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ABSTRACTS OF PAPERS PRESENTED AT THE 70TH RESEARCH MEETING OF THE MEDICAL RESEARCH CENTRE OF BOMBAY HOSPITAL ON MONDAY, 20TH SEPTEMBER 1999, 2.30 PM IN THE SP JAIN CAFETERIA (CONVENOR DR. HL DHAR)

1.VIRTUAL ENDOSCOPY : TECHNIQUE AND CLINICAL APPLICATIONS

Meher Ursekar, Inder Talwar, Meenakshi


Virtual endoscopy (or computed endoscopy) is a new method of diagnosis using computer processing of 3-D image datasets (such as CT or MRI scans) to provide simulated visualizations of patient specific organs similar or equivalent to those produced by standard endoscopic procedures. Conventional CT and MRI scans produce cross section "slices" of the body that are viewed sequentially by radiologists who must imagine or extrapolate from these views what the actual three dimensional anatomy should be. By using sophisticated algorithms and high performance computing, these cross sections may be rendered as direct 3-D representations of human anatomy. Specific anatomic data appropriate for realistic endoscopic simulations can be obtained from 3-D MRI digital imaging examinations or 3D acquired spiral CT data.

Thousands of endoscopic procedures are performed each year. They are invasive and often uncomfortable for patients. Virtual endoscopic visualization avoids the risks associated with real endoscopy, and when used prior to performing an actual endoscopic exam can minimize procedural difficulties and decrease the rate of morbidity, especially for endoscopists in training. Additionally, there are many body regions not accessible to or compatible with real endoscopy that can be explored with virtual endoscopy. Eventually, when refined, virtual endoscopy may replace many forms of real endoscopy.

The aim of this presentation is to describe the technique of virtual endoscopy obtained from spiral CT data, and to share our initial experiences with the technique. We have used this technique to evaluate the adult and paediatric airway and the paranasal sinuses. A discussion about potential clinical applications will be presented.


2.SPINAL CORD STIMULATION - A NEW FRONTIER IN TREATING NEUROPATHIC PAIN

D B Modi, N Pawar

Spinal cord stimulation has achieved pain relief and dramatic improvements in the quality of life for many people suffering from certain severe chronic pain conditions.

SCS is a pain treatment that delivers low voltage electrical stimulation to the spinal cord to inhibit or block the sensation of pain. The SCS system consists of a lead, which delivers electrical stimulation to the spinal cord; an extension wire, which conducts electrical pulses from the power source to the lead and a power source that generates electrical pulses.

The goal of SCS therapy is to reduce, not to eliminate pain.

Successful outcomes with SCS therapy require three elements.

The concept of SCS to treat intractable pain was based on the gate control theory of pain. Shealy and colleagues published the first article describing the relief of chronic pain by electrical stimulation of the spinal cord in 1967. This technique involved surgically implanting electrodes over the dorsal columns after laminectomy with the aim of activating pain inhibiting mechanisms and therefore was labeled dorsal column stimulation.

SCS offers effective pain relief for

Surgical Technique

Currently SCS method falls into two categories. The first involves implanting electrodes in the epidural space via laminectomy and subcutaneously connecting the electrode, leads to a radio receiver / transducer or a battery - powered pulse generator, usually placed in the anterior abdominal wall. The receiver / transducer is stimulated by an external powered transmitter, which operates through an antenna placed over the receiver. The patient can set the intensity, the frequency and the pulse width with the use of the transmitter. The battery powered unit can be transcutaneously programmed to alter a wide array of stimulation parameters, including electrode selection via a computerised telemetry system.

The second method involves the percutaneous insertion of electrodes into the epidural space. The lead form the electrodes may be connected to an external generator allowing a trial period of stimulation or it may be connected to an implanted receiver or a totally implanted pulse generator. When trial stimulation is used, if the test stimulation alleviates the pain, the receiver is internalised in the second procedure. The second procedure may be implantation of electrodes via a laminectomy or alternatively, the placement of the receiver in the subcutaneous pocket with lead from the receiver subcutaneously tunneled to the incision in the back and connected to the electrode after disconnection of temporary percutaneous lead. The patient can stimulate the radio receiver/transducer by an external transmitter or a fully implantable system internal battery may be used.

The implanted systems have varied widely. The first systems used monopolar electrodes and one channel of stimulator; a ground plate was also attached to the receiver/transducer. Stimulators are also available with quadripolar or octapolar electrodes. Multichannel programmable systems have also been developed and the range in stimulation parameters is large. Sophisticated stimulation envelopes, such as ramped and intermittent stimulation are also available.

Complications from SCS may be technical or biological. The most frequently reported technical complications are electrode dislocation, breakage and lead migration. The most frequently reported biological complications are infection, CSF leakage and pain at the incision, electrode or receiver site.

