Predicting Peak Productivity in Urologic Medicare Practice via Work-Relative Value Units

OBJECTIVE

To explore factors associated with productivity in urologic practice. Work-relative value units (wRVUs), the basis for Center for Medicare & Medicaid Services (CMS) and private payer reimbursements, commonly serve to estimate physician productivity. Limited data describes which practice factors predict increased wRVU productivity.

METHODS

The 2017 and 2018 CMS databases were retrospectively queried for urologic Medicare provider demographics and procedural/service details. Medical school graduation year was used to estimate years in practice and generation (Millennial, Gen X, Baby Boomer, or Post-War). Treated patients' demographics were obtained. Adjusted and unadjusted linear mixed models were performed to predict wRVU production.

RESULTS

Included were 6773 Medicare-participating urologists across the United States. Millennials produced 1115 wRVUs per year, while Gen X and Baby Boomers produced significantly more (1997 and 2104, respectively, P <.01). Post-War urologists produced numerically more (1287, P = .88). In adjusted analyses, predictors of Medicare wRVU productivity included female and pelvic medicine and reconstructive surgery (exponentiated beta estimate (β) 1.46, 95% CI 1.32-1.60), men's health (β 1.22, 95% CI 1.13-1.32), and oncologic subspecialization (β 1.08, 95% CI 1.02-1.14), female gender (β 0.87, 95% CI 0.82-0.92), wRVUs generated from inpatient procedures (β 1.08, 95% CI 1.06-1.09) and office visits (β 0.88, 95% CI 0.87-0.89), and the level of education (β 1.10, 95% CI 1.07-1.14) and percent impoverished patients (β 0.85, 95% CI 0.83-0.88) in provider's practice zip code.

CONCLUSION

Urologic experience, specialization, demographics, practice patterns, and patient demographics are significantly associated with wRVU productivity in Medicare settings. Further work should incorporate quality metrics into wRVUs and ensure patient demographics do not affect reimbursement.

Outcomes for Arthroplasties in Military Health: A Retrospective Analysis of Direct Versus Purchased Care

INTRODUCTION

The Department of Defense is reforming the military health system where surgeries are increasingly referred from military treatment facilities (MTFs) with direct care to higher-volume civilian hospitals under purchased care. This shift may have implications on the quality and cost of care for TRICARE beneficiaries. This study examined the impact of care source and surgical volume on perioperative outcomes and cost of total hip arthroplasties (THAs) and total knee arthroplasties (TKAs).

MATERIALS AND METHODS

We examined TRICARE claims for patients who underwent THA or TKA between 2006 and 2019. The 30-day readmissions, complications, and costs between direct and purchased care were evaluated using the logistic regression model for surgical outcomes and generalized linear models for cost.

RESULTS

We included 71,785 TKA and THA procedures. 11,013 (15.3%) were performed in direct care. They had higher odds of readmissions (odds ratio, OR 1.29 [95% CI, 1.12-1.50]; P < 0.001) but fewer complications (OR 0.83 [95% CI, 0.75-0.93]; P = 0.002). Within direct care, lower-volume facilities had more complications (OR 1.27 [95% CI, 1.01-1.61]; P = 0.05). Costs for index surgeries were significantly higher at MTFs $26,022 (95% CI, $23,393-$28,948) vs. $20,207 ($19,339-$21,113). Simulating transfer of care to very high-volume MTFs, estimated cost savings were $4,370/patient and $20,229,819 (95% CI, $17,406,971-$25,713,571) in total.

CONCLUSIONS

This study found that MTFs are associated with lower odds of complications, higher odds of readmission, and higher costs for THA and TKA compared to purchased care facilities. These findings mean that care in the direct setting is adequate and consolidating care at higher-volume MTFs may reduce health care costs.

Flavin Mononucleotide-Dependent l-Lactate Dehydrogenases: Expanding the Toolbox of Enzymes for l-Lactate Biosensors

The development of L-lactate biosensors has been hampered in recent years by the lack of availability and knowledge about a wider range and diversity of L-lactate-oxidizing enzymes that can be used as bioelements in these sensors. For decades, L-lactate oxidase of Aerococcus viridans (AvLOx) has been used almost exclusively in the field of L-lactate biosensor development and has achieved somewhat like a monopoly status as a biocatalyst for these applications. Studies on other L-lactate-oxidizing enzymes are sparse and are often missing biochemical data. In this work, we made use of the vast amount of sequence information that is currently available on protein databases to investigate the naturally occurring diversity of L-lactate-utilizing enzymes of the flavin mononucleotide (FMN)-dependent α-hydroxy acid oxidoreductase (HAOx) family. We identified the HAOx sequence space specific for L-lactate oxidation and additionally discovered a not-yet described class of soluble and FMN-dependent L-lactate dehydrogenases, which are promising for the construction of second-generation biosensors or other biotechnological applications. Our work paves the way for new studies on α-hydroxy acid biosensors and proves that there is more to the HAOx family than AvLOx.

Trends in Surgical Volume in the Military Health System-A Potential Threat to Mission Readiness

INTRODUCTION

The Military Health System (MHS) is tasked with a dual mission both to provide medical services for covered patients and to ensure that its active duty medical personnel maintain readiness for deployment. Knowledge, skills, and attitudes (KSA) is a metric evaluating the transferrable skills incorporated into a given surgery or medical procedure that are most relevant for surgeons deployed to a theatre of war. Procedures carrying a high KSA value are those utilizing skills with high relevance for maintaining deployment readiness. Given ongoing concerns regarding surgical volumes at MTFs and the potential adverse impact on military surgeon mission readiness were high-value surgeries to be lost to the civilian sector, we evaluated trends in the setting of high-value surgeries for beneficiaries within the MHS.

METHODS

We retrospectively analyzed inpatient admissions data from MTFs and TRICARE claims data from civilian hospitals, 2005-2019, to identify TRICARE-covered patients covered under "purchased care" (referred to civilian facilities) or receiving "direct care" (undergoing treatment at MTFs) and undergoing seven high-value/high-KSA surgeries: colectomy, pancreatectomy, hepatectomy, open carotid endarterectomy, abdominal aortic aneurysm (AAA) repair, esophagectomy, and coronary artery bypass grafting (CABG). Overall and procedure-specific counts were captured, MTFs were categorized into quartiles by volume, and independence between trends was tested with a Cochran-Armitage test, hypothesizing that the proportion of cases referred for purchased care was increasing.

RESULTS

We captured 292,411 cases, including 7,653 pancreatectomies, 4,177 hepatectomies, 3,815 esophagectomies, 112,684 colectomies, 92,161 CABGs, 26,893 AAA repairs, and 45,028 carotid endarterectomies. The majority of cases included were referred for purchased care (90.3%), with the proportion of cases referred increasing over the study period (P < .01). By procedure, all cases except AAA repairs were increasingly referred for treatment over the study period (all P < .01, except esophagectomy P = .04). On examining volume, we found that even the highest-volume-quartile MTFs performed a median of less than one esophagectomy, hepatectomy, or pancreatectomy per month. The only included procedure performed once a month or more at the majority of MTFs was CABG.

