, both the Rx and Tx performance of the human head array can be optimized simultaneously.

Ultra-High Spatial Resolution, Multi-Energy CT using Photon Counting Detector Technology

Two ultra-high-resolution (UHR) imaging modes, each with two energy thresholds, were implemented on a research, whole-body photon-counting-detector (PCD) CT scanner, referred to as sharp and UHR, respectively. The UHR mode has a pixel size of 0.25 mm at iso-center for both energy thresholds, with a collimation of 32 × 0.25 mm. The sharp mode has a 0.25 mm pixel for the low-energy threshold and 0.5 mm for the high-energy threshold, with a collimation of 48 × 0.25 mm. Kidney stones with mixed mineral composition and lung nodules with different shapes were scanned using both modes, and with the standard imaging mode, referred to as macro mode (0.5 mm pixel and 32 × 0.5 mm collimation). Evaluation and comparison of the three modes focused on the ability to accurately delineate anatomic structures using the high-spatial resolution capability and the ability to quantify stone composition using the multi-energy capability. The low-energy threshold images of the sharp and UHR modes showed better shape and texture information due to the achieved higher spatial resolution, although noise was also higher. No noticeable benefit was shown in multi-energy analysis using UHR compared to standard resolution (macro mode) when standard doses were used. This was due to excessive noise in the higher resolution images. However, UHR scans at higher dose showed improvement in multi-energy analysis over macro mode with regular dose. To fully take advantage of the higher spatial resolution in multi-energy analysis, either increased radiation dose, or application of noise reduction techniques, is needed.

Dual Energy CT Kidney Stone Differentiation in Photon Counting Computed Tomography

This study evaluates the capabilities of a whole-body photon counting CT system to differentiate between four common kidney stone materials, namely uric acid (UA), calcium oxalate monohydrate (COM), cystine (CYS),and apatite (APA) ex vivo. Two different x-ray spectra (120 kV and 140 kV) were applied and two acquisition modes were investigated; The macro-mode generates two energy threshold based image-volumes and two energy bin based image-volumes. In the chesspattern-mode, however, four energy thresholds are applied. A virtual low energy image, as well as a virtual high energy image are derived from initial threshold-based images, while considering their statistically correlated nature. The energy bin based images of the macro-mode, as well as the virtual low and high energy image of the chesspattern-mode serve as input for our dual energy evaluation. The dual energy ratio of the individually segmented kidney stones were utilized to quantify the discriminability of the different materials. The dual energy ratios of the two acquisition modes showed high correlation for both applied spectra. Wilcoxon-rank sum tests and the evaluation of the area under the receiver operating characteristics curves suggest that the UA kidney stones are best differentiable from all other materials (AUC = 1.0), followed by CYS (AUC ≈ 0.9 compared against COM and APA). COM and APA, however, are hardly distinguishable (AUC between 0.63 and 0.76). The results hold true for the measurements of both spectra and both acquisition modes.

Renal Stone Characterization using High Resolution Imaging Mode on a Photon Counting Detector CT System

In addition to the standard-resolution (SR) acquisition mode, a high-resolution (HR) mode is available on a research photon-counting-detector (PCD) whole-body CT system. In the HR mode each detector consists of a 2x2 array of 0.225 mm × 0.225 mm subpixel elements. This is in contrast to the SR mode that consists of a 4x4 array of the same sub-elements, and results in 0.25 mm isotropic resolution at iso-center for the HR mode. In this study, we quantified ex vivo the capabilities of the HR mode to characterize renal stones in terms of morphology and mineral composition. Forty pure stones - 10 uric acid (UA), 10 cystine (CYS), 10 calcium oxalate monohydrate (COM) and 10 apatite (APA) - and 14 mixed stones were placed in a 20 cm water phantom and scanned in HR mode, at radiation dose matched to that of routine dual-energy stone exams. Data from micro CT provided a reference for the quantification of morphology and mineral composition of the mixed stones. The area under the ROC curve was 1.0 for discriminating UA from CYS, 0.89 for CYS vs COM and 0.84 for COM vs APA. The root mean square error (RMSE) of the percent UA in mixed stones was 11.0% with a medium-sharp kernel and 15.6% with the sharpest kernel. The HR showed qualitatively accurate characterization of stone morphology relative to micro CT.

