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Thứ Ba, 29 tháng 7, 2014

MULTICOMPARTMENT PELVIC FLOOR ULTRASOUND



Abstract

Objective:

Comprehensive assessment of the pelvic floor (PF) provides information and diagnoses of coexisting abnormalities that may affect operative decisions. Our aim was to establish if pre-operative PF ultrasonography (PFUS) in patients complaining of PF dysfunction can complement clinical findings and contribute to additional management strategies.

Methods:

Females were recruited from the urogynaecology/gynaecology clinics between July and October 2009 and underwent pelvic organ prolapse quantification (POPQ) by an independent examiner. PFUS was performed using two-dimensional (2D) transperineal ultrasound (TPUS), high-frequency 2D/three-dimensional (3D) endovaginal ultrasound (EVUS) using a biplane probe with linear and transverse arrays and a 360° rotational 3D-EVUS. The clinician performing PFUS was blinded to POPQ results. POPQ and PFUS were repeated at 1 year. Two clinicians analysed the scans independently.

Results:

158 of 160 females had a POPQ and PFUS. 105 females had pelvic organ prolapse and/or incontinence and 53 asymptomatic females were controls. 26 additional ultrasound diagnoses were noted at baseline and 46 at 1 year using 2D-TPUS and EVUS. Only one female with additional diagnoses on PFUS needed surgical intervention for this condition.

Conclusion:

Multicompartment PFUS identifies additional conditions to that diagnosed on clinical assessment. However, it neither changes the initial surgical management nor the management at 1-year follow-up and therefore clinical assessment should not be substituted by PFUS.

Advances in knowledge:

PFUS can be helpful in providing additional information; however, it does not change the initial management of the patient and therefore should not replace clinical assessment.

Thứ Năm, 24 tháng 7, 2014

PREHOSPITAL ULTRASOUND






Introduction

Ultrasound (US) is a useful diagnostic tool for use in hospitals. It is noninvasive and inexpensive, and causes no radiation exposure. Besides radiologists, many emergency physicians use US to assist in their decision making during critical conditions [1]. With the current improvement in technology, US machines have become more portable and are available with a better resolution. Ziegler et al [2] reported that a portable device had approximately 90% accuracy compared with high-end devices. US machines such as PRIMEDIC HandyScan, V-scan, and Sonosite are commonly used as portable devices in prehospital settings.
US has been brought to prehospital settings as a result of the recent advances in technology [3]. A prehospital setting is a unique, most likely noisy, and often limited space. Traditionally, diagnostic tools used in prehospital settings are based on history taking and physical examination.
Physical examination alone cannot be sufficient to diagnose certain conditions [4]. In addition, many studies suggested that prehospital US can change the final diagnosis and treatment [5,6]. Prehospital US has a variety of applications, such as focused assessment with sonography in trauma (FAST) [5], assessment of cardiac arrest [7], lung US (mainly in pneumothorax) [6,8], and others. Countries that have studied prehospital US extensively include Germany, France, Italy, and the United states [9]. Literature was reviewed and discussed in the following sections.

Feasibility of US in a prehospital environment

Because a prehospital space is unique and limited, a US machine should be smaller in size but should have better image quality. Some studies performed US at the scene, and others in a vehicle, such as an ambulance or a helicopter. If performed at the scene, the delivery time to hospital may be prolonged, and if performed in a helicopter or an ambulance, the transporting environment may influence the scan. There are studies of prehospital US in a fixed wing and helicopter, which showed good results. However, Melanson et al [10] reported in their study that the lack of sufficient time during helicopter transport and a proper lighting system in the helicopter can compromise the results of FAST examination. Snaith et al [11] reported that FAST and abdominal aortic aneurysm (AAA) performed in a static and ground ambulance is of good quality due to the availability of sufficient time and is comparable to that performed at the emergency department.
In Taiwan, emergency medical services mainly involve ground ambulances, and most of the ambulance beds are located at the left side; hence, left-hand-based practice may be helpful for performing the scan. Fixation of machines to the frontal areas of ground ambulances may be helpful in reducing shaking.