CONCLUSION

On examining volume and referral trends for high-value surgeries within the MHS, we found low surgical volumes at the vast majority of included MTFs and an increasing proportion of cases referred to civilian hospitals over the last 15 years. Our findings illustrate missed opportunities for maintaining the mission readiness of military surgical personnel. Prioritizing the recapture of lost surgical volume may improve the surgical teams' mission readiness.

Prehabilitation in patients undergoing colorectal surgery fails to confer reduction in overall morbidity: Results of a single-center, single-blinded, randomized controlled trial

Objective

Patients undergoing major surgery are prone to a functional decline due to the impairment of muscle, cardiorespiratory and neurological function as a response to surgical stress. Currently, there are solely weak recommendations in the ERAS protocol regarding the role of preoperative physical activity and prehabilitation in patients undergoing colorectal surgery. Studies in heterogenous cohorts showed contradictory results regarding the impact of prehabilitation on the reduction of postoperative complications. This randomized controlled trial assesses the impact of prehabilitation on postoperative complications in patients undergoing colorectal surgery within an ERAS protocol.

Methods

Between July 2016 and June 2019, a single-center, single-blinded , randomized controlled trial designed to test whether physiotherapeutic prehabilitation vs. normal physical activities prior to colorectal surgery may decrease morbidity within a stringent ERAS protocol was carried out. The primary endpoint was postoperative complications assessed by Comprehensive Complications Index (CCI®). Primary and secondary endpoints for both groups were analyzed and compared.

Results

A total of 107 patients (54 in the pERACS and 53 in the control cohort) were included in the study and randomized. Dropout rate was 4.5% (n = 5). Mean age (SD) in the control cohort was 65 (29–86) and 66 (24–90) years in pERACS cohort. The pERACS cohort contained more female patients (40% vs. 55%, p = 0.123) and a higher percentage of colorectal adenocarcinoma (32% vs. 23%, p = 0.384) although not significant. Almost all patients underwent minimally invasive surgery in both cohorts (96% vs 98%, p = 1.000). There was no between-cohort difference in the primary outcome measure 30-day Comprehensive Complications Index (15 [0 – 49] vs. 18 [0 – 43], p = 0.059). Secondary outcome as complications assessed according to Clavien-Dindo, length of hospital stay, reoperation rate and mortality showed no difference between both cohorts.

Conclusion

Routine physiotherapeutic prehabilitation cannot be recommended for patients undergoing colorectal surgery within an ERAS protocol (Grade A recommendation). To eliminate other confounders like geographical difference or difference in surgical technique, further multicenter RCTs are needed.

Racial differences in the treatment and outcomes for prostate cancer in Massachusetts

BACKGROUND

Massachusetts is a northeastern state with universally mandated health insurance since 2006. Although Black men have generally worse prostate cancer outcomes, emerging data suggest that they may experience equivalent outcomes within a fully insured system. In this setting, the authors analyzed treatments and outcomes of non-Hispanic White and Black men in Massachusetts.

METHODS

White and Black men who were 20 years old or older and had been diagnosed with localized intermediate- or high-risk nonmetastatic prostate cancer in 2004-2015 were identified in the Massachusetts Cancer Registry. Adjusted logistic regression models were used to assess predictors of definitive therapy. Adjusted and unadjusted survival models compared cancer-specific mortality. Interaction terms were then used to assess whether the effect of race varied between counties.

RESULTS

A total of 20,856 men were identified. Of these, 19,287 (92.5%) were White. There were significant county-level differences in the odds of receiving definitive therapy and survival. Survival was worse for those with high-risk cancer (adjusted hazard ratio [HR], 1.50; 95% CI, 1.4-1.60) and those with public insurance (adjusted HR for Medicaid, 1.69; 95% CI, 1.38-2.07; adjusted HR for Medicare, 1.2; 95% CI, 1.14-1.35). Black men were less likely to receive definitive therapy (adjusted odds ratio, 0.78; 95% CI, 0.74-0.83) but had a 17% lower cancer-specific mortality (adjusted HR, 0.83; 95% CI, 0.7-0.99).

CONCLUSIONS

Despite lower odds of definitive treatment, Black men experience decreased cancer-specific mortality in comparison with White men in Massachusetts. These data support the growing body of research showing that Black men may achieve outcomes equivalent to or even better than those of White men within the context of a well-insured population.

LAY SUMMARY

There is a growing body of evidence showing that the excess risk of death among Black men with prostate cancer may be caused by disparities in access to care, with few or no disparities seen in universally insured health systems such as the Veterans Affairs and US Military Health System. Therefore, the authors sought to assess racial disparities in prostate cancer in Massachusetts, which was the earliest US state to mandate universal insurance coverage (in 2006). Despite lower odds of definitive treatment, Black men with prostate cancer experience reduced cancer-specific mortality in comparison with White men in Massachusetts. These data support the growing body of research showing that Black men may achieve outcomes equivalent to or even better than those of White men within the context of a well-insured population.

Comparison of comorbidity indices for prediction of morbidity and mortality after major surgical procedures

BACKGROUND

Assessing perioperative risk is essential for surgical decision-making. Our study compares the accuracy of comorbidity indices to predict morbidity and mortality.

METHODS

Analyzing the National Surgical Quality Improvement Program, 16 major procedures were identified and American Society of Anesthesiologists (ASA), Charlson Comorbidity Index and modified Frailty Index were calculated. We fit models with each comorbidity index for prediction of morbidity, mortality, and prolonged length of stay (pLOS). Decision Curve Analysis determined the effectiveness of each model.

RESULTS

Of 650,437 patients, 11.7%, 6.0%, 17.0% and 0.75% experienced any, major complication, pLOS, and mortality, respectively. Each index was an independent predictor of morbidity, mortality, and pLOS (p < 0.05). While the indices performed similarly for morbidity and pLOS, ASA demonstrated greater net benefit for threshold probabilities of 1-5% for mortality.

CONCLUSIONS

Models including readily available factors (age, sex) already provide a robust estimation of perioperative morbidity and mortality, even without considering comorbidity indices. All comorbidity indices show similar accuracy for prediction of morbidity and pLOS, while ASA, the score easiest to calculate, performs best in prediction of mortality.

The Relationship Between Health Literacy and Nonrecommended Cancer Screening

INTRODUCTION

Health literacy affects how patients behave within the healthcare system. Overutilization of screening procedures inconsistent with the U.S. Preventive Services Task Force guidelines contributes to the high cost of health care. The authors hypothesize that higher health literacy supports guideline-concordant screening. This study assesses the effect of health literacy on nonrecommended prostate, breast, and cervical cancer screening in patients older than the recommended screening age limit.

