MR Findings Research Articles

Muscular sarcoidosis involving the chest and abdominal walls: case report with MR imaging

Sarcoidosis is an inflammatory disorder that is characterized by the presence of noncaseating granulomas in tissues, involving many organs and tissues. Extra-pulmonary, especially muscular sarcoidosis is a rare condition. The most common location of the muscular sarcoidosis is known to be the proximal muscles of the extremities; however, there have been no cases of diffuse involvement of the chest and abdominal wall muscles. Here, we report a rare muscular sarcoidosis with infiltrative pattern in the chest and abdominal wall muscles and describe the MR imaging findings that were mistaken as lymphoma at initial diagnosis. Although our case did not show characteristic MR findings of muscular sarcoidosis, clinicians or radiologists who are aware of these imaging features can perform early systemic survey for sarcoidosis. Also muscle biopsy is very important to confirm the sarcoidosis and distinguish it from other tumors.

Bone Tumors of the Hands: Focus on CT and MR Findings

Bone Tumors of the Hands: Focus on CT and MR Findings

Fluid distribution in ankle and midfoot joints: MR findings in asymptomatic volunteers.

The purpose of this study is to assess the amount of fluid in the joints of the ankle and midfoot on MR imaging in asymptomatic volunteers. Twenty-one healthy asymptomatic volunteers (42 ankles) were evaluated with MRI imaging. There were 13 men and 8 women. The mean age was 24.7years (19-42years). MR imaging was performed on a 3T MR system using proton density weighted images with fat saturation (TR 2969, TE 30ms, NA 2, slice thickness 2.5mm). Images were obtained in three orthogonal planes. The images were interpreted by two radiologistsin two sessions. The maximum size of the joint effusion was measured in one plane. Descriptive statistics and variation between interpretation sessions were calculated. Fluid in the anterior tibiotalar joint had a mean size of 2.0mm (0.0-5.5mm), in the posterior tibiotalar joint 3.1mm (0.0-6.3mm), in the talonavicular joint 0.7mm (0.0-2.9mm), and in the anterolateral recess 2.0mm (0.0-4.3mm). Fluid in the posterior aspect of the posterior subtalar joint had a mean size of 2.6mm (0.0-9.4mm), in the anterior aspect of the posterior subtalar joint 1.9mm (0.0-6.6mm), at the middle subtalar joint 0.1mm (0.0-1.7mm), and at the anterior subtalar joint 1.6mm (0.0-6.0mm). Fluid in the tibiofibular joint had a mean height of 8.1mm (0.0-16.4mm). In asymptomatic volunteers, moderate to large amounts of fluid were common in all joint recessesof ankle and midfoot, and most pronounced in the anterior and posterior tibiotalar joint, anterolateral recess, and posterior subtalar joint. This should not be mistaken for evidence of a pathological condition.

Enlarged perivascular spaces are associated with the disease activity in systemic lupus erythematosus

To determine whether any brain MR abnormalities, including enlarged perivascular spaces (EPVS), were associated with disease activity in systemic lupus erythematosus (SLE) as an inflammatory activity. One hundred and thirty SLE patients with normal MR findings were assessed. With regard to MRI abnormalities, patients with brain atrophy and mild white matter hyperintensity (WMH) on T2WI were not excluded. The disease activity was assessed using the SLEDAI and the BILAG scores. The imaging characteristics included centrum semiovale EPVS (CS- EPVS) and basal ganglia EPVS on T2WI, WMH, and brain atrophy. We used univariate and multivariate logistic regression analyses to determine the clinical (vascular risk factors and blood examinations) and imaging characteristics that were associated with the disease activity of SLE. High CS-EPVS to be the only factor that was independently associated with the severity of the SLEDAI and BILAG scores (odds ratio [OR] 5.77; 95% confidence interval [CI] 2.21–15.00; p < 0.001 for the SLEDAI, and OR 2.64; 95% CI 1.03–6.74; p = 0.042 for the BILAG score). The CS-EPVS in the SLE patients are associated with the systemic disease activity, suggesting that CS- EPVS may be indicative of the reactive changes of the white matter due to the inflammatory activity.

