Post-treatment Magnetic Resonance Imaging Research Articles

Incidence of silent cerebral lesions using different ablation technologies

Cerebral lesions (SCL) have been detected on post interventional magnetic resonance imaging (MRI) in asymptomatic patients after atrial fibrillation (AF) ablation procedures. Studies comparing different technologies have identified energy delivery technique as a potential confounder of SCLs. The present study evaluates incidence and potential contributing factors for SCL in a large cohort of patients undergoing radiofrequency (RF), endoscopic laser balloon (EAS) or cryo-balloon (CB) ablation of AF. Methods: All patients eligible for pre- and post-ablation MRI were included. Patients underwent AF ablation using cooled-tip single-tip RF (group 1), multipolar phased RF (group 2), EAS (group 3) or CB (group 4) ablation. MRI was performed before, after and in cases of detected SCL 2 to 6 weeks after ablation. All ablations were carried out according to a standardized protocol under heparinization with ACTs > 300seconds. SCL were defined as new onset lesion with hyperintense signal in diffusion weighted imaging and hypointense signal on apparent diffusion coefficient map. The fluid attenuated inversion recovery sequence was not considered in regard to SCL definition. Results: A total of 237 patients were included and no patient had acute cerebral lesions identified on pre-ablation MRI. On post-ablation MRI 83 patients (35%) had a total of 232 SCLs (2.8/pt). 20% of group 1, 41% of group 2, 37% of group 3 and 21% of group 4 patients had documented SCLs. When dividing group 2 into patients only undergoing pulmonary vein isolation (PVI) using the PVAC 37% (48 out of 118) had SCL and 78% (11 out of 14) undergoing PVI plus additional phased RF ablations had SCLs. Within group 1: 2.3 SCL/pt, group 2: 2.6/pt in PVI alone and 4.7/pt in PVI plus, in group 3: 2.3lesions/pt and in group 4 2.3/pt were identified. During follow-up of 2 to 6 weeks only 5 lesions (2% of SCLs) (all > 10mm diameter) were still identified on MRI and all other lesions were not detected any more. Left atrial dilation and use of additional phased RF ablation were the only significant predictors of SCL occurrence. Conclusions: SCL may be identified in a substantial portion of patients undergoing AF ablation. Incidence of SCL may vary according to the technology used. The incidence and number of lesions appears to be highest using phased RF PVI plus additional left atrial phased RF ablations. 98% of lesions appear to resolve in follow-up MRI and only large lesions (> 10mm) may cause cerebral scarring. Variable MRI-definitions and -technology may cause differences in incidences of SCLs.

Recurrent glioblastoma: Volumetric assessment and stratification of patient survival with early posttreatment magnetic resonance imaging in patients treated with bevacizumab

Despite a high radiographic response rate in patients with recurrent glioblastoma following bevacizumab therapy, survival benefit has been relatively modest. We assess whether tumor volume measurements based on baseline and early posttreatment MRI can stratify patients in terms of progression-free survival (PFS) and overall survival (OS). Baseline (-4 +/- 4 days) and posttreatment (30 +/- 6 days) MRI exams of 91 patients with recurrent glioblastoma treated with bevacizumab were retrospectively evaluated for volume of enhancing tumor as well as volume of the T2/FLAIR hyperintensity. Overall survival (OS) and progression-free survival (PFS) were assessed using volume parameters in a Cox regression model adjusted for significant clinical parameters. In univariable analysis, residual tumor volume, percentage change in tumor volume, steroid change from baseline to posttreatment scan, and number of recurrences were associated with both OS and PFS. With dichotomization by sample median of 52% change of enhancing volume can stratify OS (52 weeks vs. 31 weeks, P = .013) and PFS (21 weeks vs. 12 weeks, P = .009). Residual enhancing volume, dichotomized by sample median of 7.8 cm(3) , can also stratify for OS (64 weeks vs. 28 weeks, P < .001) and PFS (21 weeks vs. 12 weeks, P = .036). Volumetric percentage change and absolute early posttreatment volume of enhancing tumor can stratify survival for patients with recurrent glioblastoma receiving bevacizumab therapy.

