Francesco Mungai

Interaction of caudate dopamine depletion and brain metabolic changes with cognitive dysfunction in early Parkinson's disease

Damage to nonmotor dopamine (DA)-mediated frontostriatal circuits has been proposed as the main pathophysiological basis of cognitive dysfunction in Parkinsons disease (PD). In the present study, 18 early nondemented drug naive PD patients were investigated, by dual-tracer N-ω-fluoropropyl-2β-carbomethoxy-3β-4-[123I]iodophenyl-nortropane ([123I]FP-CIT) single-photon emission computed tomography (SPECT)/[18F] fluoro-deoxyglucose (FDG) positron emission tomography (PET) imaging, to test whether an early and not yet treatment-modulated relation exists between cognitive functions, caudate nucleus (CN) DA impairment and brain metabolism (CMRglc) in associative frontostriatal circuits. Verbal fluency performance correlated with DA impairment in CN, and with CMRglc in dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC). Further, CMRglc in orbitofrontal cortex, DLPFC, and ACC was shown to be early modulated by the level of DA impairment in CN. The present study demonstrates in vivo the early functional disruption of nonmotor frontostriatal circuits in PD. The effect of CN DA impairment on DLPFC and ACC metabolism is proposed as a possible early pathophysiological and functional substrate for executive dysfunction in PD.

Brain metabolic correlates of dopaminergic degeneration in de novo idiopathic Parkinson’s disease

PurposeThe aim of the present study was to evaluate the reciprocal relationships between motor impairment, dopaminergic dysfunction, and cerebral metabolism (rCMRglc) in de novo Parkinson’s disease (PD) patients.MethodsTwenty-six de novo untreated PD patients were scanned with 123I-FP-CIT SPECT and 18F-FDG PET. The dopaminergic impairment was measured with putaminal 123I-FP-CIT binding potential (BP), estimated with two different techniques: an iterative reconstruction algorithm (BPOSEM) and the least-squares (LS) method (BPLS). Statistical parametric mapping (SPM) multiple regression analyses were performed to determine the specific brain regions in which UPDRS III scores and putaminal BP values correlated with rCMRglc.ResultsThe SPM results showed a negative correlation between UPDRS III and rCMRglc in premotor cortex, and a positive correlation between BPOSEM and rCMRglc in premotor and dorsolateral prefrontal cortex, not surviving at multiple comparison correction. Instead, there was a positive significant correlation between putaminal BPLS and rCMRglc in premotor, dorsolateral prefrontal, anterior prefrontal, and orbitofrontal cortex (p < 0.05, corrected for multiple comparison).ConclusionsPutaminal BPLS is an efficient parameter for exploring the correlations between PD severity and rCMRglc cortical changes. The correlation between dopaminergic degeneration and rCMRglc in several prefrontal regions likely represents the cortical functional correlate of the dysfunction in the motor basal ganglia-cortical circuit in PD. This finding suggests focusing on the metabolic course of these areas to follow PD progression and to analyze treatment effects.

Diagnostic imaging to detect and evaluate response to therapy in bone metastases from prostate cancer: current modalities and new horizons

Different therapeutic options for the management of prostate cancer (PC) have been developed, and some are successful in providing crucial improvement in both survival and quality of life, especially in patients with metastatic castration-resistant PC. In this scenario, diverse combinations of radiopharmaceuticals (for targeting bone, cancer cells and receptors) and nuclear medicine modalities (e.g. bone scan, SPECT, SPECT/CT, PET and PET/CT) are now available for imaging bone metastases. Some radiopharmaceuticals are approved, currently available and used in the routine clinical setting, while others are not registered and are still under evaluation, and should therefore be considered experimental. On the other hand, radiologists have other tools, in addition to CT, that can better visualize bone localization and medullary involvement, such as multimodal MRI. In this review, the authors provide an overview of current management of advanced PC and discuss the choice of diagnostic modality for the detection of metastatic skeletal lesions in different phases of the disease. In addition to detection of bone metastases, the evaluation of response to therapy is another critical issue, since it remains one of the most important open questions that a multidisciplinary team faces when optimizing the management of PC. The authors emphasize the role of nuclear modalities that can presently be used in clinical practice, and also look at future perspectives based on relevant clinical data with novel radiopharmaceuticals.

