Darshana Sanghvi

Imaging features of extraaxial musculoskeletal tuberculosis

Tuberculosis (TB) continues to be a public health problem in both developing and industrialized countries. TB can involve pulmonary as well as extrapulmonary sites. The musculoskeletal system is involved in 1–3% of patients with tuberculosis. Although musculoskeletal TB has become uncommon in the Western world, it remains a huge problem in Asia, Africa, and many developing countries. Tuberculous spondylitis is the most common form of musculoskeletal TB and accounts for approximately 50% of cases. Extraspinal musculoskeletal TB shows a predilection for large joints (hip and knee) and para-articular areas; isolated soft tissue TB is extremely rare. Early diagnosis and prompt treatment are mandatory to prevent serious destruction of joints and skeletal deformity. However, due to the nonspecific and often indolent clinical presentation, the diagnosis may be delayed. Radiological assessment is often the first step in the diagnostic workup of patients with musculoskeletal TB and further investigations are decided by the findings on radiography. Both the radiologist and the clinician should be aware of the possibility of this diagnosis. In this manuscript we review the imaging features of extraspinal bone, joint, and soft tissue TB.

Pancreatic tuberculosis: A clinical and imaging review of 32 cases

Background: Tuberculosis of the pancreas is a rare entity, and anecdotal reports describing imaging features of pancreatic tuberculosis have been described in medical literature. The imaging features including computed tomography (CT) and ultrasonography in diagnosed cases of tubercular involvement of the pancreas are described, with an overview of clinical features and laboratory investigations. Materials and Methods: We analyzed records of 384 patients of diagnosed cases of abdominal tuberculosis for involvement of pancreas and detected 32 patients (8.33%) who had pancreatic involvement. This included 22 men and 10 women with an age range of 19 to 64 years (mean age of 42.5 years), who were detected to have pancreatic tuberculosis from 1999 to 2004 in our institute. We reviewed the clinical, radiologic (ultrasonographic and CT features), and laboratory findings of all patients. The criteria for diagnosis of tuberculosis were based on ascitic fluid adenosine deaminase level in 14 patients, fine-needle aspiration cytology of lymph nodes in 9 patients, and presence of pulmonary tuberculosis on chest radiograph, which was found in 9 patients. On follow-up, 6 months after antituberculous treatment, 25 patients showed response to anti-Kochs treatment, 3 patients had drug-resistant tuberculosis, 2 patients died, and 2 patients were lost to follow-up. Results: The male/female ratio was 2.2:1. The maximum number of patients was in the fourth decade (30-39 years). The duration of symptoms was spanning between 2 and 11 months, with a mean duration of 6 months. The most common symptom was abdominal pain localized to the epigastrium. Sixteen patients were seropositive for HIV-1 infection. Fourteen patients had history of tuberculosis of the lungs, whereas 18 patients had pancreatic and peripancreatic involvement as the primary manifestation. Ultrasonography showed bulky inhomogenous pancreas in 5 patients; solitary or multiple hypoechoic collections were observed in all 7 and 20 patients, respectively. CT findings demonstrated hypodense collections within the pancreas associated with peripancreatic lymphadenopathy in 29 patients. Three patients had a complex pancreatic mass lesion. Conclusions: Pancreatic tuberculosis can present with a variable spectrum of imaging findings. Tuberculosis of the pancreas should be considered as a diagnostic possibility in patients who present with a pancreatic space occupying lesion associated with peripancreatic lymphadenopathy.

Malignant brachial plexopathy: A pictorial essay of MRI findings

For imaging, the brachial plexus is a technically and anatomically challenging region of the peripheral nervous system. MRI has a central role in the identification and accurate characterization of malignant lesions arising here, as also in defining their extent and the status of the adjacent structures. The purpose of this pictorial essay is to describe the MRI features of primary and secondary malignant brachial plexopathies and radiation-induced brachial nerve damage.

Case Series: Cyclops lesion - extension loss after ACL reconstruction.

Localized anterior arthrofibrosis (cyclops lesion) is the second most common cause of extension loss after anterior cruciate ligament (ACL) reconstruction. We present and discuss two patients with prior ACL reconstructions, who presented with pain and loss of extension following surgery. MRI and arthroscopy of the knee revealed typical features of a cyclops lesion. The patients showed significant symptomatic improvement following arthroscopic resection of these lesions.