Applicators for Magnetic Resonance–Guided Ultrasonic Ablation of Benign Prostatic Hyperplasia

The aims of this study were to evaluate in a canine model applicators designed for ablation of human benign prostatic hyperplasia (BPH) in vivo under magnetic resonance imaging (MRI) guidance, including magnetic resonance thermal imaging (MRTI), determine the ability of MRI techniques to visualize ablative changes in prostate, and evaluate the acute and longer term histologic appearances of prostate tissue ablated during these studies. An MRI-compatible transurethral device incorporating a tubular transducer array with dual 120° sectors was used to ablate canine prostate tissue in vivo, in zones similar to regions of human BPH (enlarged transition zones). Magnetic resonance thermal imaging was used for monitoring of ablation in a 3-T environment, and postablation MRIs were performed to determine the visibility of ablated regions. Three canine prostates were ablated in acute studies, and 2 animals were rescanned before killing at 31 days postablation. Acute and chronic appearances of ablated prostate tissue were evaluated histologically and were correlated with the MRTI and postablation MRI scans. It was possible to ablate regions similar in size to enlarged transition zone in human BPH in 6 to 18 minutes. Regions of acute ablation showed a central "heat-fixed" region surrounded by a region of more obvious necrosis with complete disruption of tissue architecture. After 31 days, ablated regions demonstrated complete apparent resorption of ablated tissue with formation of cystic regions containing fluid. The inherent cooling of the urethra using the technique resulted in complete urethral preservation in all cases. Prostatic ablation of zones of size and shape corresponding to human BPH is possible using appropriate transurethral applicators using MRTI, and ablated tissue may be depicted clearly in contrast-enhanced magnetic resonance images. The ability accurately to monitor prostate tissue heating, the apparent resorption of ablated regions over 1 month, and the inherent urethral preservation suggest that the magnetic resonance-guided techniques described are highly promising for the in vivo ablation of symptomatic human BPH.

A Novel Biological Approach to Treat Chondromalacia Patellae

Mesenchymal stem cells from several sources (bone marrow, synovial tissue, cord blood, and adipose tissue) can differentiate into variable parts (bones, cartilage, muscle, and adipose tissue), representing a promising new therapy in regenerative medicine. In animal models, mesenchymal stem cells have been used successfully to regenerate cartilage and bones. However, there have been no follow-up studies on humans treated with adipose-tissue-derived stem cells (ADSCs) for the chondromalacia patellae. To obtain ADSCs, lipoaspirates were obtained from lower abdominal subcutaneous adipose tissue. The stromal vascular fraction was separated from the lipoaspirates by centrifugation after treatment with collagenase. The stem-cell-containing stromal vascular fraction was mixed with calcium chloride-activated platelet rich plasma and hyaluronic acid, and this ADSCs mixture was then injected under ultrasonic guidance into the retro-patellar joints of all three patients. Patients were subjected to pre- and post-treatment magnetic resonance imaging (MRI) scans. Pre- and post-treatment subjective pain scores and physical therapy assessments measured clinical changes. One month after the injection of autologous ADSCs, each patient's pain improved 50–70%. Three months after the treatment, the patients' pain improved 80–90%. The pain improvement persisted over 1 year, confirmed by telephone follow ups. Also, all three patients did not report any serious side effects. The repeated magnetic resonance imaging scans at three months showed improvement of the damaged tissues (softened cartilages) on the patellae-femoral joints. In patients with chondromalacia patellae who have continuous anterior knee pain, percutaneous injection of autologous ADSCs may play an important role in the restoration of the damaged tissues (softened cartilages). Thus, ADSCs treatment presents a glimpse of a new promising, effective, safe, and non-surgical method of treatment for chondromalacia patellae.

Recurrent glioblastoma: Stratification of patient survival using tumor volume before and after antiangiogenic treatment.

