Analysis of predictability of F-18 fluorodeoxyglucose-PET/CT in the recurrence of papillary thyroid carcinoma

Whether preoperative F-18 fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) can predict recurrence of papillary thyroid carcinoma (PTC) remains unclear. Herein, we evaluated the potential of primary tumor FDG avidity for the prediction of tumor recurrence in PTC patients. A total of 412 PTC patients (72 males, 340 females; age: 47.2 ± 12.2 years; range: 17-84 years) who underwent FDG-PET/CT prior to total thyroidectomy (n = 350), subtotal thyroidectomy (n = 2), or lobectomy (n = 60) from 2007 to 2011 were analyzed. The predictive ability for recurrence was investigated among various clinicopathological factors, BRAFV600E mutation, and preoperative FDG avidity of the primary tumor using Kaplan-Meier (univariate) and Cox proportional hazards regression (multivariate) analyses. Of the 412 patients, 19 (4.6%) experienced recurrence, which was confirmed either by pathology (n = 17) or high serum thyroglobulin level (n = 2), during a mean follow-up period of 43.9 ± 16.6 months. Of the 412 patients, 237 (57.5%) had FDG-avid tumors (maximum standardized uptake value, 7.1 ± 7.0; range: 1.6-50.5). Kaplan-Meier analysis revealed that tumor size (P = 0.0054), FDG avidity of the tumor (P = 0.0049), extrathyroidal extension (P = 0.0212), and lymph node (LN) stage (P < 0.0001) were significant predictors for recurrence. However, only LN stage remained a significant predictor in the multivariate analysis (P < 0.0001). Patients with FDG-avid tumors had higher LN stage (P < 0.0001), larger tumor size (P < 0.0001), and more frequent extrathyroidal extension (P < 0.0001). In conclusion, FDG avidity of the primary tumor in preoperative FDG-PET/CT could not predict the recurrence of PTC. LN stage was the only identified predictor of PTC recurrence.

Validity of breast-specific gamma imaging for Breast Imaging Reporting and Data System 4 lesions on mammography and/or ultrasound

Purpose

The purpose of this study was to assess the breast-specific gamma imaging (BSGI) in Breast Imaging Reporting and Data System (BI-RADS) 4 lesions on mammography and/or ultrasound.

Methods

We performed a retrospective review of 162 patients who underwent BSGI in BI-RADS 4 lesions on mammography and/or ultrasound.

Results

Of the 162 breast lesions, 66 were malignant tumors and 96 were benign tumors. Sensitivity and specificity of BSGI were 90.9% and 78.1%, and positive predictive value and negative predictive value were 74.1% and 92.6%. The sensitivity or specificity of mammography and ultrasound were 74.2% and 56.3% and 87.9% and 19.8%, respectively. The sensitivity and specificity of BSGI for breast lesions ≤1 cm were 88.0% and 86.8%, while the values of beast lesions >1 cm were 92.7% and 61.5%. The sensitivity or specificity of BSGI and mammography for patients with dense breasts were 92.0% and 81.3% and 72.0% and 50.0%, respectively. 26 patients showed neither a nodule nor microcalcification on ultrasound, but showed suspicious calcification on mammography. The sensitivity and specificity of BSGI with microcalcification only lesion were 75.0% and 94.4%.

Conclusion

This study demonstrated that BSGI had shown high sensitivity and specificity, as well as positive and negative predictive values in BI-RADS 4 lesions on ultrasound and/or mammography. BSGI showed excellent results in dense breasts, in lesions that are less than 1 cm in size and lesions with suspicious microcalcification only.

Prognostic Value of FDG-PET/CT Total Lesion Glycolysis for Patients with Resectable Distal Bile Duct Adenocarcinoma

AIM

We investigated the prognostic value of clinicopathological factors in patients with a distal bile duct adenocarcinoma after curative resection.

