Incidental diagnosis of intestinal perforation on a 99mTc DTPA renogram.

Perforation of the bowel can be a life-threatening condition and is usually clinically diagnosed when a patient presents with such features as severe abdominal pain, tenderness, and tachycardia. Bowel perforation may be corroborated by various conventional imaging modalities, including X-ray, ultrasonography, computed tomography, and magnetic resonance imaging. Nuclear medicine imaging modalities seldom have a role to play in these settings. Rarely diagnosis of perforation may be missed if it is concealed and does not present with the usual signs. Mostly the perforation will eventually be diagnosed if they develop signs and symptoms and is taken up for an exploratory laparotomy. A delay in diagnosis can later lead to significant patient morbidity or even mortality. This report describes a case where possible intestinal perforation was suspected on a 99mTc-DTPA renogram in a postoperative patient with significant urine leak, the presence of which was confirmed intraoperatively. To our knowledge, this was the first such case in the literature.

18F-FDG PET CT in cardiac device infections - A Case series.

With the increasing number of interventional cardiology procedures, the number of cardiac device infections (including pacemakers, prosthetic valves, coronary and aortic stents) have also increased. These infections can cause significant morbidity and can even lead to mortality if not managed promptly. If suspected clinically the first-line imaging modality is Trans-Thoracic Echocardiography, while Transesophageal Echocardiography is also used in selected cases. The confirmation of a cardiac device infection is mostly done with the help of blood or pus culture. Even though Echocardiography is a very efficient technique for the evaluation of the heart, it cannot differentiate infection from thrombus or fibrosis. With the increasing availability of Positron Emission Tomography CT (PET CT) machines worldwide, the use of 18F-FDG PET CT for infection imaging has gained traction, especially for cardiac device infection. Most of the recent studies show a good diagnostic accuracy of 18F-FDG PET CT with many of the recent diagnostic and management guidelines now acknowledging its role, especially in equivocal cases. We present six such cases where 18F-FDG PET CT provided valuable information either for diagnosis, confirming the presence of infection, delineating extent, therapy response or sometimes even helping appropriate treatment decision making in patients with suspected cardiac device infection.

18F-FDG PET imaging for treatment response assessment and management guidance in patients with skull base osteomyelitis.

OBJECTIVE: The objective of this study is to evaluate the role of hybrid 18F-FDG PET for treatment response assessment and management guidance in patients with skull base osteomyelitis. MATERIALS AND METHODS: Retrospectively, 33 patients, with at least a baseline and follow-up PET (computed tomography/MRI) scan, were included. Parameters like standardized uptake value (SUV) max, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) (initial, follow-up, percentage change) were analysed and outcomes based on 18F-FDG PET reports were classified into resolution (a), partial response (b), progression (c) and stable disease (d). The clinical course and response on anatomical imaging were also compared with 18F-FDG PET. RESULTS: There was mild correlation between initial SUV with ESR (0.338) and CRP (0.384). Moderate correlation was seen between follow-up SUV and CRP (0.619), percentage change in SUV max (PC SUV) with percentage change in ESR (0.456) and CRP (0.668). Mean PC SUV was 70% (a), 35% (b), -40% (c) and -18% (d), respectively. 48% (16/33) (resolution, progression, stable disease) patients had clear management change with 18F-FDG PET with either escalation or stopping of antibiotics/antifungals. Management decision in partial response group (52%, 17/33) was taken clinically. On retrospective PC SUV analysis, treatment continuation group (8 patients) showed 20% decrease, whereas the group that was only monitored further (9 patients) had 48% reduction in SUV. CONCLUSION: 18F-FDG PET showed a moderate association with clinical markers used in follow-up of patients with skull base osteomyelitis and is a reliable investigation for assessment of disease status. This can be used as a guide along with clinical evaluation for de-escalation of treatment.

Role of 18 F-FDG-PET/CT in an AML-M5a Subtype Patient with Rare Constellation of Hemophagocytic Lymphohistiocytosis & Bilateral Multiple Breast Chloromas.