2075 Background: Although antiangiogenic therapies can induce a dramatic clinical and imaging response in patients with recurrent glioblastoma, their benefit on overall survival is less pronounced. We assessed whether tumor volume based on magnetic resonance imaging (MRI) before and after treatment with bevacizumab can stratify patients in terms of progression-free survival (PFS) and overall survival (OS). Methods: Baseline and post-treatment MRI scans of 93 patients with recurrent glioblastoma treated with bevacizumab were evaluated for volume of the enhancing tumor, as well as volume of the T2/FLAIR hyperintensity. The Cox proportional hazards model was used in univariate and multivariate settings to identify volume parameters prognostic and predictive for PFS and OS. Results: Our results show that baseline enhancing tumor volume were predictive of PFS (p = 0.047) and OS (p = 0.011). Specifically, patients with pretreatment enhancing tumor volume less than 18 cm3 have a median OS of 45 weeks, while patients with tumor volume greater than 18 cm3 have a median OS of 26 weeks. In addition, enhancing tumor volume 3 to 6 weeks after treatment, as well as percentage change in volume, are independent predictors of PFS and OS. Neither T2/FLAIR volume nor percentage change in T2/FLAIR volume was associated with survival. Conclusions: These results indicate that measurement of enhancing tumor volume can help identify patients more likely to benefit from bevacizumab therapy.

2:02 PM Abstract No. 85 - Image-guided targeted radiofrequency ablation (t-RFA) of spinal tumors using a novel bipolar navigational device: multicenter initial clinical experience

Purpose Report initial clinical experience and determine the efficacy and safety of targeted radiofrequency ablation (t-RFA) of malignant spinal lesions using a novel bipolar RF ablation system. Demonstrate the use of temperature monitoring of thermocouples (TC) on an articulating electrode to determine ablation size and morphology with use of post-ablation magnetic resonance imaging (MRI) and comparison with pre-clinical thermal distribution curves. Materials and Methods 101 spinal lesions in 73 procedures were treated at six centers. The STAR Tumor Ablation System includes a robust articulating, navigational bipolar electrode containing two active TCs positioned to permit real time monitoring of the peripheral edge of the ablation zone to determine size of ablation. Treatment was controlled by adjusting power while monitoring TC temperature in-situ. Access and number of ablations were based on lesion size, location and ability to articulate the bipolar electrode. Cement augmentation via the same guiding cannula was performed when required. In some cases, post-procedural MRI was performed. Pain was assessed pre- and postprocedurally. Results Lesion etiology included a wide variety of metastatic lesions from T2 to S2 and ilium. No complications or thermal injury occurred. Cement augmentation following t-RFA was efficient and resulted in predictable cement filling. Postablation MRIs demonstrated discrete ablation zones with 3:2 length-to-width aspect ratio consistent in size with thermal monitoring by TCs during the ablation. All patients reported pain relief. Conclusion The STAR device was safely and effectively used in the navigation and t-RFA of spinal malignant lesions. Postablation MRIs confirmed lesions were included in the ablation zone with necrosis of the lesion. The ablation zone was consistent in size with that measured by the TCs and similar in morphology to that extrapolated from thermal distribution curves. The STAR navigational ability allowed for easy access to posterior vertebral body lesions, previously difficult to access with other ablation devices. In many cases, this technique allowed for treatment of individual lesions not controlled by systemic or radiation therapy.

MR Imaging–guided Focal Laser Ablation for Prostate Cancer: Phase I Trial

To evaluate the feasibility and safety of magnetic resonance (MR) imaging-guided laser-based thermotherapy in men with clinically low-risk prostate cancer and a concordant lesion at biopsy and MR imaging. This HIPAA-compliant phase I prospective study was approved by the institutional review board. Informed consent was obtained from all patients. Transperineal MR imaging-guided focal laser ablation for clinically low-risk prostate cancer was performed in patients with a Gleason score of 7 or less in three or fewer cores limited to one sextant obtained with transrectal ultrasonography (US)-guided biopsy and a concordant lesion at MR imaging. Lesions were targeted with a laser ablation system. Periprocedural complications were recorded. The International Prostate Symptom Score (IPSS) and the Sexual Health Inventory for Men (SHIM) score were collected before and after the procedure. MR imaging-guided biopsy of the ablation zone was performed 6 months after treatment. The prostate-specific antigen level, IPSS, and SHIM score before and after ablation were compared by using the Wilcoxon signed rank test. Treatment was successfully completed in nine patients (procedure duration, 2.5-4 hours; mean laser ablation duration, 4.3 minutes). Immediate contrast-enhanced posttreatment MR imaging showed a hypovascular defect in eight patients. Self-resolving perineal abrasion and focal paresthesia of the glans penis each occurred in one patient. The mean (± standard deviation) IPSS and SHIM score at baseline were 5.8 ± 5.3 and 19.0 ± 8.0, respectively. Average score changes were not significantly different from zero during follow-up (P = .18-.99). MR imaging-guided biopsy of the ablation zone showed no cancer in seven patients (78%) and Gleason grade 6 cancer in two (22%). Transperineal MR imaging-guided focal laser ablation appears to be a feasible and safe focal therapy option for clinically low-risk prostate cancer.

MR-guided focused ultrasound technique in functional neurosurgery: targeting accuracy.

BackgroundThe purpose of this study was to describe targeting accuracy in functional neurosurgery using incisionless transcranial magnetic resonance (MR)-guided focused ultrasound technology.MethodsMR examinations were performed before and 2 days after the ultrasound functional neurosurgical treatment to visualize the targets on T2-weighted images and determine their coordinates. Thirty consecutive targets were reconstructed: 18 were in the central lateral nucleus of the medial thalamus (central lateral thalamotomies against neurogenic pain), 1 in the centrum medianum thalamic nucleus (centrum medianum thalamotomy against essential tremor), 10 on the pallido-thalamic tract (pallido-thalamic tractotomies against Parkinson's disease), and 1 on the cerebello-thalamic tract (cerebello-thalamic tractotomy against essential tremor). We describe a method for reconstruction of the lesion coordinates on post-treatment MR images, which were compared with the desired atlas target coordinates. We also calculated the accuracy of the intra-operative target placement, thus allowing to determine the global, planning, and device accuracies. We also estimated the target lesion volume.ResultsWe found mean absolute global targeting accuracies of 0.44 mm for the medio-lateral dimension (standard deviation 0.35 mm), 0.38 mm for the antero-posterior dimension (standard deviation 0.33 mm), and 0.66 mm for the dorso-ventral dimension (standard deviation 0.37 mm). Out of the 90 measured coordinates, 83 (92.2%) were inside the millimeter domain. The mean three-dimensional (3D) global accuracy was 0.99 mm (standard deviation 0.39 mm). The mean target volumes, reconstructed from surface measurements on 3D T1 series, were 68.5 mm3 (standard deviation 39.7 mm3), and 68.9 mm3 (standard deviation 40 mm3) using an ellipsoidal approximation.ConclusionThis study demonstrates a high accuracy of the MR-guided focused ultrasound technique. This high accuracy is due not only to the device qualities but also to the possibility for the operator to perform on-going real-time monitoring of the lesioning process. A precise method for determination of targeting accuracy is an essential component and basic requirement of the functional neurosurgical activity, allowing an on-going control of the performed therapeutic work indispensable for any target efficiency analysis and the maintenance of a low risk profile.

Incarcerated spinal cord: A preventable surgical debacle

Incarcerated spinal cord: A preventable surgical debacle

Rituximab combination therapy in relapsing multiple sclerosis

In multiple sclerosis (MS), the presence of B cells, plasma cells and excess immunoglobulins in central nervous system lesions and in the cerebrospinal fluid implicate the humoral immune system in disease pathogenesis. However, until the advent of specific B-cell-depleting therapies, the critical role of B cells and their products in MS was unproven. Rituximab, a monoclonal antibody that depletes B cells by targeting the CD20 molecule, has been shown to effectively reduce disease activity in patients with relapsing MS as a single agent. Our investigator-initiated phase II study is the only published clinical trial in which rituximab was used as an add-on therapy in patients with relapsing MS who had an inadequate response to standard injectable disease-modifying therapies (DMTs). The primary endpoint, magnetic resonance imaging (MRI) gadolinium-enhanced (GdE) lesion number before versus after rituximab, showed significant benefit of rituximab (74% of post-treatment MRI scans being free of GdE lesions compared with 26% free of GdE lesions at baseline; p < 0.0001). No differences were noted comparing patients on different DMTs. Several secondary clinical endpoints, safety and laboratory measurements (including B- and T-cell numbers in the blood and cerebrospinal fluid (CSF), serum and CSF chemokine levels, antibodies to myelin proteins) were assessed. Surprisingly, the decline in B-cell number was accompanied by a significant reduction in the number of T cells in both the peripheral blood and CSF. Rituximab therapy was associated with a significant decline of two lymphoid chemokines, CXCL13 and CCL19. No significant changes were observed in serum antibody levels against myelin proteins [myelin basic protein (MBP) and myelin/oligodendrocyte glycoprotein (MOG)] after treatment. These results suggest that B cells play a role in MS independent from antibody production and possibly related to their role in antigen presentation to T cells or to their chemokine/cytokine production.

