Contrast enhancement of small hepatocellular carcinoma: usefulness of three successive early image acquisitions during multiphase dynamic MR imaging

OBJECTIVE

The purpose of this study was to document the usefulness of early triphasic image acquisition during gadolinium-enhanced multiphase dynamic MR imaging for the detection of contrast enhancement in small hepatocellular carcinoma.

SUBJECTS AND METHODS

Dynamic MR imaging was performed in 332 patients at 1.5 T using a T1-weighted fast low-angle shot sequence (TR range/TE, 113-130/4.1; flip angle, 80 degrees). With the start of bolus injection of gadolinium dimeglumine (0.1 mmol/kg) into the antecubital vein, three sets of contrast-enhanced images of the entire liver were obtained serially at 10, 35, and 60 sec. Contrast enhancement of the tumor detected on each phase was evaluated in conjunction with the unenhanced T1-weighted images for 52 patients with small hepatocellular carcinomas up to 2 cm in diameter (n = 79).

RESULTS

The first phase images depicted a larger number (n = 57) of contrast enhancement of small hepatocellular carcinoma tumors than the second (n = 44) or third phase images (n = 14). Twenty-six lesions were enhanced only during the first phase, and nine, during the second phase. The detection rate of contrast enhancement in the combination of first and second phases was the same as the overall detection rate for all three phases (70/79, 89%) and significantly higher than those of each phase.

CONCLUSION

Early multiple image acquisition is helpful for the assessment of small hepatocellular carcinoma and is enabled by the high detection rate of contrast enhancement regardless of individual variations in the timing of enhancement.

Reanalysis of the effects of air pollution on daily mortality in Seoul, Korea: A case-crossover design

We used the case-crossover design to identify any increase in mortality in Seoul, Korea, when there were higher levels of ambient air pollution on case-days than would be expected solely as a result of chance. This empirical study showed that either unidirectional retrospective (selecting only control days prior to death) or prospective (selecting only control days after death) control sampling could cause risk estimates to be confounded by seasonal waves as well as time trends in air pollution levels. In bidirectional control sampling in which exposures at death were compared with exposures both before and after death, the estimated mortality was resistant to confounding by time patterns of air pollution. Using a bidirectional control sampling approach, the results from a conditional logistic regression model controlling for weather conditions showed that the nonaccidental mortality associated with a 50-ppb increment over a 3-day moving average of SO(2) concentrations, including the concurrent day and preceding 2 days, was 1.023 [95% confidence interval (CI), 1.016-1.084]. The relative risk of death was 1.023 (CI, 0.999-1.048) per 50 ppb for 1-hr maximum O(3) and 1.010 (CI, 0.988-1.032) per 100 microg/m(3 )or total suspended particulates. In conclusion, the findings of this study were 2-fold: given the consistency of the observed association between SO(2) and daily mortality across different analysis methods, the association reported here indicates that air pollution is a probable contributor to premature death; and bidirectional control sampling is needed in a case-crossover design applied to air pollution epidemiologic studies to control confounding by seasonal patterns of air pollution as well as time trends.

Respiratory function as measured by peak expiratory flow rate and PM10: six communities study

This Six Communities Study conducted at six communities in southwestern North Carolina investigates the respiratory health status of residents whose households are located near an incinerator. This diary study makes it possible to estimate the daily variation of pulmonary function measured as peak expiratory flow rate (PEFR) related to 24-h mean PM10 levels, which were observed at each monitoring station placed in the six study communities, as a surrogate exposure measure of outdoor air pollution. Observations of PEFR among participants in each community were analyzed to determine how they varied according to the degree of exposure to ambient pollutants as well as to other cofactors including, sex, age, respiratory hypersensitivity, hours spent outdoors within the area of the selected community, and surrogate measures for indoor air pollution exposure (vacuum use and experience of air irritants at work). The findings revealed that respiratory hypersensitivity status is a predictor of declining PEFR. PM10 concentrations measured in each study area did not seem to be related to the variations of respiratory health as measured by PEFR. This study did not show any difference in respiratory health between subjects of an incinerator community and those of its comparison community. Even though this community-based study with free-living subjects shows negative findings on the relationship between respiratory health and PM10, it is worth noting that these findings must be interpreted cautiously because exposure estimation based on monitoring of ambient air likely results in misclassification of true exposure levels.

