High-fidelity simulation of lung isolation with double-lumen endotracheal tubes and bronchial blockers in anesthesiology resident training

OBJECTIVES

Demonstrate the feasibility of using the AirSim Bronchi airway simulator to teach residents how to manage lung isolation with double-lumen endotracheal tubes and bronchial blockers and evaluate their performance with a detailed checklist.

DESIGN

Prospective observational study.

SETTING

University anesthesiology residency training program.

PARTICIPANTS

Anesthesiology residents taking a cardiothoracic anesthesiology rotation.

INTERVENTIONS

Residents were instructed in 7 tasks using the AirSim Bronchi: The use of the fiberoptic bronchoscope, methods for placing left and right double-lumen endotracheal tubes and 3 bronchial blockers (Univent, Arndt, and Cohen), and application of continuous positive airway pressure (CPAP) to the unventilated lung. Two to 3 weeks later, checklists and a detailed scoring system were used to assess performance. Residents rated the curriculum and their own confidence in performing the tasks using a 5-point Likert scale.

MEASUREMENTS AND MAIN RESULTS

Thirteen residents completed the curriculum. Their median Likert scale ratings of the curriculum based on a questionnaire with 6 items ranged from 4 to 5 of 5. Resident confidence scores for each lung isolation technique improved after the simulation training, with the median gain ranging from 0.5 to 1.5 Likert levels depending on the task. The largest improvement occurred with the bronchial blockers (p<0.05). The median performance score for the 7 tasks combined was 88% of the maximum possible points.

CONCLUSIONS

The authors used the AirSim Bronchi simulator in a novel simulation curriculum to teach lung-isolation techniques to anesthesiology residents and evaluated performance using a detailed checklist scoring system. This curriculum is a promising educational tool.

The effect of the pressure-volume curve for positive end-expiratory pressure titration on clinical outcomes in acute respiratory distress syndrome: a systematic review

PURPOSE

Methods to optimize positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS) remain controversial despite decades of research. The pressure-volume curve (PVC), a graphical ventilator relationship, has been proposed for prescription of PEEP in ARDS. Whether the use of PVC's improves survival remains unclear.

METHODS

In this systematic review, we assessed randomized controlled trials (RCTs) comparing PVC-guided treatment with conventional PEEP management on survival in ARDS based on the search of the National Library of Medicine from January 1, 1960, to January 1, 2010, and the Cochrane Central Register of Controlled Trials. Three RCTs were identified with a total of 185 patients, 97 with PVC-guided treatment and 88 with conventional PEEP management.

RESULTS

The PVC-guided PEEP was associated with an increased probability of 28-day or hospital survival (odds ratio [OR] 2.7, 95% confidence interval [CI] 1.5, 4.9) using a random-effects model without significant heterogeneity (I (2) test: P = .75). The PVC-guided ventilator support was associated with reduced cumulative risk of mortality (-0.24 (95% CI -0.38, -0.11). The PVC-managed patients received greater PEEP (standardized mean difference [SMD] 5.7 cm H2O, 95% CI 2.4, 9.0) and lower plateau pressures (SMD -1.2 cm H2O, 95% CI -2.2, -0.2), albeit with greater hypercapnia with increased arterial pCO2 (SMD 8 mm Hg, 95% CI 2, 14). Weight-adjusted tidal volumes were significantly lower in PVC-guided than conventional ventilator management (SMD 2.6 mL/kg, 95% CI -3.3, -2.0).

CONCLUSION

This analysis supports an association that ventilator management guided by the PVC for PEEP management may augment survival in ARDS. Nonetheless, only 3 randomized trials have addressed the question, and the total number of patients remains low. Further outcomes studies appear required for the validation of this methodology.

A multicenter evaluation of a compact, sterile, single-use pressure transducer for central venous catheter placement

BACKGROUND

Inadvertent arterial placement of a large-bore catheter during attempted placement of a central venous catheter (CVC) occurs at a rate of 0.1% to 1.0% and may result in hemorrhage, pseudoaneurysm, stroke, or death. Ultrasound guidance or observation of color and pulsatility of blood are not reliable methods for avoiding this serious complication. Measurement of pressure in the needle or short plastic catheter before insertion of the guidewire has been shown to be highly reliable; however, traditional pressure measurement methodology is cumbersome. Recently a compact, sterile, single-use pressure transducer with an integrated digital display has become available. In this study, we evaluated the performance of this new device (Compass® Vascular Access).

