CT FFR A paradigm shift in evaluation of coronary artery disease Anirudh Kohli Indian Journal of Radiology and Imaging 2019 29(3):233-235

Imaging protocols for CT chest: A recommendation Ashu Seith Bhalla, Abanti Das, Priyanka Naranje, Aparna Irodi, Vimal Raj, Ankur Goyal Indian Journal of Radiology and Imaging 2019 29(3):236-246 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.

Radiation dose reference card for interventional radiology procedures: Experience in a tertiary referral centre Anna Varghese, Shyamkumar N Keshava, Vinu Moses, George Koshy, Suraj Mammen, Munawwar Ahmed, Roshan S Livingstone Indian Journal of Radiology and Imaging 2019 29(3):247-252 Background: Fluoroscopy-guided interventions can potentially increase radiation risk to patients, if awareness on angiographic imaging technique and radiation dose is neglected. Aim: To develop patient radiation dose reference card from standardized imaging techniques for various radiology interventions performed using flat detector based angiography system. Materials and Methods: Real-time monitoring of angiographic exposure parameters and radiation dose were performed for 16 types of radiological interventions. Effective dose (ED) was estimated from dose area product (DAP) using PCXMC Monte Carlo simulation software. Radiation risk levels were estimated based on Biological Effects of Ionising radiation (BEIR) report VII predictive models for an Asian population. Results: Pulse rates of 7.5 pps and 0.6 mm Copper filtration during fluoroscopy and 4 frames per second (fps) and 0.1-0.3 mm Cu filtration during image acquisitions were found to reduce radiation dose. Owing to increased number of image acquisitions, DAP was highest during diagnostic spinal angiography 186.7 Gycm2 (44.0–377.5). This resulted in highest ED of 59.4 mSv with moderate risk levels (1 in 1000 to 1 in 500). Most of the radiological interventions had low radiation risk levels (1 in 10,000 to 1 in 1000). Conclusion: The patient radiation dose reference card is valuable to the medical community and can aid in patient counselling on radiation induced risk from radiological interventions.

Computed tomography guided radio-frequency ablation of osteoid osteomas in atypical locations Julie Senne, Ryan Davis, Junaid Yasin, Olubusola Brimmo, Andrea Evenski, Ambarish P Bhat Indian Journal of Radiology and Imaging 2019 29(3):253-257 Purpose: Percutaneous radio-frequency ablation is a minimally invasive treatment option for osteoid osteomas. The ablation process is straightforward in the more common locations like the femur/tibia. Surgery has historically been the gold standard, but is currently used in lesions, that may not be effectively and safely ablated, i.e. close to skin/nerve. Radio-frequency ablation can still be used in such cases along with additional techniques/strategies to protect the sensitive structures and hence improve the outcomes. The authors describe their experience with four challenging osteoid osteoma ablation cases. Methods: We retrospectively reviewed radio-frequency ablations of four osteoid osteomas in rather atypical locations, the protective techniques/strategies employed, the adequacy and safety of the radio-frequency ablation with the use of these techniques. Results: All patients had complete resolution of pain with no recurrence in the follow-up period. No complications were reported. Conclusion: RFA has been proven to be an effective and safe option for treatment of OOs in the common locations. It is generally recommended to have a 1 cm safety margin between the RF probe and any critical structures in the vicinity. However, with OOs in atypical locations this may not be always possible and hence additional techniques may be needed to ensure protection of the surrounding sensitive structures and also allow for effective ablation.

Current review with evolving management strategies in critical limb ischemia Arun Sharma Indian Journal of Radiology and Imaging 2019 29(3):258-263 Critical limb ischemia represents the end stage of peripheral artery disease, which is associated with impaired quality of life and considerable morbidity and mortality. Economical impact of the disease is huge with a substantial burden on patients, healthcare providers, and resources. Varied therapeutic strategies have been employed in the management of these patients. These patients usually have complex multilevel occlusive arteriopathy with significant comorbidities, rendering surgical interventions undesirable in many cases. Recent therapeutic advances with evolving endovascular techniques and gene or cell-based therapies have the potential to dramatically change the therapeutic outlook in these patients.

