Distinguishing recurrent intra-axial metastatic tumor from radiation necrosis following gamma knife radiosurgery using dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging

BACKGROUND AND PURPOSE

MR image-guided gamma knife radiosurgery is often used to treat intra-axial metastatic neoplasms. Following treatment, it is often difficult to determine whether a progressively enhancing lesion is due to metastatic tumor recurrence or radiation necrosis. The purpose of our study was to determine whether relative cerebral blood volume (rCBV), relative peak height (rPH), and percentage of signal-intensity recovery (PSR) derived from dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging can distinguish recurrent metastatic tumor from radiation necrosis.

MATERIALS AND METHODS

Twenty-seven patients with systemic cancer underwent gamma knife radiosurgery for metastatic lesions of the brain and subsequently developed enlarging regions of enhancement within the radiation field. Subsequent surgical resection or clinicoradiologic follow-up established a diagnosis of recurrent metastatic tumor or radiation necrosis. Perfusion MR imaging datasets were retrospectively reprocessed, and regions of interest were drawn around the entire contrast-enhancing region. The resulting T2* signal-intensity time curves produced rCBV, rPH, and PSR values for each examination. A Welch t test was used to compare imaging values between groups.

RESULTS

The mean, minimum, and maximum PSR values were significantly lower (P < .01) in cases of recurrent metastatic tumor. The mean and maximum rCBV and rPH values were significantly higher (P < .02) in the recurrent metastatic tumor group.

CONCLUSIONS

The findings of our study suggest that perfusion MR imaging may be used to differentiate recurrent intra-axial metastatic tumor from gamma knife-induced radiation necrosis.

HIV voluntary counselling and testing in Nakuru, Kenya: findings from a community survey

OBJECTIVES

HIV voluntary counselling and testing (VCT) is important for prevention, detection and treatment of HIV infection. A study was conducted to determine the extent of utilization of VCT, and to study the attitudes and preferences of the community regarding VCT.

METHODS

A total of 301 adults, aged 18-49 years, residing in Nakuru, Kenya were randomly selected using a two-stage sampling process. A self-administered questionnaire delivered during home visits was used to collect data over a 4-week period.

RESULTS

The majority of study participants (184 of 287; 64.1%) had never been tested for HIV; 77 (26.8%) had received VCT, and 26 (9.1%) had received HIV testing without counselling. A total of 219 (78.2%) of the 280 responding participants expressed readiness to have VCT. The majority of participants (216 of 296; 73%) preferred VCT, while 46 (15.5%) preferred testing without counselling. The majority (227; 76.7%) preferred couple testing and dedicated clinics and private doctors' offices as testing facilities. The choice of a nearby facility was ranked above the provision of anonymity by most participants (162 of 298; 54.4%; vice versa for 136 of 298; 45.6%).

CONCLUSIONS

With HIV/AIDS continuing to be a major public health concern in Kenya, the issues surrounding acceptance and use of VCT need to be addressed. Enhancing community awareness of the benefits of early HIV diagnosis, providing couple-based VCT as an integral part of VCT and increasing access to VCT testing sites may enhance utilization of VCT.

Analysis of metabolic indices in regions of abnormal perfusion in patients with high-grade glioma

BACKGROUND AND PURPOSE

MR spectroscopic imaging (MRSI) and dynamic susceptibility-contrast MR imaging (DSC-MR imaging) are functional in vivo techniques for assessing tumor metabolism and vasculature characteristics. Because tumor hypoxia is influenced by tortuous, degraded, swollen, and angiogenic tumor vasculature, regions of abnormal perfusion parameters should coexist with changes in lactate and creatine metabolite levels.

MATERIALS AND METHODS

DSC-MR imaging and lactate-edited MRSI were performed on 38 treatment-naive patients with high-grade gliomas (17 grade III, 21 grade IV) before surgical diagnosis. Regions of abnormal perfusion were determined from peak height and percent recovery maps for each voxel within the spectroscopic imaging volume. Choline, creatine, and lactate levels within voxels experiencing only abnormal peak height (aPH), only abnormal recovery (aRec), and both abnormal peak height and recovery (aPH+aRec) were determined and compared to the surrounding T2 hyperintensity (T2h) and normal-appearing white matter.