METHODS

The 2016 Behavioral Risk Factor Surveillance System included health literacy modules. Respondents self-reported their ability to obtain and understand health information, resulting in 4 health literacy rankings. The authors calculated the population-weighted proportion of respondents in each health literacy category who underwent screening past the Task Force‒recommended age limit. The ORs of nonrecommended screening for each malignancy were calculated, with low health literacy as the ref category.

RESULTS

Individuals with higher health literacy underwent more nonrecommended screening. Nonrecommended prostate cancer screening was performed in 27.4% (95% CI=23.7%, 31.4%) and 47.7% (95% CI=44.1%, 51.3%) of respondents with low and high health literacy, respectively (p<0.001). Nonrecommended breast cancer screening was performed in 46.8% (95% CI=42.6%, 51.1%) and 67.7% (95% CI=64.2%, 71.1%) of respondents with low and high health literacy, respectively (p=0.002). Nonrecommended cervical cancer screening was performed in 33.8% (95% CI=31.1%, 36.5%) and 48.4% (95% CI=46.3%, 50.5%) of respondents with low and high health literacy, respectively (p<0.001). Individuals with high health literacy were significantly more likely than those with low health literacy to screen against the recommendations for prostate (OR=1.73, 95% CI=1.34, 2.23, p<0.001), cervical (OR=1.533, 95% CI=1.31, 1.80, p<0.001), and breast (OR=8.213, 95% CI=4.90, 13.76, p<0.001) cancer.

CONCLUSIONS

Higher health literacy correlates with increased rates of screening beyond the recommended age, contrary to the study hypothesis. Breast cancer demonstrated the highest rates of nonrecommended screening.

Is the current referral trend a threat to the Military Health System? Perioperative outcomes and costs after colorectal surgery in the Military Health System versus civilian facilities

BACKGROUND

TRICARE military beneficiaries are increasingly referred for major surgeries to civilian hospitals under "purchased care." This loss of volume may have a negative impact on the readiness of surgeons working in the "direct-care" setting at military treatment facilities and has important implications under the volume-quality paradigm. The objective of this study is to assess the impact of care source (direct versus purchased) and surgical volume on perioperative outcomes and costs of colorectal surgeries.

METHODS

We examined TRICARE claims and medical records for 18- to 64-year-old patients undergoing major colorectal surgery from 2006 to 2015. We used a retrospective, weighted estimating equations analysis to assess differences in 30-day outcomes (mortality, readmissions, and major or minor complications) and costs (index and total including 30-day postsurgery) for colorectal surgery patients between purchased and direct care.

RESULTS

We included 20,317 patients, with 24.8% undergoing direct-care surgery. Mean length of stay was 7.6 vs 7.7 days for direct and purchased care, respectively (P = .24). Adjusted 30-day odds between care settings revealed that although hospital readmissions (odds ratio 1.40) were significantly higher in direct care, overall complications (odds ratio 1.05) were similar between the 2 settings. However, mean total costs between direct and purchased care differed ($55,833 vs $30,513, respectively). Within direct care, mean total costs ($50,341; 95% confidence interval $41,509-$59,173) were lower at very high-volume facilities compared to other facilities ($54,869; 95% confidence interval $47,822-$61,916).

CONCLUSION

Direct care was associated with higher odds of readmissions, similar overall complications, and higher costs. Contrary to common assumptions regarding volume and quality, higher volume in the direct-care setting was not associated with fewer complications.

Contemporary Treatment Patterns for Non-muscle-invasive Bladder Cancer: Has the Use of Radical Cystectomy Changed in the BCG Shortage Era?

OBJECTIVE

To examine recent treatment trends for non-muscle-invasive bladder cancer (NMIBC), and specifically, to assess whether there was a change in use radical cystectomy (RC) between 2008 and 2015 using data from the Surveillance, Epidemiology, and End Results database.

METHODS

We identified patients presenting with high-grade T1 (T1HG) NMIBC at diagnosis during the study period. Treatment was dichotomized into "RC" and "local treatment" (which included transurethral resection and intravesical therapies). We then employed multivariable logistic regression models to assess the odds of undergoing RC across the study period. Additionally we examined the rates of RC for T1HG NMIBC during the period of BCG-shortage, defined as 2012-2015.

RESULTS

We identified 21,817 individuals diagnosed with T1HG bladder cancer during the study period. The majority of patients underwent local treatment (94.5%). During the shortage period, the rate of RC for T1HG NMIBC was significantly lower compared to the preshortage era (5.1% vs 5.9%, P = .007). Across the study period, the utilization of RC for T1HG NMIBC decreased significantly (odds ratio 0.99 per quarter, 95% confidence interval 0.98-0.99, P = .017).

CONCLUSION

In our cohort of patients diagnosed with T1HG bladder cancer, we found a significant decrease in the use of radical cystectomy across the study period. Contrary to the hypothesis of increasing rates of RC in the face of BCG shortage, the rate of RC was significantly higher in the pre-shortage era. Further examination of NMIBC treatment patterns will be necessary to assess the impact of BCG availability on therapeutic pathways and oncologic outcomes in patients with high-grade NMIBC.

Risk of Dementia and Depression in Young and Middle-aged Men Presenting with Nonmetastatic Prostate Cancer Treated with Androgen Deprivation Therapy

BACKGROUND

Previous studies have found an association between androgen deprivation therapy (ADT) and an increased risk of dementia and depression in elderly men. This association remains controversial, and little is known about the effects of ADT in younger men.

OBJECTIVE

To examine the association between the receipt of ADT and these outcomes in young men aged 40-64 yr presenting with nonmetastatic prostate cancer (PCa).

DESIGN, SETTING, AND PARTICIPANTS

For this observational study, we identified 9117 men aged 40-64 yr diagnosed with localized PCa between 2007 and 2014, without a pre-existing neurocognitive diagnosis, using the TRICARE military database.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Kaplan-Meier curves were fitted to compare ADT versus no ADT. We also performed a subgroup analysis in patients undergoing ADT for ≥12 mo. The association between ADT and new-onset dementia or depression was evaluated using inverse-probability-of treatment-weight-adjusted Cox proportional hazards regression analysis.

RESULTS AND LIMITATIONS

Patients receiving ADT had a significantly higher incidence of depression (30.2 vs 15.8 per 1000 person years) and dementia (17.9 vs 7.5 per 1000 person years). The risk of developing either outcome was higher in the ADT cohort (depression: hazard ratio [HR] 2.07, p < 0.001; dementia: HR 1.70, p = 0.052). Additionally, there was a dose-response relationship between the duration of ADT and either outcome.

CONCLUSIONS

In our cohort of young men with PCa, the receipt of ADT was associated with an increased risk of developing dementia and depression. Long-term use of ADT was associated with the highest risk of neurocognitive outcomes.

