Dengue virus, a RNA virus of family Flaviviradae is considered non-neurotropic. Increasing studies and case reports reveal neurological manifestations of dengue virus. In our case series, we have evaluated magnetic resonance imaging (MRI) findings of 3 patients with dengue fever diagnosed by positive dengue NS1 antigen with neurological symptoms, which revealed nonspecific imaging features of dengue encephalitis in two cases and dengue meningoencephalitis in one case. Autopsy findings are also correlated in 2 patients who succumbed to their disease. This case series underlines the consideration of dengue encephalitis in patients of dengue fever with neurological symptoms and relevant imaging findings.

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The bony pelvis is constituted by the ilium, ischium, pubis, and sacrum. The pelvic radiograph is an important component of the skeletal survey performed in suspected skeletal dysplasia. Most of the common skeletal dysplasias have either minor or major radiological abnormalities; hence, knowledge of the normal radiological appearance of bony pelvis is vital for recognizing the early signs of various skeletal dysplasias. This article discusses many common and some uncommon radiological findings on pelvic radiographs along with the specific dysplasia in which they are seen; common differential diagnostic considerations are also discussed.

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Despite being decked as the most prized compounds in the nugget box of contrast agents for clinical radiologists, and carrying an indisputable tag of safety of the US Food and Drug Administration for close to three decades, all may not be seemingly well with the family of gadolinium compounds. If the first signs of violations of primum non nocere in relation to gadolinium-based contrast agents (GBCAs) appeared in the millennium year with the first published report of skin fibrosis in patients with compromised renal function, the causal relationship between the development of nephrogenic systemic fibrosis (NSF) and GBCAs, first proposed by two European groups in 2006, further precluded their use in renocompromised patients. The toxicity, pharmacokinetics, and pharmacodynamics of GBCAs, however, has come under hawk-eyed scrutiny with recent reports that gadolinium tends to deposit cumulatively in the brain of patients with normal hepatobiliary function and intact blood–brain barrier. While the jury on the long-term hazard significance of this critical scientific finding is still out, the use of GBCAs must be guided by due clinical diligence, avoidance of repeated doses, and preferring GBCAs with the best safety profiles.

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Background: Perianal fistula is a commonly encountered condition in routine surgical practice. Accurate presurgical mapping of these tracts is vital to prevent recurrence. We have assessed the effectiveness of percutaneous instillation of aqueous jelly prior to magnetic resonance (MR) fistulography. Aims and Objectives: To study the role of percutaneous instillation of aqueous jelly in fistulous tracts prior to MR fistulography. Materials and Methods: All patients with active discharge, referred for MR fistulography between January 2014 and April 2016, were included in this study. Approximately 3–5 ml of sterile aqueous jelly was percutaneously instilled into the external openings prior to MR fistulography. Post MR fistulography, patients were monitored till surgery for pain, fever, or bleeding.The type of fistulae, location of internal openings, lateral ramifications, and presence of abscess were compared with per operative findings for diagnostic accuracy. Results: Sixty-four patients enrolled in our study had undergone preoperative MR fistulography with aqueous jelly instillation. MR fistulography revealed a total of 77 tracts and showed a sensitivity and specificity of 100% in delineation of type of tract. Forty-nine internal openings were identified with 94.2% sensitivity, 100% specificity, and 95.3% accuracy. 90.5% sensitivity, 100% specificity, and accuracy of 97% were observed in delineation of lateral ramifications. None of the patients reported pain, fever, or bleeding post procedure till surgery. Conclusion: Percutaneous instillation of aqueous jelly prior to MR fistulography is a safe, cost effective, and accurate technique to provide a comprehensive delineation of the complex anatomy of perianal fistulae.

