Learning from data in dentistry: Summary of the third annual OpenWide conference

The overarching goal of the third scientific oral health symposium was to introduce the concept of a learning health system to the dental community and to identify and discuss cutting-edge research and strategies using data for improving the quality of dental care and patient safety. Conference participants included clinically active dentists, dental researchers, quality improvement experts, informaticians, insurers, EHR vendors/developers, and members of dental professional organizations and dental service organizations. This report summarizes the main outputs of the third annual OpenWide conference held in Houston, Texas, on October 12, 2022, as an affiliated meeting of the American Dental Association (ADA) 2022 annual conference.

Patient and dentist perspectives on collecting patient reported outcomes after painful dental procedures in the National Dental PBRN

BACKGROUND

Dental Patient Reported Outcomes (PROs) relate to a dental patient's subjective experience of their oral health. How practitioners and patients value PROs influences their successful use in practice.

METHODS

Semi-structured interviews were conducted with 22 practitioners and 32 patients who provided feedback on using a mobile health (mHealth) platform to collect the pain experience after dental procedures. A themes analysis was conducted to identify implementation barriers and facilitators.

RESULTS

Five themes were uncovered: (1) Sense of Better Care. (2) Tailored Follow-up based on the dental procedure and patient's pain experience. (3) Effective Messaging and Alerts. (4) Usable Digital Platform. (5) Routine mHealth Integration.

CONCLUSION

Frequent automated and preferably tailored follow-up messages using an mHealth platform provided a positive care experience for patients, while providers felt it saved them time and effort. Patients thought that the mHealth questionnaires were well-developed and of appropriate length. The mHealth platform itself was perceived as user-friendly by users, and most would like to continue using it.

PRACTICAL IMPLICATIONS

Patients are prepared to use mobile phones to report their pain experience after dental procedures. Practitioners will be able to close the post-operative communication gap with their patients, with little interruption of their workflow.

Identifying Contributing Factors Associated With Dental Adverse Events Through a Pragmatic Electronic Health Record-Based Root Cause Analysis

OBJECTIVE

This study assessed contributing factors associated with dental adverse events (AEs).

METHODS

Seven electronic health record-based triggers were deployed identifying potential AEs at 2 dental institutions. From 4106 flagged charts, 2 reviewers examined 439 charts selected randomly to identify and classify AEs using our dental AE type and severity classification systems. Based on information captured in the electronic health record, we analyzed harmful AEs to assess potential contributing factors; harmful AEs were defined as those that resulted in temporary moderate to severe harm, required hospitalization, or resulted in permanent moderate to severe harm. We classified potential contributing factors according to (1) who was involved (person), (2) what were they doing (tasks), (3) what tools/technologies were they using (tools/technologies), (4) where did the event take place (environment), (5) what organizational conditions contributed to the event? (organization), (6) patient (including parents), and (7) professional-professional collaboration. A blinded panel of dental experts conducted a second review to confirm the presence of an AE.

RESULTS

Fifty-nine cases had 1 or more harmful AEs. Pain occurred most frequently (27.1%), followed by nerve injury (16.9%), hard tissue injury (15.2%), and soft tissue injury (15.2%). Forty percent of the cases were classified as "temporary not moderate to severe harm." Person (training, supervision, and fatigue) was the most common contributing factor (31.5%), followed by patient (noncompliance, unsafe practices at home, low health literacy, 17.1%), and professional-professional collaboration (15.3%).

CONCLUSIONS

Pain was the most common harmful AE identified. Person, patient, and professional-professional collaboration were the most frequently assessed factors associated with harmful AEs.

Study protocol: understanding pain after dental procedures, an observational study within the National Dental PBRN

BACKGROUND

Patient-reported outcome measures provide an essential perspective on the quality of health care provided. However, how data are collected, how providers value and make sense of the data, and, ultimately, use the data to create meaningful impact all influence the success of using patient-reported outcomes.

OBJECTIVES

The primary objective is to assess post-operative pain experiences by dental procedure type through 21 days post-procedure as reported by patients following dental procedures and assess patients' satisfaction with pain management following dental surgical procedures. Secondary objectives are to: 1) assess post-operative pain management strategies 1 week following dental surgical procedures, as recommended by practitioners and reported by patients, and 2) evaluate practitioner and patient acceptance of the FollowApp.Care post visit patient monitoring technology (FollowApp.Care). We will evaluate FollowApp.Care usage, perceived usefulness, ease of use, and impact on clinical workload.

DESIGN AND METHODS

We describe the protocol for an observational study involving the use of the FollowApp.Care platform, an innovative mobile application that collects dental patients' assessments of their post-operative symptoms (e.g., pain). The study will be conducted in collaboration with the National Dental Practice-based Research Network, a collective Network of dental practices that include private and group practices, public health clinics, community health centers and Federal Qualified Health Centers, academic institutional settings, and special patient populations. We will recruit a minimum of 150 and up to 215 dental providers and up to 3147 patients who will receive push notifications through text messages FollowApp.Care on their mobile phones at designated time intervals following dental procedures. This innovative approach of implementing an existing and tested mobile health system technology into the real-world dental office setting will actively track pain and other complications following dental procedures. Through patients' use of their mobile phones, we expect to promptly and precisely identify specific pain levels and other issues after surgical dental procedures. The study's primary outcome will be the patients' reported pain experiences. Secondary outcomes include pain management strategies and medications implemented by the patient and provider and perceptions of usefulness and ease of use by patients and providers.

Dental caries as a risk factor for bacterial blood stream infection (BSI) in children undergoing hematopoietic cell transplantation (HCT)

Background

Hematopoietic cell transplantation (HCT) is a potentially curative therapy for a wide range of pediatric malignant and nonmalignant diseases. However, complications, including blood stream infection (BSI) remain a major cause of morbidity and mortality. While certain bacteria that are abundant in the oral microbiome, such as S. mitis, can cause BSI, the role of the oral microbial community in the etiology of BSI is not well understood. The finding that the use of xylitol wipes, which specifically targets the cariogenic bacteria S. mutans is associated with reduced BSI in pediatric patients, lead us to investigate dental caries as a risk factor for BSI.

Methods

A total of 41 pediatric patients admitted for allogenic or autologous HCT, age 8 months to 25 years, were enrolled. Subjects with high dental caries risk were identified as those who had dental restorations completed within 2 months of admission for transplant, or who had untreated decay. Fisher's exact test was used to determine if there was a significant association between caries risk and BSI. Dental plaque and saliva were collected on a cotton swab from a subset of four high caries risk (HCR) and four low caries risk (LCR) children following pretransplant conditioning. 16SrRNA sequencing was used to compare the microbiome of HCR and LCR subjects and to identify microbes that were significantly different between the two groups.

Results

There was a statistically significant association between caries risk and BSI (p < 0.035) (Fisher's exact test). Multivariate logistic regression analysis showed children in the high dental caries risk group were 21 times more likely to have BSI, with no significant effect of age or mucositis severity. HCR subjects showed significantly reduced microbial alpha diversity as compared to LCR subjects. LEfse metagenomic analyses, showed the oral microbiome in HCR children enriched in order Lactobacillales. This order includes Streptococcus and Lactobacillus, both which contain bacteria primarily associated with dental caries.

Discussion

These findings support the possibility that the cariogenic microbiome can enhance the risk of BSI in pediatric populations. Future metagenomic analyses to measure microbial differences at, before, and after conditioning related to caries risk, may further unravel the complex relationship between the oral microbiome, and whether it affects health outcomes such as BSI.