Mimics of spinal dural arteriovenous fistula and spinal arteriovenous malformation

Background: Spinal dural arteriovenous fistula (SDAVF) and spinal arteriovenous malformation (SAVM) are the most common spinal vascular lesions. Serpentine perimedullary veins and spinal cord edema are the classic pathognomonic MR finding. However, abnormalities such as dilated tortuous veins from non-arteriovenous shunting etiologies can mimic these classic features on MRI.

MR finding of deltoid ligament tear: Which component of the deltoid ligament was injury-prone?

MR finding of deltoid ligament tear: Which component of the deltoid ligament was injury-prone?

EP10.09: Added value of prenatal MR in the evaluation of fetal cleft lip, cleft palate and micrognathia

The aim of this study was to describe MR findings and to determine the accuracy of fetal MRI in diagnosing fetal cleft lip, cleft palate, and micrognathia, either isolated, or in association with additional abnormalities. We reviewed our fetal MRI database from March 2011 through February 2017 and searched for exams referred for cleft lip, cleft palate, and/or micrognathia. A total of 37 fetal exams were identified. 7 cases were lost to follow up, 6 patients underwent termination of pregnancy. Anatomic facial landmarks and biometric parameters were documented including evaluation of the lips, maxillary ridge, position of the tongue, presence/absence of the palate, measurement of the jaw index to evaluate for micrognathia, and binocular and intraocular diameter to evaluate for hypo/hypertelorism. A complete fetal neuroevaluation was performed to detect additional anomalies. Findings on fetal MR were correlated post delivery. In the remaining cohort of 21 fetuses, 20 cases were diagnosed with positive findings. There were 6 diagnoses of cleft lip, 7 diagnoses of cleft lip and palate, 4 isolated micrognathia, 5 micrognathia with isolated cleft palate consistent with Pierre Robin sequence. Of the 21 fetuses, the MR diagnosis was confirmed following delivery in 17 cases. Syndromes that were seen with micrognathia included Dandy Walker, Frynn's, Emanuel, and mid-face hypoplasia syndromes. There was 1 false positive case of cleft lip and palate due to a tethered frenulum. Three cases are waiting to deliver. MRI has a 95.5% degree of accuracy in diagnosing fetal facial abnormalities, including isolated cleft lip, cleft lip with cleft palate, micrognathia with cleft palate (Pierre Robin syndrome), and isolated syndromic micrognathia with additional non-palatal abnormalities.

Characteristic MR findings suggesting presumed labyrinthine hemorrhage

Objectives: To evaluate the magnetic resonance imaging (MRI) findings of labyrinthine hemorrhage as a cause of sudden sensorineural hearing loss (SSNHL).Methods: MRI scans of 59 patients with SSNHL were retrospectively analyzed and compared to clinical features and audiometry data. MR images included pre-enhanced T1-weighted, 3D FLAIR volume isometric turbo spin-echo acquisition (VISTA), post-enhanced T1-weighted and 4-h-delayed enhanced FLAIR VISTA, and 3D thin-section proton density-weighted images.Results: High labyrinth signals were seen on pre-enhanced T1-weighted and 3D FLAIR VISTA images with no enhancement for 6 of 59 (10.2%) patients with SSNHL. In these six patients with presumed inner-ear hemorrhage, high signal intensity was seen in the endolymphatic and perilymphatic portions of the labyrinth on T1-weighted and 3D FLAIR VISTA images. In patients with SSNHL with nonhemorrhagic causes such as vestibular schwannoma or labyrinthitis, high signal or labyrinthine enhancement was seen only in the perilymphatic portion of the labyrinth on pre- or post-enhanced 3D FLAIR VISTA images.Conclusions: MRI using pre-enhanced T1-weighted, 3D FLAIR VISTA, and post-enhanced T1-weighted, 4-h delayed enhanced FLAIR VISTA images is able to identify labyrinthine hemorrhage as the cause of SSNHL. High signals in both the endolymphatic and perilymphatic portions of the labyrinth on pre- or post-enhanced 3D FLAIR VISTA images without enhancement indicate labyrinthine hemorrhage.

