P Shanmuga Sundaram

Role of myocardial perfusion single photon emission computed tomography in pediatric cardiology practice.

Diagnostic and prognostic power of myocardial perfusion imaging in patients with coronary artery disease has been demonstrated with planar imaging which was further improvised with addition of gated SPECT and newer Technetium labeled myocardial perfusion tracers like SestaMIBI, Tetrofosmin. Myocardial perfusion abnormalities at rest and after stress are considered to be the best predictors of cardiac event–free survival in adults with ischemic heart disease. This article highlights various myocardial perfusion imaging (MPI) radiopharmaceuticals, exercise procedures, pharmacological stress protocols, indications for MPI and myocardial perfusion patterns in children with some of the common congenital and acquired heart diseases.

Current practice and recommendation for presurgical cardiac evaluation in patients undergoing noncardiac surgeries.

The increasing number of patients with coronary artery disease (CAD) undergoing major noncardiac surgery justifies guidelines concerning preoperative cardiac evaluation. This is compounded by increasing chances for a volatile perioperative period if the underlying cardiac problems are left uncorrected prior to major noncardiac surgeries. Preoperative cardiac evaluation requires the clinician to assess the patients probability to have CAD, severity and stability of CAD, placing these in perspective regarding the likelihood of a perioperative cardiac complication based on the planned surgical procedure. Coronary events like new onset ischemia, infarction, or revascularization, induce a high-risk period of 6 weeks, and an intermediate-risk period of 3 months before performing noncardiac surgery. This delay is unwarranted in cases where surgery is the mainstay of treatment. The objective of this review is to offer a comprehensive algorithm in the preoperative assessment of patients undergoing noncardiac surgery and highlight the importance of myocardial perfusion imaging in risk stratifying these patients.

Radioiodine as an adjuvant therapy and its role in follow-up of differentiated thyroid cancer

Papillary and follicular cancers of thyroid are the most common varieties of differentiated thyroid cancers exhibiting excellent long-term prognosis when carefully managed. Being a slow-growing malignancy, guidelines exist on the staging, preoperative risk stratification, and management of these cancers to increase the overall survival of these patients. Radioactive iodine has a central role in differentiated thyroid malignancies. It has the same physical properties as stable iodine, thus both normal and malignant thyrocytes cannot differentiate radioactive from stable iodine. Differentiated thyroid carcinoma (DTC) cells concentrate cytocidal amounts of Iodine -131 (131 I) by trapping (the function of the sodium iodine symporter, or NIS) and organifying the iodide ion to produce levothyroxine and triiodothyronine. We shall discuss the role of radioiodine in the management and followup of DTC patients.

Multilocular disseminated tarlov cysts: importance of imaging

With technological advancements and wider availability of multimodality imaging, incidental lesions are frequently identified in patients undergoing various imaging studies. We report here a case of multiloculated disseminated perineural or Tarlov cysts (TCs). The primary aim of our study was to (1) provide a comprehensive review of the clinical, imaging and histopathological features of TCs (2) to draw attention to the fact that multiple lumbo-sacral and dorsal TCs can produce nerve injuries and serious movement disturbances (3) to document the usefulness of the magnetic resonance imaging (MRI) and bone scan in noninvasive diagnosis and guiding management in such cases. These cysts are clearly identified by MR and computerized tomography imaging of the lumbosacral spine. However, there are no reports on the scintigraphic findings of TCs in literature. TCs are typically benign, asymptomatic lesions that can simply be monitored. Until date, no consensus exists about the best surgical strategy to be followed for their management.

Scintigraphic Evaluation of Swallowing

Swallowing or deglutition is a process of propulsion of food from the oral cavity into the stomach. It is classified into oral, pharyngeal and esophageal stages according to the location of the bolus. The oral stage is subdivided into oral preparatory and oral propulsive stages which are under voluntary control, whereas the next two stages, the pharyngeal and esophageal stages, are involuntary, being under reflexive control.

Hughes syndrome with cerebral, skeletal infarction & retinal vein thrombosis.

