Brain plasticity after rehabilitation in a severe case of artery of Percheron stroke assessed with multimodal MR imaging

Artery of Percheron (AOP) stroke is a rare event. We describe an AOP stroke involving both thalami and the midbrain, resulting in a multifunctional clinical impairment. Intensive inpatient multidisciplinary rehabilitation favored the recovery of motor deficits, together with the improvement of cognitive dysfunctions. MRI assessment in the chronic post-stroke phase showed structural and functional reorganization in response to the extended thalamic tissue damage and absence of revascularization. Thalamo-cortical networks involving frontal and prefrontal regions, as well as parietal areas were disrupted, whereas increased functional thalamo-occipital connectivity was found. This report sheds light on brain reorganization following AOP stroke after rehabilitation..

Individual Thresholding of Voxel-based Functional Connectivity Maps. Estimation of Random Errors by Means of Surrogate Time Series

INTRODUCTION

This article is part of the Focus Theme of Methods of Information in Medicine on "Biosignal Interpretation: Advanced Methods for Neural Signals and Images".

BACKGROUND

Voxel-based functional connectivity analysis is a common method for resting state fMRI data. However, correlations between the seed and other brain voxels are corrupted by random estimate errors yielding false connections within the functional connectivity map (FCmap). These errors must be taken into account for a correct interpretation of single-subject results.

OBJECTIVES

We estimated the statistical range of random errors and propose two methods for an individual setting of correlation threshold for FCmaps.

METHODS

We assessed the amount of random errors by means of surrogate time series and described its distribution within the brain. On the basis of these results, the FCmaps of the posterior cingulate cortex (PCC) from 15 healthy subjects were thresholded with two innovative methods: the first one consisted in the computation of a unique (global) threshold value to be applied to all brain voxels, while the second method is to set a different (local) threshold of each voxel of the FCmap.

RESULTS

The distribution of random errors within the brain was observed to be homogeneous and, after thresholding with both methods, the default mode network areas were well identifiable. The two methods yielded similar results, however the application of a global threshold to all brain voxels requires a reduced computational load. The inter-subject variability of the global threshold was observed to be very low and not correlated with age. Global threshold values are also almost independent from the number of surrogates used for their computation, so the analyses can be optimized using a reduced number of surrogate time series.

CONCLUSIONS

We demonstrated the efficacy of FCmaps thresholding based on random error estimation. This method can be used for a reliable single-subject analysis and could also be applied in clinical setting, to compute individual measures of disease progression or quantitative response to pharmacological or rehabilitation treatments.

Atlas-based vs. individual-based deterministic tractography of corpus callosum in multiple sclerosis

Diffusion tensor (DT) magnetic resonance imaging is able to quantify tissue microstructure properties and to detect pathological changes even in the normal appearing tissues. DT sequence parameters which provide optimal SNR and minimum acquisition time, and an individual-based tractography post-processing allowed corpus callosum tractography even in multiple sclerosis (MS) patients also with no need of a-priori atlas. In this preliminary study, we were able to obtain reliable individual-based tractography in 28/30 MS patients. DT-derived indices computed in tracks obtained with individual-based tractography were able to differentiate healthy volunteers from MS patients better than the same indices computed with the atlas method. This indicates that such an optimized sequence may be a reliable tool to be used in future MS studies.

A worldwide analysis of ISO 9000 standard diffusion

Purpose

To provide a cross‐section of International Standardization Organization (ISO) 9000 quality certification diffusion over time and its impact on industrial systems.

Design/methodology/approach

The starting point of the analysis is “The ISO survey of ISO 9000 and ISO 14001 certificates” document. Available data concur to trace a synthesis of what has happened and what is in process all over the world. Five main aspects are discussed: the correspondence between ISO 9000 standards and total quality management strategy; the effects of ISO 9000 certification on business performance; the ISO 9000 certificates diffusion in the world; the comparison between economical and entrepreneurial structure of different countries and certificates diffusion; the proposal of a prediction model for the diffusion of ISO 9000 certificates.

Findings

The evolution curve of the number of certificates over time in each country presents a “saturation effect.” This behavior has been analyzed by a diffusion forecasting model. The analysis of regional share certificates evolution evidences a sensible increase of Far East countries. The analysis of ISO 9000 certificates' share by industrial sector highlights a growth for the most sectors; only a few of them show a negative trend in last two years. A relationship between ISO 9000 certificates and socio‐economic indicators of a country (human development index, gross national product) has been individuated.

Practical implications

The stunning growth of ISO 9000 certifications all over the world confirms a strong polarization of enterprises' interest in this practice. Looking at the empirical data, some questions come out about the future. Will the certification market go on? Will certified enterprises continue to be interested to the certification process?