We report a treated case of acute myeloid leukemia (AML-M5a subtype) with monocytic differentiation (AMoL) presenting with fever and body pains. Initial 18 F-FDG-PET/CT ( 18 F-flurodeoxyglucose positron emission tomography/computed tomography) identified multiple lymph nodal, and marrow lesions. Biopsy confirmed hemophagocytic lymphohistiocytosis (HLH). Post HLH treatment, follow-up PET/CT demonstrated unsuspected FDG avid bilateral breast lesions ( n = 5), which proved to be chloromas, that is, extranodal manifestation of AML. 18 F-FDG-PET/CT has helped not only in identifying the various sites of disease involvement but also in guiding the sites for biopsy. Finally, 18 F-FDG-PET/CT was useful in monitoring therapy response for both these coexisting pathologies, which are said to be resistant to treatment based on FLT3-ITD tyrosine kinase-3 internal tandem duplication mutation positivity and high-grade AML status. This case represents a rare constellation of different etiologies that needed to be differentiated. It also emphasizes the challenges in interpreting PET/CT findings, especially in difficult clinical scenarios. Disease distribution in HLH/presence of chloromas, etc., can mimic stage IV lymphoma in a known case of AML. So the nuclear medicine physician should be aware of the different complications in the background of AML, especially in patients with poor prognostic factors.

18 F-FDG Whole-Body PET-MR in Primary Hepatic Lymphoma Mimicking Focal Nodular Hyperplasia.

Primary hepatic lymphomas are rare hepatic malignancies which are often misdiagnosed preoperatively. Early accurate diagnosis is essential as the patients can be treated successfully with chemotherapy, eluding the need for surgery. We present a case of primary hepatic lymphoma which mimicked as focal nodular hyperplasia with normal biochemical tumor markers, and 18 F-fluorodeoxyglucose ( 18 F-FDG) whole-body positron emission magnetic resonance showed intense FDG uptake in the large hepatic lesion. The patient subsequently underwent right hepatectomy, and histopathology revealed diffuse large B cell lymphoma.

Atypical Presentation of Marginal Zone Lymphoma as Isolated Diffuse Bone Marrow Involvement: Utility of F-18 FDG PET/CT in Diagnosis and Response Assessment.

Non-Hodgkin's lymphoma (NHL) with secondary bone marrow involvement is relatively common. However, isolated involvement of bone marrow in marginal zone type of NHL is atypical and rare. Here, we describe a patient of atypical marginal zone lymphoma with isolated bone marrow involvement who presented with weight loss and bicytopenia, where F-18 FDG PET/CT (fluorine-18-labeled fluorodeoxyglucose positron emission tomography with computed tomography) imaging played a pivotal role in establishing the diagnosis when conventional imaging modalities were unremarkable. The patient was successfully treated with systemic chemotherapy (rituximab, cyclophosphamide, prednisolone) and achieved complete remission, as demonstrated by a follow-up F-18 FDG PET/CT scan.

Recurrent Intra Articular Osteochondroma of Left 4th Finger.

Osteochondromas are common benign bone tumors arising from metaphyseal region of long bones. They are notorious for undergoing malignant transformation. We present a case of a middle aged woman with recurrent episodes of swelling in the middle of left 4th finger post excision. Bone scan was performed to look for any malignant transformation of finger lesion and also to rule out skeletal metastases due to recent onset bone pains. 99m Tc MDP (Technetium methylene diphosphonate) bone scan demonstrated a focal hot spot in middle of left 4th finger along the radial side. There was no evidence of skeletal metastases. Surgery is usually curative (70-90%). Limb sparing wide local excision is treatment of choice.

Early Demonstration of Spontaneous Perinodal Lymphangiogenesis by Lymphoscintigraphy after Vascularized Lymph Node Transplantation - A Pilot Study.

