Anyway, this is one example of the importance of the work of radiographers. I've always likened radiographers as photographers and radiologists / doctors, the film critic. Should radiographers mess up with their exposure factors and produce suboptimal images, no eagle eyes of the radiologist can pick up subtle abnormality.
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Wednesday, June 8, 2011
Quality matters
Anyway, this is one example of the importance of the work of radiographers. I've always likened radiographers as photographers and radiologists / doctors, the film critic. Should radiographers mess up with their exposure factors and produce suboptimal images, no eagle eyes of the radiologist can pick up subtle abnormality.
Big heart
1. False positive as in patient with pectus excavatum.
2. Pericardial effusion due to various causes.
3. Cardiomyopathy.
4. Valvular heart disease.
5. Ventricular aneurysm.
6. Mimickers: paraspinal mass or mediastinal mass.
Therefore it is important that adequate history is provided to the radiologist to come to a sensible conclusion.
The picture above shows an obvious enlarged heart which is due to congestive heart failure.
In order estimate the heart size (or cardiothracic ratio/CTR), it is important that the patient take a full breath to fully expand the lungs. Radiographic assessment can be made to assess if the lungs are indeed adequately expanded. A general rule of thumb is that the heart size should not be more than half the width of the greatest transverse diameter of the chest. Nonetheless this is only a rough estimate and should be correlated with the clinical presentation and other tests (eg. echocardiography, ECG etc.).
Some studies have also recommended that CTR of 0.55 to be considered normal for Asia pacific population due to smaller body habitus in this group of people.
Anterior knee pain in a young patient
This young patient presented with pain in the region of tibial tuberosity region. He is active in school and participated in a number of sports activity.
Can you spot the abnormality marked with the arrow?
The lateral knee radiograph shows separation of the ossicles from the ossification centre of the tibial tuberosity. One may also seen soft tissue thickening anterior to the tibial tuberosity.
The diagnosis is Osgood Schlatter disease. It is ne of the most common causes of knee pain in the adolescent. Consisting of pain and edema of the tibial tubercle (and hence this is an extra-articular disease), Osgood-Schlatter disease is generally a benign, self-limited knee condition associated with traction apophysitis of the tibial tubercle due to repetitive strain on the secondary ossification center of the tibial tubercle.
The aetiology of the condition is thought to be due to bone growth which is faster than soft tissue growth, resulting in muscle tendon tightness across the joint and loss of flexibility.
During periods of rapid growth, stress from contraction of the quadriceps is transmitted through the patellar tendon onto a small portion of the partially developed tibial tuberosity. This may result in a partial avulsion fracture through the ossification center. Eventually, secondary heterotopic bone formation occurs in the tendon near its insertion, producing a visible lump. Approximately 25% of patients have bilateral lesions.
Treatment is conservative with immobilization and steroid injection for symptomatic relief.Possible complications that can follow include nonunion of bone fragment, patellar subluxation, chondromalacia, avulsion of patellar tendon, genu recurvatum.
Friday, April 29, 2011
Soft tissue calcification
Motion artifact on MRI
Incidental finding on CT brain
Big heart
Implant assessment
Avulsion fracture
Another pertinent finding in the radiograph above is the opacification of the infrapatellar (Hoffa) fat pad which indicates presence of knee effusion.
Soft tissue tumor
Calcific bursitis
Not all opacities are pathological
Picture below outlines the opacity for you.
Hip pain
Another common cause of AVN includes steroid therapy. However, up to a quarter of patients with AVN have no identifiable causes.
Limitation of plain radiography in bone infection
A young diabetic man presented with chills, rigors and proximal calf pain for 1 week duration. Local palpation revealed local tenderness in the knee area, particularly at the proximal tibia. Plain X-ray (above) shows small area of ill-defined lucent area in the metadiaphyseal region of the proximal tibia. There was no periosteal reaction noted. No obvious soft tissue abnormality.
MRI of the calf shows massive area of marrow oedema involving the proximal tibia as shown in the image above (coronal STIR sequence).