PATIENTS AND METHODS

This retrospective study included 25 patients who underwent (18)F-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG-PET/CT) before surgery. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured using FDG-PET/CT. FDG-PET/CT parameters and other clinicopathological factors were assessed to evaluate survival.

RESULTS

Univariate survival analysis showed that high TLG, high MTV, and high SUVmax were significant prognostic predictors for poor overall survival. For progression-free survival, high TLG and large tumor size were significant predictors for a poor prognosis. After multivariate survival analysis, only high TLG was an independent prognostic predictor for poor overall survival (p=0.025).

CONCLUSION

Preoperative assessment of TLG by FDG-PET/CT might be a useful prognostic predictor in patients with a distal bile duct adenocarcinoma after curative resection.

Detection of skeletal muscle metastasis: torso FDG PET-CT versus contrast-enhanced chest or abdomen CT

BACKGROUND

Skeletal muscle metastasis (SMM) in cancer patients has not been sufficiently evaluated regarding prevalence and proper method of detection.

PURPOSE

To determine the prevalence of SMM and compare the diagnostic competencies for SMM of torso F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) and contrast-enhanced chest or abdomen CT.

MATERIAL AND METHODS

We investigated 18,225 PET-CT studies of 6359 cancer patients performed from 2005 to 2012. The PET-CT studies describing potential SMM were retrieved and the corresponding medical records were reviewed. The gold standard for SMM was histopathologically-proven SMM or imaging study-based disease progression. The detectability of SMM was compared between PET-CT and contrast-enhanced CT.

RESULTS

Twenty-six patients had 84 SMM lesions, representing a SMM prevalence of 0.41%. Lung cancer was the most common SMM-associated malignancy (54%) and the gluteal/pelvic girdle muscle was the most frequently involved SMM site (37%). All 84 SMM lesions were visualized on PET-CT (100%). Of these PET-CT positive 84 SMM lesions, 51 lesions were in the CT field of view (FOV) (61%), whereas 33 lesions were out of the CT FOV (39%). Among these 51 lesions, 17 lesions showed rim-enhancing nodules/masses (33%), eight lesions showed homogeneously enhancing nodules (16%), three lesions showed heterogeneously enhancing nodules (6%), and 23 SMM lesions (45%) were non-diagnostic by CT. All 51 SMM lesions within CT FOV were detected on PET-CT (100%), whereas only 28 were visualized on CT (54.9%), resulting in a significant difference (P < 0.005). On average, 2.6 more organs with concomitant metastases were found when SMM was revealed by PET-CT.

CONCLUSION

The prevalence of SMM was as low as 0.41% in the current large cohort of cancer patients. Torso PET-CT was a more competent modality than contrast-enhanced CT in the detection of SMM.

Clinical features of lung adenocarcinomas with epidermal growth factor receptor mutations and miliary disseminated carcinomatosis

Background

We have occasionally encountered advanced lung cancer patients with disseminated carcinomatosis throughout the body and/or within the lung. This study investigated the clinical characteristics and outcomes of advanced lung adenocarcinoma patients with miliary disseminated carcinomatosis.

Methods

Patients with adenocarcinomas harboring epidermal growth factor receptor (EGFR) mutations who presented with miliary disseminated carcinomatosis (either intrapulmonary or distant site) were enrolled in the study. Clinical characteristics, treatment responses, and survival outcomes were collected from medical records.

Results

The most frequent EGFR mutation was an in-frame deletion in exon 19 (n = 44, 68.8%). Arginine substitution of leucine 858 in exon 21 and alanine substitution of glycine 719 in exon 18 were detected in 19 patients (29.7%) and one patient (1.6%), respectively. Patients with miliary disseminated carcinomatosis tended to be female and non-smokers. They expressed the E19 deletion more frequently than patients without miliary dissemination and had shorter progression-free survival times in response to EGFR tyrosine kinase inhibitors (9.7 vs. 12.8 months, P = 0.003) and poorer overall survival (15.9 vs. 29.0 months, P = 0.077). Multivariate analyses revealed that metabolic tumor volume correlated with shorter overall survival time.

