Equivocal Magnetic Resonance Imaging Research Articles

Clinical decision-making based on 11C-methionine PET in recurrent Cushing's disease with equivocal MRI findings.

Diagnosis and accurate localization of recurrent tumors in Cushing's disease (CD) are challenging, especially after multiple transsphenoidal surgeries (TSSs) or radiosurgery. Even experts face difficulties in detecting these recurrent tumors, and a favorable surgical outcome is not guaranteed. In this report, the authors aimed to determine the usefulness of 11C-methionine positron emission tomography (MET-PET) for evaluating patients with recurrent CD with inconclusive magnetic resonance imaging (MRI) lesions and to develop a treatment protocol for these cases. In this retrospective study of patients with recurrent CD in the period between April 2018 and December 2022, the authors assessed the usefulness of MET-PET in determining whether equivocal MRI findings were recurrent tumors or postsurgical cavities and deciding further treatment options. All patients had undergone at least one TSS, and most had undergone multiple TSSs and had pathologically confirmed corticotroph tumors with hypercortisolemia. Overall, 15 patients with recurrent CD (10 females and 5 males) were included, all of whom had undergone MET-PET. All patients had been subjected to multiple treatments, including TSSs or radiosurgeries. Their MRI scans demonstrated less-enhanced lesions that were not confirmed as recurrences even with cutting-edge MRI because they could not be distinguished from postsurgical changes with confidence. MET uptake was positive in 8 patients (9 examinations) and negative in 7. Following MET-PET, repeat TSS was performed in 5 patients. Corticotroph tumors were identified in all 5 patients, even though one of them had negative MET uptake. The MET uptake precisely identified a tumor location on the opposite side of the MRI-suspected lesion in 2 patients. Meanwhile, patients with negative uptake and mild hypercortisolism were only observed. Nonsurgical options were also used in other patients: temozolomide (TMZ) was administered in 2 patients owing to a prior history of multiple TSSs and radiosurgery and the drug-resistant nature of the disease. TMZ was highly effective in these patients; their Cushing's symptoms ameliorated, and their adrenocorticotropic hormone and cortisol levels continued to decline. Interestingly, MET uptake disappeared following TMZ treatment. MET-PET is extremely useful for confirming equivocal lesions on MRI in patients with recurrent CD and for deciding further treatment options. The authors propose a novel protocol based on MET-PET results for treating patients with relapsing CD in whom the recurrent tumors cannot be confirmed with MRI.

Analysis of Discordant Findings between 3T Magnetic Resonance Imaging and Arthroscopic Evaluation of the Knee Meniscus.

Numerous studies have assessed the performance of magnetic resonance imaging (MRI) in detecting tears of the knee menisci using arthroscopy results as the gold standard, but few have concentrated on the nature of discordant findings. The purpose of this study was to analyze the discordances between 3T MRI and arthroscopic evaluation of the knee meniscus. Medical records of 112 patients who underwent 3T MRI and subsequent arthroscopy of the knee were retrospectively analyzed to determine the accuracy of diagnoses of meniscal tear. Compared with arthroscopy, there were 22 false-negative and 14 false-positive MR interpretations of meniscal tear occurring in 32 patients. Images with errors in diagnosis were retrospectively reviewed by two musculoskeletal radiologists in consensus and all errors were categorized as either unavoidable, equivocal or as interpretation error. Of 36 MR diagnostic errors, there were 16 (44%) unavoidable, 5 (14%) interpretation errors and 15 (42%) equivocal for meniscal tear. The largest categories of errors were unavoidable false-positive MRI diagnoses (71%) and equivocal false-negative MRI diagnoses (50%). All meniscal tears missed by MRI were treated with partial meniscectomy (n = 14) or meniscal repair (n = 8). Discordant findings between 3T MRI and arthroscopic evaluation of the knee meniscus remain a concern and primarily occur due to unavoidable and equivocal errors. Clinicians involved in the diagnosis and treatment of patients with meniscal tears should understand why and how the findings seen on knee MRI and arthroscopy may sometimes differ.

Prediction of significant prostate cancer in equivocal MRI lesions: A high-volume international multicenter study.