(18)F-FDG PET-CT for Detection of Recurrent Spinal Ependymoma.

Ependymomas are uncommon central nervous system tumors, with the spinal cord being the most common site in adults. Magnetic resonance imaging (MRI) is currently the standard imaging modality for initial diagnosis and to assess the adequacy of surgical resection and/or the response to radiation therapy. However, as in case of brain tumors, post treatment MRI might not be able to differentiate between radiation necrosis and recurrent tumors. Here we present 18F-fluorodeoxyglucose (FDG) positron emission tomography computed tomography (PET-CT) images of a 40-year-old female with recurrent spinal ependymoma. FDG PET-CT showed recurrent tumor, while MRI was equivocal in this patient (Fig. 1). Fig. 1 Ependymomas comprise about 4 % of primary central nervous tumors in adults, with spinal cord being the most common site [1]. They are the most common intramedullary spinal cord tumors in adults [2]. The age group affected most often is 30–50 years ...

Novel MRI Changes After Gamma Knife for Hypothalamic Hamartoma in a Child

Hypothalamic hamartomas (HH) are rare lesions of ectopic neural tissue arising from the wall of the hypothalamus. Patients with HH can present with gelastic seizures, precocious puberty or both 1 . Seizures are usually progressive and accompanied by worsening behavioral problems and developmental delay 1 . Stereotactic radiosurgery (SRS) has been shown to be safe and effective, resulting in improvement in s eizures and halting tumor progression. Gamma Knife (GK) radiosurgery in the treatment of hypothalamic hamartoma has reported Engel Class 1 seizure status of up to 60%, with improvement in behavioral status in some cases 2 . Post-treatment magnetic resonance (MR) imaging as reported in the literature has not demonstrated significant changes within the treated areas of a HH. The authors report the case of a four year-old boy with a symptomatic hypothalamic hamartoma treated with GK radiosurgery. Serial MR imaging after treatment revealed significant and progressive edema and swelling at the treatment site, with increased T2 signal change and gadolinium uptake lasting one year after treatment and eventually resolving spontaneously. Although not accompanied by clinical worsening, these changes have not been p reviously reported in SRS for HH.

Quantitative MRI analysis of the surface area, signal intensity and MRI index of the central bright area for the evaluation of early adjacent disc degeneration after lumbar fusion

The aim of this study was to evaluate early ASD at short-term follow-up in fused and unoperated patients with degenerative disc disease, using quantitative magnetic resonance imaging (MRI) analysis of the area, signal intensity and their product, i.e., MRI index of the central bright area of the disc as well as measures of intervertebral disc height and Pfirrmann grading scale. The further purpose was to determine whether fusion accelerates ASD compared with non-surgical treatment in short-term follow-up. One hundred and eight chronic low back patients diagnosed as L4/L5 degeneration undertook either one-level instrumented posterior lumbar interbody fusion or conservative treatment. They were followed up for about 1 year. Finally 46 fused and 45 conservatively treated patients with MRI follow-up were included. Pre- and post-treatment MRIs were compared to determine the progression of disc degeneration at the two cranial adjacent segments. The area, signal intensity and MRI index of the central bright area of the adjacent discs decreased in the operated and unoperated groups from pre-treatment to follow-up, except for an insignificant decrease of signal intensity at the second adjacent segment in the unoperated group. The changes in these parameters were statistically greater at the first than the second adjacent segment in the fused group, but not in the unoperated group. And the changes in the fused group were more pronounced than those at both neighbouring levels in the unoperated group. However, the Pfirrmann grading scale and intervertebral disc height did not detect any changes at adjacent discs in either group. Decrease in the parameters of quantitative MRI analysis indicated early degeneration at discs adjacent to lumbar spinal fusion. Fusion had an independent effect on the natural history of ASD during short-term follow-up. Continued longitudinal follow-up is required to determine whether these MRI changes lead to pathologic changes.