Conclusions

Our data indicate that lung adenocarcinoma patients with miliary dissemination have relatively shorter survival times than those without miliary dissemination. The poor prognosis of patients with miliary dissemination may reflect a high tumor burden, as represented by metabolic tumor volume.

Charcoal-induced granuloma that mimicked a nodal metastasis on ultrasonography and FDG-PET/CT after neck dissection

Charcoal can be used for preoperative localization of metastatic lymph nodes in the neck. Charcoal remains stable without causing foreign body reactions during as hort period. However, foreign body reactions may develop if charcoal is left in situ for more than 6 months. We reported a case of charcoal granuloma mimicking local recurrence on fluorodeoxyglucose-positron emission tomography/computed tomography and ultrasonography in a 47-year-old woman who had cervical lymph node dissection due to metastatic invasive ductal carcinoma of the breast.

The prognostic significance of pretreatment [18F]FDG-PET/CT imaging in patients with uterine cervical cancer: preliminary results

PURPOSE OF INVESTIGATION

To evaluate the prognostic significance of positron emission tomography/computed tomography (PET/CT) in patients diagnosed with cervical cancer.

MATERIALS AND METHODS

Patients with cervical cancer in FIGO Stages IB1 to IVB were imaged with PET/CT prior to treatment during one of the staging work-ups. The patients were observed for a median of 31.4 months (range, six to 89 months) after the initial treatment. The standardized uptake value (SUV) max of the primary cervical tumor mass was compared with the prognostic factors. RESULTs: A total of 81 patients who were primarily treated with radical hysterectomy (RH, n = 45) or concurrent chemoradiation (CCRT, n = 36) were analyzed. Multivariate analysis indicated that larger tumor size (> 4 cm, OR 8.694, 95% CI, 1.638-46.146), deep stromal invasion (≥ 1 cm, OR 7.249, 95% CI, 1.141-46.039) by the primary tumor, and pathologically confirmed pelvic lymph node involvement (positive, OR 14.586, 95% CI, 2.072-102.674) were significantly associated with recurrence after treatment. However, pretreatment SUVmax was not a significant independent predictor of disease recurrence (OR 1.058, 95% CI, 0.255-4.398).

CONCLUSION

[18F]Fluorodeoxyglucose (FDG) uptake by the primary tumor showed a significant association with several risk factors that have been identified as treatment predictors. However, a high pretreatment SUVmax was not predictive of recurrence in uter- ine cervical cancer patients.

Retinal sensitivity assessed by microperimetry and corresponding retinal structure and thickness in resolved central serous chorioretinopathy

PURPOSE

To investigate the relationship between retinal sensitivity (RS) assessed by microperimetry (MP) and retinal structural changes in patients with resolved central serous chorioretinopathy (CSC).

METHODS

Spectral domain optical coherence tomography (OCT) examination and MP tests were performed in patients with resolved CSC. Point-to-point correlation was performed between RS and corresponding retinal structural changes using Pearson's correlation analysis. In addition, in a 1-mm zone in the central fovea, a correlation was calculated between the mean RS and the mean central retinal thickness (CRT).

RESULTS

Eighty-four eyes were analyzed. The total number of MP test points was 1092 (84 eyes × 13 points). The mean RS and retinal point thickness (RPT) of all test points were 13.53±3.84 dB and 208.6±48.0 μm, respectively. The RS and RPT were significantly decreased in the test points with loss of the ellipsoid portion of the inner segments (EPIS) (P<0.0001). Within the 1-mm foveal center zone, there was a significant correlation between mean RS and mean CRT (r=0.432, P<0.0001) and between RS and the corresponding RPT (r=0.339, P<0.0001).

