Serial Magnetic Resonance Imaging Evaluation Research Articles

Serial magnetic resonance imaging evaluation of the early reaction of all-suture anchors in arthroscopic rotator cuff repair.

The aim of this study was to evaluate the early reaction of all-suture anchors (ASAs) in arthroscopic rotator cuff repair. This retrospective case series comprised 23 patients (8 women, 15 men; mean age = 59.9 years, age range = 36-73 years) with medium-size rotator cuff tear who underwent arthroscopic rotator cuff repair. All patients underwent postoperative serial magnetic resonance imaging (MRI) evaluation 3 and 6 months postoperatively. Demographic and operative characteristics were recorded. MRIs were evaluated for osseous cyst formation, and tunnel volume was measured. Statistical analyses were performed to detect differences in the serial MRI follow-up observation. A total of 39 ASAs were evaluated. Osseous cyst formation was found in two ASAs (5.1%) at the 6-month follow-up. Tunnel expansion was significantly observed in both 3- and 6-month postoperative MRI evaluations (P < 0.001). The mean tunnel volume significantly increased 1.95 times at the 3-month follow-up and 2.84 times at the 6-month follow-up (P < 0.001). Evidence from this study has revealed low rates of cyst formation but significant increases in tunnel volume at the early follow-up following arthroscopic rotator cuff repair with ASAs. Level IV, Therapeutic Study.

Serial magnetic resonance imaging evaluations of irradiated superior cervical sympathetic ganglia: Not every retropharyngeal enlarging mass is a sign of malignancy

IntroductionTo describe serial changes in irradiated superior cervical sympathetic ganglia (SCSGs) on MRI (magnetic resonance imaging) evaluation in patients with head and neck squamous cell carcinoma (HNSCC) and to find the features differentiating them from the metastatic retropharyngeal lymph nodes. Materials and methodsThis retrospective study evaluated 52 consecutive patients with definitive radiotherapy with/without chemotherapy for pathologically confirmed HNSCC and pre- and postradiation MRI follow-up evaluations. MR images of SCSGs were analyzed including enhancement pattern, margin, and the presence of intraganglionic hypointensity. ResultsMRI evaluations were performed in 36 men and 16 women with HNSCC with an average age of 58 years, range 23–80 years before irradiation (n=52), and at 6 (n=21) and 13–18 (n=52)months follow-up. Mean total radiation dose was 6351±483 cGy (range, 5640–7000 cGy). Intraganglionic hypointensity, homogeneous enhancement pattern, and well-defined margins were observed in 96%, 97%, and 97% of ganglia on the last follow-up, which showed no difference between pretreatment and 6-month follow-up (P>0.05). Mixed linear model analysis revealed significant increases in diameter and normalized T2SI of SCSGs after irradiation (P< 0.05). ConclusionsDespite of the increase in diameter and normalized T2SI of SCSGs, preservation of intraganglionic hypointensity, well-defined margins and homogeneous enhancement might be helpful for radiologists to identify SCSGs during the follow-up of HNSCC patients.

Low intensity lympho-ablative regimen followed by autologous hematopoietic stem cell transplantation in severe forms of multiple sclerosis: A MRI-based clinical study

Background: Autologous hematopoietic stem cell transplantation (AHSCT) has been successfully used to treat aggressive forms of multiple sclerosis (MS) that are unresponsive to approved therapies. In the last years, in view of the risk of mortality related to the procedure, the utilization of low-intensity conditioning regimens has been considered. Objective: To report magnetic resonance imaging (MRI) and clinical data in a small cohort of patients treated with a low-intensity lympho-ablative regimen, followed by AHSCT. Methods: Seven patients affected by relapsing–remitting MS (RRMS) underwent AHSCT, with cyclophosphamide 120 mg/kg in 2 days as the conditioning regimen; and were then followed with serial MRI evaluations until 36 months, with clinical evaluations until 60 months. Results: The mean number of gadolinium (Gd)-enhancing lesions significantly decreased after treatment, but a complete suppression of inflammatory activity was not obtained. No deaths occurred, but every patient developed adverse events, although not severe. After 5 years of follow-up, two patients remained stable, one patient markedly improved and four patients had a mild progression of the disease. Only one patient experienced a relapse after treatment. Conclusion: A low-intensity conditioning regimen with AHSCT has a profound effect on MRI inflammation and relapses, but is not able to completely abrogate MRI activity and disease progression of aggressive RRMS.