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Horseshoe kidney is the most common congenital renal fusion anomaly with an incidence of 1 in 400–600 individuals. The most common type is fusion at the lower poles seen in greater than 90% of the cases, with the rest depicting fusion at the upper poles, resulting in an inverted horseshoe kidney. Embryologically, there are two theories hypothesizing the genesis of horseshoe kidney – mechanical fusion theory and teratogenic event theory. As an entity, horseshoe kidney is an association of two anatomic anomalies, namely, ectopia and malrotation. It is also associated with other anomalies including vascular, calyceal, and ureteral anomalies. Horseshoe kidney is prone to a number of complications due to its abnormal position as well as due to associated vascular and ureteral anomalies. Complications associated with horseshoe kidney include pelviureteric junction obstruction, renal stones, infection, tumors, and trauma. It can also be associated with abnormalities of cardiovascular, central nervous, musculoskeletal and genitourinary systems, as well as chromosomal abnormalities. Conventional imaging modalities (plain films, intravenous urogram) as well as advanced cross-sectional imaging modalities (ultrasound, computed tomography, and magnetic resonance imaging) play an important role in the evaluation of horseshoe kidney. This article briefly describes the embryology and anatomy of the horseshoe kidney, enumerates appropriate imaging modalities used for its evaluation, and reviews cross-sectional imaging features of associated complications.

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Aims: To assess the severity of acute pancreatitis (AP) using computed tomography (CT) severity index (CTSI) and modified CT severity index (MCTSI), to correlate with clinical outcome measures, and to assess concordance with severity grading, as per the revised Atlanta classification (RAC). Materials and Methods: In this prospective study approved by the Institutional Review Board (November 2014 to March 2016), sixty patients with AP (as per the RAC definition) underwent contrast-enhanced computed tomography (CECT) 5–11 days (median 6 days) after symptom onset. Two radiologists, blinded to clinical parameters, independently assessed CTSI and MCTSI (differences were resolved by consensus). Clinical outcome parameters included duration of stay in the hospital and intensive care unit (ICU), presence of persistent organ failure (OF), evidence of infection, need for intervention, and mortality. Results: We included 60 cases [36 males, age range 19–65 (mean 37) years]. As per the RAC, 26 patients had mild AP, 12 moderately severe, and 22 severe AP. According to CTSI and MCTSI, mild, moderate, and severe cases were 27 (45%), 19 (31.7%), 14 (23.3%) and 24 (40%), 10 (16.7%), 26 (43.3%), respectively. MCTSI was concordant with the RAC grading in 54 (90.0%), CTSI was concordant in 47 (78.3%), and both were concordant in 43 (71.7%) cases. Area under the receiver-operating characteristic (ROC) curves (AUROC) was compared by the Hanley and McNeil method. Both CTSI and MCTSI were significantly associated with outcome parameters (P < 0.001), except duration of ICU stay. Sensitivity, specificity, positive predictive value (PPV), and accuracy of CTSI for detecting moderate/severe disease were 97.1%, 100%, 100%, and 98.3% respectively, and of MCTSI were 100%, 92.3%, 94.4%, and 96.7% respectively. Conclusion: Both CTSI and MCTSI showed significant correlation with clinical outcome parameters, and good concordance with RAC grading of severity. MCTSI showed a higher sensitivity but lower specificity than CTSI in differentiating mild from moderate/severe AP.

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Vascular structures in the abdomen can compress or be compressed by adjacent structures. Classic imaging findings of vascular compressions, including median arcuate ligament syndrome, superior mesenteric artery syndrome, nutcracker syndrome, portal biliopathy, May-Thurner syndrome, and ureteropelvic junction obstruction will be discussed here. It is important to correlate imaging findings and clinical data to identify asymptomatic vascular compression which requires no treatment, intermittent vascular compression with nonspecific or vague clinical manifestation, and the subset of patients with true syndromes who will benefit from treatment.

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Although a common occurrence, cystic lesions of the pancreatico-biliary tree (PBT) may pose a diagnostic dilemma because they encompass a large number of neoplastic and benign processes with varied clinical symptoms. Knowledge of lesion classification and characterization are essential in making an accurate prospective diagnosis. This is necessary for identifying clinically significant cystic masses, which at times may require invasive intervention from indolent, nonneoplastic lesions, for which surveillance may suffice. Today, there is an arsenal of modalities for assessing the PBT, however, magnetic resonance imaging (MRI) remains at the forefront for characterizing cystic morphology and fluid content, internal septations, solid component, enhancement patterns, as well as assessing the surrounding normal structures. This pictorial review aims to review the spectrum of MRI features, which will aid in the differential diagnoses of cystic lesions of the PBT and mimickers, enabling the radiologist to reach a more confident diagnosis.

