Statistical asymmetry analysis of volumetric MRI and FDG PET in temporal lobe epilepsy.

PURPOSE: To analyze statistically derived threshold values of volumetric MRI and 18F fluorodeoxyglucose (FDG) PET asymmetry, independent of normative data, for non-invasive detection/exclusion of temporal lobe epilepsy (TLE). METHODS: We retrospectively analyzed amygdalohippocampal volumetry and temporal FDG PET metabolism in 33 patients (age: 29.27 ±â€¯8.56 years) who underwent surgery following Stereo-EEG implantation and had postsurgical seizure freedom lasting >12 months. The temporal lobe epilepsy group and the extratemporal lobe epilepsy (ETLE) group were compared. Percentage volume loss (PVL) was calculated from manually traced amygdalohippocampal volumetry whereas percentage metabolic loss (PML) was calculated from PET using amygdalohippocampal trace and temporal neocortical Brodmann areas (BA) template. RESULTS: Receiver operating characteristic (ROC) curve analysis identified a cutoff hippocampal PVL of 4.21% as the minimum indicating probable hippocampal involvement in seizure onset, with sensitivity of 88.89% and the specificity of 100% (p < 0.001). Region of interest (ROI)-based PML values in PET imaging showed a significant correlation with the presence of TLE in the TLE group of patients and its absence in the ETLE group of patients. Region of interest curve analysis yielded PML cutoffs of 5.77% and 8.36%, respectively, for the hippocampus and BA 38 (temporopolar neocortex) to detect TLE with the sensitivity of 72.7% and specificity of 77.8%. CONCLUSION: We describe statistical thresholds for asymmetry analysis of hippocampal volumetry and FDG PET to improve detection of TLE. These threshold parameters warrant further validation in prospective studies.

Comparison of whole-body bone scintigraphy with axial skeleton magnetic resonance imaging in the skeletal evaluation of carcinoma prostate.

INTRODUCTION: Whole-body bone scintigraphy (WBBS) is considered to be the standard of care in the initial skeletal evaluation of patients with carcinoma prostate. Magnetic resonance imaging (MRI) is a potential alternative technique for detecting bone metastasis. The objective of this study was to compare the diagnostic performance of WBBS with a single-photon emission computed tomography-computed tomography (SPECT-CT) correlation of the suspicious WBBS lesions to the axial skeleton (AS)-MRI in diagnosing bone metastasis in patients with carcinoma prostate. METHODS: WBBS and AS-MRI were both performed during the initial skeletal evaluation in 35 patients of carcinoma prostate with the prostate-specific antigen (PSA) in the range of 10-50 ng/ml. Suspicious lesions on the WBBS were correlated on SPECT CT. The presence or absence of metastasis was determined by best valuable comparator. The validity parameters of WBBS and AS-MRI were computed and compared. RESULTS: The sensitivity, specificity, positive predictive value, and negative predictive value of WBBS and AS-MRI for detecting patients with bone metastasis were 55.6%, 88.5%, 62.5%, 85.2% and 100.0%, 96.2%, 90.0%, 100%, respectively. The kappa value and the accuracy of WBBS were 0.457 and 80.0%, respectively. The kappa value and accuracy of AS-MRI were 0.928 and 97.1%, respectively. CONCLUSIONS: The diagnostic performance of AS-MRI in detecting patients with bone metastasis due to carcinoma prostate is superior to that of WBBS with SPECT-CT correlation of the suspicious lesions in the PSA range of 10-50 ng/ml.

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 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.

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.

Synchronous Bilateral Multifocal Warthin's Tumor Mimicking Primary Malignancy on 18 F-FDG Whole Body PET/CT in a Case of Metastatic Cervical Lymph Nodes from Unknown Primary Malignancy.

