Ultrasound images of normal anatomy and appearances of fetal spine: *This 2-D, ultrasound image shows the sagittal section of the normal fetal spine in longitudinal section. (Image courtesy of Dr. Ravi Kadasne, UAE).
3-D Ultrasound images of normal fetal spine: *Sonography of fetal spine using 3-D/ 4-D ultrasound reveals greater detail of the fetal spine in 3-Dimensions. Ultrasound visualizes the ossified part of the fetal spine. The 3 main ossification centers in the fetal vertebrae are: a) the centrum b) the right neural process and c) the left neural process.
The centrum forms the central part of the vertebral body. The postero-lateral parts of the vertebrae are formed by the right and left neural processes. (These 3-D ultrasound images are courtesy of Dr. PK Srivastava, India, and Dr. Ravi Kadasne, UAE).
Primary mediastinal large B-cell lymphoma accounts approximately 5% of large B-cell lymphoma, which are usually disseminated or present in the abdomen. There appears to be a younger age of diagnosis (30s) and female predilection (F:M 3:2), when compared to other large-cell lymphoma, which usually present in the 50s and have a male predilection (M:F 2:1).
Unfortunately from an imaging point of view, these demographics are similar to those of nodular sclerosing Hodgkin lymphoma, which is a common cause of a primarily mediastinal lymphoma.
There Clinical presentation is usually due to the mass effect of the typically large anterior mediastinal mass. SVC compression resulting in SVC syndrome is relatively common, present in up to 35% of cases.
Radiographic features The vast majority of patients have an anterior mediastinal mass. Middle and posterior mediastinal involvement, either in isolation or contiguously with the anterior mediastinal component is uncommon.
Plain film Chest radiography demonstrates a soft tissue anterior mediastinal mass.
CT CT of the chest usually shows:
* soft tissue attenuating mass
* usually large at diagnosis ~10cm diameter
* mass effect common
bowing and compression of trachea
SVC obstruction : up to 35% cases
* cystic areas are common : up to 44%
* calcification pre-treatment is uncommon, but recognised
* chest wall invasion may occur
* pleural effusion(s) / pericardial effusion
seen in up to a third of cases
pleural effusion may be associated with poor outcome
“CT of the chest of 22 year old demonstrates a large mediastinal mass with significant external compression of the SVC. A moderately sized pericardi...”
Learn about mesothelioma treatment options via surgery from the International Symposium on Malignant Mesothelioma 2008. Presentation by Dr. Robert Kratzke.
How does a Chemical Stress (Isotope Stress) Test work? A chemical or pharmacological stress test combines an intravenous medication with an imaging technique (isotope imaging or echocardiography) to evaluate the LV. In these cases, the medication serves the purpose of increasing the heart load instead of using exercise. Stress causes normal coronary arteries to dilate, while the blood flow in a blocked coronary artery is reduced. This reduced blood flow may decrease the movement of the affected wall (as seen by echo), or have reduced isotope uptake in a nuclear scan. Agents that are commonly used in pharmacologic stress testing include dipyridamole, dobutamine and Adenosine (Trade name).
Indications of Chemical Stress Test ? Treadmill stress testing is the test of choice when a patient is able to exercise because of the physiologic effect that exercise has on the blood pressure and heart rate. It also helps give the physician an idea about the patient's exercise tolerance and whether or not exertion has any adverse effects on the patient's symptoms or irregular heart beats. Additionally, one does not have to contend with any potential side-effects of chemical stress, even if they are usually minor.
However, exercise may not be possible because of physical limitations like back trouble, joint disease, marked fatigue, unsteady gait, prior stroke, dizziness, shortness of breath, etc. In such cases, chemical stress testing is employed. In other words, pharmacologic or chemical stress test is performed in situations where patients are unable to perform more than moderate exercise due to severe arthritis, prior injury, reduced exercise tolerance (as a result of debilitating illnesses, etc.), or in patients who are unable to increase the heart rate (as in some with heart pacemakers or in the setting of certain diseases that keep the heart from speeding up).
Preparing for an Isotope Stress Test : The following recommendations are "generic" for all types of cardiac stress tests:
* Do not eat or drink for three hours prior to the procedure. This reduces the likelihood of nausea that may accompany strenuous exercise after a heavy meal. Diabetics, particularly those who use insulin, will need special instructions from the physician's office.
* Caution about asthma: The use of dipyridamole is generally avoided in patients with asthma. Please be sure to notify your physician if you have a history of asthma, bronchitis or emphysema.
* Specific heart medicines may need to be stopped one or two days prior to the test. Such instructions are generally provided when the test is scheduled.
* Wear comfortable clothing and shoes that are suitable for exercise.
* An explanation of the test is provided and the patient is asked to sign a consent form.