Focal eosinophilic infiltration of the liver: a mimick of hepatic metastasis

We present three cases of focal eosinophilic infiltration in the liver that mimicked hepatic malignancy on computed tomography during hepatic arteriography (CTHA) and computed tomography during arterial portography (CTAP). In all patients, focal eosinophilic liver infiltration appeared as a solitary nodule or as two nodules without hepatosplenomegaly and showed homogeneous hyperattenuation on CTHA and hypoattenuation on CTAP.

Pericardial tamponade and massive pleural effusion complicating orthotopic heart transplantation

Pericardial and pleural effusions occur commonly after open cardiac procedures. However, the combination of tamponade and massive pleural effusion is not often observed. We present a case of such a patient who received an orthotopic heart transplant in a setting of previously diagnosed systemic sarcoidosis. Treatment ultimately required the creation of a pericardial window and chemical pleurodesis.

Isolation, characterization, and stability of positional isomers of mono-PEGylated salmon calcitonins

PURPOSE

To separate and characterize the different positional isomers of mono-PEGylated salmon calcitonins (mono-PEG-sCTs) and to evaluate the effects of the PEGylation site on the stability of different mono-PEG-sCTs in rat kidney homogenate.

METHODS

Mono-PEG-sCTs were prepared using succinimidyl carbonate monomethoxy polyethylene glycol (5,000 Da) and separated by gel-filtration HPLC followed by reversed-phase HPLC. To characterize PEGylated sCTs, matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) and reversed-phase HPLC of the trypsin digested samples were performed. Mono-PEG-sCTs and sCT in rat kidney homogenates were measured by column-switching reversed-phase HPLC with on-line detection of the radioiodinated samples using a flow-through radioisotope detector.

RESULTS

Three different mono-PEGylated sCTs were separated by reversed-phase gradient HPLC. From the MALDI-TOF MS analysis, the average molecular weight of mono-PEG-sCTs was confirmed as around 8650 Da. The presence of PEG moiety in the mono-PEG-sCTs was also manifested by the fact that the distance between two adjacent mass spectum lines was 44 Da which corresponds to PEG monomer unit. Tryptic digestion analysis demonstrated that these mono-PEG-sCTs are 3 positional isomers of N-terminus, Lys18- and Lys11-residue modified mono-PEGylated sCTs. The degradation half-life of these 3 positional isomers in rat kidney homogenates significantly increased in order of the N-terminus (125.5 min), Lys11- (157.3 min), and Lys18 residue modified mono-PEGylated sCT (281.5 min) over the native sCT (4.8 min).

CONCLUSION

Three positional isomers of mono-PEGylated sCTs were purified and characterized. Of these, the resistance to proteolytic degradation was highest for the Lys18-residue modified mono-PEG-sCT. These studies demonstrate that the in vivo stability of PEGylated sCTs is highly dependent on the site of PEG molecule attachment.

T2-weighted fast spin-echo MR findings of adenocarcinoma of the uterine cervix: comparison with squamous cell carcinoma

The purpose of this study was to investigate the differences in MR findings of adenocarcinoma (AC) and squamous cell carcinoma (SCC) of the uterine cervix and to compare MR findings with pathologic findings. MR images of 17 patients with pathologically proven AC, using a fast spin-echo (FSE) T2-weighted image (T2WI) with pelvic phased-array coil on a 1.5-T unit, were retrospectively evaluated. After measurement of the signal intensity (SI) ratios of the region of interest between tumors and gluteus maximus muscle, we compared the ratios of AC with those of 16 patients with SCC. AC showed relatively high SI on FSE T2WI with multiseptated lesions in four cases and hydrometrocolpos in three cases. The mean SI ratio was 3.82 +/- 1.68 in AC and 2.35 +/- 0.42 in SCC (p < 0.0001, t-test). Multiple tumorous glands with cytoplasmic and intraglandular mucin or serous fluid were pathologically found in AC, but SCC revealed the compact cellularity of stratified squamous tumor cells. The cervical AC showed higher SI than SCC on FSE T2WI with occasional multiseptated lesions and hydrometrocolpos. If the SI ratio of the tumor was more than 3.0, AC could be diagnosed with a sensitivity of 68.8% and a specificity of 100%.

