Average arterial input function for quantitative dynamic contrast enhanced magnetic resonance imaging of neck nodal metastases

Background

We evaluated the repeatability of the calculation of myocardial blood flow (MBF) at rest and pharmacological stress, and calculated the coronary flow reserve (CFR) utilizing ⁸²Rb PET imaging. The aim of the research was to prove high repeatability for global MBF and CFR values and good repeatability for regional MBF and CFR values. The results will have significant impact on cardiac PET imaging in terms of making it more affordable and increasing its use.

Methods

12 normal volunteers were imaged at rest and during pharmacological stress, with 2220 MBq of ⁸²Rb each. A GE Advance PET system was used to acquire dynamic 50-frame studies. MBF was calculated with a 2-compartmental model using a modified PMOD program (PMOD; University Hospital Zurich, Zurich, Switzerland). Two differential equations, describing a 2-compartmental model, were solved by numerical integration and using Levenberg-Marquardt's method for fitting data. The PMOD program defines 16 standard segments and calculates myocardial flow for each segment, as well as average septal, anterior, lateral, inferior and global flow. Repeatability was evaluated according to the method of Bland and Altman.

Results

Global rest and stress MBF, as well as global CFR, showed very good repeatability. No significant differences were found between the paired resting global MBF (0.63 ± 0.13 vs. 0.64 ± 0.13 mL/min/g; mean difference, -1.0% ± 2.6%) and the stress global MBF (1.37 ± 0.23 vs. 1.37 ± 0.24; mean difference, 0.1% ± 2.3%). Global CFR was highly reproducible (2.25 ± 0.56 vs. 2.22 ± 0.54, P = not statistically significant; mean difference, 1.3% ± 14.3%). Repeatability coefficients for global rest MBF were 0.033 (5.2%) and stress MBF 0.062 (4.5%) mL/min/g. Regional rest and stress MBF and CFR have shown good reproducibility. The average per sector repeatability coefficients for rest MBF were 0.056 (8.5%) and stress MBF 0.089 (6.3%) mL/min/g, and average repeatability coefficient for CFR was 0.25 (10.6%).

Conclusion

The results of the study show that software calculation of MBF and CFR with ⁸²Rb myocardial PET imaging is highly repeatable for global values and has good repeatability for regional values.     

FDG-PET Detected Thyroid Incidentalomas: Need for Further Investigation?

Background Incidental thyroid abnormalities are increasingly detected in patients undergoing PET scans. The aim of this study was to review our experience with the management of PET detected thyroid incidentalomas in a large single institution series. Methods All PET scans performed from May 2003 to July 2005 were reviewed and patients with incidental thyroid abnormalities were identified. From this group, patients that underwent further investigation were analyzed. Data relating to PET scan findings, FNA diagnoses, operative details, and histopathology was reviewed. Results In 8,800 patients, 16,300 PET scans were performed of whom 263 patients (2.9% of patients and 1.6% of PET scans) had findings positive for thyroid abnormality. Thyroid malignancy was noted in 42% (24 patients) of the 57 patients that underwent FNA. In the group of 27 patients that were subjected to operative intervention, 74% (20 patients) were noted to have a malignant diagnosis. The final histopathology revealed primary thyroid carcinoma in all these 20 patients (19 patients with papillary carcinoma and one patient with primary thyroid lymphoma). The factors that correlated with an increased risk of malignancy were the presence of physical finding (p = 0.01) and focal (p < 0.01) or unilateral uptake (p < 0.01) on PET scan. The average SUV was not useful in differentiating benign (9.2) from malignant lesions (8.2, p = 0.7). Conclusions PET detected incidental thyroid abnormalities are rare. In patients with positive PET scan findings and suspicious features, the incidence of primary thyroid malignancy is very high. These patients warrant further investigation followed by possible operative intervention.     