Transient enlargement of craniopharyngioma after radiation therapy: pattern of magnetic resonance imaging response following radiation

Clinical experience suggests that craniopharyngiomas may temporarily increase in size after radiation therapy (RT). The study goal is to determine the incidence and natural history of this response in a cohort of patients managed at Children's Healthcare of Atlanta (CHOA) or Emory Healthcare (EHC). Between 08/1998 and 06/2009, 41 children and young adults were diagnosed with craniopharyngioma at CHOA and/or EHC. Of these, 21 received external-beam radiation and were included in our analysis. Serial magnetic resonance imaging (MRI) studies were evaluated volumetrically to assess response to RT. Median age at diagnosis was 8.2 years (range 3.2-23.5 years). Median radiation dose was 54.0 Gy using standard fractionation (1.8-2.0 Gy/day). With median follow-up of 41.3 months (range 7.2-121.8 months), actuarial local control and overall survival rates at 5 years were 78.7 % and 100 %, respectively. Of subjects, 52.4 % of subjects (11 of 21) were noted on serial MRI evaluation to have tumor enlargement (mostly cystic component) after radiation before eventual shrinkage without further intervention. For tumors that expanded, the median volume increase was 33.9 % (range 15.6-224.4 %). Median time to maximal tumor/cyst expansion was 1.5 months (range 1.0-5.0 months). Finally, nearly all patients (20 of 21) showed a measurable objective response to therapy by MRI regardless of ultimate disease control. Median time to maximal response post-radiation, as defined by MRI, was 9.5 months (range 3.5-39.9 months). In summary, RT is effective for managing craniopharyngioma. However, despite good ultimate responses, approximately 50 % of the patients show tumor/cyst expansion on MRI over the first few months post-radiation. Caution should be taken not to subject these patients to "salvage surgery" or cyst aspiration during this early time unless there are other overriding surgical indications. Understanding the natural history of this phenomenon could potentially help guide the management of these craniopharyngioma patients.

Diagnosis of Iron Overload and Heart Disease by Magnetic Resonance Imaging

The use of Magnetic resonance imaging (MRI) to estimate tissue iron was initiated nearly three decades ago but has only become a practical reality in the last ten years. MRI is most often used to estimate hepatic and cardiac iron in patients with thalassemia or sickle cell disease and has largely replaced liver biopsy for liver iron quantification. The ability of MRI to image extra hepatic organs has really transformed our understanding of iron mediated toxicity in transfusional siderosis. For decades, iron cardiomyopathy was the leading cause of death in thalassemia major, but it is now relatively rare in centers with regular MRI screening. Early recognition of cardiac iron loading allows more gentle modifications of iron chelation therapy prior to life threatening organ dysfunction. Serial MRI evaluations have demonstrated differential kinetics of uptake and clearance among the difference organs of the body. Although elevated serum ferritin and liver iron concentration increase the risk of cardiac and endocrine toxicities, extra hepatic iron deposition and toxicity occurs in many patients despite having low total body iron stores; there is no safe liver iron level in chronically transfused patients. Instead, the type, dose, and pattern of iron chelation therapy all contribute to whether cardiac iron accumulation will occur. These observations, coupled with the advent of increasing options for iron chelation therapy, are allowing clinicians to more appropriately tailor chelation therapy to individual patient needs, producing greater efficacy with fewer toxicities. With the decline in cardiac mortality, future frontiers in MRI monitoring including better prevention of endocrine toxicities, particularly hypogonadotropic hypogonadism and diabetes. These organs also serve as early warning signals for inadequate control of non-transferrin bound iron, a risk factor for cardiac iron loading. Thus MRI assessment of extra hepatic iron stores is a critical monitoring tool for chronically transfused patients. Further prospective work is necessary to determine whether markers of endocrine and exocrine pancreatic function can be used as surrogates of cardiac risk in regions where MRI is not available.

