Impact of concomitant thyroid pathology on preoperative workup for primary hyperparathyroidism

BACKGROUND: The former standard surgical treatment in patients with primary hyperparathyroidism (pHPT) has been bilateral cervical exploration. New localization techniques and the possibility of intraoperative measurement of intact parathormone (iPTH) permit a focused, minimally invasive parathyroidectomy (MIP). The introduction of MIP without complete neck exploration leads to the potential risk of missing thyroid pathology. The aim of the present study is to evaluate the value of MIP in respect to coexisting thyroid findings and their impact on preoperative workup for primary hyperparathyroidism. METHODS: This is a prospective study including 30 consecutive patients with pHPT (median age 65 years; 17 females, 13 males). In all patients preoperative localization was performed by ultrasonography and 99m Tc-MIBI scintigraphy- Intraoperative iPTH monitoring was routinely done. RESULTS: Ten patients (33%) had a concurrent thyroid finding requiring additional thyroid surgery, and two patients (7%) with negative localization results underwent bilateral neck exploration. Therefore, MIP was attempted in 18 (60%) patients. The conversion rate to a four gland exploration was 6% (1/18). The sensitivities of 99m Tc-MIBI scanning and ultrasonography were 83.3% and 76.6%, respectively. The respective accuracy rates were 83.3% and 76.6%. Of note, the combination of the two modalities did not improve the sensitivity and accuracy in our patient population. During a median follow-up of 40 months, none of the patients developed persistent or recurrent hypocalcaemia, resulting in a 100% cure rate. CONCLUSION: Coexisting thyroid pathology is relatively frequent in patients with pHPT in our region. Among patients having pHPT without any thyroid pathology, the adenoma localization is correct with either ultrasonography or 99m Tc-MIBI scintigraphy in the majority of cases. MIP with iPTH monitoring are highly successful in this group of patients and this operative technique should be the method of choice

Feasibility and long-term results of focused radioguided parathyroidectomy using a "low" 37 MBq (1 mCi) (99m)Tc-sestamibi protocol

Aim of the present study was to investigate the feasibility and long-term results of focused radioguided parathyroidectomy using a "low" 37 MBq (1 mCi) (99m)Tc-sestamibi dose protocol compared to conventional "high 740 MBq (20 mCi) (99m)Tc-sestamibi dose protocol" in patients with primary hyperparathyroidism (PHPT). The data of focused radioguided surgery obtained in a group of 320 consecutive PHPT patients with high probability of the presence of a solitary parathyroid adenoma (PA) were studied. All patients underwent preoperative imaging work-up of double-tracer (99m)Tc-pertechnetate/(99m)Tc-sestamibi subtraction parathyroid scintigraphy (Sestamibi scintigraphy) and high resolution neck ultrasound (US). In 301/320 patients (96.6%) focused minimally invasive radioguided surgery was successfully performed by administering a "low" 37 MBq (1 mCi) (99m)Tc-sestamibi dose in the operating room 10 minutes before operation. No major intraoperative complications were recorded. Focused radioguided surgery required a mean time of 32 min and a mean hospital stay of 1.2 days. Local anesthesia was applied in 75 patients, 66 of whom (88%) were patients older than 65 years with comorbidities contraindicating general anesthesia. No case of persistent or recurrent PHPT was observed during post-surgical follow-up (range = 18–70 months; mean +/- SD = 15.3 +/- 9.1 months). Radiation exposure dose to the operating surgeon was 1.2 μSi/hour with the "low 37 MBq (1 mCi) (99m)Tc-sestamibi dose", and less than 1.0 μSi/hour for the other operating-room personnel. Focused low dose radioguided parathyroidectomy is a safe and effective means to localize parathyroid adenomas in patients affected by solitary PA thus reducing by 20 fold the radiation exposure dose to the patients and operating room personnel

Impact of Intraoperative Parathyroid Hormone Monitoring on the Prediction of Multiglandular Parathyroid Disease

Optimal interpretation of the results of intraoperative parathyroid hormone (IOPTH) monitoring during neck exploration for primary hyperparathyroidism (pHPT) is still controversial. The reliability of the “50% rule” in multiglandular disease (MGD) is often disputed, mostly because of competing pathophysiologic paradigms. The aim of this study was to ascertain and corroborate the ability of IOPTH monitoring to detect MGD in a practice, combining conventional and alternative parathyroidectomy techniques. This is a retrospective single institution analysis of 69 consecutive patients undergoing cervical exploration for pHPT by various approaches. The IOPTH measurements were performed after induction of anesthesia but prior to skin incision and 10 minutes after excision of the first visualized enlarged parathyroid gland. In this series, 55 patients (80%) had single adenomas, and 14 patients (20%) had MGD. In 8 of the 14 patients with MGD, IOPTH levels were obtained sequentially after removal of every enlarged gland. Of these 8 patients, 6 (75%) had a false-positive decrease (decrease below 50% of baseline value in presence of another enlarged gland) failing to predict the presence of a second enlarged gland. In 2 cases IOPTH monitoring provided a true-negative result, correctly predicting MGD. If MGD is defined by gross morphologic criteria, IOPTH monitoring fails to predict the presence of MGD reliably. However, if MGD is defined by functional criteria, the course of these patients does not seem significantly affected. The importance of these findings must be further investigated, especially with regard to the outcome of minimally invasive parathyroid procedures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41301/1/268_2003_Article_7255.pd

Different effects of deep inspirations on central and peripheral airways in healthy and allergen-challenged mice

