¹⁸Fluorine-2-fluoro-2-Deoxy-d-glucose (¹⁸ F-FDG) positron emission tomography/computerized tomography (PET/CT) is a well-established functional imaging method widely used in oncology. In this article, we have incorporated the various indications for¹⁸ FDG PET/CT in oncology based on available evidence and current guidelines. Growing body of evidence for use of¹⁸ FDG PET/CT in select tumors is also discussed. This article attempts to give the reader an overview of the appropriateness of using¹⁸ F-FDG PET/CT in various malignancies.

Current standard of care for treatment of newly diagnosed high grade gliomas is surgery followed by concomitant radiotherapy (RT) and chemotherapy (CT) with temozolomide (TMZ). Recently, bevacizumab, an anti - angiogenic agent has also been approved for treatment of recurrent gliomas. Baseline imaging after excision is optimally obtained in the first 24 hours. When baseline postoperative imaging is delayed beyond 24 hours, subacute hemorrhage, subacute ischemia and inflammation at the resection margins render differentiation from residual tumor challenging. Radiation necrosis is a well recognized entity and is differentiated from recurrence based on morphology on structural imaging, presence of lipid - lactate complexes with lack of choline on spectroscopy and low normalized cerebral blood volume (CBV) ratios at perfusion imaging. Novel chemotherapies have lead to the occurrence of interesting but sometimes confusing post treatment imaging appearances including the phenomena of 'pseudoprogression' and 'pseudoresponse'. Pseudoprogression refers to transient, self resolving focal enhancement mediated by TMZ-induced increased vascular permeability and local inflammatory response. Pathologically, these lesions do not have viable tumor. The lesions stabilize or regress without further treatment and are usually clinically asymptomatic. Pseudoresponse refers to rapid regression of enhancement, perfusion, mass effect and midline shift caused by the anti - angiogenic effect of bevacizumab. It is termed pseudoresponse since biological tumor persists as non-enhancing altered signal. It is important for radiologists to be aware of these entities seen on post treatment imaging of gliomas, as misinterpretation may lead to inappropriate management decisions and prognostication.

Lung cancer is one of the leading causes of cancer-related deaths. Accurate assessment of disease extent is important in deciding the optimal treatment approach. To play an important role in the multidisciplinary management of lung cancer patients, it is necessary that the radiologist understands the principles of staging and the implications of radiological findings on the various staging descriptors and eventual treatment decisions.

Morphologic methods such as the Response Evaluation Criteria in Solid Tumors (RECIST) are considered as the gold standard for response assessment in the management of cancer. However, with the increasing clinical use of antineoplastic cytostatic agents and locoregional interventional therapies in hepatocellular carcinoma (HCC), conventional morphologic methods are confronting limitations in response assessment. Thus, there is an increasing interest in new imaging methods for response assessment, which can evaluate tumor biology such as vascular physiology, fibrosis, necrosis, and metabolism. In this review, we discuss various novel imaging methods for response assessment and compare them with the conventional ones in HCC.

Neuroblastoma is the third common tumor in children. Imaging plays an important role in the diagnosis, staging, treatment planning, response evaluation and in follow-up of a case of Neuroblastoma. The International Neuroblastoma Risk Group task force has recently introduced an imaging-based staging system and laid down guidelines for uniform reporting of imaging studies. This review is an update on imaging in neuroblastoma, with emphasis on these guidelines.

Endometrial carcinoma (EC) is the most common gynecologic malignancy in the United States. Prognosis depends on patient age, histological grade, depth of myometrial invasion and/or cervical invasion, and the presence of lymph node metastases. Although EC is staged surgically according to the International Federation of Gynecology and Obstetrics (FIGO) system, preoperative imaging can assist in optimal treatment planning. Several imaging techniques such as transvaginal ultrasonography (TVUS), computed tomography (CT), and magnetic resonance imaging (MRI) have been used as diagnostic tools for preoperative staging of EC. Recently, positron emission tomography (PET), PET/CT, and PET/MRI have also been used in staging these patients. In this article, we review the value of imaging in diagnosis, staging, treatment planning, and detection of recurrent disease in patients with EC.