Flavored Cannabis Product Use Among Adolescents in California

Given the well-documented role of flavors in encouraging tobacco use among adolescents and diversity of the cannabis market, we describe flavored cannabis product use, both smoked and aerosolized ("vaped"), among a sample of adolescents. We surveyed 1,423 students in 8 Northern and Central California public high schools (2019-2020) to record flavored tobacco and cannabis use. Among past 30-day cannabis users, use of flavored cannabis, most often fruit-flavored, was common for smoked (48.1%) and vaped (58.0%) products. Given that youth-appealing flavors may contribute to underage cannabis use, emerging cannabis control policies should consider lessons from tobacco control to prevent youth cannabis use.

California Dentists' Engagement in Media Advocacy for Sugar Restriction Policies

OBJECTIVES

Increasing dentists' visibility in the media to make the case for sugary beverage taxes can help advance public policy that improves oral health outcomes. We assessed California dentists' media engagement behaviors related to sugar restriction policies for dental caries prevention and correlates of engaging in such behavior.

METHODS

Survey items related to sugar policies and media engagement were embedded in an electronically distributed statewide survey of dentists' tobacco cessation counseling behaviors. Descriptive statistics were calculated for respondent characteristics, perceived professional responsibility to discuss selected topics with patients, and attitudes and behaviors related to sugar restriction policy and media communication. Multivariable models identified independent correlates of media engagement.

RESULTS

Of 624 respondents, most had never talked to traditional media (78%) or posted to social media (64%) about sugar or sugar policies for dental caries prevention. Respondents with the highest level of media engagement were more likely to agree that sugary beverage taxes are effective at reducing dental caries, that they had support from dental professional organizations to talk to the media, that it is realistic for patients to reduce their sugar consumption, and that sugar and sugary drinks are extremely harmful to health.

CONCLUSIONS

Efforts to increase dentists' media engagement related to sugar restriction policies for dental caries prevention should address dentists' negative attitudes toward the effectiveness of sugar restriction policies and may require increased support from dental professional societies.

KNOWLEDGE TRANSFER STATEMENT

Study findings identify dentists' low engagement in media advocacy to support sugar restriction policy adoption. The results identify correlates of media engagement and of dentists' willingness and confidence to act, which could serve to inform interventions to support and enhance engagement.

Beverage Advertisement Receptivity Associated With Sugary Drink Intake and Harm Perceptions Among California Adolescents

PURPOSE

Evaluate associations of adolescents' beverage marketing receptivity with sugar-sweetened beverage (SSB) perceived harm and intake.

DESIGN

School-based cross-sectional health behavior survey.

SETTING

Seven rural schools in California, 2019-2020.

SUBJECTS

815 student participants in grades 9 or 10.

MEASURES

Participants viewed 6 beverage advertisement images with brand obscured, randomly selected from a larger pool. Ads for telecommunications products were an internal control. Receptivity was a composite of recognizing, liking, and identifying the displayed brand (later categorized: low, moderate, high). Weekly SSB servings were measured with a quantitative food frequency questionnaire and perceived SSB harm as 4 levels ("no harm" to "a lot").

ANALYSIS

Outcomes SSB intake (binomial regression) and perceived harm (ordered logistic regression) were modeled according to advertisement receptivity (independent variable), with multiple imputation, school-level clustering, and adjustment for presumed confounders (gender, age, screen time, etc.).

RESULTS

In covariable-adjusted models, greater beverage advertisement receptivity independently predicted higher SSB intake (ratio of SSB servings, high vs. low receptivity: 1.48 [95% CI: 1.15, 1.89]) and lower perceived SSB harm (odds ratio, high vs. low receptivity: 0.59 [0.40, 0.88]). Perceived SSB harm was inversely associated with SSB intake.

CONCLUSION

Beverage advertisement receptivity was associated with less perceived SSB harm and greater SSB consumption in this population. Policy strategies, including marketing restrictions or counter-marketing campaigns could potentially reduce SSB consumption and improve health.

Electronic cigarette and moist snuff product characteristics independently associated with youth tobacco product perceptions

INTRODUCTION

Tobacco product characteristics convey product attributes to potential users. This study aimed to assess independent contributions of specific e-cigarette and smokeless tobacco product characteristics to adolescents' perceptions about these products.

METHODS

In 2019-2020, students (N=1003) attending a convenience sample of 7 high schools in California (USA) were individually randomized to one of two discrete choice experiments, featuring either electronic cigarettes (e-cigarettes) or moist snuff. Participants were presented like-product pairs of randomlygenerated hypothetical tobacco products differing in device type, flavor, vapor cloud, and nicotine amount (for e-cigarettes) or differing in brand, flavor, cut, and price (for moist snuff). Within pairs, participants were asked about which product they were more curious, was more dangerous, would give a greater 'buzz,' and would be easier to use. Conditional logistic regression was used to quantify independent associations of product characteristics to participants' choices.

RESULTS

Each e-cigarette and moist snuff characteristic was independently associated with multiple product perceptions. All non-tobacco flavors were associated with more curiosity and perceived ease-of-use but lower perceived danger. Tank and pod-type e-cigarettes were viewed as easier to use and garnered more curiosity than 'cigalike' or 'drip-mod' devices. Smaller vapor cloud e-cigarettes and lower-price moist snuff were viewed as less dangerous, less buzz-inducing, and easier to use. Product ever users held stronger perceptions than never users about device type (e-cigarettes) and brands (moist snuff), while product naïve participants more strongly associated flavor with danger and buzz.

CONCLUSIONS

Tobacco product characteristics convey product attributes to adolescents that may increase appeal. Restricting specific characteristics, including flavors, could reduce positive perceptions of these products among youth.

Dental Professionals' Engagement in Tobacco, Electronic Cigarette, and Cannabis Patient Counseling

OBJECTIVES

California features low smoking prevalence, cautionary electronic cigarette (e-cigarette) public messaging, and legal recreational cannabis: a unique landscape for dental professionals to navigate tobacco cessation promotion. This cross-sectional study assessed California dental professionals' self-reported tobacco patient counseling behaviors and the correlates of providing such assistance.

METHODS

Statewide surveys of dental hygienists (n = 701) and dentists (n = 725) were distributed electronically. The dentist survey was weighted for sampling and nonresponse. Prevalence of asking patients about use was compared for cigarette and noncigarette products (e.g., e-cigarettes, cannabis). Multivariable models identified independent correlates of providing cessation assistance to tobacco-using patients.

RESULTS

Respondents reported frequently (often/always) documenting patient tobacco use (hygienists: 80%; dentists: 73%) but less commonly provided forms of assistance (hygienists: 27%-49%; dentists: 10%-31%). Most respondents asked patients about cigarette smoking, but noncigarette product use (cigar, hookah, pipe, e-cigarette, or cannabis) was not commonly assessed. Greater confidence and willingness to assist were positively associated with providing assistance in multivariable models, but perceived barriers (e.g., lack of time and remuneration) were not. Results were robust to model specifications.

CONCLUSIONS

California dental professionals often ask about smoking but lag in providing cessation assistance and inquiring about noncigarette products. Successful efforts to encourage dental professionals' engagement in tobacco prevention and cessation must enhance providers' self-efficacy and motivation and likely will require system and organizational change.