Clinical correlation of the binding potential with 123I-FP-CIT in de novo idiopathic Parkinson’s disease patients

PurposeThe aim of this study was to evaluate the accuracy of different single-photon emission computed tomography (SPECT) reconstruction techniques in measuring striatal N-ω-fluoropropyl-2β-carbomethoxy-3β-4-[123I]iodophenyl-nortropane (123I-FP-CIT) binding in de novo Parkinson’s disease (PD) patients, in order to find a correlation with clinical scales of disease severity in the initial phases of disease.MethodsThirty-six de novo PD patients underwent 123I-FP-CIT SPECT and MRI scan. SPECT data were reconstructed with filtered back projection (FBP), with an iterative algorithm (ordered subset expected maximization, OSEM) and with a method previously developed in our institution, called least-squares (LS) method. The ratio of specific to non-specific striatal 123I-FP-CIT binding (binding potential, BP) was used as the outcome measure with all the reconstruction methods (BPFBP, BPOSEM, BPLS).ResultsThe range of values of striatal BPLS was significantly greater than BPFBP and BPOSEM. For all striatal regions, estimates of BPFBP correlated well with BPOSEM (r = 0.84) and with BPLS (r = 0.64); BPOSEM correlated significantly with BPLS (r = 0.76). A good correlation was found between putaminal BPLS and Hoen and Yahr, Unified PD Rating Scale (UPDRS) and lateralized UPDRS motor scores (r = −0.46, r = −0.42, r = −0.39, respectively). Neither putaminal BPFBP nor putaminal BPOSEM correlated with any of these motor scores.ConclusionsIn de novo PD patients, 123I-FP-CIT BP values derived from FBP and OSEM reconstruction techniques do not permit to differentiate PD severity. The LS method instead finds a correlation between striatal BP and disease severity scores. The results of this study support the use of 123I-FP-CIT BP values estimated with the LS method as a biomarker of PD severity.

Bile leak after elective laparoscopic cholecystectomy: Role of MR imaging

Increasing hepatobiliary laparoscopic surgeries have lead to a rise in injury to the biliary tree and other complications like bile leak. Ultrasonography (US) and computed tomography (CT) cannot reliably distinguish bile from other postoperative fluid collections. Magnetic resonance (MR) imaging with hepatobiliary agents and MR cholangiopancreatography provide anatomic and functional information that allows for prompt diagnosis and excludes any other concomitant complications. We report a case of post-cholecystectomy bile leak in a 42-year-old female who presented with persistent dull abdominal pain after the intervention; we emphasize the role of MR imaging in achieving the correct diagnosis.

Focal liver lesion classification and characterization in noncirrhotic liver: a prospective comparison of diffusion-weighted magnetic resonance-related parameters.

Purpose The objective of this study was to prospectively verify if diffusion-weighted magnetic resonance (DwMR)–related parameters such as perfusion fraction (f) and slow diffusion coefficient (D), according to Le Bihan theory, are more effective than apparent diffusion coefficient (ADC) for classification and characterization of the more frequent focal liver lesions (FLLs) in noncirrhotic liver. Methods Sixty-seven patients underwent standard liver magnetic resonance imaging (MRI) and free-breath multi-b DwMR study. Two regions of interest were defined by 2 observers, including 1 FLL for each patient (21 hemangiomas, 21 focal nodular hyperplasias, 25 metastases) and part of surrounding parenchyma, respectively. For every FLL, D, f, and ADC were estimated both as absolute value and as ratio between FLL and surrounding parenchyma by fitting the reduced equation of the bicompartmental model to experimental data; t test, analysis of variance, and receiver operating characteristic analysis were performed. Results t Test showed significant differences in ADClesion, f lesion, D lesion, ADCratio, and D ratio values between benign and malignant FLLs, more pronounced for ADClesion (P < 0.0009) and ADCratio (P = 0.001). Applying cutoff values of 1.55 × 10 − 3 mm2/s (ADClesion) and 0.89 (ADCratio), the DwMR study presented sensitivities and specificities, respectively, of 84% and 80% (for ADClesion), 72% and 80% (ADCratio). Conclusions Apparent diffusion coefficient (by fitting procedures) better performs than do D and f in FLL classification, especially when its values are less than 1.30 or greater than 2.00 × 10 − 3 mm2/s.