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Rhabdomyosarcoma (RMS) is a malignant mesenchymal tumor arising from the embryonal muscle cells (rhabdomyoblasts), and is the most common soft tissue sarcoma in children and young adults accounting for 4–6% of all malignancies in this age group. Though rare overall, embryonal rhabdomyosarcoma is the most common malignancy arising in the pediatric female genitourinary tract with sarcoma botryoides being the most common variant of the tumor. In young and adolescent individuals, the cervix and uterus are affected; whereas in infants, vaginal lesions are more common. Imaging plays a crucial role not only in the initial diagnosis but also in long-term follow-up of genital RMS. We describe a rare case of embryonal rhabdomyosarcoma of the vagina occurring in a 23-year-old female who presented with abnormal vaginal bleeding ever since she was a child.

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Metronidazole-induced neuro-toxicity, though rare, is known. A characteristic spatial distribution of lesions in cerebellar dentate nuclei and dorsal pons is known. However, temporal progression of lesions on magnetic resonance imaging (MRI) has not been described previously. We describe two such cases which presented initially with splenial hyperintesity and showed progression to characterstic lesions. Both cases improved with stoppage of metronidazole.

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Purpose: To determine whether or not there were any differences in the measurement techniques used by orthopedic and radiology specialists in the evaluation of magnetic resonance (MR) images for the diagnosis of patella alta in adolescents. Materials and Methods: Evaluations were performed by three orthopedic specialists (Group I) and three radiology specialists (Group II) regarding the presence of patella alta in 40 adolescents cases using the Insall–Salvati, Caton–Deschamps, Blackburne–Peel, and modified Insall–Salvati indices on MR images obtained to diagnose patellar instability. Results: The Fleiss Kappa conformity levels for Insall–Salvati, Caton–Deschamps, Blackburne–Peel, and modified Insall–Salvati measurements were 0.531, 0.559, 0.246, and 0.272, respectively, in Group I, and 0.699, 0.346, 0.516, and 0.394, respectively, in Group II. Conclusion: The radiology specialists were found to have greater conformity in the evaluation of all patella alta indices, which was probably due to their greater familiarity with radiological measurements than that of the orthopedic specialists.

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Purpose: To evaluate the technical and clinical success of radiofrequency ablation of osteoid osteoma and analyze the factors responsible for clinical success. We also tried to investigate the role of follow-up computed tomography (CT) imaging. Materials and Methods: This is a prospective study approved by the institute's ethics committee involving 87 patients with appendicular osteoid osteoma. CT-guided radio frequency ablation was performed using a bipolar ablation system. Patients were followed up over 15.4 (4–24) months for pain, and clinical success/failure was determined using established criteria. Patients with clinical failure were taken for repeat ablation. Follow-up CT was obtained at 6 months and correlated with clinical success. Procedural scans were later reviewed for technical success in a blinded manner and correlated with clinical success along with other imaging and patient characteristics. Results: Mean pre-procedure visual analog scale (VAS) score was 7.0 ± 0.8. Primary success rate after single session was 86.2%(75/87 patients), and overall success rate after one/two sessions was 96.6%(84/87). No major complications were noted. Technical success rate was 89.7%(78/87). All 9 patients who had a suboptimal needle positioning had recurrence where as three patients had recurrence despite technical success. None of the imaging characteristics or history of prior intervention was significantly associated with clinical success. Follow-up CT showed advanced bone healing in 48 lesions, and was confined to the treatment success group. Alternately, minimal/absent bone healing was seen in all (12) patients of primary treatment failure and 27 patients with treatment success. Conclusions: CT-guided percutaneous radio frequency ablation is a safe and highly effective treatment for osteoid osteomas even in recurrent and residual cases. Technical success is the most important parameter affecting the outcome. Post radio frequency ablation CT findings have a good positive but a poor negative predictive value in prognostication.