Is it safe? The patient is exposed to a very small amount of radiation and the risk is minimal, if any. The risk of the chemical stress portion of the test is very small and similar to what you would expect from any strenuous form of exercise (jogging in your neighborhood, running up a flight of stairs, etc.). As noted earlier, experienced medical staff is in attendance to manage the rare complications like sustained irregular heart beats, unrelieved chest pain or even a heart attack. In such cases, the patient is better off having the problem in the presence of experienced staff, rather than have it happen when they are exercising alone. Also, the stress medicine like Dobutamine can be immediately stopped if there are problems, The effects of dipyridamole (which can occasionally cause nausea or a headache can be reversed by aminophylline (an anti-asthma medication). Please also see the caution about asthma under the "Preparing..." section.
A giant cell tumours of the tendon sheath (GCTTS) is an uncommon usually benign lesion that arises from the tendon sheath. It is unclear whether these lesions represent neoplasms or simply reactive masses. The are also known as pigmented villonodular tumour of the tendon sheath (PVNTS).
Clinically these masses typically present in the hand (although they are found elsewhere also) with localised swelling with or without pain. They are slow growing.
Typically they present in 3-5th decades and have a slight female predilection with a M:F ratio of 1.5 -2.1:1 .
Distribution of GCTTS
Pathology They have been divided macroscopically into localised or diffuse forms, and appear as rubbery multinodular masses that are well circumscribed. They have an enveloping fibrous capsule, and the cut surface is variably coloured depending on the relative proportions of fibrous tissue, haemosidering and pigmented foam cells.
The tumour is histologically identical to pigmented villonodular synovitis (PVNS) and is composed of fibroblasts and multinucleated giant cells, foamy histiocytes and inflammatory cells on a background fibrous matrix.
Radiographic features Plain film As these masses arise from tendons, commonly of the hand, they may cause pressure erosions on the underlying bone. This is only seen in 10 - 20 % of cases. More commonly these masses arise from the palmar tendons. The mass itself is of soft tissue density. Calcification is uncommon. Ultrasound Ultrasound is useful as it allows not only characterization of the lesion but also is able to demonstrate the relationship with the adjacent tendon.
These masses are typically homogeneously hypoechoic, although some heterogeneity my be seen in echo-texture in a minority of cases . Most will have some internal vascularity.
Giant cell tumour of tendon sheath (Modality: Ultrasound)
MRI Not surprisingly, given the histological similarity to PVNS, giant cell tumours of the tendon sheaths also share the same finding on MRI, mainly on account of hemosiderin accumulation.
* T1 : o low signal o variable enhancement * T2 : low signal
The sphenoid bone carries its share of creating part of the base of the cranium. While it can be seen laterally and inferiorly, the shape of the bone is a bit unusual and is often described as moth or butterfly like. The butterfly shape looks very much like the body accompanied by the two wings which form the orbit. The “body” of the bone consists of the sphenoidal sinuses and the saddle shaped depression which is remarkably prominent. This is called the sella turcica. Commonly referred to as “Turk’s saddle,” this is where the pituitary gland resides. The lateral walls of the nasal cavity are assisted in formation by the inferior projection of pterygoid process. The sphenoid bone is associated with ample foramina properties.
The smaller portion of the “wing” in the rear of the skull helps create a large opening that allows the transfer of optic nerve passageway through the optic canal. The ophthalmic artery also transverses through this passageway. A triangular opening that can be found in between the “wings” associated with the sphenoid bone. This opening is known as the superior orbital fissure and is designed to allow the ophthalmic nerve safe passage to the eyes. The ophthalmic nerve is part of the trigeminal nerve. Additionally, the trochlear nerve, the oculomotor nerve, and the abducens nerve all travel through this same triangular opening.
The mandible nerve passes through an opening known as the foramen ovale. This small opening rests at the base of the lateral pterygoid plate. The rear angle of the sphenoid bone contains a small opening known as the foramen spinosum which allows the middle miningeal nerves to pass through the sphenoid bone. Between the sphenoid bone and the and the petrous part of the temporal bone, the foramen lacerum opens to allow the internal carotid artery as well as part of the ascending pharyngeal artery known as the meningeal branch to pass. The maxillary nerve makes its passage through the foramen known as the rotundum which is located just behind the superior orbital fissure.
*This 2-D, ultrasound image shows the sagittal section of the normal fetal spine in longitudinal section. (Image courtesy of Dr. Ravi Kadasne, UAE).
*Sonography of fetal spine using 3-D/ 4-D ultrasound reveals greater detail of the fetal spine in 3-Dimensions. Ultrasound visualizes the ossified part of the fetal spine. The 3 main ossification centers in the fetal vertebrae are:
