Edwaldo E. Camargo

18F-FDG PET/CT Delayed Images After Diuretic for Restaging Invasive Bladder Cancer

PET with 18F-FDG has been considered of limited value for detection of bladder cancer because of the urinary excretion of the tracer. The purpose of this study was to investigate the role of PET/CT in the detection and restaging of bladder cancer using furosemide and oral hydration to remove the excreted 18F-FDG from the bladder. Methods: Seventeen patients with bladder cancer (11 without cystectomy, 6 with total cystectomy and urinary diversion) underwent 18F-FDG PET/CT from head to the upper thighs 60 min after the intravenous injection of 370 MBq of 18F-FDG. Additional pelvic images were acquired 1 h after the intravenous injection of furosemide and oral hydration. PET/CT findings were confirmed by MRI, cystoscopy, or biopsy. Results: PET/CT was able to detect bladder lesions in 6 of 11 patients who had not undergone cystectomy. These images changed the PET/CT final reading in 7 patients: Recurrent bladder lesions were detected in 6 patients, pelvic lymph node metastases in 2 patients, and prostate metastasis in 1. This technique overcame the difficulties posed by the urinary excretion of 18F-FDG. Hypermetabolic lesions could be easily detected by PET and precisely localized in the bladder wall, pelvic lymph nodes, or prostate by CT. Seven of 17 patients (41%) were upstaged only after delayed pelvic images. Conclusion: Detection of locally recurrent or residual bladder tumors can be dramatically improved using 18F-FDG PET/CT with delayed images after a diuretic and oral hydration.

Cerebrospinal fluid flow abnormalities in patients with neoplastic meningitis: An evaluation using 111indium-DTPA ventriculography

Cerebrospinal fluid flow dynamics were evaluated by 111Indium-diethylenetriamine pentaacetic acid (111In-DTPA) ventriculography in 27 patients with neoplastic meningitis. Nineteen patients (70 percent) had evidence of cerebrospinal fluid flow disturbances. These occurred as ventricular outlet obstructions, abnormalities of flow in the spinal canal, or flow distrubances over the cortical convexities. Tumor histology, physical examination, cerebrospinal fluid analysis, myelograms, and computerized axial tomographic scans were not sufficient to predict cerebrospinal fluid flow patterns. These data indicate that cerebrospinal fluid flow abnormalities are common in patients with neoplastic meningitis and that 111In-DTPA cerebrospinal fluid flow imaging is useful in characterizing these abnormalities. This technique provides insight into the distribution of intraventricularly administered chemotherapy and may provide explanations for treatment failure and drug-induced neurotoxicity in patients with neoplastic meningitis.

Elevated thalamic and prefrontal regional cerebral blood flow in obsessive-compulsive disorder: a SPECT study

Functional neuroimaging studies have pointed to a possible role of cerebral circuits involving the prefrontal and anterior cingulate cortices, the striatum, and thalamus in the pathophysiology of obsessive-compulsive disorder (OCD). Regional cerebral blood flow (rCBF) of 16 drug-free Brazilian patients with OCD and 17 healthy subjects matched for age, gender, handedness and level of education was measured with [99m-Tc] HMPAO single photon emission computed tomography. Analysis of covariance identified four regions of interest with significantly higher rCBF: the right superior and inferior frontal cortex and the right and left thalamus. Positive correlations between symptom severity measured by Clinical Global Impression scores and rCBF were found in the right and left inferior frontal lobes and in the right basal ganglia. Compulsive behavior was inversely correlated with rCBF in the right thalamus, and duration of illness correlated positively with rCBF in the right and left superior frontal lobes and with the right thalamus. The findings of this SPECT study conducted in Brazil are in agreement with prior studies and provide additional support for the involvement of prefrontal-subcortical circuits in the pathophysiology of OCD. Furthermore, the study suggests that similar brain mechanisms appear to be involved cross-culturally.

Neuropsychological performance and regional cerebral blood flow in obsessive-compulsive disorder.

Convergent findings from neuropsychological and neuroimaging studies have suggested that neural dysfunction in frontal-subcortical circuits may play a central role in the pathophysiology of obsessive-compulsive disorder (OCD). To further examine the relationship between these two sets of findings we investigated both neuropsychological functions and regional cerebral blood flow (rCBF) in a combined study. Fourteen unmedicated patients fulfilling DSM-IV criteria for OCD and 14 healthy controls matched for age, gender, handedness, and education were assessed on neuropsychological tests that included Trail Making Test (TMT), Rey Complex Figure Test (RCF) (copy and 5-min recall), Verbal Fluency Test (VFT), and Wisconsin Card Sorting Test (WCST). rCBF was studied with 99 mTc-hexamethyl-propyleneamine-oxime (HMPAO) single photon emission computed tomography (SPECT). Patients performed more poorly than controls (P<.05) on RCF (copy), VFT, and WCST (perseverative errors). Spearmans correlations indicated that severity of OCD correlated inversely with performance on the RCF (copy and recall scores) and positively with rCBF in the right thalamus. Positive correlations were observed between nonperseverative errors (WCST) and rCBF in frontal areas and anterior cingulate. Perseverative errors (WCST) correlated negatively with rCBF in the right thalamus. These findings are consistent with most previously published studies and suggest neural dysfunctions in the frontal-subcortical circuits probably more pronounced in the right hemisphere. They also extend the existing research, showing associations between deficits in cortical-subcortical circuitry and performance on neuropsychological tests of controlled attention and visuospatial functions.