Warthin's tumor is a benign and frequently encountered salivary gland neoplasm. Bilaterality and multifocality are rare in Warthin's tumor. Synchronous cervical lymph nodal metastasis with unknown primary in a case of Warthin's tumor can raise a suspicion of primary malignancy of the parotid gland. We present a case of bilateral multifocal Warthin's tumor with synchronous squamous cell carcinoma metastasis to the cervical lymph node. 18 F-fluorodeoxyglucose whole body positron emission tomography/computed tomography imaging showed hypermetabolic bilateral multifocal parotid lesions and metastatic cervical lymph node with unknown primary malignancy.

Asymmetry index in anatomically symmetrized FDG-PET for improved epileptogenic focus detection in pharmacoresistant epilepsy.

OBJECTIVE: Positron emission tomography (PET) imaging has assumed an essential role in the presurgical evaluation of epileptogenic foci in drug-resistant epilepsy by identifying the hypometabolic cerebral cortex. The authors herein designed a pilot study to test a novel technique of PET asymmetry after anatomical symmetrization coregistered to MRI (PASCOM), utilizing interhemispheric metabolic asymmetry on interictal fluorine 18-labeled fluorodeoxyglucose (FDG)-PET to better localize the epileptogenic zone. METHODS: The authors analyzed interictal FDG-PET scans from 23 patients with drug-resistant epilepsy, mean (± SD) age 20.9 ± 13.1 years old, who had an Engel class I postsurgical outcome while followed up for > 12 months. T1-weighted and FLAIR MRI were used to create a patient-specific, structurally symmetrical template. The asymmetry index (AI) image was computed to detect the cerebral region of hypometabolism using different z-score threshold criteria to optimize sensitivity and specificity. The detected regions were compared with the resection cavity on postoperative MRI using predefined anatomical labels. PASCOM was compared with the visual analysis of FDG-PET by a nuclear medicine consultant blinded to other clinical data (VIS) and visual analysis during multidisciplinary team discussion (MDT). The efficacy of each technique was compared based on a performance score (S), sensitivity, specificity, and correct lateralization of epileptogenicity. RESULTS: The mean S was maximum (1.30 ± 1.23) for AI images when thresholded at z > 4 and retaining the cluster of more than 100 voxels containing the peak AI value (Z4C) with 73.03% sensitivity and 96.43% specificity. The mean S was minimum for VIS (0.27 ± 0.31). The mean sensitivity was maximum for MDT (85.04%) and minimum for Z5C (AI images thresholded at z > 5 and clustered; 59.47%), whereas the mean specificity was maximum for Z5C (97.77%) and minimum for VIS (64.60%). Z3C (AI images thresholded at z > 3 and clustered) and Z4C were able to correctly identify the side of epileptogenicity in all the patients. CONCLUSIONS: The PASCOM technique with a Z4C threshold had a maximum performance score with good sensitivity and specificity in localizing and lateralizing the epileptogenic zone. The described technique outperformed the conventional visual analysis of FDG-PET and hence warrants further prospective verification.

68Ga-DOTANOC PET/CT in Multiple Endocrine Neoplasia 1 With Associated Adrenocortical Carcinoma.

ABSTRACT: Multiple endocrine neoplasia 1 (MEN1) syndrome is an autosomal dominant syndrome comprising a triad of pancreatic, pituitary, and parathyroid tumors. Adrenal cortical carcinoma occurs rarely in MEN1 syndrome. Here, we have presented a case of a 62-year-old woman with adrenal mass and elevated serum parathormone levels, who underwent 68Ga-DOTANOC PET/CT. 68Ga-DOTANOC PET/CT showed intense tracer concentration in the left adrenal mass and lesions in the liver, pancreas, and peritoneum. Biopsy of the peritoneal deposit revealed metastatic adrenocortical carcinoma, and further genetic testing showed MEN1 mutation.

Extrahepatic metastases of hepatocellular carcinoma on 18F FDG PET CT.

