The routine clinical use of fluorodeoxyglucose PET/CT to confirm treatment response in pyogenic spine infection

OBJECTIVE

Response of pyogenic spine infection to antibiotic therapy is usually based on nonspecific symptoms and inflammation markers. Abnormalities on MRI persist too long to influence therapy. Is FDG-PET/CT a timely and robust predictor of successful therapy?

MATERIALS AND METHODS

Retrospective study. Sequential FDG-PET/CTs done to assess treatment response over a 4-year period. Recurrence of infection after stopping treatment was the endpoint.

RESULTS

One hundred seven patients enrolled. First treatment response scan showed no signs of infection in 69 patients (low risk). Twenty-four additional patients underwent additional treatment after an initial positive scan with low-risk pattern on follow-up imaging. After stopping antibiotics, none had clinical recurrence of infection. One had positive cultures at surgery for negative predictive value of 0.99. Thirty-eight patients had evidence of residual infection. Abnormalities in 28 were comparable to what is seen with untreated infection (high-risk). Twenty-seven received additional treatment until resolution. Antibiotics were stopped in 1 who suffered recurrence. Ten had low-grade/localized abnormalities consistent with infection (intermediate-risk). Signs of infection resolved in 3 after additional treatment. Of the remaining 7 patients who had minor residual abnormalities when antibiotics were stopped, 1 had recurrent infection for a positive predictive value of 0.14.

CONCLUSION

Risk stratification proposed: A low-risk scan with only inflammation at a destroyed joint indicates negligible risk of recurrence. Unexplained activity in bone, soft tissue or spinal canal indicates high risk with further antibiotics recommended. Most patients with subtle or localized findings (intermediate risk) did not experience recurrence. Stopping therapy could be considered under careful observation.

An international survey on the clinical use of rigid and deformable image registration in radiotherapy

OBJECTIVES

Rigid image registration (RIR) and deformable image registration (DIR) are widely used in radiotherapy. This project aims to capture current international approaches to image registration.

METHODS

A survey was designed to identify variations in use, resources, implementation, and decision-making criteria for clinical image registration. This was distributed to radiotherapy centers internationally in 2018.

RESULTS

There were 57 responses internationally, from the Americas (46%), Australia/New Zealand (32%), Europe (12%), and Asia (10%). Rigid image registration and DIR were used clinically for computed tomography (CT)-CT registration (96% and 51%, respectively), followed by CT-PET (81% and 47%), CT-CBCT (84% and 19%), CT-MR (93% and 19%), MR-MR (49% and 5%), and CT-US (9% and 0%). Respondent centers performed DIR using dedicated software (75%) and treatment planning systems (29%), with 84% having some form of DIR software. Centers have clinically implemented DIR for atlas-based segmentation (47%), multi-modality treatment planning (65%), and dose deformation (63%). The clinical use of DIR for multi-modality treatment planning and accounting for retreatments was considered to have the highest benefit-to-risk ratio (69% and 67%, respectively).

CONCLUSIONS

This survey data provides useful insights on where, when, and how image registration has been implemented in radiotherapy centers around the world. DIR is mainly in clinical use for CT-CT (51%) and CT-PET (47%) for the head and neck (43-57% over all use cases) region. The highest benefit-risk ratio for clinical use of DIR was for multi-modality treatment planning and accounting for retreatments, which also had higher clinical use than for adaptive radiotherapy and atlas-based segmentation.

COMP Report: A survey of radiation safety regulations for medical imaging x-ray equipment in Canada

X‐ray regulations and room design methodology vary widely across Canada. The Canadian Organization of Medical Physicists (COMP) conducted a survey in 2016/2017 to provide a useful snapshot of existing variations in rules and methodologies for human patient medical imaging facilities. Some jurisdictions no longer have radiation safety regulatory requirements and COMP is concerned that lack of regulatory oversight might erode safe practices. Harmonized standards will facilitate oversight that will ensure continued attention is given to public safety and to control workplace exposure. COMP encourages all Canadian jurisdictions to adopt the dose limits and constraints outlined in Health Canada Safety Code 35 with the codicil that the design standards be updated to those outlined in NCRP 147 and BIR 2012.

Perfusion CT estimates photosensitizer uptake and biodistribution in a rabbit orthotopic pancreatic cancer model: a pilot study

RATIONALE AND OBJECTIVES

It was hypothesized that perfusion computed tomography (CT), blood flow (BF), blood volume (BV), and vascular permeability surface area (PS) product parameters would be predictive of therapeutic anticancer agent uptake in pancreatic cancer, facilitating image-guided interpretation of human treatments. The hypothesis was tested in an orthotopic rabbit model of pancreatic cancer, by establishing the model, imaging with endoscopic ultrasound (EUS) and contrast CT, and spatially comparing the perfusion maps to the ex vivo uptake values of the injected photosensitizer, verteporfin.

MATERIALS AND METHODS

Nine New Zealand white rabbits underwent direct pancreas implantation of VX2 tumors, and CT perfusion or EUS was performed 10 days postimplantation. Verteporfin was injected during CT imaging, and the tissue was removed 1 hour postinjection for frozen tissue fluorescence scanning. Region-of-interest comparisons of CT data with ex vivo fluorescence and histopathologic staining were performed.

