Assessment of CT perfusion indices of the clinicoradiological response to anti-tubercular therapy in patients with intestinal tuberculosis.

AIM: To explore the possibility of using a novel technique, CT perfusion imaging, to monitor the response to anti-tubercular therapy (ATT) in patients with intestinal tuberculosis. MATERIALS AND METHODS: A prospective observational study was performed in adults with treatment naive-intestinal tuberculosis. Clinical, endoscopic, and conventional radiological findings of patients were compared at baseline and post-ATT. CT perfusion imaging was performed with recording of six perfusion parameters (blood flow, blood volume, mean transit time, time to peak, maximum peak intensity, and permeability/blood flow extraction). RESULTS: Twenty-two patients (13 women, 59%) with a median age of 25 years were recruited. The terminal ileum and ileocaecal junction were the most frequent sites of involvement (59%), with multiple segments of the intestine being involved in 16 patients (73%). Median duration of ATT was 6 months (range 6-10 months). Complete clinical response was observed in 22/22 (100%) patients, endoscopic response in 12/12 (100%) patients, and radiological response in 10/13 (76%) patients. There was a significant decrease in mean blood flow, blood volume, maximum peak intensity, and an increase in mean transit time and time to peak on follow-up CT perfusion imaging performed after 6 months of ATT. CONCLUSION: Significant alterations in CT perfusion parameters were demonstrated following treatment, consistent with a decline in inflammation and vascularity. CT perfusion imaging of the bowel is a novel means to assess the radiological response to ATT in intestinal tuberculosis, although at the cost of a higher dose of radiation exposure.

Split bolus dual-energy CT urography after urine dilution: a one-stop shop for detection and characterisation of urolithiasis.

AIM: To determine the diagnostic performance of split-bolus dual-energy computed tomography (CT) urography (SBDECTU) in the detection and characterisation of urolithiasis. MATERIALS AND METHODS: This single-centre Institute Ethics Committee (IEC)-approved prospective study was conducted from April 2014 to November 2015. One hundred and thirty consenting adults with microscopic haematuria underwent dual-energy true non-enhanced CT (DETNE) of the whole abdomen followed by a SBDECTU. The SBDECTU protocol consisted of synchronous nephrogram-urogram acquisition following urine dilution by oral hydration and normal saline injection. Calculi were detected and characterised using virtual non-enhanced (VNE) images derived from SBDECT were compared with DETNE (the reference standard). The subjective image quality and radiation dose were compared. RESULTS: Twenty-six participants had one or more calculi (total 129 calculi) detected on DETNE CT. The sensitivity and specificity of VNE on a per-patient basis were 100%. Of the 129 calculi, 118 were detected on VNE, with a sensitivity of 91.47% and an accuracy of 91.47%. Of the calculi, 83.9% (99/118) could be characterised on SBDECTU images. On VNE images, complete iodine subtraction was seen in 73.1% (19/26). By omitting DETNE CT, the mean dose-length product of 537.6±152.9 mGy and volume CT dose index of 10.9±2.9 mGy•cm2 could have been saved. CONCLUSION: SBDECTU has high diagnostic accuracy in the detection and characterisation of clinically significant urinary calculi at potentially half the radiation dose.

Marrow outside marrow: imaging of extramedullary haematopoiesis.