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Purpose: Periventricular white matter is most commonly injured in preterm babies with hypoxia. To assess white matter damage, we decided to perform diffusion tensor imaging (DTI) in preterm children with history of hypoxia and magnetic resonance imaging (MRI) features of periventricular leukomalacia (PVL) (PTH). We hypothesized that the PTH have reduced number of white matter fibres compared to age matched pre term children without hypoxia (PTHO), and also depending on the severity of PVL, there could be reduction in the number of fibres as well. Materials and Methods: The present study was carried out at the Government Medical College, Thiruvananthapuram. DTI was performed on 15 PTH and 15 PTHO. We measured number of fibres and fractional anisotropy of corpus callosum (CC) and optic radiations (OR). Results: There was significant difference between two groups with regard OR (P < 0.001).The mean number of OR fibres in cases and control was 104 ± 28.44 (mean ± SD) and 578 ± 286 (mean ± SD), respectively.The mean number of CC in cases was 953 ± 429 and in controls was 1625 ± 116 with a P value <0.56. No significant difference in FA was seen between cases and controls (P = 0.94). Conclusions: Preterm children with history of hypoxia and MRI features of PVL show reduced number of CC and OR compared to preterm children without hypoxia. There was significant correlation between PVL severity and number of OR fibres which could be due to the preferential involvement of periventricular white matter, in which OR has a major contribution.

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Aspergillomas are fungal balls developing in pre-existing lung cavities, which are most commonly secondary to tuberculosis. Aspergillomas can cause hemoptysis due to erosion of the blood vessels in cavity walls, which can often be recurrent, massive, and life-threatening. Bronchial artery embolization is considered to be the treatment of choice for short-term control of hemoptysis, and lobectomy as the definitive treatment for aspergilloma. We present a unique observation in two cases of aspergilloma where the fungal balls disappeared radiologically after bronchial artery embolization performed for massive hemoptysis.

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Objective: To evaluate the role of exponential apparent diffusion coefficient (ADC) as a tool for differentiating benign and malignant breast lesions. Patients and Methods: This prospective observational study included 88 breast lesions in 77 patients (between 18 and 85 years of age) who underwent 3T breast magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) using b-values of 0 and 800 s/mm² before biopsy. Mean exponential ADC and ADC of benign and malignant lesions obtained from DWI were compared. Receiver operating characteristics (ROC) curve analysis was undertaken to identify any cut-off for exponential ADC and ADC to predict malignancy. P value of <0.05 was considered statistically significant. Histopathology was taken as the gold standard. Results: According to histopathology, 65 lesions were malignant and 23 were benign. The mean ADC and exponential ADC values of malignant lesions were 0.9526 ± 0.203 × 10⁻³ mm²/s and 0.4774 ± 0.071, respectively, and for benign lesions were 1.48 ± 0.4903 × 10⁻³ mm²/s and 0.317 ± 0.1152, respectively. For both the parameters, differences were highly significant (P < 0.001). Cut-off value of ≤0.0011 mm²/s (P < 0.0001) for ADC provided 92.3% sensitivity and 73.9% specificity, whereas with an exponential ADC cut-off value of >0.4 (P < 0.0001) for malignant lesions, 93.9% sensitivity and 82.6% specificity was obtained. The performance of ADC and exponential ADC in distinguishing benign and malignant breast lesions based on respective cut-offs was comparable (P = 0.109). Conclusion: Exponential ADC can be used as a quantitative adjunct tool for characterizing breast lesions with comparable sensitivity and specificity as that of ADC.

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Big data is extremely large amount of data which is available in the radiology department. Big data is identified by four Vs – Volume, Velocity, Variety, and Veracity. By applying different algorithmic tools and converting raw data to transformed data in such large datasets, there is a possibility of understanding and using radiology data for gaining new knowledge and insights. Big data analytics consists of 6Cs – Connection, Cloud, Cyber, Content, Community, and Customization. The global technological prowess and per-capita capacity to save digital information has roughly doubled every 40 months since the 1980's. By using big data, the planning and implementation of radiological procedures in radiology departments can be given a great boost. Potential applications of big data in the future are scheduling of scans, creating patient-specific personalized scanning protocols, radiologist decision support, emergency reporting, virtual quality assurance for the radiologist, etc. Targeted use of big data applications can be done for images by supporting the analytic process. Screening software tools designed on big data can be used to highlight a region of interest, such as subtle changes in parenchymal density, solitary pulmonary nodule, or focal hepatic lesions, by plotting its multidimensional anatomy. Following this, we can run more complex applications such as three-dimensional multi planar reconstructions (MPR), volumetric rendering (VR), and curved planar reconstruction, which consume higher system resources on targeted data subsets rather than querying the complete cross-sectional imaging dataset. This pre-emptive selection of dataset can substantially reduce the system requirements such as system memory, server load and provide prompt results. However, a word of caution, “big data should not become “dump data” due to inadequate and poor analysis and non-structured improperly stored data. In the near future, big data can ring in the era of personalized and individualized healthcare.