KNOWLEDGE TRANSFER STATEMENT

Study findings identify substantial gaps in dental professionals' engagement in patient tobacco cessation. The results identify correlates of providing assistance and of dental professionals' willingness and confidence to do so, which could serve to inform interventions to support and enhance engagement.

Dental Hygienists' and Dentists' Tobacco Cessation Continuing Education Preferences: Application of a Discrete Choice Method

Despite ample opportunity, dental professionals frequently fall short of connecting tobacco-using patients with effective cessation support, often citing lack of training as a barrier. To inform development of training options, the aim of this study was to quantify the preferences of practicing dental hygienists and dentists in California for continuing dental education (CDE) offerings related to tobacco and patient tobacco cessation. Two statewide surveys of California dental hygienists and dentists were conducted. In addition to providing their own and their practice characteristics, in a discrete choice experiment, participants indicated their preferences between pairs of randomly generated hypothetical tobacco cessation CDE offerings that differed in topic, cost, delivery modality, and duration. Ultimately, 641 dental hygienists (20.5% of the total invited minus those with undeliverable emails, n=3,129) and 654 dentists (8.5% of the total invited minus those with undeliverable emails, n=7,669) responded to at least one of the discrete choice items, and their responses were analyzed. The results showed that each CDE attribute was independently associated with preference. Cost and topic were more strongly associated with preference than were delivery modality and duration. Lower cost, shorter duration courses were generally favored. Alternative tobacco products and patient communication were the most popular topics for participating dental hygienists and dentists, respectively. CDE preferences differed according to participant characteristics: live webinars were the least preferred modality for more experienced dental professionals, and shorter courses were not preferred by dentists in non-urban locations. These findings showed that these dental professionals considered multiple attributes in selecting CDE courses. To reach the broadest audience, CDE providers should offer low-cost options across a range of delivery modalities, such as full-day workshops in rural areas and online webinars for earlier career professionals.

Predictors of Smokeless Tobacco Susceptibility, Initiation, and Progression Over Time Among Adolescents in a Rural Cohort

BACKGROUND

Use of smokeless tobacco (ST, moist snuff and chewing tobacco) is elevated among male rural youth, particularly participants in certain sports, including baseball.

OBJECTIVES

This study aimed to assess factors associated with adolescent male athletes' ST-related behaviors over time, including: baseline use, initiation, and progression in use intensity in a school-based longitudinal cohort.

METHODS

Baseline and one-year follow-up questionnaires assessed sociodemographic characteristics, environmental factors, and tobacco-related perceptions and behaviors among 9- to12th-grade interscholastic baseball players in 36 rural California schools. Population characteristics were compared among ST use categories (never, experimental, and experienced users). Multivariable models using generalized estimating equations were estimated for outcomes among baseline ST never-users (ST susceptibility and future initiation) and experimenters (ST expectations and progression in ST use).

RESULTS

Of 594 participants, over half (57%) had ever tried a tobacco product and the most common products tried were ST (36%) and electronic cigarettes (36%). Being older, perceiving less ST harm, being Non-Hispanic White, using alcohol or other tobacco products, having family or friends who use ST, and being receptive to advertising were associated with greater baseline ST use. Baseline alcohol consumption, lower perceived ST harm, peer use, and susceptibility and expectations were predictive of ST initiation and/or progression at one-year follow-up. Conclusion/Importance: Certain environmental, socio-demographic, cognitive, and behavioral factors predict ST susceptibility and later initiation and progression in use. Interventions addressing these factors have potential to prevent ST uptake and continued use within this high-risk adolescent population.

Value of 100 kVp scan with sinogram-affirmed iterative reconstruction algorithm on a single-source CT system during whole-body CT for radiation and contrast medium dose reduction: an intra-individual feasibility study

AIM

To perform an intra-individual investigation of the usefulness of a contrast medium (CM) and radiation dose-reduction protocol using single-source computed tomography (CT) combined with 100 kVp and sinogram-affirmed iterative reconstruction (SAFIRE) for whole-body CT (WBCT; chest-abdomen-pelvis CT) in oncology patients.

MATERIALS AND METHODS

Forty-three oncology patients who had undergone WBCT under both 120 and 100 kVp protocols at different time points (mean interscan intervals: 98 days) were included retrospectively. The CM doses for the 120 and 100 kVp protocols were 600 and 480 mg iodine/kg, respectively; 120 kVp images were reconstructed with filtered back-projection (FBP), whereas 100 kVp images were reconstructed with FBP (100 kVp-F) and the SAFIRE (100 kVp-S). The size-specific dose estimate (SSDE), iodine load and image quality of each protocol were compared.

RESULTS

The SSDE and iodine load of 100 kVp protocol were 34% and 21%, respectively, lower than of 120 kVp protocol (SSDE: 10.6±1.1 versus 16.1±1.8 mGy; iodine load: 24.8±4versus 31.5±5.5 g iodine, p<0.01). Contrast enhancement, objective image noise, contrast-to-noise-ratio, and visual score of 100 kVp-S were similar to or better than of 120 kVp protocol.

CONCLUSION

Compared with the 120 kVp protocol, the combined use of 100 kVp and SAFIRE in WBCT for oncology assessment with an SSCT facilitated substantial reduction in the CM and radiation dose while maintaining image quality.

Prognostic Factors in Liver Metastases after Transcatheter Arterial Embolization or Arterial Infusion

From January 1986 to December 1988, 85 patients (55 men and 30 women, mean age 59 years) with metastatic liver tumors were treated with hepatic artery embolization (TAE) or infusion (HAI). Sixty-eight patients with successful catheterization were treated with TAE using iodized oil (Lipiodol) mixed with anticancer agent (ACA). In 12 of 68 patients with hypervascular tumors gelatin sponge was added. Patients with unsuccessful catheterization were treated with hepatic artery infusion of ACA. Forty-three patients received oral chemotherapy following TAE or HAI. Overall, the 6-month, and 1- and 2-year survival rates were 69.5, 31.8 and 4.1 per cent, respectively (mean 233 days). A univariate analysis of prognostic factors showed that number of metastases, stage, treatment times and oral chemotherapy were all significant factors (p<0.05). Ascites, jaundice, percentage of hepatic replacement and treatment protocol also had some influence (p<0.1). Sex, age, primary site, elevation of tumor markers, other metastatic lesions, portal vein involvement and difference in anticancer agent had no prognostic significance. A multivariate analysis using Cox's proportional hazard model revealed that the number of treatments had the most important prognostic significance, followed by oral chemotherapy, stage and percentage of hepatic replacement.

Differential Diagnosis of Gastric Adenoma and Type IIA Early Gastric Cancer

The endoscopic and radiographic findings of 45 gastric adenomas in 39 patients were followed for 6 months to 13 years and compared with type IIa early gastric cancer observed in 9 patients. Difficulties in the differential diagnosis of these disorders were evaluated. The following features were suggestive of gastric adenomas: clustered lesions; protuberance with gentle slope; smooth surface; and relatively young patients. Discrimination of adenoma from type IIa early gastric cancer is often difficult by visual observation alone; biopsy was essential in most patients. A group III adenoma verified on biopsy should be followed closely because the lesion may harbor a cancer (so-called carcinoma-in-adenoma) or a cancer may later develop.