311 Background: The decision of performing prostate biopsy in men with equivocal findings in prostate magnetic resonance imaging (MRI) is challenging as they have a low but still relevant risk of harboring significant prostate cancer (sPC). Objective: To identify clinical predictors of sPC in men with equivocal findings in prostate MRI. Secondly, we aimed to analyze the hypothetical effect of incorporating prostate-specific antigen density (PSAD) into biopsy decision. Methods: We analysed a retrospective multinational cohort from 10 academic centers comprising 1476 men who underwent combined prostate biopsy (MRI-targeted plus systematic) between 02/2012 – 04/2021 due to an equivocal lesion found in prostate MRI (Prostate Imaging Reporting and Data System 3). Primary outcome was the detection of sPC (ISUP ≥ 2) in combined biopsy. Regression analysis was performed to identify predictors for this outcome. Descriptive statistics were applied to evaluate the hypothetical effect of involving PSAD into biopsy decision. Results: 273/1476 (18.5%) men were diagnosed with sPC by combined biopsy. MRI-targeted biopsy diagnosed less sPC as compared to combined strategy: 183/1476 (12.4%) vs. 273/1476 (18.5%), p<0.01. Regression analysis confirmed age (OR 1.10 [95% CI: 1.05 – 1.15]; p < 0.001), prior negative biopsy (OR 0.46 [0.24 – 0.89]; p = 0.022) and PSAD (p<0.001) as independent predictors for sPC. Applying a PSAD cut-off of 0.15 for biopsy decision, 817/1398 (58.4%) of the biopsy procedures would have been avoided at the cost of missing sPC in 91 (6.5%) men. Limitations were the retrospective design, heterogeneity of the study cohort due to the long inclusion period and a missing central revision of MRI. Conclusions: Age, previous biopsy status and PSAD were found independent predictors of sPC in men with equivocal prostate MRI. Implementation of PSAD into biopsy decision can avoid a large proportion of unnecessary biopsies. Clinical parameters such as PSAD need validation in a prospective setting.

Prediction of Significant Prostate Cancer in Equivocal Magnetic Resonance Imaging Lesions: A High-volume International Multicenter Study

BackgroundDecision of performing prostate biopsy in men with Prostate Imaging Reporting and Data System (PI-RADS) 3 findings in prostate magnetic resonance imaging (MRI) is challenging as they have a low but still relevant risk of harboring significant prostate cancer (sPC). ObjectiveTo identify clinical predictors of sPC in men with PI-RADS 3 lesions in prostate MRI and to analyze the hypothetical effect of incorporating prostate-specific antigen density (PSAD) into biopsy decision. Design, setting, and participantsWe analyzed a retrospective multinational cohort from ten academic centers comprising 1476 men who underwent a combined prostate biopsy (MRI targeted plus systematic biopsy) between February 2012 and April 2021 due to a PI-RADS 3 lesion in prostate MRI. Outcome measurements and statistical analysisThe primary outcome was the detection of sPC (ISUP ≥2) in a combined biopsy. Predictors were identified by a regression analysis. Descriptive statistics were applied to evaluate the hypothetical effect of involving PSAD into biopsy decision. Results and limitationsOf all patients, 273/1476 (18.5%) were diagnosed with sPC. MRI-targeted biopsy diagnosed fewer sPC cases than combined strategy: 183/1476 (12.4%) versus 273/1476 (18.5%), p < 0.01. Age (odds ratio [OR] 1.10 [95% confidence interval {CI}: 1.05–1.15], p < 0.001), prior negative biopsy (OR 0.46 [0.24–0.89], p = 0.022), and PSAD (p < 0.001) were found to be independent predictors of sPC. Applying a PSAD cutoff of 0.15, 817/1398 (58.4%) biopsies would have been avoided at the cost of missing sPC in 91 (6.5%) men. Limitations were the retrospective design, heterogeneity of the study cohort due to the long inclusion period, and no central revision of MRI. ConclusionsAge, previous biopsy status, and PSAD were found to be independent predictors of sPC in men with equivocal prostate MRI. Implementation of PSAD into biopsy decision can avoid unnecessary biopsies. Clinical parameters such as PSAD need validation in a prospective setting. Patient summaryIn this study, we looked for clinical predictors of significant prostate cancer in men with Prostate Imaging Reporting and Data System 3 lesions in prostate magnetic resonance imaging. We identified age, previous biopsy status, and especially prostate-specific antigen density as independent predictors.

