The diagnostic performance of 18 fluorine-fluorodeoxyglucose PET for brain metastases: a systematic review and meta-analysis.

INTRODUCTION: Brain metastases may manifest as hypermetabolism or hypometabolism compared with normal brain activity on 18 fluorine-fluorodeoxyglucose PET ( 18 F-FDG PET). We aim to undertake a systematic review and meta-analysis to determine the diagnostic accuracy of FDG PET for detecting brain metastases from different extracranial primary cancers. METHODS: PubMed and EMBASE were searched systematically. Study selection and quality assessment were performed independently by two authors. Meta-analysis was performed using a bivariate random-effects model. Subgroup analysis and meta-regression would be performed if heterogeneity was found. RESULTS: A total of 2227 patients from 11 studies were included in the review and analysis. Using the bivariate random-effects model, summary patient-based sensitivity and specificity for all 11 studies were estimated to be 0.440 [95% confidence interval (CI)] 0.295-0.597) and 0.997 (95% CI, 0.977-1.000). In view of significant between-study heterogeneity ( I2  = 74.0% for sensitivity and I2  = 67.3% for specificity), subgroup analyses were performed. Meta-regression showed significantly higher patient-based summary sensitivity for the three better-quality studies (a total of 1037 patients) with satisfactory index test (counting both hypermetabolism and hypometabolism as positive index test) and satisfactory reference standards (other imaging and clinical follow-up) compared with other included studies [0.735 (95% CI, 0.601-0.836) vs 0.304 (95% CI, 0.223-0.400), P value = 0.000]. CONCLUSION: Our systematic review and meta-analysis showed that FDG PET has overall limited sensitivity and excellent specificity in the detection of brain metastases from extracranial primary cancers. Importantly, subgroup analyses showed that the sensitivity can be significantly improved by raising awareness of asymmetrical hypometabolism. Further studies are warranted to assess the benefits of including the brain in FDG PET studies for all or certain groups of oncological patients.

A case series of FDG PET scan: hypometabolic lesions that matter in oncology.

Interpretation of FDG PET images in oncology patients is in general a visual exercise of search for focal increased uptake (hypermetabolism). However, in some cases, hypometabolism (focal decreased uptake) can matter as much as hypermetabolism. We report three cases of FDG PET studies for oncological indications. All of them showed focal hypometabolic lesions suspicious of metastases. The diagnoses were then supported either by histological proof and/or follow-up imaging studies. The importance of being alert to both focal hypermetabolism and focal hypometabolism when interpreting FDG PET images is underscored.

The diagnostic value of hepatobiliary scintigraphy for choledochal cysts in the era of magnetic resonance imaging with cholangiopancreatography and contrast-enhanced hepatobiliary phase: a case report and review.

Objective: Choledochal cysts (CCs) represent cystic dilatations of the intra- or extrahepatic biliary tract. The diagnosis of CCs may not always be straightforward particularly for the intrahepatic subtype. Whereas the gold standard for diagnosing CCs is endoscopic retrograde cholangiopancreatography (ERCP), magnetic resonance cholangiopancreatography (MRCP) is commonly used as primary diagnostic tool for delineation of biliary pathologies including CCs. Methods: We report a case of cystic hepatic lesion near the confluence of bilateral intrahepatic ducts. MRCP shows direct anatomical communication between the lesion and the biliary tract, raising suspicion of a CC. Endoscopic ultrasound shows no communication between the lesion and biliary system. 99mTc-hepatic iminodiacetic acid scintigraphy (hepatobiliary scintigraphy) was subsequently performed, showing no tracer uptake in the concerned cystic hepatic lesion despite visualisation of gallbladder and transit of tracer into the intestine. Overall scintigraphic findings speak against a CC. Conclusion: The case showed conflicting anatomical findings of a CC on MRCP and endoscopic ultrasound. Hepatobiliary scintigraphy and hepatobiliary contrast MRI may both functionally demonstrate communication of a hepatic lesion with the biliary tract. But hepatobiliary scintigraphy offers the advantage of much higher hepatic extraction and hence higher resistance to competition from plasma bilirubin compared with hepatobiliary contrast MRI. The better pharmacokinetics of HIDA confer superior lesion contrast that may offset inferior image spatial resolution, in particular for large lesions and patients with hyperbilirubinaemia. Hepatobiliary scintigraphy should be considered a suitable functional diagnostic modality for CCs even in the era of magnetic resonance imaging with cholangiopancreatography and contrast-enhanced hepatobiliary phase.

HIV status: the prima facie right not to know the result.

When a patient regains consciousness from Cryptococcus meningitis, the clinician may offer an HIV test (in case it has not already been done) (scenario 1) or offer to tell the patient his HIV status (in case the test has already been performed with a positive result while the patient was unconscious) (scenario 2). Youngs and Simmonds proposed that the patient has the prima facie right to refuse an HIV test in scenario 1 but not the prima facie right not to be told the HIV status in scenario 2. I submit that the claims to the right of refusal in both scenarios are similarly strong as they should both be grounded in privacy, self determination or dignity. But a conscientious agent should bear in mind that members of the public also have the right not to be harmed. When the circumstance allows, a proper balance of the potential benefits and harm for all the competing parties should guide the clinical decision as to whose right should finally prevail. Where a full ethical analysis is not possible, the presumption should favour respecting the patient's right of refusal in both scenarios.