RESULTS

Dynamic contrast-enhanced CT showed enhanced BF, BV, and PS in the tumor rim and decreased BF, BV, and PS in the tumor core. Significant correlations were found between ex vivo verteporfin concentration and each of BF, BV, and PS.

CONCLUSIONS

The efficacy of verteporfin delivery in tumors is estimated by perfusion CT, providing a noninvasive method of mapping photosensitizer dose.

Effect of an angiogenesis inhibitor on hepatic tumor perfusion and the implications for adjuvant cytotoxic therapy

PURPOSE

To determine whether dynamic contrast material-enhanced (DCE) computed tomography (CT) can help identify hepatic tumor perfusion response to vascular remodeling induced by antiangiogenesis treatment in a rabbit model.

MATERIALS AND METHODS

The study was approved by the Animal Use Subcommittee of the University Council on Animal Care. DCE CT hepatic perfusion measurements were performed in the livers of 20 rabbits implanted with VX2 carcinoma. Vascular remodeling was induced with thalidomide dissolved in dimethyl sulfoxide and sterile water, starting at a tumor diameter of 0.7 cm±0.1 and continuing until metastatic lung nodules were observed. The control group (n=8) was given an equivalent volume of the vehicle. The therapy group was subdivided into animals that survived for more than 24 days without lung metastasis (responder group, n=5) or those that survived for less than 24 days (nonresponder group, n=7). Data were analyzed with the Kruskal-Wallis or Friedman rank test and reported as medians and interquartile ranges.

RESULTS

DCE CT depicted differential perfusion change within the therapy group after treatment. By day 4, hepatic blood volume (HBV) in the responder group decreased by 29.2% (-32.5% to -11.8%) relative to that before treatment and was significantly different from that in the nonresponder (P=.048) and control (P=.011) groups, where HBV remained stable. By day 8, hepatic artery blood flow decreased by 50.0% (-59.08% to -21.05%) relative to that before treatment in the responder group and was significantly different from that in the nonresponder and control groups (P=.030 for both), which remained stable at -3.5% (-8.5% to 28.7%, P=.50) and -10.0% (-33.8% to 10.4%, P=.48), respectively.

CONCLUSION

DCE CT can help differentiate responders from nonresponders by their early differential perfusion response to antiangiogenesis therapy.

Comparison of a phone vs clinic approach to achieve 10% weight loss

OBJECTIVE

To compare the efficacy of a phone vs a traditional face-to-face clinic approach to achieve 10% weight loss and weight maintenance.

DESIGN

Twenty-six week, randomized, controlled trial.

SUBJECTS

Twenty-four men and 72 women, ages 25-68 years, with a body mass index (BMI) of 33.2+/-3.8.

MEASUREMENTS

Weight loss at 12 weeks and weight maintenance at 26 weeks were the primary outcomes. Attendance, meal replacements (MRs), fruits/vegetables (F/V), and physical activity (PA) were measured weekly for process evaluation.

RESULTS

Median weight loss (range) from baseline at 12 weeks was significantly different for phone at 10.6 kg (16.6) or 10.4% and clinic at 12.7 kg (19.9) or 13.7%, and both were significantly different when compared with the control group with a weight loss of 0.25 kg (5.6) or 0.24%. Median weight loss at 26 weeks was 12.8 kg (23.4) or 13.0% from baseline for the phone group and 12.5 kg (35.2) or 12.6% from baseline for the clinic group (P>0.05).

CONCLUSION

The median weight loss for both phone and clinic groups at 12 and 26 weeks exceeded the NHLBI guideline of 10% weight loss from baseline. The phone approach may be a viable option to the traditional weight management clinic for both service providers and participants.

Correlation between hepatic tumor blood flow and glucose utilization in a rabbit liver tumor model

PURPOSE

To prospectively determine the relationship between hepatic tumor blood flow and glucose utilization in vivo by using a combined positron emission tomographic (PET)/computed tomographic (CT) scanner.

MATERIALS AND METHODS

The animal care and use subcommittee at the University of Western Ontario approved this study. VX2 carcinoma cells were implanted in the livers of eight male New Zealand white rabbits. Functional CT was performed before tumor implantation and every 4 days thereafter. Each examination consisted of two phases: In the first phase, 30-second cine breath-hold scanning was performed with simultaneous injection of 5 mL of contrast material. In the second phase, 4-second cine scanning was performed without breath holding every 10 seconds for 2 minutes. Second-phase CT images were coregistered with first-phase images to eliminate breathing artifacts. The weighted summation of the aortic and portal venous time-attenuation curves was deconvolved against curves from the liver to derive hepatic blood flow (HBF). Five animals underwent fluorine 18 fluorodeoxyglucose (FDG) scanning before and every 8 days after implantation. FDG uptake was measured as standardized uptake value (SUV). Data were analyzed with repeated-measures analysis of variance and the Tukey-Kramer multiple comparison test. Linear regression was used to compare SUV and HBF in tumors and normal tissue.