Preparation and characterization of polyethylene-glycol-modified salmon calcitonins

The conjugation of salmon calcitonin (sCT) by covalent linkage of polyethylene glycol (PEG) was attempted to overcome several disadvantages of sCT as a therapeutic drug, namely its rapid clearance from blood circulation and enzymatic degradation. The polymer employed was succinimidyl carbonate monomethoxypolyethylene glycol (12 kDa). Superose HR size-exclusion chromatography was applied to separate the PEGylated sCTs (mono-PEG-sCT and di-PEG-sCT) from the unmodified sCT. The PEGylation of sCT was verified by an electrophoresis gel stained with iodine and by MALDI-TOF mass spectrometry. The molecular weights of mono-PEG-sCT and di-PEG-sCT were determined to be 16,094 and 29,077 Da, respectively. PEGylated sCTs showed a substantially improved stability in rat liver homogenates as compared to the intact sCT, indicating that PEG molecules protected sCT from various degrading enzymes. These PEGylated sCTs exhibited similar biological activity to the intact sCT by adenosine cyclic 3',5'-phosphate (cAMP) assay. In clearance studies in the rat, PEGylated sCTs had significantly longer circulating half-lives than the intact sCT (11.2 min for mono-PEG-sCT and 54.0 min for di-PEG-sCT versus 4.7 min for intact sCT).

Tsix, a gene antisense to Xist at the X-inactivation centre

In mammals, dosage compensation is achieved by X inactivation and is regulated in cis by the X-inactivation centre (Xic) and Xist. The Xic controls X-chromosome counting, choice of X to inactivate and initiation of silencing. Xic action culminates in a change in Xist RNA property from a scarce, unstable RNA to highly expressed Xist RNA that coats the future inactive X. Deleting a 65-kb region downstream of Xist results in constitutive Xist expression and X inactivation, implying the presence of a cis-regulatory element. In this region, we now report the discovery of a gene antisense to Xist. Tsix is a 40-kb RNA originating 15 kb downstream of Xist and transcribed across the Xist locus. Tsix sequence is conserved at the human XIC. Tsix RNA has no conserved ORFs, is seen exclusively in the nucleus and is localized at Xic. Before the onset of X inactivation, Tsix is expressed from both X chromosomes. At the onset of X inactivation, Tsix expression becomes monoallelic, is associated with the future active X and persists until Xist is turned off. Tsix is not found on the inactive X once cells enter the X-inactivation pathway. Tsix has features suggesting a role in regulating the early steps of X inactivation, but not the silencing step.

Genetic analysis of the mouse X inactivation center defines an 80-kb multifunction domain

Dosage compensation in mammals occurs by X inactivation, a silencing mechanism regulated in cis by the X inactivation center (Xic). In response to developmental cues, the Xic orchestrates events of X inactivation, including chromosome counting and choice, initiation, spread, and establishment of silencing. It remains unclear what elements make up the Xic. We previously showed that the Xic is contained within a 450-kb sequence that includes Xist, an RNA-encoding gene required for X inactivation. To characterize the Xic further, we performed deletional analysis across the 450-kb region by yeast-artificial-chromosome fragmentation and phage P1 cloning. We tested Xic deletions for cis inactivation potential by using a transgene (Tg)-based approach and found that an 80-kb subregion also enacted somatic X inactivation on autosomes. Xist RNA coated the autosome but skipped the Xic Tg, raising the possibility that X chromosome domains escape inactivation by excluding Xist RNA binding. The autosomes became late-replicating and hypoacetylated on histone H4. A deletion of the Xist 5' sequence resulted in the loss of somatic X inactivation without abolishing Xist expression in undifferentiated cells. Thus, Xist expression in undifferentiated cells can be separated genetically from somatic silencing. Analysis of multiple Xic constructs and insertion sites indicated that long-range Xic effects can be generalized to different autosomes, thereby supporting the feasibility of a Tg-based approach for studying X inactivation.

Colorectal mucinous carcinoma: findings on MRI

PURPOSE

The purpose of this work was to define the characteristic MR features of colorectal mucinous carcinomas and to correlate the mucin pool with the signal intensity of this tumor.