Familial multiple trichoepithelioma associated with subclavian-pulmonary collateral vessels and cerebral aneurysm--case report

A 63-year-old woman presented with cerebellar infarction caused by occlusion of the right posterior inferior cerebellar artery. She had papules on her face that were identified histologically as multiple trichoepithelioma. Angiography revealed right subclavian-pulmonary collateral vessels and a cerebral aneurysm arising from the bifurcation of the right middle cerebral artery. Her grandmother, mother, and uncle had had similar papules, and the deaths of her mother and uncle were due to subarachnoid hemorrhage.

Clinical evaluation of aortic diseases using nonenhanced MRA with ECG-triggered 3D half-Fourier FSE

The efficacy of the nonenhanced magnetic resonance angiography (MRA) technique known as fresh-blood imaging (FBI), using electrocardiograph (ECG)-triggered 3D half-Fourier fast spin-echo (FSE), was evaluated for the detection and characterization of aortic diseases. Seventy-five consecutive patients with aortic disease underwent the FBI examination on a 1.5-T clinical imager. The results showed that the FBI technique permits clear visualization of aortic diseases, and the vessel branches and their relationship, which provides valuable information. Therefore, the nonenhanced FBI technique is appropriate to use for screening purposes.

[Evaluation of time dependency of the acetazolamide effect on cerebral hemodynamics as measured by 99mTc-ECD single-photon emission computed tomography]

PURPOSE

Kuwabara et al. have examined the cerebral artery dilation with acetazolamide (ACZ) challenge test using PET. And, they reported that ACZ reaction came out time dependently. We have developed a unique SPECT's method using Technetium-99m ethyl cysteinate dimer (99mTc-ECD) to verify the results obtained by Kuwabara et al.

METHOD

1000 MBq of 99mTc-ECD was exactly divided into three syringes. Each of which was intravenous infused (i.v.) at rest, 7.5, and 20 minutes after ACZ administration. Data collection was started using dynamic SPECT immediately after 99mTc-ECD i.v. at rest. Using necessary data only, SPECT images representing each of the three 99mTc-ECD i.v. was reconstructed. SPECT counts were obtained by the ROI method from each images to calculate relative CBF from rest to 7.5 and 20 minutes after ACZ administration.

RESULT

The 18 hemispheres of nine patients in the negative control group in whom ACZ was not loaded. CBF was stable during the three evaluation. The measurement error our method was estimated as small. The 18 hemispheres of nine patients in the positive control group who has normal vasodilatory reserve, CBF was increased by 26.2 +/- 8.1% at 7.5 minutes and 29.3 +/- 13.1% at 20 minutes after ACZ administration. Seven patients with and chronic stage unilateral internal carotid artery severe stenosis and/or occlusion were evaluated as the test group. Case of unaffected side, CBF was increased by 17.6 +/- 6.9% at 7.5 minutes and 24.8 +/- 11.3% 20 minutes after ACZ administration. And, increase rate of CBF in the affected side was 2.8 +/- 1.6% at 7.5 minutes and 17.3 +/- 5.0% at 20 minutes after ACZ administration. In the affected side, timing of the maximum CBF increase caused by ACZ was remarkably delayed.

CONCLUSION

Our method based on 99mTc-ECD SPECT also revealed delayed cerebral artery dilation in the affected side. It was suggested that ACZ reaction came out time dependently, as reported by Kuwabara et al.

Altered phase relation between sleep timing and core body temperature rhythm in delayed sleep phase syndrome and non-24-hour sleep-wake syndrome in humans

Changes in the phase relation between sleep timing and the circadian pacemaker are suspected to have an etiological significance in circadian rhythm sleep disorders. Simultaneous recordings of rest-activity and rectal temperature in seven sighted delayed sleep phase syndrome (DSPS) patients, seven sighted non-24-h sleep-wake syndrome (non-24) patients, and 14 healthy controls were made for 10-14 days continuously in the subjects' homes. We found that sleep length and the interval from the body temperature (BT) trough to sleep offset were significantly longer in both non-24 and DSPS patients than in the controls, and that the interval between sleep onset and the BT trough was significantly less in the non-24 patients than in the DSPS patients and the controls. We postulate these alterations in phase relation to be associated with phase changes of the circadian pacemaker via different illumination timings.

Creutzfeldt-Jakob disease associated with cadaveric dura mater grafts in Japan

A nationwide survey and recent information documented 57 patients with Creutzfeldt-Jakob disease (CJD) who had received dura mater grafts during the period between January 1979 and September 1999. At least 54 of these 57 patients received the same brand of dura mater graft from the same processor. Mean age at disease onset in the 57 patients with dural grafts was younger (51.9 years) than that in patients with sporadic CJD (63 years) (p < 0. 0001). Initial symptoms were cerebellar ataxia, disorientation, and visual or oculomotor disturbance.

Effects of small dose of brotizolam on P300

Nine healthy men (mean age, 22.2 years) participated in two experimental sessions cross-overed randomly in a double blind manner; one with a placebo and the other with 0.125 mg of brotizolam (BTZ) administered in the morning. Resting electroencephalogram and event-related potential under oddball paradigm was recorded before and 1, 2, 4, 6 and 8 h after the administration. Mean 30-msec bin amplitude from 240 msec to 450 msec after the stimulus was compared between placebo and drug sessions in order to observe P300. Brotizolam reduced the amplitude of P300 at 6 h after administration. It was noted that the effects of BTZ were most marked at Fz.

Melatonin treatment for circadian rhythm sleep disorders

This study investigated the effects of melatonin administration on circadian rhythm sleep disorders, and aimed to clarify clinical characteristics of melatonin responders. The subjects were 46 patients with circadian rhythm sleep disorders: 30 Delayed Sleep Phase Syndrome (DSPS) and 16 non-24 h sleep-wake syndrome (non-24). Patients took 0.3-1.0 mg of melatonin 5, 3 and 1 h before habitual bedtime. Seventeen patients responded to melatonin (12 DSPS, five non-24). Comparison of clinical background between responders and non-responders revealed that the responders were characterized by short total sleep time and later onset age of clinical symptoms.

[Reduction of the influence of the liver uptake to the myocardial uptake on technetium-99m myocardial SPECT; usefulness and problems of a mask processing method]

The aim of this study is to evaluate the usefulness of a mask processing method for obtaining the true myocardial tracer distribution by eliminating the influence of the liver uptake to the myocardial uptake on myocardial SPECT images by using technetium-99m (99mTc) blood flow agents. A SPECT imaging was performed with a two-head SPECT system (GCA-7200A/DI) in both phantom and clinical studies. The mask processing method was applied to the reconstructed and projection images. The phantom consisted of heart, lung, liver and spine. A defect was located in the inferior wall of the left ventricle and other parts of the heart and liver were filled with 99mTc solution. For clinical study 10 patients with difficulty in the interpretation of the inferior wall were selected for the evaluation of usefulness of the mask method. In the phantom study, the mask processing method applied to the reconstructed images was able to remove the overlapped liver from the heart, but was not able to remove the influence of the liver uptake to the myocardial uptake. Nevertheless, the mask processing method applied to the projection images successfully eliminated not only the overlapped liver but also the influence of the liver uptake to the myocardial uptake. In the clinical study, the liver uptake could be removed from the uptake in the inferior wall in 8 of 10 patients with the mask processing methods. In 2 patients, the overlapped liver uptake could not be eliminated from the uptake in the inferior wall because the distance between the liver and heart was too short. The mask processing method applied to the projection images was thought to be superior to that applied to the reconstruction images in both phantom and clinical studies. The mask processing method, especially applied to the projection images, seems to be useful for the elimination of the liver uptake from the inferior wall of the myocardium on myocardial SPECT images using 99mTc blood flow agents.

