Shanmuga Sundaram Palaniswamy

Dacryoscintigraphy: an effective tool in the evaluation of postoperative epiphora.

Background and aimDacryoscintigraphy is a grossly underutilized nuclear medicine procedure for assessing the patency of nasolacrimal ducts. It is an alternate noninvasive modality requiring no added expertise when compared with dacryocystography, an invasive radiological counterpart. Dacryocystorhinostomy (DCR) is a surgical procedure in which a patent rhinostomy is made so that a low-pressure lacrimal bypass system is created, thus relieving epiphora, dacryocystitis or mucocele. DCR has been accepted as a highly successful procedure in the management of epiphora from nasolacrimal duct obstruction; however, adverse local effects can reproduce epiphora. This study highlights the utility and simplicity of dacryoscintigraphy in the postoperative setting of DCR, apart from showcasing its high sensitivity and accuracy in localizing the sites of lacrimal drainage obstruction. Materials and methodsFifty-five postoperative patients of DCR were screened. Ten volunteers constituted the control group. One drop (10 &mgr;l) of technetium pertechnetate (99mTcO4) was instilled simultaneously in the outer canthus of both eyes (50–100 &mgr;Ci). Upright dynamic (8 min) and anterior static images of the eyes (up to 20 min) were acquired on a gamma camera fitted with a high-resolution collimator. Physiological interventions that were used in this study were eye blinking, saline intervention, and lacrimal sac massaging. ResultsOut of 40 symptomatic DCR patients, 22 had complete obstruction at the presac level and 18 patients had partial obstruction. Quantitative parameters like tear transit time and lacrimal sac half-life were also calculated. After massage of the lacrimal sac, progression of the tracer was observed in five patients. Premassage and postmassage tear column measurements showed a relative increase of 30.1%. Massage of eight clinically normal ducts showed a relative increase of 2.4% (P=0.06). Statistical analysis using the Fisher test shows very significant concordance between clinical symptoms and dacryoscintigraphy findings in postoperative DCR patients (P<0.0001). The modified McNemar’s pair test did not show statistically significant differences between dacryoscintigraphy and the syringing irrigation test. ConclusionDacryoscintigraphy is a simple and easy-to-perform investigation providing high sensitivity in epiphora detection in patients after DCR. Interventions play a role in further enhancing the sensitivity of the technique. This study demonstrates the utility of dacryoscintigraphy in detecting subclinical and partial lacrimal duct obstruction with good patient compliance. It provides an easy and effective way of screening families, enabling an early diagnosis. During imaging, a high-resolution collimator is found to be an efficient substitute for the conventional pinhole collimator.

Papillary carcinoma thyroid with uveal metastases.

Ocular metastases secondary to thyroid cancer are extremely uncommon, typically affecting the orbit rather than the globe and uvea. Within the uveal structures, the choroid is more commonly involved than the iris and ciliary body. We present a 56-year-old male patient who underwent total thyroidectomy for metastatic papillary thyroid carcinoma (PTC), solid variant. Whole-body(131) I (WBI) scintigraphy was performed and the patient was treated twice with high-dose (131)I therapy. WBI after the second treatment demonstrated right orbital activity. The patient developed sudden onset of right eye diminished vision and was diagnosed with uveal (choroidal) metastases from PTC.

Cardiac fatty acid metabolism and ischemic memory imaging with nuclear medicine techniques.

There has been a dramatic improvement in the clinical management of myocardial diseases with the advent of cardiac metabolic and molecular imaging. Although both myocardial perfusion and metabolic imaging provide insight of myocardium at risk for infarction or ischemia, it is known that metabolic derangements precede perfusion abnormalities, especially after reperfusion therapy. Deranged myocyte loses its flexibility of choosing the right substrate for energy production and it switches its substrate, especially between fatty acid (FA) and glucose depending on disease condition; for example, predominance of FA metabolism is noted in diabetic heart disease, whereas glucose metabolism is enhanced in pressure overload conditions such as left ventricular hypertrophy. We thus hypothesize that with better technological advancements and different substrates, the metabolic footprint of various heart diseases can be charted out in future to help in the optimization of patient management. This review attempts to discuss the importance of radionuclide-labeled FAs in cardiac metabolic and ischemic memory imaging.

A Gluten-Free Vegan Meal for Gastric Emptying Scintigraphy: Establishment of Reference Values and Its Utilization in the Evaluation of Diabetic Gastroparesis

Purpose The aim of this study was to describe the preparation of radiolabeled idli (savory cake) meal for use as an alternate to the egg white sandwich (EWS) meal in gastric emptying scintigraphy (GES). Furthermore, the aim of this study was to establish normal emptying rates for this meal and present our experience in using it in the evaluation of diabetic gastroparesis. Patients and Methods The meal was prepared using a universally available packaged mix labeled with 1 mCi 99mTc sulfur colloid, and the stability of labeling was tested up to 4 hours in simulated gastric fluid. One hundred thirteen healthy volunteers (aged 20–78 years; 54 women, 59 men) underwent GES study using the idli meal. Gastric retention at one-half, 1, 2, and 4 hours after ingestion of the meal was estimated, and the normal limits were set using the fifth and 95th percentile values at each period. Having established its normal emptying rates, the idli meal was further used to evaluate 70 patients suspected with diabetic gastroparesis. Results The idli meal, with a calorific value ≈282 kcal, has a relatively higher fat content (8% of total mass) than EWS. More than 96% of 99mTc sulfur colloid remained bound to the meal after 4 hours suspension in simulated gastric fluid. Gastric retention greater than 30% and greater than 6% at 2 hours and 4 hours, respectively, indicated delayed gastric emptying, whereas retention less than 30% at 1 hour suggested rapid emptying. Among patients suspected with diabetic gastroparesis, delayed gastric emptying was identified in 76%, and rapid emptying was seen in 4.2%. Conclusions Radiolabeled idli meal is a good alternative to EWS meal for routine GES, especially among patients with specific dietary restrictions.