MR imaging findings of vertebral involvement in Gorham-Stout disease, generalized lymphatic anomaly, and kaposiform lymphangiomatosis.

To assess the MR imaging findings of vertebral involvement in Gorham-Stout disease (GSD), generalized lymphatic anomaly (GLA), and kaposiform lymphangiomatosis (KLA). Nine patients (three patients with GSD, three with GLA, and three with KLA) who underwent whole-spine MR examinations were included. MR findings of fatty marrow replacement and prolonged T1 and T2 lesions of the vertebrae were retrospectively assessed. Prolonged T1 and T2 lesions were defined as well-defined and round-, oval-, or geographic-shaped areas. Six patients [one (33%) patient with GSD, two (67%) with GLA, and three (100%) with KLA] showed both fatty marrow replacement and prolonged T1 and T2 lesions. Fatty marrow replacement was seen in the cervical spine of two (33%) patients, thoracic spine of six (100%), lumbar spine of six (100%), and sacral spine of two (33%). Prolonged T1 and T2 lesions were seen in the cervical spine of three (50%) patients, thoracic spine of three (50%), lumbar spine of six (100%), and sacral spine of three (50%). Both fatty marrow replacement and prolonged T1 and T2 lesions of the vertebrae could be observed in GSD, GLA, and KLA. The most commonly affected site was the lumbar spine, followed by the thoracic spine.

MR Imaging of the Achilles Tendon after Surgical Repair.

Achilles tendon tear is common and increasingly frequent. Magnetic resonance imaging (MRI) is the modality of choice for radiological evaluation. It is accurate to assess the status and integrity of the tendon with well documented features. In this article, the MR findings of a normal Achilles tendon as well as common diseases like insertional and noninsertional tendinosis, chronic tendinosis with marked lengthening, tendon rupture are illustrated. After a torn Achilles tendon receives surgical repair, it undergoes different stages of healing process including inflammatory, reparative and remodeling phases. Acute scar tissue in the surgical bed may share similar MR features of tendon re-rupture especially in the early healing phase because both are T2W hyperintense. The size of the gap may even appear larger than expected on T2W images possibly due to tendon remodeling. Understanding of the healing process in post-operative period may prevent overestimation of tendon gap and misdiagnosis of re-tear. We describe the MR features of the post-operative changes with serial studies in different months after surgery. The MR findings with the highlights of the expected sequential changes in normal healing process are illustrated in different cases. A case with surgical repair on a partial tear of Achilles tendon is also included.

“Isolated long thoracic nerve palsy”: More than meets the eye

Two main hypotheses have been proposed for the pathophysiology of long thoracic nerve (LTN) palsy: nerve compression and nerve inflammation. We hypothesized that critical reinterpretation of electrodiagnostic (EDX) studies and MRIs of patients with a diagnosis of non-traumatic isolated LTN palsy could provide insight into the pathophysiology and, potentially, the treatment. A retrospective review was performed of all patients with a diagnosis of non-traumatic isolated LTN palsy and an EDX and brachial plexus or shoulder MRI studies performed at our institution. The original EDX studies and MR examinations were reinterpreted by a neuromuscular neurologist and musculoskeletal radiologist, respectively, both blinded to our hypothesis. Seven patients met the inclusion criteria as having a non-traumatic isolated LTN palsy. Upon reinterpretation, all of them were found to have findings not consistent with an isolated LTN. On physical examination, three of them (43%) presented with weakness in muscles not innervated by the LTN. Four of them (57%) had additional EDX abnormalities beyond the distribution of the LTN. Five of them (71%) had MRI evidence of enlargement of nerves or denervation atrophy of muscles outside the innervation of the LNT, without evidence of compression of the LTN in the middle scalene muscle. In our series, all 7 patients, originally diagnosed as having an isolated LTN, on reinterpretation, were found to have a more diffuse muscle/nerve involvement pattern, without MR findings to suggest nerve compression. These data strongly support an inflammatory pathophysiology.

