Short-term Follow-up Magnetic Resonance Imaging Research Articles

Cerebral sparganosis in a child with corpus callosum invasion: a case report

BackgroundInvasion of the corpus callosum by sparganosis is rare in children. After invading the corpus callosum, sparganosis has various migration modes, which can break through the ependyma and enter the ventricles, thus causing secondary migratory brain injury.Case presentationA girl aged 4 years and 7 months presented with left lower limb paralysis for more than 50 days. Blood examination showed that the proportion and absolute number of eosinophils in the peripheral blood were increased. Furthermore, enzyme-linked immunosorbent assay of serum and cerebrospinal fluid samples revealed positivity for IgG and IgM antibodies for sparganosis. Initial magnetic resonance imaging (MRI) revealed ring-like enhancements in the right frontoparietal cortex, subcortical white matter, and splenium of the corpus callosum. Within 2 months, a fourth follow-up MRI showed that the lesion had spread to the left parietal cortex, subcortical white matter, and deep white matter in the right occipital lobe and right ventricular choroid plexus, with left parietal leptomeningeal enhancement.ConclusionMigratory movement is one of the characteristics of cerebral sparganosis. When sparganosis invades the corpus callosum, clinicians should be aware that it may then break through the ependyma and enter the lateral ventricles, leading to secondary migratory brain injury. Short-term follow-up MRI is necessary to evaluate the migration mode of sparganosis and dynamically guide treatment strategies.

Diagnostic Performance of and Breast Tissue Changes at Early Breast MR Imaging Surveillance in Women after Breast Conservation Therapy.

Purpose To investigate the diagnostic performance and tissue changes in early (1 year or less) breast magnetic resonance (MR) imaging surveillance in women who underwent breast conservation therapy for breast cancer. Materials and Methods This prospective study was approved by the institutional review board, and written informed consent was obtained. Between April 2014 and June 2016, 414 women (mean age, 51.5 years; range, 21-81 years) who underwent 422 early surveillance breast MR imaging examinations (median, 6.0 months; range, 2-12 months) after breast conservation therapy were studied. The cancer detection rate, positive predictive value of biopsy, sensitivity, specificity, accuracy, and area under the curve of surveillance MR imaging, mammography, and ultrasonography (US) were assessed. Follow-up was also obtained in 95 women by using positron emission tomography (PET)/computed tomography (CT). Background parenchymal enhancement (BPE) changes in the contralateral breast were assessed according to adjuvant therapy by using the McNemar test. Results Of 11 detected cancers, six were seen at MR imaging only, one was seen at MR imaging and mammography, two were seen at MR imaging and US, one was seen at mammography only, and one was seen at PET/CT only. Three MR imaging-depicted cancers were observed at the original tumor bed, and two MR imaging-depicted cancers were observed adjacent to the original tumor. Among two false-negative MR imaging diagnoses (two cases of ductal carcinoma in situ), one cancer had manifested as calcifications at mammography without differentiated enhancement at MR imaging, and the other cancer was detected at PET/CT, but MR imaging results were negative because of marked BPE, which resulted in focal lesion masking. The positive predictive value of biopsy and the sensitivity, specificity, accuracy, and area under the curve for MR imaging were 32.1% (nine of 28), 81.8% (nine of 11), 95.1% (391 of 411), 94.7% (400 of 422), and 0.88, respectively. The sensitivity of surveillance MR imaging (81.8%; 95% confidence interval [CI]: 48.2%, 97.7%) was higher than that of mammography (18.2%; 95% CI: 2.3%, 51.8%) and US (18.2%; 95% CI: 2.3%, 51.8%), with an overlap in CIs. The BPE showed a significant decrease in the group of patients who received adjuvant chemotherapy (43 BPE decreases and four BPE increases) and the group of patients who received hormone therapy (55 BPE decreases and two BPE increases) (P < .0001 for both). Conclusion Early MR imaging surveillance after breast conservation therapy can be useful in patients who have breast cancer, with superior sensitivity compared with that of mammography and US. The BPE tends to be decreased at short-term follow-up MR imaging in patients who receive adjuvant therapy. © RSNA, 2017.