Educating paramedics about US
Many studies have invested in the learning curve for US, especially in FAST. They concluded that a 1-day course,including lecture and hand-on practice, can generate good accuracy and competency [12]. Heegaard et al [13] designed a FAST training course, which lasted 7 hours, for emergency nurses and paramedic flight crews; they reported 100% sensitivity and specificity in nontrauma patients, and 60% sensitivity and 93% specificity in trauma patients after 1 year of training. Kim et al [14] also reported that a 4-hour FAST training course for intermediate emergency medical technicians (EMT) resulted in 61% sensitivity and 96.3% specificity.

Thứ Tư, 23 tháng 7, 2014

USEFUL

USEFUL: Ultrasound Exam for Underlying Lesions Incorporated into Physical Exam
Jon Steller, MD, Bianca Russell, MD, Shahram Lotfipour, MD, MPH, Graciela Maldonado, MD, Tim Siepel, MD, Halsey Jakle, MD, Stacy Hata, BS, Alan Chiem, MD, RDMS, John Christian Fox, MD, RDMSDisclosures
Western J Emerg Med. 2014;15(3):260-266.

ABSTRACT

Introduction: The Ultrasound Screening Exam for Underlying Lesions (USEFUL) was developed in an attempt to establish a role for bedside ultrasound in the primary and preventive care setting. It is the purpose of our pilot study to determine if students were first capable of performing all of the various scans required of our USEFUL while defining such an ultrasound-assisted physical exam that would supplement the standard hands-on physical exam in the same head-to-toe structure. We also aimed to assess the time needed for an adequate exam and analyze if times improved with repetition and previous ultrasound training.

Methods: Medical students with ranging levels of ultrasound training received a 25-minute presentation on our USEFUL followed by a 30-minute hands-on session. Following the hands-on session, the students were asked to perform a timed USEFUL on 2–3 standardized subjects. All images were documented as normal or abnormal with the understanding that an official detailed exam would be performed if an abnormality were to be found. All images were read and deemed adequate by board eligible emergency medicine ultrasound fellows.

Results: Twenty-six exams were performed by 9 students. The average time spent by all students per USEFUL was 11 minutes and 19 seconds. Students who had received the University of California, Irvine School of Medicine's integrated ultrasound curriculum performed the USEFUL significantly faster (p< 0.0025). The time it took to complete the USEFUL ranged from 6 minutes and 32 seconds to 17 minutes, and improvement was seen with each USEFUL performed. The average time to complete the USEFUL on the first standardized patient was 13 minutes and 20 seconds, while 11 minutes and 2 seconds, and 9 minutes and 20 seconds were spent performing the exam on the second and third patient, respectively.

Conclusion: Students were able to effectively complete all scans required by the USEFUL in a timely manner. Students who have been a part of the integrated ultrasound in medicine curriculum performed the USEFUL significantly faster than students who had not. Students were able to significantly improve upon the time it took them to complete the USEFUL with successive attempts. Future endpoints are aimed at assessing the feasibility and outcomes of an ultrasound-assisted physical exam in a primary care setting and the exam's effect on doctor-patient satisfaction.

Introduction

Records of Hippocratic physical examinations, influenced by the Egyptian, Cretan and Babylonian exams taught before them, included: careful history taking, inspection, palpation, and direct auscultation, and are a tradition that has continued on for thousands of years.[1] It is a great model, yet it is one that has seen few technological advances. Progress was made with the invention of the stethoscope by Laennec in 1816, and was further improved upon by Leyton, Kerr, Bowles, Rappaport, Sprague and Littmann. As newer stethoscopes improved the diagnostic sensitivity and specificity of auscultation, they were implemented into the physical examination. For Ramsay once wrote of Dr. Leyton in the British Medical Journal in 1916, "In spite of careful inquiry into the history of cases and in spite of the many accurate methods of investigation which are nowadays at our command, we cannot invariably form a perfectly definite opinion as to the cause of a patient's symptoms. Any new instrument, therefore, which can help us in our decisions should be of real use to the profession."[2] While his message encourages progress, utilization of new tools in medicine requires a detailed examination of risks and benefits. In modern medicine, we struggle to balance the cost of innovation, time constraints, management of incidental and benign exam findings, patient satisfaction, and managed health care. Our skepticism and curiosity of medical advances drive the use of the scientific method to investigate such developments before they are accepted and implemented by the community of physicians—before they can drive progress.