Pre-clinical evaluation of a nanoparticle-based blood-pool contrast agent for MR imaging of the placenta

IntroductionNon-invasive 3D imaging that enables clear visualization of placental margins is of interest in the accurate diagnosis of placental pathologies. This study investigated if contrast-enhanced MRI performed using a liposomal gadolinium blood-pool contrast agent (liposomal-Gd) enables clear visualization of the placental margins and the placental-myometrial interface (retroplacental space). Non-contrast MRI and contrast-enhanced MRI using a clinically approved conventional contrast agent were used as comparators. Materials and methodsStudies were performed in pregnant rats under an approved protocol. MRI was performed at 1T using a permanent magnet small animal scanner. Pre-contrast and post-liposomal-Gd contrast images were acquired using T1-weighted and T2-weighted sequences. Dynamic Contrast enhanced MRI (DCE-MRI) was performed using gadoterate meglumine (Gd-DOTA, Dotarem®). Visualization of the retroplacental clear space, a marker of normal placentation, was judged by a trained radiologist. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated for both single and averaged acquisitions. Images were reviewed by a radiologist and scored for the visualization of placental features. Contrast-enhanced CT (CE-CT) imaging using a liposomal CT agent was performed for confirmation of the MR findings. Transplacental transport of liposomal-Gd was evaluated by post-mortem elemental analysis of tissues. Ex-vivo studies in perfused human placentae from normal, GDM, and IUGR pregnancies evaluated the transport of liposomal agent across the human placental barrier. ResultsPost-contrast T1w images acquired with liposomal-Gd demonstrated significantly higher SNR (p = 0.0002) in the placenta compared to pre-contrast images (28.0 ± 4.7 vs. 6.9 ± 1.8). No significant differences (p = 0.39) were noted between SNR in pre-contrast and post-contrast liposomal-Gd images of the amniotic fluid, indicating absence of transplacental passage of the agent. The placental margins were significantly (p < 0.001) better visualized on post-contrast liposomal-Gd images. DCE-MRI with the conventional Gd agent demonstrated retrograde opacification of the placenta from fetal edge to the myometrium, consistent with the anatomy of the rat placenta. However, no consistent and reproducible visualization of the retroplacental space was demonstrated on the conventional Gd-enhanced images. The retroplacental space was only visualized on post-contrast T1w images acquired using the liposomal agent (SNR = 15.5 ± 3.4) as a sharply defined, hypo-enhanced interface. The retroplacental space was also visible as a similar hypo-enhancing interface on CE-CT images acquired using a liposomal CT contrast agent. Tissue analysis demonstrated undetectably low transplacental permeation of liposomal-Gd, and was confirmed by lack of permeation through a perfused human placental model. ConclusionsContrast-enhanced T1w-MRI performed using liposomal-Gd enabled clear visualization of placental margins and delineation of the retroplacental space from the rest of the placenta; the space is undetectable on non-contrast imaging and on post-contrast T1w images acquired using a conventional, clinically approved Gd chelate contrast agent.

Van Der Knaap disease; A case having a defined mutation and novel mutation

Context: Van der Knaap Syndrome (MLC1) is a slowly progressive neurodegenerative diseasecharacterized by macrocephaly, megalencephaly, ataxia, spasticity, motor retardation, moderatemental retardation, diffuse cerebral white matter, subcortical cysts (MEGALENCEPHALICLEUKOENCEPHALOPATHY WITH SUBCORTICAL CYSTS 1,OMIM 604004). The prevalence is reportedapproximately 1/1,000,000. MLC1 is a autosomal recessive disorder due to mutations in the MLC1gene at 22q13.33 locus localization. In this study, aimed to diagnose a girl who is guided by ataxicwalking and pathologic cranial MR findings of a family with first degree cousin marriage and to givegenetic counseling to the family. Methods: Affected girls and their parents were included in the study. The cranial MR and examination findings of the index case were evaluated and MLC1 gene have been analyzed by a next generation sequencing methods. Results: Parent 7 years old , ataxic walking, spasticity, slowing of motor movements and intrinsic tremor, cranial MR showed a pathologic signal increase in cerebral white matter compatible with neurometabolic disease. Macrocephaly in infantile period. The amino acid and acylcarnitine profiles were evaluated as normal with the tandem mass spectrometry. MLC1 gene sequence analysis including all coding exons and exon-intron boundiries was done and MLC1 gene NM_015166.3: IVS2+1G>T (c.177+1G>T) homozygous mutation was detected. This mutation was previously described and have been reported (HGMD No: CS035660). In the familial segregation this mutation was detected heterozygous in parents. In addition, previously undeA (c.1059+6T>A) heterozygous mutation was detected in the parent. In silico analysis with Mutation Taster, Polyphen2, SIFT was predict this variant as a disease causing mutation. Prenatal, preimplantation genetic diagnosis for new pregnancies was recommended especially for those who are married to relatives. Since MLC1 is a rare form of megaencephalic leukoencephalopathy, it is presented to emphasize that parents with macrocephaly, ataxic gait and diffuse white matter involvement should be kept in mind.

