The role of dopamine dysregulation and evidence for the transdiagnostic nature of elevated dopamine synthesis in psychosis: a positron emission tomography (PET) study comparing schizophrenia, delusional disorder, and other psychotic disorders.

There have been few studies performed to examine the pathophysiological differences between different types of psychosis, such as between delusional disorder (DD) and schizophrenia (SZ). Notably, despite the different clinical characteristics of DD and schizophrenia (SZ), antipsychotics are deemed equally effective pharmaceutical treatments for both conditions. In this context, dopamine dysregulation may be transdiagnostic of the pathophysiology of psychotic disorders such as DD and SZ. In this study, an examination is made of the dopamine synthesis capacity (DSC) of patients with SZ, DD, other psychotic disorders, and the DSC of healthy subjects. Fifty-four subjects were recruited to the study, comprising 35 subjects with first-episode psychosis (11 DD, 12 SZ, 12 other psychotic disorders) and 19 healthy controls. All received an 18F-DOPA positron emission tomography (PET)/magnetic resonance (MR) scan to measure DSC (Kocc;30-60 value) within 1 month of starting antipsychotic treatment. Clinical assessments were also made, which included Positive and Negative Syndrome Scale (PANSS) measurements. The mean Kocc;30-60 was significantly greater in the caudate region of subjects in the DD group (ES = 0.83, corrected p = 0.048), the SZ group (ES = 1.40, corrected p = 0.003) and the other psychotic disorder group (ES = 1.34, corrected p = 0.0045), compared to that of the control group. These data indicate that DD, SZ, and other psychotic disorders have similar dysregulated mechanisms of dopamine synthesis, which supports the utility of abnormal dopamine synthesis in transdiagnoses of these psychotic conditions.

Is virtual endoscopy of the middle ear useful?

Virtual endoscopy is a relatively new imaging technology in otology, and therefore data on its efficacy in clinical situations are limited. We conducted a prospective study to evaluate the clinical relevance of radiologic diagnoses based on virtual endoscopy of the middle ear. Our patient population was made up of 30 adults who were scheduled to undergo surgery to correct conductive hearing loss of unknown etiology. Virtual endoscopy was performed on three-dimensional images that were constructed from images obtained with conventional two-dimensional computed tomography (CT). Findings on virtual endoscopy were then compared with the subsequent surgical findings. Virtual endoscopy suggested a middle ear pathology in 19 patients and a normal middle ear in 11 patients. Postoperatively, we found that the virtual diagnoses correlated moderately well with the surgical findings in the group of patients with predicted pathology; 13 of these 19 patients were found to have middle ear problems such as ossicular chain anomalies, otosclerosis, and cholesteatoma (positive predictive value: 68%). However, among the 11 patients whose middle ear structures were radiologically predicted to be normal, only 2 had negative middle ear findings on surgical exploration; of the remaining 9 patients, 8 had otosclerosis and 1 had malleus fixation (negative predictive value: 18%). Thus, the sensitivity and specificity of virtual endoscopy were 59 and 25%, respectively. Virtual endoscopy provides images from a surgeon's perspective, and so it has the potential to be useful in the preoperative evaluation of the middle ear cavity. With ongoing advancements in computer systems and imaging techniques, the cost, reliability, and efficacy of virtual endoscopy may improve. However, further clinical validation and cost-benefit analysis are required before we can determine if it has any additional advantages over conventional two-dimensional CT.

Correlating MRI and histologic tumor thickness in the assessment of oral tongue cancer.

OBJECTIVE: Tumor thickness in oral tongue cancer is an important independent prognostic factor for local recurrence, nodal metastasis, and patient survival. An accurate preoperative assessment of tumor thickness is therefore essential for optimal treatment planning. The aim of our study was to evaluate the accuracy of MRI findings for the preoperative measurement of tumor thickness. SUBJECTS AND METHODS. Eighteen patients with oral tongue cancer underwent preoperative MRI of the tongue. After surgery, the glossectomy specimens were serially sectioned. The radiologic tumor thickness of contrast-enhanced T1-weighted and T2-weighted images was compared with the histologic tumor thickness using our proposed tumor thickness staging classifications. These included stage I (tumor < or = 3 mm), stage II (> 3 mm but < or = 9 mm) and stage III (> 9 mm). RESULTS: The overall accuracy in assessment of proposed tumor thickness staging using contrast-enhanced T1-weighted and T2-weighted images was 83% and 56%, respectively. The radiologic tumor thickness as measured on contrast-enhanced T1-weighted and T2-weighted images had significant correlation with histologic tumor thickness (R = 0.938 and 0.941, respectively). CONCLUSION: MR images provide satisfactory accuracy for the measurement of tumor thickness and staging of oral tongue cancer. Preoperative MRI is recommended to assist in treatment planning for patients with this disease.