Originality/value

This paper analyzes the worldwide evolution of ISO 9000 certification and suggests a new prediction model for the diffusion of ISO 9000 certificates.

Ultrasound-guided laser thermal ablation for parathyroid adenomas: analysis of three cases with a three-year follow-up

BACKGROUND

In patients with primary hyperparathyroidism (pHPT) the therapeutical choice is surgery. In patients with high surgical and anesthetic risks, ultrasound-guided laser ablation (LTA) of parathyroid adenoma has been reported to reduce parathyroid hormone (PTH) hypersecretion without relevant side effects. No data are available from patients followed for >6 months. We report our 3-year follow-up experience with LTA in 3 patients affected by pHPT due to a parathyroid tumor.

METHODS

LTA was performed under color-Doppler ultrasound guidance with a continuous pulse at 2 W (total treatment duration: 300 s in each session; total energy: 1,200 J in two sessions).

RESULTS

In the first patient who refused to undergo the second LTA session, calcium, PTH levels and parathyroid lesion volume showed a slight reduction, returning to baseline values in a month. In the second patient, no modification of parathyroid lesion was obtained even if calcium levels temporarily normalized. In the third patient, LTA led to normalization of calcium and PTH levels and to a 99% reduction of parathyroid volume.

CONCLUSION

After LTA procedures the long-term disease remission of pHPT is achievable in a minority of patients. Data from larger samples are needed to verify the usefulness of this procedure.

Small hyperechogenic nodules in thyroiditis: usefulness of cytological characterization

Small hyperechogenic nodules occurring in thyroiditis frequently raise the question of their nature requiring additional evaluation. Given the scarcity of the studies addressing this issue, we have investigated whether cytopathological analysis of fine needle aspirates (FNA) of these lesions may be of diagnostic relevance. In this preliminary study, we submitted to cytopathological analysis 10 nodular lesions as well as the normal counter-lateral tissue. In none but one of the cases analyzed, the cytopathology was able to detect differences between the hyperechogenic models and the hypoechogenic parenchyma suggesting that these lesions bear no-clinical relevance. Therefore, FNA of these nodules is not advisable and should be limited to those with defined at risk clinical features.

Elastofibroma dorsi: ultrasound pattern in three patients

Elastofibroma dorsi is a rare benign tumor with a prevalence in the female population. The tumor is composed of adipose and fibrous tissue. It is typically localized at the tip of the scapular and is more frequently bilateral. Even if there are only very few reports on this topic, the incidence of the tumor seems to be less rare than expected. Elastofibroma dorsi was identified in 1961 and the first study using diagnostic ultrasound technique was published in 1996, however, since then no other major work has been produced. The purpose of the paper is to present three cases of elastofibroma dorsi, all studied by ultrasound imaging, including color and power Doppler, and by fine needle aspiration biopsy. Furthermore, in one case i.v. contrast media (Levovist) was used, and in two cases a CT and MRI evaluation was also made. Surgical excision was not performed in any of the cases. The relevant follow up was performed by clinical and ultrasound tests. In all the cases the ultrasound pattern of the elastofibroma dorsi was very similar to the surrounding muscular tissue, and neither a clear cleavage surface nor a specific vascular pattern could be evidenced. The tumor was very difficult to define from the surrounding tissue, except for a more evident coarse pattern and the same happened for the CT and MR, where a layered pattern of fatty tissue was noted. In this small cohort the tumor was mainly monolateral. The ultrasound investigation, integrated with color and power Doppler permitted a correct diagnosis, which was confirmed by the fine needle biopsy. Therefore, the less expensive ultrasound diagnosis, as a major method of screening for elastofibroma dorsi, would seem to be a reasonable proposal.

Our experience in transrectal ultrasonography and biopsy in carcinoma of the prostate

The Authors present a short review of the literature comparing transrectal ultrasound of the prostate (TRUS) and ultrasound guided biopsy and the results of 694 consecutive prostatic biopsies from their cohort. All the biopsies were US guided with an endorectal biplanar 5 MHz probe and transperineal samples were carried out with an 18 G needle (cutting length 22 mm) over the last 4 years. The histological exam showed 187 prostates affected by cancer while 112 had only inflammation. The operator's opinion, based on ultrasonography and integrated with a digital rectal exam (DRE) and a prostate specific antigen (PSA) blood test, was correct in 80% of the cases, with 90% sensitivity and 70% specificity. The positive prediction rate was 74% and the negative prediction rate was 89%.

