MRI & molecular imaging

Continuing to talk about nanotechnology....there is a new study from Robarts Research Institute, where after injecting nano iron oxide particles, the researchers were able to use MRI to image circulating inflammatory cells that went on to infiltrate the brain and produce perivascular cuffs, in rats. This will help in predicting the occurrence of lesions in multiple sclerosis.

Eventually this form of molecular imaging will become common in the brain, heart and oncology both for early diagnosis as well as monitoring response to treatment.

Magnetic resonance force microscopy

Nanotechnology is big news these days. IBM scientists have developed an MRI scanner that can now detect signal from a single unpaired electron. Unlike body imaging, where we look at clusters of protons to produce signal and images, this technology uses a 3D microscopy technique to detect the tiniest of signals in a single atom.

This has tremendous implications for molecular manipulation and nanotechnology as a whole. I am not sure though, how this will impact MRI technology as applied to human diseases.

Pediatric neuroradiology CME

There is a half-day CME on Wednesday 11 August 2004 on Pediatric Neuroradiology to be conducted by Dr. Manu Shroff from Toronto, Canada. He will be speaking on 1) CNS infections in children and 2) Neonatal MR/CT neuroimaging and then conducting a Pediatric Neuroradiology quiz for about 2 hours.

The CME will be held from 2.00PM to 6.00PM at KEM Hospital in the MLT. Prior registration is free, but compulsory. Spot registrations will be charged a token Rs. 100.

The registration form will be up on Monday.

8th Residents' Review Course - Registrations active

The registrations for the 8th Residents' Review Course are now active.

Please read the instructions carefully. The registration form should be filled up online only if the payment is being made by credit card. Otherwise, please download the form or print it and send it by mail with a demand draft.

New guidelines for cholesterol levels

There are now new cholesterol guidelines, spearheaded by the American Heart Association and published in the recent issue of Circulation.

Basically, the recommendation is to get the LDL levels down to below 70. A lay explanatory news report of these guidelines explains the indications succintly. Statins along with life-style changes (exercise, proper food habits) are recommended for getting the cholesterol levels down.

Considering that most of us as radiologists are as good as lay people regarding these issues, there is an extremely simple article explaining issues related to cholesterol and methods of reducing LDL levels.

Imaging in rheumatoid arthritis - USG & MRI - two articles

For those specifically interested in this subject, there are two articles in the July issue of Arthritis Rheum.

One article by Szkudlarek M et al compares the role of USG in the evaluation of MCP joints in patients with RA using MRI as a gold standard. Their conclusion: "US enables detection and grading of destructive and inflammatory changes in the MTP joints of patients with RA. By comparison with MRI, US was found to be markedly more sensitive and accurate than clinical examination and conventional radiography. Considering the early and frequent involvement of the MTP joints, evaluation of these joints by US may be of major clinical importance in RA".

Some of our rheumatologists have been trying to use USG for this purpose; the only problem is that it is a tedious procedure and takes a lot of time.

The other article is even more interesting. Ostendorf B et al performed hand and wrist MRI scans on 25 patients with early RA. Those who had normal studies (10/25) had an MRI of the dominant foot. All these were abnormal. Their conclusion therefore is "RAMRIS analysis of MRI scans of the forefeet detected synovitis and bone edema in patients with early RA in whom MRI of the finger joints was normal. MRI of the forefeet contributes an additional tool aimed at earlier and more accurate diagnosis and thus might allow an earlier decision to start appropriate medication in patients with early RA."

This again adds to the growing literature on the use of MRI for the diagnosis and staging of patients with RA. Though not yet accepted by rheumatologists in our country (cost, etc), MRI of the hands and wrist with contrast allows both the early and accurate diagnosis of RA as well as prognosis and follow-up. MRI is currently the gold-standard in drug trials for assessing response to treatment.

Breast MRI in local staging of cancer

Coming on the heels of the presentation by Schnall et al at the recently concluded Association of Clinical Radiology meeting, is another article in European Radiology that describes the utility of pre-operative contrast-enhanced breast MRI for local staging.

Their approach is interesting. They compared the recurrence rates in patients who had (Group A) and did not have (Group B) pre-operative breast MRI for staging.

"All patients had histologically verified breast cancer and follow-up for more than 20 months (mean time group A: 40.3 months, group B: 41 months). Both groups received the same types of treatment. The in-breast tumor recurrence rate in group A was 1/86 (1.2%) compared to 9/138 (6.5%) in group B. The rate of chest wall recurrences was 12/35 (34.3%) in group A vs. 44/87 (50.6%) in group B. Contralateral carcinoma were detected within follow-up in 2/121 (1.7%) in group A vs. 9/225 (4%) in group B. All results were statistically significant ( P<0.001)."