P15.10.B A multicenter phase 3 trial in progress: diagnostic performance of18F-fluciclovine PET for the detection of recurrent brain metastases after radiation therapy (REVELATE)

Abstract Background Following treatment of brain metastases, which can affect up to 40% of patients with cancer, patients will typically be closely monitored with serial brain magnetic resonance imaging (MRI) owing to the high likelihood of recurrence. The recommended follow-up modalities (CE-T1-weighted and FLAIR/T2-weighted MRI) have poor specificity, meaning that differentiation of true disease from treatment-related changes such as radiation necrosis can be difficult. Recent pilot studies have reported amino acid PET radiopharmaceutical, 18F-fluciclovine, to be potentially useful in discriminating brain tumor recurrence from treatment-related changes. This may potentially help physicians to make confident diagnoses and inform subsequent treatment plans. Material and Methods REVELATE (NCT04410133) will evaluate the diagnostic performance of 18F-fluciclovine PET (read with conventional MRI for anatomical reference) for the detection of recurrent brain metastases in patients for whom MRI is equivocal. This multicenter, phase 3, prospective, open-label trial aims to enroll approximately 150 subjects from across 19 US sites with solid tumor brain metastases who have undergone radiation therapy, if they have a lesion considered equivocal on MRI that requires further confirmatory diagnostic procedures (either biopsy/neurosurgical intervention or clinical follow-up). Patients will undergo 18F-fluciclovine PET &amp;lt;42 days after the equivocal MRI and 1-21 days pre-biopsy/neurosurgical intervention. Clinical follow-up will occur for 6m post-18F-fluciclovine PET. Results The primary endpoint of REVELATE is the subject-level 18F-fluciclovine negative and positive percent agreement (equivalent to specificity and sensitivity, respectively) for detection of recurrent brain metastases. Further objectives include evaluation of the lesion-level diagnostic performance, inter-reader and intra-reader agreement, and safety evaluations. Conclusion This ongoing phase 3 study will provide efficacy and safety data for the use of 18F-fluciclovine for the detection of recurrent brain metastases. Enrolment began in October 2020 and the trial is active but not recruiting at the time of submission.

NEIM-03 A MULTICENTER PHASE 3 TRIAL IN PROGRESS: DIAGNOSTIC PERFORMANCE OF18F-FLUCICLOVINE PET FOR THE DETECTION OF RECURRENT BRAIN METASTASES AFTER RADIATION THERAPY (REVELATE)

INTRODUCTIONFollowing treatment of brain metastases, which can affect up to 40% of patients with cancer, patients will typically be closely monitored with serial brain magnetic resonance imaging (MRI) owing to the high likelihood of recurrence. The recommended follow-up modalities (CE-T1-weighted and FLAIR/T2-weighted MRI) have poor specificity, meaning that differentiation of true disease from treatment-related changes such as radiation necrosis can be difficult. Recent pilot studies have reported amino acid PET radiopharmaceutical, 18F-fluciclovine, to be potentially useful in discriminating tumor recurrence from treatment-related changes. This may potentially aid physicians in making confident diagnoses and inform subsequent treatment plans. METHODSREVELATE (NCT04410133) will evaluate the diagnostic performance of 18F-fluciclovine PET (read with conventional MRI for anatomical reference) for the detection of recurrent brain metastases in patients for whom MRI is equivocal. This multicenter, phase 3, prospective, open-label trial aims to enroll approximately 150 subjects from across 19 US sites with solid tumor brain metastases who have undergone radiation therapy, if they have a lesion considered equivocal on MRI that requires further confirmatory diagnostic procedures (either biopsy/neurosurgical intervention or clinical follow-up). Patients will undergo 18F-fluciclovine PET <42 days after the equivocal MRI and 1–21 days pre-biopsy/neurosurgical intervention. Clinical follow-up will occur for 6m post-18F-fluciclovine PET. Secondary objectives include evaluation of subject- and lesion-level 18F-fluciclovine negative and positive percent agreement (equivalent to specificity and sensitivity, respectively) for recurrent brain metastases, inter-reader and intra-reader agreement, and safety evaluations. Enrolment began in October 2020 and the trial is active but not recruiting at the time of submission.