METHOD

MRI of 12 cases of pathologically proven colorectal carcinoma containing mucin was evaluated. We analyzed the signal intensity of tumor on T1- and T2-weighted MR images and correlated the area of intratumoral high signal intensity on T2-weighted images with the mucinous pool on the pathologic specimens. Two radiologists independently estimated the area of high signal intensity in the tumor on T2-weighted images and one pathologist estimated the amount of mucinous pool in the pathologic specimen.

RESULTS

In 9 (75%) of 12 cases, focal or diffuse high signal intensity areas were detected on T2-weighted fast spin echo images. In seven cases in which mucin pools were seen macroscopically, partial (n = 3) or diffuse high signal intensity areas were noted on the T2-weighted images. Among the five cases in which microscopic mucinous pools were detected on the pathologic slides, three cases showed no high signal foci on MR images, and in the remaining two cases, high signal intensity areas were noted as small foci.

CONCLUSION

Intratumoral high signal intensity on T2-weighted fast spin echo MR images occurs in mucinous carcinomas and correlates with the mucin pools on pathologic specimens.

Air pollution and daily mortality in Seoul and Ulsan, Korea

The relationship between air pollution and daily mortality for the period 1991-1995 was examined in two Korean cities, Seoul and Ulsan. The observed concentrations of sulfur dioxide (SO2; mean = 28.7 ppb), ozone (O3; mean = 29.2 ppb), and total suspended particulates (TSP; mean = 82.3 microg/m3) during the study period were at levels below Korea's current ambient air quality standards. Daily death counts were regressed separately in the two cities, using Poisson regression on SO2, O3, and/or TSP controlling for variability in the weather and seasons. When considered singly in Poisson regression models controlling for seasonal variations and weather conditions, the nonaccidental mortality associated with a 50-ppb increment in a 3-day moving average of SO2 concentrations, including the concurrent day and the preceding 2 days, was 1.078 [95% confidence interval (CI), 1.057-1.099] for Seoul and 1.051 (CI, 0.991-1.115) for Ulsan. The rate ratio was 1.051 (CI, 1.031-1.072) in Seoul and 0.999 (CI, 0. 961-1.039) in Ulsan per 100 microg/m3 for TSP, and 1.015 (CI, 1. 005-1.025) in Seoul and 1.020 (0.889-1.170) in Ulsan per 50 ppb for 1-hr maximum O3. When TSP was considered simultaneously with other pollutants, the TSP association was no longer significant. We observed independent pollution effects on daily mortality even after using various approaches to control for either weather or seasonal variables in the regression model. This study demonstrated increased mortality associated with air pollution at both SO2 and O3 levels below the current World Health Organization recommendations.

Comparison of methods of point estimation in occupational epidemiologic studies

Two common study designs of occupational epidemiologic studies are cohort mortality studies, which use the population at risk as a denominator, and proportionate mortality studies, which use the total number of events as a denominator. This study compared the various methods of point estimation for cohort mortality studies, i.e., RR (risk ratio), OR (odds ratio) and SMR (standardized mortality ratio), and those for proportionate mortality studies, i.e., PRR (proportionate risk ratio), POR (proportionate odds ratio) and PMR (proportionate mortality ratio). This study was based on a real dataset of all workers in Metropolitan Toronto, Canada, who applied for compensation for various types of injuries or diseases from the Workers' Compensation Board in 1980. Results showed that within the cohort mortality or proportionate mortality study designs, OR (or POR) in all cases gave the least conservative estimates (farthest away from the null value), while SMR (or PMR) gave the most conservative estimates. The empirical differences between the point estimators were generally small. Our results showed that between study designs the corresponding point estimators were poorly correlated. In addition, this empirical study indicated that the use of the mortality odds ratio did not improve the proportionate mortality study very much in terms of generating results similar to the risk ratio from the cohort mortality design. We drew two conclusions: first, the point estimators within each study design can generally be a good alternative to one another; and second, proportionate mortality studies are not a good approximation for cohort mortality studies.

Combined transcatheter arterial chemoembolization and local radiotherapy of unresectable hepatocellular carcinoma

PURPOSE

The best prognosis in hepatocellular carcinoma (HCC) can be achieved with surgical resection; however, the number of resected cases are limited due to advanced lesions or associated liver disease. The purpose of this study was to investigate the efficacy and toxicity of a prospective trial of combined transcatheter arterial chemoembolization (TACE) and local radiotherapy (RT) in unresectable HCC.