<p>Abstract</p> <p>Background</p> <p>Deep inspirations (DI) have bronchodilatory and bronchoprotective effects in healthy human subjects, but these effects appear to be absent in asthmatic lungs. We have characterized the effects of DI on lung mechanics during mechanical ventilation in healthy mice and in a murine model of acute and chronic airway inflammation.</p> <p>Methods</p> <p>Balb/c mice were sensitized to ovalbumin (OVA) and exposed to nebulized OVA for 1 week or 12 weeks. Control mice were challenged with PBS. Mice were randomly selected to receive DI, which were given twice during the minute before assessment of lung mechanics.</p> <p>Results</p> <p>DI protected against bronchoconstriction of central airways in healthy mice and in mice with acute airway inflammation, but not when OVA-induced chronic inflammation was present. DI reduced lung resistance induced by methacholine from 3.8 ± 0.3 to 2.8 ± 0.1 cmH₂O·s·mL^-1in healthy mice and 5.1 ± 0.3 to 3.5 ± 0.3 cmH₂O·s·mL^-1in acute airway inflammation (both <it>P </it>< 0.001). In healthy mice, DI reduced the maximum decrease in lung compliance from 15.9 ± 1.5% to 5.6 ± 0.6% (<it>P </it>< 0.0001). This protective effect was even more pronounced in mice with chronic inflammation where DI attenuated maximum decrease in compliance from 44.1 ± 6.6% to 14.3 ± 1.3% (<it>P </it>< 0.001). DI largely prevented increased peripheral tissue damping (G) and tissue elastance (H) in both healthy (G and H both <it>P </it>< 0.0001) and chronic allergen-treated animals (G and H both <it>P </it>< 0.0001).</p> <p>Conclusion</p> <p>We have tested a mouse model of potential value for defining mechanisms and sites of action of DI in healthy and asthmatic human subjects. Our current results point to potent protective effects of DI on peripheral parts of chronically inflamed murine lungs and that the presence of DI may blunt airway hyperreactivity.</p

Validation of diffusion tensor MRI measurements of cardiac microstructure with structure tensor synchrotron radiation imaging.

Background Diffusion tensor imaging (DTI) is widely used to assess tissue microstructure non-invasively. Cardiac DTI enables inference of cell and sheetlet orientations, which are altered under pathological conditions. However, DTI is affected by many factors, therefore robust validation is critical. Existing histological validation is intrinsically flawed, since it requires further tissue processing leading to sample distortion, is routinely limited in field-of-view and requires reconstruction of three-dimensional volumes from two-dimensional images. In contrast, synchrotron radiation imaging (SRI) data enables imaging of the heart in 3D without further preparation following DTI. The objective of the study was to validate DTI measurements based on structure tensor analysis of SRI data. Methods One isolated, fixed rat heart was imaged ex vivo with DTI and X-ray phase contrast SRI, and reconstructed at 100 μm and 3.6 μm isotropic resolution respectively. Structure tensors were determined from the SRI data and registered to the DTI data. Results Excellent agreement in helix angles (HA) and transverse angles (TA) was observed between the DTI and structure tensor synchrotron radiation imaging (STSRI) data, where HADTI-STSRI = −1.4° ± 23.2° and TADTI-STSRI = −1.4° ± 35.0° (mean ± 1.96 standard deviation across all voxels in the left ventricle). STSRI confirmed that the primary eigenvector of the diffusion tensor corresponds with the cardiomyocyte long-axis across the whole myocardium. Conclusions We have used STSRI as a novel and high-resolution gold standard for the validation of DTI, allowing like-with-like comparison of three-dimensional tissue structures in the same intact heart free of distortion. This represents a critical step forward in independently verifying the structural basis and informing the interpretation of cardiac DTI data, thereby supporting the further development and adoption of DTI in structure-based electro-mechanical modelling and routine clinical applications

Quantifying Heterogeneity in Host-Vector Contact: Tsetse (Glossina swynnertoni and G. pallidipes) Host Choice in Serengeti National Park, Tanzania

Identifying hosts of blood-feeding insect vectors is crucial in understanding their role in disease transmission. Rhodesian human African trypanosomiasis (r-HAT or ‘sleeping sickness’) caused by Trypanosoma brucei rhodesiense and transmitted by tsetse flies, is commonly associated with wilderness areas of east and southern Africa. Such areas hold a diverse range of species which form communities of hosts for disease maintenance. The relative importance of different wildlife hosts remains unclear. This study quantified tsetse feeding preferences in a wilderness area of great host species richness, Serengeti National Park, Tanzania, assessing tsetse feeding and host density contemporaneously. Glossina swynnertoni and G.pallidipes were collected from six study sites. Bloodmeal sources were identified through matching Cytochrome B sequences amplified from bloodmeals from fed flies to published sequences. Densities of large mammal species in each site were quantified, and feeding indices calculated to assess the relative selection or avoidance of each host species by tsetse. The host species most commonly identified in G. swynnertoni bloodmeals, warthog (94/220), buffalo (48/220) and giraffe (46/220), were found at relatively low densities (3-11/km2) and fed on up to 15 times more frequently than expected by their relative density. Wildebeest, zebra, impala and Thomson’s gazelle, found at the highest densities, were never identified in bloodmeals. Commonly identified hosts for G. pallidipes were buffalo (26/46), giraffe (9/46) and elephant (5/46). This study is the first to quantify tsetse host range by molecular analysis of tsetse diet with simultaneous assessment of host density in a wilderness area. Although G.swynnertoni and G.pallidipes can feed on a range of species, they are highly selective. Many host species are rarely fed on, despite being present in areas where tsetse are abundant. These feeding patterns, along with the ability of key host species to maintain and transmit T.b.rhodesiense, drive the epidemiology of r-HAT in wilderness areas