Revised PROPELLER for T2-weighted imaging of the prostate at 3 Tesla: impact on lesion detection and PI-RADS classification

Purpose

To evaluate revised PROPELLER (RevPROP) for T2-weighted imaging (T2WI) of the prostate as a substitute for turbo spin echo (TSE).

Materials and methods

Three-Tesla MR images of 50 patients with 55 cancer-suspicious lesions were prospectively evaluated. Findings were correlated with histopathology after MRI-guided biopsy. T2 RevPROP, T2 TSE, diffusion-weighted imaging, dynamic contrast enhancement, and MR-spectroscopy were acquired. RevPROP was compared to TSE concerning PI-RADS scores, lesion size, lesion signal-intensity, lesion contrast, artefacts, and image quality.

Results

There were 41 carcinomas in 55 cancer-suspicious lesions. RevPROP detected 41 of 41 carcinomas (100%) and 54 of 55 lesions (98.2%). TSE detected 39 of 41 carcinomas (95.1%) and 51 of 55 lesions (92.7%). RevPROP showed fewer artefacts and higher image quality (each p?<?0.001). No differences were observed between single and overall PI-RADS scores based on RevPROP or TSE (p?=?0.106 and p?=?0.107). Lesion size was not different (p?=?0.105). T2-signal intensity of lesions was higher and T2-contrast of lesions was lower on RevPROP (each p?<?0.001).

Conclusion

For prostate cancer detection RevPROP is superior to TSE with respect to motion robustness, image quality and detection rates of lesions. Therefore, RevPROP might be used as a substitute for T2WI.

Key points

? Revised PROPELLER can be used as a substitute for T2-weighted prostate imaging.? Revised PROPELLER detected more carcinomas and more suspicious lesions than TSE.? Revised PROPELLER showed fewer artefacts and better image quality compared to TSE.? There were no significant differences in PI-RADS scores between revised PROPELLER and TSE.? The lower T2-contrast of revised PROPELLER did not impair its diagnostic quality.

     

A New Preoperative Planning Technique Can Reduce Radiation Exposure During the Performance of Medial Opening-Wedge High Tibial Osteotomy

Background

Medial opening-wedge high tibial osteotomy (HTO) is one of the most common and effective HTO techniques, in which the proximal tibia is cut medially, leaving an intact lateral hinge of bone that can be opened to a variable amount for the desired correction, but the technical complications of lateral cortex fracture and intra-articular fracture are well described. The lateral bone hinge for medial opening-wedge HTO is crucial. If the hinge is too small, the tibia can fracture and become unstable, requiring further fixation. If the hinge is too large, the osteotomy can propagate into the joint as an intra-articular fracture when opening the osteotomy.

Purpose

We propose a new technique that utilizes digital preoperative templating to improve the accuracy of the cut. Preoperative digital templating may allow the surgeon to reproducibly obtain a lateral bone hinge of 10 mm, while also reducing radiation exposure relative to the traditional fluoroscopically assisted technique.

Methods

Ten cadaver extremities from five cadavers were matched into pairs and randomized into two groups: those with and without preoperative templating. The templating protocol measures the distance between two points on the medial and lateral cortices, and 20 mm is subtracted to determine the depth of the saw cut (10 mm for the hinge and another 10 mm because the proximal tibia is oval in shape). The control method was done by making the cut using fluoroscopy with tactile feedback. Postoperative computed tomography scans were obtained of all legs to measure the width of the lateral bone hinge. Intraoperative fluoroscopy used during both techniques and the numbers of fluoroscopy shots were recorded.

Results

We found neither the treatment group with preoperative planning nor the control group with the conventional technique had bone hinge widths that were different from the ideal 10 mm. The average hinge widths for the treatment and control groups were 11.2 and 11.5 mm, respectively. However, the treatment group was exposed to significantly less intraoperative fluoroscopy during the osteotomy cut. The average total number of fluoroscopy shots was 2.2 in the treatment group versus 6.3 for the control group.

Conclusions

This new preoperative planning technique achieves similar accuracy of the lateral bone hinge when compared to current methods but exposes the patient, surgeon, and staff to significantly less intraoperative radiation.