Role of short-term follow-up magnetic resonance imaging in the detection of post-operative residual breast cancer.

The aim of the present study was to evaluate the role of short-term follow-up magnetic resonance imaging (MRI) in the detection of postoperative residual breast cancer. A retrospective analysis was performed on 10 patients who were diagnosed with non-malignant breast lesions by preoperative clinical, ultrasound and mammography examinations and intraoperative frozen-section pathology. These patients were finally confirmed as having malignant breast lesions by paraffin-embedded tissue histology and corresponding received second surgeries. Routine MRI, enhancement MRI and echo-planar imaging-diffusion-weighted imaging were performed on the 10 patients within 1 month after the first surgery. All the cases showed a local distortion of mammary architecture revealed by routine MRI and enhancement MRI images. The enhancement characteristics of the 10 cases were as follows: 3 cases featured stippled enhancement, 2 had small nodular enhancement, 1 showed dendritic enhancement, 1 had a ring-shaped enhancement of the cystic wall and 3 had no abnormal enhancement. The lesions of 7 cases had a type-I enhancement curve (progressive enhancement pattern) and 3 cases had a type-II curve (plateau pattern). The lesions of 4 cases had a decreased apparent diffusion coefficient. In total, 4 cases of tumor residue were diagnosed by MRI and the second pathological examination, while in 1 case the tumor residue was misdiagnosed by MRI but confirmed by the second pathological examination. In conclusion, the present study suggested that short-term follow-up MRI may be of value in the diagnosis of postoperative residual breast tumors and may be helpful for surgeons to develop an accurate surgical plan.

MR imaging-guided vacuum-assisted breast biopsy: Reduction of false-negative biopsies by short-term control MRI 24–48 h after biopsy

To evaluate whether another contrast-enhanced (CE) magnetic resonance imaging (MRI) examination 24-48h after MRI-guided vacuum-assisted breast biopsy (MRI-VAB) can reduce the rate of false-negative cases. The study included 252 patients who underwent MRI-VAB for the clarification of 299 lesions. The success of MRI-VAB was assessed at interventional MRI and another CE MRI 24-48h after the intervention. In cases of successful MRI-VAB (complete or partial lesion removal) and benign histological results, follow-up breast MRI was performed. In cases of unsuccessful biopsy (unchanged lesion), tissue sampling was repeated. False-negative cases were calculated to assess the diagnostic value of MRI follow-up within 2 days after intervention. Ninety-eight malignant (32.8%) and 201 (67.2%) benign lesions were diagnosed using MRI-VAB. At immediate unenhanced control MRI, all lesions were assessed as successfully biopsied. In 18 benign cases (6%), CE MRI after 24-48h showed an unsuccessful intervention. Further tissue sampling revealed another 13 cancers in these patients. This results in a false-negative rate of 11.7%. Follow-up MRI of the benign lesions presented no further malignancy. MRI-VAB with immediate unenhanced control offers a success rate of 94%. The rate of false-negative biopsies (11.7%) could be reduced to zero by using short-term follow-up MRI. Therefore, a further CE breast MRI 24-48h after benign MRI-VAB to eliminate missed cancers is recommended.

Analyses of short-term follow-up MRI and PET-CT for evaluation of residual tumour after inadequate primary resection of malignant soft-tissue tumours