Extramedullary haematopoiesis (EMH) refers to the formation of non-neoplastic blood cell lines outside the bone marrow and is a common incidental finding when patients with haematological disorders are imaged. EMH presenting as mass (tumefactive EMH) has long been a radiological conundrum as it resembles neoplasms. Several imaging findings have been described in EMH, and these vary depending on the activity of the underlying haematopoiesis. The older lesions are easier to diagnose as they often demonstrate characteristic findings such as haemosiderin and fat deposition. In comparison, the newer, actively haematopoietic lesions often mimic neoplasms. Molecular imaging, particularly 99mTc labelled sulphur colloid scintigraphy, may be helpful in such cases. Although imaging is extremely useful in detecting and characterising EMH, imaging alone is often non-diagnostic as no single mass shows all the typical findings. Hence, a judgement based on the clinical background, combination of imaging findings, and slow interval growth may be more appropriate and practical in making the correct diagnosis. In every case, an effort has to be made in providing an imaging-based diagnosis as it may prevent a potentially risky biopsy. When confident differentiation is not possible, biopsy has to be resorted to. This article describes the causes, pathophysiology, and theories underlying the genesis of EMH, followed by the general and location-specific imaging findings. The purpose is to provide a thorough understanding of the condition as well as enable the clinical radiologist in making an imaging-based diagnosis whenever possible and identify the situations where biopsy has to be performed.

Prostate biopsy: when and how to perform.

Prostate cancer, unlike other cancers, has been sampled in a non-targeted, systematic manner in the past three decades. On account of the low volume of prostate sampled despite the multiple cores acquired, systematic transrectal (TRUS) biopsy suffered from low sensitivity in picking up clinically significant prostate cancer. In addition, a significant number of cancers of the anterior, lateral peripheral zone, and the apex were missed as these areas were undersampled or missed during this biopsy protocol. Subsequently, the number of cores acquired was increased with special focus given to targeting the previously undersampled areas. These procedures led to an increase in the complication rates as well as detection of more clinically insignificant cancers. The advent of multiparametric magnetic resonance imaging (MRI) and its high intrinsic tissue contrast enabled better detection of prostate cancer. This led to the introduction of MRI-targeted biopsies with either MRI-TRUS fusion or under direct (in-gantry) guidance. MRI-targeted biopsies increased the percentage of positive cores and detection of clinically significant prostate cancers; however, these are expensive, time-intensive, require significant capital investment and operator expertise. This article describes the indications, workflow, complications, advantages, and disadvantages of TRUS-guided biopsy followed by MRI-guided biopsies.

Role of radiological imaging and interventions in management of Budd-Chiari syndrome.

Budd-Chiari syndrome (BCS) is a clinical condition resulting from impaired hepatic venous drainage, in which there is obstruction to the hepatic venous outflow at any level from the small hepatic veins to the junction of the inferior vena cava and the right atrium leading to hepatic congestion. The diagnosis of BCS is based on imaging, which can be gathered from non-invasive investigations such as ultrasonography coupled with venous Doppler, triphasic computed tomography (CT) and magnetic resonance imaging (MRI). Apart from diagnosis, various interventional radiology procedures aid in the successful management of this syndrome. In this article, we present various imaging features of BCS along with various interventional procedures that are used to treat this diverse condition.

Multiple intracranial space-occupying lesions in a renal transplant recipient from an area endemic for tuberculosis (TB): TB vs. toxoplasmosis.

Renal transplant recipients may present with intracranial space-occupying lesions (SOLs) due to infections as well as a post-transplant lymphoproliferative disorder (PTLD). Here, we discuss a renal transplant recipient who presented with neurologic symptoms and magnetic resonance imaging (MRI) of the brain showed multiple focal SOLs. Tuberculosis (TB), toxoplasmosis, nocardiosis, fungal infections, and PTLD were considered in the differential diagnosis. MRI spectroscopy was suggestive of an infectious cause, such as toxoplasmosis or TB. Serologic tests using Toxoplasma were negative. A brain biopsy followed by immunohistochemical staining using Toxoplasma antibody demonstrated multiple intravascular cysts of toxoplasma. This case highlights the diagnostic dilemma in an immunocompromised patient with multiple focal brain lesions, especially in areas where TB is endemic.

Diffusion-weighted imaging in urinary tract lesions.