MR neurography in Parsonage-Turner syndrome Vaishali Upadhyaya, Divya Narain Upadhyaya, Richa Bansal, Tarun Pandey, Ashok Kumar Pandey Indian Journal of Radiology and Imaging 2019 29(3):264-270 Background and Aims: Parsonage Turner Syndrome is a well known clinical entity. Several excellent articles have succinctly described Magnetic Resonance Imaging (MRI) findings in PTS. However, these articles have inferred neural involvement in PTS based on the patterns of denervation of muscles in the shoulder region. The aim of this study is to directly visualize the distribution and extent of abnormality in MR Neurography (MRN) of the brachial plexus in known cases of brachial plexus neuritis or Parsonage-Turner Syndrome (PTS). Methods: 15 patients who were diagnosed with PTS based on clinical and electrophysiological findings participated in the study. MRN of the brachial plexus was done in a 1.5T system using a combination of T1W (T1-weighted), T2W (T2-weighted) fat-saturated, STIR (Short Tau Inversion Recovery), 3D STIR SPACE (Sampling Perfection with Application Optimized Contrasts) and 3D T2W SPACE sequences. Findings were recorded and assessed. Results: The age range of our patients was 7-65 years (mean 37.87 years). Most of the patients had unilateral symptoms. All patients had weakness in shoulder abduction. Other common associated complaints included pain in the shoulder/neck/arm and preceding fever. MRN revealed the percentage of involvement of roots, trunks, cords and terminal branches was 53.3%, 46.7%, 40% and 13.3% respectively. Evidence of muscle denervation in the form of edema, fatty infiltration and atrophy was noted in 8 (53.3%) patients. Conclusion: Most of the patients in this study had unilateral involvement on MRN. The roots were the commonest site of involvement followed by the trunks, cords and terminal branches. C5 was the most commonly involved root.

Solid variant ABC of long tubular bones: A diagnostic conundrum for the radiologist Adarsh Ghosh, Anuradha Singh, Richa Yadav, Shah A Khan, Venkatesan S Kumar, Shivanand Gamanagatti Indian Journal of Radiology and Imaging 2019 29(3):271-276 Solid variant of aneurysmal bone cyst (sABC) is an extremely rare, reactive and non-neoplastic osseous lesion. On imaging it presents as a diaphyseal aggressive, eccentrically placed lytic and expansile lesion. However, differentiating this entity from the other possible malignant differentials is confounded by the histopathology mimicking several commoner lesions. We describe the distinctive MRI features of sABC of long bones from a series of four cases and briefly review the literature. We hope this review will educate all radiologists about this rare entity increasing their diagnostic confidence while formulating differentials for similar appearing lesions.