Inter-stage right ventricular remodeling in hypoplastic left heart syndrome

Background Magnetic resonance imaging (MRI) can be used as a means of pre-operative evaluation of the cardiac anatomy and function in patients with hypoplastic left heart syndrome (HLHS) prior to superior and total cavo-pulmonary connection (TCPC). Serial MRI evaluation prior to each cavo-pulmonary palliation allows us to demonstrate the remodelling of the right ventricle. Methods A retrospective analysis of the serial MRI scans of all patients with HLHS who had undergone palliation through to completion of Fontan was undertaken. Re-analysis was undertaken by two members of the research team who had previously shown good intrauser variability. Ethical and institutional approval was obtained. All scans had been performed with general anaesthesia on a Philips 1.5 Tesla Intera MRI scanner. Results 51 patients had undergone completion of Fontan and had MRI scans performed prior to each cavo-pulmonary connection available for analysis. Median (range) age in years at the first MRI, superior cavopulmonary connection, pre-TCPC MRI and TCPC was 0.44 (0.12-1.02), 0.57 (0.13-1.37), 2.80 (1.80-5.52), 3.26 (2.28-6.76) respectively. Right ventricular (RV) volumes indexed to body surface area are demonstrated in table 1. There was a marked reduction in indexed RV end diastolic volume (iEDV), indexed RV end systolic volume (iESV). Indexed stroke volume (iSV) remained constant, but indexed cardiac output (iCO) fell, likely due to the decrease in heart rate (HR) between the two scans. There was an increase in global ejection fraction (EF).

Observed magnetic resonance imaging changes in pediatric patients treated with stereotactic radiosurgery for intracranial tumors

PurposeThis study seeks to characterize magnetic resonance imaging (MRI) changes following stereotactic radiosurgery (SRS) of pediatric brain malignancies.MethodsSerial MRI evaluations were performed on 21 lesions treated with SRS for either medulloblastoma (n = 12), juvenile pilocytic astrocytoma (n = 4), ependymoma (n = 2), atypical rhabdoid teratoid tumor (n = 2), or pineocytoma (n = 1). Prescription doses ranged from 14 to 30 Gy in one to five fractions. Tumor response was qualified as complete (CR), partial (PR), stable disease (SD), or progressive disease (PD) according to the RECIST v1.1. Median radiographic follow-up after SRS was 17 months.ResultsA total of 80 follow-up MRI scans were reviewed with a median of eight per patient. During serial MRI evaluation, eight lesions met criteria for PD at a median of 6 months. However, of these, three (37%) represented transient tumor edema with two lesions later developing a CR at a median of 15 months and one persisting as SD at 12 months. The remaining five lesions were true local failures. Of the 13 lesions that did not show evidence of PD, a CR was obtained in 11 lesions at a median of 3 months (range, 2–6), and SD was seen in the remaining two tumors at last follow-up.ConclusionLesion enlargement following SRS for pediatric intracranial tumors is common, and a proportion of patients meeting requirements for PD at early radiographic follow-up may later develop complete resolution of their lesions. Physicians should be aware of these radiographic changes to avoid unwarranted medical and surgical interventions.

OUTCOME OF CHIARI-ASSOCIATED SYRINGOMYELIA AFTER HINDBRAIN DECOMPRESSION IN CHILDREN

Chiari I malformation is complicated by syringomyelia in many cases. Hindbrain decompression remains first-line surgical treatment; however, the incidence, time course, and predictors of syrinx resolution remain unclear. We set out to determine predictors of syrinx improvement after hindbrain decompression for Chiari I- associated syringomyelia. Forty-nine consecutive pediatric patients undergoing posterior fossa decompression for Chiari I-associated syringomyelia were followed with serial magnetic resonance imaging evaluations postoperatively. Clinical, radiological, and operative variables were assessed as predictors of syrinx improvement as a function of time using Kaplan-Meier plots and log-rank analysis. Mean patient age was 11 +/- 5 years. Syringomyelia was symptomatic in 39 (80%) and asymptomatic in 10 (20%) cases. Twenty-one (54%) patients experienced symptom resolution (median, 4 mo postoperatively). Twenty-seven (55%) patients experienced radiographic improvement in syringomyelia (median, 14 mo postoperatively). After hindbrain decompression, motor symptoms were associated with a 2.35 increased hazard ratio for symptom improvement (P = 0.031) versus all other symptoms. Among patients with sensory deficits, dysesthesia was associated with a 3.12 increased hazard ratio for symptom improvement (P = 0.032) versus symptoms of paresthesia or anesthesia. In our experience, just more than one-half of patients with Chiari- associated syringomyelia demonstrated clinical and radiographic improvement after hindbrain decompression. Median time to radiographic improvement lagged behind clinical improvement by 10 months. Motor symptoms were more likely to improve with hindbrain decompression. Paresthesia or anesthesia symptoms were less likely to improve with hindbrain decompression. These findings may help guide surgical decision making and aid in patient education.