Lymphoscintigraphy in Unilateral Lower Limb and Scrotal Lymphedema Caused by Filariasis

Lymphedema is the edema that results from chronic lymphatic insufficiency. Lymphatic filariasis is caused by the filarial nematodes Wuchereria bancrofti, Brugia malayi, and Brugia timori. Lymphatic filariasis is common in tropical and subtropical regions. Early diagnosis and prompt therapy can be implemented using lymphoscintigraphy. Our patient is a 15-year-old boy presenting with a 3-month history of hydrocele. The patient was referred to us to rule out any lower limb lymphatic obstruction as the patient is from an endemic area. Tc Sulfur colloid (filtered) lymphoscintigraphy showed abnormal tracer collection in the scrotum and penis. There is associated dermal backflow or stasis in the left thigh region extending just above the knee, suggesting partial obstruction of left inguinal lymphatic channels.

Zosteriform cutaneous metastases from an occult primary malignancy of lung identified by whole-body FDG PETCT imaging

Cutaneous metastasis may be the first evidence of internal malignancy or a sign of recurrence of malignancy and is considered a grave prognostic sign. There are various morphological variants of cutaneous metastases, with the most common being solitary to multiple erythematous infiltrating papules and nodules and the rarer variants being carcinoma erysipeloides, carcinoma en cuirasse, carcinoma telangiectaticum, alopecia neoplastica, metastasis to the inframammary crease, and zosteriform pattern. FDG PETCT is an established imaging modality in the identification of an unknown primary malignancy and also has an important role in the therapeutic decision-making.

Coronary Stent Infection Successfully Diagnosed Using 18F-Flurodeoxyglucose Positron Emission Tomography Computed Tomography.

Infection of coronary stents is extremely rare. We report a case of a 60-year-old gentleman with recurrent fever after acute stent occlusion and reintervention. A coronary angiogram showed an occluded stented segment and the blood cultures were positive for infection. The presence of inflammation in the stented region was confirmed using 18F-flurodeoxyglucose positron emission tomography computed tomography. The patient underwent surgery and the diagnosis was proven by examination of the surgical material. This article highlights the need to have a high index of suspicion of stent infection, and the use of 18F-flurodeoxyglucose positron emission tomography computed tomography along with coronary angiogram in aiding the diagnosis.

Dual Time Point 18F-FDG PET/CT Imaging Identifies Bilateral Renal Tuberculosis in an Immunocompromised Patient with an Unknown Primary Malignancy

18F-FDG PET/CT imaging is an established imaging modality for cancer staging and response assessment. Its role in identifying infective and inflammatory pathologies from malignancy is debated. Dual time - point imaging is a refined technique used to overcome this interpretational dilemma. We present a 59 year old male with an unknown primary malignancy who was referred for a 18F-FDG PET/CT imaging. Images revealed primary lung malignancy with co existing bilateral renal tuberculosis which otherwise would have gone amiss or would have been considered as metastases.

Ventilation/Perfusion scan aids in the diagnosis of diabetes mellitus induced trepopnea due to isolated right phrenic nerve palsy

Dyspnea can rarely be due to diabetes mellitus induced neuropathy. The term “trepopnea’ is sparingly used in clinical practice and refers to dyspnea on assuming a particular lateral decubitus position Trepopnea is rarely described in association with unilateral diaphragmatic paralysis, which in itself is an uncommon cause of respiratory distress. We report a 27-year-old diabetic female who presented with sudden onset of dyspnea. On close interrogation, patient complained of dyspnea that was exaggerated while lying on the left side (left lateral decubitus position). A fluoroscopic sniff test showed a paradoxically moving right diaphragm confirming the diagnosis of unilateral diaphragmatic paralysis attributed to diabetes induced isolated phrenic nerve palsy. This case highlights the importance of ventilation — perfusion imaging in non-pulmonary etiologies and also attaches importance in recognizing trepopnea as an early clinical symptom of diaphragmatic paralysis. This case illustrates that diabetic neuropathy due to isolated phrenic nerve palsy can occur in the absence of peripheral neuropathy and that glycemic control is unrelated to the manifestation or severity of this disease.

Multilocular disseminated Tarlov cysts: Importance of imaging and management options

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 this case 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 lumbosacral and dorsal TCs can produce nerve injuries and serious movement disturbances, and (3) to document the usefulness of the magnetic resonance imaging and bone scan in non-invasive diagnosis and guiding management in such cases. These cysts are clearly identified by magnetic resonance imaging (MRI) and computerized tomography imaging of the lumbosacral spine. However, there are no reports on the scintigraphic findings of multilocular disseminated TC in literature. TCs are typically benign, asymptomatic lesions that can simply be monitored. To date, no consensus exists about the best surgical strategy to use when indicated.