To differentiate remnant tumour from postoperative changes on short-term follow-up magnetic resonance imaging (MRI) or combined positron-emission tomography (PET) and computed tomography (CT) after inadequate primary resection of malignant soft-tissue tumours. From January 2007 through September 2010, 35 patients (18 women and 17 men; mean age 48 years; age range 18-78 years) who underwent MRI and PET-CT within 64 days after surgery for malignant soft-tissue tumours were included. MRI images were assessed for the following findings: the presence of delineated enhancing portions; fascial thickening; and fluid or haematomas with measurable wall thickening. The PET-CT data were analysed using the standardized uptake value (SUV) and the uptake pattern. The correlation of tumour grade and the presence of remnant tumour was significant (p = 0.026). After re-excision, remnant tumour was demonstrated in 15 patients and no tumour cells were discovered in 20 patients. The finding of focally delineated enhancing portions on MRI images and the SUVmax on PET-CT analysis were significantly correlated with the remnant tumour (each p = 0.001 and p = 0.036). To evaluate the presence of remnant tumour after inadequate excision of malignant soft-tissue tumours, an MRI finding of a focally enhancing area and an SUVmax of >2 on PET-CT might be helpful factors. The coexistence of these two findings would be even more helpful for the detection of residual tumours.

Screening Breast MR Imaging in Women with a History of Lobular Carcinoma in Situ

To assess the utility of screening magnetic resonance (MR) imaging in the detection of otherwise occult breast cancers in women with a history of lobular carcinoma in situ (LCIS). This HIPAA-compliant study received institutional review board approval. The need for informed consent was waived. Retrospective review of the database yielded 670 screening breast MR studies obtained between January 2003 and September 2008 in 220 women with a history of LCIS. MR and mammographic findings were reviewed. Number of cancers diagnosed, method of detection, and tumor characteristics were examined. The cumulative incidence of developing breast cancer as detected with MR imaging and mammography was calculated. Breast density was examined as a prognostic factor in the cumulative incidence analysis. Biopsy was recommended in 63 lesions seen in 58 (9%) of 670 screening MR studies. Eight additional lesions were identified at short-term follow-up MR imaging for a total of 71 lesions in 59 patients. Twelve cancers (20%) were identified in 60 lesions sampled. Biopsy was recommended in 26 additional lesions identified at mammography; biopsy was performed in 25 of these lesions and revealed malignancy in five (20%). Overall, 17 cancers were detected in 14 patients during the study period. Of these, 12 were detected with MR imaging alone, and five were detected with mammography alone. Of the 12 cancers detected at MR imaging, there were nine invasive cancers and three cases of ductal carcinoma in situ (DCIS). Of the five cancers detected at mammography, two were invasive and three were DCIS. MR imaging is a useful adjunct modality with which to screen women with a history of LCIS at high-risk of developing breast cancer, resulting in a 4.5% incremental cancer detection rate. Sensitivity in the detection of breast cancers with a combination of MR imaging and mammography was higher than sensitivity of either modality alone.

Cancellation of MR Imaging–guided Breast Biopsy Due to Lesion Nonvisualization: Frequency and Follow-Up

To determine the rate of canceled magnetic resonance (MR) imaging-guided breast biopsies due to nonvisualization of the lesion and to assess associated features and outcome data for these cases. With the approval of the institutional review board, a HIPAA-compliant retrospective review, in which the requirement for informed consent was waived, was performed for 907 patients scheduled for MR imaging-guided breast biopsy from 2004 to 2008. In 70 patients, MR imaging biopsy was canceled due to lesion nonvisualization. Medical records and imaging studies were reviewed to identify patient, parenchymal, lesion features and outcome data. Statistical analysis was performed with the Fisher exact test. The 95% confidence interval (CI) was calculated. Cancellation of MR-guided biopsy due to lesion nonvisualization occurred in 8% (70 of 907) of patients and in 8% (74 of 911) of lesions. Factors associated with a significantly higher cancellation rate included marked and moderate versus mild and minimal background parenchymal enhancement (38 of 316 [12%] vs 32 of 591 [5%], P = .001), extremely and heterogeneously dense versus scattered fibroglandular densities and fatty parenchymal volume (64 of 712 [9%] vs six of 195 [3%], P = .006), and lesions 1 cm or less in size (52 of 520 [10%] vs 22 of 391 [6%], P = .02).The rate of cancellation per year was highest in the first year, with a decrease in subsequent years (14 of 102 [14%] vs 56 of 805 [7%], P = .025). A significantly lower rate was found in women with synchronous breast cancer (nine of 240 [4%] vs 61 of 667 [9%], P = .007), and a significantly higher rate was found in women with a history of cancer (35 of 315 [11%] vs 35 of 592 [6%], P = .01). Among 58 women who had MR imaging follow-up, no cancers were identified. Among three women who underwent mastectomy after cancellation, one had ductal carcinoma in situ in the same quadrant as the MR-depicted lesion. The cancer detection rate among 61 women who underwent either MR imaging or pathologic follow-up was 2% (one of 61) (95% CI: 0.4%, 9%). MR imaging-guided breast biopsy was canceled due to lesion nonvisualization in 8% of the patients. Although the cancer detection rate among the lesions for which biopsy was canceled is low (95% CI: 0%, 9%), short-term follow-up MR imaging is prudent.