Serial Multimodality Assessment of Myocardial Infarction in Mice Using Magnetic Resonance Imaging and Micro–Positron Emission Tomography Provides Complementary Information on the Progression of Scar Formation

Recent technological advances have made imaging the mouse heart possible using both 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and magnetic resonance imaging (MRI),1–4 thus facilitating the investigation of mechanisms underlying the progression toward heart failure after myocardial infarction (MI). These imaging modalities provide complementary information regarding cellular metabolism and infarct location, respectively. To demonstrate this, we used FDG PET and MRI in a serial study of male C57Bl/6 mice that were subjected to a 1-hour coronary occlusion and then 30 days of reperfusion. Imaging was performed 1, 7, and 28 days after coronary occlusion. Gd-enhanced ECG-gated cardiac MRI was performed using a 4.7-T MRI scanner (Varian, Inc, …

The course of the patellar tendon after reharvesting its central third for ACL revision surgery: a long-term clinical and radiographic study

The choice of the optimal graft for anterior cruciate ligament (ACL) revision surgery is still controversial. Reharvesting the patellar tendon has been suggested as one graft alternative. Our hypothesis was that in the long-term, ACL revision surgery using reharvested patellar tendon autografts would render a good clinical outcome and a normal patellar tendon at the donor site as seen on magnetic resonance imaging (MRI). Fourteen consecutive patients (five women, nine men), who underwent ACL revision surgery using reharvested ipsilateral patellar tendon grafts, were included in the study. They underwent bilateral MRI evaluations of the patellar tendon and were tested for clinical outcome 26 (20-35) and 115 months (102-127) after the revision procedure. On the second occasion, they also underwent standard weight-bearing X-ray examinations. The serial MRI evaluations revealed that the thickness of the patellar tendon at the donor site was significantly increased compared with the non-harvested, normal contralateral side and that the donor-site gap was still visible after 10 years. No significant differences were seen between the 2- and 10-year MRI evaluations. Standard weight-bearing X-ray examinations revealed signs of mild degenerative changes in all patients. Clinical results in terms of the Lysholm score, IKDC evaluation system, one-leg-hop test, KT-1000 laxity test and the knee-walking test revealed no significant differences between the 2- and 10-year assessments. In overall terms, the clinical results were considered to be poor on both occasions. The patellar tendon at the donor site had not normalised 10 years after the reharvesting procedure, as seen on MRI. Furthermore, the clinical results were poor after ACL revision surgery using reharvested patellar tendon autograft.

Spontaneous involution of a non‐optic astrocytoma in neurofibromatosis type I: serial magnetic resonance imaging evaluation

A patient with neurofibromatosis type I (NF1) was followed-up with serial magnetic resonance imaging (MRI) studies over a period of 6 years. A contrast-enhancing lesion of the internal capsule, histologically proven to be pilocytic astrocytoma through stereotactic brain biopsy with mass effect and associated edema, was detected to reveal spontaneous involution on follow-up MRI studies. Although spontaneous regression of gliomas of the optic pathway-hypothalamus in patients with NF1 is relatively common in the literature, spontaneous involution of non-optic (i.e. areas other than optic pathways and hypothalamus) gliomas is rarely reported. Conservative management with follow-up MRI studies should be considered for non-optic glial tumors and tumor-like masses in patients with NF1, and surgical treatment should not be considered unless the lesions exhibit a rapid or unrelenting growth on serial MRI studies or produce significant clinical deterioration.