CT colonography before colonoscopy in subjects with positive faecal occult blood test. Preliminary experience.

PurposeWe report a preliminary evaluation of the performance of computed tomography colonography (CTC) systematically obtained before optical colonoscopy (OC) in subjects with positive faecal occult blood test (FOBT) within a population-based screening programme for colorectal cancer (CRC).Materials and methodsSeventy-nine subjects with positive FOBT from a regional screening programme were invited to perform same day CTC and OC. CTC was performed with standard bowel preparation. OC with segmental unblinding was the reference standard. A perpatient per-adenoma analysis was performed.ResultsForty-nine of 79 subjects (62%) with positive FOBT adhered to the study and completed both examinations. Twenty-two (44.9%) of the 49 had a cancer or an adenoma ≥6 mm. Per-patient sensitivity, specificity, negative predictive value and positive predictive value for cancer or adenoma ≥6 mm were 95.5% (95%CI:77.2%–99.9%), 51.9% (95%CI:32.0%–71.3%), 93.3% (95%CI:68.1%–99.8%) and 61.8% (95%CI:43.6%–77.8%).ConclusionsIn the setting of a FOBT-based screening programme for CRC, CTC showed a high sensitivity, but relatively low specificity and positive predictive value, for cancer and adenoma ≥6 mm. Probably performing CTC without faecal tagging as second line test after a positive FOBT is not a cost-effective strategy.RiassuntoObiettivoValutare la performance della colongrafia TC (CTC) eseguita sistematicamente prima della colonscopia ottica (CO) in soggetti con test del sangue occulto fecale (FOBT) positivo nell’ambito di un programma di screening di popolazione per il cancro colorettale.Materiali e metodiSettantanove soggetti FOBT positivi del programma di screening della regione Toscana sono stati invitati ad eseguire nello stesso giorno la CTC e la CO dopo preparazione intestinale standard (polietilenglicole). Come standard di riferimento è stata utilizzata la CO effettuata con la tecnica del “segmental unblinding”. Sono stati calcolati i valori di sensibilità, specificità, valore predittivo negativo (VPN) e positivo (VPP) per-paziente per-adenoma.RisultatiSu 79 soggetti invitati 49 (62%) hanno accettato di partecipare allo studio. Ventidue soggetti (44,9%) su 49 hanno presentato un cancro o un adenoma ≥6 mm. I valori di sensibilità, specificità, VPN e VPP per-paziente nella detezione di cancri o adenomi ≥6 mm sono risultati rispettivamente del 95,5% (95%CI:77,2%‐99,9%), 51,9% (95%CI:32,0%–71,3%), 93,3% (95%CI:68,1%–99,8%) e del 61,8% (95%CI:43,6%–77,8%).ConclusioniNel contesto di un programma di screening basato sul FOBT, la CTC ha mostrato elevata sensibilità ma bassi valori di specificità e valore predittivo positivo. Probabilmente utilizzare la CTC come test di secondo livello nei soggetti FOBT positivi non è una strategia costo-efficace.

Diffusion Weighted MR and Apparent Diffusion Coefficient Measurement in Classification and Characterization of Noncystic Focal Liver Lesions: Does a Clinical Role Exist?