BACKGROUND: To determine locations, relative frequencies, imaging features, and pattern of distribution of extrahepatic metastasis from hepatocellular carcinoma (HCC) on 2-deoxy-2-[fluorine-18]fluoro-D-glucose (18F-FDG) PET CT. METHODS: FDG PET CT scans of 224 consecutive patients of HCC acquired between 2010 and 2018 were reviewed. Fifty-six patients detected with extrahepatic metastasis on FDG PET CT were retrospectively analyzed. Findings were correlated with prior/follow-up imaging studies, clinical findings, FNAC, or biopsy findings whenever available. Descriptive analysis of location, relative frequencies, imaging features, and pattern of distribution of extrahepatic metastasis was done. RESULTS: Commonest were metastatic pulmonary nodules (55.3% patients), most of them being well-defined solid lesions (53.5%) with bilateral involvement in 44.6% patients and lower lobes of lungs along with other lobes being more frequently involved (41.0% patients). While in 7.14% patients lung nodules were FDG avid, 23.2% patients had both FDG avid and non-avid pulmonary nodules. Second most common were regional metastatic lymph nodes in 44.65% of patients seen at aortocaval (25%), paraaortic (23.21%), portocaval (21.4%), and left gastric nodal (17.8% of patients) stations. Twenty-five percent of patients had FDG avid lymph nodes and 5.36% patients had both FDG avid and FDG non-avid lymph nodes. Distant metastatic lymph nodes were third most common in 39.2% of patients seen at paratracheal (2.5%), juxtaphrenic (8.9%), and mesenteric lymphnodal (7.1%) stations. Twenty-five percent of patients had FDG avid lymph nodes while 5.36% patients had both FDG avid and FDG non-avid lymph nodes. Skeletal involvement was seen in 32.1% of patients. Commonest sites are vertebrae (16.7%), pelvis (14.2%), and ribs (10.7% patients). Six out of 7 patients had unilateral adrenal gland involvement. Bilateral adrenal gland involvement was seen in 1 patient. FDG non-avid peritoneal/omental metastases was seen in 2 patients. Brain, spleen, and muscle metastatic lesions were seen in 1 patient each out of 56 patients (1.79%). CONCLUSIONS: Lungs, regional and distant lymph nodes and skeleton are the most frequently involved sites of extrahepatic metastatic hepatocellular carcinoma. Adrenal glands, muscles, brain and peritoneum are also involved but to a lesser extent.

Seizure outcome following primary motor cortex-sparing resective surgery for perirolandic focal cortical dysplasia.

OBJECTIVES: We present a case series of patients who underwent perirolandic resection for medically refractory focal epilepsy due to focal cortical dysplasia (FCD). Our aim was to specifically evaluate the outcome of a surgical strategy intended for seizure freedom while preserving primary motor cortex function. MATERIALS AND METHODS: Thirteen patients undergoing perirolandic resection for pharmacoresistant focal epilepsy between 2010 and 2015 who demonstrated histological evidence of FCD were selected from a prospectively maintained database. Presurgical evaluation included video EEG telemetry and 3T MRI brain for all patients. Eight patients underwent interictal FDG PET scan. Intracranial EEG monitoring was done for 8 patients - six by conventional subdural grid and depth electrodes and two by Stereo EEG. Additional techniques included extraoperative cortical stimulation mapping, intraoperative electrocorticography (ECoG), intraoperative motor cortex mapping and awake surgery in various combinations. In all cases (lesional and nonlesional), resection was intentionally limited for anatomic preservation of the primary motor cortex. RESULTS: Amongst the thirteen patients with age ranging 14-44 years (mean 26.8 ± 9.2) 62% of them had daily seizures. MRI abnormalities were identified in 8 patients (62%), PET showed concordant findings in 7 patients (88%). When utilized, the mean duration of intracranial EEG recordings was 8.0 ± 7.2 days (range 2-23 days). All patients underwent a primary motor cortex-sparing resection of the suspected epileptogenic cortex. The mean postoperative follow up period was 23 months (range 7.5-62 months). Twelve out of 13 (92%) were seizure free (Engel 1) outcome at the last follow-up assessment; one patient had Engel 2a outcome at 28 months. Six patients (46%) had immediate new focal neurological deficits, however all six patients had recovered completely within three months. CONCLUSION: The surgical strategy of a primary motor cortex-sparing resective surgery for perirolandic FCD is associated with an excellent early seizure-freedom rate and no permanent neurological deficits. Since the ultimate goal of resective epilepsy surgery is seizure freedom with simultaneous functional preservation, similar long term outcome studies should ultimately guide the resection strategy.

