Monitor displays in radiology: Part 2.

Monitor displays play an important role in modern radiology practice. Practicing radiologists need to be familiar with the various performance parameters of medical-grade displays. A certain amount of technical knowledge is useful when making purchasing decisions since the right choice of equipment can have a great impact on the accuracy, efficiency, and speed in the radiology department.

Non Surgical Management of Pseudoaneurysms.

BACKGROUND: The incidence of pseudoaneurysm has increased due to the large number of vascular procedures performed and the widespread use of anticoagulation therapy during procedures. Non-invasive methods for management of pseudoaneurysms comprise of ultrasound guided compression (USGC), thrombin therapy, arterial embolisation and endovascular stent graft insertion. We discuss our experience in the management of fourteen cases of pseudoaneurysms using non surgical techniques. METHODS: During a two year period, fourteen patients presenting with pseudoaneurysms of different regions were treated. RESULT: Of the fourteen patients, eleven were iatrogenic and three were attributable to trauma. There were six cases of pseudoaneurysms of the femoral artery following coronary angiography studies. One patient developed pseudoaneurysm of right popliteal artery after external fixation of fracture right tibia and fibula. Three cases of renal artery pseudoaneurysms occurred following percutaneous nephrolithotomy (PCNL). The cases were evaluated using a varying combination of color doppler, multidetector computerised tomography (CT) and angiography. These cases were treated with ultrasound guided compression (USGC), stent graft and coil embolisation. The selection of method was based on the location and size of pseudoaneurysms besides the efficacy of the technique. USGC was performed in seven, of which six were in the femoral artery and one supraorbital. The technique was unsuccessful in three of the seven, wherein stent graft was deployed in the femoral artery. Coil embolisation was utilised in three cases of renal artery pseudoaneurysms following PCNL. CONCLUSION: Follow up with color doppler and CT angiography within a week, 6 and 12 months period showed successful regression of pseudoaneurysms in all cases.

Multidetector CT Evaluation in Arterial Stenting.

BACKGROUND: Multidetector CT (MDCT) represents breakthrough in CT technology, significantly improving CT Angiography applications. METHODS: Twenty one patients with aortoiliac & branch aneurysms or stenosis were evaluated by Digital Subtraction Angiography (DSA) and Multidetector CT (MDCT) before and after endovascular repair. RESULTS: There were eight cases of aortic & branch aneurysms and 13 with stenosis. Four cases had aortic aneurysms, while one case had left subclavian artery aneurysm, thoracic aneurysm, femoral and popliteal artery pseudoaneurysms. Of the 13 cases with stenotic lesions, iliac stenosis was seen in eight patients. The others included carotid, vertebral, aortic, renal and aortic bifurcation stenotic. MDCT offered accurate information on shape and size of aneurysm, shape and patency of graft, the presence or absence of perigraft thrombosis or endoleaks, while in stenotic lesions it provided useful information on shape of graft, its location, its patency and the presence and quantity of distal flow. CONCLUSION: MDCT was found to be a potentially useful modality during initial evaluation and follow up of patient undergoing endovascular repair.

Virtual Scopy with Multidetector CT.

Virtual scopy is a computerized, non-invasive technique used in simulating views provided by a fiber optic endoscope. Multidetector CT (MDCT) enhances the technique of Virtual scopy, by its z-axis resolution, faster data acquisition and improved 3D-image quality. The common application included Virtual Colonoscopy, Bronchoscopy, Gastroscopy, Angioscopy, Labyrinthoscopy, Thoracoscopy and Stentoscopy. Of the 45 Virtual scopies referred to Radiology Department at INHS Asvini, the single largest application was Virtual Angioscopy followed by Stentoscopy and the smallest was evaluation of larynx, labyrinth, colon and mediastinum accounting for 3 each. Endoscopy data and histopathological diagnosis was available in 17 patients, who underwent Virtual studies of larynx, airway, stomach, mediastinum and colon.

Cardiac MRI in Congenital Heart Disease - Our Experience.