METHODS AND MATERIALS

Patients with histologically proven unresectable HCC due to either advanced lesions or associated cirrhosis were eligible. From March 1992 to August 1994, 30 patients were entered into this study. TACE was performed with Lipiodol (5 ml) and doxorubicin (Adriamycin ; 50 mg), followed by gelatin sponge particle (Gelfoam) embolization. Local RT was started within 7-10 days following TACE. Mean tumor dose was 44.0+/-9.3 Gy in daily 1.8 Gy fractions. Response was assessed by computerized tomography (CT) scan 4-6 weeks following completion of the treatment and then at 1-3-month intervals. Survival was calculated from the start of TACE using the Kaplan-Meier method.

RESULTS

An objective response was observed in 19 patients, giving a response rate of 63.3%. Distant metastasis occurred in 10 patients, with 8 in the lung only and 2 in both lung and bone. Survival rates at 1, 2, and 3 years were 67%, 33.3%, and 22.2%, respectively. Median survival was 17 months. There were 6 patients surviving more than 3 years. Toxicity included transient elevation of liver function tests in all patients, fever in 20, thrombocytopenia in 4, and nausea and vomiting in 1. There was no treatment-related death.

CONCLUSION

Combined TACE and local RT is feasible and tolerable. It gives a 63.3% response rate with median survival of 17 months. We feel that this regimen would be a new promising modality in unresectable HCC. Further study is required to compare the therapeutic efficacy of this regimen to TACE alone.

Separation of enantiomers by capillary electrophoresis using pentosan polysulfate

Pentosan polysulfate, a semisynthetic polysaccharide, was employed as a chiral run buffer additive in capillary electrophoresis. Twenty-eight racemic analytes were resolved. The separations were successful only at low pH when the analytes were significantly protonated. This suggests that ionic interactions were the dominant associative interactions between the anionic pentosan polysulfate and the positively charged analytes. Compared to other linear, carbohydrate-based chiral selectors (i.e., chondroitin sulfates, heparin and dextran sulfate) pentosan polysulfate has some characteristics common of anionic polysaccharides; yet it has several differences in its structure and properties which account for its unusual enantioselectivity. The effects of pH, concentration of phosphate buffer, concentration of pentosan polysulfate and the type and concentration of organic modifier on the enantiomeric separations were investigated. The optimization of these separations were dependent on the nature of the analytes and could be achieved by the proper choice of experimental conditions.

Third-generation cephalosporins and vancomycin as risk factors for postoperative vancomycin-resistant enterococcus infection

OBJECTIVE

To examine use of third-generation cephalosporins (3GCs) alone and in association with vancomycin hydrochloride as a risk factor for vancomycin-resistant enterococcus (VRE) infection in surgical patients.

DESIGN

Case-control retrospective study analyzing antibiotic use in the 30 days preceding culture of VRE or vancomycin-sensitive enterococcus from an infected site.

SETTING

A large tertiary care teaching hospital.

PATIENTS

Surgical inpatients with VRE infections between September 3, 1993, and January 29, 1997, were matched with patients with vancomycin-sensitive enterococcus infections. Matches were based on surgical procedure, initial infection site, and immunosuppression. Matches were found for 32 of 50 surgical patients with VRE. Twenty matched pairs of patients were recipients of solid organ transplants.

MAIN OUTCOME MEASURES

Multivariate logistic regression analysis was done to examine 3GCs and vancomycin as risk factors for VRE infection. Univariate analysis of use of other antibiotic agents and demographic data was also performed.

RESULTS

Multivariate analysis showed significant differences in the use of 3GCs both alone and concurrently with vancomycin. Univariate analysis also showed higher use of metronidazole, concurrent vancomycin and metronidazole, concurrent vancomycin and ceftazidime, and all antibiotics combined in patients with VRE infections.

CONCLUSIONS

This matched control study showed that use of 3GCs, alone (P=.05) or concurrently with vancomycin (P=.05), was a risk factor for VRE infection in surgical patients. Judicious administration of third-generation antibiotics is warranted in surgical patients with other risk factors for VRE.

Hepatic cavernous hemangioma: sonographic patterns and speed of contrast enhancement on multiphase dynamic MR imaging

OBJECTIVE

Our purpose was to investigate a correlation between the speed of contrast enhancement in patients with hepatic cavernous hemangioma revealed by dynamic MR imaging and the internal echo pattern revealed by sonography.

MATERIALS AND METHODS

Forty-five patients underwent multiphase IV contrast-enhanced dynamic MR imaging that revealed 71 hepatic cavernous hemangiomas less than 4 cm in diameter; the MR findings were compared with the sonographic findings in these patients. On MR imaging, the hemangiomas were classified as rapid-, intermediate-, and slow-enhancing. We classified sonographic features as hypoechoic, iso- or mixed-echoic, and hyperechoic according to the relative echogenicity seen between lesions and the surrounding hepatic parenchyma. Sonographic patterns and MR imaging findings of individual lesions were then compared.

RESULTS

Rapid-enhancing hemangiomas revealed on dynamic MR imaging tended to be hypoechoic on sonography (18/24, 75%; p = .0143), and lesions that were slow-enhancing on MR imaging tended to be hyperechoic (26/29, 90%; p < .0001). Hypoechoic lesions on sonography tended to be rapid-enhancing on dynamic MR imaging (18/18, 100%). Likewise, hyperechoic lesions on sonography tended to be slow-enhancing on MR imaging (26/33, 79%; p = .0009).

CONCLUSION

In most patients with hepatic cavernous hemangiomas, we found that the speed of contrast enhancement on multiphase dynamic MR imaging enabled us to predict the echo pattern in sonography and vice versa.

Testicular carcinoma metastatic to the neck

PURPOSE

To show that a supraclavicular neck mass may be indicative of metastatic testicular carcinoma and to offer further insight into the treatment of residual neck disease.

METHOD

We report six cases of testicular carcinoma metastatic to the neck. All were initially treated with radiation, chemotherapy, or a combination of both depending on histological type.

RESULTS

Neck masses persisted despite primary therapy. Three patients underwent subsequent modified neck dissection and remained free of disease; three others received nonsurgical forms of adjuvant therapy and ultimately died of their cancer.

CONCLUSION

Metastatic testicular carcinoma may manifest as a supraclavicular neck mass and must therefore be considered in the differential diagnosis of a mass in this region. Surgical resection is indicated in the management of neck masses that persist after cytoreductive chemotherapy to remove residual foci of disease and potential source of spread.

Purification of Sepharose-unbinding ricin from castor beans (Ricinus communis) by hydroxyapatite chromatography

Sepharose-unbinding ricin was one-step separated and purified from a crude extract of castor beans (Ricinus communis) by affinity chromatography on hydroxyapatite. This purification method does not require the time-consuming and complicated steps, such as gel filtration and ion-exchange chromatography, that have been essential in the separation of Sepharose-unbinding toxins. Using this method, approximately 180 mg of ricin was obtained from 100 g of castor beans using a bed volume of 80 ml on a hydroxyapatite column. Weak affinity of the ricin on Sepharose was confirmed and compared with Sepharose-binding ricin (ricin D), using radioiodinated ricins. The molecular mass of the ricin was estimated to be 62 kDa by 10% SDS-PAGE under nonreducing conditions. Under reducing conditions, the purified ricin appeared to be two subunits, corresponding to the molecular masses of 30 and 32 kDa. The pI value was determined to be approximately 8.9 for the ricin. Uptake of the ricin by HeLa cells was measured as almost half of ricin D uptake. Similar results were observed on CEM cells as well. In vitro cytotoxicity of ricins on different cell lines was measured by the MTT method. When compared with ricin D, the purified ricin showed approximately 10-fold less cytotoxicity to HUT78 or K562 cells and 30-fold less toxicity to CEM cells. This lower cytotoxicity of the ricin may be due to its lower cell-binding properties as evidenced by its low affinity for the cell surfaces. From these results, the purified ricin was considered to be ricin E.

