question marks remain about its accuracy. According to a medical textbook on CT and MRI, many initial reports that MRI gave more detailed images than CT were ‘overly optimistic’. All the initial fanfare, which came from individual cases of patients, could not be confirmed by subsequent larger studies using full scientific methods. The earlier studies turned out not to be well controlled.100
Lately, MRI has shown to be less than accurate in detecting early prostate cancer101 or coronary artery disease.102 It is now thought that MRI is better than CT for the brain and spine, because of its ability to take shots of the top of the head and front of the skull and to detect subtle tissue changes, but CT is better for studying any sort of trauma – such as blows to a body part – or the bones or calcium.
The problem is that no one yet knows the likely long-term effects of subjecting the body to a magnetic field powerful enough to send magnetic objects flying across the room. So far, the National Radiological Protection Board has sounded a warning about the heating effects of the magnetic field and its ability to influence magnetic matter inside the body or to damage tissues.
Microbiologist Wendell Winter and colleagues at the University of Texas Health Center at San Antonio stated that exposure to these types of electromagnetic fields may not be totally harmless. They subjected a number of living things to a range of electromagnetic fields and found that they stimulated the growth rate of cancer cells.103
Research on chick embryos has demonstrated that they are at risk with the increased temperatures; female mice chronically exposed showed changes in their white blood cell count. Other animal studies show that MRI can cause birth defects in the eyes104 and damage to the ears.105 In the States, several patients with pacemakers died when the magnetic forces altered them.106
Another potential danger concerns any metallic substances on your body. Complications can occur if you have any metal prostheses or implants, surgical clips or artificial heart valves, you are wearing any metal object, like a watch, have any metal on your clothing, wear a shade of eye shadow that contains metallic substances or even have your ATM card in your wallet.
One of the big problems with MRI scannings is claustrophobia. Up to one-third of patients given MRI scans have felt so claustrophobic that the tests had to be abandoned.107 ‘After an MRI scan for my neck, I had appalling claustrophobia (during it), with memory loss,’ writes Jill from Aberdeen. ‘I kept crying, shaking, couldn’t write, stammered, had nightmares for two weeks afterwards. It was 55 minutes of hell – worse than the two previous CAT scans. It must affect the brain cells with all that magnetism.’
Perhaps the most unsuspected problem caused by radiofrequency fields of MRI is localized heating, a risk that is magnified among babies or patients who are anaesthesized.108 For instance, in one poll of 10 US American departments of radiology, the overwhelming majority of serious injuries relating to MRI imaging were burns.109 This heating can also cause future fertility problems in men, since sperm are rendered sterile if heated up to body temperature. One study found that average scrotal skin temperature was significantly raised by an average of 2°C, with the highest change 4°C.110 Four separate studies support Jill’s contention that the technique causes memory loss.111
The National Radiological Protection Board concludes that a magnetic field of 2.5 tesla (T) is safe for all patients. Between 2.5 and 4 T, evidence of harm is doubtful, but from 4 T upwards, likely to occur.
If you are pregnant, have a pacemaker or have a metal prosthesis such as an artificial hip, retained shrapnel or cochlear, carbon-fibre implants, you should avoid MRI. Implants in particular can either move or become foci for the heating effect of MRI, causing discomfort and local tissue damage. Besides the dangers of metal inside your body, every metallic object in the scanning room becomes a potentially lethal missile once the MRI device is turned on. The most serious reported injury with MRI occurred when an oxygen tank near the magnet started flying and struck a patient’s face.112
Doctors are also increasingly worried about the contrast agents used for all the ‘nuclear’ imaging techniques.
Of all the reports made to the UK Adverse Reaction Reporting Scheme in the six years between 1977–83, nearly half concerned methylene diphosphonate for bone imaging and one-third concerned colloids for liver scans. The majority of complaints concerned hypersensitivity to the dyes. The most conservative estimate is one in 1,000 people react – a figure far higher than originally believed.113
If your doctor wants you to undergo the procedure you should make sure he first takes your full medical history, since the protocol for using MRI differs depending on what you are investigating. According to multiple sclerosis specialist Dr Patrick Kingsley, when diagnostic toys like MRI weren’t available, any reasonably experienced neurologist could make a confident diagnosis of MS based on a patient’s symptoms and history. The only reason perhaps to proceed with an MRI scan is if the neurologist wishes to rule out a brain tumour which might be amenable to surgery.
LAB TESTS
Besides x-rays, laboratory tests of all persuasions are subject to the grossest sort of error. The Centers for Disease Control and Prevention in Atlanta, Georgia, studied a representative sampling of laboratories all over the US and found that about a quarter of all tests had incorrect results.114
An editorial in The Lancet once concluded that many routine laboratory diagnostic tests are a waste of time and money.115 This includes blood counts and biochemical screening when you’re admitted to hospital. One study, it said, showed that the illnesses of only six out of 630 patients were diagnosed from routine blood and urine tests. In another study of over 1,000 patients in an adult psychiatric unit, routine blood and urine tests contributed to less than 1 per cent of diagnoses; nearly three-quarters of diagnoses were made on the basis of the patient’s medical history or a physical examination.116
Doctors can’t even agree on blood sugar levels in people with diabetes.
A Scottish study found marked differences in the results between the two tests – one which measures carbohydrates in the blood, the other, just glucose – used to assess control of blood sugar levels and whether good blood sugar control has been achieved.117
THE HIV TEST
The most shameful instance of an unreliable lab test used for diagnostic purposes is the AIDS test. The enzyme-linked immunosorbent assay (ELISA) test is most frequently used to test your HIV status, and is usually considered proof-positive that you are infected with HIV. A test called Western Blot is often used as a confirmation. For the ELISA test, a sample of the patient’s blood is added to a mixture of proteins. It is assumed that if HIV antibodies are present in the blood, they will react to the HIV proteins in the test.
The proof that HIV causes AIDS hinges entirely on the idea that detection of an antibody response to the virus is proof of its actual presence. Doctors assume that if your body has made antibodies specific to HIV, it must mean that a protein of the virus – and so the virus itself – is present. In other