Response of the right ventricle to progressive pressure loading in pigs

Summary The purpose of this study was to determine the speed and duration of progressive pressure loading of the right ventricle to systemic pressure levels, which allows right ventricular adaptation without myocardial impairment at rest.In 8 pigs with an average weight of 22 kg progressive right ventricular pressure loading of different speeds and durations was induced with a newly developed constrictor. Pressures in the right atrium, right ventricle, and pulmonary artery as well as angiocardiographic volume parameters of the right ventricle were determined weekly over a period of 4 to 7 weeks. A fast progressive right ventricular pressure increase of 3.4 mm Hg/day during 3 weeks was associated with a 20–30% reduction of ejection fraction and a 100% increase of the end-systolic volume. Increase of end-diastolic pressure was 3 to 5 fold. A slow progressive pressure increase of 1.5 to 2.2 mm Hg/day to 100 mm Hg within 4 to 5 weeks was associated with an increase of the end-diastolic pressure to a level observed in systemic ventricles, while change of ejection fraction and end-systolic volume was minimal. The faster the increase of right ventricular pressure the flatter was the peak systolic pressure/end-systolic volume relationship.It is concluded that in contrast to sudden and fast progressive increase of afterload slow progressive increase of afterload to systemic levels does not impair right ventricular myocardial function.This study was supported by: Deutsche Forschungsgemeinschaft-grant HE 769/6-2     

Replacement of the aortic root by free implantation of a stentless aortic porcine bioprosthesis in a patient with aneurysm of the sinuses of Valsalva

In a patient with aneurysms of the sinuses of Valsalva a stentless porcine bioprosthesis was implanted with excellent hemodynamic and clinical short-term results. The implantation technique was similar to the technique used for the implantation of a composite graft. The postoperative study revealed a pressure gradient of 7 mmHg between the left ventricle and aorta and no regurgitation. Although the implantation of a porcine aortic root including a part of the ascending aorta without any artificial stenting material is feasible, one should be aware of the specific technical difficulties due to the increased rigidity of the fixated tissue. To our knowledge this is the first report of an implantation of a stentless aortic root porcine bioprosthesis for the treatment of aneurysms of the sinuses of Valsalva.     

Uptake of iodine-123-α-methyl tyrosine by gliomas and non-neoplastic brain lesions

Using single-photon emission tomography (SPET), the radiopharmaceuticall,-3-iodine-123--methyl tyrosine (IMT) has been applied to the imaging of amino acid transport into brain tumours. It was the aim of this study to investigate whether IMT SPET is capable of differentiating between high-grade gliomas, low-grade gliomas and non-neoplastic brain lesions. To this end, IMT uptake was determined in 53 patients using the triple-headed SPET camera MULTISPECT 3. Twenty-eight of these subjects suffered from high-grade gliomas (WHO grade III or IV), 12 from low-grade gliomas (WHO grade II), and 13 from non-neoplastic brain lesions, including lesions after effective therapy of a glioma (five cases), infarctions (four cases), inflammatory lesions (three cases) and traumatic haematoma (one case). IMT uptake was significantly higher in high-grade gliomas than in low-grade gliomas and non-neoplastic lesions. IMT uptake by low-grade gliomas was not significantly different from that by non-neoplastic lesions. Diagnostic sensitivity and specificity were 71% and 83% for differentiating high-grade from low-grade gliomas, 82% and 100% for distinguishing high-grade gliomas from non-neoplastic lesions, and 50% and 100% for discriminating low-grade gliomas from non-neoplastic lesions. Analogously to positron emission tomography with radioactively labelled amino acids and fluorine-18 deoxyglucose, IMT SPET may aid in differentiating high-grade gliomas from histologically benign brain tumours and non-neoplastic brain lesions; it is of only limited value in differentiating between non-neoplastic lesions and histologically benign brain tumours.     

Steady-state free precession projection MRI as a potential alternative to the conventional chest X-ray in pediatric patients with suspected pneumonia

Magnetic resonance imaging of the lung tissue is thought to be hardly possible due to physical limitations especially the low proton density, susceptibility, and motion artifacts. The objective of our study was to evaluate and refine a very fast MR technique at a low field strength which overcomes the limitations in MR lung imaging. Thirty-five investigations were performed in 30 pediatric patients with suspected pneumonia. The MR investigations were performed in coronal slice orientation without cardiac or respiratory triggering in a low-field MR system. An optimized true fast imaging with steady precession sequence was applied. The MR images and the corresponding conventional chest radiographs were evaluated. The examination time per slice was 1.6 s. No motion artifacts could be observed. The signal-to-noise ratio for pulmonary parenchyma ranged from 4.9 to 7.1. All pathological findings of the chest X-ray images were correctly identified by the MRI (κ=0.82–0.85). Effusions as well as small pneumonic infiltrates were more precisely detected by the MRI investigation (κ=0.82) as compared with X-ray. Low-field projection MRI is a promising alternative to pediatric chest X-ray. Due to its short examination time, it overcomes the physical limits of usual MRI methods and provides comparable diagnostic information. Electronic Publication     