Imaging in rectal cancer has a vital role in staging disease, and in selecting and optimizing treatment planning. High-resolution MRI (HR-MRI) is the recommended method of first choice for local staging of rectal cancer for both primary staging and for restaging after preoperative chemoradiation (CT-RT). HR-MRI helps decide between upfront surgery and preoperative CT-RT. It provides high accuracy for prediction of circumferential resection margin at surgery, T category, and nodal status in that order. MRI also helps assess resectability after preoperative CT-RT and decide between sphincter saving or more radical surgery. Accurate technique is crucial for obtaining high-resolution images in the appropriate planes for correct staging. The phased array external coil has replaced the endorectal coil that is no longer recommended. Non-fat suppressed 2D T2-weighted (T2W) sequences in orthogonal planes to the tumor are sufficient for primary staging. Contrast-enhanced MRI is considered inappropriate for both primary staging and restaging. Diffusion-weighted sequence may be of value in restaging. Multidetector CT cannot replace MRI in local staging, but has an important role for evaluating distant metastases. Positron emission tomography-computed tomography (PET/CT) has a limited role in the initial staging of rectal cancer and is reserved for cases with resectable metastatic disease before contemplating surgery. This article briefly reviews the comprehensive role of imaging in rectal cancer, describes the role of MRI in local staging in detail, discusses the optimal MRI technique, and provides a synoptic report for both primary staging and restaging after CT-RT in routine practice.

Aims: Differentiating intracranial mass lesions on CT scan is challenging. The purpose of our study was to determine the perfusion parameters in various intracranial space-occupying lesions (ICSOL), differentiate benign and malignant lesions, and differentiate between grades of gliomas. Materials and Methods: We performed CT perfusion (CTP) in 64 patients, with age ranging from 17 to 68 years, having space-occupying lesions in brain and calculated relative cerebral blood flow (rCBF) and relative cerebral blood volume (rCBV). Results: We found significantly lower perfusion in low-grade gliomas as compared to high-grade tumors, lymphoma, and metastases. Similarly in infective lesions, TWT and abscesses showed significantly lower perfusion compared to TOT. In ring enhancing lesions, capsule of TWT showed significantly lower perfusion as compared to abscesses, TOT, and metastases. Conclusion: Thus, in conclusion, infective lesions can be differentiated from tumors like lymphomas, high-grade gliomas, or metastases based on perfusion parameters. The cut off value of rCBV 1.64 can be used to differentiate between low grade and high grade gliomas. However, depending only on perfusion parameters, differentiation between the tumors like lymphomas, high-grade gliomas, and metastases may not be possible.

Purpose: To study the location, origin, size and relationship of the vertebral artery and the transverse foramina in the lower cervical spine by computed tomographic angiography (CTA) measurements in the Indian population. Materials and Methods: A retrospective review of multi-detector CT (MDCT) cerebral angiography scans was done between June 2011 and February 2014. A total of 120 patients were evaluated. The diameter of the vertebral artery (AL) and the shortest distance between the vertebral artery and the medial (M), lateral (L), anterior (A), and posterior (P) borders of transverse foramen were studied. In addition, the shortest distance between the vertebral artery and pedicle (h) was also analyzed. Statistical Analysis: The means and their standard deviations (SD) were calculated in both the sexes. The t-tests were performed to look for significant sexual difference. Results: The largest vertebral artery diameter (AL) was at level C7 on the right side (3.5 ± 0.8) and at the level of C5 on the left side (3.7 ± 0.4). Statistically significant difference between males and females were seen at levels C4, C5, and C7. The diameter of the vertebral artery was smaller in females than males. The L value was greater than other parameters (M, A, P) at the same level in all the measurements. The h value was greatest at C6 level and shortest at C5. Conclusion: CTA is necessary before pedicle screw fixation due to variation in measurements at all levels. The highest potential risk of vertebral artery injury during cervical pedicle screw implantation may be at C5, then at C4, and the safest is at C7.

CNS Tuberculosis can manifest as meningitis, arachnoiditis and a tuberculoma. The rupture of a tubercle into the subarachnoid space leads to Tuberculosis Meningitis (TBME); the resulting hypersensitivity reaction can lead to an elevation of the intracranial pressure and hydrocephalus. While bedside optic nerve sheath diameter (ONSD) ultrasonography (USG) can be a sensitive screening test for elevated intracranial pressure in adult head injury, little is known regarding ONSD measurements in Tuberculosis Meningitis. Objectives: The aim of this study was to determine whether patients with TBME had dilation of the optic nerve sheath, as detected by ocular USG performed in the emergency department (ED). Materials and Methods: We conducted a prospective, observational study on adult ED patients with suspected TBME. Patients underwent USG measurements of the optic nerve followed by MRI. The ONSD was measured 3 mm behind the globe in each eye. MRI evidence of basilar meningeal enhancement and any degree of hydrocephalus was suggestive of TBME. Those patients without evidence of hydrocephalus subsequently underwent a lumbar puncture to confirm the diagnosis. Exclusion criteria were age less than 18 and obvious ocular pathology. In total, the optic nerve sheath diameters of 25 adults with confirmed TBME were measured. These measurements were compared with 120 control patients. Results: The upper limit of normal ONSD was 4.37 mm in control group. Those patients with TBME had a mean ONSD of 5.81 mm (SD 0.42). These results confirm that patients with tuberculosis meningitis have an ONSD in excess of the control data (P < 0.001). Conclusion: The evaluation of the ONSD is a simple non-invasive and potentially useful tool in the assessment of adults suspected of having TBME.