Clinical suspicion of spondylodiscitis with equivocal MRI findings: does diffusion-weighted imaging prove helpful here?

Despite the high sensitivity of magnetic resonance imaging (MRI), early detection of spondylodiscitis (SpD) remains challenging due to its low specificity. To assess the diagnostic value of diffusion-weighted imaging (DWI) in suspected cases of SpD with ambiguous early MRI findings in the differentiation of degenerative disorders (DD). In this prospective study, 52 patients suspected of having SpD underwent a whole-spine 3-T MRI scan comprising sagittal DWI. Of 58 conspicuous, T2-weighted, signal increased discs, 39 were successfully evaluated using DWI. Apparent diffusion coefficient (ADC) values and ADC maps were blindly analyzed using the region of interest of the conspicuous disc and a normal adjacent reference disc. Intraindividual ratios (conspicuous disc: reference disc) were calculated. All conspicuous discs showed increased absolute ADC values, which did not differ significantly between SpD (n = 22) and DD (n = 17). However, ADC ratio was significantly higher in SpD vs. DD (P < 0.05). In receiver operating characteristic curve analysis, an ADC ratio threshold of 1.6 resulted in 45% sensitivity and 88% specificity (area under the curve = 0.69) for SpD diagnosis. The absolute ADC value does not provide a reliable diagnosis of SpD. Increased diffusivity can be an indication of infection but should always be discussed in the context of existing disc degeneration.

Alvarado Scores Predict Additive Value of Magnetic Resonance Imaging in Workup of Suspected Appendicitis in Children

BackgroundThe presentation of appendicitis in pediatrics is variable, and diagnostic imaging is often used. Magnetic resonance imaging (MRI) is replacing computed tomography in some centers, particularly after a nondiagnostic ultrasound (NDUS). Nonetheless, MRI is not widely used in this setting because of cost, procedure time, institutional capacity, and high rates of negative scans. We hypothesized that the Alvarado Score (AS) could be used to determine the additive diagnostic value of MRI after an NDUS. Materials and methodsRetrospective review of patients aged ≤18 y at a single tertiary care children's hospital who received an ultrasound for suspected appendicitis during 10 consecutive months in 2017. NDUS were defined as nonvisualization of the appendix or secondary signs without radiologic diagnosis. AS were retrospectively calculated from the electronic medical record. Primary outcomes were pathology-confirmed appendicitis, appendectomy, and perforation. ResultsAS was determined for 352 patients out of 463 who met inclusion criteria (76%). Sixty-two percent had an NDUS, and 45% of these patients received MRI. Patients with high-risk AS were significantly more likely to have MRI diagnostic of appendicitis (P = 0.0015), and low-risk AS patients were more likely to have a negative or equivocal MRI (P = 0.0169). Twenty-one MRI scans were required per each additional diagnosis of appendicitis in patients with low AS after NDUS versus 4.2 in intermediate-risk AS patients and 2.1 in high-risk AS patients. ConclusionsRisk stratification with AS can help assess the additive diagnostic utility of MRI after NDUS. MRI may be overutilized for diagnosing acute appendicitis in pediatric patients with low-risk AS.

A comparative study of MRI versus arthroscopic findings in ACL and meniscal injuries of the knee

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; &lt;span lang="EN-IN"&gt;This study was conducted to compare accuracy of MRI findings taking arthroscopy as standard in knee injuries.&lt;/span&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; &lt;span lang="EN-IN"&gt;All patients attending our hospital with knee injury underwent clinical examination. Out of them 100 patients with knee injury were subjected to clinical examination, MRI and then Arthroscopy. The results were compared and analyzed using various statistical tests. The accuracy, sensitivity and specificity were calculated based on these arthroscopic and MRI findings&lt;/span&gt;.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; &lt;span lang="EN-IN"&gt;The accuracy of clinical diagnosis in our study was 88% for ACL tears and 85% for meniscal tears. Our study proved high sensitivity and specificity and almost high accuracy for ACL injuries of knee joint in comparison to arthroscopy. MRI is an excellent screening tool for therapeutic arthroscopy. We can avoid diagnostic arthroscopy in patients with knee injuries having equivocal clinical and MRI examination and go on for therapeutic modality. &lt;/span&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; &lt;span lang="EN-IN"&gt;For the assessment of ligamentous and meniscal injuries magnetic resonance imaging (MRI) is accurate and noninvasive modality. It can be used as a first line investigation but arthroscopy still remains gold standard in diagnosing ACL and meniscal injuries.&lt;/span&gt;&lt;/p&gt;&lt;p class="abstract"&gt; &lt;/p&gt;