METHODS

In this prospective, observational study at 4 academic medical centers 298 CVCs were placed. Pressure was measured using the Compass transducer before and after guidewire insertion. Other details of the procedure were at the discretion of the clinician. Data describing the CVC placement and any complications were collected.

RESULTS

Trainees placed 279 of 298 CVCs. Ultrasound guidance was used for 286 of 298 CVCs. Seven of the CVC placements occurred in the intensive care unit, with the balance occurring in the operating room. Ten of the CVCs were placed in a subclavian vein, with the balance being internal jugular vein. Two hundred seventy-four of 298 CVCs were placed on the right side. Venous pressure measured before and after guidewire insertion was 7.2 ± 4.3 (SD) and 6.5 ± 4.3 (SD) mm Hg respectively (P = 0.03). The satisfaction score recorded by the physician performing the procedure was 8.0 ± 2.1 (SD; visual analog scale 1-10, 10 being most satisfying). There were 5 inadvertent arterial punctures (1.7%). Ultrasound guidance was used in all 5 cases of arterial puncture. All of the arterial punctures were recognized before guidewire insertion by measurement of arterial pressure with the Compass transducer. No guidewires or CVC catheters were placed in arteries.

CONCLUSION

The Compass pressure transducer for CVC placement performed as intended in 298 cases from 4 academic medical centers. There were 5 inadvertent arterial punctures despite the use of ultrasound guidance, all of which were correctly identified by pressure measurement using the Compass. The device was easily used by trainees, and users expressed a positive level of satisfaction.

Visualization of lenticulostriate arteries by flow-sensitive black-blood MR angiography on a 1.5 T MRI system: a comparative study between subjects with and without stroke

BACKGROUND AND PURPOSE

The branches of the LSA are the main causative arteries for lacunar infarction, though the vascular changes are largely unknown. Herein, we examined the correlation of LSA imaging findings in patients with lacunar infarction compared with controls by using FSBB-MRA.

MATERIALS AND METHODS

Fifteen patients (9 men, 6 women; mean age, 73 years) with infarction at the basal ganglia and/or its vicinity were prospectively enrolled, and 12 aged-matched control subjects (6 men, 6 women; mean age, 68 years) were examined by using FSBB-MRA on a 1.5T MR imaging system. Total number and length of visualized LSA branches were compared by a 2-tailed 2-sample t test. Stepwise multiple regression analyses were performed, including hypertension, hyperlipidemia, smoking history, and diabetes mellitus after evaluation of their colinearity. P<.05 after correction for multiple comparisons was considered significant.

RESULTS

Patients with stroke had significantly fewer LSA branches (average, 6.3; 95% CI, 5.4-7.1) than controls (8.7; 95% CI, 7.8-9.5) (P=.0003). The total LSA lengths were 117 mm (95% CI, 96-138 mm) for patients with stroke and 162 mm (95% CI, 133-91 mm) for control subjects (P=.01). In stepwise multiple regression analysis, only the LSA branch numbers were significantly related to infarction (P=.0003), while only hypertension was significantly related to total LSA length (P=.0085).

CONCLUSIONS

Using FSBB-MRA to visualize LSA branches, we found a significant reduction in the numbers of LSA branches in patients with stroke, and hypertension was inversely related to total LSA length. FSBB is a promising method to investigate the LSA by using 1.5T MR imaging.