Isolated skeletal muscle metastatic deposit in a patient with micropapillary carcinoma thyroid identified by 18F FDG PET CT.

Micropapillary carcinoma of thyroid is said to be low risk differentiated thyroid malignancy with excellent prognosis. We report the identification of an isolated FDG avid muscle deposit in a treated case of micropapillary carcinoma of the right lobe and widely invasive follicular carcinoma of the left lobe thyroid gland. Patient was found to have an elevated thyroglobulin level with negative iodine scan (TENIS syndrome) on follow up at 6 months. An 18F FDG PET CT (18 fluorine-fluorodeoxyglucose positron emission computed tomography) whole body study revealed a solitary FDG avid deltoid muscle deposit which was histopathologically confirmed to be metastatic papillary carcinoma. While follicular carcinoma is known to have distant metastases, this may be the first reported case of solitary skeletal metastases from micropapillary carcinoma of thyroid and probably the second reported skeletal muscle deposit from DTC detected on 18F FDG PET CT done following elevated thyroglobulin level and negative 131 iodine WB scan (TENIS). This case also assumes importance because it demonstrates possibility of metastases even from a micropapillary carcinoma in contrast to American Thyroid Association guidelines (2009) which suggests that micropapillary carcinoma of thyroid does not merit further treatment after a Total Thyroidectomy.

18-F flourodeoxy glucose positron emission tomography-computed tomography imaging: A viable alternative to three phase bone scan in evaluating diabetic foot complications?

BACKGROUND: This paper is based on the initial findings from a prospective ongoing study to evaluate the efficacy of flourodeoxy glucose positron emission tomography-computed tomography (FDG-PET CT) in diabetic foot evaluation. OBJECTIVE: The aim was to compare the diagnostic accuracies of three phase bone scan (TPBS) and FDG PET-CT (FDG-PET) in diabetic foot evaluation. METHODS: Seventy-nine patients with complicated diabetic foot (osteomyelitis/cellulitis, Charcot's neuropathy) were prospectively investigated. TPBS (15 mci methylene di phosphonate [MDP] intravenous [IV]), followed by FDG-PET (5 mci IV) within 5 days were performed in all patients. Based on referral indication, patients grouped into Group I, n = 36, (?osteomyelitis/cellulitis) and Group II, n = 43 (?Charcot's neuropathy). Interpretation was based on intensity, extent, pattern of MDP and FDG uptake (standardized uptake value) along with CT correlation. Findings were compared with final diagnostic outcome based on bone/soft tissue culture in Group I and clinical, radiological or scintigraphic followup in Group II. RESULTS: Group I: For diagnosing osteomyelitis, TP: TN: FP: FN were 14:5:2:2 by FDG PET and 13:02:05:03 by TPBS respectively. Sensitivity, specificity, positive predictive value and negative predictive value (NPV) of FDG-PET were 87.5%, 71%, 87.5% and 71% and 81.25%, 28.5%, 72% and 40% for TPBS, respectively. Group II: charcot's: cellulitis: Normal were 22:14:7 by FDG PET and 32:5:6 by TPBS, respectively. CONCLUSION: Flourodeoxy glucose PET-CT has a higher specificity and NPV than TPBS in diagnosing pedal osteomyelitis. TPBS, being highly sensitive is more useful than FDG-PET in detecting Charcot's neuropathy.