Over the years, various uses of bedside ultrasound have been adopted by specialties including emergency medicine, obstetrics and gynecology, and trauma. While its use in those fields has been rigorously studied in clinical settings and is the preferred first-line imaging modality for assessment of many of the organs in the abdomen and pelvis,[3] little has been reported on its role in an outpatient primary care setting and this has inspired us to consider the possible role of ultrasound as an addition to the standard physical exam. Given the recent affordability and improved image quality of bedside ultrasound units, we believe bedside ultrasound could be the new figurative stethoscope.

With this first paper, our primary endpoints were to examine the feasibility and time requirements of a medical student-performed ultrasound-assisted physical exam, termed the Ultrasound Screening Exam for Underlying Lesions (USEFUL), wherein students with varying levels of expertise would be evaluated on their ability to correctly and efficiently image individual organs from head to toe. We also sought to define our ultrasound-assisted physical exam for further medical student education and for clinicians interested in integrating ultrasound into their physical exams. Aware of the time restraints for physicians in outpatient clinics, we determined six minutes or less would be an acceptable length for a USEFUL and hoped this would be a reasonable goal. The USEFUL was developed by students and faculty interested in establishing a role for bedside ultrasound in the primary and preventive care setting with the hope that, in the future, an ultrasound-assisted physical exam that would take approximately six minutes might supplement the standard hands-on physical exam.

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Thứ Ba, 15 tháng 7, 2014

US ELASTOGRAPHY for VARICOSE VEINS of LOWER EXTREMITIES

Aims and objectives
To assess a feasibility of ultrasound elastography for monitoring of conservative therapy of the varicose veins of lower extremities with a drug containing micronized purified flavonoid fraction (MPFF).

Ultrasound elastography, as a technique evaluating the elastic properties (stiffness) of tissues, was carried out after standard ultrasound examination. The elasticity of biological tissue describes its ability of reversible deformation, i.e. the property to exert mechanical resistance when the force is applied and to regain the original shape after removal of force. Elastography image is a graphical representation of the displacement of tissue layers under the influence of several cycles of compression/decompression of the investigated vein by sensor. The received echo signal is processed by the device, and the color-coded information on the displaceability of the studied tissue layers is displayed.


The dense tissue is indicated in blue, the tissue with moderate elasticity - in green and yellow-green, and softer tissue - in red.
According to our data, the unaltered vein has a soft-elastic structure of the vessel wall/perivasal tissues complex, which is uniformly encoded in green or yellow-green. The width of soft-elastic limbus around the vein is determined by the size of the vessel, as well as the presence of abnormalities. During the USEG of veins and adjacent tissues we evaluated the area of perivasal tissues on the posterior wall of the vessel at the moment of maximal decompression, which has a homogeneous elasticity, as well as the width of perivasal zone of tissue elasticity (Figures 1a, 1b). The vein is coded in red as the softest structure because of the presence of liquid component and formed elements that can move and, therefore, determine a high degree of relative elasticity of the tissue.




Conclusion
The study has shown that the changes identified using the ultrasound elastography are more pronounced in the vessels of large diameter. Intact veins of lower extremities have a homogeneous image of elastogram, suggesting about unaltered histological structure of these tissues. In the presence of varicose transformation, the heterogeneous elastography pattern reflected, probably, the disturbance of histological regularity of tissues surrounding the vessel.
The therapy with MPFF was associated with a trend to normalization of elastographic image of vessel, which relates to the reduction of the severity of aseptic inflammation and normalization of cellular structure, and, therefore, the physical properties of the studied tissue.

The obtained data confirm the feasibility of ultrasound elastography for identification of the objective markers of treatment response to MPFF in varicose disease.

Thứ Sáu, 11 tháng 7, 2014

Breast Ultrasound Screening, Dr. Jason Birnholz.

...