Dose reduction in CT examination of children by an attenuation-based on-line modulation of tube current (CARE Dose)

In a controlled patient study we investigated the potential of attenuation-based on-line modulation of the tube current to reduce milliampere values (mAs) in CT examinations of children without loss of image quality. mAs can be reduced for non-circular patient cross sections without an increase in noise if tube current is reduced at those angular positions where the patient diameter and, consequently, attenuation are small. We investigated a technical approach with an attenuation-based on-line control for the tube current realised as a work-in-progress implementation. The CT projection data are analysed in real time to determine optimal mAs values for each projection angle. We evaluated mAs reduction for 100 spiral CT examinations with attenuation-based on-line modulation of the tube current in a group of children. Two radiologists evaluated image quality by visual interpretation in consensus. We compared the mAs values read from the CT scanner with preset mAs of a standard protocol. Four different scan regions were examined in spiral technique (neck, thorax, abdomen, thorax and abdomen). We found the mAs product to be reduced typically by 10-60% depending on patient geometry and anatomical regions. The mean reduction was 22.3% (neck 20%, thorax 23%, abdomen 23%, thorax and abdomen 22%). In general, no deterioration of image quality was observed. There was no correlation between the age and the mean mAs reduction in the different anatomical regions. By classifying the children respectively to their weight, there is a positive trend between increasing weight and mAs reduction. We conclude that mAs in spiral CT examinations of children can be reduced substantially by attenuation-based on-line modulation of the tube current without deterioration of image quality. Attenuation-based on-line modulation of tube current is efficient and practical for reducing dose exposure to children.     

Surgical treatment of symptomatic cerebral cavernous malformations in eloquent brain regions

Background

Despite the increased risk of hemorrhage and deteriorating neurological function of once-bled cerebral cavernous malformations (CM), the management of eloquently located CMs remains controversial.

Methods

All eloquently located CMs (n?=?45) surgically treated between 03/2006 and 04/2011 in our department were consecutively evaluated. Eloquence was characterized according to Spetzler and Martin's definition. The following locations were approached: brainstem, n?=?16; sensorimotor, n?=?8; visual pathway, n?=?7; cerebellum (deep nuclei and peduncles), n?=?7; basal ganglia, n?=?4, and language, n?=?3. Follow-up data was available for 41 patients (91 %) with a median interval of 14 months. Outcomes were evaluated according to the Glasgow outcome and the modified Rankin scale.

Results

Immediately after surgery, 47 % (n?=?21) had a new deficit. At follow-up, 80 % (n?=?36) recovered to at least preoperative status or were better than before surgery, 9 % (n?=?4) exhibited a slight, and 7 % (n?=?3) had a moderate neurological impairment. Only two cases (4 %) with a new permanent severe deficit were observed, both related to dorsal brainstem surgery. The outcome after the surgery of otherwise located brainstem CMs was as beneficial as that for non-brainstem CMs. Patients with initially poor neurological performance fared worse than oligosymptomatic patients.

Conclusions

Despite the high postoperative transient morbidity, the majority improved profoundly during follow-ups. Compared with natural history, surgical treatment should be considered for all eloquent symptomatic CMs. Dorsal brainstem location and poor preoperative neurological status are associated with an increased postoperative morbidity.

     

Pelvic pain in urogynecology. Part II: treatment options in patients with lower urinary tract symptoms

Therapeutic options for chronic pelvic pain in women offer only a limited symptom relief. Especially in the patient with lower urinary tract symptoms (LUTS), where overlap of pain, storage and voiding symptoms is common, data on the efficacy of treatment of pain are limited. We conducted a literature review to detect articles which pertained to female patients with LUTS and pelvic pain and we included articles which evaluated the efficacy of the treatment of pelvic pain. Forty-one articles were detected, which included nerve stimulation (sacral and pudendal), intravesical instillations and injections, oral pharmacological treatments, periurethral injections as well as physical and manual therapy as treatment options. Only five controlled trials were found, which did not show superiority of the active treatment versus placebo. Although some treatment options show promising results in the treatment of pelvic pain in patients with LUTS, more randomised controlled trials are needed to confirm these results.