RESULTS

In the hypovascular tumor core, (a) mean HBF decreased from 262 mL.min-1.100 g-1+/-22 (standard deviation) at baseline to 101 mL.min-1.100 g-1+/-62 at the end of the study (P<.05) and (b) mean SUV increased from 2.12 g/mL+/-0.06 to 4.56 g/mL+/-0.73 (P<.05) during the same period.

CONCLUSION

Functional CT in combination with FDG PET can be used to observe changes in HBF and glucose utilization in a growing liver tumor.

OIG offers guidance on the legality of telemedicine arrangements

Telemedicine increasingly is being used to enable patients in rural areas to gain access to specialists. At the same time, concerns have arisen about the legality of certain telemedicine applications. To date, the HHS Office of Inspector General (OIG) has issued two advisory opinions stating it would not impose sanctions on two specific telemedicine arrangements, where potential violations of the antikickback statute could exist. These opinions, while applying only to the specific arrangements in question, provide physicians with clues to the OIG's thinking on various arrangements they may wish to initiate.

Ascorbate inhibits edema in brain slices

Ascorbate is an essential antioxidant in the CNS, localized predominantly in neuronal cytosol. Slices of mammalian brain rapidly lose ascorbate, however, when incubated in ascorbate-free media; brain slices also take up water and swell. Here we investigated water gain in coronal slices of rat forebrain incubated with and without ascorbate for 1-3 h at 34 degrees C. Slices progressively gained water in ascorbate-free media, with a significant 12% water increase after 3 h at 34 degrees C, compared with the water content of slices after a 1-h recovery period at 24 degrees C, immediately following slice preparation. Inclusion of 400 micro M ascorbate in the medium led to an increase in tissue ascorbate content and prevented water gain at 34 degrees C. By contrast, water gain was not inhibited by isoascorbate or thiourea, which are antioxidants that are not accumulated in brain cells. The oxidant H2O2 enhanced water gain, whereas a cocktail of NMDA and non-NMDA receptor blockers inhibited edema formation to the same extent as ascorbate. These data demonstrate that brain edema, linked to glutamate-receptor activation, can result from intracellular oxidative stress and that this can be prevented by ascorbate.

A record-retention program can protect group practices

Group practices can benefit from having a systematic record-retention program that includes a formal record-retention policy. While state and Federal laws require the retention of some types of business records, many other records should be retained in the event of an audit or litigation. Having a record-retention program in place can help group practices respond cost-effectively and efficiently when called upon to produce documentation. The record-retention program should include a policy that stipulates not only which records should be kept but also for how long. Group practices should retain records relating to patient care, taxes, payroll, and contracts.

Group practices need to ensure year 2000 compliance of their electronic systems

In a group practice, the year 2000 date problem can affect accounting, payment, and billing systems, as well as medical equipment. With the turn of the century drawing closer, group practices should ensure that all the electronic systems that affect their businesses will be year 2000 compliant. Group practices should develop a plan to address all of the possible year 2000 issues that can affect their electronic systems. A three-step procedure that will help group practices implement such a plan comprises creating an inventory of all systems that could be affected, investigating each system's compliance, and getting written assurance of year 2000 compliance from all relevant third parties.

Negotiating a sound physician office lease

Physician group practices that lease office space should consider several issues before signing a lease. These issues include whether to hire a broker to assist in the search for office space, negotiating lease provisions that pertain to compliance with the Americans with Disabilities Act; confidentiality of patient records; proper disposal of medical waste and other hazardous materials; compliance with occupational safety standards; quiet enjoyment; and utility use. In addition, physician group practices that lease office space from other healthcare providers must ensure that the lease terms conform with antifraud and abuse safe harbor regulations.

Detecting and detering employee theft

Physician group practices can limit their vulnerability to employee theft by taking steps to detect theft when it occurs and to deter future occurrences. Steps for detecting theft include being wary of an employee's refusal to take earned time off, conducting periodic credit checks on employees, rotating employees' duties, and conducting impromptu reviews of the practice's finances. Steps for detering theft include routing the practice's checks to a lock box; reviewing cash reports; reconciling check with deposit statements; separating employees' duties; reviewing bank, credit card, and ATM statements; setting the tone for prudent financial management; and reporting cases of theft when they occur.

Drafting a sound physician employment agreement

Group practices that employ physicians on a contractual basis face a number of risks. Among these risks are the possibility of employee-physicians engaging in competitive activities; the practice's potential liability for outside services its physicians may perform; and the possibility of breaches of patient and practice confidentiality. By drafting employment agreements that include provisions that minimize such risks, practices can strengthen their market position and protect themselves from potential losses.

Medicare risk contracting places new demands on physician group practices

Physician group practices new to Medicare risk contracting face unfamiliar financial and practice imperatives. Financial imperatives include accepting capitation and the risks associated with it. Practice imperatives include adhering to critical paths and admission and discharge criteria. By familiarizing themselves with the risks and rewards of Medicare risk contracting, physician group practices can make more informed decisions about entering into such arrangements.

Managed care contracting issues in integrated delivery systems

This article is a checklist for use by health care providers in reviewing proposed managed care contracting agreements. This checklist is not an exhaustive list, but is intended to be used as a framework for review.