Cervical facet oedema: prevalence, correlation to symptoms, and follow-up imaging.

AIM: To evaluate the prevalence of cervical facet oedema in patients referred for magnetic resonance imaging (MRI) to investigate neck pain and/or radiculopathy, and to investigate whether there is a correlation between the presence of oedema and patients' symptoms. MATERIALS AND METHODS: A retrospective report review of 1885 patients undergoing cervical spine MRI between July 2008 and June 2015 was performed. Exclusion criteria included acute trauma, surgery, neoplastic disease, or infection in the cervical spine. One hundred and seventy-three MRI studies with cervical facet oedema were evaluated by each of the two radiologists. In these patients, the grade of bone marrow oedema (BMO) and corresponding neuroforaminal narrowing at the cervical facets was assessed. Correlation with symptoms was performed based on pre-MRI questionnaire. RESULTS: The prevalence of cervical facet oedema was 9%; the most commonly affected levels were C3-4, C4-5, and C2-3. A total of 202 cervical facets were evaluated: mild BMO was seen in 35%, moderate in 41%, and severe in 24% of cases. Surrounding soft-tissue oedema was observed in 36%, 69%, and 92% of the BMO grades, respectively. The correlations between unilateral radiculopathy and ipsilateral facet BMO grades were 79%, 83%, and 73% (chi-square, p<0.001), respectively. Furthermore, neuroforaminal narrowing on the corresponding level was found in 35%, 38%, and 11% of cases, respectively. At follow-up imaging, facet oedema was most likely to remain unchanged or to decrease. CONCLUSION: The prevalence of cervical facet oedema is 9%. Cervical facet oedema is associated with ipsilateral radiculopathy. Neuroforaminal narrowing, however, is not associated with facet oedema.

Three-dimensional magnetic resonance imaging analysis of hip morphology in the assessment of femoral acetabular impingement.

AIM: To determine a possible association between femoral-acetabular impingement (FAI) volume and the development of labral tear using a three-dimensional (3D) model reconstruction of the acetabulum and the femoral head. MATERIALS AND METHODS: Magnetic resonance arthrography images of the hip in 42 patients with pain and suspected labral tear were acquired using a 1.5T MRI machine. Using 3D analysis software, outlines of the acetabular cup and femoral head were drawn and 3D reconstruction obtained. To control for differences in patient size, ratios of acetabulum : femoral head volume (AFV) and acetabulum : femoral head surface area (AFA) were used for analysis. The association between volume of acetabulum : femoral head and FAI was investigated using ANOVA analysis. RESULTS: There were 19 men and 23 women with a mean age of 39 years (range 18-78 years). The average AFV was 0.64 (range 0.37-1.05, SD 0.16) and AFA was 0.73 (range 0.36-1.26, SD 0.23). Herniation pit was significantly associated with a small AFV. CONCLUSION: Femoral neck herniation pits are associated with a low AFV. Gross volume and surface area ratios do not appear to correlate with labral tears or cartilage loss. This technique will enable more advanced analysis of morphological variations associated with FAI.

Remote postconditioning is more potent than classic postconditioning in reducing the infarct size in anesthetized rabbits.

PURPOSE: Postconditioning confers protection to the heart after a potentially lethal episode of prolonged ischemia. There is evidence that it may also be protective when applied at a distal artery. In the present study, we sought to determine whether remote postconditioning within the heart (local) or outside the heart (distal) is effective in salvaging the ischemic heart in vivo and to compare its effect with that of the classic postconditioning. METHODS: Twenty seven open chest New Zealand white anesthetized male rabbits were divided into four groups and were exposed to 30 min regional myocardial ischemia (isc), after ligation of a prominent coronary artery, followed by 3 h reperfusion (rep) after releasing the snare. Control group (n = 7) was subjected to no additional interventions, postC group (n = 6) was subjected to four cycles of 1 min isc/1 min rep of the same coronary artery at the beginning of reperfusion, remote local postC group (n = 7) to four cycles of 1 min isc/1 min rep of another coronary artery 30 s before the end of index isc and remote distal postC group (n = 7) to four cycles of 1 min isc/1 min rep of another (carotid) artery again 30 s before the end of index isc. Infarct size (I) and area at risk (R) were delineated with the aid of TTC staining and green fluorescent microspheres respectively and their ratio was expressed in percent (%I/R). RESULTS: Remote local and remote distal postC reduced the % I/R ratio (17.7 +/- 1.7% and 18.4 +/- 1.6%, respectively vs 47.0 +/- 2.5% in the control group, P < 0.01). Classic PostC had an intermediate protective effect (33.1 +/- 1.7%, P < 0.05 vs all the other groups). CONCLUSION: Remote postconditioning consisted of 1 min isc/1 min rep protects the ischemic rabbit heart in vivo, independently of the site of the remote artery. This intervention seems to confer a stronger protection than the classic postconditioning.