The spatial chronnectome reveals a dynamic interplay between functional segregation and integration

The brain is highly dynamic, reorganizing its activity at different interacting spatial and temporal scales, including variation within and between brain networks. The chronnectome is a model of the brain in which nodal activity and connectivity patterns change in fundamental and recurring ways over time. Most literature assumes fixed spatial nodes/networks, ignoring the possibility that spatial nodes/networks may vary in time. Here, we introduce an approach to calculate a spatially fluid chronnectome (called the spatial chronnectome for clarity), which focuses on the variations of networks coupling at the voxel level, and identify a novel set of spatially dynamic features. Results reveal transient spatially fluid interactions between intra‐ and internetwork relationships in which brain networks transiently merge and separate, emphasizing dynamic segregation and integration. Brain networks also exhibit distinct spatial patterns with unique temporal characteristics, potentially explaining a broad spectrum of inconsistencies in previous studies that assumed static networks. Moreover, we show anticorrelative connections to brain networks are transient as opposed to constant across the entire scan. Preliminary assessments using a multi‐site dataset reveal the ability of the approach to obtain new information and nuanced alterations that remain undetected during static analysis. Patients with schizophrenia (SZ) display transient decreases in voxel‐wise network coupling within visual and auditory networks, and higher intradomain coupling variability. In summary, the spatial chronnectome represents a new direction of research enabling the study of functional networks which are transient at the voxel level, and the identification of mechanisms for within‐ and between‐subject spatial variability.     

Bone mineralisation in type 1 glycogen storage disease

Radial bone mineral content (BMC) was measured using single photon absorptiometry in 11 prepubertal children, aged 3.4–12.6 years, with glycogen storage disease type 1 (GSD-1), 2 of whom were receiving granulocyte colony stimulating factor (G-CSF) therapy for chronic neutropenia. Patients were short (median height SD score –1.35, range –3.74 to –0.27), and had reduced BMC Z scores (median 1.79, range –6.35 to +0.27) and radial bone width Z scores (median –0.72, range –2.00 to +0.68). Those receiving G-CSF did not differ significantly from the rest of the group. Generally dietary calcium intake was low and urinary calcium excretion increased. Urinary lactate excretion was high but did not correlate with BMC Z scores. Factors regulating bone metabolism (parathyroid hormone and 25-hydroxy vitamin D concentrations) and markers of bone formation (osteocalcin and skeletal alkaline phosphatase) were not increased implying that there was no compensation for increased bone resorption.Conclusion Patients with GSD-1 may be at increased risk of fracture in later life and require close attention to metabolic control and calcium balance.     

Improved outcomes in patients with osteogenic sarcoma of the head and neck

BACKGROUND: The current study reviews the authors' recent institutional experience in the treatment of osteosarcoma of the head and neck (OSHN). METHODS: The clinical records of 44 patients who were treated between 1981 and 1998 for OSHN were reviewed retrospectively. Archived histologic material was reviewed and data were analyzed to identify factors predictive of disease control and survival. Outcomes were compared with a previously reported historic cohort treated at the study institution. RESULTS: Patients ranged in age from 6 to 64 years (median, 31 years). The mandible was the primary site in 18 patients (41%), the maxilla in 20 patients (45%), and the skull in 6 patients (14%). Surgery was employed in all 44 patients, neoadjuvant chemotherapy was administered in 30 patients (68%), and postoperative radiation therapy was given to 7 patients (16%). The surgical excision margins were positive in 13 patients (30%). High-grade lesions were reported in 50% patients and low-grade lesions were noted in 18% of patients (grade was not assessable in 32%). Histologic response was "unfavorable" in 22 of 30 patients (73%) who were treated with neoadjuvant chemotherapy. The 3-year overall, disease-specific, and recurrence-free survival rates were approximately 81%, 81%, and 73%, respectively (median follow-up of 41 months). Positive surgical margins were found to be the only significant predictor of worse disease-specific survival. Compared with the historical cohort, the current experience demonstrated an obvious improvement in the 5-year local control (35% vs. 78%), distant metastases (37% vs. 13%), and overall survival (23% vs. 70%). CONCLUSIONS: Negative surgical margins were found to be the only significant predictor of overall and disease-specific survival. The results of the current study represent a considerable improvement over the authors' previously published experience and compare favorably with the results reported in the literature.     