Palliative reirradiation for progressive diffuse intrinsic pontine glioma.

Diffuse intrinsic pontine gliomas (DIPGs) are highly aggressive tumors and have a poor prognosis. Nearly all patients experience disease progression after definitive treatment, accompanied by severe neurologic deficits and morbidity. Here, we report a series of patients treated with reirradiation for palliation of symptoms. Six patients received reirradiation for progressive DIPG at MD Anderson Cancer Center from 2007 to 2009. Progression after initial chemoradiation and salvage chemotherapy had been confirmed clinically and by magnetic resonance imaging. Each case was discussed at a multidisciplinary conference before reirradiation. Interval between the initial radiation therapy and reirradiation was 8 to 28 months. The initial radiation therapy dose was 54 to 55.8 Gy. Time to initial progression was 4 to 18 months. All of the patients had further progression on salvage chemotherapy. Reirradiation was given with concurrent chemotherapy to a dose of 20 Gy (n=4) or 18 Gy (n=1); 1 patient withdrew care after a single 2-Gy fraction. Four patients had substantial clinical improvement in symptoms, with improvement in speech (n=3), ataxia (n=3), and swallowing (n=2). Three patients showed renewed ability to ambulate after reirradiation. Four patients had decreased tumor size on posttreatment magnetic resonance imaging. The median clinical progression-free survival time was 5 months. Acute radiation-related toxicities were fatigue (n=2), alopecia (n=2), and decreased appetite (n=1). No grade 3 or 4 toxicities were reported. Reirradiation with chemotherapy may be feasible to improve symptoms and delay progression with minimal toxicity. Patients who are most likely to benefit may be those with prolonged response to initial therapy and a long interval since initial radiation.

Role of Early Postradiation Magnetic Resonance Imaging Scans in Children With Diffuse Intrinsic Pontine Glioma

To determine optimal timing of assessing postradiation radiographic response on magnetic resonance imaging (MRI) scans in pediatric patients with diffuse intrinsic pontine glioma (DIPG). Patients were treated on a prospective study at the National Cancer Institute (Protocol #06-C-0219) evaluating the effects of radiotherapy (RT). Standard RT was administered in standard fractionation over 6 weeks. Postradiation MRI scans were performed at 2 and 6-8 weeks. Eleven patients with DIPG were evaluated. Median age was 6 years (range, 4-13 years). Patients were treated with external-beam RT to 55.8 Gy (n = 10) or 54 Gy (n = 1), with a gross tumor volume to planning target volume expansion of 1.8-2.0 cm. All patients received prescribed dose and underwent posttreatment MRI scans at 2 and 6-8 weeks. Pretreatment imaging revealed compression of fourth ventricle (n = 11); basilar artery encasement (n = 9); tumor extension outside the pons (n = 11); and tumor hemorrhage (n = 2). At the 2-week scan, basilar artery encasement improved in 7 of 9 patients, and extent of tumor was reduced in 5 of 11 patients. Fourth ventricle compression improved in 6 of 11 patients but worsened in 3 of 11 patients. Presumed necrosis was observed in 5 of 11 patients at 2 weeks and in 1 additional patient at 6-8 weeks. There was no significant difference in mean anteroposterior and transverse diameters of tumor between the 2- and 6-8-week time points. Six of 11 patients had increasing ventricular size, with no evidence of obstruction. There is no significant difference in tumor size of DIPG patients who have received standard RT when measured at 2 weeks vs. 6-8 weeks after RT. The majority of patients had the largest change in tumor size at the 2-week post-RT scan, with evolving changes documented on the 6-8-week scan. Six of 11 patients had progressive ventriculomegaly without obstruction, suggestive of communicating hydrocephalus. To the best of our knowledge, this is the first documentation of this phenomenon in this cohort of patients.