Laser thermal ablation in the treatment of small hepatocellular carcinoma: results in 74 patients

PURPOSE

To evaluate the safety, local effectiveness, and long-term results of laser thermal ablation (LTA) in the treatment of small hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Ninety-two biopsies proved small HCCs (range, 0.8-4.0 cm) in 74 patients who were treated percutaneously with LTA in an outpatient clinic. A laser at a power of 5.0 W was coupled with one to four fibers that were advanced through 21-gauge needle(s) for 6-12 minutes. All lesions were evaluated with computed tomography (CT) for changes in size and vascular pattern, recurrence rates, and cumulative survival rates. Patients were examined for complications.

RESULTS

No major complications occurred in 117 LTA sessions, with an average of 1.3 sessions per tumor. At 3 months, CT scans showed a nonenhancing area (complete necrosis) in 89 (97%) of 92 lesions. During follow-up (range, 6-66 months; mean, 25.3 months), 84 tumors (91%) decreased in size. The local recurrence rates (range, 1-5 years) ranged from 1.6% to 6.0%. Recurrence rates (range, 12-60 months) in other liver segments ranged from 24% to 73%. Cancer-free survival rates (range, 1-4 years) ranged from 73% to 24%. Overall survival rates were 99%, 68%, and 15% at 1, 3, and 5 years, respectively. Twenty-one patients (28%) died.

CONCLUSION

LTA is a safe and effective treatment for small HCC.

Hepatocellular Carcinoma: Long-term Results of Combined Treatment with Laser Thermal Ablation and Transcatheter Arterial Chemoembolization

PURPOSE

To determine the potential long-term effectiveness of laser thermal ablation (LTA) followed by transcatheter arterial chemoembolization (TACE) in the percutaneous ablation of large hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Thirty large HCCs 3.5-9.6 cm in diameter (mean diameter, 5.2 cm) and 15 small HCCs 0.8-3.0 cm (mean diameter, 1.9 cm) were treated with ultrasonographically guided LTA with TACE and with LTA alone, respectively, in 30 patients: 19 with a solitary large HCC, and 11 with one to three additional synchronous small HCCS: A 1.064-microm neodymium yttrium-aluminium-garnet (Nd-YAG) laser at a power of 5.0 W was coupled with one to four quartz optic fibers that were advanced through 21-gauge needles. Segmental TACE was performed 30-90 days after LTA. All lesions were evaluated for change in size at computed tomography (CT), alpha-fetoprotein (AFP) levels, recurrence rates, and cumulative survival rates.

RESULTS

No major complications occurred in 127 LTA sessions. CT showed complete tumor necrosis in 27 (90%) of 30 large HCCS: Twenty-eight patients were followed up for 6-41 months (mean, 17.1 months). In 25 patients, all lesions appeared stable or smaller at CT. AFP levels decreased to the normal range in all patients with high pretreatment values. The 1-, 2-, and 3-year local recurrence rate was 7% in large HCCS: Complete tumor necrosis was achieved in all 15 (100%) small HCCs; none of them recurred locally. The 1-, 2-, and 3-year cumulative survival rates were 92%, 68%, and 40%, respectively.

CONCLUSION

LTA followed by TACE is an effective palliative therapy in treating large HCCS:

[Non-cardiac transcatheter intervention: operative possibilities in a hemodynamics laboratory]

INTRODUCTION

New possibilities for transcatheter treatment of the cardiovascular system are guaranteed with the improvement of materials and the availability of new devices. Nevertheless, a rationalization of the potential activity in this sector seems to be necessary, and it could arise through the presence of Catheterization Laboratories "open" to diagnostic procedures and therapy that are not confined to the coronary system. This clinical study reports the experiences and results of our work in this field.

MATERIALS AND METHODS

During the period from May 1995 to May 1997, our laboratory performed 205 diagnostic procedures that did not involve the coronary system. Based on this diagnostic work, there emerged 91 cases with an indication for transcatheter intervention, which was subsequently performed at our laboratory. There were 68 peripheral angioplasty procedures on the iliofemoral axis, 2 angioplasties of the subclavian artery, 8 of the renal artery, 2 procedures involving the treatment of A-V fistulas, one case of femoral pseudoaneurysm treatment and 10 cases of transcutaneous pericardiotomy performed with a balloon catheter. All the procedures were performed by our laboratory staff using materials that are normally at our disposal.

RESULTS

Successful results were obtained in 65 out of the 68 peripheral angioplasty procedures and in all of the 8 renal and 2 subclavian angioplasties. The positioning of the endoprosthesis for the closure of the A/V fistula was effective in one of the two cases. The transcatheter treatment of the femoral pseudoaneurysm was successful. In all cases where a pericardiotomy was performed with a balloon catheter, there was no reoccurrence of cardiac tamponade during the follow-up period. No complications were noted as a result of any of the procedures.

CONCLUSIONS

Our experience documents how it is possible to increase the diagnostic and therapeutic options in a Catheterization Laboratory. However, willingness on the part of the staff to update their skills continually and collaborate with other specialists is necessary in order to maintain optimal operative standards.

