“Do you have the old X-ray films with you?”  A question that I always ask when patients come to consult me with recent X-ray films. Why, you may ask.

A recent Dutch study examined how the performance of radiologists can be influenced when they are allowed access to previous mammograms during their reporting of current mammograms (Radiology 2007; 242: 70-77). Twelve experienced radiologists read 80 mammograms performed on women who had breast cancer diagnosed later and another 80 mammograms from women with normal breasts or breasts with benign breast disease. These radiologists read the 160 mammograms twice – once with and once without prior mammograms. Without prior mammograms for comparison, the radiologists made significantly more annotations about the current mammograms. Reading performance was significantly better when prior screening mammograms were available. At fixed lesion localized fraction, on average non-lesion localized fraction was reduced by 44% when prior mammograms were read together with current mammograms. In simple terms, the number of false alarms was reduced by 44% when prior mammograms were made available. (In all the positive cancer cases, the radiologists did not miss any of the cases with or without prior mammograms.)

X-ray films (be it CT, MRI, PET-CT, ultrasound or plain X-ray) tell a story. Old films give the doctor a record of what was there before. You can compare the old films (prior) with the new films (current). When you compare the current X-ray to the previous films, the report of a ‘lesion’ in the current X-ray may not be of significance if it was already visible in the prior X-ray. Conversely, if a shadow in the current X-ray, when compared to the prior X-ray, showed that the shadow has increased in size or has changed in shape, then it would alert the doctor to investigate the matter further.

Up until recently, X-ray pictures were produced as hard-copies and handed to you in an envelope. Now, it is becoming more common for the pictures to be handed to you in a 2.5 inch CD. While it is more convenient for you to carry the pictures around and for the X-ray establishment to keep a copy of the scan, it makes it more difficult for the clinic doctor to compare prior pictures with current ones. Why? When you have hard copy X-ray pictures, you just place the old film next to the new one on the X-ray box to perform a direct comparison. When you call up the old and the new soft copy images, you can’t place them side by side. You have to click on each icon to ‘bring’ it up on your computer screen. It makes comparison more difficult. (For the radiologist this is not an issue because they have the soft ware installed on the machine to do just that.) When the radiologists read the soft copy, they have a big screen (which cost > SGD 20,000 in 2004) to look at the pictures. When the doctor looks at the pictures in his clinic it is usually on a much smaller computer monitor (costing < SGD 1000 in 2007). Will the clinic doctor be able to see all of the finer details in the picture before he makes a decision on treatment options? What do you think?

When you next feel like throwing out your old chest X-ray film, perhaps you should stop and think first. It might just save you a lot of angst when your doctor, at some future date, asks you ‘Do you have an old chest X-ray film that I can compare this to?’

What is periodontal disease? The word periodontal comes from ‘peri’ which means around and ‘odontal’ which means tooth. Thus, periodontal disease means a disease around the tooth, aka gum disease. Bacterial infection (bacteria live in the plaque on the teeth) of the gum leads to inflammation of the gum, called gingivitis. The gum becomes reddened, swells and bleeds easily. The gum separates from the tooth giving rise to spaces between the tooth and gum, called pockets, which become infected. If gingivitis is left unchecked it can lead to periodontitis, inflammation of the gum and bone around the tooth. As the gum and bone become destroyed, the tooth becomes loose and can finally be lost.

The culprit causing periodontal disease is plaque.  Plaque is a sticky colourless film which forms on the teeth. Removing plaque by regular visits to the dentist helps but there are several factors which can adversely affect the health of your gums too. These include: smoking, poor nutrition, being a habitual teeth clencher or grinder, diabetes mellitus and a genetic predisposition to periodontal disease.

A recent publication from the Harvard School of Public Health looked at the association of periodontal disease and pancreatic cancer in 51,529 US male health professionals aged between 40 and 75 years of age (J Natl Cancer Inst 2007; 99: 171 – 175) who were followed up for 16 years. Compared with people with no periodontal disease, individuals with periodontal disease had a 65% increased risk of developing pancreatic cancer. This increased risk of developing pancreatic cancer is seen in smokers and non-smokers. The possible biologic mechanism giving rise to the increased risk may be a consequence of the chronic inflammatory process in the body set off by the periodontal disease.