Autologous Adipose Tissue-Derived Stem Cells Induce Persistent Bone-Like Tissue in Osteonecrotic Femoral Heads

Background: Osteonecrosis, also known as avascular necrosis, of the femoral head is a debilitating disorder that commonly affects 30- to 50-year-old individuals. Currently, definitive treatment is limited to total hip replacement. However, recent studies have demonstrated bone regeneration in the femoral head after the infusion of bone marrow-derived mesenchymal stem cells. In addition, local injection of adipose tissue-derived stem cells has been shown to regenerate medullary bonelike tissue 3 months after treatment. However, there have been no long-term follow-up studies on humans treated with adipose tissue-derived stem cells for osteonecrosis. Objectives: To determine if treatment with adipose tissue-derived stem cells and platelet-rich plasma leads to the regeneration of medullary bone-like tissue and long-term reduction of hip pain in patients with femoral head osteonecrosis. Methods: This report of two clinical cases was in compliance with the Declaration of Helsinki. Also, the Korean Food and Drug Administration has allowed the use of adipose tissue-derived stem cells (ADSCs) in medical treatments since 2009. To obtain ADSCs, lipoaspirates were obtained from lower abdominal subcutaneous adipose tissue. The stromal vascular fraction was separated from the lipoaspirates by centrifugation after treatment with collagenase. The stem-cell-containing stromal vascular fraction was mixed with calcium chloride-activated platelet rich plasma and hyaluronic acid, and this mixture was then injected into the diseased hip. The affected hip was reinjected with calcium chloride-activated platelet rich plasma weekly for 4 weeks. Patients were subjected to preand post-treatment magnetic resonance imaging (MRI) scans. Results: Two patients (34- and 39-year-old men) with femoral head osteonecrosis and severe hip pain were treated with adipose-derived stem cells. The MRI scans of the affected hip in both patients showed segmental areas of low signal intensity (T1 axial views) in the subchondral bones with a “double line sign” consistent with osteonecrosis. The visual analog scale score, physical therapy testing, and Harris Hip score of both patients improved after stem cell treatment. Both patients also demonstrated post-procedure improvement in their MRI scans, evidenced by positive T1 signal changes consistent with medullary bone regeneration. Further, the long-term reduction in hip pain was correlated with the MRI findings indicative of bone regeneration. Limitations: A biopsy of the regenerated tissue was not conducted in either patient. Thus, the true nature of the treatment-induced changes is unknown. Further, the MRI results may contain artifacts due to the difficulty in capturing the exact treatment location. It can only be speculated that there was neovascularization to support the newly regenerated medullary bone-like tissue. Conclusion: These 2 cases demonstrate the presence of sustained, regenerated medullary bonelike tissue in 2 severely necrotic femoral heads and suggest that this rather simple, minimally invasive percutaneous procedure may hold great promise as a therapy for patients with femoral head osteonecrosis. Key words: Femoral head osteonecrosis, avascular necrosis, bone necrosis, cell-based treatment, bone regeneration, hip pain, adipose tissue-derived stem cells, ADSC.

MRI features of the complete histopathological response of locally advanced rectal cancer to neoadjuvant chemoradiotherapy

To describe the post-chemoradiotherapy magnetic resonance imaging (MRI) features of locally advanced rectal carcinoma (LARC) in which there has been a complete histopathological response to neoadjuvant chemoradiotherapy (CRT). This retrospective cohort study was performed between January 2005 and November 2009 at a regional cancer centre. Consecutive patients with LARC and a histopathological complete response to long-course CRT were identified. Pre- and post-treatment MRI images were reviewed using a proforma for predefined features and response criteria. ymrT0 was defined as the absence of residual abnormality on MRI. Twenty patients were included in the study. Seven (35%) ypT0 tumours were ymrT0. All 13 ypT0 tumours not achieving ymrT0 appearances had a good radiological response, with at least 65% tumour reduction. The appearances were heterogeneous: in 11/13 patients the tumour was replaced by a region of at least 50% low signal on MRI, with 8/13 having ≥80% low signal, and 3/13 with 100% low signal. MRI may be useful in identifying a complete histopathological response. However, the MRI appearances of ypT0 tumours are heterogeneous and conventional MRI complete response criteria will not detect the majority of patients with a complete histopathological response.