Metastatic liver tumor from cystic ovarian carcinomas: CT and MRI appearance

OBJECTIVE

The initial and follow-up CT and MRI images of ten patients with hepatic metastases from ovarian tumors were retrospectively analyzed to establish their features and sequential changes in appearance.

MATERIALS AND METHODS

Ten patients with hepatic metastasis from ovarian tumors received initial and follow-up CT and MRI examinations. Six patients were followed up every two to three weeks before surgical tumor resection. Both CT and MR images were analyzed by two radiologists.

RESULTS

A total of fourteen lesions were detected by CT and MRI in 10 patients. All 14 lesions were demonstrated as areas of marked hyperintensity on T2-weighted MRI. Eleven cyst-like tumors were demonstrated as round or oval low density lesions on CT and as areas of hypointensity on T1-weighted imaging. Three lesions were shown as solid masses with slightly low attenuation at the initial CT examination and slightly low or iso-intensity areas on T1-weighted imaging, and these lesions showed early peripheral globular enhancement and delayed enhancement on contrast-enhanced CT and MR imaging. Cystic formation was observed two to three weeks later after initial study in all the 3 solid lesions. Rapid subcapsular effusion, which showed obvious enhancement on delayed Gd-DTPA enhanced MR imaging, was observed in two patients.

CONCLUSION

The hepatic metastatic tumor from cystic ovarian carcinoma may manifest as a well-defined cystic lesion or as a solid mass, and the solid mass shows delayed enhancement on contrast-enhanced CT and MR imaging. Furthermore, rapid cystic formation and rapid subcapsular extension is frequently seen.

Effects of a small dose of triazolam on P300

Ten healthy men (mean age, 33.9 years) participated in two experimental sessions cross-overed randomly in a double-blind manner: one with the placebo and another with 0.125 mg of triazolam (TRZ). Resting electroencephalography and event-related potential under oddball paradigm were recorded before the drug administration, and 1, 2, 4, 6 and 8 h after that. P300 waveforms were analyzed by peak amplitudes and 30-ms bin data. Triazolam may cause cognitive dysfunction without general sedation or apparent sleepiness, and this effect appeared 2 h, 4 h and 6 h, most prominently 6 h, after TRZ administration.

Poor recovery sleep after sleep deprivation in delayed sleep phase syndrome

To clarify disturbances in sleep regulation in patients with delayed sleep phase syndrome (DSPS), we studied three patients with DSPS and seven healthy controls. Sleep propensity and melatonin rhythms after 24-h sleep deprivation were investigated under dim light condition by using the ultra-short sleep-wake schedule. The sleep propensity curves displayed clear differences between DSPS patients and the controls. During the subjective day when melatonin was not produced, recovery sleep after the sleep deprivation did not occur in DSPS patients, while recovery sleep occurred during the subjective day in controls. This suggests that DSPS may involve problems related to the homeostatic regulation of sleep after sleep deprivation.

Incidence rate of Creutzfeldt-Jakob disease in Japan

BACKGROUND

The objective of this study is to clarify the incidence rate of Creutzfeldt-Jakob disease (CJD) during the last decade in Japan.

METHODS

A nationwide mail survey was conducted in all hospitals with a minimum bed capacity of 100 and having at least one of three departments: neurology, psychiatry, and neuropathology. The survey required the patient's sex, date of birth, date of diagnosis, diagnostic criteria, medical history and CJD incidence in the family.

RESULTS

From 493 hospitals throughout the country, 821 patients with CJD were reported from January 1985 through March 1996. The annual incidence rate was 0.49 per million population for males and 0.68 for females. The age-specific incidence rate was highest among those 70-79 years of age, followed by the 60-69, and 50-59 age groups. The incidence and mortality increased during the observed period; however, the incidence rate among younger generations did not rise.

CONCLUSION

A nationwide incidence survey of CJD in Japan revealed the incidence and distribution of the disease over the recent decade. It was found that the incidence and mortality rates had increased during the observed period.

[Technical investigation of cerebral blood flow measurements using the Patlak Plot method--a contrivance for positioning of the gamma camera at data collection in radionuclide angiography]

The time-activity curve for the aortic arch obtained from radionuclide angiography (RNA) is handled as an input function parameter according to the method of Matsuda et al., which determines regional cerebral blood flow non-invasively. The data are collected from a frontal view of the thorax captured by RNA by their method, however we encountered a case in which it was difficult to identify aortic arch in the data collection from the frontal view. The precise identification of the aortic arch was implemented when the RNA data were collected from the left anterior oblique view of the thorax. No significant difference was noted in the measured values between the data collection from the frontal view and from the left anterior oblique view. Our method seems to be useful modification of the Patlak plot method.

Power Doppler sonography assessment of tumor recurrence after chemoembolization therapy for hepatocellular carcinoma

OBJECTIVE

This study was undertaken to determine the value of power Doppler sonography in the evaluation of recurrent hepatocellular carcinomas after transcatheter arterial chemoembolization therapy.

SUBJECTS AND METHODS

Forty-five patients (age range, 45-81 years; mean age, 61 years) with hepatocellular carcinomas prospectively underwent power Doppler sonography, helical CT, and intraarterial digital subtraction angiography before and after transcatheter arterial chemoembolization therapy to evaluate for tumor recurrence. Three to 6 months after transcatheter arterial chemoembolization therapy, the Doppler signal, its location, and shape were evaluated. The results were compared with tumor vascularity as determined on helical CT and intraarterial digital subtraction angiography, which were used as the gold standards (n = 142).

RESULTS

A sonographic signal was seen in 80 of 142 lesions with power Doppler sonography. Flow signal in lesions tended to be more difficult to detect in the left lobe (sensitivity, 74%) than in the right lobe (sensitivity, 93%). The location of the color signal was in the tumor's center, on its periphery, or both. No correlation between tumor recurrence and the location of a signal within a tumor was found. Power Doppler sonography had a sensitivity of 87%, a specificity of 85%, and an accuracy of 86% in revealing tumor recurrence after transcatheter arterial chemoembolization therapy. All lesions that showed linear signals in the center or at the periphery of the tumors proved to be recurring tumors (n = 20). In lesions with spotty signals, tumor recurrence was not revealed in nine of 60 lesions.

CONCLUSION

Power Doppler sonography can be used for follow-up studies after transcatheter arterial chemoembolization therapy as a sensitive and cost-effective imaging technique. Although spotty signals were frequently seen, linear signals appeared to be specific for tumor recurrence.

The effects of transjugular intrahepatic portosystemic shunt on portal hypertensive gastropathy

In addition to variceal bleeding, haematemesis may occur due to haemorrhagic gastritis in patients with portal hypertension. This has been known as portal hypertensive gastropathy (PHG). We have evaluated the effects of the transjugular intrahepatic portosystemic shunt (TIPS) on portal venous pressure (PVP) and endoscopic gastric mucosal changes observed in patients with portal hypertension. We performed TIPS in 12 patients with complications due to portal hypertension as follows: variceal bleeding in nine patients (bleeding from oesophageal varices in seven and gastric varices in two), refractory ascites in three and haemorrhage from severe PHG in one. Endoscopic examinations were performed before and after TIPS for all patients. Changes of PVP and gastric mucosal findings on endoscopy were analysed. Before TIPS, PHG was seen in 10 patients. Portal venous pressure decreased from an average of 25.1+/-8.8 to 17.1+/-6.2 mmHg after TIPS (P<0.005). On endoscopy, PHG improved in nine of 10 patients. Oesophagogastric varices improved in eight of 11 patients. In one patient with massive haematemesis, haemorrhage from severe PHG completely stopped after TIPS. Because TIPS effectively reduced PVP, this procedure appeared to be effective for the treatment of uncontrollable PHG.