Is the association of periodontal disease and pancreatic cancer unique? In the last decade or so, epidemiological studies have suggested that periodontal diseases are associated with increased risk of cardiovascular diseases. A Swedish study examined 3,352 patients with periodontal diseases and looked at the prevalence of myocardial infarction (MI, commonly known as heart attack) and hypertension (HT, high blood pressure) in these people compared to 902 subjects in the general population. In middle-aged individuals (aged 40 – 60 years), the severity of periodontitis was significantly associated with HT and MI (J Periodontol 2006; 77: 1173 – 1178). In the Coronary Event and Periodontal Disease (CORODONT) study reported from Germany, the researchers looked at the association of periodontal bacteria load and confirmed coronary heart disease (CHD) in 789 people (Arch Intern Med 2006; 166: 554 – 559). Those patients with CHD had a significantly higher periodontal bacteria load and the bacteria Actinobacillus actinomycetemcomitans in the periodontal pockets. In addition, the presence of CHD was also associated with an increased need for periodontal treatment.

For those who have an interest in finding out more about periodontal diseases, you might like to visit the website of the American Academy of Periodontology. Humm…, come to think of it I can’t remember when was the last time I made a visit to the dentist. Perhaps I should take more care of my oral health before it bites!

Google was founded by Sergey Brin and Larry Page in 1998. In a short period of just over 2 years as a public listed company on the US stock exchange, it has reached a staggering market capitalization of just over 80 billion dollars. Both founders, in their early thirties, are now billionaires and hold great sway in the digital industry.

Search engines allow anyone with an access to the internet to gain access to an ever increasing knowledge base. Google has become so popular as a search engine that millions of people looking for information preferentially perform a Google search. Indeed its popularity has allowed the word ‘Google’ to enter the English lexicon as a verb. A Google user has access to more than 3 billion articles on the world wide web. Its popularity permeates all sectors of society and has surpassed PubMed as the search engine of choice for retrieving medical articles.

Two doctors in Australia, after seeing a 16-year-old patient, told the father that they were uncertain of the cause of the condition. However, the doctors were bowled over when the father told them exactly what the diagnosis was and went on to give the doctors a small tutorial on the condition. The patient’s father had googled the symptoms experienced and found the correct diagnosis before getting to the hospital. As a result of this experience, the two doctors undertook a research project based on the question: ‘How good is Google in helping doctors to reach the correct diagnosis?’ (BMJ 2006; 333: 1143 – 1145). Using 26 cases from case records published in the New England Journal of Medicine (NEJM), they entered 3 to 5 search terms from each case description into Google to see if they could come up with the right diagnoses. They sifted through the first 3-5 pages of each search and decided on the 3 most likely diagnoses suggested from the search. They then compared this to the actual diagnoses recorded in the NEJM case record. Google searches came up with the correct diagnosis in 15 cases (58%). Not bad at all!

However, one has to be aware of the limitations of this approach. The ‘searcher’ is required to know which search terms to use in order to get a list of more specific ‘hits’. Since Google does not suggest ‘diagnoses’, the ‘searcher’ has to sift through the list of ‘hits’ and decide on which hit gives the most likely diagnosis. Both these pre-conditions depend on the ‘searcher’s’ knowledge base. Google searches will therefore be more accurate if the conditions have specific symptoms and signs that can be easily used as search terms. A Google search is less likely to be successful in complex conditions with non-specific symptoms or conditions with unusual symptoms and signs.

As an exercise, I googled the terms ‘abdominal pain, nausea and vomiting’ to see what conditions could give rise to these symptoms. The search returned about 1,320,000 hits! (In comparison, it is estimated that physicians carry 2 million facts in their head to fulfill their role as a diagnosticians.) The first site on this list, MedlinePlus Medical Encyclopedia, was very general and gave 20 possible diagnoses with relevant hyperlinks to sites explaining each condition. The second site, familydoctor.org from the American Academy of Family Physicians, had a flow chart which the reader can ‘walk through’ with the ability to diagnose different common conditions which could give rise to abdominal pain, nausea and vomiting.

Indeed the internet is a huge resource and can help tremendously. It requires each user to have some education, knowledge and time in order to sift through a huge amount of information before coming to possible answers. The internet will continue to have a significant impact on our daily activities and one day it will become more ‘intelligent’ and make our search for information easier, more effortless and even more accurate. Of this I have no doubt.