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Aims: The study was carried out to evaluate the early outcomes using Radiofrequency Ablation (RFA) for unresectable liver metastases in the management of metastatic colorectal cancer (mCRC) from an area of low endemicity. Material and Methods: 60 Patients with unresectable colorectal liver metastases had undergone 88 sessions of RFA from January 2007 till December 2013. The results were retrospectively analysed to evaluate the outcomes in terms of efficacy and survival rates. Results: The median follow up of patients in our series was 24.8months. 35/52 (67.3%) patients had complete response at 3 months while 8 patients were lost to follow up. Of the 17 patients who had recurrence, 4 (23.5%) were at the ablated site while 13 patients (76.4%) progressed elsewhere. Abdominal pain was commonest post procedural symptom (20%). There was no procedure related mortality or any major complications. Mean disease free interval and Progression free survival was 6.7 and 13.1 months. Estimated median survival in patients with liver limited disease and those with small lesion (<3cm) was 3.79 years and 3.45 years respectively. Median survival in patients with lesion size 3–5 cms was 1.5 years. Annual survival rates would be 94.5%, 55.2% and 26.2% for 1, 3 and 5 years. Conclusion: Radiofrequency ablation of unresectable liver metastases is effective in treatment of mCRC. Estimated survival rates and Annual survival rates at our institute from the low endemic region also follow the global trend. Size of the lesion was an important predictor of efficacy of RFA. Presence of extrahepatic disease and lesion size >3 cm was associated with decreased survival.

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Extramedullary lymphoma infiltration of the breast by lymphoblastic lymphoma is very rare and most cases are of B-cell lineage; T-cell neoplasms represent less than 10% of all breast lymphomas. Here, we report one patient with lymphoblastic lymphoma and one patient with leukemia, who have similar lesions in breasts with different ultrasound elastography findings. Ultrasound-guided tru-cut biopsies were performed and the first lesion was confirmed as lymphoma infiltration and the second as fibroadenoma. In cases of breast mass presence in patients with a history of hematologic malignancies such as lymphoma or leukemia, breast infiltration should be kept in mind. Elastography findings can assist in the differentiation of these lesions and further investigations or biopsies can be avoided.

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Right isomerism, also known as Ivemark syndrome, is an unusual degree of symmetry of some of the abdominothoracic viscera reflecting bilateral right-sidedness. We report an exceedingly rare occurrence of anomalous drainage of the left hepatic vein to the left-sided atrium in a patient of right isomerism. With this case report, we further endorse that the isomerism of atrium might extend beyond the appendages, a view that has been long dismissed by the existing literature.

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Immunoglobulin G4 (IgG4)-related systemic disease (IgG4-RSD) is a new systemic entity associated with autoimmune pancreatitis (AIP). Other organ involvements take the form of sclerosing cholangitis, sclerosing cholecystitis, sclerosing sialadenitis, retroperitoneal fibrosis, and interstitial nephritis. Recently, lung diseases related to IgG4 have been described to occur with or without other organ involvement. These diseases include interstitial lung disease (ILD), pulmonary inflammatory pseudotumor, and lymphomatoid granulomatosis. Most of these cases occur in combination with AIP, which also appears to have a general preponderance for males. The true incidence of IgG4-related ILD and the incidence of AIP are unknown. Here, we describe a case of a 53-year-old gentleman who presented with weight loss, fever, loose motions, altered sensorium, and persistent low hemoglobin, for which he was referred for 18-fluorodeoxyglucose positron emission tomography/computed tomography scan to diagnose probable underlying occult malignancy/paraneoplastic syndrome. It revealed features suggestive of IgG4 disease involving the pancreas and lungs, which was confirmed subsequently.

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