Aversive gustatory stimulation activates limbic circuits in humans

Animal studies implicate the amygdala and its connections in the recognition of aversive stimuli. A recent PET study demonstrated that the human amygdala and left orbitofrontal cortex show substantial increases in regional cerebral blood flow (rCBF) during exposure to aversive odourants. To examine if aversive gustatory stimuli similarly activate these regions, nine healthy women tasted an aversive saline solution, pure water and chocolate while rCBF was measured with PET. The aversive saline condition, when contrasted with the water condition, increased activity in the right amygdala, left anterior orbitofrontal cortex, medial thalamus, pregenual and dorsal anterior cingulate, and the right hippocampus. The right amygdala, left orbitofrontal cortex and pregenual cingulate remained significantly activated when saline was compared with chocolate. The present results indicate that the amygdala and orbitofrontal cortex respond to aversive stimuli in both the olfactory and gustatory modalities, and highlight the role of the pregenual cingulate in negative emotional processing.

MR imaging during arterial portography for assessment of hepatocellular carcinoma: comparison with CT during arterial portography

OBJECTIVE

The purpose of this study was to document the usefulness of MR imaging during arterial portography (MRAP) versus CT during arterial portography (CTAP) in the diagnosis and assessment of hepatocellular carcinoma.

SUBJECTS AND METHODS

In addition to static T1- and T2-weighted MR imaging, MRAP was performed immediately after hepatic angiography through contrast material injection into intraarterially placed catheters (superior mesenteric or splenic artery) in 21 patients with nodular hepatocellular carcinoma. CTAP was performed afterward for each patient. The sensitivity and specificity of MRAP for lesion detection and the differential diagnosis of hepatocellular carcinoma were compared with the sensitivity and specificity of CTAP.

RESULTS

MRAP revealed more perfusion defects (n = 56) than did CTAP (n = 46). The sensitivity for detection of hepatocellular carcinoma was higher for MRAP (94%) than for CTAP (83%); however, the difference was not statistically significant (p > .05). More hepatocellular nodules with unknown malignant potential were revealed on MRAP (n = 7) than on CTAP (n = 2). For the differential diagnosis of perfusion defects commonly revealed by both techniques, more benign lesions and pseudolesions (n = 14) were shown on MRAP through the combined interpretation with static images than on unenhanced and contrast-enhanced CTAP (n = 11).

CONCLUSION

Because of its high sensitivity and its ability to enable radiologists to differentiate benign from malignant conditions, MRAP may have merit compared with CTAP in the assessment of hepatocellular carcinoma.

Recommended practices for surveillance. Association for Professionals in Infection Control and Epidemiology, Inc. Surveillance Initiative working Group

Demonstration of quality health care includes documentation of outcomes of care. Surveillance is a comprehensive method of measuring outcomes and related processes of care, analyzing the data, and providing information to members of the health care team to assist in improving those outcomes. Surveillance is an essential component of effective clinical programs designed to reduce the frequency of adverse events such as infection or injury. Although there is no single or "right" method of surveillance design or implementation, sound epidemiologic principles must form the foundation of effective systems and must be understood by key participants in the surveillance program and supported by senior management. Teamwork and collaboration across the health care spectrum are important for the development of surveillance plans. Each health care organization must tailor its surveillance systems to maximize resources by focusing on population characteristics, outcome priorities, and organizational objectives. To ensure quality of surveillance, the following elements must be incorporated: A written plan should serve as the foundation of any surveillance program. The plan should outline important objectives and elements of the surveillance process so that resources can be targeted appropriately. Thoroughness or intensity of surveillance for an area of interest must be maintained at the same level over time. Fluctuations of a surveillance rate have no meaning unless the same level of data collection is maintained. External rate comparisons are meaningless unless the systems used have comparable intensity. All the elements of surveillance should be used with consistency over time. This includes application of surveillance definitions and rate calculation methods. Personnel resources need to be appropriate for the type of surveillance being performed. This includes trained professionals who understand epidemiology and who have access to continuing professional education opportunities. Other resources essential to surveillance include computer support, information and technology services, clerical services, and administrative understanding and support to maintain a quality program. As a means of quality control and to ensure accuracy, the data and process of surveillance should undergo periodic evaluation and validation. This document is intended to assist professionals who plan and conduct surveillance programs as well as those who assure that there is appropriate organizational support to accomplish appropriate surveillance. While design of surveillance systems must be unique for each organization, incorporation of these seven core Recommended Practices for Surveillance provides a scientific framework to approach surveillance programs.