Mucin-producing tumor of the pancreas: diagnostic value of diffusion-weighted echo-planar MR imaging

PURPOSE

To determine whether diffusion-weighted echo-planar magnetic resonance (MR) imaging can help differentiate mucin-producing tumors of the pancreas from other cystic lesions.

MATERIALS AND METHODS

Diffusion-weighted echo-planar 1.5-T MR imaging was performed in patients with mucin-producing tumor (n = 15), pseudocyst (n = 15), or serous microcystic tumor (n = 2). Images were obtained with diffusion-sensitizing gradients of 30 and 300 sec/mm2. The apparent diffusion coefficient (ADC) was calculated.

RESULTS

At 30 sec/mm2, all cystic lesions had very high signal intensity. The dilated main pancreatic duct was depicted in eight patients with mucin-producing tumor and in six with pseudocyst. The mean (+/- standard deviation) ADCs of mucin-producing tumors (2.7 x 10(-3) mm2/sec +/- 0.9 x 10(-3)) and pseudocysts (3.2 x 10(-3) mm2/sec +/- 1.0 x 10(-3) were significantly lower (P < .01) than those of serous cysts or cerebrospinal fluid (5.8 x 10(-3) mm2/sec +/- 2.0 x 10(-3)). At 300 sec/mm2, cysts and the main pancreatic ducts had high signal intensity in cases of mucin-producing tumor, indicative of the presence of mucinous products in both the cystic cavity and the main pancreatic duct. The signal intensity of cystic fluid in pseudocysts was high on diffusion-weighted images, but that of the pancreatic duct was decreased (ADC = 5.1 x 10(-3) mm2/sec +/- 1.7 x 10(-3)).

CONCLUSION

Diffusion-weighted MR imaging can help characterize cystic lesions of the pancreas. Findings-suggestive of viscous fluid in mucin-producing tumors are present on such images.

Hepatic parenchymal perfusion abnormalities after pancreaticobiliary surgery. Evaluation with dynamic helical CT

PURPOSE

To evaluate perfusion abnormalities of the liver after pancreaticobiliary surgery.

MATERIAL AND METHODS

We retrospectively evaluated 128 patients with pancreaticobiliary malignant tumors who had been examined both before and after surgery by means of helical CT of the liver. An infusion of 3 ml/s of 60% nonionic contrast material was followed by helical CT of the liver in a sequential arterial phase, portal venous phase, and equilibrium phase.

RESULTS

Of 128 patients, we followed 97. In 21 patients (22%) we found 47 lesions with perfusion abnormalities that were detected 1-33 months (mean 6.6 months) after the operation. All patients were asymptomatic. The shape of each perfusion abnormality was characterized as geographic (n = 23, 47%), wedge-shaped (n = 21, 45%), or round (n = 3, 8%). The abnormalities were seen in the arterial phase in 46 lesions (98%), in the portal venous phase in 18 lesions (38%), and in the equilibrium phase in 1 lesion (0.2%). In all lesions, the size either decreased spontaneously, or it remained unchanged for more than one year.

CONCLUSION

Perfusion abnormalities of the liver may occur in patients who undergo pancreaticobiliary surgery. This findings should not be confused with hypervascular metastases.

Clinical characteristics of circadian rhythm sleep disorders

From our practice at the sleep disorders clinic in Kohnodai Hospital, National Center of Neurology and Psychiatry (NCNP), we report the clinical characteristics of circadian sleep-wake rhythm disorders. Nearly 90% of circadian rhythm sleep disorders were diagnosed as delayed sleep phase syndrome (DSPS) or as non-24 sleep-wake syndrome (non-24). While DSPS was equally common in males and females, non-24 was more frequently seen in men. It was of psychiatric interest that a considerable number of patients had depressive states in the course of their circadian rhythm sleep disorders. Difficulty in adapting to social life was more severe in patients with non-24 than in those with DSPS.

Continuous measurement of temperature in non-24 hour sleep-wake syndrome

The onset of the low temperature (LT) zone which was defined as a period when the rectal temperature was below its daily mean is a convenient circadian phase marker. In this study, we document three cases of non-24 h sleep-wake syndrome in which identification of the LT zone as an evening circadian phase marker contributed to clinical judgments. We found that the LT zone was correlated well with dim light melatonin onset. Moreover, calculating the LT zone was useful in determining phase position in irregular sleep pattern and in determining the timing of bright light therapy.

Melatonin treatment for circadian rhythm sleep disorders

We administered 1-3 mg melatonin to 11 patients (eight men, three women, aged 16-46 years) with circadian rhythm sleep disorders; nine with delayed sleep phase syndrome and two with non-24-hour sleep-wake syndrome. Sleep logs were recorded throughout the study periods and actigraph and rectal temperature were monitored during treatment periods. Melatonin was administered 1-2 h before the desirable bedtime for expected phase-shifting, or 0.5-1 h before habitual bedtime for gradual advance expecting an hypnotic effect of the melatonin. Melatonin treatments were successful in 6/11 patients. Timing and dose of melatonin administration, together with its pharmacological properties for circadian rhythm sleep disorders, should be further studied.

Trials of bright light exposure and melatonin administration in a patient with non-24 hour sleep-wake syndrome

We report a patient with non-24 h sleep-wake syndrome (non-24) whose free-running sleep-wake cycle was successfully treated with both scheduled bright light exposure and melatonin treatment. In the present study, morning bright light as well as evening melatonin phase-advanced sleep-wake cycles and melatonin rhythm. Both these procedures achieved appropriate entrainment to a 24 h day. However, the patient did not continue morning bright light therapy after the discharge. Rising at appropriate times in the morning for bright light therapy was difficult for him to continue. Melatonin treatment was better tolerated because of its ease of application.

Small cell carcinoma of the stomach: a case report

A case of a gastric small cell carcinoma discovered incidentally by screening ultrasonography is presented. Ultrasonography demonstrated a subcardial metastatic lymph node and multiple hepatic metastatic lesions. Upper GI series and gastroendoscopy revealed a large ulcerated tumor in the cardia of the stomach, and a Borrmann type II tumor, 4 x 2.5 cm, was found in the resected stomach. We describe the radiological findings of the upper GI series, ultrasonography, CT, and gastroendoscopy, and review the literature.

Transjugular intrahepatic portosystemic shunt: initial clinical experience and three-year follow-up

To define the role of transjugular intrahepatic portosystemic shunt (TIPS), we prospectively studied 12 patients undergoing this procedure for variceal bleeding, refractory ascites, and hemorrhagic gastropathy due to portal hypertension. The TIPS creation was successful in 11 patients, and portal pressure immediately decreased an average of 8.3 cm H2O. Esophageal varices improved in six of seven patients, but gastric varices with spleno- or gastro-renal shunt did not change in three of four patients. A hemorrhage from portal hypertensive gastropathy was controlled immediately. Ascites improved in all six patients. Hepatic encephalopathy newly developed in four patients, but was controllable with medical treatment. During the follow-up period (mean, 25 months), shunt dysfunction was evident in eight of 10 patients. Stenosis and occlusion of the shunt were successfully treated by redilatation and/or placement of an additional stent. The cumulative survival rate was 73% at one year and 64% at two years. These results suggest that TIPS is a safe and effective treatment for uncontrollable complications due to portal hypertension, but is not effective for gastric varices with spleno- or gastro-renal shunt. Careful follow-up and shunt revision are necessary for the maintenance of shunt patency.