Role of MRI in staging and surgical planning and its clinicopathological correlation in patients with renal cell carcinoma Hira Lal, Paritosh Singh, Manoj Jain, Uday Pratap Singh, Sanjoy Kumar Sureka, Rajanikant R Yadav, Raghunandan Prasad, Pragati Verma, Anuradha Singh, Priyank Yadav Indian Journal of Radiology and Imaging 2019 29(3):277-283 Background and Aims: Radiological evaluation of renal cell carcinoma (RCC) is used for non-invasive staging for better surgical planning. However, the correlation of radiological staging using magnetic resonance imaging (MRI) with histopathological findings has not been done so far. The aim of this study is to assess the role of MRI in pre-operative staging of RCC in patients undergoing radical nephrectomy and nephron sparing surgery (NSS) and correlate it with histopathological findings. Settings and Design: This prospective observational study was conducted from February 2015 to October 2016 at a tertiary care hospital in northern India. Methods: MR imaging was done on 3 Tesla MR scanner (Signa Hdxt General Electrics, Milwaukee, USA). Preoperative staging was based on 2010 TNM staging system. The preoperative parameters in MRI were tumor size, detection/breach of pseudocapsule, tumor extension into perirenal fat and detection of tumor venous thrombus. The staging on MRI was compared with surgical and pathological staging. Statistical Analysis Used: The agreement between these three staging methods was determined using the kappa statistics (0.0-0.2, poor; 0.2-0.4, fair; 0.4-0.6, moderate; 0.6-0.8, good; 0.8-1.0, excellent). Results: 30 patients with suspected RCC underwent NSS (n = 10) and radical nephrectomy (n = 20). Mean tumor size was 9.66 ± 2.99 cm in the radical nephrectomy group and 4.06 ± 1.16 cm in the NSS group. There was perfect agreement between MRI, surgical and pathological staging for breach of pseudocapsule (κ =1.0, Percentage of Agreement = 100%,P < 0.05). In none of the patients, MRI missed extension beyond the Gerota's fascia or presence of venous thrombus. Conclusion: MRI staging of RCC is an accurate predictor of the surgical and pathological stage and has the potential to become a useful tool for preoperative identification of patients with RCC who can undergo NSS.

MR-guided focused ultrasound surgery: A novel non-invasive technique in the treatment of adenomyosis –18 month's follow-up of 12 cases Bhawna Dev, Sameera Gadddam, Mitesh Kumar, Suresh Varadarajan Indian Journal of Radiology and Imaging 2019 29(3):284-288 Background: Adenomyosis is a gynecological condition of the uterus, characterized by the presence of ectopic endometrial tissue in the myometrium. Hysterectomy, uterine artery embolization, and endometrial ablation therapy are the various surgical treatment options available for adenomyosis. A novel and globally upcoming technique is MR-guided focused ultrasound surgery “MRgFUS,” which is a promising non-invasive surgical treatment option. This study was carried out to determine the effectiveness of MRgFUS in the symptomatic management of adenomyosis. Subjects and Methods: This study was carried out as a long-term follow-up study among 12 cases of adenomyosis, which were treated by MR-guided focused ultrasound. In all these participant's, three parameters – symptom severity score (SSS), menstrual pain score accessed using visual analogue score (VAS), and number of approximate pads used during menstruation were recorded prior to the treatment and on follow-up at 3, 9, and 18 months, respectively. The Friedman's test was used to test the difference in the values of scores before and after treatment. Results: There was a significant improvement in the SSS, VAS, and the numbers of sanitary napkins used after surgery and sustained during the long-term follow-up. These values were statistically significant (P < 0.05). Conclusion: MRgFUS can be used in successful treatment of adenomyosis/focal adenomyoma by careful selection of the participant, good planning, and proper monitoring of the technique during ablation.

Applications of dual energy CT in clinical practice: A pictorial essay Parang S Sanghavi, Bhavin G Jankharia Indian Journal of Radiology and Imaging 2019 29(3):289-298 In dual-energy CT (DECT), two different x-ray spectra are used to acquire two image datasets of the same region, to allow the analysis of energy-dependent changes in the attenuation of different materials. Each type of material demonstrates a relatively specific change in attenuation between images obtained with a high-energy spectrum and those obtained with a low-energy spectrum. Based on the relatively specific change in attenuation with two different energies, material composition information can be obtained to allow tissue characterization. The DECT ability of material differentiation allows bone removal in various CT angiography studies and bone marrow edema depiction, while with material optimization, metal artefacts can be significantly reduced to almost nil. DECT allows material separation to differentiate uric acid crystals from calcium to determine the composition of urinary calculi and to diagnose gout. Using the DECT ability of material decomposition, iodine maps can be generated, which are useful in the evaluation of any enhancing lesion in the body without the need to obtain a plain scan and allow perfusion maps to be created in cases of pulmonary thromboembolism.