[The interstitial photocoagulation with laser light of liver tumors]

INTRODUCTION

Interstitial laser photocoagulation (ILP) is a recent interventional procedure performed under US or CT guidance which is capable of inducing thermal necrosis in solid tumors. We have used this technique for about 2 years to treat primary and secondary liver cancers.

MATERIALS AND METHODS

Thirty-five patients, 20 of them with liver metastases and 15 with HCC, have been examined: 59 lesions in all, ranging in diameter 10 to 65 mm. Forty-nine lesions have been followed-up for at least 2 months and 25 for at least 6 months. The treatment was performed positioning one to six (18-21 G) modified Chiba needles in the lesions to be treated, according to their sizes, under US or CT guidance. The optical fibers (400-800 mu) were then inserted and the Laser was fired to administer 1,000 Joule/session, with 5-10 W power range. The US and CT patterns of the ILP-treated lesions are reported.

RESULTS

Dynamic CT examinations 2 months after treatment showed complete tumor destruction in 77.5% of the lesions. The best results were obtained in the lesions < 3 cm phi; in particular, 32/38 lesions (84.2%) < 3 cm and with at least 2 months' follow-up exhibited complete necrosis, as did 6 of 11 lesions (54.6%) over 3 cm phi. When residual tumor tissue was demonstrated, further ILP sessions were useless. We observed only few complications which resolved spontaneously in all cases.

CONCLUSIONS

At present, ILP remains an experimental procedure: further studies on larger series of patients and comparison with the results of other interventional procedures are needed to confirm its efficacy in treating primary and secondary liver cancers.

[Magnetic resonance in trigeminal neuralgia]

One of the possible causes of the so-called "essential" trigeminal neuralgia is a neurovascular compression of the fifth cranial nerve root at the pons. The demonstration of this hypothesis could orientate the surgical treatment to microvascular decompression. In order to evaluate the role of MRI in the diagnosis of trigeminal neuralgia due to neurovascular compression, the authors present the results of a prospective evaluation of the cranial MR studies of 18 neuralgic patients in comparison with a retrospective evaluation of the cranial MR studies of 50 healthy control subjects. The results show that neurovascular compression can be demonstrated in 83.3% of the neurological patients. In all cases a good correlation between the clinical symptoms, the side of positive MR findings and the surgical findings, when available, was demonstrated. On the other hand, neurovascular compression was demonstrated in 28% of the healthy control subjects. The authors conclude that neurovascular compression can be demonstrated in a high percentage of patients with the so-called "essential" trigeminal neuralgia. Compared with the other imaging modalities (angiography, Computed Tomography) MRI is the best technique in the diagnosis of this disease. In fact, MRI is not only able to differentiate the symptomatic from the essential type of neuralgia, but is also very sensitive in the identification of trigeminal neuralgia due to neurovascular compression. This diagnosis could direct the surgical treatment to microvascular decompression.

[The imaging diagnosis of hepatic focal nodular hyperplasia]

Focal nodular hyperplasia (FNH) is a rare benign hepatocellular tumor occurring in noncirrhotic patients, mostly females, 20-50 years of age. It is usually asymptomatic. The authors took the lead from 5 cases of FNH studied over last year to analyze the different patterns exhibited by the condition on the various imaging techniques currently available. At scintigraphy with 99mTc DISIDA or with TcSC, FNH can be hyper, normal, or hypocaptating. On US scans, the lesion is often homogeneous and isoechoic, but it can also be hyper/hypoechoic. With Doppler US, high-flow signals can be observed. On unenhanced CT scans the lesion is solid, well-demarcated, isodense or slightly hyperdense; sometimes it shows a central hypodense area corresponding to fibrovascular scar. On postcontrast scans it appears hyper/isodense. At dynamic CT the lesion density, which is high during the arterial phase, decreases quickly in the parenchymal and the venous phases and reaches equal/inferior values to surrounding liver parenchyma. On liver angio-CT it is sometimes possible to visualize the bile ducts in the central scar. At angiography, FNH is hypervascular and homogeneous. On MR scans, in T1-weighted SE sequences, the condition is isointense or slightly hypointense, whereas on T2-weighted pulse sequences it is slightly hyperintense; the central scar is hypointense on T1, and hyperintense on T2, weighted scans. As we have no pathognomonic patterns but only orientative ones, a reliable differential diagnosis with hepatocellular adenoma (HA) and fibrolamellar hepatocellular carcinoma (FL-HCC) must be based on biopsy or cytology or, even better, histology. The differential diagnosis is nevertheless necessary because, while FNH does not usually require a surgical approach but only a radiological follow-up, both HA (due to possible bleeding and degeneration) and FL-HCC require surgery.