Random synchronous malignancy in male breast: a case report.

We report here a case of a random synchronous male breast malignancy in a patient with a known base of tongue malignancy that was incidentally detected on a whole body 18-fluorine deoxyglucose positron emission tomography and computed tomography ((18)F-FDG PET/CT). Patient was referred to us for PET/CT staging and radiotherapy planning for a poorly differentiated squamous cell carcinoma of base of tongue. Histopathologically, the incidentally detected breast lesion was proven to be an invasive ductal carcinoma. (18)F-FDG PET/CT being a whole body imaging modality is known to detect a considerable number of synchronous primaries. Synchronous malignancies in the head and neck area and the upper aerodigestive tract are well established. However, synchronous malignancy in male breast is reportedly uncommon. Our case is unique for the fact that a random synchronous dual malignancy of base of tongue and breast in a male patient was detected during a whole body (18)F-FDG PET/CT imaging.

Potential of (18)F-FDG-PET as a valuable adjunct to clinical and response assessment in rheumatoid arthritis and seronegative spondyloarthropathies.

AIM: To evaluate the role of fluorine-18-labeled fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) in various rheumatic diseases and its potential in the early assessment of treatment response in a limited number of patients. METHODS: This study involved 28 newly diagnosed patients, of these 17 had rheumatoid arthritis (RA) and 11 had seronegative spondyloarthropathy (SSA). In the SSA group, 7 patients had ankylosing spondylitis, 3 had psoriatic arthritis, and one had non-specific SSA. Patients with RA were selected as per the American College of Rheumatology criteria. One hour after FDG injection, a whole body PET scan was performed from the skull vertex to below the knee joints using a GE Advance dedicated PET scanner. Separate scans were acquired for both upper and lower limbs. Post-treatment scans were performed in 9 patients in the RA group (at 6-9 wk from baseline) and in 1 patient with psoriatic arthropathy. The pattern of FDG uptake was analysed visually and quantified as maximum standardized uptake value (SUVmax) in a standard region of interest. Metabolic response on the scan was assessed qualitatively and quantitatively and was correlated with clinical assessment. RESULTS: The qualitative FDG uptake was in agreement with the clinically involved joints, erythrocyte sedimentation rate, C-reactive protein values and the clinical assessment by the rheumatologist. All 17 patients in the RA group showed the highest FDG avidity in painful/swollen/tender joints. The uptake pattern was homogeneous, intense and poly-articular in distribution. Hypermetabolism in the regional nodes (axillary nodes in the case of upper limb joint involvement and inguinal nodes in lower limb joints) was a constant feature in patients with RA. Multiple other extra-articular lesions were also observed including thyroid glands (in associated thyroiditis) and in the subcutaneous nodules. Treatment response was better appreciated using SUVmax values than visual interpretation, when compared with clinical evaluation. Four patients showed a favourable response, while 3 had stable disease and 2 showed disease progression. The resolution of regional nodal uptake (axillary or inguinal nodes based on site of joint involvement) in RA following disease modifying anti-rheumatoid drugs was noteworthy, which could be regarded as an additional parameter for identifying responding patients. In the SSA group, uptake in the affected joint was heterogeneous, low grade and non-symmetrical. In particular, there was intense tendon and muscular uptake corresponding to symptomatic joints. The patients with psoriatic arthritis showed intense FDG uptake in the joints and soft tissue. CONCLUSION: (18)F-FDG PET accurately delineates the ongoing inflammatory activity in various rheumatic diseases (both at articular and extra-articular sites) and relates well to clinical symptoms. Different metabolic patterns on FDG-PET scanning in RA and SSA can have important implications for their diagnosis and management in the future with the support of larger studies. FDG-PET molecular imaging is also a sensitive tool in the early assessment of treatment response, especially when using quantitative information. With these benefits, FDG-PET could play a pivotal clinical role in the management of inflammatory joint disorders in the future.