The authors are convinced of the need for pre-operative breast MRI for local staging prior to surgery.

More and more pre-operative contrast-enhanced breast MRI will become a necessity especially if conservative surgery is being planned. This opens up one more major avenue for the growth of MRI referrals.

Incidental and small renal cell carcinomas - what happens to them if left untreated

There is an extremely interesting article by Wehle MJ et al in the July issue of Urology that describes the findings in 29 patients who could not have invasive management. These patients had enhancing masses less than 3.5cm in diameter.

"the average duration of follow-up imaging was 32 months (range 10 to 89). The average number of follow-up computed tomography scans was 4.9 per patient (range 1 to 11). The average width of the renal masses at diagnosis was 1.83 cm (range 0.4 to 3.5), and the average change in size per year was 0.12 cm for all patients. Four patients underwent radical nephrectomy because of growth of the renal mass (n = 1) or patient wishes (n = 3). The histologic findings in 3 of these 4 patients were consistent with renal cell carcinoma. Two patients underwent radiofrequency ablation of the masses. At last follow-up, metastatic disease had not developed in any patient, and no patient had died of renal cell carcinoma. Two patients had died of other causes"

Their conclusions are that "The results of our study showed that when comorbid conditions or patient wishes preclude invasive treatment, contrast-enhancing renal masses less than 3.5 cm wide that are suggestive of cancer can be safely managed with watchful waiting and serial computed tomography scans".

This is an interesting perspective to keep in mind in those patients who cannot or would not like to undergo surgery.

MSCT in patients with angina

There is a new article published this week in JACC comparing 16-slice CT at a 0.42ms rotation speed, with quantitative coronary angiography. The comparison was restricted to segments measuring more than 2mm in diameter. All patients were scanned only if they had a heart rate less than or equal to 70 and 66% of patients received a beta-blocker (100 mg metoprolol IV) 1 hr before starting the study.

In all these segments (usually around 10.9 per patient), this study found a 92% sensitivity for detection of significant lesions, a 95% specificity, a positive predictive value of 79% and a negative predictive value of 98%. These are the best results so far reported with this technology by any study.

There were 18 false-negative segments (out of 234). Fourteen were in non-calcified segments and the stenosis was underestimated. Thirteen of these were in the circumflex or in small side branches. Two were missed because of heavy calcification and two because of motion artifacts.

There were 58 segments that were incorrectly classified as significantly obstructed. Of these 26 and 17 were in heavy and moderately calcified segments respectively, and only 15 were in non-calcified segments. This means that in calcified segments, the sensitivity of picking up lesions is high, but it is likely that the stenosis may be overestimated.

Al these patients had stable angina. The authors rightly conclude that "multislice spiral computed tomography coronary angiography permits reliable detection of CAD in a population of patients in sinus rhythm and stable angina".

This is a landmark paper that establishes the role of 16-slice CT in the evaluation of patients with coronary artery disease. What we now know anecdotally is finally being corroborated by published data. However, even this article is old and was first submitted in December 2003. It is likely that with the increase in tube speeds last year, the results even on 16-slice scanners can be bettered. And with 64-slice scanners, coronary angiography with MSCT will probably become even better.

Consequences of silent stroke discovered using brain MRI in the elderly

There is an interesting article about the functional and cognitive consequences of silent stroke in the elderly. Schmidt et al show that in the elderly, silent strokes discovered on MRI, are associated with significant loss of cognition and function.

For those interested, the full text is available here.

Quiz answer - Musculoskeletal - Block 15 Quiz 1

The patient had a simple bone cyst that had fractured producing the "fallen fragment" sign. Most radiologists got the answer right. The answer is also available here.