Concanamycin A, a vacuolar type H(+)-ATPase inhibitor, induces cell death in activated CD8(+) CTL

Concanamycin A (CMA) and concanamycin B (CMB) are specific inhibitors of vacuolar type H(+)-ATPase (V-ATPase). In our previous studies, intraperitoneal injection of CMB was shown to suppress the increase in CD8(+) CTL population, but not to affect CD4(+) and B220(+) populations, in mice immunized with allogeneic tumors. To clarify the molecular basis of the selective decrease in the CD8(+) CTL population by CMB, we have performed a series of in vitro experiments with use of CMA. Cell viability of the CD8(+) population prepared from the immunized mice was preferentially decreased by CMA treatment. Moreover, in the CD8(+) CTL clone, CMA induced a marked DNA fragmentation and nuclear condensation characteristic of apoptosis. Anti-CD3 or phorbol ester accelerated the CMA-induced reduction in cell viability of the CD8(+) CTL clone, but not CD4(+) T cell clones. However, this rapid cell death was not accompanied by DNA fragmentation and nuclear condensation. Perforin and granzyme B were unlikely to be involved in such cell death. Thus, our data suggest that V-ATPase activity is essential for survival of CD8(+) CTL especially when activated.

Reduced-distortion diffusion MRI of the craniovertebral junction

BACKGROUND AND PURPOSE

CVJ lesion suffers from a high sensitivity to susceptibility and distortion artifacts, which sometimes makes diffusion image difficult to interpret. Our purpose was to evaluate the potential for diffusion MR imaging using RS-EPI compared with SS-EPI in the assessment of the CVJ.

MATERIALS AND METHODS

RS-EPI and SS-EPI DTI images were acquired from 10 healthy volunteers using 3T MRI with a 32-channel head coil. For both sequences, the following parameters were used: 1-mm(2) in-plane resolution; 3-mm section thickness; TR = 5200 ms; 1 acquisition at b = 0 and 12 different encoding directions at b = 1000 seconds/mm(2). The RS-EPI sequence scan time was 9.44 minutes (1 average). The SS-EPI sequence was 9.37 minutes (8 averages). Diffusion tensor calculation and image analysis were performed using DTIStudio software. Diffusion trace images and color-coded fiber orientation maps were evaluated by 2 independent readers for distortion and delineation of fine structure using a semiquantitative scale in selected landmark locations. The absolute distances between the temporal base and the cerebellar contour between the T2-weighted images and the diffusion trace images obtained with RS-EPI and SS-EPI were also compared.

RESULTS

The contours of the temporal lobe and cerebellum were better delineated and distortion artifacts were clearly reduced with the RS-EPI sequence. More fine structures were also visible in the brain stem and cerebellum with the RS-EPI sequence. The amount of distortion was significantly reduced with RS-EPI compared with SS-EPI (P < .01).

CONCLUSIONS

The RS-EPI DTI sequence was less prone to geometric distortion than the SS-EPI sequence and allowed a better delineation of CVJ internal structure. Although the acquisition time is still relatively long, the RS-EPI appears as a promising approach to perform DTI studies in CVJ lesions, such as brain stem ischemia, neurodegenerative diseases, brain and skull base tumors, or inflammation.

Lactation persistency as a component trait of the selection index and increase in reliability by using single nucleotide polymorphism in net merit defined as the first five lactation milk yields and herd life

We first sought to clarify the effects of discounted rate, survival rate, and lactation persistency as a component trait of the selection index on net merit, defined as the first five lactation milks and herd life (HL) weighted by 1 and 0.389 (currently used in Japan), respectively, in units of genetic standard deviation. Survival rate increased the relative economic importance of later lactation traits and the first five lactation milk yields during the first 120 months from the start of the breeding scheme. In contrast, reliabilities of the estimated breeding value (EBV) in later lactation traits are lower than those of earlier lactation traits. We then sought to clarify the effects of applying single nucleotide polymorphism (SNP) on net merit to improve the reliability of EBV of later lactation traits to maximize their increased economic importance due to increase in survival rate. Net merit, selection accuracy, and HL increased by adding lactation persistency to the selection index whose component traits were only milk yields. Lactation persistency of the second and (especially) third parities contributed to increasing HL while maintaining the first five lactation milk yields compared with the selection index whose only component traits were milk yields. A selection index comprising the first three lactation milk yields and persistency accounted for 99.4% of net merit derived from a selection index whose components were identical to those for net merit. We consider that the selection index comprising the first three lactation milk yields and persistency is a practical method for increasing lifetime milk yield in the absence of data regarding HL. Applying SNP to the second- and third-lactation traits and HL increased net merit and HL by maximizing the increased economic importance of later lactation traits, reducing the effect of first-lactation milk yield on HL (genetic correlation (rG) = -0.006), and by augmenting the effects of the second- and third-lactation milk yields on HL (rG = 0.118 and 0.257, respectively).

