Prospective comparison of simultaneous [68Ga]Ga-PSMA-11 PET/MR versus PET/CT in patients with biochemically recurrent prostate cancer.

OBJECTIVES: PSMA-PET has become the PET technique of choice to localise the site of biochemically recurrent prostate cancer (PCa). With hybrid PET/MRI, the advantages of MRI are added to molecular characteristic of PET. The aim of this study was to investigate the incremental value of PET/MR versus PET/CT in patients with biochemically recurrent PCa by head-to-head comparison. METHODS: Thirty-four patients with biochemically recurrent PCa were prospectively included. They underwent [68Ga]Ga-PSMA-11 PET/CT, followed by simultaneous PET/MR. All PET (PETCT, PETMR), CT and MR images were evaluated for number of lesions and location. The number of lesions at specific sites was compared using Wilcoxon-sign-rank test. For PET, the maximum and mean standardised uptake values (SUVs) were calculated for each lesion compared using a two-sided paired t test. RESULTS: PETCT and PETMR scans were positive in 19 and 20 patients, detecting 73 and 79 lesions respectively. All lesions detected on PETCT were also detected on PETMR. CT and MRI only were positive in 14 and 17 patients, detecting 38 and 50 lesions, respectively, which was significantly lower than PETCT and PETMR respectively. Combined interpretation showed more lesions on PET/MR than on PET/CT (88 vs 81). No significant difference in detection of presence of local recurrence nor distant metastases was found. SUVmean and SUVmax values were significantly higher on PETMR than on PETCT in local recurrence and lymph node metastases. CONCLUSIONS: [68Ga]Ga-PSMA-11 PET/MR was able to detect biochemically recurrent PCa at least as accurately as PET/CT for local recurrence, lymph node metastasis and distant metastasis. KEY POINTS: • PSMA PET/MRI detects the location of biochemical recurrence at least as accurately as PET/CT. • Substitution of PET/CT by PET/MRI adds sensitivity in PSMA lesion detection also in the setting of distant recurrence due to both the MR and TOF PET components.

On the optimal z-score threshold for SISCOM analysis to localize the ictal onset zone.

BACKGROUND: In epilepsy patients, SISCOM or subtraction ictal single photon emission computed tomography co-registered to magnetic resonance imaging has become a routinely used, non-invasive technique to localize the ictal onset zone (IOZ). Thresholding of clusters with a predefined number of standard deviations from normality (z-score) is generally accepted to localize the IOZ. In this study, we aimed to assess the robustness of this parameter in a group of patients with well-characterized drug-resistant epilepsy in whom the exact location of the IOZ was known after successful epilepsy surgery. Eighty patients underwent preoperative SISCOM and were seizure free in a postoperative period of minimum 1 year. SISCOMs with z-threshold 2 and 1.5 were analyzed by two experienced readers separately, blinded from the clinical ground truth data. Their reported location of the IOZ was compared with the operative resection zone. Furthermore, confidence scores of the SISCOM IOZ were compared for the two thresholds. RESULTS: Visual reporting with a z-score threshold of 1.5 and 2 showed no statistically significant difference in localizing correspondence with the ground truth (70 vs. 72% respectively, p = 0.17). Interrater agreement was moderate (κ = 0.65) at the threshold of 1.5, but high (κ = 0.84) at a threshold of 2, where also reviewers were significantly more confident (p < 0.01). CONCLUSIONS: SISCOM is a clinically useful, routinely used modality in the preoperative work-up in many epilepsy surgery centers. We found no significant differences in localizing value of the IOZ using a threshold of 1.5 or 2, but interrater agreement and reader confidence were higher using a z-score threshold of 2.

Bone scan findings in calcific tendinitis at the gluteus maximus insertion: some illustrative cases.

We describe the bone scan and single-photon emission computed tomography/computed tomography findings in calcific tendinitis of the gluteus maximus and discuss its pathophysiology. Although this tendinopathy is mostly self-limiting, awareness of this disease is important for 2 reasons. First, it may explain acute hip symptoms in patients in the resorptive phase of the calcifications. Second, it should be considered as a differential diagnosis for bone scan hot spots in the vicinity of the gluteus maximus tendon and for cortical erosion seen in that region on X-rays or CT.

Value of 18fluorodeoxyglucose-positron-emission tomography in amyotrophic lateral sclerosis: a prospective study.