Screening mammography
Screening mammography seems to have followed a different trajectory, being a collection of separate local efforts continually fueled by an overwhelming barrage of popular media promotions. Like tainting a jury, this kind of public relations, though always well-intentioned, probably prevented an unbiased evaluation of the method itself.
In regard to studies supporting x-ray mammography, questions have been raised about the inherent validity of our most common tests for significance (i.e., Fisherian statistics) with many types of hypothesis-driven study designs. Dr. John Ioannidis made the case in a fascinating essay in 2005 that most published research findings are false.
The negative side has been met with several technical advances in x-ray mammography itself and a much deeper understanding of the molecular biology of breast cancer and the subdivision of "cancer" into subtypes with differing behaviors and drug sensitivities.
Dr. Nikola Biller-Andorno, PhD, and Dr. Peter Jüni shared their opinion that screening mammography should be discontinued in Switzerland in a recent issue of the New England Journal of Medicine (May 22, 2014, Vol. 370:21, pp. 1965-1967).
Noting that the first screening mammography trial was performed 50 years ago, Biller-Andorno and Jüni shared graphical representations of the real effect of mammography and how women perceive the effects, again emphasizing the potential bias of undocumented public thought in our interpretations of utilization studies or how we act on them.
Ultrasound and the breast
You must be wondering what, if anything, this has to do with ultrasound. It does relate -- perhaps more than you might think. One of the earliest papers on ultrasound was published by John Wild and John Reid in 1952 ("Further pilot echographic studies on the histologic structure of tumors of the living intact human breast"). This study used A-mode scanning to differentiate benign and malignant masses.
The notion of ultrasound screening was promoted in the 1980s by Dr. Elizabeth Kelly-Fry in Indianapolis and by my dear friend, the late Dr. Toshiji Kobayashi in Japan. For years I avoided this application, as I didn't think the equipment was ready.
One of the main problems ultrasound has always faced is that even a few clinical failures from technically premature use overshadow a lot of reliable uses in other applications. The other factor is that if you accept that diagnosis must be as early as possible, then you cannot beat x-ray detection of microcalcifications, which will precede the formation of a mass of abnormal cells.
I changed my mind, however, due to high-frequency, noise-suppressing equipment improvements in the past few years. Also, I had been finding a lot of advanced breast cancers with that equipment in referrals from alternate healthcare sources of patients who were fearful of MDs and who had not had any kind of surveillance other than some breast thermography, which I had thought had failed and disappeared in the 1970s.
Doing breast ultrasound is actually pretty easy. Cancers all arise in gland tissue that are the radially arranged reflective patches surrounding ducts. At higher frequencies and with noise suppression, cancers -- being more uniform in architecture -- are hypoechoic, improving inherent contrast against the parenchymal surround.
Automated breast ultrasound
Automated breast ultrasound systems (ABUS) are being promoted for screening. Seems reasonable, doesn't it? Actually, this may be the best ultrasound example I know of market-driven technology development in the absence of understanding of the clinical application.
Here's why: Detection of low-contrast targets is improved when they are moving. That has been known and studied forever. It's why that lonely sailor in the crow's nest scans the horizon instead of staring fixedly at it. Or, think of detecting a moving plane so far off that none of its features are evident. There is a sizeable collection of literature on contrast detection in static and moving images.
The automated systems have beautiful static displays, which seem to resemble the kind of images that mammographers, working with a static form of imaging, use daily. If you want to do breast nodule detection, forget automation, though, and have a human observer slide a transducer along radials from the nipple while watching the screen.
Most people who do breast ultrasound will tell you that is how you find lesions. When something has caught your eye, you go back and get static images of the nodule to document its location and features.

You could use your ABUS if you could page back and forth through the axis of the scan image set when you're reviewing the case, but that does not seem to be an efficient way for a clinic to utilize its personnel.
...

WHERE DID FREE GAS in PERITONEUM COME from ?

Poster: Free intra-abdominal gas - where did it come from? 