Imaging modalities in head-and-neck cancer patients

Accurate staging and timely assessment is critical in head-and-neck cancer patients for formulating the appropriate treatment strategy. Therefore, optimizing pretreatment imaging for diagnosis is of great importance. Computerized tomography (CT), introduced in the early 70s, followed by magnetic resonance imaging (MRI) and positron emission tomography (PET), refinements in ultrasonography (USG), advances in nuclear medicine, and applications such as sentinel node lymphoscintigraphy have greatly added to diagnostic accuracy. Post-treatment CT or MRI is of value when a recurrent tumor is suspected. It can confirm the presence of such a lesion and determine its extent. This is important information for determining the possibility of salvage therapy.

Shoulder MR Arthrography: Intraarticular Anesthetic Reduces Periprocedural Pain and Major Motion Artifacts but Does Not Decrease Imaging Time

To prospectively determine whether the addition of an intraarticular anesthetic to the magnetic resonance (MR) arthrography solution has an effect on periprocedural pain, motion artifacts, and imaging time. This study was approved by the institutional review board, and written informed consent was obtained from all patients. From September 2009 to March 2010, 127 patients, most imaged for shoulder pain, were randomized into two groups. The first group (group A, 63 patients) received intraarticular injection of gadopentetate dimeglumine, ropivacaine 0.5%, and normal saline in a ratio of 1:100:100. The second group (group B, 64 patients) received intraarticular injection of gadopentetate dimeglumine and normal saline in a ratio of 1:200. Pain was assessed before and after injection and immediately after 1.5-T MR imaging and rated on a scale of 0 to 10. Motion artifact was assessed by two musculoskeletal radiologists and two fellows by using a scale of 0 to 3 (0=no artifact, 1=artifact present but not affecting diagnostic image quality, 2=artifact present and diminishing diagnostic image quality, and 3=artifact present and rendering image nondiagnostic). MR imaging time and examinations with repeated sequences were recorded. Wilcoxon rank sum, analysis of covariance, and permutation data analyses were performed. The mean pain levels before injection, after injection, and after MR imaging were 3.5, 2.3, and 2.5, respectively, for group A and 3.6, 3.1, and 3.2 for group B. After adjusting for age, sex, and preinjection pain level, the mean differences in pre- and postinjection pain and preinjection pain and post-MR imaging pain between the two groups were -0.9 (P=.017) and -0.8 (P=.056), respectively. No significant difference in mean total MR imaging time or number of patients with repeat sequences was noted. Radiologists 1 and 2 recorded grade 2 or 3 motion in six and five patients, respectively, in group A and 15 and 14 patients, respectively, in group B (P=.047 and .048, respectively). Radiologists 3 and 4 recorded grade 2 or 3 motion in 13 and 23 patients, respectively, in group A and 23 and 33 patients, respectively, in group B (P=.093 and .110, respectively). The use of an intraarticular anesthetic significantly reduces periprocedural pain and major motion artifacts associated with MR shoulder arthrography; however, total MR imaging time is not reduced.

Can we predict pathologic complete response before surgery for locally advanced rectal cancer treated with preoperative chemoradiation therapy?

Pathologic complete response has been proven to have oncological benefits for locally advanced rectal cancer treated with chemoradiation therapy. The aims of this study are to analyze and determine the factors to predict pathologic complete response for patients treated with preoperative neoadjuvant therapy. Patients with biopsy-proven, locally advanced rectal cancer were treated neoadjuvantly followed by radical surgical resection. Tumors were re-assessed after completing chemoradiation, including pelvic magnetic resonance images, colonoscopic examination, and re-biopsy. The results of examination were compared with the final pathologic status. A retrospective chart review of 166 patients was conducted. Twenty-five patients (15.1%) had pathologic complete response after chemoradiation. The 5-year overall survival rates were better in the complete response group than the residual tumor group (91.1% vs. 70.8%; P = 0.047), and there were also significant differences in the 5-year disease-free survival rates between these two groups (91.1% vs. 70.2%; P = 0.027). The prediction rates for pathologic complete response by re-biopsy, magnetic resonance images, and colonoscopy were 21.4%, 33.3%, and 53.8%, respectively. In addition, when we further combine the results of colonoscopic findings and re-biopsy, the prediction rate for pathologic complete response reached 77.8% (P = 0.009). Combining the results of the re-biopsy and post-treatment colonoscopic findings, we can achieve a good prediction rate for pathologic complete response. Post-treatment magnetic resonance images are not useful tools in predicting tumor clearance following chemoradiation.