Post-treatment imaging of high-grade gliomas

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.

Imaging of cartilage repair procedures

The rationale for cartilage repair is to prevent precocious osteoarthritis in untreated focal cartilage injuries in the young and middle-aged population. The gamut of surgical techniques, normal postoperative radiological appearances, and possible complications have been described. An objective method of recording the quality of repair tissue is with the magnetic resonance observation of cartilage repair tissue (MOCART) score. This scoring system evaluates nine parameters that include the extent of defect filling, border zone integration, signal intensity, quality of structure and surface, subchondral bone, subchondral lamina, and records presence or absence of synovitis and adhesions. The five common techniques of cartilage repair currently offered include bone marrow stimulation (microfracture or drilling), mosaicplasty, synthetic resorbable scaffold grafts, osteochondral allograft transplants, and autologous chondrocyte implantation (ACI). Complications of cartilage repair procedures that may be demonstrated on magnetic resonance imaging (MRI) include plug loosening, graft protuberance, graft depression, and collapse in mosaicplasty, graft hypertrophy in ACI, and immune response leading to graft rejection, which is more common with synthetic grafts and cadaveric allografts.

Three distinct co-existent primary brain tumors in a patient.

A rare case of simultaneous occurrence of three entirely distinct intracranial tumors is described. A 55-year-old male with no evidence of phacomatoses or history of radiation therapy presented with complaints of increased drowsiness, headaches, and dysarthria. Investigations revealed an olfactory groove meningioma, a glioblastoma multiforme in the left medial temporal lobe, and a diffuse glioma in the brain stem. Occurrence of multiple varieties of tumors at the same time is extremely rare. Theories that explain their occurrences including the role of common carcinogens, autocrine growth factors, and tumor suppressor genes are discussed.

Vigabatrin-induced reversible changes on magnetic resonance imaging of the brain.

A 7‐month‐old girl presented with seizures at 3 months of age. Initially, the seizures were focal clonic and treated with carbamazepine. At 4 months of age, she developed IS and was started on VGB (135 mg/kg/day). An MRI of the brain was requested to evaluate the cause of IS. The patient had completed 6 weeks of VGB therapy at the time of the MRI study. Symmetric restricted diffusion was seen in the globi palladi, thalami and dorsal brainstem along the dorsal tegmental tracts [Figure 1]. Clinical reassessment showed no corresponding new symptoms or examination findings to explain the signal alterations in the deep grey nuclei and brainstem. Also noted were focal areas of polymicrogyria in the right frontal and left temporal lobes [Figure 2], explaining the probable etiology of IS. In view of the changes seen on MRI, VGB was withdrawn. A repeat MRI was performed 8 weeks after the withdrawal of VGB; it showed resolution of the above mentioned findings, establishing the reversible nature of these MRI changes [Figure 3].

Stand alone mechanical thrombectomy (with penumbra system) for acute ischemic stroke based on MR imaging: Single center experience

BACKGROUND There is dismal rate of recanalization following intravenous thrombolysis of large vessel occlusive ischemic stroke. Trials on use of mechanical clot retrievers in acute ischemic stroke have used time from onset and clinical deficit at presentation as the main indications for intervention. MATERIALS AND METHODS Retrospective analysis of case records of acute stroke seen between May 2009 and October 2011 was done. It revealed 23 patients with acute ischemic stroke treated by mechanical thrombectomy using Penumbra system (PS). We used magnetic resonance (MR) imaging in correlation with clinical presentation to determine patients likely to benefit from recanalization and accordingly offered or at times deferred revascularization. A comparison of approach and outcomes was done with other relevant trials/reports. RESULTS Recanalization was achieved in all but one patient. Median modified Rankin Scale (mRS) score at 90 days was 2. Good clinical outcome (mRS ≤ 2) was achieved in 56.5% compared with 25% in Penumbra pivotal trial and 36% in multi Mechanical Embolus Removal in Cerebral Ischemia (multi MERCI) trial. All cause mortality was 13.04%. Symptomatic intracerebral hemorrhage (ICH) occurred in two patients (8.6%). CONCLUSION Analysis of our results suggests that PS is safe and effective (91.3%) in recanalizing cerebral vessels without concomitant thrombolytics.