Diffusion-weighted imaging (DWI) utilizes the signal contrast provided by the regional differences in the Brownian motion of water molecules, which is a direct reflection of the cellular micro-environment. DWI emerged as a revolutionary magnetic resonance imaging (MRI) technique in the field of stroke imaging. As far as body imaging is concerned, DWI has come a long way from being an experimental technique to an essential element of almost all abdominal MRI examinations. This progress has been made possible by technical advancements in MRI systems, as well as a better understanding of MRI physics. DWI is quick to perform and has the potential to provide crucial information about the disease process without adding much to the total imaging time. This article provides a brief review of the basic principles of DWI with insights to the information that DWI provides in the evaluation of various diseases of the urinary tract at both 1.5 and 3 T. DWI is helpful for differentiation of various histopathological subtypes of renal cell carcinoma (RCC). Prediction of histopathological grade of RCC is also becoming possible solely based on DWI. Assessment of response to chemotherapeutic agents is possible based on the change in the ADC (apparent diffusion coefficient) value. DWI performed with high b-values increases the confidence in diagnosing prostatic carcinoma. This article highlights the emerging role of DWI in the evaluation of urinary tract lesions.

Multi-modality parathyroid imaging: A shifting paradigm.

The goal of parathyroid imaging in hyperparathyroidism is not diagnosis, rather it is the localization of the cause of hyperparathyroidism for planning the best therapeutic approach. Hence, the role of imaging to accurately and precisely localize the abnormal parathyroid tissue is more important than ever to facilitate minimally invasive parathyroidectomy over bilateral neck exploration. The common causes include solitary parathyroid adenoma, multiple parathyroid adenomas, parathyroid hyperplasia and parathyroid carcinoma. It is highly imperative for the radiologist to be cautious of the mimics of parathyroid lesions like thyroid nodules and lymph nodes and be able to differentiate them on imaging. The various imaging modalities available include high resolution ultrasound of the neck, nuclear imaging studies, four-dimensional computed tomography (4D CT) and magnetic resonance imaging. Contrast enhanced ultrasound is a novel technique which has been recently added to the armamentarium to differentiate between parathyroid adenomas and its mimics. Through this review article we wish to review the imaging features of parathyroid lesions on various imaging modalities and present an algorithm to guide their radiological differentiation from mimics.

Imaging of paediatric liver tumours with pathological correlation.

Paediatric hepatic tumours are relatively rare with malignant lesions being twice as frequent as benign neoplasms and are mostly metastases. Imaging has a significant role in the evaluation of most paediatric liver tumours. Differentiating benign from malignant tumours is important as it significantly affects treatment decisions. We present the characteristic radiological and pathological features of the most common paediatric liver tumours.

Aspergillus colonisation of pulmonary rheumatoid nodules: a rare cause of 'bull's eye' appearance.

Pulmonary rheumatoid nodules [PRNs] are a well described manifestation of rheumatoid arthritis [RA]. Fungal colonisation of these nodules is a rare phenomenon. We report a case of Aspergillus colonisation of multiple cavitary rheumatoid nodules in a young female patient with long-standing seropositive RA with 'bull's eye' appearance on computed tomography [CT]. The 'bull's eye' appearance inside PRNs should raise the suspicion of possible fungal colonisation. In patients with RA, a high index of suspicion for the fungal colonisation should be considered by the clinicians treating pulmonary cavitary nodules.

Update in liver imaging.

Over the last decade, liver imaging has experienced a revolution providing a bewildering array of options for detection and characterisation of liver lesions. Cross-sectional imaging modalities like computed tomography and magnetic resonance imaging have improved in speed and resolution, thereby facilitating multiphasic scanning of the liver. The advent of the use of contrast agents for ultrasonography and magnetic resonance imaging has further paved the way for definitive diagnosis in an attempt to obviate the need for invasive diagnosis. This article captures advances made in ultrasonography, computed tomography, magnetic resonance imaging and positron emission tomography and brings the specialist up to date with the latest in liver imaging.

Role of diffusion weighted imaging in diagnosis of post transplant lymphoproliferative disorders: Case reports and review of literature.