Serial magnetic resonance imaging evaluation of the patellar tendon after posterior cruciate ligament reconstruction

Purpose: Our purpose was to prospectively analyze serial changes in magnetic resonance imaging (MRI) signal of the bone–patellar tendon–bone autograft when used for posterior cruciate ligament (PCL) reconstruction and to retrospectively determine at mid-term follow-up the relationship between MRI graft appearance and clinical stability in patients who have undergone arthroscopic PCL reconstruction with a bone–patellar tendon–bone autograft. Type of Study: One prospective serial blinded study and 1 retrospective blinded study. Methods: The first part of the study focused on MRI scans obtained at 3, 6, 9, and 12 months postoperatively in a case series of 10 consecutive patients who underwent arthroscopically assisted PCL reconstruction (group A), and of 10 patients who underwent combined ACL-PCL arthroscopic reconstruction (group B). For the second part of the study, MRI scans were obtained in a retrospective series of 10 patients at mid-term follow-up after PCL arthroscopic reconstruction (group C). Signal intensity of 3 zones, corresponding to the proximal, middle, and distal intra-articular graft zones, was evaluated according to the Howell et al. classification. Fiber continuity assessment was performed using a modified Kühne et al. score. The signal intensity of the 3 zones was independently scored. Knee stability was clinically and instrumentally graded according to the IKDC evaluation form (group 4). A multivariance analysis and grouped t test were used for statistical evaluation. Results: In group A, the average MRI evaluation score was 7.65 ± 1.6 at 3 months, 3.8 ± 0.6 at 6 months, 4.75 ± 1 at 9 months and 6.25 ± 1.2 at 1 year. The portion of graft exiting the femoral tunnel exhibited increased signal and faster maturation than the tibial tunnel. In group B (combined ACL-PCL reconstruction), the graft showed slower graft healing with an average MRI score of 4.85 ± 0.7 at 3 months, 1.9 ± 0.7 at 6 months, 3.9 ± 0.9 at 9 months, and 5.3 ± 1.1 at 1 year. At 1 year follow-up, there was no correlation between MRI appearance and stability in group A, even with MRI findings of fiber continuity. However, at long-term evaluation (group C), a strict correlation between MRI appearance and achieved stability was found. Conclusions: The patellar tendon when used for PCL reconstruction requires more than 1 year to achieve a low-signal intensity over its entire course, and the distal zone near the tibial tunnel shows a slower healing process. MRI graft assessment is useful only 1 year or more following PCL reconstruction.

Serial Magnetic Resonance Imaging Evaluation of Bioabsorbable Interference Screws in Anterior Cruciate Ligament Reconstruction

Purpose : To evaluate the changes at the postoperative site of anterior cruciate ligament (ACL) reconstruction, in which bioabsorbable screws were used for fixation, by magnetic resonance imaging (MRI) and to evaluate the efficacy and safety of (Linvatec, Largo, FL). Materials and Methods : This prospective study was initiated in May 1997 upon 38 patients receiving . All patients with arthroscopically assisted primary reconstruction of ACL involving fixation with Bioscrews were examined 3, 6, 12 and 24 months after operation by Lysholm score, KT-2000 arthrometer and MRI. MR Images were interpreted by musculoskeletal radiologists. Results : There were no complications related to loss of fixation. The Lysholm scores and the KT-2000 arthrometer measurement at final follow-up were 95.6 and 1.8 mm respectively. Even after two years there was evidence of screw material in all cases. MRIs taken at 3 months showed fluid collections inside the tibial tunnel (n=3) and the anterior aspect of the tibial tunnel (n=1), Though these fluid collections disappeared gradually. Varying amounts of edma were observed around the tunnels. We divided the bone edema into the ring (n=5) and diffuse types (n=16), which disappeared gradually. Conclusion : The was found to be a safe and effective alternative for fixation in ACL reconstruction, but requires the long term follow-up to confirm its safety.