Background: Despite the lymphatic system being so important and extensive, the field of lymphatic diseases, research is still very young. Lymphedema is a progressively debilitating condition with no known "cure." Specific pathologies that could benefit from improved lymphatic drainage by advanced super surgical techniques or engineered tissue transfer are being sought. Microsurgical techniques like lymphovenous bypass and anastomosis have spurred interest as they tend to physiologically restore the damaged lymphatic channels and may be a key to permanent cure. The latest in the field is vascularized lymph node transfer (VLNT), indicated in post mastectomy or other post operative settings producing disruption of regional lymphatic channels and draining lymph nodes. Autologous healthy lymph nodes are transferred along with surrounding fat and vascular pedicle to the affected limb in a bid to promote lymphangiogenesis. Lymphoscintigraphy (LS) is a simple, noninvasive nuclear technique used in identifying upper or lower limb lymphatic dysfunction and obstruction with a high degree of sensitivity. Quantitative LS is extremely useful in follow-up assessment of lymphedema postmanual lymphatic drainage (MLD) or other forms of medical management. Aim: We hypothesize that LS can document perinodal lymphangiogenesis post VLNT. Material and Methods: Three cases of acquired lymphedema (suspected filariasis and postmastectomy conditions) who underwent VLNT in our institute were prospectively studied with LS. The imaging findings highlight the subtle lymphatic regeneration along with the vascularized graft in all three patients during the early postoperative period. Conclusion: This is the first (pilot) study documenting early spontaneous perinodal lymphangiogenesis after VLNT in human subjects.99mTc Nanocolloid LS has been found to be incremental in demonstrating early lymphangiogenesis.

Utility of Fluorine-18-Labeled Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Diagnosis of Erdheim-Chester Disease with Multisystemic Involvement.

Erdheim‒Chester disease (ECD) is a rare non-Langerhans' cell histiocytic proliferative disorder of unknown origin with multisystemic predilection. It commonly affects adults in the fifth-seventh decades of life, with male preponderance, and has nonspecific clinical manifestations. Presence of characteristic radiological findings and demonstration of CD68 positive xanthogranulomatous infiltrates in histology clinches the diagnosis. Nevertheless, being a nonmalignant condition, it might be fatal due to multiorgan dysfunction. Hence, timely diagnosis and initiation of treatment with corticosteroids, immunosuppressants, or tyrosine kinase inhibitors are of paramount importance. We present a case of ECD with multisystemic involvement, who was initially evaluated for the left lung mass and treated as tuberculosis, where fluorine-18-labeled fluorodeoxyglucose positron emission tomography/computed tomography aided in targeting the metabolically active site for biopsy as well as assessing the multisystemic involvement.

Precision Radiotherapy: 18F-FDG PET-based radiotherapy planning in Head and Neck cancers.

Precision medicine is gaining importance in this era of molecular imaging where the molecular features of a disease can be noninvasively assessed and treated with personalized medicine. This is especially suited for head and neck cancers (HNCa). Early stage HNCa are ideally managed with radiotherapy (RT) or surgery. Head and neck (HN) is a complex region and its tumors respond to RT differently due to dissimilar structures and moving organs such as tongue. Radiation oncologists are always in the process of trying and investigating newer RT techniques in order to achieve precise and targetted therapy to tumour/s. One such innovation is Intensity modulated RT (IMRT) using 3 Dimensional conformal RT (3DCRT). This 3DCRT resizes the radiation beams to match the shape of the tumor. Such focused dose escalation may improve local control in HNCa. Image guided RT in conjunction with IMRT is the most advanced form of RT planning being used these days. Simulation computerized tomography (CT) images are usually incorporated into RT planning module. But limitations of CT such as poor soft tissue contrast than magnetic resonance imaging and inability to clearly define solid / cystic / necrotic areas and viable tumour exist. Functional imaging such as Positron Emission Tomography (PET) has established its superiority over CT in delineating the actual site and extent of HN tumors. A combination of IMRT with BTV (Biological Tumour Volume) may be the most ideal technique to deliver a homogeneous radiation boost to tumour. This review shall discuss PET based RT planning, challenges, practical tips, and how to optimize therapy with the least side effects to the normal surrounding tissues.

Predictive value of sentinel lymph node imaging and biopsy in early cervical cancers: correlation with scintigraphic uptake patterns and histology.