Evaluation of transmit efficiency and SAR for a tight fit transceiver human head phased array at 9.4 T

Ultra-high field (UHF, ≥7 T) tight fit transceiver phased arrays improve transmit (Tx) efficiency (B₁⁺ /√P) in comparison with Tx-only arrays, which are usually larger to fit receive (Rx)-only arrays inside. One of the major problems limiting applications of tight fit arrays at UHFs is the anticipated increase of local tissue heating, which is commonly evaluated by the local specific absorption rate (SAR). To investigate the tradeoff between Tx efficiency and SAR when a tight fit UHF human head transceiver phased array is used instead of a Tx-only/Rx-only RF system, a single-row eight-element prototype of a 400 MHz transceiver head phased array was constructed. The Tx efficiency and SAR of the array were evaluated and compared with that of a larger Tx-only array, which could also be used in combination with an 18-channel Rx-only array. Data were acquired on the Siemens Magnetom whole body 9.4 T human MRI system. Depending on the head size, positioning and the RF shim strategy, the smaller array provides from 11 to 23% higher Tx efficiency. In general, the Tx performance, evaluated as B₁⁺ /√SAR, i.e. the safety excitation efficiency (SEE), is also not compromised. The two arrays provide very similar SEEs evaluated over 1000 random RF shim sets. We demonstrated that, in general, the tight fit transceiver array improves Tx performance without compromising SEE. However, in specific cases, the SEE value may vary, favoring one of the arrays, and therefore must be carefully evaluated.

Increased pregenual anterior cingulate glucose and lactate concentrations in major depressive disorder

There is ample evidence that glucose metabolism in the pregenual anterior cingulate cortex (PACC) is increased in major depressive disorder (MDD), whereas it is still unknown whether glucose levels per se are also elevated. Elevated cerebrospinal fluid (CSF) lactate concentrations in MDD patients might indicate that increased glycolytical metabolization of glucose to lactate in astrocytes either alone or in conjunction with mitochondrial dysfunction results in an accumulation of lactate and contributes to pathophysiological mechanisms of MDD. However, until now, no study investigated in vivo PACC glucose and lactate levels in MDD. Proton magnetic resonance spectroscopy was therefore used to test the hypothesis that patients with MDD have increased PACC glucose and lactate levels. In 40 healthy and depressed participants, spectra were acquired from the PACC using a maximum echo J-resolved spectroscopy protocol. Results show significant increases of glucose and lactate in patients, which are also associated with depression severity. These findings indicate impaired brain energy metabolism in MDD with increased fraction of energy utilization via glycolysis and reduced mitochondrial oxidative clearance of lactate. Targeting these metabolic disturbances might affect the balance of metabolic pathways regulating neuronal energetics and result in an attenuation of the elevated basal activity of brain regions within the neural circuitry of depression.

(1) H MRS in the human spinal cord at 7 T using a dielectric waveguide transmitter, RF shimming and a high density receive array

Multimodal MRI is the state of the art method for clinical diagnostics and therapy monitoring of the spinal cord, with MRS being an emerging modality that has the potential to detect relevant changes of the spinal cord tissue at an earlier stage and to enhance specificity. Methodological challenges related to the small dimensions and deep location of the human spinal cord inside the human body, field fluctuations due to respiratory motion, susceptibility differences to adjacent tissue such as vertebras and pulsatile flow of the cerebrospinal fluid hinder the clinical application of (1) H MRS to the human spinal cord. Complementary to previous studies that partly addressed these problems, this work aims at enhancing the signal-to-noise ratio (SNR) of (1) H MRS in the human spinal cord. To this end a flexible tight fit high density receiver array and ultra-high field strength (7 T) were combined. A dielectric waveguide and dipole antenna transmission coil allowed for dual channel RF shimming, focusing the RF field in the spinal cord, and an inner-volume saturated semi-LASER sequence was used for robust localization in the presence of B1 (+) inhomogeneity. Herein we report the first 7 T spinal cord (1) H MR spectra, which were obtained in seven independent measurements of 128 averages each in three healthy volunteers. The spectra exhibit high quality (full width at half maximum 0.09 ppm, SNR 7.6) and absence of artifacts and allow for reliable quantification of N-acetyl aspartate (NAA) (NAA/Cr (creatine) 1.31 ± 0.20; Cramér-Rao lower bound (CRLB) 5), total choline containing compounds (Cho) (Cho/Cr 0.32 ± 0.07; CRLB 7), Cr (CRLB 5) and myo-inositol (mI) (mI/Cr 1.08 ± 0.22; CRLB 6) in 7.5 min in the human cervical spinal cord. Thus metabolic information from the spinal cord can be obtained in clinically feasible scan times at 7 T, and its benefit for clinical decision making in spinal cord disorders will be investigated in the future using the presented methodology. Copyright © 2016 John Wiley & Sons, Ltd.