RESULTS

There were decreasing trends in volume from aPH to aRec to aPH+aRec regions for both grade III and grade IV gliomas. Grade IV gliomas exhibited significantly elevated choline in all abnormal perfusion regions, with reduced creatine and increased lactate in the aRec region relative to the surrounding T2h. Grade III gliomas showed trends toward increased creatine within the aPH region and reduced levels within the aRec region.

CONCLUSION

Depressed creatine and elevated lactate levels confirmed the lack of oxygenation within regions of compromised vascular integrity. Identification of regions with leaky or dense vasculature and metabolic markers of hypoxia and cellular proliferation could be useful in determining the more aggressive part of the tumor for targeting, monitoring, and assessing effects of treatment.

Assessment of vasculature of meningiomas and the effects of embolization with intra-arterial MR perfusion imaging: a feasibility study

BACKGROUND AND PURPOSE

Embolization of meningiomas has emerged as a preoperative adjuvant therapy that has proved effective in mitigating blood loss during surgical resection. Arterial supply to these tumors is typically identified by diffuse areas of parenchymal staining after selective x-ray angiograms. We investigate the benefits that selective injection of MR contrast may have in identifying vascular territories and determining the effects of embolization therapy.

MATERIALS AND METHODS

Selective intra-arterial (IA) injection of dilute MR contrast media was used to assess the vascular distribution territories of meningeal tumors before and after embolization therapy. Regions of the tumor that experienced loss of signal intensity after localized contrast injections into the external and common carotid as well as vertebral arteries were used to quantify the specific vessel's volume of distribution. Assessments were made before and after embolization to reveal changes in the vascular supply of the tumor. MR findings were compared with radiographic evaluation of tumor vascular supply on the basis of conventional x-ray angiography.

RESULTS

MR proved to be an excellent means to assess tissue fed by selected arteries and clearly demonstrated the treated and untreated portions of the neoplasm after therapy. In some instances, MR revealed postembolization residual enhancement of the tumor that was difficult to appreciate on x-ray angiograms. Very low contrast dose was necessary, which made repeated assessment during therapy practical.

CONCLUSION

MR perfusion imaging with selective IA injection of dilute contrast can reveal the distribution territory of vessels. Changes in tumor vasculature could be detected after embolization, which reveal the volumetric fraction of the tumor affected by the therapy.

Differentiation of glioblastoma multiforme and single brain metastasis by peak height and percentage of signal intensity recovery derived from dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging

BACKGROUND AND PURPOSE

Glioblastoma multiforme (GBM) and single brain metastasis (MET) are the 2 most common malignant brain tumors that can appear similar on anatomic imaging but require vastly different treatment strategy. The purpose of our study was to determine whether the peak height and the percentage of signal intensity recovery derived from dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion MR imaging could differentiate GBM and MET.

MATERIALS AND METHODS

Forty-three patients with histopathologic diagnosis of GBM (n=27) or MET (n=16) underwent DSC perfusion MR imaging in addition to anatomic MR imaging before surgery. Regions of interest were drawn around the nonenhancing peritumoral T2 lesion (PTL) and the contrast-enhancing lesion (CEL). T2* signal intensity-time curves acquired during the first pass of gadolinium contrast material were converted to the changes in relaxation rate to yield T2* relaxivity (Delta R2*) curve. The peak height of maximal signal intensity drop and the percentage of signal intensity recovery at the end of first pass were measured for each voxel in the PTL and CEL regions of the tumor.

RESULTS

The average peak height for the PTL was significantly higher (P=.04) in GBM than in MET. The average percentage of signal intensity recovery was significantly reduced in PTL (78.4% versus 82.8%; P=.02) and in CEL (62.5% versus 80.9%, P<.01) regions of MET compared with those regions in the GBM group.