A child born with Edward's syndrome: the legal and moral duty to accede to the request for parentage determination.

Advances in medical technology inevitably bring about different kinds of ethical challenges for practising doctors. The following hypothetical case of assisted reproduction is presented as an example. A boy is born with Edward's syndrome following assisted reproduction. The parents suspect that there has been an error of embryo mix-up. They challenge the parenthood and request a genetic test to determine the biological parentage of the neonate. Should the attending paediatrician in this case accede to the request? We argue that the paediatrician has no legal obligation to offer the test, although it might be lawful and ethical to provide the test subject to the outcome of our proposed three-step risk assessment.

The best interests of persistently vegetative patients: to die rather that to live?

Adults without the capacity to make their own medical decisions have their rights protected under the Mental Capacity Act (2005) in the UK. The underlying principle of the court's decisions is the best interests test, and the evaluation of best interests is a welfare appraisal. Although the House of Lords in the well-known case of Bland held that the decision to withhold treatment for patients in a persistent vegetative state should not be based on their best interests, judges in recent cases have still held that the best interests of persistently vegetative patients demand that the right to die with dignity prevails over society's interest to preserve life. The basis of suggesting that it is in the best interests for one who is alive (although vegetative) in peace to die in peace is weak. Even if it may not be in their best interests to live on, it may not be so to die either. The phrase 'the right to dignity/to die with dignity' has been misused as a trump card to justify the speculation that a vegetative patient would necessarily refuse to live on machines. Without disrespect to the court's decision, we argue that the use of the best interests test to authorise withdrawing/withholding treatment from persistently vegetative patients without an advance directive is problematic. We propose that the court could have reached the same decision by considering only the futility of treatment without working through the controversial best interests of the patient.

Should we continue treatment for M? The benefits of living.

Wilkinson and Savulescu did not agree with the court's decision to continue M's treatment and suggested in their recent commentary that the magnitude of benefits of being alive for M is small compared with the potential use of health resources for other patients. We argue that the benefits of being sensate to the surroundings for an otherwise unconscious person are not necessarily small. One cannot assess on behalf of another person the magnitude of benefits of being alive according to the intensity or the duration of negative experiences. Denying life-sustaining treatment to patients in a minimally conscious state solely on the grounds that they are less capable of enjoying the benefits represents grave discrimination against disabled persons. For patients in a minimally conscious state who have not delegated a surrogate or made any advance decision about their medical treatment, the duty of doctors is to preserve their right to self-determination and maximise their capacity to enjoy their life. M should live on, and life-sustaining treatment should not be withdrawn.

The policy statement of the American Academy of Pediatrics -- children as hematopoietic stem cell donors -- a proposal of modifications for application in the UK.

BACKGROUND: With a view to addressing the moral concerns about the use of donor siblings, the Policy Statement of the American Academy of Pediatrics - Children as Hematopoietic Stem Cell Donors (the Policy) has laid out the criteria upon which tissue harvest from a minor would be permissible. DISCUSSION: Although tissue harvest serves the best interests of recipient siblings, parents are also obliged to act in the best interests of the donor sibling in the UK. Tissue harvest should proceed if and only if it serves the best interests of both the donor and recipient. Parents should be forbidden, and they are by UK law, to consent to tissue harvest unless there are substantial benefits for an incompetent minor that can outweigh the potential harm. There is no basis to subject a minor to the medical risks of tissue harvest if the recipient sibling can wait without significant risks of complications until the donor becomes Gillick competent. We also argue that the Policy fails to take into account recent advances in haematopoietic transplantation from haploidentical donors or related tissue-matched donors. SUMMARY: Unless a recipient sibling will suffer from serious complications or die without the transplantation and no other medically equivalent donors are available, there is no moral or legal basis to violate the donor sibling's right to bodily integrity. Accordingly, we propose that the Policy should be modified in order to fully satisfy the legal requirements for application in the UK and other commonwealth jurisdictions with similar statute laws protecting minors.

A public opinion survey: is presumed consent the answer to kidney shortage in Hong Kong?

OBJECTIVE: To project the impact of an opt-out system (presuming consent) in Hong Kong on the likelihood that a potential donor donates his or her kidneys after death and the likelihood of violating a potential donor's autonomy. SETTING: Cross-sectional population-based anonymous telephone survey. PARTICIPANTS: Random sample of 802 adults aged between 18 and 64. MAIN OUTCOME MEASURE: Willingness to donate their own kidneys after death and their willingness to donate the kidneys of a deceased family member in different hypothetical situations under the current opt-in system and under our proposed soft version of an opt-out system. RESULTS: When the wish of the deceased is unknown, 72.6% (n=583) of the respondents said that under the proposed opt-out system, they would definitely or likely consent to donating the kidneys of a deceased family member, significantly more than under the current opt-in system (OR 2.53, 95% CI 2.06 to 3.11). An opt-out system could significantly improve the projected overall donation potential from 0.631 to 0.771 (OR 1.97, 95% CI 1.58-2.45) and reduce the projected overall chance of violating the autonomy of a potential donor from 0.292 to 0.127 (OR 0.35, 95% CI 0.27 to 0.45). CONCLUSIONS: A switch to an opt-out system in Hong Kong would likely result in the wishes of more people being followed and raise the overall cadaveric kidney donation rate.