     

Biomechanical analysis of stair ambulation in lower limb amputees

Lower extremity amputees have to cope with many activities in everyday life that are substantially more difficult than walking on level ground, and such demands require a high degree of functionality from their prosthetic components. The present study is a biomechanical evaluation (kinematics, kinetics and EMG) of stair ascent and descent in a group of eight transtibial amputees (mean (standard deviation): age 51(14) years, height 176(7)cm, mass 88(19)kg); a group of 12 transfemoral amputees (age 37(8) years, height 182(7)cm, mass 83(7)kg) fitted with the electronically controlled C-LEG knee joint system; and a group of 12 able bodied persons (age 30(10) years, height 174(12)cm, mass 69(12)kg). During stair descent the transfemoral amputees presented a strong reduction of the prosthetic ankle moments (0.11Nm/kg) compared to transtibial amputees (0.93Nm/kg) and control subjects (1.26Nm/kg). Loading of the prosthetic knee joint in the transfemoral amputees more closely resembles the loading seen in the control population when compared to transtibial amputees (mean maximum flexion moment: controls 1.31Nm/kg, transfemoral amputees 1.00Nm/kg, transtibial amputees 0.50Nm/kg). Overload of the contralateral limb is more prominent in the transfemoral amputee than in the transtibial amputee. During stair ascent, the transtibial amputee presents a significant reduction of the knee flexion moment compared to the controls (mean maximum flexion moment: transtibial amputees 0.28Nm/kg, controls 1.31Nm/kg). These differences correlate with a change in the muscle activity of the knee extensor and hamstring muscles. The results also show adaptations in motor strategies during stair negotiation, for those with the partial loss of a lower limb due to the functional limits of current prosthetic components. The present data may contribute to a further enhancement of the efficiency of prosthetic feet and knee joints.     

Deferoxamine enhances phagocytic function of human polymorphonuclear leukocytes

Inhibition of the iron-mediated generation of toxic oxygen species by polymorphonuclear leukocytes (PMN) might prevent oxidative damage and thus enhance phagocytic function of PMN. To investigate this point, we studied the effect of the specific iron chelator, deferoxamine, on the antibacterial function of PMN. PMN were incubated for 20 hr with various concentrations of deferoxamine at 37 degrees C in medium containing 0.54 microM endogenous iron. The cells were then washed, and the phagocytic cell function was assessed. The results were compared with those for control PMN preincubated for 20 hr without deferoxamine, and those of nonincubated PMN. Compared with that of control PMN, the uptake of radiolabeled Staphylococcus aureus by PMN treated with 1 microM-1 mM deferoxamine was, on average, 10%-20% higher. This effect was not observed when iron-saturated deferoxamine (DFO) was used. Bacterial uptake was similarly increased in nonpreincubated PMN or PMN preincubated for 20 hr at 4 degrees C instead of 37 degrees C. The intracellular killing capacity of both deferoxamine-treated and control PMN exceeded 90%. PMN incubated for 20 hr at 37 degrees C with DFO not only phagocytosed more bacteria than control cells, but were also capable of killing the greater number of bacteria ingested. This increased activity of deferoxamine-treated PMN was accompanied by enhanced generation of chemiluminescence and production of superoxide during phagocytosis of S. aureus. These findings indicate that deferoxamine may enhance the antibacterial activity of PMN by protecting the cells against damage by iron-mediated generation of toxic oxygen metabolites in resting PMN.     

Percutaneous transtracheal ventilation in a canine shock model with an open thorax

This study evaluates the effectiveness of percutaneous transtracheal ventilation (PTV) in a canine shock model. Five mongrel dogs (25 to 35 kg), splenectomized two weeks prior to study, were anesthetized (pentobarbital, 22 mg/kg) and bled to and sustained at a mean arterial pressure (MAP) of 20 mm Hg for 60 minutes. Ringer's lactate was infused and the descending thoracic aorta was cross-clamped. Simultaneously, PTV was begun with 60% O2 through the cricothyroid membrane. Hemodynamic measurements and arterial blood gases were obtained at 0, 5, 15, and 30 minutes following the initiation of PTV. Orotracheal ventilation was then instituted in place of PTV and continued for 30 minutes, and measurements were repeated. Auto-transfusion was also begun at this time. During PTV, PO2 and PCO2 were adequate in all dogs at each interval. We conclude that PTV provides effective oxygenation and ventilation in dogs subjected to profound shock, thoractomy, and thoracic aortic cross-clamp.     