CONCLUSION

RS was dependent on the status of the EPIS in patients with resolved CSC. The correlation between mean RS and mean CRT was compatible with the point-to-point correlation between RS and the corresponding RPT.

Pleural Metastasis as Initial Presentation of Occult Gastric Cardia Cancer: A Possible Role of PET-CT in Diagnosis

We report on a case of malignant pleural effusion as initial metastatic presentation of occult gastric cardia cancer in a young woman. To the best of our knowledge, this is the first report of gastric adenocarcinoma metastasized to pleura as an initial presentation. Location of cardia and signet ring cell histology may contribute to the manifestation. Utilization of positron emission tomography-computed tomography was helpful for proper diagnosis. For patients with such distinct clinical presentations, it would be appropriate to consider gastric cancer as one of the possible primary sites.

131I-MIBG targeting of neuroblastoma cells is acutely enhanced by KCl stimulation through the calcium/calmodulin-dependent kinase pathway

The efficacy of (131)I-metaiodobenzylguanidine (MIBG) therapy relies on norepinephrine transporter (NET) function. The ionic make-up of the extracellular fluid critically controls neuronal cell activity and can also affect substrate transport. In this study, we explored the effect of treatment with elevated KCl concentration on MIBG uptake in SK-N-SH neuroblastoma cells. KCl stimulation caused a rapid increase of (131)I-MIBG uptake in a manner that was calcium-dependent and accompanied by activation of calcium/calmodulin-dependent protein kinase (CaMK)II. The effect was completely abolished by KN93, an inhibitor of CaMKI, II, and IV. STO609, a selective inhibitor of CaMK kinase required for activation of CaMKI and IV, but not CaMKII, only modestly attenuated the response. The KCl effect was also completely abrogated by ML7, a selective inhibitor of myosin light chain kinase (MLCK). This restricted form of CaMK activates myosin, which is required for vesicle trafficking. Saturation kinetic analysis revealed KCl stimulation to increase maximal transport velocity without affecting substrate affinity. In conclusion, KCl stimulation rapidly upregulates NET function through the CaMK pathway via activation of CaMKII and MLCK. These findings allow a better understanding of how NET function is acutely modulated by the ionic environment, which in turn may ultimately help improve the efficacy of (131)I-MIBG therapy.

Gastric cancers with microsatellite instability exhibit high fluorodeoxyglucose uptake on positron emission tomography

BACKGROUND

Gastric cancers exhibit various degrees of (18)F-fluorodeoxyglucose (FDG) uptakes on positron emission tomography/computed tomography (PET/CT) imaging. The aim of this study was to evaluate whether FDG uptake in gastric cancer varies according to the microsatellite instability (MSI) status.

METHODS

Consecutive gastric cancer patients who underwent PET/CT imaging and MSI analysis were included in the study. The maximum standardized uptake value (SUVmax) of gastric cancer was assessed using PET/CT imaging.

RESULTS

Of 131 gastric cancers, 16 exhibited a high incidence of MSI (MSI-H) and 3 exhibited a low incidence of MSI (MSI-L). In 29 subjects who showed no uptake on PET/CT imaging the gastric cancers were all microsatellite stable (MSS). Gastric cancers with MSI were related to age older than 60 years (p = 0.002), cancer volume larger than 10 cm(3) (p = 0.015), and the presence of FDG uptake on PET/CT imaging (p = 0.001). A higher SUVmax of gastric cancer was linked to the presence of MSI (p < 0.001).

CONCLUSION

The presence of MSI is related to FDG uptake in gastric cancer. Care should be taken with MSS gastric cancers, because they show lower SUVmax on PET/CT imaging than MSI gastric cancers.