Serial Magnetic Resonance Imaging Evaluation of Operative Site After Fixation of Patellar Tendon Graft With Bioabsorbable Interference Screws in Anterior Cruciate Ligament Reconstruction

Summary: Magnetic resonance imaging (MRI) is accepted as the imaging procedure of choice for showing internal derangement of the knee. In contrast to metal implants, bioabsorbable interference screws do not produce an artifact and provide an opportunity to expand the evaluation of the postoperative anterior cruciate ligament (ACL) ligament repair. There is the potential to evaluate the implant, the graft, the adjacent tissue, and the surgically created bone tunnels. The purpose of this study was to evaluate with MRI the postoperative site of ACL patellar tendon autografts in which bioabsorbable screws were used for fixation. It was hypothesized that a time line of bone tissue changes resulting from this type of surgery could be developed based on the expanded evaluation of MRI. From January 1993 through October 1997, 270 patients underwent surgical repair of a disrupted native ACL. There were 173 men 97 women; the average age was 25.1 years. (range, 17 to 50 years). There were 155 right knees and 115 left knees. In addition to the conventional postoperative clinical assessment and plain film radiographs, opportunistic MRIs were obtained with the patient's permission. The examinations were performed at different postoperative intervals from the third postoperative day to 4 years postoperatively. A total 206 MRIs from various time intervals were available for study. The study protocol was designed to look for loss of integrity of the screws, adjacent fluid collection, tunnel widening, and tunnel healing or narrowing. The hypothesis was substantiated in this study. The use of MRI provided observations not available by other imaging methods. The absence of metal implants for fixation provided an opportunity to examine the adjacent tissue in detail and to form a time line of the tissue response in this type of surgery. Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 15, No 7 (October), 1999: pp 709–718

Serial Magnetic Resonance Imaging Evaluation of a Bioabsorbable Interference Screw and the Adjacent Bone

Summary: The purpose of this prospective study was to review, using expanded clinical assessment tools, the initial use of a bioabsorbable interference screw (copolymer 85/15 D, L lactide/glycolide) in anterior cruciate ligament (ACL) reconstruction at the Wels Hospital, Austria. The study enlisted 32 patients of whom 28 were available for follow-up at minimum of 2.5 years. Since the implant material was new and the screw would not show on plain film radiographs, the clinical assessment was expanded beyond the usual historical and physical findings. The evaluation included opportunistic knee joint aspiration and repeat magnetic resonance imaging (MRI) studies to investigate the longevity of the implant and potential adverse effects of this new bioabsorbable material. The knee joint aspirations showed no infection. Serial MRIs showed the physical presence of the screw to remain intact for 4 months and disappear in 6 months. The MRIs showed minimal collection of edema around the bone tunnels that resolved by 12 months. There were no symptoms or adverse clinical result correlated with the MRI evidence of edema. There was temporary bone tunnel expansion. The clinical results were good. The OAK-score (Orthopädische Arbeitsgruppe Knie) showed 89.5 % excellent and good results, 7% fair results and 3.5 % poor results. The average score was 90.7 points (range, 63 to 100 points). The knee joint stability measured with the KT-1000 arthrometer showed 93% to have a 3-mm or less difference compared with the unoperated knee. This bioabsorbable interference screw appeared safe and effective for fixation of bone blocks during ACL reconstruction while producing no occult infection or adverse clinical response during the degradation process.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 15, No 5 (July-August), 1999: pp 481–488

Serial magnetic resonance imaging of the donor site after harvesting the central third of the patellar tendon. A prospective study of 37 patients after arthroscopic anterior cruciate ligament reconstruction.

The aim of this prospective study was to follow the development of repair tissue in the donor-site area using serial magnetic resonance imaging (MRI) evaluation and to assess whether the MRI findings were correlated with donor-site morbidity. Thirty-seven consecutive patients with unilateral anterior cruciate ligament injuries undergoing elective reconstruction of the ligament were included in the study. They were aged 27 (range 14-50) years. The graft was harvested through two 25-mm vertical incisions with the aim of protecting the infrapatellar nerve and sparing the paratenon. The tendon defect was left open. The patients underwent MRI evaluation at 6 weeks, 6 months and 27 months postoperatively. A final clinical follow-up was made 25 (range 23-29) months postoperatively. MRI demonstrated that the donor-site gap, i.e. the area corresponding to a pathological non-tendinous-like tissue signal, was 9 (range 4-18) mm at 6 weeks, 5 (range 2-14) mm at 6 months and 2 (range 0-5) mm at 27 months. The size of the donor-site gap had significantly decreased at 6 months compared with 6 weeks (P = 0.0001), as well as at 27 months compared with 6 months (P = 0.0001). We conclude that the patellar tendon at the donor site healed gradually, as expressed by a decrease in the area of non-tendinous-like tissue signal on the serial MRI evaluations.