Primary mucosal malignant melanoma of the head and neck

INTRODUCTION: The relative rarity of mucosal melanomas of the head and neck (MMHN) has made analysis of treatment approaches difficult. Advances in diagnostic techniques and treatment interventions have had obvious impact on outcomes in cutaneous melanoma, but the effects on outcome in MMHN remain undefined. This study aims to assess the outcome and identify clinical and histologic prognostic indicators in a recent cohort of patients with MMHN treated at a single institution. METHODS: The clinical records of 59 patients with the diagnosis of MMHN treated at Memorial Sloan-Kettering Cancer Center (MSKCC) between 1978 and 1998 were retrospectively reviewed. Pathologic material on each of these patients was prospectively reviewed by at least two pathologists (MP, KB, or AH) for confirmation of diagnosis and assessment of histologic variables. Survival was calculated by the Kaplan-Meier method. Clinical (patient demographics, tumor characteristics, and treatment) and histologic data (tumor thickness, melanosis, melanoma in situ, vascular invasion, and multifocality) were analyzed for impact on outcome by both univariate and multivariate analyses. RESULTS: Thirty-five patients (59%) had sinonasal tumors (SNMM), whereas 24 (41%) had oral (ORMM) tumors. Forty-seven patients (79.6%) were staged as stage I, 8 (13.6%) as stage II, and 4 (6.8%) were classified as stage III. Regional lymphatic metastases at presentation were more frequent in ORMM compared with SNMM (25% vs 6%, p =.05). Surgery was used in all patients. Adjuvant radiation therapy was used more frequently in the SNMM group compared with the ORMM group (40% vs 17%, p =.04). The rates of local failure for ORMM and SNMM were 51% and 50%, nodal failure rates were 42% and 20%, and distant failure rates were 67% and 40%, respectively (p = NS). With a median follow-up of 20 months, the 5-year disease-specific survival rate was 44% (40% for ORMM vs 47% for SNMM, p = NS). Significant prognostic factors for disease-specific survival on univariate analysis included advanced clinical stage at presentation, tumor thickness greater than 5 mm, presence of vascular invasion, and development of nodal and distant metastases. On multivariate analysis, however, regional nodal failure lost significance. CONCLUSIONS: Clinical stage at presentation, tumor thickness greater than 5 mm, vascular invasion on histologic studies, and development of distant failure are the only independent predictors of outcome in MMHN.     

Double floating injuries in lower limb

Die laparoskopische Chirurgie hat sich in den letzten Jahren zunehmend verbreitet und sich für einige Indikationen sogar zum Goldstandard entwickelt. Auch für kolorektale Eingriffe wird der laparoskopische Zugang zunehmend benutzt, wobei jedoch im Hinblick auf die Sicherheit bei onkologischen Koloneingriffen noch keine abschließende Beurteilung möglich ist. Die operative Therapie der Rektumkarzinome, die durch die Einführung der totalen mesorektalen Exzision (TME) zusätzliche Vorteile hinsichtlich der Rate an Lokalrezidiven erfahren hat, war bislang nicht Gegenstand der laparoskopischen Operationstechnik, da die angenommene Lernkurve und die fragliche onkologische Sicherheit einen derartigen Therapieansatz nicht zuließen.In der hier diskutierten Studie wurde bei Patienten mit Rektumkarzinom die Operation mit TME laparoskopisch durchgeführt. Es konnte gezeigt werden, dass sowohl die onkologischen Ergebnisse (Rezidivrate und Überleben) als auch das kurzfristige Outcome (Mortalität und Morbidität) mit den Ergebnissen der konventionell durchgeführten Operation vergleichbar sind. Ferner bleiben für die Patienten die von anderen laparoskopischen Operationen bekannten Vorteile (Schmerzreduktion, frühe Mobilisation, frühe Darmpassage) erhalten. Die Weiterentwicklung der laparoskopischen Technik könnte hier noch weitere Vorteile bringen, sofern die Konversionsrate zum konventionellen Verfahren durch adäquate Patientenselektion begrenzt werden kann.