AbstractThe objective of this study was to assess the clinical role of apparent diffusion coefficient (ADC) analysis in noncystic focal liver lesion (FLL) classification/characterization.Six hundred liver magnetic resonances with multi-b (b = 50, 400, 800 s/mm2) diffusion-weighted imaging (DwI) were retrospectively reviewed. Mean ADC was measured in 388 lesions (195 benign and 193 malignant) excluding internal necrotic areas. Cystic benign lesions were excluded from analysis. Sensitivity and specificity in distinguishing benign from malignant lesions were calculated. Analysis of variance was performed to detect differences among subgroups of solid lesions.Mean ADC of malignant lesions was 0.980 × 10−3 mm2/s, significantly (P < 0.05) lower than mean ADC of benign lesions (1.433 × 10−3 mm2/s). Applying an ADC cutoff of 1.066 × 10−3 mm2/s, specificity and sensitivity for malignancy were respectively 86.6% and 73.6%. Of all lesions, >1/3 (39.5%) presented values lower than 1 × 10−3 mm2/s, with 90.0% chance of malignancy. Above 1.5 × 10−3 mm2/s (about 20% of all lesions) chance of malignancy was 9.5%.DwI cannot assist in noncystic FLL characterization, but can help in FLL classification in about half the cases.

Is Panoramic Radiography an Accurate Imaging Technique for the Detection of Endodontically Treated Asymptomatic Apical Periodontitis

Introduction This study aimed to evaluate the diagnostic accuracy of panoramic radiography (PAN) for the detection of clinically/surgically confirmed apical periodontitis (AP) in root canal–treated teeth using cone‐beam computed tomographic (CBCT) imaging as the reference standard. Methods Two hundred forty patients with endodontically treated AP (diseased group) were detected via CBCT imaging using the periapical index system. They were divided into groups of 20 each according to lesion size (2–4.5 mm and 4.6–7 mm) and anatomic area (incisor, canine/premolar, and molar) in both the upper and lower arches. Another 240 patients with root filling and a healthy periapex (healthy group) were selected. All diseased and healthy patients underwent PAN first and a CBCT scan within 40 days. The periapical index system was also used to assess AP using PAN. Sensitivity, specificity, diagnostic accuracy, positive predictive value, and negative predictive value for PAN images with respect to CBCT imaging were analyzed. The k value was calculated to assess both the interobserver reliability for PAN and the agreement between PAN and CBCT. Results PAN showed low sensitivity (48.8), mediocre negative predictive value (64.7), good diagnostic accuracy (71.3), and high positive predictive value (88.6) and specificity (93.8). Both interobserver reliability for PAN and agreement between PAN and CBCT were moderate (k = 0.58 and 0.42, respectively). The best identified AP was located in the lower canine/premolar and molar areas, whereas the worst identified AP was located in the upper/lower incisor area and upper molar area. Conclusions PAN showed good diagnostic accuracy, high specificity, and low sensitivity for the detection of endodontically treated AP.

Approaches for Assessment of Response of Bone Metastases to Therapies

The recent introduction of new therapeutic agents has proven alternative options in the management of patients with metastatic castration-resistant prostate cancer (mCRPC). Moreover, other novel agents are being studied and developed. Bone represents the most common site of recurrence in mCRPC, occurring in more than 80 % of cases. The evaluation of treatment efficacy in bone metastatic prostate cancer (PC) is mainly focused on the assessment of patient outcomes, but the behavior of bone metastases and their changes due to the therapy are also of great interest. The impressive development of technologies offers today various options for describing the skeletal changes caused by metastases before, during, and after treatments. At present, in clinical practice, the only laboratory test currently used to measure metastatic bone progression remains prostate-specific antigen (PSA). Great importance has been progressively assumed by new modalities of metabolic imaging, such as 18F fluoride, 18F/11C choline, and 18F FDG positron emission tomography (PET)/computed tomography (CT) that are flanking the traditional bone scan (BS) with 99mTc phosphonates, both with planar acquisition and single-photon emission computed tomography (SPECT). In addition, radiology, besides CT, is proposing the high performance of multimodality magnetic resonance imaging (MRI) that seems to guarantee a very high accuracy in evaluating skeletal involvement.