Computed Tomography (CT) is the mainstay of diagnostic imaging evaluation of thoracic disorders. However, there are a number of CT protocols ranging from a simple non-contrast CT at one end of the spectrum, and CT perfusion as a complex protocol available only on high-end scanners. With the growing diversity, there is a pressing need for radiologists, and clinicians to have a basic understanding of the recommended CT examinations for individual indications. This brief review aims to summarise the currently prevalent CT examination protocols, including their recommended indications, as well as technical specifications for performing them.

SummaryBackgroundTo evaluate the role of diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) values at 3 Tesla in characterizing sinonasal masses.Material/MethodsAfter ethical clearance, 79 treatment naive patients with head and neck masses underwent magnetic resonance imaging (MRI), including DWI at 3 Tesla using the following b values – 0, 500 and 1000 s/mm2. Thirty-one patients were found to have sinonasal tumours and were subsequently analysed. Image analysis consisted of a morphological evaluation of conventional MR images, qualitative evaluation of DW trace images and quantitative assessment of mean ADC values. Receiver operating characteristic (ROC) curve was drawn to determine a cut-off ADC value for the differentiation between benign and malignant masses.ResultsSinonasal masses showed an overlapping growth pattern on conventional imaging, irrespective of their biological nature. The mean ADC value of benign lesions was 1.948±0.459×10−3 mm2/s, while that of malignant lesions was 1.046±0.711×10−3 mm2/s, and the difference was statistically significant (p=0.004). When a cut-off ADC value of 1.791×10−3 mm2/s was used, sensitivity of 80% and specificity of 83.3% were obtained for characterization of malignant lesions, which was statistically significant. Juvenile nasopharyngeal angiofibroma (JNA) showed distinctly high ADC values, while meningioma was the only benign lesion with restricted diffusion. Atypical entities with unexpected diffusion characteristics included: adenocarcinoma, adenoid cystic carcinoma, meningioma, chondrosarcoma and fibromyxoid sarcoma.ConclusionsDWI in conjunction with conventional imaging can potentially enhance the diagnostic accuracy in characterizing sinonasal masses as benign or malignant. Some specific entities such as JNA and meningioma showed distinctive diffusion characteristics.

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Purpose:To evaluate the diffusion weighted (DW) magnetic resonance imaging (MRI) features of the extracranial schwannomas of head and neck.Materials and Methods:The MRI (including DWI) of 12 patients with pathologically proven head and neck schwannomas (4 men, 8 women, with mean age of 32.6 years; age range 16–50 years) were retrospectively evaluated. Images were analyzed for signal intensity and morphology on conventional sequences followed by the qualitative evaluation of DW images (DWI) and measurement of apparent diffusion coefficient (ADC) values.Results:Majority of the tumors were located in the parapharyngeal space (8/12). All but one showed heterogeneous appearance, with 10 tumors showing scattered areas of hemorrhage. Eight out of 12 tumors showed intensely hyperintense core surrounded by intermediate signal intensity peripheral rim (reverse target sign) on T2-weighted (T2W) images. On DWI, these eight tumors showed a distinctive appearance, resembling target sign on trace DWI and reverse target on ADC map. Out of the remaining four tumors, one showed uniformly restricted diffusion whereas three showed free diffusion. Mean ADC value in the central area of free diffusion was 2.277 × 10−3 mm2/s (range of 1.790 × 10 −3 to 2.605 × 10−3 mm2/s) whereas in the peripheral area was 1.117 × 10−3 mm2/s (range of 0.656 × 10−3 to 1.701 × 10−3 mm2/s). Rest of the schwannomas showing free diffusion had a mean ADC value of 1.971 × 10−3 mm2/s.Conclusion:Majority of the head and neck schwannomas showed a characteristic appearance of free diffusion in the centre and restricted diffusion in the periphery of the mass.

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Percutaneous biliary intervention encompasses diagnostic cholangiography, which is rarely used in isolation now, and therapeutic biliary drainage including percutaneous transhepatic biliary drainage and transhepatic cholecystostomy. With the advantage of being minimally invasive and hence, relatively atraumatic, this technique has made significant foray into management of biliary obstruction (both benign and malignant) and post-surgical biliary complications. This review focuses on the key technical aspects of the procedure along with the commonly anticipated complications that have a significant bearing on the outcome. The authors, thereby, attempt to add their own experience to the existing literature about the various tricky situations that may be encountered during the course of the procedure and tips to circumvent them.

Objectives The objective of this study was to present the procedural details and digital subtraction angiography (DSA) findings of perioperative chest-wall collateral embolization (PCCE) and compare intraoperative blood loss in patients of pulmonary aspergilloma (PA) undergoing lung resection with and without PCCE. Materials and Methods Since November 2017, we have performed PCCE in 17 patients (14 males, three females, age 34.41 ± 12.85 years) before surgery for PA (embolization group). Retrospective evaluation of these patients was done, DSA findings were noted, and perioperative parameters (surgical approach, extent of resection, operative time, blood loss, blood transfusion, morbidity grade, and length of post-operative stay) were compared with a comparative cohort of 24 patients of PA (21 males, three females, mean age 36.13 ± 12.58 years) who underwent thoracic surgery without PCCE (May 2013–November 2017) (control group) using the Mann–Whitney U test. Results A total of 55 arteries were embolized in 17 patients (mean 3.23 arteries per patient). Technical success could be achieved in all patients without any procedure-related complications. The most common arteries embolized were posterior intercostal arteries (29) followed by costocervical trunk (10), superior thoracic (8), lateral thoracic (5), and internal thoracic arteries (3). The mean blood loss was significantly lower in the embolization group compared with the control group (676.47 vs. 1,264.58 mL, p = 0.015). Within the embolization group, patients who underwent video-assisted thoracoscopic surgery had even lower blood loss compared with open surgery cases (466 vs. 887.50 mL, p-value = 0.046). Conclusion PCCE is a simple and safe procedure, useful in reducing intra-operative blood loss in patients undergoing surgery for peripherally located PA.

There is a lot of ambiguity in the usage of correct terminology in the description of vascular malformations and tumors. Hemangioma and arteriovenous malformation (AVM) are the most commonly used terms and are the mostly incorrectly used as well! The aim of this review article was to lay out the correct nomenclature and describe the correct usage for the physicians and radiologists involved in diagnosing and managing these lesions. We describe the various classification systems which have been devised to define the multiple entities included under vascular anomalies. The latest classification system that should be adhered to is per the International Society for the Study of Vascular Anomalies, approved at the 20th ISSVA Workshop held in Melbourne in April 2014, last revised in May 2018. The main features of the latest revision have been highlighted. This classification, however, does not list the diagnostic clinico-radiological features for each entity. In addition, guidelines regarding the appropriate use of available imaging modalities are lacking in the literature. We, hereby, aim to address these pertinent issues in this review article.