A High-Resolution Imaging Technique using a Whole-body, Research Photon Counting Detector CT System

A high-resolution (HR) data collection mode has been introduced to the whole-body, research photon-counting-detector CT system installed in our laboratory. In this mode, 64 rows of 0.45 mm × 0.45 mm detectors pixels were used, which corresponded to a pixel size of 0.225 mm × 0.225 mm at the iso-center. Spatial resolution of this HR mode was quantified by measuring the MTF from a scan of a 50 micron wire phantom. An anthropomorphic lung phantom, cadaveric swine lung, temporal bone and heart specimens were scanned using the HR mode, and image quality was subjectively assessed by two experienced radiologists. Comparison of the HR mode images against their energy integrating system (EID) equivalents using comb filters was also performed. High spatial resolution of the HR mode was evidenced by the MTF measurement, with 15 lp/cm and 20 lp/cm at 10% and 2% MTF. Images from anthropomorphic phantom and cadaveric specimens showed clear delineation of small structures, such as lung vessels, lung nodules, temporal bone structures, and coronary arteries. Temporal bone images showed critical anatomy (i.e. stapes superstructure) that was clearly visible in the PCD system but hardly visible with the EID system. These results demonstrated the potential application of this imaging mode in lung, temporal bone, and vascular imaging. Other clinical applications that require high spatial resolution, such as musculoskeletal imaging, may also benefit from this high resolution mode.

Navigator based respiratory gating during acquisition and preparation phases for proton liver spectroscopy at 3 T

Proton magnetic resonance spectroscopy ((1)H MRS) enables the non-invasive investigation of the human liver; however, because of technical difficulties it is not regularly used for diagnosis of liver diseases in clinical routine. Breathing motion is one of the major challenges, as it decreases spectral quality and leads to misplacement of the spectroscopic voxel. To overcome this problem, real-time navigator gating for spectral acquisition and preparation steps (B0 shimming, water frequency determination, receiver gain optimization, and water suppression) combined with short TE , optimized first order projection based B0 shimming, water suppression, and inner-volume saturated point resolved spectroscopy (PRESS) at 3 T is suggested. Simultaneous lipid and trimethylamine quantification is demonstrated by means of phantom, volunteer, and representative patient measurements. Precise localization of the voxel despite respiratory motion, increased spectral quality (higher signal-to-noise ratio and reduced linewidth) compared with measurements without respiratory gating, and the possibility of acquiring data without additional subject instructions regarding breathing enable robust and accurate liver (1)H MRS measurements with this novel acquisition protocol.

(1)H-MR spectroscopy in the human spinal cord

SUMMARY

MR spectroscopy allows insight into the chemical composition of human tissue noninvasively. Thereby it can help to better characterize pathologic processes affecting the spinal cord and may provide important clinical markers for differential diagnosis. However, due to technical challenges, it has been rarely applied to the spinal cord. The aim of this review was to summarize the technical development and clinical studies using MR spectroscopy in the spinal cord. Main challenges of applying MR spectroscopy in the spinal cord are discussed, and a description of a state-of-the-art scan protocol is given. In conclusion, MR spectroscopy is a promising tool for research and diagnosis of the spinal cord because it can provide additional information complementary to other noninvasive imaging methods. However, the application of MR spectroscopy in the spinal cord is not straightforward, and great care is required to attain optimal spectral quality.