Results

Four patients have been implanted with this stimulator and have shown positive results. Enthusiastic inferences have drawn from a six month patient follow-up programme.


3.THERMOGRAPHY

Amitabh Gupta, S Yuwanti, DB Modi

Thermography or medical digital infrared thermal imaging (DITI) is a non-invasive diagnostic technique that allows the examiner to visualise and quantify changes in skin surface temperature. An infrared scanning device is used to convert infrared radiation emitted from the skin surface into electrical impulses that are visualised in colour on a monitor. This visual image graphically maps the body temperature and the referred to as a thermogram. The spectrum of colours indicates an increase or decrease in the amount of infrared radiation being emitted from the body surface. Since there is a high degree of thermal symmetry in the normal body, subtle abnormal temperature asymmetry's can be easily identified.

DITI's major clinical value is in its high sensitivity to pathology in the vascular, muscular, neural and skeletal systems and as such can contribute to the pathogenesis and diagnosis made by the clinician. This technique is unique in its capability to show physiological (functional) abnormalities and can graphically display and record the patient's 'subjective' feeling of pain by objectively displaying the changes in skin temperature that accompany pain states.

DITI will soon be recognised as a useful tool in the early identification of musculoskeletal and neurological injuries, especially non-specific (and difficult to diagnose) pain syndromes. The ability to detect inflammatory and neurological processes at a very early stage can be critical to the outcome. DITI also shows benefits in many areas of medicine including Woman's health where DITI provides adjunctive, non-invasive and painless early detection test for breast diseases. In sports medicine DITI is useful as a regular screening test to prevent serious injury and to allow training programmes to be amended before irreparable damage is done. Such early detection can significantly reduce the losses associated with training delays and prolonged recovery time. DITI can also provide information about patient's response to treatment as well as the effects of injury, disease or prescribed treatment.

All biological processes, movements, pathological changes etc., taking place in the human body are accompanied by specific temperature changes. Medical diagnostic methods have always placed great importance on the measurement of body temperature. Different methods are used to record the changes taking place in conjunction with fever, inflammation, cold nodes etc.

The human body can be viewed as a uniform energy system (thermally symmetrical) which continuously radiates heat in the environment. This heat is emitted in the form of electromagnetic infrared rays, which travel at the speed of light and can be detected by special infrared scanning devices. Skin blood flow is under the control of the sympathetic nervous system. In normal subjects (asymptomatic) there is a symmetrical dermal pattern which is consistent and reproducible for any individual. This is recorded in precise detail to a temperature accuracy of 0.01o C by thermography (DITI) and can be visualised and quantified.

I. Cardio-vascular system : Arteriosclerosis, carotid coronary insufficiency, superficial vascular disease, thoracic outlet syndrome.

II. Oncology : Breast diseases, neoplasia (melanoma, squamous cell, basal)

III. Neurology : Dystrophy, hyperaesthesia, headache evaluation, herniated disc, nerve trauma, neuropathy, neuralgia, neuritis, neuropraxia, peripheral nerve injury, peripheral axon disease, referred pain syndrome, reflex sympathetic dystrophy, stroke screening, sensory loss, sensory nerve abnormality, lower motor neuron disease, median nerve neuropathy, trigeminal neuralgia, somatic abnormality, neurovascular compression, somatisation disorder, Morton's neuroma, temporal arteritis, whiplash.

IV. General medicine : Inflammatory disease, infectious disease (Shingles, leprosy), nutritional disease (Alcoholism, diabetes), skin abnormalities.

V. General surgery : Deep vein thrombosis, grafts, soft tissue injury, Raynaud's syndrome.

VI. Orthopaedics : Brachial plexus injury, bursitis, carpal tunnel syndrome, compartment syndrome, causalgia, disc disease, disc syndromes, facet syndromes, herniated disc, herniated nucleus pulposis, hyperextension injury, hyperflexion injury, lumbosacral plexus injury, ligament tear, muscle tear, musculoligamentous spasm, nerve impingement, nerve entrapment, nerve pressure, nerve stretch injury, ruptured disc, Raynaud's syndrome referred pain syndrome, sprain/strain, synovitis, TMJ dysfunction, tendonitis.

Digital infrared thermal scans were conducted on patients referred by doctors from various specialities vis-a-vis orthopaedics, neurology, general medicine, physiotherapy, oncology etc. These tests were conducted over 60 plus patients over a period of three days. The findings were extremely useful and correlated with clinical diagnosis and X-rays (in few cases) and indicative in terms of further course of treatment and referral to a specialist.