A 23-year old female patient presented to the General Medicine and Nuclear Medicine departments of Amrita Institute of Medical Sciences, Cochin, Kerala, India in March 2013 with fever, joint pains for six months duration with thrombocytopenia. Immunologically she was tested positive for systemic lupus erythematosis (SLE). A Technetium 99m (Tc 99m)-methylene diphosphonate (MDP) bone scan was advised. Images revealed unsuspected cold defects in D6 and L4 vertebral bodies raising the suspicion of bone infarcts versus marrow metastatic infiltration. The patient showed no evidence of polyarthritis. However, there was evidence for left frontal lobe acute infarction on the MRI (magnetic resonance imaging) (Fig. 1). Whole body (methoxy-iso butyl-isonitrile) MIBI oncoscintigraphy (Figs ​(Figs22 and ​and3)3) was suggested to re-assess the above bone scan findings. The patient developed sudden onset painless diminution of vision two weeks later. Ophthalmological examination revealed retinal vein thrombosis on right side. Fig. 1 MRI of brain shows features of acute infarct in left frontal lobe (arrow). Fig. 2 Whole body MIBI oncoscintigraphy and 99mTc MDP whole body skeletal scintigraphy showed cold defects in D6 and L4 vertebral bodies confirming scintigraphic diagnosis of bone infarcts. Fig. 3 99mTC MDP bone SPECT CT (single photon emission computed tomography - computed tomography) images of dorsolumbar vertebrae showing cold defects in D6 and L4 vertebral bodies. The patient had persistent severe thrombocytopenia to the tune of 15,000 per microliter and elevated serum creatinine of 1.3 mg/dl. The possibilities considered were severe lupus activity with relapse, thrombotic thrombocytopenic purpura (TTP) or severe antiphospholipid antibody syndrome. To rule out TTP, lactate dehydrogenase level was measured which was elevated, but peripheral smear was non contributory ruling out the diagnosis of TTP. She was given three pulses of high-dose steroid despite further deterioration in her platelet counts. Her anticardiolipin antibody titres were positive on two occasions 12 wk apart to the titre of 25-30 MPL units confirming the diagnosis of Hughes syndrome rather than SLE induced bone infarction. The patient was started on intravenous (iv) Heparin (1000 units per hour), titrated based on activated partial thromboplastin time (APTT) values with which she started responding. Platelet counts also stabilized. The patient was doing well at two months follow up.

Primary peripheral neurolymphomatosis mimicking synovial sarcoma: FDG PETCT to the rescue.

Our understanding of the association between synovial sarcoma and peripheral neurolymphomatosis is limited to a few case reports in literature. Delay in diagnosis or misdiagnosis is possible due to its insidious onset and varied presentation compounded by non-specific imaging findings. Needle biopsy also may not be confirmatory especially, in cases of biphasic sarcoma as in our case, and it may be necessary to proceed to open biopsy. Here, is a case of a non-tender right calf muscle mass, which was reported as biphasic synovial sarcoma by FNAC. Positron emission tomography computed tomography-computed tomography (PETCT) showed right sciatic nerve involvement and multiple infra diaphragmatic lymph nodal lesions. Intensity of (18)F FDG ((18)Flourine labeled fluro de oxy glucose) uptake and the infra diaphragmatic lymph nodal lesions distribution, was more in favour of a lymphoma diagnosis rather than a sarcoma, (which are usually low metabolically active tumors). Thus, this case highlights the usefulness of FDG PETCT in arriving at a diagnosis in the background of indeterminate clinicopathological and radiologic findings.

Unsuspected Right Lobe Liver Infarction in Byler’s Disease – Identified by Hepatobiliary Scintigraphy

To the Editor: Wepresent a 6-y-old girl with intractable itching all over the body, who was diagnosed as progressive familial intrahepatic cholestasis, PFIC. Living donor liver transplantation was performed. On 7th postoperative day, patient developed abdominal pain and high fever. Ultrasound examination was non contributory. A hepatobiliary scintigraphy (HBS) was requested to look for bile leak. HBS showed photopenic areas in perihepatic region, along resected margin and medial aspect of liver, which was further confirmed by SPECT/CT (Single photon emission computed tomography/computed tomography) images. 99mTc HBS imaging, thus raised the possibility of right lobe liver infarction based on the clinical and scintigraphic findings of infarction (Figs. 1 and 2). 64 slice CT abdomen reconfirmed this finding (Fig. 3). PFIC, is an autosomal recessive, cholestatic disorder affecting children within 3 mo of age. It is characterized by defect in draining bile from liver [1, 2]. Partial external biliary diversion (PEBD) is the treatment of choice. Liver transplantation is the only definite therapy for progressive liver failure and intractable pruritis [3]. Postoperative hepatic infarction due to hepatic artery thrombosis (HAT) is rare in pediatric patients. When present, this portends further complications like sepsis, abscess, bile leak, bile duct strictures, and ultimately allograft failure. Incidence of HAT in liver allograft recipients is only 7.4 % [1, 2]. As the clinical manifestations of HAT are invariably nonspecific, imaging plays a crucial role in early identification. At times, patient may need a re-transplantation. Ultrasonography and Doppler imaging are usually the first line of investigations [4]. Although CT demonstrates a well demarcated, wedge shaped, low attenuation lesion extending toward the hepatic periphery, the appearance is not totally specific for

MDP bone scan in the early identification of polyarticular aspergillosis

Figure 1. (A) 20 millicurie of Tc-MDP was injected intravenously and 3 h later whole body anterior and posterior images were acquired on a dual-head variable-angle gamma camera. Images show hot spots in the right sacroiliac, hip, and right knee joints (arrows). (B) Magnetic resonance image of the pelvis (T2-STIR: ‘short TI inversion recovery’ is an inversion recovery pulse sequence with specific timing so as to suppress the signal from fat, for better soft tissue visualization) was later done, and showed a hyper-intense signal in the right sacroiliac joint and hip joint with post-contrast enhancement.