The imaging diagnosis is early osteomyelitis.
This case illustrates the sensitivity of MRI in detecting early bone infection. As with other diagnoses, early detection afford early intervention which limits the resultant damage.
Bronchial abnormality on imaging
Elderly man with productive cough. Chest X-ray shows non-tapering peripheral airway dilatation along with peribronchial thickening.
These findings are consistent with that of bronchiectasis.
Plain radiograph can pick up late disease as per this case. Early bronchiectasis may be elusive of plain X-ray. HRCT thorax is the modality of choice in demonstrating bronchiectasis with greater sensitivity.
Picture above is the HRCT of another patient showing bronchiectasis with additional finding of peripheral honeycombing and subpleural fibrosis due to idiopathic fibrosing alveolitis.
HRCT (high resolution CT scan) of the thorax is a special protocol for examining for airway and interstitial diseases involving the lungs. In this technique, non-overlapping, thin collimation of the primary beam with high resolution algorithm are used. This protocol is different from the typical CT thorax which may not be able to demonstrate interstitial disease as clearly as HRCT.
Cost of running the medical imaging department
I used to have some doubts myself about how medical centres charge patient for imaging studies, which at times may seem like a lot. For e.g. an MRI of the joint typically costs around RM600-RM800.
After having worked in a private healthcare facility for a couple of months, I am beginning to appreciate the cost “behind” operating these mega machines.
To start with, the scanners usually cost about RM1 to 2 million. Renovation of the room is another 100 – 300 thousand ringgit. On top of that the annual service contract is typically about 5-10% of the cost of the machine. Some of the accessories used are non-serviceable (i.e. they are replaced if they are found to be faulty and cannot be fixed).
Featured in this article is the image of an MRI coil which was faulty recently producing images with a dark band on the right side. Unfortunately the coil’s warranty period has lapsed and it is non-serviceable. The construct of the coil looks simple enough with outer casing made of fiberglass material, few stripes of steel films, coils, transistors and cables. Guess how much this coil cost? A whooping RM50,000.00!
Considering all these additional costs, what patient pays may not even be enough to cover the initial and maintenance costs. But such is the nature of running the imaging department. We provide support to the clinicians who can in turn decide the best way to manage the patients.
Friday, April 22, 2011
Shoulder Bursitis
MRI of a middle-age lady with painful shoulder and reduction of range of movement suspected of rotator cuff disease. MRI showed fluid within the subcoracoid bursa, which in this case, communicates with the subdeltoid/subacromial bursa. The rotator cuff tendons and muscles are unremarkable. Labrum is intact.
In the absence of ratator cuff disease, finding of fluid in the bursae is suggestive of bursitis.
Communication between these bursae in the shoulder occurs in up to 20% of normal population.
Bursitis can be confidently diagnosed with correlation of clinical and imaging findings. For imaging, MRI is the recommended modality as it demonstrates the expected location of the bursae well and MRI is sensitive to increasing fluid present within these bursae.
Convenience and quality
Unfortunately as the study progressed, the bowel gas just kept on increasing to the extent that it almost obscure the view. Fortunately fast bolus injection of pre-warmed contrast was given, hence the concentration of the contrast excreted into the urinary system was sufficient to enable visualization of the urinary tracts beyond the bowel gas.
The lesson learnt in this case is the importance of fasting. Non-fasting patient can have increasing bowel gas which may obscure the opacified urinary tracts. It may not be justifiable to sacrifice quality for convenience. But when it comes to answering important clinical questions, exceptions may need to be made, as per this case.
Fatty Liver Disease
A growing concern for liver health due to the fast food and sedentary lifestyle era is a condition called hepatic steatosis (fatty liver). In this condition, large vacuoles of triglyceride fat molecules are accumulated within the liver cells (hepatocytes).