J-refocused 1H PRESS DEPT for localized 13C MR spectroscopy

Proton point-resolved spectroscopy (PRESS) localization has been combined with distortionless enhanced polarization transfer (DEPT) in multinuclear MRS to overcome the signal contamination problem in image-selected in vivo spectroscopy (ISIS)-combined DEPT, especially for lipid detection. However, homonuclear proton scalar couplings reduce the DEPT enhancement by modifying the spin coherence distribution under J modulation during proton PRESS localization. Herein, a J-refocused proton PRESS-localized DEPT sequence is presented to obtain simultaneously enhanced and localized signals from a large number of metabolites by in vivo (13) C MRS. The suppression of J modulation during PRESS and the substantial recovery of signal enhancement by J-refocused PRESS-localized DEPT were demonstrated theoretically by product operator formalism, numerically by the spin density matrix simulations for different scalar coupling conditions, and experimentally with a glutamate phantom at various TEs, as well as a colza oil phantom. The application of the sequence for localized detection of saturated and unsaturated fatty acids in the calf bone marrow and skeletal muscle of healthy subjects yielded high signal enhancements simultaneously obtained for all components.

Successful bridge to recovery using a microaxial blood pump in a patient with electrical storm and cardiogenic shock

A 59-year-old patient with dilated cardiomyopathy and incessant ventricular tachycardia leading to progressive cardiogenic shock is presented. Due to hemodynamic instability, high dose catecholamines were required in addition to the implantation of an intraaortic balloon pump (IABP), which, however, appeared to further augment the frequency and duration of ventricular tachycardias. The implantation of a microaxial blood pump allowed catecholamine administration to be terminated, thereby, ending this vicious circle of catecholamine-driven electrical storm. Within 5 days, the patient was hemodynamically stabilized and kidney and liver function recovered with the support of intensive antiarrhythmic therapy (amiodarone, mexiletine, sotalol). During a 24-month follow-up, the patient had no further ICD shocks and no rehospitalization was required for treatment of congestive heart failure.

In-vivo assessment of tissue metabolite levels using 1H MRS and the Electric REference To access In vivo Concentrations (ERETIC) method

Quantitative values of metabolite concentrations in (1)H magnetic resonance spectroscopy have been obtained using the Electric REference To access In vivo Concentrations (ERETIC) method, whereby a synthetic reference signal is injected during the acquisition of spectra. The method has been improved to enable quantification of metabolite concentrations in vivo. Optical signal transmission was used to eliminate random fluctuations in ERETIC signal coupling to the receiver coil due to changes in position of cables and highly dielectric human tissue. Stability and reliability of the signal were tested in vitro, achieving stability with a mean error of 2.83%. Scaling of the signal in variable loading conditions was demonstrated and in-vivo measurements of brain were acquired on a 3T Philips system using a transmit/receive coil. The quantitative brain water and metabolite concentration values are in good agreement with those in the literature.

Relationship between coronary microvascular dysfunction and cardiac energetics impairment in type 1 diabetes mellitus

BACKGROUND

Asymptomatic subjects with diabetes mellitus have an impaired cardiac energetics status that may play a significant role in the development of heart failure. In the present study, we assessed the role of microvascular dysfunction in the development of impaired cardiac energetics in subjects with type 1 diabetes mellitus.

METHODS AND RESULTS

Twenty-five asymptomatic subjects with type 1 diabetes mellitus (mean age +/-1 SD 33+/-8 years) and 26 age-, sex-, and body mass index-matched healthy control subjects (32+/-8 years old) were recruited into the study. The type 1 diabetes mellitus subjects were divided into 2 age-matched groups (newly diagnosed [<5 years] and longer-duration [>10 years] diabetes) to assess the impact of microvascular disease. All subjects had an echocardiogram and an exercise ECG performed, followed by magnetic resonance spectroscopy and stress magnetic resonance imaging. Compared with healthy control subjects, the phosphocreatine/gamma-ATP ratio was reduced significantly both in subjects with longer-term (2.1+/-0.5 versus 1.5+/-0.4, P<0.000) and newly diagnosed (2.1+/-0.5 versus 1.6+/-0.2, P<0.000) diabetes. The phosphocreatine/gamma-ATP ratio was similar in newly diagnosed diabetes subjects and those with longer-term disease (1.6+/-0.2 versus 1.5+/-0.4, P=0.32). The mean myocardial perfusion reserve index in the longer-term type 1 diabetes mellitus subjects was significantly lower than in healthy control subjects (1.7+/-0.6 versus 2.3+/-0.4, P=0.005). On univariate analysis, there was no significant correlation of phosphocreatine/gamma-ATP ratio with myocardial perfusion reserve index (r=0.21, P=0.26).