Predictors of residual disease after unplanned excision of soft tissue sarcomas

BackgroundUnplanned excision of soft tissue sarcomas (STS) is an important quality of care issue given the morbidity related to tumor bed excision. Since not all patients harbor residual disease at the time of reexcision, we sought to determine predictors of residual STS following unplanned excision. MethodsWe identified 76 patients from a prospective database (January 1, 2008-September 30, 2014) who received a diagnosis of primary STS following unplanned excision on the trunk or extremities. We used univariable and multivariable analyses to evaluate predictors of residual STS as the primary endpoint. We calculated the sensitivity, specificity, and accuracy of interval magnetic resonance imaging (MRI) to predict residual sarcoma at reexcision. ResultsMean age was 52 y, and 63.2% were male. 50% had fragmented unplanned excision. Among patients undergoing reexcision, residual STS was identified in 70%. On univariable analysis, MRI showing gross disease and fragmented excision were significant predictors of residual STS (odds ratio, 10.59; 95% CI, 2.14-52.49; P = 0.004 and odds ratio, 3.61; 95% CI, 1.09-11.94; P = 0.035, respectively). On multivariable analysis, tumor size predicted distant recurrence and overall survival. When we combined equivocal and positive MRI, the sensitivity and specificity of MRI for predicting residual STS were 86.7% (95% CI, 73.2%-95.0%) and 57.9% (95% CI, 33.5%-79.8%), with an overall accuracy of 78.1% (95% CI, 66.0%-87.5%). ConclusionsAbout 70% of patients undergoing repeat excision after unplanned excision of STS harbor residual sarcoma. Although interval MRI and fragmented excision appear to be the most significant predictors of residual STS, the accuracy of MRI remains modest, especially given the incidence of equivocal MRI.

Venous Sampling for Cushing Disease: Comparison of Internal Jugular Vein and Inferior Petrosal Sinus Sampling

Because magnetic resonance imaging (MRI) fails to detect many adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas, inferior petrosal sinus sampling (IPSS) is considered the gold standard to differentiate Cushing disease (CD) from ectopic ACTH secretion syndrome (EAS). Some authors have suggested internal jugular vein sampling (IJVS) as an alternative to IPSS. We simultaneously compared IJVS to IPSS in 30 consecutive patients referred for ACTH-dependent Cushing syndrome and equivocal MRI exams. Five sites were simultaneously sampled in each patient (right and left IPS, right and left IJV, and femoral vein) before and after the administration of corticotrophin-releasing hormone or desmopressin. The test was considered consistent with CD when the IPS to peripheral ratio was >2 at baseline or >3 after stimulus and the IJV to peripheral ratio was >1.7 at baseline or >2 after stimulus. In 27 of 30 patients, IPSS results were consistent with a central source of ACTH. Two of the other 3 patients had EAS (one lung carcinoid and one occult), and 1 patient had pathology-proven CD. The sensitivity of IPSS was 96.4%. Only 64.2% of these patients had results meeting criteria for a central source of ACTH by IJVS criteria. Twenty patients with centralizing IPPS have undergone pituitary surgery. Of these, the central origin of excessive ACTH was confirmed with certainty in 16 patients. Among these 16 patients, the IPSS sensitivity was 93.8%, whereas 5 patients had false-negative IJVS (68.7% sensitivity). These results do not support the routine use of IJVS in establishing if the pituitary is the source of excessive ACTH. ACTH = adrenocorticotropic hormone CD = Cushing disease CRH = corticotrophin-releasing hormone CS = Cushing syndrome DDAVP = desmopressin EAS = ectopic ACTH secretion IJVS = internal jugular vein sampling IPSS = inferior petrosal sinus sampling JVS = jugular venous sampling MRI = magnetic resonance imaging.