α2-Adrenergic agonists including xylazine and dexmedetomidine inhibit norepinephrine transporter function in SK-N-SH cells

α2-Adrenergic agonists simulate norepinephrine (NE) action on α2 receptors of sympathetic neurons to mediate feedback inhibition of NE release. These agents are used as valuable adjuncts for management of hypertension and for anesthesia. Their action, equivalent to NE on α2 adrenergic receptors, raises the question whether α2 agonists may also target NE transporters (NETs), another major control mechanism for noradrenergic neurotransmission. We thus investigated the effect of α2 agonists on transport of the NE analog, (131)I-metaiodobenzylguanidine (MIBG). Results from this investigation showed that xylazine and dexmedetomidine dose-dependently blocked [(3)H]nisoxetine binding in neuron-like SK-N-SH cells. Furthermore, the agents acutely suppressed cellular MIBG uptake in a dose-dependent manner. This effect was uninfluenced by the α2 antagonist yohimbine, but was completely reversed by drug removal. There was no change in membrane NET density by the agents. Moreover, saturation analysis showed that xylazine and dexmedetomidine significantly increased Km without affecting Vmax, indicating competitive inhibition of MIBG transport. Thus, the α2 adrenergic agonists xylazine and dexmedetomidine, acutely suppress NET function through competitive inhibition of substrate transport, likely by direct interaction on a region that over-laps with the nisoxetine binding site.

Use of ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography in a miniature pig (Sus scrofa domestica) with pneumonia

A 1-y-old male miniature pig housed in our laboratory facility was evaluated for weight loss and rough coat condition. CBC results revealed neutrophilia. Radiography of the thoracic area showed increased opacity throughout the thoracic cavity except for the right caudal lobe. ¹⁸F-labeled fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET-CT) revealed elevated standard uptake values in the area corresponding to the radiologic findings. Follow-up thoracic radiography taken 2 wk after FDG-PET-CT showed several interval changes, including markedly decreased opacity throughout the entire thoracic cavity. Necropsy revealed adhesions between the upper portion of the caudal lobe of the left lung and thoracic wall. ELISA for several closely related infectious species confirmed the presence of antibody to Actinobacillus pleuropneumoniae serovar V.

MRI to differentiate benign from malignant soft-tissue tumours of the extremities: a simplified systematic imaging approach using depth, size and heterogeneity of signal intensity

OBJECTIVE

Differentiating between malignant and benign lesions on the basis of MR images depends on the experience of the radiologist. For non-experts, we aimed to develop a simplified systematic MRI approach that uses depth, size and heterogeneity on T(2) weighted MR images (T(2)WI) to differentiate between malignant and benign lesions, and evaluated its diagnostic accuracy.

METHODS

MR images of 266 patients with histologically proven soft-tissue tumours of the extremities (102 malignant, 164 benign) were analysed according to depth (superficial or deep), size (<50, ≥50 mm) and signal intensity (homogeneous or heterogeneous) on T(2)WI, to determine the ability of each to predict benign and malignant tumours. These three parameters were categorised into systematic combinations of different orders of application, and each combination was assessed for its ability to differentiate between benign and malignant lesions.

RESULTS

Univariate analysis showed that depth, size and heterogeneity on T(2)WI differed significantly between benign and malignant masses (p<0.0001 each). Multiple logistic regression analysis, however, showed that depth was not helpful in distinguishing benign from malignant lesions. The systematic combination of signal intensity, size and depth, in that order, was superior to other combinations, resulting in higher diagnostic values for malignancy, with a sensitivity of 64%, a specificity of 85%, a positive predictive value of 32%, a negative predictive value of 59% and an accuracy of 77%.

CONCLUSION

A simplified systematic imaging approach, in the order signal intensity, size and depth, would be a reference to distinguish between benign and malignant soft-tissue tumours for non-experts.