In vitro and clinical studies of image acquisition in breath-hold MR cholangiopancreatography: single-shot projection technique versus multislice technique

OBJECTIVE

This study was undertaken to compare the in vitro and clinical value of two-dimensional multislice breath-hold MR cholangiopancreatography (MRCP) with a single-shot projection technique using a half-Fourier acquisition single-shot turbo spin-echo sequence.

SUBJECTS AND METHODS

We examined 108 patients with pancreaticobiliary diseases, using breath-hold MRCP and a half-Fourier acquisition single-shot turbo spin-echo sequence on a 1.5-T MR unit with a body phased-array coil. Two data acquisition techniques were employed: multislice acquisition postprocessed by maximum intensity projection (MIP) (multislice technique) and single-shot projection with a thick slice (projection technique). In the multislice technique, nine contiguous slices were obtained with a thickness of 5 mm (acquisition time. 18 sec). In the projection technique, a single slice was obtained with a thickness of 30, 50, or 70 mm (acquisition time. 2 sec). Contrast-to-noise ratio (CNR) between the common bile duct and the liver as well as detectability of normal structures and diseases were compared for these two acquisition techniques. In the multislice technique, source images were also evaluated. ERCP or percutaneous transhepatic cholangiography images were used as the gold standard.

RESULTS

Most of the pancreatic duct and common bile duct was revealed on 54% and 100% of the projection images, respectively, and on 35% and 98% of the MIP images, respectively, CNR was significantly higher with the multislice technique than with the projection technique (p < .01). With the projection technique, CNR decreased as slice thickness increased. Dilatation and occlusion of the pancreaticobiliary tree were equally well revealed by the two imaging techniques. However, abnormalities in the periampullary region and anomalies in the pancreaticobiliary tree were more clearly seen on projection images than on MIP images (p < .05). Stones in the common bile duct, gallbladder, or intrahepatic bile duct were best seen on source images acquired by the multislice technique (83% sensitivity).

CONCLUSION

Because of the absence of misregistration and the speed of image acquisition, breath-hold single-shot MRCP using the projection technique with a slice thickness of 30 or 50 mm consistently revealed the pancreaticobiliary tree and periampullary region with an acceptable CNR. Stones in the bile duct were best seen on the source images acquired by the MIP technique.

Percutaneous microwave coagulation therapy in liver tumors. A 3-year experience

PURPOSE

Percutaneous microwave coagulation therapy (PMCT) is an interventional alternative for inoperable malignant liver tumors. In this paper, we report the results of our 3-year experience of PMCT in order to establish suitable indications for this treatment.

MATERIAL AND METHODS

We studied a total of 27 inoperable liver tumors in 24 patients. Histology of the tumors showed 20 hepatocellular carcinomas (HCCs) (13 well differentiated, 4 moderately differentiated, and 3 poorly differentiated) and 7 metastases. These tumors were treated by PMCT and were followed for 4-40 months (average 18 months). Under US guidance, the tumors were coagulated by microwaves emitted from an electrode. The changes of tumor size after PMCT were evaluated by CT. When the tumors disappeared or were reduced in size after treatment, PMCT was regarded as effective. Complications from PMCT were also evaluated. The patient survival rate was obtained by means of the Kaplan-Meier method.

RESULTS

In tumors of 30 mm or less, treatment response was obtained in 70% of cases, while 55% of tumors larger than 30 mm responded. The tumor became smaller or disappeared in 85% of the well differentiated HCCs, and in 25% of the moderately differentiated HCCs, but none of the poorly differentiated HCCs responded. In metastatic tumors, PMCT was effective in 57% of cases. Slight pain (24%), fever (20%) and subcutaneous hematoma (8%) were experienced immediately after PMCT. In 2 poorly differentiated HCCs, needle tract seeding was observed. No case of liver dysfunction was seen after PMCT. The overall survival rate was 83.1% at 1 year and 68.7% at 2 years.

CONCLUSION

Good therapeutic results were achieved with PMCT in lesions of 30 mm or less, and in well differentiated HCCs.

Cavernous hemangioma of the liver: pathologic correlation with dynamic CT findings

PURPOSE

To correlate the pathologic findings of cavernous hemangiomas with enhancement patterns seen at dynamic computed tomography (CT) performed after injection of contrast material.

MATERIALS AND METHODS

Sixteen patients underwent dynamic CT followed by hepatectomy. Resected specimens of 16 cavernous hemangiomas, which ranged from 2 to 15 cm in diameter, were obtained. The average size of vascular spaces in the histologic specimen was correlated with their appearance on dynamic CT scans.

RESULTS

In 11 tumors, characteristic progressive fill-in after peripheral contrast enhancement was seen (type 1). In type 1 tumors, three zones were noted within the tumor: areas of peripheral puddling in the arterial-dominant phase, areas of gradual fill-in, and areas of no or minimal enhancement. Vascular spaces in areas of peripheral global enhancement were significantly smaller than those in areas of gradual fill-in (P = .03). In areas of no or minimal enhancement, extensive scar tissue (n = 9) or cystic cavity (n = 3) was seen. In three hemangiomas smaller than 3 cm, enhancement occurred diffusely in the arterial-dominant phase and vascular space was small (type 2). In two tumors, enhancement was seen only in the periphery of the tumor (type 3), and the majority of tumor was occupied by the cystic cavity or scar tissue.

CONCLUSION

Dynamic enhancement patterns of cavernous hemangiomas are related to the collective size of their constituent vascular spaces.

Gadolinium-enhanced breath-hold three-dimensional MR angiography of the portal vein: value of the magnetization-prepared rapid acquisition gradient-echo sequence

The authors evaluated magnetic resonance (MR) angiography of the portal vein performed with a breath-hold, gadolinium-enhanced, magnetization-prepared rapid acquisition gradient-echo sequence in five volunteers and 24 patients. The main portal vein and its branches and the liver were depicted clearly in all images. The hepatic vein was clearly depicted in 21 of the 24 patients. MR angiography performed with this sequence allowed high-quality imaging of the portal and hepatic veins.

Multiple-phase helical CT of the liver for detecting small hepatomas in patients with liver cirrhosis: contrast-injection protocol and optimal timing

OBJECTIVE

Helical CT scanners allow multiple-phase sequential scans of the entire liver to be obtained during a single bolus injection of contrast material. The purpose of this study was to compare two injection protocols and to establish timing that would optimize detection of hepatomas less than 3 cm in diameter.