Ectopic Acth-Secreting Syndrome: A Single-Center Experience

ObjectiveEctopic adrenocorticotropic hormone (ACTH)-secreting syndrome (EAS) is a rare cause of ACTH-dependent endogenous hypercortisolism. The objective of this study was to analyze clinical, biochemical, and imaging characteristics; management strategies; and outcomes of EAS patients. MethodWe screened the records (1993-2012) of ACTH-dependent endogenous hypercortisolism cases managed at a tertiary care center. ResultsOf the 218 patients, 17 were diagnosed with EAS. The median 8:00 AM serum cortisol was 36 μg/dL (11.4-82.7 μg/dL), and the median basal plasma ACTH was 156 pg/mL (53.5-468 pg/mL). Notably, ACTH levels below 100 pg/mL were found in 4 patients. Suspicious microadenoma was found on magnetic resonance imaging (MRI) of the pituitary in 5 patients, and all of them underwent transsphenoidal surgery (TSS). Inferior petrosal sinus sampling (IPSS) was performed in 8 patients, and the results were suggestive of a peripheral source in all 8. Computed tomography (CT) localized the lesion in 15/17 patients. In 2 patients with negative CTs, gallium DOTATATE positron emission tomography (PET) scans localized the lesion. Despite difficulties localizing bronchial carcinoids, the cure rate was high (72%). In contrast, thymic carcinoids were easily localized but had poor outcomes. ConclusionEAS cannot be ruled out on the basis of marginally elevated ACTH. In cases with an equivocal MRI pituitary finding, prior IPSS can help avoid unnecessary TSS. CT is a useful modality for localization of an ectopic source. Functional imaging may help in cases where anatomical imaging fails. (Endocr Pract. 2013;19:1007-1014)

Efficacy of Magnetic Resonance Imaging in Diagnosing Diabetic Foot Osteomyelitis in the Presence of Ischemia

Magnetic resonance imaging (MRI) has been recognized as the most accurate imaging modality for the detection of diabetic foot osteomyelitis. However, how accurately MRI displays the extent of diabetic foot osteomyelitis in the presence of ischemia is still unclear. We retrospectively compared the preoperative MRI findings with the results of histopathologic examinations of resected bones and studied the efficacy of MRI in the diagnosis of diabetic foot osteomyelitis of different etiologies. A total 104 bones from 18 foot ulcers in 16 diabetic patients (10 men and 6 women; age range 42 to 84 years) treated by surgical intervention from 2008 to 2012 was examined. In 8 neuropathic ulcers, 29 bones were accurately diagnosed in detail using MRI, even those with severe soft tissue infection. Of 75 bones in 10 ischemic ulcers, only 7 bones evaluated by MRI after revascularization were diagnosed accurately; the other 68 could not be diagnosed because of unclear or equivocal MRI findings. On histopathologic examination, all the bones were found to be infected through the bone cortex by the surrounding infected soft tissue, not directly by articulation. Overall, preoperative MRI is effective in the diagnosis of neuropathic ulcers, but less so of ischemic ones.

The evaluation of FDG-PET imaging for epileptogenic focus localization in patients with MRI positive and MRI negative temporal lobe epilepsy

We studied the contribution of interictal FDG-PET ([18F] fluorodeoxyglucose-positron emission tomography) in epileptic focus identification in temporal lobe epilepsy patients with positive, equivocal and negative magnetic resonance imaging (MRI). Ninety-eight patients who underwent surgical treatment for drug resistant temporal lobe epilepsy after neuropsychological evaluation, scalp video EEG monitoring, FDG-PET, MRI and/or long-term intracranial EEG and with >12months clinical follow-up were included in this study. FDG-PET findings were compared to MRI, histopathology, scalp video EEG and long-term intracranial EEG monitoring. FDG-PET lateralized the seizure focus in 95% of MRI positive, 69% of MRI equivocal and 84% of MRI negative patients. There was no statistically significant difference between the surgical outcomes among the groups with Engel class I and II outcomes achieved in 86%, 86%, 84% of MRI positive, equivocal and negative temporal lobe epilepsy patients, respectively. The patients with positive unilateral FDG-PET demonstrated excellent postsurgical outcomes, with 96% Engel class I and II. Histopathology revealed focal lesions in 75% of MRI equivocal, 84% of MRI positive, and 23% of MRI negative temporal lobe epilepsy cases. FDG-PET is an accurate noninvasive method in lateralizing the epileptogenic focus in temporal lobe epilepsy, especially in patients with normal or equivocal MRIs, or non-lateralized EEG monitoring. Very subtle findings in MRI are often associated with histopathological lesions and should be described in MRI reports. The patients with negative or equivocal MRI temporal lobe epilepsy are good surgical candidates with comparable postsurgical outcomes to patients with MRI positive temporal lobe epilepsy.