PATIENT SUMMARY

In this study, we looked at the risk of dementia and depression in patients <65 yr of age undergoing androgen deprivation therapy (ADT) for prostate cancer. We found that these patients had a higher risk of dementia and depression than those who did not undergo ADT.

Impact of Index Surgical Care Setting on Perioperative Outcomes and Cost Following Penile Prosthesis Surgery

BACKGROUND

Penile prosthesis surgery has witnessed a migration from the inpatient to ambulatory surgical care setting. However, little is known about the cost savings afforded by this change in care setting and whether or not these savings come at the expense of worse perioperative outcomes.

AIM

The aim of this study was to identify predictors of index penile prosthesis (PP) surgery care setting, and whether ambulatory vs inpatient surgery is associated with comparable perioperative outcomes and costs.

METHODS

This was a retrospective cohort study using all-payer claims data from the 2014 Healthcare Cost and Utilization Project State Databases from Florida and New York. Patient demographics, regional data, total charges (converted to costs), and 30-day revisit rates were abstracted for all patients undergoing index placement of an inflatable or malleable PP. Multivariable logistic and linear regression adjusted for facility clustering was utilized.

OUTCOMES

The outcomes were index surgical and 30-day postoperative costs, as well as 30-day revisit rates.

RESULTS

Of the 1,790 patients undergoing an index surgery, 394 (22.0%) received care in the inpatient setting compared to 1,396 (78.0%) in the ambulatory setting. Adjusted index procedural ($9,319.66 vs $ 10,191.35; P < .001) and 30-day acute care costs ($9,461.74 vs $10,159.42; P < .001) were lower in the ambulatory setting. The underinsured experienced lower odds of receiving surgery in the ambulatory setting (Medicaid vs private: odds ratio [OR] 0.19; 95% CI 0.06-0.55; P < .001). There was no difference in risk-adjusted odds of experiencing a 30-day revisit between patients undergoing surgery in the ambulatory vs inpatient settings (OR 1.31; 95% CI 0.78-2.21; P = .3).

CLINICAL TRANSLATION

Ambulatory PP surgery confers significant cost savings and is associated with comparable perioperative outcomes relative to inpatient-based surgery.

CONCLUSIONS

Both clinical and nonclinical factors predict the care setting of index PP surgery. Notably, underinsured patients experienced lower odds of undergoing ambulatory surgery. Ambulatory surgery was less costly with similar 30-day revisit rates relative to inpatient-based care. Berger A, Friedlander DF, Herzog P, et al. Impact of Index Surgical Care Setting on Perioperative Outcomes and Cost Following Penile Prosthesis Surgery. J Sex Med 2019;16:1451-1458.

Measurement of relative lung perfusion with electrical impedance and positron emission tomography: an experimental comparative study in pigs

BACKGROUND

Electrical impedance tomography (EIT) with indicator dilution may be clinically useful to measure relative lung perfusion, but there is limited information on the performance of this technique.

METHODS

Thirteen pigs (50-66 kg) were anaesthetised and mechanically ventilated. Sequential changes in ventilation were made: (i) right-lung ventilation with left-lung collapse, (ii) two-lung ventilation with optimised PEEP, (iii) two-lung ventilation with zero PEEP after saline lung lavage, (iv) two-lung ventilation with maximum PEEP (20/25 cm H₂O to achieve peak airway pressure 45 cm H₂O), and (v) two-lung ventilation under unilateral pulmonary artery occlusion. Relative lung perfusion was assessed with EIT and central venous injection of saline 3%, 5%, and 10% (10 ml) during breath holds. Relative perfusion was determined by positron emission tomography (PET) using ⁶⁸Gallium-labelled microspheres. EIT and PET were compared in eight regions of equal ventro-dorsal height (right, left, ventral, mid-ventral, mid-dorsal, and dorsal), and directional changes in regional perfusion were determined.

RESULTS

Differences between methods were relatively small (95% of values differed by less than 8.7%, 8.9%, and 9.5% for saline 10%, 5%, and 3%, respectively). Compared with PET, EIT underestimated relative perfusion in dependent, and overestimated it in non-dependent, regions. EIT and PET detected the same direction of change in relative lung perfusion in 68.9-95.9% of measurements.

CONCLUSIONS

The agreement between EIT and PET for measuring and tracking changes of relative lung perfusion was satisfactory for clinical purposes. Indicator-based EIT may prove useful for measuring pulmonary perfusion at bedside.

MRI predictors of clinical success in MR-guided focused ultrasound (MRgFUS) treatments of uterine fibroids: results from a single centre

OBJECTIVES

To assess the technical and clinical results of MRgFUS treatment and factors affecting clinical treatment success.

MATERIALS AND METHODS

A total of 252 women (mean age, 42.1 ± 6.9 years) with uterine fibroids underwent MRgFUS. All patients underwent MRI before treatment. Results were evaluated with respect to post-treatment nonperfused volume (NPV), symptom severity score (SSS), reintervention rate, pregnancy and safety data.

RESULTS

NPV ratio was significantly higher in fibroids characterized by low signal intensity in contrast-enhanced T1-weighted fat saturated MR images and in fibroids distant from the spine (>3 cm). NPV ratio was lower in fibroids with septations, with subserosal component and in skin-distant fibroids (p < 0.001). NPV ratio was highly correlated with clinical success: NPV of more than 80 % resulted in clinical success in more than 80 % of patients. Reintervention rate was 12.7 % (mean follow-up time, 19.4 ± 8 months; range, 3-38). Expulsion of fibroids (21 %) was significantly correlated with a high clinical success rate. No severe adverse events were reported.

CONCLUSIONS

Adequate patient selection and correct treatment techniques, based on the learning curve of this technology, combined with technical advances of the system, lead to higher clinical success rates with low complications rate, comparable to other uterine-sparing treatment options.

KEY POINTS

• MRgFUS appears to be a valid alternative to other uterus-preserving therapies • Patient selection is a significant factor in achieving high NPV ratios • MRI screening parameters correlate with the amount of fibroid ablation in MRgFUS • NPV results of more than 80 % correlate with higher clinical success rates.

Strahlendosis und Möglichkeiten zur Dosisreduktion in der Mehrschicht-CT

Since its introduction a few years ago, multidetector row CT (MDCT) has become a widely used diagnostic procedure and has been proven to be a valuable tool for various indications. A major issue using this new modality is the inherent risk of applying increased radiation exposure, when compared to single-slice CT or other imaging modalities.However, MDCT offers some valuable options to save radiation exposure, such as choosing optimized exposure parameters or its superior dose efficiency in comparison to single-slice CT. Multi-phasic examinations should be restricted to indications where definitely necessary. Modern scanners offer intelligent tools for further reduction of radiation dose, such as ECG- or bodyshape-based realtime dose modulation. A new field of applications is the low-dose CT for early detection of diseases. While acquiring thin slices with high spatial resolution, the dose can be reduced to similar values as in conventional radiography, especially when examining under high-contrast conditions. Using all these various options available, radiation exposure can sometimes even be lower than using a conventional single-slice helical CT.