The following radiologists got the correct answer:
Abhijeet Chury Akash Handique Alagappan S Amardeep Bhatia Amel Anthony Amit Jain Amritpal Singh Anil Kumar Dasyam Anjali Surjith Aravind K M Arun Thomas Ashwin Asrani Atul Aggarwal Avinash KR Avinash Munshi C Mahendran Chandramouli David Nucci Davis Chiramel Dayananda Deepa Viswanathan Deepak Goyal Dharmashi Bhate Gaurav Gupta Geetanjali Swamy Godwin Jeeva Hardeep Singh Indraneil Mekala Jagadeesh Jignesh M Modi Juliet R John K G Srinivasan K K Rastogi Karthik Ganesan Kelkar C M Kirti Khopkar Kirti Kulkarni Krishna Kiran S Lovneesh Garg M Srinivas Manoj John Manoj Mathur Meric Tuzun Miriam Buckley Mukesh Gupta N Eshwar Chandra Naveen Malay NBS Mani Neeraj Lalwani Nuri Karabay Prasad CSBR Prasanna Nagenahalli Puneet Bhargava R Rajakumar Raghavendra Bhat K Rajeev Garg Randall Varghese Ranjeet Narlawar Ravichandra G Razia Reshma Dalvi Sanila George Santosh Rai Sarika Pamarthy Shweta Bhatt Siddappa L Sindhu John Sith Phongkitkarun Sivasubramaniam Sonal Krishnan Sumit Seth T Sudarshan Tarun Pande Vivek Gupta VSS Gangadhar

Incidentally the new quiz this week is a fetal USG case.

Neuroradiologist booted from ACR for bad testimony in courts

The ACR has booted out a neuroradiologist from its organization for false and poor testimony as an expert witness for the plaintiffs in two separate cases. The ACR has been able to do this after a judgement in a previous case where the judge ruled that the American Association of Neurosurgeons was allowed to do the same to one of its members who gave bad testimony.

Luckily in our country, medicolegal cases, though on the rise are still limited in number and the amounts of money involved are still not as big as in the US. The IRIA however should set criteria for the behaviour and testimonies of expert witnesses on the lines of the ACR.

Chest case - fever & general weakness

At the Korean Chest Society site, there is an interesting case published three weeks ago. I won't spoil it by giving off the answer.

Information handling

Jud Gurney in his blog "Radiology Indications" has an entry from Sept 2003 on how to handle information for biomedical scientists. It has amazing information on how to access Hubmed feeds for articles, on bioblogging and other such topics, for those who are interested.

Prostate cancer - CPC

Last week's NEJM has an interesting CPC on advanced prostate cancer and its management. Unlike most CPCs, where the diagnosis is initially unknown and the expert has to come to a diagnosis, in this case, the diagnosis is known...it is essentially an update on the management of advanced prostate cancer. The role of radiology is discussed in quite some detail.

A brain MRI quiz

This is a multiple choice, multi-question quiz on a "brain" case, where the author stresses the point that it is necessary to require training in reading neuro cases. The patient landed up with a neurosurgeon with the diagnosis of a glioma - obviously that was not the diagnosis.

Recto-vesical fistula

Here are some really nice CT pictures of a recto-vesical fistula.

3D of the brain - a new method

There is a newsgroup called alt.image.medical in which a "lay" person has asked how a 3D photo of his brain could be obtained.

One of the doctors in the group has given a rather apt answer.

Outsourcing issues

Last week has seen some buzz about the NIH shipping blood and urine samples to India for analysis. Apparently the low cost of analysis in India offsets the shipping costs.

I wonder if this is also possible. If a flight were to be chartered with people requiring MRIs and CT scans, I wonder if the low cost of the studies in India would more than offset the cost of travel, as compared to the cost in the UK.

Typically, if you can get fares for around Rs 20,000 on a charter-flight and it costs around Rs 70,000 in the private sector in the UK to do an MRI and we charge around Rs 5,000 for an MRI, it could work. Just needs an entrepreneur with spunk.

Me and my MRI

The New York Times last week had an article on issues related to self-referral by David Levin, on the issue of self-referral to self-owned imaging equipment by non-radiologist physicians. The most important statement is "between 1993 and 1999, virtually all of the increase in Medicare use of imaging and the resulting costs were attributable to nonradiologist doctors who operate their own imaging equipment and are usually in a position to self-refer".

Another statement is as enlightening. 'A large health care insurance plan in one western state recently conducted inspections of 462 offices that provided imaging. More than one-third of the offices run by nonradiologists failed; of the offices of radiologists, only 1 percent failed".

Similar issues affect us as well in India. The number if non-radiologists putting up imaging equipment and using it is on the rise. Though we don't have proper statistics, I am sure there is cause for alarm. This is something the IRIA needs to focus on.

A twist of fate

There is an interesting clinical problem-solving article in one of the recent issues of NEJM. It gives details about a real-life emergency clinical situation and the way in which a diagnosis was finally reached. The diagnosis was finally reached with an MRI.

I don't want to spoil the surprise by giving out the diagnosis but the title does say it all.