CONCLUSIONS

The findings of our study show that the peak height and the percentage of signal intensity recovery derived from the Delta R2* curve of DSC perfusion MR imaging can differentiate GBM and MET.

Progress in understanding autoimmune exocrinopathy using the non-obese diabetic mouse: an update

Sjögren's Syndrome (SS) is a chronic autoimmune disease characterized by histological and functional alterations of salivary and lacrimal glands that result in a severe dryness of the mouth and the eyes. The etiology of SS has remained undefined despite investigators' significant efforts to identify the mechanisms of initiation. Based on histopathology, several animal models are available--such as MRL/lpr, NZW/NZB, NFS/sld, graft vs. host, transgenic mouse expressing viral surface antigen, and the non-obese diabetic (NOD) mouse--for investigation of the etiology of SS. Biochemical and immunological similarities between human SS and autoimmune exocrinopathy (AEC) in the NOD mouse, including the loss of secretory function, establish the NOD mouse as an appropriate model to unravel the underlying pathophysiology of SS. Recently, several NOD congenic partner strains have been developed to investigate the roles of genetic intervals, cytokines, and autoantibodies in the disease pathogenesis. Studies on NOD-scid suggest that the pathogenesis of SS occurs in two phases: an asymptomatic phase, in which epithelial cells of exocrine tissues undergo dedifferentiation accompanied by elevated apoptosis; and a second phase in which autoaggression is mounted against target organ autoantigens, resulting in the activation of T- and B-cells, and the generation of autoantibodies. The presence of autoantibodies on the cell-surface signaling receptor, the muscarinic(3) receptor, in both SS patients and the NOD mice correlates with the hallmark clinical symptom of secretory dysfunction. Additionally, the NOD mouse model provides an important example of how both Th1 and Th2 cytokines, as well as non-immune genetic loci, are involved in the maintenance of and progression to the overt disease state. Ultimately, analysis of these data provides insight into potentially novel therapeutic interventions.

Overexpression of the osteopontin correlates with the aggressiveness of endometrial cancer

16048

Background: To test the hypothesis that expression of osteopontin (OPN), an integrin-binding glycoprotein, can independently predict the potential aggressiveness of endometrial cancer. Methods: The status of OPN expression in benign and malignant endometrial cancer cell lines and tissues was analyzed by real time PCR, Western blot, and immunohistochemistry. Nonparametric Spearman's correlation coefficient method was used to assess the statistical significance of the correlation between clinicopathologic characteristics of tumor and OPN expression. Results: An increased expression of OPN was observed in the endometrial cancer compared to normal endometrial tissue samples. When the level of OPN in normal tissue was set at 1, its level in benign endometrial hyperplasia was slightly increased at 1.2, whereas the OPN level in the highly malignant endometrial carcinoma tissue was greatly increased by nearly 3–5 folds. Amongst the 160 cases examined immunohistochemically, of the 43 grade 1 endometrial carcinomas, 31 were unstained and 12 stained weakly positive (+). For the 41 grade 3 or serous type endometrial carcinomas analyzed, 25 (60%) stained strongly positive (+++), 8 (19%) stained moderately positive (++) and 4 (9%) stained weakly positive (+). These results showed that the level of OPN expressed between grade 1 and grade 3 or more was significantly different (Spearman's correlation coefficient method, p = 0.001). However, Kaplan-Meier survival analysis showed that the increased level of OPN expression was not significantly associated with reduced survival time of the patients. Conclusion: The results suggest that the increased OPN level may be involved in the malignant transformation of endometrial adenocarcinoma cells.

No significant financial relationships to disclose.