Gastric emptying and intragastric distribution of a solid meal in functional dyspepsia: Influence of gender and Anxiety

Background Gastric dysmotility and psychological factors have been implicated in the pathophysiology of functional dyspepsia. Goals To investigate the influence of gender and anxiety on gastric emptying and intragastric food distribution in patients with functional dyspepsia. Methods A standard gastric emptying test was used to study total and compartmental gastric emptying of a solid meal in 22 patients with functional dyspepsia (16 women). Comparisons of the data for dyspeptic men and women were made with 2 respective subgroups of controls (9 men; 9 women). The presence of anxiety and depression was assessed by the Hospital Anxiety and Depression scale. Results Delayed gastric emptying was observed in 32% of patients with functional dyspepsia. As a group, dyspeptic women had a significantly longer half-emptying time as compared with dyspeptic men (119 ± 41 min vs. 78 ± 22 min) and to female controls (96 ± 17 min). There was no difference in half-emptying times between male patients and controls. The initial activity in the proximal stomach was significantly lower for both men and women with functional dyspepsia in comparison with their respective controls. In addition, meal retention in the distal stomach of dyspeptic women was significantly greater than that in female controls. Sixteen (72%) functional dyspepsia patients had anxiety when evaluated by the Hospital Anxiety and Depression scale. Those patients who scored for anxiety showed significantly greater antral meal retention than patients without anxiety. Conclusion Our study confirmed that prolonged gastric emptying in patients with functional dyspepsia is related to the female sex, while the abnormalities of the meal intragastric distribution appear to occur in dyspeptic males and females. Anxiety is frequent in functional dyspepsia and seems to be related to abnormal antral retention of food in these patients.

Brain Single Photon Emission Computed Tomography Imaging in Landau-Kleffner Syndrome

Summary: Five right–handed children with Landau‐Kleffner syndrome (LKS) who had disease onset between the ages of 3 and 9 years were studied with EEG and single‐photon emission computed tomography (SPECT) before and, in four cases, after 6 months of corticosteroid treatment. EEG findings included both focal and generalized spikes as well as spike‐wave discharges with bilateral temporal predominance. These increased markedly during sleep in 1 child, and continuous spike‐and‐wave complexes appeared during slow‐wave sleep in another patient. Neuropsychological testing demonstrated verbal auditory agnosia. Magnetic resonance imaging (MRI) was performed in 4 children and was normal. Brain SPECT imaging demonstrated abnormal perfusion in the left temporal lobe in all patients. The response to corticosteroid therapy was mixed. Our findings reinforce the concept that LKS is a functional disease affecting the language‐dominant brain areas. We conclude that SPECT imaging may be of diagnostic assistance in the evaluation of this syndrome of unknown etiology.

68Ga-DOTATATE PET/CT, 99mTc-HYNIC-Octreotide SPECT/CT, and Whole-Body MR Imaging in Detection of Neuroendocrine Tumors: A Prospective Trial

There are different metabolic imaging methods, various tracers, and emerging anatomic modalities to stage neuroendocrine tumor (NET). We aimed to compare NET lesion detectability among 99mTc-hydrazinonicotinamide (HYNIC)-octreotide (somatostatin receptor scintigraphy [SSRS]) SPECT/CT, 68Ga-DOTATATE PET/CT, and whole-body diffusion-weighted MR imaging (WB DWI). Methods: Nineteen consecutive patients (34–77 y old; mean, 54.3 ± 10.4 y old; 10 men and 9 women) underwent SSRS SPECT/CT, 68Ga-DOTATATE PET/CT, and WB DWI. Images were acquired with a maximum interval of 3 mo between them and were analyzed with masking by separate teams. Planar whole-body imaging and SPECT/CT were performed from thorax to pelvis using a double-head 16-slice SPECT/CT scanner 4 h after injection of 111–185 MBq of 99mTc-HYNIC-octreotide. 68Ga-DOTATATE PET/CT was performed from head to feet using a 16-slice PET/CT scanner 45 min after injection of 185 MBq of tracer. WB DWI was performed in the coronal plane using a 1.5-T scanner and a body coil. The standard method of reference for evaluation of image performance was undertaken: consensus among investigators at the end of the study, clinical and imaging follow-up, and biopsy of suggestive lesions. Results: McNemar testing was applied to evaluate the detectability of lesions using 68Ga-DOTATATE PET/CT in comparison to SSRS SPECT/CT and WB DWI: a significant difference in detectability was noted for pancreas (P = 0.0455 and P = 0.0455, respectively), gastrointestinal tract (P = 0.0455 and P = 0.0455), and bones (P = 0.0082 and P = 0.0082). Two unknown primary lesions were identified solely by 68Ga-DOTATATE PET/CT. 68Ga-DOTATATE PET/CT, SSRS SPECT/CT, and WB DWI demonstrated, respectively, sensitivities of 0.96, 0.60, and 0.72; specificities of 0.97, 0.99, and 1.00; positive predictive values of 0.94, 0.96, and 1.00; negative predictive values of 0.98, 0.83, and 0.88; and accuracies of 0.97, 0.86, and 0.91. Conclusion: 68Ga PET/CT seems to be more sensitive for detection of well-differentiated NET lesions, especially for bone and unknown primary lesions. NET can be staged with 68Ga-DOTATATE PET/CT. WB DWI is an efficient new method with high accuracy and without ionizing radiation exposure. SSRS SPECT/CT should be used only when 68Ga-DOTATATE PET/CT and WB DWI are not available.