IMPORTANCE: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder primarily affecting the motor system, with extramotor involvement to a variable extent. Biomarkers for early differential diagnosis and prognosis are needed. An autosomal dominant hexanucleotide (GGGGCC) expansion in the noncoding region of the chromosome 9 open reading frame 72 (C9orf72) gene is the most frequent genetic cause of ALS, but its metabolic pattern has not been studied systematically. OBJECTIVES: To evaluate the use of 18fluorodeoxyglucose-positron-emission tomography as a marker of ALS pathology and investigate whether a specific metabolic signature is present in patients with C9orf72 mutations. DESIGN, SETTING, AND PARTICIPANTS: In total, 81 patients with a suspected diagnosis of ALS at University Hospital Leuven were prospectively investigated. All underwent detailed neurological examination and electrodiagnostic and genetic testing for the major known genetic causes of ALS (C9orf72, SOD1, TARDBP, and FUS). A diagnosis of ALS was made in 70 of 81 patients. Of these, 11 were C9orf72 positive and 59 were C9orf72 negative. In 7 patients, the diagnosis of primary lateral sclerosis was made; 4 patients had progressive muscular atrophy. A screened healthy control population was used for comparison. MAIN OUTCOMES AND MEASURES: Positron-emission tomographic data were spatially normalized and analyzed using a predefined volume of interest and a voxel-based analysis (SPM8). Discriminant analysis was done both volume of interest based and voxel based using a support vector machine approach. RESULTS: Compared with control participants, 18fluorodeoxyglucose-positron-emission tomography showed perirolandic and variable prefrontal hypometabolism in most patients. Patients with primary lateral sclerosis showed a similar pattern. Patients with C9orf72-positive ALS had discrete relative hypometabolism in the thalamus and posterior cingulate compared with those with C9orf72-negative ALS. A posteriori-corrected discriminant analysis was able to correctly classify 95% of ALS cases and 71% of primary lateral sclerosis cases. Prefrontal hypometabolism was associated with reduced clinical functioning (ALS Functional Rating Scale). Extensive hypometabolism in the prefrontal or anterior temporal areas was present in 10% of patients and associated with significantly shorter survival as an independent factor (n = 63, P < .001). Patients who were C9orf72 positive did not differ in survival compared with those who were C9orf72 negative. CONCLUSIONS AND RELEVANCE: 18Fluorodeoxyglucose-positron-emission tomography is a useful early diagnostic and prognostic marker for ALS. Amyotrophic lateral sclerosis that is positive for C9orf72 is characterized by only mild cerebral metabolic differences that show no prognostic difference.

The sensitivity of somatic symptoms in post-stroke depression: a discriminant analytic approach.

BACKGROUND: Somatic and neurocognitive symptoms of depression may overlap with the physical symptoms of stroke, and thus make the diagnosis of post-stroke depression difficult. AIM: To assess the sensitivity of individual depressive symptoms and their contribution to the diagnosis of post-stroke depression. PATIENTS AND METHODS: Two hundred and six patients with first-ever stroke, participating in a longitudinal study, were administered the Structured Clinical Interview for DSM-IV and the Hamilton Depression Rating Scale (HAM-D). In a discriminant analysis the relative contribution of the individual HAM-D items to the diagnosis of major depressive disorder was evaluated. RESULTS: The cumulative incidence of post-stroke major depressive disorder was 32%. The discriminant model based on HAM-D item scores was highly significant (p<0.001) and classified 88.3% of patients correctly as depressed or nondepressed. As expected, 'depressed mood' discriminated best between depressed and non-depressed stroke patients. 'Reduced interests' had a relatively low sensitivity and may in part reflect 'apathy', which often is considered a separate construct. With the exception of 'suicidal thoughts', most psychological symptoms, such as 'hypochondriasis', 'lack of insight' and 'feelings of guilt', were not very sensitive. Some somatic symptoms, such as 'reduced appetite', 'psychomotor retardation', and 'fatigue' had high discriminative properties. CONCLUSION: Psychological, neurocognitive and somatic symptoms of depression differ among themselves in terms of diagnostic sensitivity, and should be considered individually. Some somatic symptoms are highly sensitive for depression and should not be neglected by following an 'exclusive' or 'attributional' approach to the diagnosis of PSD.