AIM: This study was designed to 1) assess the feasibility, standardization of sentinel lymph node imaging (SLNI) and biopsy in early cervical cancers and also to determine the detection rates. 2) To analyze the SLN uptake pattern and correlate the findings with the histological grades of tumor. MATERIALS AND METHODS: 52 early cervical cancer patients underwent same-day Tc sulfur colloid (filtered) SLNI and biopsy with gamma probing. Patients underwent radical hysterectomy, para-aortic and pelvic lymphadenectomy irrespective of sentinel lymph node biopsy (SLNB) findings. We analyzed the colloid transit times, uptake pattern, lymphatic groups involved and histology. RESULTS: A total of 203 hot nodes (100% detection rate) were detected and harvested. Study showed 100% sensitivity, specificity, and negative predictive value. Internal iliac nodes were predominantly involved. Lymphatic uptake patterns were graded and correlated with tumor histology (Ki index). Transit time was relatively prolonged in patients with aggressive tumors. CONCLUSION: SLNI and biopsy in early cervical malignancies are feasible with high detection rate. Scintigraphic patterns of nodal uptake were relevant and found to correlate with the tumor histological grades. We found that nonfocal nodal uptake patterns were mainly encountered in patients with tumors having higher Ki index. Immunohistochemistry further facilitated identification of lymph nodal metastases. The visual grading system, implemented in this study provides a good indication of the degree of impairment of lymphatic drainage. Higher visual scintigraphic grade denotes greater lymphatic tumor burden.

Gamma Probe-Guided Surgery in Postoperative Recurrent Osteoid Osteoma of Left Index Finger.

Osteoid osteomas are painful benign osteoblastic tumors that usually affect the metaphysis or diaphysis of long bones. Hands are rarely involved. Identification of recurrent lesion by anatomical imaging modalities is a challenge especially in postoperative setting. Diagnosis of osteoid osteoma is based on typical clinical signs, radiographs, bone scintigraphy, thin-slice computed tomography, or magnetic resonance imaging. Atypical locations, multicentricity of nidus, or incomplete excision of the nidus result in a high rate of recurrence. Here we present a case of recurrent osteoid osteoma at an unusual site in left index finger and was operated under gamma probe guidance.

Does myocardial viability detection improve using a novel combined 99mTc sestamibi infusion and low dose dobutamine infusion in high risk ischemic cardiomyopathy patients?

OBJECTIVE: Early identification of viable myocardium in ischemic cardiomyopathy (ICM) patients is essential for early intervention and better clinical outcome. 99mTechnetium (99mTc) sestamibi gated myocardial perfusion imaging (gMPI) is a well-established technique for myocardial viability evaluation. Detection of potentially viable segments is a predictor of hibernating myocardium. ICM patients with hibernation have a better prognosis after revascularization. We used a novel infusion technique to determine better viability detection preoperatively in challenging situations. Like thallium, does prolonged availability of sestamibi in circulation with additional low dose dobutamine steady infusion (DS Inf) facilitate improved myocardial viability? METHODS: A total of 58 ICM patients with infarct and left ventricular ejection fraction (LVEF) <45% underwent 99mTc sestamibi bolus injection followed by slow intravenous infusion single-photon emission computed tomography (SPECT) using a 2 day protocol. After acquiring the second set of 99mTc sestamibi infusion images, a third SPECT gMPI was performed during DS Inf. RESULTS: A 17-segment myocardial model was used; 52 of 58 patients (548/986 segments) demonstrated perfusion defects (nonviable myocardium) on bolus study. Only 24 patients demonstrated viable segments by standard bolus imaging protocol. The slow MIBI infusion study demonstrated 158 viable segments (12 ICM patients), while combined infusion (99mTc sestamibi+DS Inf) exhibited an additional 6 patients with improved myocardial viability. Thus, 18 high risk patients benefited by this novel infusion technique to demonstrate viable myocardium on SPECT. There was a significantly higher sensitivity (p=0.05) and positive predictive value (p=0.01) in viability identification with the combined DS Inf technique. In dysfunctional segments, the rate of concordance for detecting viability between infusion and bolus techniques was 65%. Paired t test showed statistically significant improvement in viability detection with combined infusion compared to the bolus study (p=0.001). CONCLUSION: This novel infusion technique was shown to be feasible and incremental in viability detection in ICM patients with severe left ventricular dysfunction. It is a robust tool to guide revascularization, in high risk ICM patients. This study also showed that patients with large transmural MI demonstrated no significant improvement in myocardial perfusion status using either protocol.

Dual Thyroid Ectopia and Heterotopic Thyroid Autotransplantation.