Predictive value of sentinel node biopsy in head and neck cancer

Conclusions. The negative predictive value (NPV) of sentinel lymph node biopsy (SNB) in this study was 95%. The accuracy of SNB compared to histopathologic evaluation of surgical specimen of subsequent neck dissection (ND) was 96%. Objective. To evaluate NPV of SNB in head and neck cancer. Patients and methods. This was a prospective clinical study comprising 35 patients (50 necks) with squamous cell carcinoma (SCC) of head and neck with clinically (cN0) and radiologically negative necks, without previous treatment, who underwent SNB with gamma probe and subsequent ND. The NPV, accuracy, sensitivity, and specificity of SNB were compared to histopathologic assessment of surgical specimens from NDs. Negative sentinel lymph nodes (SLNs) on histopathology were evaluated with step serial section (SSS) and immunohistochemistry (IHC). When a neck had a positive SLN, all lymph nodes of subsequent NDs were studied with SSS and IHC. Results. There were primaries of the oral cavity (n=24), lip (n=3), oropharynx (n=3), and larynx (n=5). All patients had detected SLNs. In all, 41 necks were SLN-negative on histopathologic evaluation but 2 (5%) had metastases in non-SLNs after ND. Of these 41 necks, SLNs were level Ib (26%), IIa (45%), III (21%), and IV (8%). Nine necks presented positive SLN on histopathologic evaluation, level Ib (n=3), IIa (n=5), and III (n=2), and subsequent NDs were negative on conventional histopathologic analysis, but after SSS and IHC, two presented micrometastases.

The Influence of Biological and Technical Factors on the Variability of Global and Regional Brain Metabolism of 2-[18F]Fluoro-2-Deoxy-D-Glucose:

This study investigated the influence of biological and technical factors on variations of global and regional cerebral metabolic rate of glucose (CMRglc) measured with 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG). Twelve male volunteers (22–40 years) were investigated on three or four occasions for a total of 42 studies. We calculated the variance/covariance of the following parameters: CMRglc, six parameters of the blood clearance of [18F]FDG, hour of injection, peak time of blood radioactivity, and six components of the operational equation (nonradioactive blood glucose concentration, brain radioactivity, two integrals, numerator, and denominator). There was correlation among these six components, except for nonradioactive blood glucose. However, the correlation between the CMRglc and the individual components of the operational equation was poor. The inter- and intrapersonal CMRglc coefficients of variations were 13.8 and 7.1%, respectively. In contrast, coefficients of variations of the numerator and denominator of the operational equation were 34.6 and 32.6%, respectively, and were always in the same direction. No correlation was found between CMRglc and the technical factors in the numerator and denominator of the operational equation. Factor analysis disclosed that a single factor was responsible for 70% of the variance. This factor included caudate, putamen, thalamus, frontal cortex, temporal cortex, and cingulate gyrus. These structures are involved with multiple complex functions, from autonomic motor control to behavior and emotions. The intrinsic metabolic variability of these structures, along with the basal metabolic processes that are continuously going on in the brain, may be the best explanation for the variance encountered in our investigation.

Fragile X syndrome: clinical, electroencephalographic and neuroimaging characteristics

We studied 11 patients (9 males) with cytogenetic diagnosis of fragile X syndrome (FXS) with the purpose of investigating the neural circuitry involved in this condition. The ages ranged from 8 to 19. All the individuals presented large ears, elongated faces and autistic features. Ten patients had severe mental retardation. Attention disorder was found in 10 individuals. Electroencephalographic recordings were abnormal in 6 of 10 patients examined, showing focal epileptiform discharges predominantly in frontal and parietal areas. All patients underwent magnetic resonance imaging studies which were abnormal in 8 of them. The most important abnormalities were reduction of the cerebellar vermis and enlargement of the IV ventricle. Single photon emission computerized tomography (SPECT) was performed in 7 patients and was abnormal in all of them, the most frequent finding being a hypoperfusion of the inferior of the frontal lobes. Based on the clinical picture, neuropsychological findings and functional and structural imaging studies we suggest that FXS presents with a dysfunction involving a large area of the central nervous system: cerebellum-basal frontal regions-parietal lobes. The literature points to a disturbance involving the same neural circuitry in patients with autism.