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Intraperitoneal gas
Perforated gastric or duodenal ulcer
Perforation of a peptic ulcer is the most common cause of pneumoperitoneum.
Anterior wall ulcers of the stomach and duodenal bulb usually perforate freely into the intraperitoneal space, initially supramesocolic, whereas posterior wall gastric ulcers perforate into the lesser sac.
Some ulcers will seal off immediately, the only radiological sign of perforation may be a small locule of gas adjacent to the stomach or in the gastroduodenal ligament.

NHÂN CA THỦNG LOÉT HÀNH TÁ TRÀNG TẠI MEDIC

Sonographic findings suggestive of peptic ulcer perforation include the presence of ascites, intraperitoneal free air and a linear echogenic band transversing the entire bowel wall.





Thứ Ba, 1 tháng 7, 2014

US Elastography for Diffuse Liver Disease: Weaknesses and Strengths


US Elastography: Weaknesses and Strengths


The most significant challenge facing US elastography is the issue of measurement reproducibility. A number of studies concerning this issue have been published; however, many investigators have brought up questions about this issue due to the inherent limitations of US such as the operator-dependent performance. 
Transient elastography is a highly reproducible and user-friendly technique [45], and liver stiffnessmeasurementby transient 
elastography does not require a learning curve: even a novice can obtain a reliable result after a single training session [46]. However, because liver stiffness measurements can be influenced significantly by steatosis, obesity, lower degrees of hepatic fibrosis [45], necroinflammation of hepatocytes [47], cholestasis [48], elevated central venous pressure [49], and even postprandial conditions [50], it should be carefully applied when used as an alternative measurement of liver
stiffness instead of liver biopsy.

In the case of ARFI, the overall reproducibility is also not bad, having an intraclass correlation coefficient (ICC) value for the interrater observation of 0.81 and an ICC for the intrarater observation of 0.90. However, gender (women), high body mass index, ascites, and lower degree of liver disease (noncirrhotic patients) are considered factors that impede the reproducibility of ARFI [51].
In the case of SSI, the inter- and intraobserver agreements have ICC values of 0.88 and 0.94, respectively, which are similar to the results of ARFI imaging [52].




Despite the issues described above, US elastography has  many advantages in clinical fields. The most important aspect is convenience, as is the case with most ultrasonography examination techniques. Indeed, US elastography is fast, easy to use, and portable, so much so that it can be performed at the patient’s bedside. Likewise, because it does not use ionizing radiation, US elastography is relatively safe, even in patients who repeatedly undergo the procedure. US elastography is also less expensive than MR elastography [53]. Going forward, the most important strength of US elastography is the availability of a large amount of accumulated clinical data that have demonstrated its clinical usefulness, although most of these data are related to transient  elastography.




Conclusions

Measurement of liver stiffness using various technical developments is evolving to overcome its limitations. Recently, the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) published an informative guideline for the use of US elastography [54,55] that deals with the relevant technology and clinical applications. Along with the basic principles for use, these guidelines include the practical advantages and disadvantages of US elastography as well as recommendations for the examination of various body parts. According to these guidelines, US elastography is useful to assess the severity of liver fibrosis in patients with diffuse liver disease and particularly to distinguish patients with nil to mild fibrosis from those with significant fibrosis, although some of the newer techniques must be validated through clinical studies. At present, however, US elastography for the differentiation of focal hepatic lesions is not recommended.


In conclusion, US elastography is useful for diagnosing hepatic fibrosis in patients with CLD and may be used as a convenient and non-invasive surveillance method to estimate the prognosis of patients with fatal complications related to CLD. Accordingly, the development of a standardized method for liver stiffness measurement and technical improvements should be a priority for the clinical application of US elastography. Together, these efforts will significantly enhance the clinical implications of US elastography.

USPSTF Finalizes AAA Screening Recommendations

By Erik L. Ridley, AuntMinnie staff writer




June 24, 2014 -- Adhering mostly to its draft statement published in January, the U.S. Preventive Services Task Force (USPSTF) included no big surprises in its new recommendations in favor of ultrasound screening for abdominal aortic aneurysms (AAAs).

In a notable change from its previous 2005 statement, the task force added nuance to its recommendations for ultrasound screening for AAA in women, providing separate guidance for women who have smoked and those who haven't. In 2005, USPSTF recommended against screening in all women; however, the task force has now concluded that current evidence is insufficient to assess the balance of benefits and harms of ultrasound screening in women 65 to 75 who have ever smoked. It continues to recommend against screening in women who have never smoked.