MRI of injuries to the first interosseous cuneometatarsal (Lisfranc) ligament.

OBJECTIVE: The objective of this study was to assess the utility of MRI in diagnosing injury to the first interosseous cuneometatarsal (Lisfranc) ligament and to additionally determine the associated patterns of traumatic soft tissue and osseous injury. MATERIALS AND METHODS: Fifteen patients (16 feet) who were referred for MRI evaluation of the Lisfranc ligament, and had operative exploration or examination under anesthesia, were included for analysis. Standard non-contrast MRI foot imaging was performed in all cases. Evaluation of the following components was performed: the dorsal and plantar bundles of the Lisfranc ligament, the plantar tarsal metatarsal ligaments, soft tissue edema and fluid, and bone marrow edema and fractures. Surgical reports were regarded as the reference standard in all cases. RESULTS: Seven of 10 cases of grade 3 Lisfranc ligament injuries at surgery were correctly graded at MRI. No cases of surgically proven complete Lisfranc ligament tears (grade 3) were interpreted as normal at MRI. All Lisfranc ligament sprains (grade 2 or 3) at surgery were detected at MRI. Two of six cases reported as grade 1 injuries at MRI were normal at surgery. No cases of surgically proven normal or sprained Lisfranc ligaments were interpreted as grade 3 tears on MRI. Four of six of our cases of normal or sprained Lisfranc ligaments demonstrated fractures; while the minority of complete Lisfranc ligament tears (3/10) contained fractures. CONCLUSION: MRI is reasonably accurate at detecting traumatic injury to the Lisfranc ligament. However, in clinically suspected cases of traumatic Lisfranc ligament injury, true positive rate for sprain is low.

MRI of rupture of the spring ligament complex with talo-cuboid impaction.

The spring ligament complex is essential for the stability of the longitudinal arch of the foot and includes the ligaments between the calcaneus and the talus at the superomedial to inferoplantar aspect of the foot. Tears of the spring ligament complex are most commonly degenerative in etiology and secondary to concomitant abnormality of the posterior tibial tendon. We report MRI findings in a 30-year-old man who presented with traumatic rupture of the spring ligament complex, seen following dislocation of the talonavicular joint. We also describe the previously unreported MRI features of talo-cuboid impaction secondary to disruption of the spring ligament complex.

Use of a novel percutaneous biopsy localization device: initial musculoskeletal experience.

OBJECTIVE: To preliminarily evaluate a new CT-biopsy guidance device, the SeeStar (Radi, Uppsala, Sweden), for use in musculoskeletal applications. DESIGN: The device was evaluated using an imaging phantom and in various simulated clinical biopsy situations. The phantom study was undertaken to optimize the linear metallic artifacts produced by the guidance device. The phantom and guidance device were imaged with CT after altering different imaging parameters, including field of view, filter, focal spot size, kV, mAs, slice thickness and pitch. Clinical biopsy situations were simulated for a superficial biopsy, a deep biopsy and a horizontal biopsy approach. RESULTS: Altering CT parameters had little effect on the subjective appearance of the linear metal artifact, which is used to plan the biopsy approach. Placement of an 18-G needle inside of the biopsy device was subjectively helpful in exaggerating the artifact. Use of this artifact could be helpful in planning biopsy approach for deep lesions or lesions near critical structures. The metal guide on the device adequately supports a standard biopsy needle, making it potentially advantageous for biopsy of superficial lesions and lesions approached from a horizontal orientation. CONCLUSION: Use of this CT-biopsy guidance device is potentially useful for musculoskeletal applications. The linear metal artifact produced by the device can help plan the biopsy approach. The device can also be useful in biopsy situations where the biopsy needle requires external support during imaging.