CONCLUSIONS

We demonstrate that young subjects with uncomplicated type 1 diabetes mellitus have impaired myocardial energetics irrespective of the duration of diabetes and that the impaired cardiac energetics status is independent of coronary microvascular function. We postulate that impairment of cardiac energetics in these subjects primarily results from metabolic dysfunction rather than microvascular impairment.

Diffusion-weighted imaging of the entire spinal cord

In spite of their diagnostic potential, the poor quality of available diffusion-weighted spinal cord images often restricts clinical application to cervical regions, and improved spatial resolution is highly desirable. To address these needs, a novel technique based on the combination of two recently presented reduced field-of-view approaches is proposed, enabling high-resolution acquisition over the entire spinal cord. Field-of-view reduction is achieved by the application of non-coplanar excitation and refocusing pulses combined with outer volume suppression for removal of unwanted transition zones. The non-coplanar excitation is performed such that a gap-less volume is acquired in a dedicated interleaved slice order within two repetition times. The resulting inner volume selectivity was evaluated in vitro. In vivo diffusion tensor imaging data on the cervical, thoracic and lumbar spinal cord were acquired in transverse orientation in each of four healthy subjects. An in-plane resolution of 0.7 x 0.7 mm(2) was achieved without notable aliasing, motion or susceptibility artifacts. The measured mean +/- SD fractional anisotropy was 0.69 +/- 0.11 in the thoracic spinal cord and 0.75 +/- 0.07 and 0.63 +/- 0.08 in cervical and lumbar white matter, respectively.

Embryonic chicken trachea as a new in vitro model for the investigation of mucociliary particle clearance in the airways

Mucociliary clearance (MC) is an important defense mechanism of the respiratory system to eliminate inhaled and possibly noxious particles from the lung. Although the principal mechanics of MC seem to be relatively clear there are still open questions regarding the long-term clearance of particles. Therefore, we have developed a new set-up based on embryonic chicken trachea (ECT) to investigate mucociliary particle clearance in more detail. ECT was placed in an incubation chamber after carbon particles were applied and tracked using optical microscopy. The aim of the study was to validate this model by investigating the impact of temperature, humidity and drugs on particle transport rates. Particles were transported reproducibly along the trachea and clearance velocity (2.39 +/- 0.25) mm/min was found to be in accordance to data reported in literature. Variation in temperature resulted in significantly reduced MC: (0.40 +/- 0.12) mm/min (20 degrees C); (0.42 +/- 0.10) mm/min (45 degrees C). Decreasing humidity (99-60%) had no significant effect on MC, whereas reduction to 20% humidity showed a significant influence on particle clearance. The use of different cilio- and muco-active drugs (propranolol, terbutalin, N-acetylcysteine) resulted in altered MC according to the pharmacological effect of the substances: a concentration dependent decrease of MC was found for Propranolol. From our results we conclude that this model can be employed to investigate MC of particles in more detail. Hence, the model may help to understand and identify decisive physico-chemical parameters for MC and to answer open questions regarding the long-term clearance phenomenon.

Design of broadband RF pulses with polynomial-phase response

The achievable bandwidth of common linear-phase RF pulses is limited by the maximum feasible B1 amplitude of the MR system. It has been shown previously, that this limitation can be circumvented by overlaying a quadratic phase in the frequency domain, which spreads the power across the pulse duration. Quadratic-phase RF pulses are near optimal in terms of achieving minimal B1max. In this work, it is demonstrated that further B1max reduction can be achieved by combining quadratic with higher-order polynomial-phase functions. RF pulses with a phase response up to tenth order were designed using the Shinnar-Le Roux transformation, yielding considerable increases in bandwidth and selectivity as compared to pure quadratic-phase pulses. These benefits are studied for a range of pulse specifications and demonstrated experimentally. For B1max = 20 microT and a pulse duration of 2.1 ms, it was possible to increase the bandwidth from 3.1 kHz for linear and 3.8 kHz for a quadratic to 9.9 kHz for a polynomial-phase pulse.