Evaluation of CT angiography for visualisation of the lenticulostriate artery: difference between normotensive and hypertensive patients

OBJECTIVE

High-resolution CT angiography (CTA) is currently available using multidetector row CT (MDCT); however, its use for small artery visualisation has been limited. To evaluate its capability, we investigated CTA visualisation for difference in number of the lenticulostriate artery (LSA) branches between normotensive and hypertensive patients, because hypertension is a major cause of LSA damage.

METHODS

This was a retrospective study evaluating cerebrovascular CTA at our hospital conducted from February 2008 to June 2009 under approval of the institutional review board. 117 patients (39 males and 78 females, 19-88 years old) were included. CTA was conducted using a 64 channel MDCT. Total numbers of LSA branches were examined for differences by age with regression analysis and the presence or absence of hypertension and/or aneurysm using two-sample t-tests. A p-value <0.016 was considered statistically significant after correction for multiple comparisons. A multiple variable analysis of three factors was also conducted.

RESULTS

The average number of LSA branches was 3.6 [95% confidence interval (CI) 3.0-4.1] and 4.4 (95% CI 4.1-4.7), respectively, for a patient with and without history of hypertension, and the difference was statistically significant (p=0.013). The difference was approximately one branch in the multiple variable analysis. No significant correlation was observed for age and no significant difference was observed for the presence or absence of aneurysms.

CONCLUSIONS

Contrast-enhanced CTA can visualise significant differences in the number of LSA branches among patients with and without hypertension. Advances in knowledge Current high-resolution CTA can visualise LSA well, which enables finding a difference in the LSA between normotensive subjects and hypertensive patients.

Utility of FDG PET/CT in IgG4-related systemic disease

IgG4-related systemic disease (IgG4-RSD) is an emerging clinical entity about which much remains to be elucidated, in terms of its aetiology, pathogenesis, diagnosis, treatment and outcome. Autoimmune pancreatitis (AIP) and Mikulicz disease (MD) are the two major, well-studied constituents of IgG4-RSD. AIP and MD have common characteristics of forming tumour-mimicking lesions that consist of lymphoplasmacytic infiltrates and fibrosclerosis with numerous immunoglobulin G4 (IgG4)-positive plasma cells, as well as various multi-organ manifestations of IgG4-RSD. 2-[(18)F]-fluoro-2-deoxy-d-glucose positron-emission tomography/ computed tomography (FDG PET/CT) enables the acquisition of whole-body images and provides functional information about disease activity; as such it has a valuable role in staging extent of disease, guiding biopsy, and monitoring response to treatment. However, FDG PET/CT is likely to be only one component of the management strategy, and clinical, laboratory, imaging and histological findings are crucial in the overall diagnosis of the condition. At present FDG PET/CT does not have a well-established role in the assessment of patients with IgG4-RSD and future prospective studies are required to define the cost-effectiveness and clinical impact in this patient group more accurately.

Whole-heart coronary MR angiography under a single breath-hold: a comparative study with respiratory-gated acquisition using a multi-element phased-array coil

AIM

To compare visualization using whole-heart coronary magnetic resonance angiography (CMRA) acquired during a single breath-hold (BH) with that using conventional respiratory-gated (RG) CMRA.

MATERIALS AND METHODS

The CMRAs of 14 healthy subjects under either BH or RG conditions were studied using a 1.5 T system equipped with a whole-body phased-array coil and 16-channel receivers. The BH examination was accelerated using parallel imaging (PI) by factors of 2.5 and 2 in the phase and section directions, respectively. For the RG examination, a PI factor of 2 was used only in the phase direction. The visualization quality of 15 coronary segments using each condition was evaluated with a five-point scale (0-4). Differences between two conditions were compared at segments with an average score greater than 2 in RG-CMRA.