Evaluation of myocardial metabolism with microdialysis after protection with cold blood- or cold crystalloid cardioplegia. A porcine model

OBJECTIVES: There has been a considerable change in the patient population referred for cardiac surgery in the last decade. More complex and marginal patients require optimized myocardial protection. An insufficient cardioplegic procedure results in anaerobic metabolism during cardiac arrest with subsequent lactate accumulation. Increased lactate level is regarded as a predictor for low cardiac output syndrome. In an acute porcine model we examined two standard cardioplegic methods. Myocardial microdialysis was used to investigate the metabolism during cardioplegic arrest and in the reperfusion period. METHODS: Twelve domestic pigs were randomly chosen to receive either cold blood-or cold crystalloid cardioplegia. After midline sternotomy two microdialysis probes were implanted in two different regions of the heart. Cardiopulmonary bypass was initiated, aorta was clamped, and antegrade cardioplegia was delivered. These conditions were maintained for 90 min. Subsequent to myocardial reperfusion the animals were observed for 180 min. Microdialysis and plasma markers to characterize myocardial metabolism, and plasma markers for myocardial failure and necrosis were obtained every 30 min. RESULTS: Lactate concentrations were significantly increased in the cold crystalloid cardioplegia group compared to the cold blood cardioplegia group, in tissue dialysate (p < 0.001) as well as in serum (p = 0.018). Pyruvate concentrations in the dialysate were significantly increased in the cold crystalloid cardioplegia group compared to the cold blood cardioplegia group (p = 0.008). There were no significant differences in dialysate concentrations of glycerol. Plasma markers for myocardial failure (Brain Natriuretic Peptide) and for myocardial necrosis (Cardiac Troponin T) showed no differences between the groups. CONCLUSION: The results indicate that cold blood cardioplegia offers superior protection of the heart, in terms of more rapid normalization of myocardial metabolism. The microdialysis technique seems to have a high sensitivity and ability to detect even minor metabolic changes. This enhances the possibility of designing a myocardial protection, which might lower morbidity and mortality risk.     

Parathyroid mitogenic activity in plasma from patients with familial multiple endocrine neoplasia type 1

Hyperplasia of the parathyroid glands is a central feature of familial multiple endocrine neoplasia type 1. We used cultured bovine parathyroid cells to test for mitogenic activity in plasma from patients with this disorder. Normal plasma stimulated [3H]thymidine incorporation, on the average, to the same extent as it was stimulated in a plasma-free control culture. This contrasted with the results of the tests with plasma from patients with familial multiple endocrine neoplasia type 1, in which parathyroid mitogenic activity increased 2400 percent over the control value (P less than 0.001). Plasma from these patients also stimulated the proliferation of bovine parathyroid cells in culture, whereas plasma from normal subjects inhibited it. Parathyroid mitogenic activity in plasma from the patients with familial multiple endocrine neoplasia type 1 was greater than that in plasma from patients with various other disorders, including sporadic primary hyperparathyroidism (with adenoma, hyperplasia, or cancer of the parathyroid), sporadic primary hypergastrinemia, sporadic pituitary tumor, familial hypocalciuric hypercalcemia, and multiple endocrine neoplasia type 2 (P less than 0.05). Parathyroid mitogenic activity in the plasma of patients with familial multiple endocrine neoplasia type 1 persisted for up to four years after total parathyroidectomy. The plasma also had far more mitogenic activity in cultures of parathyroid cells than did optimal concentrations of known growth factors or of any parathyroid secretagogue. This mitogenic activity had an apparent molecular weight of 50,000 to 55,000. We conclude that primary hyperparathyroidism in familial multiple endocrine neoplasia type 1 may have a humoral cause.     

Standardisierte Kontrastmittelsonographie (CEUS) in der klinischen Akut- und Notfallmedizin sowie Intensivmedizin (CEUS-Akut)

Die Anaesthesiologie -     

Assessment of the Melody valve in the mitral position in young children by echocardiography

Objectives

Mitral valve replacement (MVR) in young children is limited by the lack of small prostheses. Our institution began performing MVR with modified, surgically placed, stented jugular vein grafts (Melody valve) in 2010. We sought to describe key echocardiographic features for pre- and postoperative assessment of this novel form of MVR.