Reduced field-of-view MRI using outer volume suppression for spinal cord diffusion imaging

A spin-echo single-shot echo-planar imaging (SS-EPI) technique with a reduced field of view (FOV) in the phase-encoding direction is presented that simultaneously reduces susceptibility effects and motion artifacts in diffusion-weighted (DW) imaging (DWI) of the spinal cord at a high field strength (3T). To minimize aliasing, an outer volume suppression (OVS) sequence was implemented. Effective fat suppression was achieved with the use of a slice-selection gradient-reversal technique. The OVS was optimized by numerical simulations with respect to T(1) relaxation times and B(1) variations. The optimized sequence was evaluated in vitro and in vivo. In simulations the optimized OVS showed suppression to <0.25% and approximately 3% in an optimal and worst-case scenario, respectively. In vitro measurements showed a mean residual signal of <0.95% +/- 0.42 for all suppressed areas. In vivo acquisition with 0.9 x 1.05 mm(2) in-plane resolution resulted in artifact-free images. The short imaging time of this technique makes it promising for clinical studies.

Scale-up of anaerobic digestion of the biowaste fraction from domestic wastes

In the City of Karlsruhe/Germany anaerobic digestion of 7200 ta(-1) of separately collected biowaste has proven its feasibility at an organic loading rate (OLR) of up to 8.5 kg CODm(-3)d(-1). An extension of biowaste collection over the whole city area would increase the amount of biowaste to 12,000 ta(-1), leading to an OLR of the existing anaerobic reactor of up to 15 kg CODm(-3)d(-1). To test, whether the increased amount of biowaste could be stabilized in the existing plant, biowaste suspensions were digested in a laboratory reactor at a maximum OLR, that exceeded the future OLR of the full-scale plant. The laboratory reactor was started with effluent of the full-scale biowaste digester. Like in full-scale, biowaste suspension from the hydropulper was added in a fed-batch mode. The elimination of organic material (measured as COD, chemical oxygen demand) and the volumetric gas production were linearly increasing with the OLR from 4.3 to 19 kg CODm(-3)d(-1). Thus, safe operation of the full-scale plant at an OLR of 15 kg CODm(-3)d(-1) should be possible, leaving still some reserve capacity. To determine the metabolic reserves for fatty acid degradation during digestion at an OLR of 10 kg CODm(-3)d(-1), digester effluent was supplemented with either 40 mmoll(-1) acetate, propionate, i-butyrate or n-butyrate. Results of these batch assays indicated a rapid degradation of all fatty acids and fatty acid conversion rates, that would allow a stable anaerobic fermentation at 15 kg CODm(-3)d(-1)OLR. On the basis of the laboratory results the OLR of the full-scale methane reactor was increased to 15 kg CODm(-3)d(-1). After 7 months, results of full-scale digestion were still consistent with the previously obtained laboratory results.

Ripple formation through an interface instability from moving growth and erosion sources

The propagation of material interfaces is investigated under the action of a localized moving source which deposits or removes material. Among others the latter process applies to beam cutting techniques. We develop a Kuramoto-Sivashinsky-type model and find a new type of ripple forming mechanism. This theory offers a new explanation for the occurrence of striation patterns which often degrade the quality of cutting edges.

Circadian plasma leptin levels in patients with anorexia nervosa: relation to insulin and cortisol

In anorexia nervosa, underweight results from a loss of body mass due to a restricted energy intake. Circulating leptin levels have been shown to be low in the acute stage of the disorder. We studied diurnal secretion characteristics of leptin, insulin and cortisol in a study group of anorectic patients prior to refeeding, a second study group of anorectic patients after initiation of refeeding and study groups of healthy underweight and normal-weight controls. Spontaneous secretion of leptin, insulin and cortisol was measured by drawing blood samples every 2 h for 24 h. The temporal relationships between the diurnal secretion patterns of the three hormones were assessed by cross-correlation analysis in every study group. Plasma levels of leptin and cortisol were secreted with a specific circadian rhythmicity and displayed an intricate temporal relationship in anorectic patients. Semistarvation in the non-refed patients was associated with (1) exceedingly low plasma leptin levels, (2) a qualitative alteration in the circadian rhythm of leptin and cortisol levels and (3) an alteration in the temporal coupling between cortisol and leptin. In contrast, in the patients who had gained weight, leptin levels were higher; furthermore, the diurnal pattern of leptin and the temporal relationship between leptin and cortisol were similar to controls. Increments in insulin secretion preceded those of leptin by 4-6 h in both anorectic patients and in controls. Leptin levels increased 4 h prior to those of cortisol in controls and in refed patients, whereas in the non-refed patients cortisol increased prior to leptin. Thus, anorexia nervosa leads to pronounced, albeit reversible changes in the secretion dynamics of leptin and cortisol.