RESULTS

The average examination time for BH and RG acquisition scans was 34 s and 11 min 31 s, respectively. Ten segments (segments 1-3, 5-9, 11, and 13) had average scores higher than 2 in RG-CMRA. Of these, BH-CMRA had significantly lower scores than RG-CMRA at six segments (segments 1, 5-8, and 11) after correction for multiple comparisons (p<0.005). However, in BH-CMRA, proximal segments (segments 1-2, 5-7, and 11) showed average scores over 2, indicating marginally acceptable image quality.

CONCLUSION

Compared with the relatively limited degree of image degradation with RG-CMRA, the present data suggest that BH-CMRA would be useful for screening and as an adjunct to RG-CMRA that is occasionally incomplete.

Uptake of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid in metastatic adrenal tumour from hepatocellular carcinoma

We present the case of a metastatic adrenal tumour from hepatocellular carcinoma (HCC) showing the uptake of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) on MRI. To our knowledge, this is the first case of metastatic HCC in which Gd-EOB-DTPA uptake was shown on MRI and this finding facilitated the accurate pre-operative diagnosis of a metastatic adrenal tumour.

The efficiency of genome-wide selection for genetic improvement of net merit

Four methods of selection for net merit comprising 2 correlated traits were compared in this study: 1) EBV-only index (I₁), which consists of the EBV of both traits (i.e., traditional 2-trait BLUP selection); 2) GEBV-only index (I₂), which comprises the genomic EBV (GEBV) of both traits; 3) GEBV-assisted index (I₃), which combines both the EBV and the GEBV of both traits; and 4) GBV-assisted index (I₄), which combines both the EBV and the true genomic breeding value (GBV) of both traits. Comparisons of these indices were based on 3 evaluation criteria [selection accuracy, genetic response (ΔH), and relative efficiency] under 64 scenarios that arise from combining 2 levels of genetic correlation (r(G)), 2 ratios of genetic variances between traits, 2 ratios of the genomic variance to total genetic variances for trait 1, 4 accuracies of EBV, and 2 proportions of r(G) explained by the GBV. Both selection accuracy and genetic responses of the indices I₁, I₃, and I₄ increased as the accuracy of EBV increased, but the efficiency of the indices I₃ and I₄ relative to I₁ decreased as the accuracy of EBV increased. The relative efficiency of both I₃ and I₄ was generally greater when the accuracy of EBV was 0.6 than when it was 0.9, suggesting that the genomic markers are most useful to assist selection when the accuracy of EBV is low. The GBV-assisted index I₄ was superior to the GEBV-assisted I₃ in all 64 cases examined, indicating the importance of improving the accuracy of prediction of genomic breeding values. Other parameters being identical, increasing the genetic variance of a high heritability trait would increase the genetic response of the genomic indices (I₂, I₃, and I₄). The genetic responses to I₂, I₃, and I(4) was greater when the genetic correlation between traits was positive (r(G) = 0.5) than when it was negative (r(G) = -0.5). The results of this study indicate that the effectiveness of the GEBV-assisted index I₃ is affected by heritability of and genetic correlation between traits, the ratio of genetic variances between traits, the genomic-genetic variance ratio of each index trait, the proportion of genetic correlation accounted for by the genomic markers, and the accuracy of predictions of both EBV and GBV. However, most of these affecting factors are genetic characteristics of a population that is beyond the control of the breeders. The key factor subject to manipulation is to maximize both the proportion of the genetic variance explained by GEBV and the accuracy of both GEBV and EBV. The developed procedures provide means to investigate the efficiency of various genomic indices for any given combination of the genetic factors studied.

Staging of uterine cervical cancer with MRI: guidelines of the European Society of Urogenital Radiology

OBJECTIVE

To design clear guidelines for the staging and follow-up of patients with uterine cervical cancer, and to provide the radiologist with a framework for use in multidisciplinary conferences.

METHODS

Guidelines for uterine cervical cancer staging and follow-up were defined by the female imaging subcommittee of the ESUR (European Society of Urogenital Radiology) based on the expert consensus of imaging protocols of 11 leading institutions and a critical review of the literature.

