Preoperative Imaging for Resectable Periampullary Cancer: Clinicopathologic Implications of Reported Radiographic Findings

Background

High-resolution, multiphase, computed tomography (CT) is a standard preoperative test prior to pancreatectomy, yet the clinical significance of routinely reported findings remains unknown.

Methods

We identified patients who underwent a pancreaticoduodenectomy for a periampullary adenocarcinoma (PA) over the previous 5 years and had a pancreas protocol CT at our institution. Clinicopathologic implications of reported CT findings were evaluated.

Results

There were 155 pancreatic ductal adenocarcinomas (PDA) and 47 non-pancreatic PAs. No mass was visualized on CT in 6 % of PDAs and 23 % of non-pancreatic PA. A size discrepancy of ≥1 cm between radiographic and pathologic tumor diameters was observed in 40 % of PAs, with CT underestimating the size in most instances (75 %). Radiographically enlarged lymph nodes were not associated with true lymph node metastases in PDAs (70 % lymph node positive cases were enlarged on CT vs 74 % lymph node negative, p = 0.5), but were associated with a preoperatively placed biliary endoprosthesis (63 % with endoprosthesis were enlarged vs 37 % no endoprosthesis, p = 0.013). Major visceral vessel involvement on CT was not associated with a vascular resection (3 % with CT vessel involvement vs 2 % without, p = 0.8) or a positive uncinate resection margin (24 vs 20 %, respectively, p = 0.6).

Discussion

While dedicated pancreas protocol CT provides unprecedented detail, the test may lead to overinterpretation of the extent of disease in some instances. A radiographic suggestion of enlarged lymph nodes and vascular involvement does not necessarily preclude exploration with curative intent. CTs with local disease should be reported in an objective template and carefully reviewed by a multidisciplinary group of surgeons, radiologists, and oncologists to avoid missing an opportunity for neoadjuvant therapy or cure by resection.     

Systematic review of the diagnostic utility of SPECT imaging in dementia

Single-photon emission-computed tomography (SPECT) may potentially contribute to the diagnostic work up of patients with neurodegenerative dementia. This systematic review aims to establish the diagnostic utility of ^99mTc-hexamethylpropyleneamine (^99mTc-HMPAO) and ^99mTc-ethylcysteine dimer SPECT in distinguishing between Alzheimer’s disease (AD) and frontotemporal dementia (FTD), AD and vascular dementia (VD), AD and dementia with Lewy bodies (DLB), and AD and normal controls (NC). We searched MEDLINE and Embase databases via OVID for articles from January 1985 to May 2012 and identified additional studies from reviews and references. Of 755 studies, 49 studies met the inclusion and exclusion criteria for this systematic review; AD versus FTD (n = 13), AD versus VD (n = 18), AD versus DLB (n = 5), and AD versus NC (n = 18). We compiled relevant data and graded the studies with an internal and external validity criteria checklist. We pooled the studies with a clinical diagnosis and those using ^99mTc-HMPAO SPECT in a meta-analysis, calculating the pooled weighted sensitivity, specificity, likelihood ratios, and diagnostic odds ratios using DerSimonian–Laird random-effects model. The pooled weighted sensitivity and specificity of ^99mTc-HMPAO-SPECT in distinguishing clinically diagnosed AD from FTD are 79.7 and 79.9 %, respectively, AD from VD are 74.5 and 72.4 %, AD from DLB are 70.2 and 76.2 %, and AD from NC are 76.1 and 85.4 %. SPECT does have diagnostic value, particularly in differentiating Alzheimer’s disease from frontotemporal dementia and normal controls; however, it should not be used in isolation, rather as an adjunct, and interpreted in the context of clinical information and paraclinical test results.     

The effect of screw length on fracture load and abutment strain in dental implants with external abutment connections

Purpose: One of the most common types of failure in dental implants is fracture of the abutment screw, after which the remnant is usually not easily removed. The purpose of this study was to investigate the effect of abutment screw length on the amount of screw resistance load and strain after loading. Materials and Methods: Twenty-one implants and straight abutments were prepared. The implants were placed in acrylic resin blocks at an angle of 30 degrees relative to the long axis. The abutment screws were prepared and classified into seven groups based on length (n = 3 abutments per group). The implants and abutments were joined with a torque of 30 Ncm. Strain gauges were attached to the abutments, and the implant-abutment assemblies were compressed. Curves of strain over time, peak load, and load at fracture were measured. Linear models of the variables over the abutment screw length were analyzed. Results: The break and peak loads were significantly associated with abutment screw length. However, all measured break and peak loads were greater than the maximal occlusal force. There were no significant changes in peak or break strain values associated with screw length (P > .05). Conclusions: Clinically, fractured abutment screws may be replaced by shorter abutment screws without removal of the broken screw remnant.     

Umbilical cord prostaglandins in term and preterm parturition

Objective: Prostaglandins (PGs) are considered the universal mediators of parturition. Amniotic fluid PGE₂ and PGF_2α concentrations increase before the onset of spontaneous labor at term, as well as during labor. This study was conducted to determine if the concentrations of umbilical cord PGE₂ and PGF₂α change with advancing gestational age, spontaneous labor at term, and preterm labor (with and without funisitis).

Methods: Umbilical cord (UC) tissue samples were obtained from women (N?=?158) with singleton pregnancies in the following groups: (1) term deliveries without labor (TNL; n?=?20); (2) term deliveries with labor (TIL; n?=?20); (3) spontaneous preterm deliveries (sPTD) with (n?=?20) and without acute funisitis (n?=?20); and (4) preeclampsia without labor (n?=?78). The concentrations of PGs were determined in different locations of the UC. PGE₂ and PGF_2α were measured by specific immunoassays. Non-parametric statistics were used for analysis.

Results: (1) In spontaneous preterm deliveries, the median UC PGE₂ concentration was higher in cases with funisitis than in those without funisitis (233.7?pg/µg versus 87.4?pg/µg of total protein, p?=?0.001); (2) the median UC PGE₂ concentration in sPTD with funisitis was also higher than that obtained from samples who had undergone labor at term (233.7?pg/µg versus 116.1?pg/µg of total protein, p?=?0.03); (3) the UC PGE₂ and PGF_2α concentration increased as a function of advancing gestational age before 36 weeks (PGE₂: ρ?=?0.59, p?<?0.001; PGF_2α: ρ?=?0.39, p?=?0.01), but not after 36 weeks (PGE₂: ρ?=??0.1, p?=?0.5; PGF_2α: ρ?=??0.2, p?=?0.2); (4) the median UC concentrations of PGE₂ and PGF_2α at term was similar in samples obtained from women with and without labor (PGE₂: TNL 133.7?pg/µg versus TIL 116.1?pg/µg of total protein, p?=?0.9; PGF_2α: TNL 8.4?pg/µg versus TIL 8.1?pg/µg of total protein, p?=?0.7); and (5) there was no correlation between UC PG concentration and gestational age at term pregnancy (PGE₂: ρ?=?0.01, p?=?0.9; PGF_2α: ρ?=?0.07, p?=?0.7).

Conclusions: (1) PGE₂ concentrations in the UC are higher in the presence of acute funisitis than in the absence of this lesion; (2) spontaneous labor at term was not associated with a change in the UC concentration of PGE₂ and PGF_2α; and (3) the UC concentrations of PGE₂ and PGF_2α increased as a function of gestational age. We propose that UC PGs act as inflammatory mediators generated in the context of fetal systemic inflammation.