Hochaufgelöste abdominelle Übersichtsangiographie mit einem 16-Detektorzeilen-CT-System Erste Erfahrungen

PURPOSE

Purpose of this study was the implementation of a new abdominal CT angiography protocol on a 16 detector-row CT scanner and the comparison to selective catheter angiography.

METHODS

76 patients with various vascular disorders underwent abdominal CT angiography on a recently developed 16 detector-row CT scanner using submillimeter slice collimation (16 x 0.75 mm). Results were compared with mesenteric and/or hepatic angiography in 17 patients performed during tumor embolization. Opacification was provided using individually tailored contrast application with a test bolus setting. To evaluate the contrast injection protocol density measurements within the vessel lumen were performed.

RESULTS

Diagnostic image quality was achieved in all patients with angiographic comparison (n = 17). Within the hepatic and mesenteric vasculature up to 4th generation vessels could be identified. Compared to selective angiography CT angiography provided equivalent morphologic information up to the detectable vessel generation. With the applied contrast application regimen there were no significant differences in vessel enhancement along the abdominal aorta and iliac arteries.

CONCLUSION

16 detector-row CT enables whole abdominal angiographic studies with submillimeter resolution in a single breath-hold. The improved spatial resolution enables for high quality 3D visualization. Compared to invasive angiography, 16 detector-row CT reveals equivalent morphologic information.

CT-Angiographie der Koronararterien mit einem 16-Mehrzeilen-Spiral-CT Einfluss der räumlichen Auflösung auf die Bildqualität

PURPOSE

To evaluate image quality of coronary CT angiography with retrospectively ECG-gated 16 multi-slice spiral CT (MSCT), reconstructed with 0.75 mm slice thickness for optimal spatial resolution and with 1.3 mm slice thickness, to produce spatial resolution comparable to a 4-MSCT.

MATERIALS AND METHODS

Ten patients underwent coronary CT angiography with a 16-MSCT (Siemens Sensation 16, Forchheim, Germany) with 0.75 mm detector collimation. Raw helical CT data were retrospectively reconstructed using two different settings. Setting A: B20f smooth kernel, axial MPR with 1.3 mm slice thickness and 0.7 mm increment. Setting B: B35f "HeartView" medium-smooth kernel, 0.75 mm slice thickness, 0.5 mm increment. In the axial slices two regions of interest (ROIs) were placed in the area of the aortic root (AR) and more caudal in the area of the left ventricle (LV). Image noise was determined by the standard deviation of the CT numbers.Two readers determined visibility of coronary arteries by standardized maximum intensity projections (MIP) post-processing in left, right anterior and left anterior oblique projection plane from setting A and B. Each projection was rated on a five point rating scale concerning plaque delineation. Points determined for each data set were summed up and used for comparison.

RESULTS

No significant difference between the CT-numbers was found for setting A and B (A: 283.0 in AR/295.9 in LV and B: 282,9 in AR/297.2 in LV; p >0.2). However, the image noise was significantly different for setting A and B (A: 4.46 in AR/1.67 in LV and B: 8.16 in AR/7.38 in LV; p <0.01). Better delineation of the coronary arteries and atherosclerotic lesions could be achieved from MIP projections in setting B compared to setting A.

CONCLUSION

Higher image noise is present in coronary 16-MSCT with thin-slice reconstruction compared to simulated 4-MSCT. However the MIP-reconstructions benefit most from the higher spatial resolution.

Research on energy savings opportunities in university libraries

Purpose

Mechanical systems in library environments are typically designed to run continuously in order to maintain the desired environmental conditions for preservation purposes, often resulting in a high cost in dollars and energy consumption. Altering these conditions through changed HVAC operating schedules is a risk many librarians and institutions are hesitant to take. This study aims to introduce the methodology and early findings of current research into the question of whether energy usage can be significantly reduced in libraries by carefully monitored and risk‐managed shutdowns of air handling units (AHUs) during unoccupied hours in selected spaces without compromising the quality of the preservation environment.

Design/methodology approach

As part of the project, the authors are monitoring up to three air handling units (AHUs) at each of five partner institutions, three of which are university libraries or repositories, as well as the associated collections spaces served by the units.

Findings

Early findings show the potential value of systems shutdowns in various parts of the country, while also identifying regions that are less favorable.

Practical implications

In all cases, the experimentation with and successful implementation of a shutdown schedule, without adversely affecting preservation conditions, was preceded by careful documentation and risk management, as described.

Originality/value

Unlike unilateral HVAC equipment shutdowns and setbacks conducted solely for energy management, with little regard for collections, this risk‐managed and documented approach potentially allows for the reduction of energy usage without placing collections' health at risk.

Primary follicular lymphoma of the duodenum is a distinct mucosal/submucosal variant of follicular lymphoma: a retrospective study of 63 cases

PURPOSE

Small series with limited follow-up have suggested primary follicular lymphoma of the duodenum (FL-D) to be an indolent disease. We report our experience on a large series of patients followed for a median time period of longer than 6 years.

PATIENTS AND METHODS

The study comprised 63 patients with primary FL-D defined as stage I disease. Endoscopy and detailed pathologic work-up was performed at diagnosis and at restaging to monitor the behavior of the neoplastic process.

RESULTS

Histologically, all 63 patients had FL, low grade (1 to 2). Duodenal endosonography demonstrated lesions confined to mucosa/submucosa in 19 of 20 patients. At an overall median follow-up of 77 months (range, 12 to 177 months), only two untreated patients had developed nodal disease, the remaining 61 patients never experienced extrasmall intestinal disease and large cell transformation did not occur at all. Among 24 patients followed by watch and wait strategy, seven showed spontaneous complete regression and 17 had stable disease; radiotherapy resulted in complete regression in all 19 patients; anti-CD20 antibody monotherapy achieved complete regression in four patients and stable disease in one patient. Various chemotherapy protocols in eight patients caused complete regression in all of them, but local relapses occurred in three. No patients required surgery or died of disease.

CONCLUSION

These findings characterize primary FL-D as a remarkably indolent FL variant, which, even left untreated, does not develop tumorous growth, very rarely disseminates (two of 63 patients) and does not transform to high grade disease. A watch and wait approach appears to be the most sensible strategy.

Relevance of correction for rotational targeting error in functional neurosurgery

OBJECTIVE

A prospective study is presented on the amount of targeting error that is due to rotational deviations between the atlas and the stereotactic coordinate system.