The final recommendations, which were published online June 23 in the Annals of Internal Medicine, also retained the task force's 2005 B-grade recommendation for one-time ultrasound screening for AAA in men 65 to 75 who have ever smoked. In keeping with a change to the definition of its C grade level, USPSTF now suggests selective screening for men of this age group who have never smoked. In 2005, the same C grade level indicated that the task force made no recommendation for or against screening.



AAA screening in women

The task force noted that only one randomized, controlled trial on AAA screening included women, and the trial found no difference in AAA rupture, AAA-specific mortality, or all-cause mortality between screened women and a control group. The group also pointed out that women age 70 years who have ever smoked have an overall AAA rupture prevalence of approximately 0.8%, while current smokers have a prevalence of approximately 2%.

"However, the single [randomized, controlled trial] of screening for AAA that included women was underpowered to draw definitive conclusions by sex, and the prevalence of AAA in women who currently smoke approaches that of men who have never smoked," they wrote. "As such, a small net benefit might exist for this population and appropriate, high-quality research designs should be used to address this question."

As a result, the task force determined that the evidence was inadequate to conclude whether one-time ultrasound screening for AAA was beneficial in women ages 65 to 75 years who have ever smoked.

The task force also said that the prevalence of AAA in women who have never smoked ranges from only 0.03% to 0.6% for ages 50 to 79, and there is no evidence of apparent benefit of screening for AAA in this group of women.

"The USPSTF therefore concludes that adequate evidence shows that the absolute benefit of one-time screening for AAA with ultrasonography in women who have never smoked can effectively be bounded at none or almost none," the group wrote.

The task force also observed that women had a slightly higher risk of AAA surgery-related death than men. Women had 7% operative mortality with open repair, compared with 5% for men, and 2% for endovascular repair, compared with 1% for men.

"Convincing evidence shows that the harms associated with one-time screening for AAA with ultrasonography are at least small in all populations and potentially higher in women because of their higher risk for operative mortality," they wrote.

AAA screening in men

The task force reiterated that there is convincing evidence that one-time ultrasound screening for AAA yields a moderate benefit in men ages 65 to 75 years who have ever smoked. However, the lower prevalence of AAA in men who have never smoked substantially reduces the absolute benefit of screening in this group of men.

"Despite the demonstrated benefits of screening for AAA in men overall, the lower prevalence of AAA in male never-smokers versus male ever-smokers suggests that clinicians should consider a patient's risk factors and the potential for harm before screening for AAA rather than routinely offering screening to all male never-smokers," the task force wrote.

The group noted that important risk factors for AAA include older age and a first-degree relative with an AAA; other risk factors include a history of other vascular aneurysms, coronary artery disease, cerebrovascular disease, atherosclerosis, hypercholesterolemia, obesity, and hypertension. Also, factors associated with a reduced risk for AAA include African-American race, Hispanic ethnicity, and diabetes.

Draft changes

Changes made to the draft version included clarification of the definition of an "ever-smoker" and information about the absolute benefits of screening for AAA to provide additional context for the reported reductions in relative risk, according to the task force. USPSTF also expanded the discussion relating to the risks and benefits of screening and treatment in women compared with those in men.

"Finally, the USPSTF emphasized that more research -- including high-quality modeling studies -- is required to better understand the relative benefits and harms of screening for AAA in men and women with a family history of AAA and for women who have ever smoked," they wrote.

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Analysis Finds Evidence Lacking for HCC Screening



June 18, 2014 -- Screening for hepatocellular carcinoma (HCC) in patients with chronic liver disease can detect early-stage cancer, but it's unclear whether systematic screening would yield a survival advantage over clinical diagnosis, according to an analysis published on Tuesday in the Annals of Internal Medicine.

The review included 22 studies in the literature and assessed the utility of methods such as ultrasound and serial alpha-fetoprotein screening. The team of researchers, led by Dr. Devan Kansagara of Portland Veterans Affairs Medical Center, found that "the body of evidence on which current recommendations for screening are based has substantial shortcomings."