4.MAMMOGRAPHY THE GOLD STANDARD IN BREAST IMAGING

Nitish Pawar, Anand Biwani, Poonam Khera, DB Modi

The widespread use of mammography and the rising awareness of media, clinicians and public has contributed greatly in reducing mortality and morbidity in patients with breast disease. The rising incidence of breast cancer and the sharing of concern publicly by clinicians and patients has brought breast cancer to the forefront as a leading health problem. The stark and sobering statistics of "one in nine" which refers to the chance that the woman will develop breast cancer in her lifetime demands that we pay more attention to this field.

Mammography is the tool with which we can effectively cope with this problem. It is a noninvasive, low dose imaging technique used widely for screening and diagnostic purposes. Dedicated mammography equipment available currently delivers exquisite resolution, consistent exposures and low radiation dosages which are extremely important in order to make the procedure safe and comfortable. Optimised compression and exposure techniques have reduced the discomfort and radiation dosage to a minimum.

Indications : Mammography is recommended as a baseline procedure for all women over 35 years. It should be followed by studies every two years in women between 40-50 years and yearly studies thereafter.

Women at greater risks are -

- Positive family history

- Those on HRT

- Multiparous women

As a screening procedure mammography reveals -

- masses

- calcifications

- architectural distortions

- ductal pathologies

- axillary lymphadenopathy.

Of all diagnosed breast lumps only 10% are malignant. Further characterising of these masses is required to avoid unnecessary biopsies and surgery. Towards this end high resolution. Sonography forms an invaluable and integral part of the examination. Masses can be separated into solid and cystic types. Cystic masses are less likely to be malignant and more amenable to aspiration and cytology. Other indications are young patients dense breasts, lactating engorged breasts, pregnant patients, acute mastitis, post radiotherapy and surgery and masses which cannot be placed within the field of mammography. However despite its obvious value being operator dependant time consuming and its inability to compare it cannot be used as a screening procedure. It is definitely well placed as a 'trouble shooter'. Its use for FNAC is undisputed.

FNAC / STEREO TACTIC GUIDED BIOPSY

The ability to obtain definitive diagnosis of breast lesions without surgery has changed the face of breast treatment. FNAC may be carried out by mere palpation, with ultrasound guidance and recently and more precisely by stereo tactic techniques both film and digital. Lesions as small as 5 mm can be targeted successfully.

EXPERIENCE

Approximately 300 patients have been evaluated so far. The maximum number of patients were in the age group of 40-50 years, the next larger group being 30-40 years. Most patients came for outine screening studies which was a very encouraging sign as it shows that there is rising awareness. There were approximately seven malignancies per 100 patients.

One stereo tactic biopsy was successfully done for a small suspicious lesion which was a benign lypofibroadenoma on pathology.


5.THYROID FUNCTIONS IN DIABETIC AND HYPERTENSIVE PATIENTS

D M Sharma, D R Jangid, S V Joshi, H L Dhar

This study was conducted to analyse thyroid functions in diabetic and hypertensive patients. Detailed clinical history was taken in 650 patients (F=480; M=170) reporting for thyroid function studies in nuclear medicine department. T3, T4, TSH were measured, blood sugar was estimated in diabetic patients while urea, creatinine, cholesterol and urine catecholamines were measured in hypertensive patients to exclude secondary hypertension.

Thyroid function was found within normal limit in 454 patients (69.85%), 70 patients were hypothyroid (10.08%), and 126 patients (19.38%) were hyperthyroid. However, 44 (6.76%) were diabetic, 61 (39.6%) were hypertensive and 30 (4.6%), were suffering from both diabetes and hypertension.

In normal subjects (454) average thyroid functions were T3-1.80 0.8 ug/ml, T4-96.03 8.6 ug/ml and TSH - 3.86 1.1 mIU/ml. In hypothyroid (70) thyroid functions were T3 - 1.21 0.67 ug/ml, T4 - 52.13 5.2 ug/ml and TSH - 8.19 2.18 mIU/ml in hyperthyroid subjects (126) thyroid functions were T3 - 3.29 1.0 ug/ml T4 - 178.4 8.3 ug/ml and TSH - 0.002 0.01 mIU/ml.

Mean blood sugar in diabetic patients was fasting - 150 20 mg/100 ml and post prandial - 248 25 mg/100ml. Biochemical profile in hypertensive patients were serum creatinine - 1.08 0.06 mg%, cholesterol - 195.86 5.24 mg%. Urea - 26.18 3.21 mg% and urine catecholamines - 309.5 5.96 ug/24 hrs.

No significant changes were seen in thyroid functions in hypertensive patients associated with thyroid disorders. However, significant decrease of T3 was documented in diabetic patients associated with thyroid disorders which could be due to decrease in the rate of conversion of T4 to both T3 and reverse T3 as well as decrease in the metabolic clearance rate of both triiodothyronines.


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