Ectopic thyroid gland can be detected at any age. It is a developmental defect that results from abnormal migration of the primitive thyroid bud. Dual ectopia is very rare, and only a few cases have been reported in literature. Patients with thyroid ectopia may be either euthyroid or hypothyroid. Concept of thyroid autotransplantation is based on restoring euthyroidism and is an attempt to preserve the autoregulatory mechanism of hormone production. This is a case of dual ectopia who underwent heterotopic thyroid autotranplantation. Images demonstrate hypertrophy of the transplanted thyroid tissue with gradual restoration of thyroid trapping function.

Asymptomatic Large Pulmonary Arteriovenous Malformation Masquerading as a Metastatic Deposit in a Patient with Papillary Thyroid Carcinoma.

Adult cases of congenital arteriovenous malformation (AVM) of the mediastinum are extremely rare, and because of their varied clinical presentations, they pose a diagnostic challenge. There is no reported association of pulmonary AVM and papillary thyroid carcinoma. We describe a 38-year-old female with a large right lung AVM, multinodular goiter, and high serum thyroglobulin (Tg) with papillary thyroid carcinoma. The lung mass was believed to represent a pulmonary metastatic deposit due to high Tg value. Whole body I-131 scan and FDG PETMR imaging were performed as part of the workup.

Effectiveness of sentinel lymph node scintigraphy and intraoperative gamma probing with gold standard elective neck dissection in patients with N0 oral squamous cell cancers.

OBJECTIVE: Oral cancer ranks in the top three of all cancers in India, accounting for over 30% of all cancers reported. Elective neck dissection (END) is the mainstay of treatment in early disease. Performing ENDs for node negative (N0) patients can result in significant morbidity with questionable benefit and impair the patients' quality of life. Sentinel Lymph Node Biopsy (SLNB), is an emerging investigation helping in risk stratification of patients with early oral cancer and node negative disease. SLNB is a simple, easy to perform investigation with a high sensitivity and plays a major role in avoiding neck dissection. Studies have compared SLNB-based neck dissection with END in early oral cancers, and also on survival benefit with prophylactic neck dissection at the time of primary surgery as compared to watchful waiting followed by therapeutic neck dissection for nodal relapse, in patients with clinical N0 (cN0) oral squamous cell carcinoma (OSCC) on literature search. AIM: Our primary aim was to determine the effectiveness of lymphoscintigraphy in OSCC in clinically neck node negative (cN0) patients in comparison to gold standard END for nodal metastases identification and secondly to assess the utility of gamma probe in guiding SLNB in this group of patients. MATERIALS AND METHODS: Fifty-eight patients (M:F = 42:16) with histologically confirmed OSCC of T1-3 stage with cN0 and planned for curative intent primary surgical treatment were divided into two arms. All patients underwent sentinel lymph node (SLN) imaging and biopsy. Arm 1 underwent nodal dissection based on SLNB positivity, while all patients in arm 2 had wide neck dissection irrespective of SLNB findings. RESULTS: SLN was detected in all 58 patients, 96.4% patients showed SLN immediately postinjection. More than one SLN was found in 94.3% patients and 6.8% patients showed contralateral SLN also. Higher proportion of nodal metastasis were observed in tongue cancers than in remaining floor of mouth and buccal mucosa cancers (38% vs 12%, P< 0.01). We also found significant association between T size and nodal metastasis in our series. Sensitivity of SLNB was 88.23% with a specificity of 100%, both for SLN imaging and gamma probing localization reflecting the reliability of this technique. Serial step sectioning at 150 micrometre is recommended. SLNB showed positive nodes in 29.3 % patients with cN0 neck. We found that the association between the outcome in both arms was not statistically significant. On follow-up, three patients with T3N0 OSCC of arm 2 had nodal recurrence/lung metastases. One patient of arm 1 had nodal recurrence. Two patients expired within one year. As high as 73% patients (22 negative necks out of 30) had unwarranted neck dissection in arm 2. CONCLUSION: SLNB is an effective method to circumvent unwarranted neck dissection in early OSCC and prevent complications. Gamma probing is a robust and easy tool to identify SLN in T1-3 stages with N0 necks clinically. A positive SLNB is found to be reliable in guiding neck dissection in this small study. Larger studies are warranted to establish its recommendation in routine clinical practice.