Other causes of fatty liver include:
Alcohol
Diabetes mellitus
Obesity
Steroids therapy
Chronic viral hepatitis
Chemotherapy
In some people, fatty liver can progress to inflammation of the liver cells (steatohepatitis) and even resulting in scarring of the liver (cirrhosis) and cancer formation (hepatocellular carcinoma). The long term harmful effects of fatty liver has just be discovered in the last decade through various clinical studies.
Fatty liver can be detected using ultrasound scanning of the abdomen. Normal liver has sharp edges with relative dark appearance (low echogenicity) as shown here in the images with blue arrow. However, patients with fatty liver will demonstrate bright liver (high echogenicity) as shown here in images with red arrows. Occasionally, the liver can be swollen as well (hepatomegaly) giving rise to epigastric discomfort.
Fortunately fatty liver is a reversible condition. The importance lies in early detection of disease and close follow-up with biochemical profile (liver function tests).
Wednesday, April 20, 2011
Breast Imaging: mammogram or ultrasound?
The breast can be investigated using a few methods, which include ultrasound, X-ray (mammography), MRI and thermography. At the moment, breast ultrasound and mammography remain as the main modalities frequently used.
So how does one choose which one to go for?
Women undergoing asymptomatic screening for breast cancer should undergo mammography as the first line. This is because mammography can detect microcalcifications as seen in DCIS (ductal carcinoma in situ), an early manifestation of breast cancer. DCIS can turn into invasive cancer in up to 50% of patients within the period of 10 years.
Ultrasound on the other hand, cannot pick up microcalcifications as good as mammography.
During mammography, another important finding is presence of a mass. If a mass or nodule is detected, it will be shown as a "white" shadow. Mammography can assess the margins of the lesion, the degree of 'whiteness" (density) of the lesion, presence of spicules, architectural distortion.
However, some women have very dense breasts, i.e. very thick glandular tissue. Hence the normal glandular tissue can obscure the mass lesion as both normal glandular tissue and mass lesion appear as white area on mammogram. Therefore patient with dense breasts (Bi-Rads category 3 and above) are routinely offered complimentary ultrasound to exclude mass lesion. Dense breasts do not hide the microcalcifications on mammogram, thus is not a concern for missing DCIS.
Picture on the left is a Peruru Mammography Unit which the centre currently owns and operates. It has won gold prize in Good design award in 2007 due to its ergonomic design and the patient comfort it provides.
Example of a mammogram. Arrow points at a well defined mass lesion which turns out to be a benign neoplasm (fibroadenoma)
Tuesday, April 19, 2011
Hysterosalphingography (HSG)
HSG remains one of the few techniques which is used to evaluate the patency of fallopian tubes.
It is a simple office procedure done by radiologist using aseptic (sterile) technique which involves insertion of a small sized Foley's catheter into the uterine cavity, followed by introduction of water soluble contrast media into the uterine cavity, thence the patent fallopian tubes and finally into the peritoneal cavity.
The procedure is routinely done during day 4 to day 10 following the cessation of the menses. Patients are required to fast overnight from solid although fluid restriction is not necessary. Patients with documented prior allergy or atopy (e.g. asthma) are routinely premedicated with oral prednisolone with dosage of 40mg 12 hours and 40mg 2 hours prior to the study to avoid contrast adverse reaction. Following the study, pelvic discomfort akin menstrual pain is experienced by some women. Cervical manipulation may induce vasovagal reaction in some, so patients should be accompanied by the partner or some company. If contrast fails to pass through the cornu, IV hyoscine may be administered to induce smooth muscle relaxation. Patients are also advised to bring sanitary pad as spotting due to cervical manipulation is common.
Second picture shown here is an example of a normal HSG where both tubes are normal in caliber and there is spillage of the contrast into the peritoneum indicating patency of the fimbrael ends. Abnormal findings which can be diagnosed via HSG includes blocked tube, hydrosalphinx, abnormality of the uterine cavity (uterine synechiae, endometrial polyp or fibroid) or congenital abnormality of the uterus. All these abnormalities can present as risk factors for infertility.
HSG is provided by this centre via strict appointment basis only.