The research project was commissioned by the U.S. Veterans Health Administration.

Controversial recommendations

A number of professional societies recommend using imaging methods and tumor markers for HCC screening, primarily in patients at higher risk due to chronic hepatitis B or cirrhosis; however, these recommendations remain controversial due to concerns over the quality and paucity of existing evidence to support screening, and the potential of overdiagnosis and patient harms, according to the researchers.

To better understand the incremental benefits and harms of routine HCC screening compared with clinical diagnosis, the study team conducted a systematic review of the literature. They searched Medline, PsycInfo, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov from the inception of the databases to June 2013. They later updated the Medline, PsycInfo, and ClinicalTrials.gov searches in April 2014 (Ann Intern Med, June 17, 2014).

Kansagara and colleagues included all English-language controlled clinical trials and observational studies that assessed the effects of screening on HCC-specific and all-cause mortality in adults. Studies also had to include a comparison group of patients who did not have routine screening. Observational studies that did not consider important confounding factors were excluded. Using a tool developed by the Cochrane Collaboration, two reviewers independently assessed each included trial's quality, and disagreements were resolved through discussion.

Two reviewers also graded the strength of evidence for outcomes by using published criteria that considered a body of evidence as well as the internal validity of individual studies, according to the researchers. In addition, existing tools were adapted to evaluate the quality of observational studies.

Low-strength evidence

Of the 286 potentially relevant studies gathered from the literature search, 22 studies met the group's inclusion criteria. Of these 22, two trials and 18 observational studies provided only very-low-strength evidence regarding the effect of HCC screening on mortality.

The researchers concluded that the two trials -- both conducted in China -- had substantial methodological flaws that threatened their internal validity, and their findings have limited applicability beyond the hepatitis B patient population. They also noted, though, that the observational studies, most of which included patients with cirrhosis and hepatitis B, hepatitis C, or alcoholic liver disease, showed that screening detects patients with earlier-stage disease and who more frequently receive curative therapy.

"However, it is impossible to say whether the longer survival in patients with screen-detected disease was a true effect of screening or reflects lead- and length-time biases inherent to all observational studies, as well as selection biases that were common in many of the studies," they wrote.

Two additional trials compared ultrasound screening intervals: One was a Taiwanese study that compared four-month and 12-month screening intervals in patients with serologic evidence of hepatitis B or C. Despite more patients in the four-month screening interval group having early-stage disease, survival rates were similar among both screening intervals. Furthermore, the "study had an unclear risk of bias because of poor reporting of outcome assessment and statistical analyses," they wrote.

The other trial, which had a low risk of bias, compared three-month and six-month ultrasound screening intervals, and found similar all-cause mortality rates among both groups.

Observational studies

The 18 observational studies compared survival in patients with screening-detected HCC and those diagnosed with HCC incidentally as part of another workup or because of symptoms. The researchers noted that patients in these studies who had undergone screening had earlier-stage HCC than those who hadn't received screening. They also determined that more screened patients received potentially curative treatment, and survival was generally higher among screened patients.

However, several methodological considerations temper confidence for drawing conclusions from these studies, according to the researchers.

"Most of the studies were single-center retrospective cohort studies in which all patients with diagnosed HCC were first identified and screening status was subsequently determined," they wrote. "Few studies reported data on loss to follow-up, and many did not report using a comprehensive method to assess mortality outcomes equally in screening and nonscreening groups."

In addition, selection bias was a concern for 15 of the studies, and none of the studies reported any direct harms of screening or examined the psychological effects of screening, the authors noted.

Kansagara and colleagues concluded that there is very-low-strength evidence from which to draw conclusions about the effects of HCC screening on mortality in high-risk patients with chronic liver disease.

"Screening can identify more patients with earlier-stage disease who are candidates for potentially curative treatments, but there is limited evidence from which to draw firm conclusions about the balance of health outcome benefits and harms of using routine screening to identify HCC," the researchers wrote.

They noted, though, that their findings neither support nor refute current policy recommendations for HCC screening.

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