Magnetic resonance imaging findings in 40 dogs with histologically confirmed intracranial tumours

Magnetic resonance (MR) images of 40 dogs with histologically confirmed primary and secondary intracranial tumours were reviewed. Forty-one tumours were diagnosed by means of MR imaging (MRI). MRI findings allowed diagnosis of a neoplastic lesion in 37/41 cases. Based on MRI features, differentiation between neoplastic and non-neoplastic lesions was possible in 24/27 (89%) primary brain tumours and in 13/14 (92%) secondary brain tumours. Diagnosis of tumour type based on MRI features was correct in 19/27 (70%) primary tumours and in 13/14 secondary tumours. The results of this study show that MRI is a good diagnostic imaging modality to detect neoplastic lesions and to diagnose tumour type in dogs. However, as some neoplasms show equivocal MRI features the technique has limitations in the detection of some intracranial tumours and in predicting tumour type.

3T versus 1.5T phased‐array MRI in the presurgical work‐up of patients with partial epilepsy of uncertain focus

To study 3T compared to 1.5T phased array magnetic resonance imaging (MRI) in the presurgical work-up of patients with epilepsy with complex focus localization. In all, 37 patients (>10 years) in preoperative work-up for epilepsy surgery were offered 3T in addition to 1.5T MRI if ambiguity existed about the epileptic focus. Scans were randomly reviewed by two observers, blinded for prior imaging, patient-identifying information, and each other's assessments, followed by a consensus meeting. The number of abnormal scans, detected lesions, and interobserver agreement were calculated and compared. The final consensus was compared to original scan reports. One observer identified 22 lesions in both 3 and 1.5T scans, while the second identified more lesions in 1.5T scans (28 vs. 20). 3T MRI had better interobserver agreement. 3T revealed more dysplasias, while 1.5T revealed more tissue loss and mesial temporal sclerosis (MTS). The final consensus yielded 29 lesions, whereas original reports identified only 17 lesions. The 3T scans revealed different lesions compared to 1.5T. Patients can benefit most from 3T scans when a dysplasia is suspected. Reevaluation by another experienced neuroradiologist is advised in case of negative or equivocal MRIs.

111In-Pentetreotide scintigraphy in medulloblastoma: A comparison with magnetic resonance imaging

Medulloblastoma (MB) is a primitive neuroectodermal tumour constituting a grade IV brain malignancy. Early and correct detection of recurrence or metastasis is desirable for follow-up of patients in this entity. Frequent expression of somatostatin receptors by MB lesions facilitates functional tumour imaging by somatostatin receptor scintigraphy (SRS). To investigate the value of SRS in the follow-up of MB, the results of ten consecutive patients (seven children and three adults) undergoing additional imaging with 111In-pentetreotide were reviewed. Four, 24 and 48 h p.i. planar and whole body images as well as a SPECT study at 4 h p.i. were acquired after intravenous injection of 109±35 MBq 111In-pentetreotide (Octreoscan®). SRS yielded 11 positive and ten negative imaging results, compared to 17 positive and four negative in magnetic resonance imaging (MRI). The lesion-by-lesion analysis with a total of 44 lesions revealed a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 42%, 83%, 94%, 18% for SRS and 89.5%, 50%, 92%, 43% for MRI. Based on a per-patient analysis, considering the patient as to be either tumour-free or tumour-positive by one imaging modality, the following values for sensitivity, specificity, PPV and NPV were obtained: 61%, 100%, 100%, 30% for SRS and 94%, 67%, 94%, 67% for MRI. MRI remains the first step imaging technique in medulloblastoma patients before and after surgery and during the follow-up providing the highest sensitivity. However, to improve specificity and contribute to correct diagnosis in MB 111In-pentetreotide scintigraphy should be considered as a confirmatory second step imaging tool, especially in case of equivocal MRI results. Moreover, a positive SRS scan might serve as a reference before and after somatostatin receptor targeted radiotherapy.