SUBJECTS AND METHODS

Triple-phase helical CT of the liver was evaluated in 217 patients who had liver cirrhosis and were referred for known or suspected hepatomas. Proof of individual neoplasms was based on biopsy results, surgical findings, or findings of other imaging studies. Sixty percent nonionic contrast material, infused at 2 or 4 ml/sec, was followed by sequential arterial-phase, portal-venous phase, and equilibrium-phase helical scans of the liver. Aortic and hepatic enhancement curves were constructed by measuring CT attenuation. The CT attenuation values of individual tumor lesions were also measured. We compared the degree of enhancement of normal structures and tumors obtained with four scan protocols (injection at 2 ml/sec with a 30-sec scan delay [n = 54], injection at 2 ml/sec with a 35-sec scan delay [n = 47], injection at 4 ml/sec with a 20-sec scan delay [n = 56], and injection at 4 ml/sec with a 25-sec scan delay [n = 60] and determined the optimal injection protocol and timing for CT acquisition.

RESULTS

Peak aortic and hepatic enhancement was obtained earlier with the 4-ml/sec protocol (at 24 sec and 61 sec versus 36 sec and 90 sec for the 2-ml/sec protocol). The peak attenuation value of the aorta was higher with the 4-ml/sec protocol (330 H versus 186 H for the 2-ml/sec protocol). However, peak hepatic attenuation was similar for both protocols (98 H for the 4-ml/sec protocol versus 92 H for the 2-ml/sec protocol). Liver-tumor contrast was highest in the arterial phase with both protocols. The next highest contrast was obtained during the equilibrium phase. Liver-tumor contrast in the portal-venous phase was significantly lower than that in the other two phases. Tumor enhancement was significantly higher in scans obtained using the 4-ml/sec protocol with a delay time of 25 sec than those obtained with a delay time of 20 sec. In 109 hepatomas, 35 tumors were only seen or were most conspicuous during the arterial phase, four tumors were most conspicuous during the equilibrium phase, and one tumor was most conspicuous during the portal-venous phase.

CONCLUSION

Arterial-phase helical CT of the liver after 4-ml/sec injection of contrast material significantly improves detection of hepatomas less than 3 cm in diameter when performed in addition to delayed scanning. Portal-venous phase helical CT is of limited value in detecting small hepatomas.

Small hepatocellular carcinoma in patients with chronic liver damage: prospective comparison of detection with dynamic MR imaging and helical CT of the whole liver

PURPOSE

To compare contrast material-enhanced dynamic magnetic resonance (MR) imaging with helical computed tomography (CT) for the detection of small hepatocellular carcinoma (HCC) in patients with chronic liver damage.

MATERIALS AND METHODS

Fifty patients with chronic hepatitis or liver cirrhosis underwent dynamic contrast-enhanced fast low-angle shot MR imaging and multiple-phase helical CT. Arterial, portal-venous, and delayed-phase images were compared. Diagnostic ability with both techniques was evaluated by means of receiver operating characteristic (ROC) analysis; images in patients with (n = 27) and those without (n = 15) HCC in whom the same anatomic levels were available for both examinations were assessed. Seventy-two lesions were evaluated, and tumor diameter ranged from 0.5 to 3.0 cm (mean, 1.9 cm).

RESULTS

ROC analysis showed that the arterial-phase images obtained with both techniques allowed better detection of HCC. Diagnostic ability was significantly better with arterial-phase MR imaging (mean area under the ROC curve [Az] = 0.96) than arterial-phase CT (Az = 0.87) or with images from any other phase (P < .05). For the delayed phase, diagnostic capability was significantly better with CT (Az = 0.84) than with MR imaging (Az = 0.77) (P < .05).

CONCLUSION

Arterial-phase dynamic MR imaging is superior to helical CT for the detection of HCC in patients with chronic liver damage.

MR cholangiopancreatography using HASTE (half-Fourier acquisition single-shot turbo spin-echo) sequences

OBJECTIVE

Images of breath-hold MR cholangiopancreatography (MRCP) using HASTE (half-Fourier acquisition single-shot turbo spin-echo) sequences were taken in healthy volunteers. The technique was then evaluated as a noninvasive alternative to direct cholangiopancreatography in patients with pancreaticobiliary diseases.

SUBJECTS AND METHODS

Forty healthy volunteers and 56 patients with various pancreaticobiliary diseases were examined by MRCP using HASTE with 128 echo train lengths on a 1.5-T MR unit. A body phased-array coll was used for data collection. Imaging times were 2 sec for the single-slice technique with a 20-mm slice thickness and 18 sec for sequential acquisition by the multislice technique with a 5-mm slice thickness (effective TE, 87 msec). We used the healthy volunteers to determine our ability to detect normal structures. The results obtained by HASTE for both patient groups were correlated with imaging by percutaneous transhepatic cholangiography or endoscopic retrograde cholangiopancreatography.

RESULTS

In all healthy volunteers, HASTE-MRCP showed both the common bile duct and the main pancreatic duct. Cystic ducts were visualized in 88% of these volunteers by HASTE-MRCP, and branches of pancreatic ducts were visualized in 75% by HASTE-MRCP. The diameter and length of dilated or stenotic ducts seen on HASTE-MRCP were correlated with percutaneous transhepatic cholangiography or endoscopic retrograde cholangiopancreatography images in 56 diseased patients. Not only the position of stenosis or dilatation but also the distal portion of the stenosis was visualized by HASTE-MRCP.

CONCLUSION

Breath-hold HASTE-MRCP with a phased-array multicoil consistently allows for high-quality images of both normal and diseased pancreaticobiliary tracts. This technique can be used as a noninvasive screening method for pancreaticobiliary diseases in the majority of patients.

Detection of pseudocapsule of renal cell carcinoma with MR imaging and CT

OBJECTIVE

A pseudocapsule surrounding a renal cell carcinoma is a pathologic feature seen frequently in the early stages of this disease. Partial nephrectomy or simple enucleation may be indicated when a pseudocapsule is detected. The purpose of this study is to analyze the roles of MR imaging and CT in showing the pseudocapsule in renal cell carcinomas.

SUBJECTS AND METHODS

MR imaging and CT appearances of the kidneys in 52 patients with 54 renal cell carcinomas--and 40 patients with 45 other renal masses for comparison--were prospectively analyzed and correlated with pathologic results. The frequency of a pseudocapsule in renal cell carcinomas and in various renal tumors was analyzed. We compared the detectability of a pseudocapsule in renal cell carcinomas with MR imaging on T1-weighted spin-echo, T2-weighted spin-echo, and contrast-enhanced T1-weighted spin-echo sequences, and on contrast-enhanced CT.

RESULTS

At pathologic evaluation, a pseudocapsule was seen in 66% (19 of 29) of tumors 4 cm or less in diameter and in 28% (7 or 25) of tumors larger than 4 cm in diameter. All tumors with a pseudocapsule were low histologic grade. Large renal cell carcinomas and other tumors appeared expansile but not encapsulated. A rim corresponding to the pseudocapsule was seen around the tumor in seven lesions on T1-weighted images, 26 lesions on T2-weighted images, and 11 lesions on postcontrast T1-weighted images. T2-weighted imaging was the most sensitive technique for visualization of the pseudocapsule (sensitivity, 68%; specificity, 91%). All pseudocapsules detected on T1-weighted images or postcontrast T1-weighted images could be detected on T2-weighted images. With postcontrast images, enhancement of the pseudocapsule resulted in poor contrast relative to the surrounding tissue. At contrast-enhanced CT, the pseudocapsule was not visible in any tumors. In all MR imaging sequences and in CT, a pseudocapsule were not found in other pathologic conditions except oncocytoma.

CONCLUSION

A pseudocapsule was seen in 66% of renal cell carcinomas 4 cm in diameter or smaller. T2-weighted MR imaging is the most sensitive technique for showing this feature.