Post transplant lymphoproliferative disorder include a spectrum of conditions occurring in immunosuppressed post transplant recipients, lymphoma being the most ominous. (18)F-fludeoxyglucose positron emission tomography with computed tomography CT) is the current imaging gold standard for lymphoma imaging as it allows both morphological and functional assessment. CT and/or conventional magnetic resonance imaging (MRI) are used for morphological evaluation in transplant recipients. Integrating diffusion weighted imaging with apparent diffusion coefficient analysis in MRI protocol enhances its sensitivity and may prove invaluable in response assessment in transplant recipients.

Mature ovarian teratoma with gliomatosis peritonei--a case report.

Gliomatosis peritonei (GP), a rare condition related to ovarian teratomas, is characterized by miliary implants of mature glial tissues on the peritoneum or omentum. We report herein a case of mature teratoma of the ovary with GP with imaging features and pathological correlation.

Magnetic resonance imaging of the oculomotor nerve.

Oculomotor/cranial nerve III palsy is caused by numerous etiologies involving the brainstem, subarachnoid space, cavernous sinus or superior orbital fissure or orbit. Magnetic resonance imaging (MRI) is the most suitable neuro-imaging technique in patients with this presentation to rule out a mass, aneurysm or ischemic vasculopathy. A pictorial review of various pathologies affecting the oculomotor nerve is presented along with their MRI morphology.

Rheumatoid arthritis: spectrum of computed tomographic findings in pulmonary diseases.

Rheumatoid arthritis (RA) is a common systemic disease that manifests as inflammatory arthritis of multiple joints. Interstitial lung disease (ILD) is the most common manifestation of rheumatoid lung disease. The ILDs associated with RA are diverse and it is very important for the general radiologist to differentiate one from another. There are many other pulmonary diseases apart from ILD. These are associated with a wide spectrum of morphologic changes with substantially different prognoses. The diagnosis of most of these diseases is by clinicoradiological correlation and some of them need pathologic correlation. High-resolution computed tomography helps to characterize and determine the extent of ILD in RA. When interpreting the high-resolution computed tomography of the chest in RA, the radiologist should be familiar with the findings in each entity and comment on activity of the disease, which helps in assessing the prognosis and need for active intervention. This pictorial essay reviews the spectrum of pulmonary diseases in RA and their differential diagnosis.

von Meyenburg's complex in a patient with primary malignancy: role of MRI.

von Meyenburg's complexes are benign liver malformations histologically constituting cystic dilatations of the bile ducts, surrounded by abundant fibrous stroma. Appearance of these lesions on MRI is characteristic and a fine needle aspiration or biopsy can be avoided and judicious management planned. We report a case of esophageal carcinoma who had suspicious lesions in the liver on CT scan, which after MRI were confirmed as biliary hamartomas.

Imaging in bronchopulmonary sequestration.

Bronchopulmonary sequestration is an uncommon pulmonary disorder characterized by an area of non-functioning abnormal lung tissue, which receives its blood supply from a systemic artery and characteristically has no connection with the tracheobronchial tree. The abnormal lung tissue is located within the visceral pleura of a pulmonary lobe in the intralobar variety, whereas the extralobar form has its own visceral pleura. The venous drainage of the extralobar type is usually into the systemic veins, whereas the intralobar type drains into the pulmonary veins. Radiological imaging plays a vital role in establishing the diagnosis, and even more importantly, in providing to the clinician a vascular roadmap essential for surgical planning. We present here a review of bronchopulmonary sequestration and also discuss the role of various imaging methods in the early diagnosis and management of these cases.

Oesophageal duplication cyst: an unusual cause of retrosternal pain and dysphagia in an adult.

Oesophageal duplication cysts in adults are a rare entity and are mostly asymptomatic. We describe the imaging findings in a rare case of oesophageal duplication cyst simulating cold abscess, causing retrosternal pain and dysphagia in a 25-year-old man.