[Organ shortage in transplant centers--approaches to a solution from the economic viewpoint]

In the article the regulations of the German transplantation law, which came into force on 1 December 1997, are considered from an economic perspective. First, the essential regulations of the law are described and then analyzed with respect to economic aspects. The law regulates in particular the administration of the demand surplus for organs. This could be reduced by rationing the demand or by increasing the supply. Apart from the medical features economic attributes such as cost effectiveness are also applicable as criteria for rationing. In addition, the method of the quality-adjusted life-years (QALYs) is introduced and described on the basis of the results of a study about costs and benefits of liver transplantation. To increase the organ supply the authorities in Germany have so far established information campaigns and made appeals to the public. In contrast, an organ donation club the allocation of donors is made considering if and when the recipient declared his readiness to organ donation. In this way the willingness to donate his own organs could be sanctioned positively and an additional incentive for supply could be set.

Randomized controlled trial of anterior-chamber intraocular lenses in Nepal: long-term follow-up

Most of the estimated 20 million people who are blind with cataracts live in rural areas of developing countries, where expert surgical resources are scarce. We have studied the use of multiflex open-loop anterior-chamber intraocular lenses (ACIOL) in high-volume low-cost surgery. Between 1992 and 1995, a total of 2000 people attending Lahan Eye Hospital, Nepal, with bilateral cataracts reducing vision to < or = 6/36 were randomly allocated to receive intracapsular extraction (ICCE) with aphakic spectacles, or ICCE with an ACIOL. We re-examined the cohort (1305/2000, 65%) between November 1996 and April 1997 and report the findings in this article. There were 13 new cases of poor visual outcome (best corrected vision < 6/60) arising after one year: 9 in the ACIOL group and 4 in the control group; odds ratio 2.1 (95% confidence interval, 0.59-9.55). The causes of poor outcome were as follows: ACIOL group--retinal detachment (4 cases), cystoid macular oedema (2), epiretinal membrane (1), age-related macular degeneration (1), and late endophthalmitis (1); control group--retinal detachment (2 cases), late endophthalmitis (1), and primary open-angle glaucoma with age-related macular degeneration (1). In rural areas of developing countries, well-manufactured multiflex open-loop ACIOLs can be implanted safely by experienced ophthalmologists after routine ICCE, avoiding the disadvantages of aphakic spectacle correction.

Comorbidity of diabetes and eating disorders. Does diabetes control reflect disturbed eating behavior?

OBJECTIVE

This multicenter study was designed to explore the prevalence of clinical and subclinical eating disorders (EDs), the extent of intentional omission of insulin and oral antidiabetic agents, and its relationship to glycemic control in an inpatient and outpatient population of men and women with type 1 and type 2 diabetes.

RESEARCH DESIGN AND METHODS

Data have been collected from 12 diabetes medical centers in two German cities. In a questionnaire and interview-based study, a sample of male and female patients (n = 341 type 1, n = 322 type 2) was assessed for the following eating disorders: anorexia nervosa, bulimia nervosa, binge eating disorder, and eating disorder not otherwise specified. For lack of interview data of several patients meeting the screening criteria, prevalence ranges were calculated.

RESULTS

The overall prevalence range of current EDs was 5.9-8.0% (lifetime prevalence 10.3-14.0%). When patients were stratified according to type 1 and type 2 diabetes, there was no difference in prevalence of EDs. However, the distribution of the EDs was different in both types of diabetes, with a predominance of binge eating disorder in the type 2 diabetes sample. Type 1 (5.9%) and type 2 (2.2%) diabetic patients reported deliberate omission of hyperglycemic drugs (insulin or oral agents) in order to lose weight. Compared with control subjects, neither the presence of EDs nor insulin omission influenced diabetic control.

CONCLUSIONS

There seems to be no difference in prevalence rates of EDs in both types of diabetes; however, distribution of EDs is different. The findings suggest that neither EDs nor insulin omission are necessarily associated with poor control of glycemia. Binge eating disorder seems to precede type 2 diabetes in most patients and could be one of the causes of obesity that often precedes type 2 diabetes.