Effect of zoledronic acid on bone loss by letrozole

11077

Background: The aromatase inhibitors cause bone loss by estrogen depletion. Zoledronic acid (ZA) can prevent bone mineral density (BMD) loss associated with the use of aromatase inhibitors. Accordingly interest has arisen in measuring surrogate markers of bone resorption to monitor the response of treatment of BMD loss in place of radiologic assessment. This study was designed to determine whether ZA would prevent bone loss that is known to occur with letrozole and identified surrogate markers of bone resorption in an animal model. Methods: In ovariectomized or sham-operated rat, we administrated ZA and letrozole to 5 different groups including: a sham operation control group (OC), a group in which an ovariectomy was performed followed by saline administration (OS), an ovariectomy with ZA treatment group (OZ), an ovariectomy with letrozole treatment group (OL) and an; ovariectomy with ZA and letrozole combined treatment group (OZL). The levels of serum osteocalcin, serum bone alkaline phosphatase (BALP), serum calcium and urine N-telopeptide (NTX) and BMD were estimated and compared at the same periods for each group. The distinct microscopic findings of proximal tibia at week sixteen were also compared. Results: Significantly intense increment of BDM in the OZ group and the OZL group and lower increment in the OL group were valued in correlation to the OS group, 31.3%, 35.0%, 10.5% and 13.0% respectively. Serum osteocalcin levels and urine calcium levels were close to each group. Serum calcium levels and BALP levels were relatively lowering in the OZ group and the OZL group than other group. Meaningfully lower levels of urine NTX were measured in the OZ group and the OZL group, 6.6% and 16.5% respectively. In the OL group levels of urine NTX were rise of 55.9%. Less cancellous bone loss and increase bone trabeculae were noted in the microscopic findings of tibia. Conclusions: The combination treatment with ZA and letrozole are effective in the inhibition of bone resorption and in the maintenance of BMD. Measurement of serum osteocalcin, urine NTX, and BMD, levels are recommended as surrogate markers for determining the response for the treatment of bone loss.

No significant financial relationships to disclose.

Multi-segment foot motion analysis on hallux valgus patients

In this study, a multi-segment foot motion analysis on hallux valgus patients were performed using the 9-segment foot model and then compared with the results from normal subjects. Results showed that there were no significant differences in hindfoot motions between normal subjects and HV patients. However, noted in HV patients were hyperexternal rotation in the talocrural joint, an excessive eversion of the subtalar joint during early stance and lack of dynamic motion in hallux MP and medial MP joints especially during terminal stance. In spite of limitation in this study due to the small number of HV patients, the current multi-segment foot model would be feasible to diagnose and treat patients with various foot diseases, combined with further studies in the future.

Sjögren's syndrome-like disease of C57BL/6.NOD-Aec1 Aec2 mice: gender differences in keratoconjunctivitis sicca defined by a cross-over in the chromosome 3 Aec1 locus

Sjögren's syndrome (SjS) is a systemic autoimmune disease in which an immunological attack primarily against the salivary and lacrimal glands results in loss of acinar cell tissue and function leading to stomatitis sicca and keratoconjunctivitis sicca. In recent years, the NOD mouse has become an accepted model of SjS, exhibiting a spontaneously developing disease that strongly mimics the human condition. Two genetic regions, one on chromosome 1 (designated Aec2) and the second on chromosome 3 (designated Aec1) of NOD mice, have been shown to be necessary and sufficient to recapitulate SjS-like disease in non-susceptible C57BL/6 mice. Here we describe a newly derived strain, C57BL/6.NOD-Aec1R1Aec2, in which a recombination in Aec1 has resulted in reducing this genetic region to less than 20 cM from 48.5 cM. Profiling of this recombinant inbred strain has revealed that male mice maintain a full SjS-like disease, whereas female mice exhibit stomatitis sicca in the absence of detectable keratoconjunctivitis sicca. These data suggest SjS-like disease in the NOD mouse shows gender-specific regulation determined by autosomal genes.