RESULTS

The results indicated that high field Magnetic Resonance Imaging (MRI) should include at least two T2-weighted sequences in sagittal, axial oblique or coronal oblique orientation (short and long axis of the uterine cervix) of the pelvic content. Axial T1-weighted sequence is useful to detect suspicious pelvic and abdominal lymph nodes, and images from symphysis to the left renal vein are required. The intravenous administration of Gadolinium-chelates is optional but is often required for small lesions (<2 cm) and for follow-up after treatment. Diffusion-weighted sequences are optional but are recommended to help evaluate lymph nodes and to detect a residual lesion after chemoradiotherapy.

CONCLUSIONS

Expert consensus and literature review lead to an optimized MRI protocol to stage uterine cervical cancer. MRI is the imaging modality of choice for preoperative staging and follow-up in patients with uterine cervical cancer.

Changes in apparent diffusion coefficients in the normal uterus during different phases of the menstrual cycle

This study investigated the apparent diffusion coefficients (ADCs) of the uterine zonal structures (myometrium, endometrium and junctional zone) among reproductive women, and their changes during the menstrual cycle. Magnetic resonance (MR) images of seven healthy females (aged 24-31 years) were obtained during the periovulatory, luteal and menstrual phases. Diffusion-weighted imaging (DWI) was performed with a single-shot echo-planar imaging (EPI) sequence in the midsagittal plane of the uterus using three b-values (b = 0, 500 or 1000 s mm(-2)). The ADC values of the three uterine zonal structures were measured on an ADC map by placing two regions of interest (ROI) on the corresponding zonal structures. The average changes of ADC values (intra-individual ADC value variation) over three menstrual phases were 0.41 x 10(-3) mm(2) s(-1) (range, 0.08-0.91) for myometrium, 0.55 x 10(-3) mm(2) s(-1) (0.35-0.84) for endometrium, and 0.40 x 10(-3) mm(2) s(-1) (0.18-0.59) for the junctional zone. The ADC values for myometrium and endometrium were lower in the menstrual phase, although there was some overlap of individual values. Interindividual variation in ADC value for a given zone or phase ranged from 0.48 x 10(-3) mm(2) s(-1) to 0.85 x 10(-3) mm(2) s(-1). Intermeasurement variation between the two ROIs ranged from 0 to 0.48 x 10(-3) mm(2) s(-1) per measurement. The magnitude of these variations was comparable to reported differences between malignant and non-malignant tissues. These preliminary results, from a small number of subjects, suggest that the menstrual cycle and individual variation in pre-menopausal women should be considered when interpreting the ADC values of uterine structures.

[Pure red cell aplasia after resection for thymoma with myasthenia gravis]

A 73 year-old woman was diagnosed as thymoma with myasthenia gravis (MG) [ocular type] 18 years ago, but she rejected surgical treatment. The remission of myasthenia gravis has been obtained by treatment of medication. This time, to avoid myasthenic crisis at the time of orthopedic surgery, she underwent surgical treatment for thymoma: extended-thymectomy, resection of the left brachiocephalic vein and reconstraction using ringed polytetrafluoroethylene (ePTFE) graft. Pathologic diagnosis was Masaoka stage III thymoma and World Health Organization (WHO) type B2 + B3. After orthopedic surgery, irradiation was performed for mediastinum. During this period from the resection of thymoma to irradiation, she developed gradually progressive anemia, and as a result of bone marrow examination, she was diagnosed as pure red cell aplasia (PRCA). PRCA has improved with immunosuppressive treatment. One year have passed with no recurrence of thymoma and PRCA.

Theoretical efficiency of multiple-trait quantitative trait loci-assisted selection