Effects of various anesthetic protocols on 18F-flurodeoxyglucose uptake into the brains and hearts of normal miniature pigs (Sus scrofa domestica)

This study used positron emission tomography-computed tomography (PET-CT) to evaluate the effects of 4 anesthetic protocols on 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) accumulation in the brains and hearts of miniature pigs (Sus scrofa domestica). The 18F-FDG standard uptake value was quantified by dividing the brain into 6 regions: cerebellum, brainstem, and frontal, parietal, temporal, and occipital lobes. Five (2 female and 3 male) clinically normal miniature pigs were premedicated with medetomidine (200 μg/kg IM) after which the following 4 anesthetic protocols were administered by using a crossover design: 1) propofol (4 mg/kg IV)-isoflurane inhalation; 2) propofol (4 mg/kg IV); 3) ketamine (5 mg/kg IV); 4) tiletamine-zolazepam (4.4 mg/kg IM). Compared with levels after other protocols, brain accumulation of 18F-FDG increased during propofol anesthesia but decreased with tiletamine-zolazepam. Relative to that due to other protocols, heart accumulation of 18F-FDG increased with propofol-isoflurane anesthesia but decreased with tiletamine-zolazepam. Comparing glucose accumulation in the brain and heart of miniature pigs by using PET-CT, we found that glucose accumulation varied according to the anesthetic protocol and between the 2 organs. These results can be used to evaluate how different anesthetic agents affect glucose metabolism in brain and heart of miniature pigs. Furthermore, these data should be considered when selecting an anesthetic agent for miniature pigs that will undergo PET-CT imaging with 18F-FDG.

Susceptibility-weighted imaging in patients with pyogenic brain abscesses at 1.5T: characteristics of the abscess capsule

BACKGROUND AND PURPOSE

SWI is a high-resolution 3D, fully velocity-compensated gradient-echo sequence that uses both magnitude and phase data. The purpose of this study was to investigate the phase behavior of the capsule of pyogenic brain abscesses with noncontrast SWI.

MATERIALS AND METHODS

Fourteen patients with pyogenic brain abscesses were studied at 1.5T. In all of the patients, SWI images were obtained and reviewed in addition to conventional MR images. Phase values within the abscess capsule were measured and compared with those from the abscess cavities and contralateral normal white matter using 1-way repeated measures ANOVA with post hoc Bonferroni analysis.

RESULTS

SWI phase images showed mild hypointesity in 6 patients, isointensity in 3 patients, and mixed iso- to mild hypointensity in 5 patients. The means of phase in the cavity, rim of abscesses, and contralateral normal white matter were -7.552 × 10(-3) ± 0.024, -0.105 ± 0.080, and +0.029 ± 0.011 radians, respectively. Post hoc comparisons showed significant differences between any pair of the 3 regions (abscess cavity, rim capsule, and normal white matter) in SWI (all Ps < .005).

CONCLUSIONS

SWI phase imaging shows evidence of paramagnetic substances in agreement with the presence of free radicals from phagocytosis. SWI may provide additional information valuable in the characterization of pyogenic brain abscesses.

Longitudinal split of the posterior cruciate ligament: description of a new MR finding and evaluation of its potential clinical significance

AIM

To evaluate the clinical significance of the intra-substance longitudinal split of the posterior cruciate ligament (LS-PCL) and to evaluate its potential clinical significance on MRI.

MATERIALS AND METHODS

The databases of two centres were searched for LS-PCL, 6917 knee magnetic resonance imaging (MRI) examinations undertaken were retrospectively reviewed. LS-PCL was defined as increased signal intensity in a PCL in the longitudinal direction, but with an intact ligament outer surface on MRI. Twelve patients were enrolled in this study. Available arthroscopic results, degree of posterior knee instability, and changes in MRI findings, or the degree of instability during follow-up (FU), were reviewed from the patients medical records and via their MRI images. MRI images were reviewed by two musculoskeletal radiologists in consensus for presence and location of LS-PCL and any combined injuries: menisci lesions, ligament injuries, and bone marrow changes.