Overexpression of the osteopontin correlates with the aggressiveness of endometrial cancer

5038

Background: To test the hypothesis that expression of osteopontin (OPN), an integrin-binding glycoprotein, can independently predict the potential aggressiveness of endometrial cancer. We studied OPN expression in endometrial cell carcinomas and correlated OPN expression levels with clinicopathologic tumor features. Methods: The status of OPN expression in benign and malignant endometrial cancer cell lines and tissues was analyzed by Western blot and immunohistochemistry. Nonparametric Spearman’s correlation coefficient method was used to assess the statistical significance of the correlation between clinicopathologic characteristics of tumor and OPN expression. Results: An increased expression of OPN was observed in the endometrial cancer compared to normal endometrial tissue samples. When the level of OPN in normal tissue was set at 1, its level in benign endometrial hyperplasia was slightly increased at 1.2, whereas the OPN level in the highly malignant endometrial carcinoma tissue was greatly increased by nearly 3- 5 folds. Amongst the 70 cases examined immunocytochemically, of the 23 grade 1 endometrial carcinomas, 6 were unstained and 12 stained weakly positive (+). For the 20 grade 3 or serous type endometrial carcinomas analyzed, 8 (40%) stained strongly positive (+++), 8 (40%) stained moderately positive (++) and 1 stained weakly positive (+). These results showed that the level of OPN expressed between grade 1 and grde 3 or more was significantly different (Spearman’s correlation coefficient method, p = 0.001). Kaplan-Meier survival analysis showed that the increased level of OPN expression was significantly associated with reduced survival time of the patients. Conclusions: The results suggest that the increased OPN level may be involved in the malignant transformation of endometrial adenocarcinoma cells and OPN expression level is an important determinant for patient survival.

No significant financial relationships to disclose.

Quantitative measurement of blood-brain barrier permeability using perfusion-CT in extra-axial brain tumors

Non-invasive assessment of vascular permeability is of main importance in the diagnosis, treatment and follow-up of intracranial tumors. Perfusion-CT is one of the imaging options available, which affords quantitative assessment of cerebral blood volume and blood-brain barrier permeability. Herein we report two cases of extra-axial tumors studied with perfusion-CT. Comparison with perfusion-MRI was available in one case. High permeability values, as measured by perfusion-CT, reflected the absence of blood-brain barrier in these extra-axial tumors.

Comparison of microvascular permeability measurements, K(trans), determined with conventional steady-state T1-weighted and first-pass T2*-weighted MR imaging methods in gliomas and meningiomas

BACKGROUND AND PURPOSE

The widely accepted MR method for quantitating brain tumor microvascular permeability, K(trans), is the steady-state T1-weighted gradient-echo method (ssT1). Recently the first-pass T2*-weighted (fpT2*) method has been used to derive both relative cerebral blood volume (rCBV) and K(trans). We hypothesized that K(trans) derived from the ssT1 and the fpT2* methods will correlate differently in gliomas and meningiomas because of the unique differences in morphologic and functional status of each tumor vascular network.

METHODS

Before surgery, 27 patients with newly diagnosed gliomas (WHO grade I-IV; n = 20) or meningiomas (n = 7) underwent conventional anatomic MR imaging and 12 dynamic ssT1 acquisitions followed by 60 dynamic fpT2* images before and after gadopentate dimeglumine administration. The 3 hemodynamic variables-fpT2* rCBV, fpT2* K(trans), and ssT1 K(trans)-were calculated in anatomically identical locations and correlated with glioma grade. The fpT2* K(trans) values were compared with ssT1 K(trans) for gliomas and meningiomas.

RESULTS

All 3 hemodynamic variables displayed distinct distributions among grades 2, 3, and 4 gliomas by using the Kruskal-Wallis test. Only K(trans) values, and not rCBV, could differentiate between grade 4 and lower-grade gliomas by using the Wilcoxon rank sum test. The fpT2* K(trans) was highly predictive of ssT1 K(trans) for gliomas, with an estimated regression coefficient of 0.49 (P < .001). For meningiomas, however, fpT2* K(trans) values correlated poorly with ssT1 K(trans) values (r = 0.26; P = .74).

CONCLUSION

Compared with rCBV, K(trans) values derived from either ssT1 or fpT2* were more predictive of glioma grade. The fpT2* K(trans) was highly correlated with ssT1 K(trans) in gliomas but not in meningiomas.