Predicting the severity of relapsing-remitting MS: The contribution of cross-sectional and short-term follow-up MRI data

Background and objective: Predicting the long-term clinical course of multiple sclerosis (MS) is difficult on clinical grounds. Recent studies have suggested magnetic resonance imaging (MRI) metrics to be helpful. We wanted to confirm this. Methods: Contactable individuals (N = 84) from an initial 99 patients with relapsing–remitting MS (RRMS) who had undergone careful baseline and 2-year follow-up examinations including MRI were reassessed after a mean of 10.8 ± 2.7 years. We investigated using multivariate linear regression analyses if clinical and MRI data obtained at the prior time-points and the rates of change in morphologic variables over a mean observational period of 2.5 years could have served to predict a patient’s MS severity score (MSSS) 11 years later. Conversion to secondary progressive MS (SPMS) was a further outcome variable. Results: In univariate analyses, the ‘black hole ratio’ (BHR) at baseline (p = 0.017, beta = 0.148) and at first follow-up (p = 0.007, beta = −0.154) was the only MRI parameter showing a significant correlation with the MSSS. In a multiple regression model, the independent predictive value of imaging variables became statistically non-significant and the latest MSSS was predicted primarily by the baseline EDSS (r 2 = 0.28; p < 0.001). The BHR at baseline explained 9.4% of variance of conversion to SPMS (p = 0.033). Over the observational period the MSSS remained stable in patients remaining RRMS, but increased in converters to SPMS from 4.0 to 6.4. Conclusions: We failed to confirm a clear independent contribution of cross-sectional and short-term follow-up MRI data for the prediction of the long-term clinical course of MS. The MSSS is not a stable indicator of disease severity but may increase in converters to SPMS.

Long-Term Monitoring of Infliximab Therapy for Perianal Fistulizing Crohn's Disease by Using Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) is used to assess the outcome of infliximab (IFX) therapy in patients with perianal fistulizing Crohn's disease (pfCD). However, few long-term data are available about its efficacy. We assessed 59 patients with pfCD by MRI and clinical evaluation at baseline. Treated patients then received paired clinical and MRI examinations for a median time period of 36 (11-53.3) weeks. Short-, mid-, and long-term effects of therapy, as well as the ability of MRI to predict treatment outcome and need for surgery, were evaluated. Compared with the baseline MRI, the short-term follow-up MRI (n = 29) revealed a reduced number of fistula tracks in 13.8% and in the inflammatory activity in 55.2% of patients, respectively; mid-term MRI (n = 25) in 56% and in 52%, respectively; and long-term MRI (n = 13) in 15.4% and in 31%, respectively. Improvement of pfCD based on MRI results coincided with clinical improvement in 54.7% of the patients. Short-term and mid-term (but not long-term) MRI showed a significant decrease in the activity score. Therapy outcome was worse among patients with persisting fistulas (P = .01), collections (P = .009), and rectal wall involvement (P = .01) in the final MRI. Patients with single-branched fistulas (P < .0001) and collections (P = .006) in their baseline MRI were more likely to undergo surgery. MRI is a useful technique for evaluation of pfCD during the first year of follow-up. In the long-term, the MRI improvement coincides with clinical and endoscopic response to IFX in 50% of the patients.