Synthesis, binding studies and in vivo biological evaluation of novel non-peptide antihypertensive analogues.

AT(1) antagonists (SARTANs) constitute the last generation of drugs for the treatment of hypertension, designed and synthesized to mimic the C-terminal segment of the vasoconstrictive hormone angiotensin II (AngII). They exert their action by blocking the binding of AngII on the AT(1) receptor. Up to date eight AT(1) antagonists have been approved for the regulation of high blood pressure. Although these molecules share common structural features and are designed to act under the same mechanism, they have differences in their pharmacological profiles and antihypertensive efficacy. Thus, there is still a need for novel analogues with better pharmacological and financial profiles. An example of a novel synthetic non peptide AT(1) antagonist which devoids the classical template of SARTANs is MM1. In vivo studies showed that MMK molecules, which fall in the same class of MM1, had a significant antihypertensive (40-80% compared to the drug losartan) activity. However, in vitro affinity studies showed that losartan has considerably higher affinity. The theoretical docking studies showed that MM1 acts on the same site of the receptor as losartan. They exert hydrophobic interactions with amino acid Val108 of the third helix of the AT(1) receptor and other hydrophobic amino acids in spatial vicinity. In addition, losartan favours multiple hydrogen bondings between its tetrazole group with Lys199. These additional interactions may in part explain its higher in vitro binding affinity.

Conformation and bioactivity. Design and discovery of novel antihypertensive drugs.

Peptidomimitism is applied to the medicinal chemistry in order to synthesize drugs that devoid of the disadvantages of peptides. AT1 antagonists constitute a new generation of drugs for the treatment of hypertension designed and synthesized to mimic the C-terminal segment of Angiotensin II and to block its binding action on AT1 receptor. An effort was made to understand the molecular basis of hypertension by studying the conformational analysis of Ang II and its derivatives as well as the AT1 antagonists belonging to SARTANs class of molecules. Such studies offer the possibility to reveal the stereoelectronic factors responsible for bioactivity of AT1 antagonists and to design and synthesize new analogs. An example will be given which proves that drugs with better pharmacological and financial profiles may arise based on this rational design.

Efforts to understand the molecular basis of hypertension through drug:membrane interactions.

Biological membranes play an essential role in the drug action. They constitute the first barrier for drugs to exert their biological action. AT1 antagonists are amphiphilic molecules and are hypothesized to act on AT1 receptor through incorporation (first step) and lateral diffusion through membrane bilayers (second step). Various biophysical methods along with Molecular Modelling were applied in order to explore the plausible two step proposed mechanism of action for this class of antihypertensive drugs.

Design and synthesis of novel antihypertensive drugs.

AT1 antagonists constitute a new generation of drugs for the treatment of hypertension and are designed and synthesized to mimic the C-terminal segment of Angiotensin II (Ang II) and to block its binding action on AT1 receptor. For this reason, the conformational analysis of Ang II and its derivatives as well as the AT1 antagonists belonging to SARTANs class of molecules were studied. Such studies offer the possibility to reveal the stereoelectronic factors responsible for bioactivity of AT1 antagonists and to design and synthesize new analogues with better pharmacological and financial profiles. An example of a novel synthetic non-peptide molecule is given which mimics the His(6)-Pro(7)-Phe(8) part of Ang II and is based on the (S)-pyroglutamic acid.

Conformational and biological studies for a pair of novel synthetic AT1 antagonists: stereoelectronic requirements for antihypertensive efficacy.

One of the major systems which interferes with the disease of hypertension, is the Renin Angiotensin Aldosterone System (RAS). The octapeptide hormone angiotensin II is the active product of RAS which causes vasoconstriction when binds to the AT(1) receptor. In the last years, there has been a development of drugs which block the Angiotensin II from binding the AT(1) receptor and are called AT(1) antagonists. In an effort to comprehend their stereoelectronic features, a study has been initiated to compare the conformational properties of drugs already marketed for the treatment of hypertension and others which are designed and synthesized in our laboratory possessing structural characteristics necessary for antihypertensive activity. In this study, two synthetic non-peptide AT(1) antagonists, are structurally elucidated and their conformational properties and bioactivity are compared to the prototype and first approved drug of this category in the market; losartan (trade name: COZAAR).