Which is Better - A Standalone Ventilation or Perfusion Scan or Combined Imaging to Predict Postoperative FEV1 in One Seconds in Patients Posted for Lung Surgeries with Borderline Pulmonary Reserve.

INTRODUCTION: Forced expiratory volume in one second (FEV1) is an independent predictor for respiratory morbidity. Reports are varied and controversial substantiating the use of either lung perfusion (Q) or ventilation (V) scintigraphy as a single stage investigation to predict postoperative (ppo) FEV1 in patients scheduled for lung resection surgeries. It is said that there is no additional benefit by performing both V/Q scan. As per one of the recommendations, no further respiratory function tests are required for a lobectomy if the postbronchodilator FEV1 is >1.5 l. We wanted to study the ppo FEV1 in patients with FEV1 of <1.5 L scheduled for lung surgeries. Being a high-risk population, we wanted to assess (a) whether the ppo changes by this combined V/Q imaging and (b) whether the incidence of respiratory complication in the postoperative setting of this subgroup is different, (c) and study the short- and long-term clinical outcome. MATERIALS AND METHODS: Fifty-two high-risk patients (with comorbidities) and borderline preoperative FEV1 of 1.5 L or less planned for lung resection were enroled in this prospective study. V and Q scans were performed, and tracer uptake percentage was tabulated. RESULTS: Tracer uptake in each lung was quantitated. Manual method of ROI drawing is preferred in high risk patients with reduced pulmonary reserve over the automatic method. Based on uptake patterns by V/Q scans, 4 different types of patterns were tabulated. Eighty-eight percentage of centrally placed tumors showed the difference in uptake patterns. Chronic obstructive pulmonary disease patients usually showed more modest ventilatory defects (categorised as type 2 or 3). Lung tumours produce erratic uptake patterns (Type 4) which depend heavily on their location and extent. The range of FEV1 predicted was 0.6-1.38 L/min. CONCLUSION: We recommend that combined imaging should be performed in patients with borderline pulmonary reserve to derive the benefit of surgery as it provides a realistic ppo FEV1 in patients with moderate to severely damaged lung. Centrally placed hilar or bronchial tumors (even those <2 cm in size), produce discrepancies in V/Q distribution pattern. Patient who was thought ineligible for surgery due to low baseline FEV1 may be actually be operable by this combined imaging if uptake pattern is better in V or Q scan with a good outcome. Accurate estimation of postop FEV1 in fact helps the surgical team to implement measures to prepare high risk patients to reduce postoperative complications, enable faster weaning from ventilatory support and ensure favourable prognosis.

18F-FDG PET/CT in the evaluation of cancer cervix: Where do we stand today?

The incidence of gynecological malignancies is on the rise partly because of the availability of screening programmes, awareness, higher technological advancements, and availability of better medical care. Early diagnosis of any malignancy leads to prompt treatment. Use of 18Fluorine-Fluorodeoxyglucose (F-FDG) PET/CT in the treatment and follow-up of patients with Ca cervix considerably improves patient management. The primary diagnosis of Ca cervix is made either by biopsy of a visible tumor on the cervix or by a cone biopsy of a nonvisible malignant cervical focus. The staging procedure is purely clinical (i.e. gynecologic examination under general anesthesia) according to the International Federation of Gynaecology and Obstetrics classification. Earlier, with the nonavailability of sophisticated medical equipment and imaging specialists, oncologists relied heavily on clinical examination. However, anatomical and functional imaging has been proven to be considerably superior in understanding parametrial involvement and nodal/distant metastases in the cancer cervix than clinical examination alone. Data are evolving on the usage of F-FDG PET/CT in initial staging, treatment planning, and monitoring therapy response for gynecological malignancies. Prognostic information derived from the primary lesion such as the maximum standardized uptake value, metabolic tumor volume, and extent of para-aortic nodal metastatic disease plays a critical role in tailoring therapy on the basis of patient tumor-specific factors rather than on International Federation of Gynaecology and Obstetrics stage alone. Thus, F-FDG PET/CT needs to be listed not only under the panel of pretherapy investigations for Ca cervix but also for recurrence and therapy response assessments. It allows a more confident approach to patient management at initial staging, especially in terms of the decision to choose surgical versus palliation measures.