Osmotic myelinolysis is an acute, rare, demyelinating process. After the initial description of the condition by Adam and colleagues in 1959, many case series have been published describing the central and extrapontine myelinolysis. Imaging has a definitive role in establishing the diagnosis of osmotic myelinolysis in vivo and diffusion-weighted imaging reveals earliest changes in affected brain parenchyma. We report two cases of patients with proven malignancy who developed extrapontine myelinolysis after treatment for hyponatremia and progressed to central pontine myelinolysis within a week. This was confirmed with magnetic resonance (MR) imaging and clinical assessment. This temporal progression of MR features, especially on diffusion-weighted imaging, from extrapontine to central pontine myelinolysis in osmotic injury has not been described in literature to the best of our knowledge. An early MRI of the brain in suspected/high-risk cases of osmotic myelinolysis may show features of extrapontine myelinolysis in the form of restricted diffusion in bilateral basal ganglia and may serve as a guide for predicting progression, prognosticating and deciding further treatment of pontine myelinolysis. We propose that in a significant number of cases, central pontine myelinolysis may be predicted by doing an early MRI of the brain with diffusion-weighted imaging, when extrapontine symptoms start to develop. This can potentially increase the window period and possibilities for therapeutic intervention and may even help in prevention.

Although hilar cholangiocarcinoma is relatively rare, it can be diagnosed on imaging by identifying its typical pattern. In most cases, the tumor appears to be centered on the right or left hepatic duct with involvement of the ipsilateral portal vein, atrophy of hepatic lobe on that side, and invasion of adjacent liver parenchyma. Multi-detector computed tomography (MDCT) and magnetic resonance cholangiopancreatography (MRCP) are commonly used imaging modalities to assess the longitudinal and horizontal spread of tumor.

A surgical swab retained in the body after surgery is known as 'Gossypiboma'. The purpose of this report is to highlight an intramural vesical gossypiboma mimicking an invasive adnexal malignancy. A 28-year-old multiparous, with open-tubal ligation three years ago, presented with painless hematuria and a nontender mass on vaginal examination. USG suggested 'pelvic endometriosis' infiltrating into the bladder and cystoscopy showed no intraluminal extension of the mass. Contrast-enhanced computed tomography (CECT) and magnetic resonance imaging (MRI) misdiagnosed it as invasive malignancy of the fallopian tube. Exploratory laparotomy found it to be an intramural vesical gossypiboma. A pelvic gossypiboma infiltrating into the wall of the urinary bladder may easily be misinterpreted as an invasive pelvic malignancy on imaging and may make one consider unwarranted radical surgery.

We report an interesting sign in the sonological evaluation of neonatal cholestasis, which is hepatic subcapsular flow. Hepatic subcapsular flow is an early and useful marker in diagnosing biliary atresia.

Paragangliomas are the neuroendocrine tumors which arise from the chromaffin cell. Tumors arising from the adrenal medulla are known as pheochromocytomas, while others originating from the extra-adrenal site are known as extra-adrenal paragangliomas. Paraganglioma can be multifocal which can arise synchronously or metachronously. Paragangliomas are less functionally active than the pheochromocytomas; they secrete noradrenaline and rarely dopamine, while adrenal pheochromocytomas secrete adrenaline or nor-adrenaline. Nonfunctional multifocal paragangliomas are very rare. We report a case of a 45-year-old female with multifocal nonfunctional paragangliomas of the retroperitoneum and urinarybladder which were surgically removed, and the diagnosis was confirmed on histopathology.

The median arcuate ligament syndrome (MALS) or celiac artery compression syndrome (CACS) is a rare entity, presenting clinically with postprandial abdominal pain and weight loss. The diagnosis is made on computed tomography (CT) angiography, which reveals extrinsic compression of the proximal part of the celiac artery by the median arcuate ligament, producing a characteristic hooked appearance. We report a case of the celiac artery compression syndrome, diagnosed by Doppler USG evaluation.