RESULTS

Seven of 12 patients (58.3%) had morphological or functional evidence of PCL injury or insufficiency according to the change of posterior instability on FU stress testing (n=3), insufficiency during arthroscopy (n=2), or decreased extent and altered shape of the PCL split on the FU MRI (n=3). One patient revealed both change of posterior instability on FU stress testing and insufficiency during arthroscopy. Combined injuries were revealed in seven patients. Five patients had isolated LS-PCL: two patients underwent arthroscopic PCL reconstructions; and another three patients revealed knee instability on stress testing.

CONCLUSION

Although LS-PCL has not been described before, it can be a type of partial tear of the PCL, which causes PCL insufficiency.

Mistaken diagnosis of optic neuritis and the possible role of phosphodiasterase-5 inhibitors (Sildenafil/Viagra)

The diagnosis of optic neuritis and particularly retrobulbar optic neuritis when atypical and not responsive to corticosteroid treatment may need to be revised. This is now especially so in male patients who should be questioned regarding their taking a phosphodiasterase-5 inhibitor in particular Viagra. The case history of such a patient is presented who sustained posterior ischaemic optic neuropathy mistaken for retrobulbar neuritis resulting in bilateral severe visual loss.

Myocardial perfusion imaging using adenosine-induced stress dual-energy computed tomography of the heart: comparison with cardiac magnetic resonance imaging and conventional coronary angiography

OBJECTIVE

To evaluate the feasibility and diagnostic accuracy of adenosine-stress dual-energy computed tomography (DECT) for detecting haemodynamically significant stenosis causing reversible myocardial perfusion defect (PD) compared with stress perfusion magnetic resonance imaging (SP-MRI) and conventional coronary angiography (CCA).

METHODS

Fifty patients with known coronary artery disease (CAD) detected by dual-source CT (DSCT) were investigated by contrast-enhanced, stress DECT with high- and low-energy x-ray spectra settings during adenosine infusion. A colour-coded iodine map was used for evaluation of myocardial PDs compared with rest DSCT perfusion images. Reversible myocardial PDs according to the stress DECT/rest DSCT were compared with SP-MRI on a segmental basis and CCA on a vascular territorial basis.

RESULTS

A total of 697 myocardial segments and 123 vascular territories of 41 patients were analysed. Three hundred one segments and 72 vascular territories in 38 patients showed reversible PDs on stress DECT. Stress DECT had 89% sensitivity, 78% specificity and 82% accuracy for detecting segments with reversible PDs seen on SP-MRI (n=28). Compared with CCA (n=41), stress DECT had 89% sensitivity, 76% specificity and 83% accuracy for the detection of vascular territories with reversible myocardial PDs that had haemodynamically relevant CAD.

CONCLUSION

Adenosine stress DECT can identify stress-induced myocardial PD in patients with CAD.

Poly-epsilon-caprolactone/gel hybrid scaffolds for cartilage tissue engineering

The aim of this study was to determine the suitability of hybrid scaffolds composed of naturally derived biopolymer gels and macroporous poly-epsilon-caprolactone (PCL) scaffolds for neocartilage formation in vitro. Rabbit articular chondrocytes were seeded into PCL/HA (1 wt % hyaluronan), PCL/CS (0.5 wt % chitosan), PCL/F (1:3 fibrin sealant plus aprotinin), and PCL/COL1 (0.24% type I collagen) hybrids and cultured statically for up to 50 days. Growth characteristics were evaluated by histological analysis, scanning electron microscopy, and confocal laser scanning microscopy. Neocartilage was quantified using a dimethyl-methylene blue assay for sulfated glycosaminoglycans (sGAG) and an enzyme-linked immunosorbent assay for type II collagen (COL2), normalized to dsDNA content by fluorescent PicoGreen assay. Chondrocytes were homogenously distributed throughout the entire scaffold and exhibited a predominantly spheroidal shape 1 h after being seeded into scaffolds. Immunofluorescence depicted expanding proteoglycan deposition with time. The sGAG per dsDNA increased in all hybrids between days 25 and 50. PCL/HA scaffolds consistently promoted highest yields. In contrast, total sGAG and total COL2 decreased in all hybrids except PCL/CS, which favored increasing values and a significantly higher total COL2 at day 50. Overall, dsDNA content decreased significantly with time, and particularly between days 3 and 6. The PCL/HA hybrid displayed two proliferation peaks at days 3 and 25, and PCL/COL1 displayed one proliferation peak at day 12. The developed hybrids provided distinct short-term environments for implanted chondrocytes, with not all of them being explicitly beneficial (PCL/F, PCL/COL1). The PCL/HA and PCL/CS hybrids, however, promoted specific neocartilage formation and initial cell retention and are thus promising for cartilage tissue engineering.