A significant recent advance that has occurred world over in the continuously evolving field of Magnetic Resonance Imaging (MRI) practice is the introduction of Cardiac applications. Cardiac MRI has moved to the centre stage of clinical management strategy by non-invasively imaging the structure as well as function of the heart. It has a wide range of specific applications such as delineation of morphological anatomy, quantification of flow and pressure across cardiac valve dysfunction, evaluation of myocardial function, assessment of infarcts, mapping coronary arteries and so on. Evaluation of congenital heart disease (CHD) is an important application of Cardiac MRI since the morphological details of chambers, septum, defects and anomalous connections are depicted accurately. Besides, flow information across valves, chambers, outflow tracts and shunts are also provided. This article describes our experience in the use of cardiac MRI in congenital heart disease.

Impact of Multidetector CT on 3D CT Angiography.

3D Computed Tomographic Angiography (CTA) is a noninvasive volumetric imaging technique increasingly used for evaluation of vascular system. The introduction of Multidetector CT (MDCT) has increased scanning speed, allowing shorter acquisition time, greater volume coverage and decreased contrast requirement while diminishing respiratory motion artifacts. Thin-slice collimation protocols are routinely used which generate isotropic 3D voxels that improve image quality. The ideal CTA study requires scanning at peak vascular enhancement for optimal opacification of arteries with separation of arteries and veins. MDCT has enabled complete lower extremity inflow and runoff studies with a single injection, as well as thin-section CTA covering the entirety of the Carotid arteries and Circle of Willis. Sixteen row MDCT has increased scanning speed further facilitating the development of novel applications such as coronary CTA. CTA when perfomed with MDCT offers a "one scan - many views" option useful in imaging vascular diseases. CTA has important advantages over conventional angiography, such as reduced risk, diminished time and better patient acceptance. With MDCT, 3D CTA is crossing vessel tortuosity and evaluation of vessel fragility.

Radiology Image Management in a Teaching Hospital Network Scenario: Initial Experience.

INHS Asvini has the distinction of emerging as the first Armed Forces Hospital with networked radiology images, sourced principally from a recently installed Digital Substraction Angiography (DSA) machine (Siemens Polystar Top 1000 MA). In recent times, newer imaging machines offer digital images that are in DICOM format. DICOM denotes 'Digital Imaging and Communications in Medicine". Image management at INHS Asvini, involves transfer of DSA images in DICOM format, their conversion into Joint Photographic Experts Group (JPG) format and subsequent transmission of JPG images through a robust networking system that connects all departments/OPD/Wards, facilitating direct access of images to a variety of specialists and specialities. Clearly, this encouraging outcome is a small but useful step heralding the concept of 'anytime anywhere' images, and has the scalable expansibility of including CT and MRI images in future.

MAGNETIC RESONANCE IMAGING IN INTRACRANIAL TUBERCULOSIS.

UNLABELLED: Tuberculosis (TB) is still a major cause of serious illness in many parts of the world. Intracranially, TB manifests itself variably as meningitis, tuberculoma and tubercular abscess [1]. Although its appearance on MR is not absolutely specific, it is important in the proper clinical setting to recognize the range of possible patterns that can be observed on images [2]. Magnetic Resonance Imaging (MRI) has emerged as a quality imaging tool aiding in the diagnostic evaluation of intracranial TB variably displaying meningeal, parenchymal, osseous and craniovertebral lesions. The MRI characteristics of 18 cases of intracranial TB were reviewed. RESULTS: Multiple lesions occured with a slightly higher incidence at 61%. In all, 11 patients (61%) presented with meningitis. Meningeal lesions without parenchymal or vascular involvement were seen in 16% of cases. 2 patients had extension of enhancing exudates into the spinal subarachnoid spaces. While 6 patients had focal intra-axial tuberculomas, representing 33% cases, 3 patients presented with infarcts. 1 patient presented with haemorrhagic infarct at right middle cerebral artery territory while two other showed multiple small infarcts. Hydrocephalus was identified in 4 patients and epidural lesions were noted in 2 cases. MRI should be considered as the imaging modality of choice for patients with suspected intracranial TB.