MATERIALS AND METHODS

We investigated 14 volunteers with a stereotactic frame fixed to their heads by tight adhesive bands. Sagittal, coronal and axial T2-weighted MRI scans, as well as MPRage sequences, were performed. The anterior and posterior commissures and one additional point on the midline (the septum pellucidum) were determined on the axial T2-weighted images. Bilateral atlas coordinates for the subthalamic nucleus (STN), globus pallidus pars interna (GPi) and nucleus ventralis intermedius (Vim) were transformed to stereotactic frame coordinates, either without correction or by 2-point or 3-point correction. A total of 896 coordinates (x, y, z for the STN, GPi and Vim in both hemispheres) were calculated.

RESULTS

Although the mean differences between the two algorithms (0.24 +/- standard deviation of 0.33 mm) were within the range of system-immanent inaccuracies in MRI-guided stereotaxy, deviations of up to 2.8 mm occurred. No significant correlation was found regarding the amount of rotational angle and the differences in x-, y-, or z-coordinates when 2-point and 3-point transformations were compared.

CONCLUSIONS

The reliability of meticulous trajectory planning might be compromised significantly by using only 2-point-based correction or no calculations at all.

Assessment of radiation exposure on a dual-source computed tomography-scanner performing coronary computed tomography-angiography

OBJECTIVE

The radiation exposure of a dual-source-64-channel multi-detector-computed-tomography-scanner (Somatom-Defintion, Siemens, Germany) was assessed in a phantom-study performing coronary-CT-angiography (CTCA) in comparison to patients' data randomly selected from routine scanning.

METHODS

240 CT-acquisitions of a computed tomography dose index (CTDI)-phantom (PTW, Freiburg, Germany) were performed using a synthetically generated Electrocardiography (ECG)-signal with variable heart rates (30-180 beats per minute (bpm)). 120 measurements were acquired using continuous tube-output; 120 measurements were performed using ECG-synchronized tube-modulation. The pulsing window was set at minimum duration at 65% of the cardiac cycle between 30 and 75 bpm. From 90-180 bpm the pulsing window was set at 30-70% of the cardiac cycle. Automated pitch adaptation was always used. A comparison between phantom CTDI and two patient groups' CTDI corresponding to the two pulsing groups was performed.

RESULTS

Without ECG-tube-modulation CDTI-values were affected by heart-rate-changes resulting in 85.7 mGray (mGy) at 30 and 45 bpm, 65.5 mGy/60 bpm, 54.7 mGy/75 bpm, 46.5 mGy/90 bpm, 34.2 mGy/120 bpm, 27.0 mGy/150 bpm and 22.1 mGy/180 bpm equal to effective doses between 14.5 mSievert (mSv) at 30/45 bpm and 3.6 mSv at 180 bpm. Using ECG-tube-modulation these CTDI-values resulted: 32.6 mGy/30 bpm, 36.6 mGy/45 bpm, 31.4 mGy/60 bpm, 26.8 mGy/75 bpm, 23.7 mGy/90 bpm, 19.4 mGy/120 bpm, 17.2 mGy/150 bpm and 15.6 mGy/180 bpm equal to effective doses between 5.5 mSv at 30 bpm and 2.6 mSv at 180 bpm. Significant CTDI-differences were found between patients with lower/moderate and higher heart rates in comparison to the phantom CTDI-results.

CONCLUSIONS

Dual source CTCA is particularly dose efficient at high heart rates when automated pitch adaptation, especially in combination with ECG-based tube-modulation is used. However in clinical routine scanning for patients with higher heart rates and corresponding enlarged pulsing window a significant different dose resulted.

Chronische Lungenembolie – Radiologische Bildmorphologie und Differenzialdiagnose

In chronic pulmonary embolism branches of the pulmonary arterial tree remain partially or totally occluded. This may lead to pulmonary hypertension with the development of right ventricular hypertrophy as well as structural changes of pulmonary arteries. Imaging of chronic pulmonary embolism should prove vessel occlusions (pulmonary angiography, MSCT, MRI) and reduction of regional lung perfusion (lung scanning, MSCT, MRI). According to current guidelines ventilation-perfusion lung scanning and pulmonary angiography are still recommended as the methods of choice. MSCT and MRI provide technical alternatives which are helpful in differential diagnosis versus other types of pulmonary hypertension. In spite of medical and surgical measures (in rare cases pulmonary thromboendarterectomy) the prognosis of chronic pulmonary embolism remains unfavourable.

Beam hardening artefacts occur in dental implant scans with the NewTom cone beam CT but not with the dental 4-row multidetector CT

OBJECTIVES

The aim of this study was to examine beam hardening artefacts of the NewTom 9000 cone-beam computed tomography (CBCT) device compared with the Philips MX 8000 (4-row multidetector CT (MDCT)).

METHODS

We modified a SawBone skull to become a standardized model for our study. The skull was used for scans with the NewTom 9000 CBCT device and a standard dental multi-detector CT (MDCT) at a comparable reconstruction resolution with a standard Straumann ITI 4.1 mm implant in four implant positions in the maxilla (first permanent premolar in the right maxilla region, second permanent molar in the right maxilla region, first permanent premolar in the left maxilla region and second permanent molar in the left maxilla region). Results were compared with construction data of the dental implant. An image quality assessment of the images from both devices was performed with four experienced physicians and statistically analysed with the two-tailed Wilcoxon test.

RESULTS

Scans with the NewTom 9000 CBCT showed strong beam hardening artefacts in the form of a radiation beam shadow in all reconstructions compared with the MDCT. These imaging artefacts became stronger with greater distance from the centre of the scanned volume. These differences in the imaging quality were proved as significant in a quality evaluation by four experienced physicians (P<0.05).

CONCLUSIONS

Visual spatial resolution of the NewTom 9000 CBCT was less accurate than the Philips MX 8000 MDCT in the imaging of metallic dental implants.

Clinical evaluation of a computer-aided diagnosis (CAD) prototype for the detection of pulmonary embolism

RATIONALE AND OBJECTIVES

To evaluate the performance of a prototype computer-aided diagnosis (CAD) tool using artificial intelligence techniques for the detection of pulmonary embolism (PE) and the possible benefit for general radiologists.

MATERIALS AND METHODS

Forty multidetector row computed tomography datasets (16/64- channel scanner) using 100 kVp, 100 mAs effective/slice, and 1-mm axial reformats in a low-frequency reconstruction kernel were evaluated. A total of 80 mL iodinated contrast material was injected at a flow rate of 5 mL/seconds. Primarily, six general radiologists marked any PE using a commercially available lung evaluation software with simultaneous, automatic processing by CAD in the background. An expert panel consisting of two chest radiologists analyzed all PE marks from the readers and CAD, also searching for additional finding primarily missed by both, forming the ground truth.

RESULTS

The ground truth consisted of 212 emboli. Of these, 65 (31%) were centrally and 147 (69%) were peripherally located. The readers detected 157/212 emboli (74%) leading to a sensitivity of 97% (63/65) for central and 70% (103/147) for peripheral emboli with 9 false-positive findings. CAD detected 168/212 emboli (79%), reaching a sensitivity of 74% for central (48/65) and 82%(120/147) for peripheral emboli. A total of 154 CAD candidates were considered as false positives, yielding an average of 3.85 false positives/case.

CONCLUSIONS

The CAD software showed a sensitivity comparable to that of the general radiologists, but with more false positives. CAD detection of findings incremental to the radiologists suggests benefit when used as a second reader. Future versions of CAD have the potential to further increase clinical benefit by improving sensitivity and reducing false marks.

A randomized multi-center phase II trial of the angiogenesis inhibitor Cilengitide (EMD 121974) and gemcitabine compared with gemcitabine alone in advanced unresectable pancreatic cancer

Background

Anti-angiogenic treatment is believed to have at least cystostatic effects in highly vascularized tumours like pancreatic cancer. In this study, the treatment effects of the angiogenesis inhibitor Cilengitide and gemcitabine were compared with gemcitabine alone in patients with advanced unresectable pancreatic cancer.

Methods

A multi-national, open-label, controlled, randomized, parallel-group, phase II pilot study was conducted in 20 centers in 7 countries. Cilengitide was administered at 600 mg/m² twice weekly for 4 weeks per cycle and gemcitabine at 1000 mg/m² for 3 weeks followed by a week of rest per cycle. The planned treatment period was 6 four-week cycles. The primary endpoint of the study was overall survival and the secondary endpoints were progression-free survival (PFS), response rate, quality of life (QoL), effects on biological markers of disease (CA 19.9) and angiogenesis (vascular endothelial growth factor and basic fibroblast growth factor), and safety. An ancillary study investigated the pharmacokinetics of both drugs in a subset of patients.

Results

Eighty-nine patients were randomized. The median overall survival was 6.7 months for Cilengitide and gemcitabine and 7.7 months for gemcitabine alone. The median PFS times were 3.6 months and 3.8 months, respectively. The overall response rates were 17% and 14%, and the tumor growth control rates were 54% and 56%, respectively. Changes in the levels of CA 19.9 went in line with the clinical course of the disease, but no apparent relationships were seen with the biological markers of angiogenesis. QoL and safety evaluations were comparable between treatment groups. Pharmacokinetic studies showed no influence of gemcitabine on the pharmacokinetic parameters of Cilengitide and vice versa.

Conclusion

There were no clinically important differences observed regarding efficacy, safety and QoL between the groups. The observations lay in the range of other clinical studies in this setting. The combination regimen was well tolerated with no adverse effects on the safety, tolerability and pharmacokinetics of either agent.

Pulmonary abnormalities in immunocompromised patients: comparative detection with parallel acquisition MR imaging and thin-section helical CT

PURPOSE

To compare parallel acquisition magnetic resonance (MR) imaging with thin-section helical computed tomography (CT) for depiction of pulmonary abnormalities suggestive of pneumonia in immunocompromised patients.

MATERIALS AND METHODS

The institutional review board approved this study; prior consent was obtained. Thirty consecutive neutropenic patients (10 women, 20 men; mean age, 51 years +/- 15 [standard deviation]; range, 25-75 years) with fever of unknown origin or clinical signs and symptoms of lung infection were examined with breath-hold single-shot half-Fourier turbo spin-echo MR imaging. To reduce image blurring and increase MR signal in the lungs, the echo time was shortened with generalized autocalibrating partially parallel acquisition (GRAPPA). Patients underwent thoracic CT (four detector rows and 1-mm section thickness [4 x 1 mm]; pitch, 6) as reference standard. Pulmonary abnormalities (ill-defined nodules, ground-glass opacity areas, and consolidation), their location and distribution, and lesion characteristics were analyzed at MR imaging by three readers, blinded to results of CT, in consensus. Frequencies were calculated for each feature; paired Wilcoxon rank sum test was used to examine whether differences between CT and MR imaging features were statistically significant (alpha < .05). Bonferroni adjustments were performed. Overall sensitivity, specificity, and positive and negative predictive values were determined.

RESULTS

Twenty-two patients had pulmonary abnormalities at CT. In 21 (95%) patients, pneumonia was correctly diagnosed with MR imaging. One false-negative finding occurred in a patient with ill-defined nodules smaller than 1 cm at CT. One false-positive finding with MR imaging was the result of blurring and respiratory artifacts (sensitivity, 95%; specificity, 88%; positive predictive value, 95%; negative predictive value, 88%). There was no significant difference in lesion location and distribution.

CONCLUSION

With parallel imaging (GRAPPA technique) and fast MR imaging, detection of pulmonary abnormalities is almost as good as with CT. MR imaging has a slight disadvantage in its lower capability to assist in characterization of specific internal features, such as cavitations.

Nachweis von pneumonischen Infiltraten mit der MRT

Magnetic resonance imaging (MRI) of the lung is challenging because of substantial drawbacks. However, lung pathologies that are associated with increased attenuation values in CT enhance visualization in MRI: proton density is increased and tissue-air interfaces, resulting in susceptibility artifacts, are reduced in pneumonia, pneumonitis, edema, and carcinoma. On the other hand, many lung diseases result in shortness of breath, so that patients cannot hold their breath for long periods. Therefore, fast imaging techniques are required which should also allow for high spatial resolution so that small lesions can be detected. Calcifications and air pockets within lesions are not readily recognized with MRI. Thin section CT is standard for the diagnosis of pneumonia. With parallel imaging techniques, MRI examination of the lungs can be performed with short periods of breath holding, which allow for sub-centimeter resolution in the z-axis. Especially for follow-up examinations in immunocompromised patients and, in some instances, for the staging of malignant diseases (malignant pleural mesothelioma, lung cancer, respectively), MRI is very promising and may contribute to a decrease in the radiation exposure of the patients.

Dose reduction in multidetector CT of the urinary tract. Studies in a phantom model

A novel ureter phantom was developed for investigations of image quality and dose in CT urography. The ureter phantom consisted of a water box (14 cm x 32 cm x 42 cm) with five parallel plastic tubes (diameter 2.7 mm) filled with different concentrations of contrast media (1.88-30 mg iodine/ml). CT density of the tubes and noise of the surrounding water were determined using two multidetector scanners (Philips MX8000 with four rows, Siemens Sensation 16 with 16 rows) with varying tube current-time product (15-100 mAs per slice), voltage (90 kV, 100 kV, 120 kV), pitch (0.875-1.75), and slice thickness (1 mm, 2 mm, 3.2 mm). Contrast-to-noise ratio as a parameter of image quality was correlated with dose (CTDI) and was compared with image evaluation by two radiologists. The CT densities of different concentrations of contrast media and contrast-to-noise ratio were significantly higher when low voltages (90 kV versus 120 kV, 100 kV versus 120 kV) were applied. Smaller slice thickness (1 mm versus 2 mm) did not change CT density but decreased contrast-to-noise ratio due to increased noise. Contrast phantom studies showed favourable effects of low tube voltage on image quality in the low dose range. This may facilitate substantial dose reduction in CT urography.

High-resolution whole-body magnetic resonance image tumor staging with the use of parallel imaging versus dual-modality positron emission tomography-computed tomography: experience on a 32-channel system

OBJECTIVE

The objective of this study was to compare the accuracy in staging of various malignant tumors with whole-body magnetic resonance imaging (WB-MRI) using parallel imaging (PAT) and positron emission tomography-computed tomography (PET-CT).

MATERIALS AND METHODS

In a prospective study, 41 patients withoncologic diseases underwent [F]-fluoro-2-deoxy-D-glucose PET-CT for tumor staging and WB-MRI on a 32-channel-scanner with the use of PAT. Coronal T1w and STIR sequences at 5 body levels, axial HASTE imaging of the lung, and contrast-enhanced T1w sequences of the liver, brain, and abdomen were performed. TNM stage was assessed for both modalities in a separate consensus reading using histologic results and radiologic follow up within 6 months as the standard of reference.

RESULTS

Three primary and 4 recurrent tumors were detected; one recurrent tumor was missed with WB-MRI. Sixty benign and 60 malignant lymph nodes were detected with a sensitivity of 98% and specificity of 83% for PET-CT and 80%/75% for WB-MRI, respectively. One hundred ninety-one malignant and 77 benign distant lesions were detected with a sensitivity/specificity of 82% for PET-CT and 96%/82% for WB-MRI. Accuracy for correct TNM staging was 96% for PET-CT and 91% for WB-MRI.

CONCLUSION

WB-MRI and PET-CT are reliable imaging modalities for tumor staging. WB-MRI is highly sensitive in detecting distant metastases; PET-CT is superior in lymph node staging. PAT makes high-resolution WB-MRI feasible within less than 1 hour.

Computer-aided diagnosis as a second reader: spectrum of findings in CT studies of the chest interpreted as normal

STUDY OBJECTIVES

To assess the performance of an automated computer-aided detection (CAD) system as a second reader on chest CT studies interpreted as normal at routine clinical interpretation.

DESIGN

Chest CT studies were processed using a prototype CAD system for automated detection of lung lesions. Three experienced radiologists analyzed each CAD finding and confirmed or dismissed the marked image features as lung lesions. Noncalcified, focal lung lesions were classified according to size as being of high (> or = 10 mm), intermediate (5 to 9 mm), or low (< or = 4 mm) significance.

SETTING

Two sub-specialized academic tertiary referral centers in the United States and Germany.

PATIENTS

Chest CT studies were performed in 100 patients, with results initially reported as normal at clinical double reading. Indications for chest CT were suspected pulmonary embolism (PE) [n = 33], lung cancer screening in a high-risk population (n = 28), or follow-up for a cancer history (n = 39).

INTERVENTIONS

Reevaluation of all chest CT studies for focal lung lesions with the CAD system as a second reader.

MEASUREMENTS

Prevalence and spectrum of lung lesions missed at routine clinical interpretation but found by the CAD system.

RESULTS

In 33% (33 of 100 patients), CAD detected significant lung lesions that were not previously reported. Fifty-three significant lesions were detected (mean, 1.6 lesions per case), of which 5 lesions (9.4%) were of high significance, 21 lesions (39.6%) were of intermediate significance, and 27 lesions (50.9%) were of low significance. In the PE group, the lung cancer screening group, and the group with a cancer history, four patients (12.1%), six patients (21.4%), and nine patients (23.1%), respectively, had focal lung lesions of high and/or intermediate significance. The false-positive rate of the CAD system was an average of 1.25 per case (range, 0 to 11).

CONCLUSIONS

Significant lung lesions are frequently missed at routine clinical interpretation of chest CT studies but may be detected if CAD is used as an additional reader.

18F-FDG PET/CT for staging of penile cancer

The value of PET or PET/CT with (18)F-FDG for the staging of penile cancer has yet to be determined. The objective of this study was to investigate the pattern of (18)F-FDG uptake in the primary malignancy and its metastases and to determine the diagnostic value of (18)F-FDG PET/CT in the staging and restaging of penile cancer.

METHODS

Thirteen patients (mean +/- SD age, 64 +/- 14.0 y) with suspected penile cancer or suspected recurrent disease were examined with a Gemini PET/CT system (200 MBq of (18)F-FDG). The reference standard was based on histopathologic findings obtained at biopsy or during surgery.

RESULTS

Both the primary tumor and regional lymph node metastases exhibited a pattern of (18)F-FDG uptake typical for malignancy. Sensitivity in the detection of primary lesions was 75% (6/8), and specificity was 75% (3/4). On a per-patient basis, sensitivity in the detection of lymph node metastases was 80% (4/5), and specificity was 100% (8/8). On a nodal-group basis, PET/CT showed a sensitivity of 89% (8/9) in the detection of metastases in the superficial inguinal lymph node basins and a sensitivity of 100% (7/7) in the deep inguinal and obturator lymph node basins. The mean +/- SD maximum standardized uptake value for the 8 primary lesions was 5.3 +/- 3.7, and that for the 16 lymph node metastases was 4.6 +/- 2.0.

CONCLUSION

According to our results, the main indication for (18)F-FDG PET in the primary staging or follow-up of penile cancer patients may be the prognostically crucial search for lymph node metastases. With the use of a PET/CT unit, the additional information provided by CT may be especially useful for planning surgery. Implementing (18)F-FDG PET and PET/CT in future staging algorithms may lead to a more precise and stage-appropriate therapeutic strategy. Furthermore, invasive procedures with a high morbidity rate, such as general bilateral lymphadenectomy, may be avoided.

Approaches to CT perfusion imaging in pulmonary embolism

Computed tomography (CT) has become an increasingly accepted technique and is the method of choice for direct visualization of pulmonary emboli (PE). The quantitative assessment of tissue perfusion may yield more important information for patient management than the direct visualization of emboli by CT alone. Several attempts have been made to measure pulmonary blood flow by administration of intravenous contrast material. In this article, various experimental CT approaches for visualization and quantification of pulmonary perfusion are discussed. Ideally, CT will be able to provide both structural and functional information. Simple measurement of lung density before and after intravenous contrast delivery has been performed with single-slice CT technology using region-of-interest methodology. For electron-beam CT, a repeated data acquisition on a 7.6-cm lung volume has proven to be technically feasible. Using such dynamic scanning, reduced blood flow was observed in occluded lung segments. Color-encoded parenchymal density distribution in the axial, coronal, and sagittal planes was derived from thin collimation data sets using four-row multi-slice spiral CT (MSCT). Initial animal data from 16-slice MSCT offer a real CT-subtraction technique of the entire chest for the first time.