Onyx Embolization of Sporadic Angiomyolipoma

Percutaneous embolization is the currently preferred treatment of symptomatic or ruptured renal angiomyolipomas (AMLs). Alcohol, microparticles, and coils are usually used. We present what is to our knowledge the first case of successful embolization of a solitary sporadic AML with the use of a new nonadhesive liquid embolic agent (ethylene vinyl alcohol copolymer; Onyx). Onyx injection was slow and controllable and achieved complete tumor devascularization, producing a characteristic appearance like a vascular cast. Short-term follow-up magnetic resonance imaging showed complete tumor necrosis without any recurrent pathologic vessels. The specific features, potential advantages in AML treatment, and technical limitations of this new liquid embolic agent are discussed.

Pediatric nonvertebral paraspinal arteriovenous fistulas along the segmental nerve: clinical, imaging, and therapeutic considerations

The authors characterize the clinical presentation and imaging features of paraspinal nonvertebral arteriovenous fistulas (AVFs) along the segmental nerve and describe their endovascular treatment. The authors undertook a retrospective review of medical records, imaging, and treatment of patients with endovascular problems spanning the period from 1985 to 2003. Five pediatric patients (2-3 years of age) received diagnoses of nonvertebral paraspinal AVFs along the segmental nerve. All patients presented with an incidentally discovered continuous murmur over the paraspinal or parasternal regions. All patients were neurologically intact; two patients had cardiomegaly. The AVF was found in the midthoracic level in four patients and at L-3 in one patient. All AVFs were high-flow single-hole fistulas at the neural foramen with venous drainage into paraspinal and epidural veins but without intradural reflux. All fistulas were endovascularly occluded in the same session as diagnostic angiography took place. The fistula was completely occluded, with detachable coils in one case and with N-butyl-cyanoacrylate (NBCA) in four cases. Before NBCA injection, the flow through the fistula was decreased either by placing coils distal to the fistula or by inflating a balloon proximally. No signs of recanalization appeared on short-term follow-up magnetic resonance imaging in all patients. All patients remained neurologically intact at the last available follow-up session (mean 6 years). Nonvertebral paraspinal AVFs along the segmental nerve are specific disease entities seen in children presenting with bruit and cardiomegaly. Endovascular embolization should be the treatment of choice for this rare disease.

Accelerated spondylotic changes adjacent to the fused segment following central cervical corpectomy: magnetic resonance imaging study evidence.

The authors studied whether cervical spine motion segments adjacent to a fused segment exhibit accelerated degenerative changes on short-term follow-up magnetic resonance (MR) imaging. Preoperative and short-term follow-up (mean duration 17.5 months, range 10-48 months) cervical MR images obtained in 44 patients who had undergone one- or two-level corpectomy for cervical spondylotic myelopathy were evaluated qualitatively and quantitatively. The motion segment adjacent to the fused segment and a segment remote from the fused segment were evaluated for indentation of the thecal sac, disc height, and sagittal functional diameter of the spinal canal on midsagittal T2-weighted MR images. Thecal sac indentations were classified as mild, moderate, and severe. New indentations of the thecal sac of varying severity (mild in 17 patients [38.6%], moderate in 10 [22.7%], and severe in six [13.6%]) had developed at the adjacent segments in 33 (75%) of 44 patients. The degenerative changes were seen at the superior level in 11 patients, inferior level in 10 patients, and at both levels in 12 patients and resulted from both anterior and posterior element degeneration in the majority (23 [69.6%]) of patients. The remote segments showed mild thecal sac indentations in seven patients and moderate indentations in two patients (nine [20.5%] of 44). Compared with the changes at the remote segment, the canal size was significantly decreased at the superior adjacent segment by 0.9 mm (p = 0.007). No patient sustained a new neurological deficit due to adjacent-segment changes. On short-term follow-up MR imaging, levels adjacent to the fused segment exhibited more pronounced degenerative changes (compared with remote levels) in 75% of patients who had undergone one- or two-level central corpectomy.