Imaging diagnosis--FDG-PET/CT of a canine splenic plasma cell tumor

An 8-year-old Shih Tzu developed abdominal pain and hyperglobulinemia. A round splenic mass was noted radiographically and sonographically. The patient was evaluated by fluorodeoxyglucose positron emission tomography coupled with computed tomography (FDG-PET/CT). There was no evidence of metastasis or bone marrow involvement on PET/CT images. The standardized uptake value (SUV) of the splenic mass was increased over the reference range (SUV = 4.83). The patient was diagnosed as splenic extramedullary plasmacytoma through immunohistopathologic study. After the splenectomy, the globulin level normalized and the patient is alive without complications.

High FDG uptake in PET/CT predicts worse prognosis in patients with metastatic gastric adenocarcinoma

PURPOSE

We evaluated the role of FDG-PET/CT in patients with metastatic gastric adenocarcinoma before palliative chemotherapy to predict prognosis and chemotherapeutic response.

METHODS

The study included 35 consecutive newly diagnosed patients with metastatic gastric adenocarcinoma who underwent FDG-PET/CT before palliative chemotherapy. Maximum standardized uptake value (SUVmax) of the primary tumor was assessed to evaluate survival and chemotherapeutic response. Survival analysis was performed for time to progression and overall survival using the Kaplan-Meier method. Cox proportional hazard models were used to determine independent prognostic factors.

RESULTS

All primary tumors were visualized using FDG-PET/CT (mean SUVmax = 8.1 ± 4.5, range 2.5-22.1). Sensitivity, specificity, and accuracy of FDG-PET/CT in detection of solid organ metastasis were 95.2% (20/21), 100% (14/14), and 97.1% (34/35), respectively. No significant difference of primary tumor SUVmax was found among the chemotherapeutic response groups. Univariate survival analysis demonstrated ECOG performance status (≥2), presence of solid organ metastasis, number of organs involved in distant metastasis (≥2), and SUVmax of the primary tumor (>8) as significant predictors for poor overall survival. Multivariate survival analysis showed SUVmax of the primary tumor (P = 0.048), presence of solid organ metastasis (P = 0.015), and ECOG performance status (P = 0.002) as significant independent prognostic predictors for overall survival.

CONCLUSIONS

High FDG uptake of the primary tumor in patients with metastatic gastric adenocarcinoma is associated with poor overall survival. Assessment of tumor FDG uptake has limited value for prediction of chemotherapeutic response, but provides useful information regarding prognosis.

Hepatic metastases of gastric adenocarcinoma showing metabolic remission on FDG-PET despite an increase in size on CT

We report a gastric adenocarcinoma patient with liver metastases. The metastases showed progression on computed tomography (CT), but this was not true progression in terms of metabolic activity according to (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET). Discordance between size criteria and metabolic criteria has been reported in liver gastrointestinal stromal tumors, hepatomas, and renal cell carcinomas after dramatic responses with targeted therapies such as imatinib, sorafenib, and sunitinib (1-6). However, this discordance has been rarely reported in liver metastases of gastric adenocarcinoma when treated with conventional chemotherapy.