The effectiveness of five selection methods for genetic improvement of net merit comprising trait 1 of low heritability (h(2) = 0.1) and trait 2 of high heritability (h(2) = 0.4) was examined: (i) two-trait quantitative trait loci (QTL)-assisted selection; (ii) partial QTL-assisted selection based on trait 1; (iii) partial QTL-assisted selection based on trait 2; (iv) QTL-only selection; and (v) conventional selection index without QTL information. These selection methods were compared under 72 scenarios with different combinations of the relative economic weights, the genetic correlations between traits, the ratio of QTL variance to total genetic variance of the trait, and the ratio of genetic variances between traits. The results suggest that the detection of QTL for multiple-trait QTL-assisted selection is more important when the index traits are negatively correlated than when they are positively correlated. In contrast to literature reports that single-trait marker-assisted selection (MAS) is the most efficient for low heritability traits, this study found that the identified QTL of the low heritability trait contributed negligibly to total response in net merit. This is because multiple-trait QTL-assisted selection is designed to maximize total net merit rather than the genetic response of the individual index trait as in the case of single-trait MAS. Therefore, it is not economical to identify the QTL of the low heritability traits for the improvement of total net merit. The efficient, cost-effective selection strategy is to identify the QTL of the moderate or high heritability traits of the QTL-assisted selection index to facilitate total economic returns. Detection of the QTL of the low h(2) traits for the QTL-assisted index selection is justified when the low h(2) traits have high negative genetic correlation with the other index traits and/or when both economic weights and genetic variances of the low h(2) traits are larger as compared to the other index traits of higher h(2). This study deals with theoretical efficiency of QTL-assisted selection, but the same principle applies to SNP-based genomic selection when the proportion of the genetic variance 'explained by the identified QTLs' in this study is replaced by 'explained by SNPs'.

[Lung metastasis of thymic carcinoma twelve years after complete resection of primary disease]

We report a 67-year-old woman who developed lung metastasis 12 years after resection of the mediastinal tumor which was diagnosed as B3-thymoma. Combined resection of bilateral lungs and left innominate vein was performed due to tumorimvasion. 12 years later, she was diagnosed as having primary lung adenocarcinoma with bronchoscopic examination and cytology. Postoperative histological and immunohistochemical examination showed that the lung nodule was a lymphoepithelioma-like carcinoma of the thymus with strong immunoreactivity for CD5 and bcl-2. Reexamination by immunohistochemical staining for CD5 and bcl-2 revealed that the disease diagnosed as thymoma 12 years ago was also thymic carcinoma Accurate differential diagnosis between B3-thymoma and thymic carcinoma is essential for choosing appropriate postoperative treatment.

Normal pituitary stalk: high-resolution MR imaging at 3T

BACKGROUND AND PURPOSE

Knowing the normal imaging appearance of the pituitary stalk is important for the diagnosis of pituitary infundibular lesions, and more accurate assessment of the stalk may be possible at 3T than at 1.5T. Our purpose was to evaluate the normal pituitary stalk by use of high-resolution MR imaging at 3T.

MATERIALS AND METHODS

Sagittal MPRAGE images and high-resolution oblique-axial T2-weighted images of the pituitary stalk were acquired in 29 healthy volunteers (16 men and 13 women; mean age, 28 years; age range, 21-43 years) at 3T. The diameter and length of the pituitary stalk and the depth of the infundibular recess were measured. Signal intensity of the stalk was visually evaluated on T2-weighted images.

RESULTS

The AP and transverse diameters of the pituitary stalk were 2.32 +/- 0.39 mm and 2.16 +/- 0.37 mm at the pituitary insertion, respectively, and 3.25 +/- 0.43 mm and 3.35 +/- 0.44 mm at the level of the optic chiasm. No significant differences were observed between the AP and transverse diameters at each level. The length of the stalk was 5.91 +/- 1.24 mm, and the depth of the infundibular recess was 4.69 +/- 0.87 mm. The stalk showed central hyperintensity with a peripheral rim of isointensity in 20 subjects (69%) and homogeneous isointensity in 9 subjects (31%).

CONCLUSIONS

The data of the current study can serve as standard measurements of the normal pituitary stalk. The central hyperintensity and peripheral rim may represent the infundibular stem and pars tuberalis, respectively.

[Mediastinal goiter extending to tracheal bifurcation; report of a case]

The patient was a 64-year-old female with an abnormal shadow on chest X-ray examination. Chest computed tomography (CT) revealed mediastinal goiter. Concerning the laboratory data, the FT3 and FT4 values were within the normal ranges. However, the thyroid stimulating hormone (TSH) level was slightly decreased. The tumor involved the paratracheal region along its posterior surface, extending an area below the bifurcation of the trachea. Therefore, median sternotomy was chosen to remove the tumor. Pathologically, no nuclear atypia was noted in the follicular epithelium, suggesting adenomatous goiter. The patient was discharged without complications. There has been no relapse during the 9-month postoperative follow-up.