The distended facet sign: an indicator of position-dependent spinal stenosis and degenerative spondylolisthesis

Background context Symptoms of spinal stenosis are position-dependent. Stand up magnetic resonance imaging (MRI) and myelography can demonstrate further dynamic components of spinal stenosis that may go unrecognized on supine MRI. Purpose To describe a radiographic finding seen on standard supine MRI that is an indicator for dynamic spinal stenosis and degenerative spondylolisthesis. Study design/setting Case series. Patient sample Six patients. Outcomes measures Radiographic observation. Methods Six patients with classic neurogenic claudication but equivocal supine MRI findings were evaluated with myelography. The imaging findings were reviewed and compared. Results All patients had severe position-dependent spinal stenosis upon upright myelographic imaging with grade I or II spondylolisthesis. The MRI showed very minimal to no spondylolisthesis. These dynamic slips reduced when supine, causing the vertebral bodies to appear aligned with adequate canal space, whereas the irregular facet joints became distended. Hypertrophic and fluid-filled facets at the dynamic slip level were seen in all patients, giving the appearance of a distended joint. Conclusions MRI may not demonstrate significant stenosis in patients with neurogenic claudication caused by dynamic degenerative spondylolisthesis. However, the presence of large fluid-filled facet joints indicates the likelihood of positional translation at that level which could be further confirmed by upright imaging.

Magnetic Resonance Imaging of Bone Marrow Versus Bone Marrow Biopsy in Malignant Lymphoma

Bone marrow involvement is a frequent finding in malignant lymphoma. Bone marrow biopsy of the posterior iliac crest is routinely performed for staging. Abnormal magnetic resonance imaging (MRI) signals of bone marrow was also reported to be indicative of bone marrow involvement. This study included 60 patients with malignant lymphoma. Unilateral bone marrow biopsy of the posterior iliac crest was performed. MRI of lumbar spine was studied within 24 hours of bone marrow biopsy. 22 healthy controls were used for the detection of MRI objectivity during visual evaluation. In 83% of patients (50/60), biopsy and MRI results agreed completely. In two patients, histologic sections failed to show any evidence of bone marrow involvement despite abnormal MRI signals suggestive of involvement. In three patients, MRI was completely normal despite biopsy proven bone marrow infiltration. False negativity (3/60) and false positivity (2/60) rates were very low. Negative biopsy findings with positive or equivocal MRI results should not exclude bone marrow involvement and need further evaluation with bilateral or guided biopsy. Thus, we conclude that MRI of bone marrow is a fairly sensitive, noninvasive modality and might be of potential value in detecting bone marrow infiltration in malignant lymphoid neoplasms which can be utilized as a useful adjunct to standard staging procedures. Copyright 1999 W.B. Saunders Company Ltd on behalf of the Arányi Lajos Foundation

Brain structure and neurocognitive and behavioural function in adolescents who were born very preterm

Infants born very preterm (<33 weeks) are at increased risk of neurocognitive deficits. Their neurodevelopmental outcome up to age 8 years can be predicted by neonatal ultrasonography, but little is known of their later function. We investigated the effect of very preterm birth on brain structure and neurocognitive and behavioural functioning in adolescence. A cohort of 105 infants born before 33 weeks of gestation in 1979-80 had ultrasonographic scans at University College Hospital, London, and were prospectively examined at 1, 4, and 8 years. At age 14-15 years, 72 of those who remained in UK (cases) and 21 age-matched full-term controls underwent brain magnetic resonance imaging (MRI), as well as neurological, cognitive, and behavioural assessment. MRI images were assessed by two neuroradiologists unaware of ultrasonographic findings or case or control status. Of the 72 cases, 40 had unequivocally abnormal MRI and 15 had equivocal scans. Of the 21 controls, one had abnormal and five equivocal MRI. Abnormalities of ventricles, corpus callosum, and white matter were especially common in cases. More brain lesions were identified by MRI than by neonatal ultrasonography. The cases had significantly more reading, adjustment, and neurological impairments than controls, but their behaviour was significantly related to MRI abnormality. Individuals born very preterm show an excess of neurocognitive and behavioural problems in adolescence, and more than half have abnormal MRI brain scans.