Breast MR imaging for the assessment of residual disease following initial surgery for breast cancer with positive margins.

To determine the accuracy of post-operative MR in predicting residual disease in women with positive margins, emphasizing the size thresholds at which residual disease can be confidently identified. This IRB-approved HIPAA-compliant retrospective study included 175 patients with MR after positive margins following initial surgery for breast cancer. Two expert readers independently re-evaluated MR images for evidence of residual disease at the surgical cavity and multifocal/multicentric disease. All patients underwent definitive surgery and MR findings were correlated to histopathology. 139/175 (79.4%) patients had residual disease at surgery. Average overall sensitivity, specificity, PPV and NPV for residual disease at the surgical cavity were 73%, 72%, 91% and 45%, respectively. The readers identified 42/45 (93%, reader 1) and 43/45 (95%, reader 2) patients with residual invasive disease at the cavity of ≥5mm and 22/22 (100%, both readers) patients with disease ≥10mm. Average sensitivity, specificity, PPV and NPV for unknown multifocal/multicentric disease were 90%, 96%, 93% and 86%, respectively. Post-operative breast MR can accurately depict ≥5-mm residual disease at the surgical cavity and unsuspected multifocal/multicentric disease. These findings have the potential to lead to more appropriate selection of second surgical procedures in women with positive margins. • Post-operative breast MRI accurately defines residual disease of ≥5mm. • Surgical cavity sensitivities were high for both invasive carcinoma and DCIS. • Post-surgical changes and very small residual disease (<5mm) may overlap. • Post-operative breast MRI may help planning an accurate re-resection.

Study of susceptibility weighted imaging on MR and pathologic findings to distinguish benign or malignant soft tissue tumor

Objective: To explore the diagnostic performance of susceptibility weighted imaging (SWI)in distinguishing benign or malignant soft tissue tumor, and to study pathological observation. Methods: Sixty-eight patients with soft tissue tumor, who received no previous treatment or invasive examination, received routine preoperative MRI examination and SWI scanning. The graduation and distribution of intratumoral susceptibility signal intensity(ITSS) and proportion of tumor volume were observed.The pathological results were also included for comparative analysis. Results: Fourty of 68 patients were benign and 28 were malignant. 72.5% (29/40) patients with benign soft tissue tumors were ITSS grade 1 and ITSS grade 3 (hemangioma). 89.3%(25/28) patients with malignant soft tissue tumors were ITSS grade 2 and ITSS grade 3. The difference was statistically significant (P<0.01). The distribution of ITSS in patients with benign soft tissue tumors was dominated by peripheral distribution and diffuse distribution (hemangioma), accounting for 90.0% (36/40). The distribution of ITSS in patients with malignant soft tissue tumors mainly distributed in the central region, accounting for 78.6% (22 /28). The difference was statistically significant (P<0.01). The proportion of tumor volume occupied by ITSS in benign soft tissue tumors was <1/3 and> 2/3 (hemangioma), accounting for 90.0% (36/40). The volume of malignant soft tissue tumors were predominantly <1/3 , accounting for 82.1% (23/28). The difference was statistically significant (P<0.01). Conclusion: SWI is sensitive in displaying the vein and blood metabolites in soft tissue lesions, which is helpful for the differential diagnosis of benign and malignant tumors in soft tissue.

Analysis of correlation factors of MR diffusion-weighted imaging in patients with acute cerebral infarction

Objective To explore the correlation factors of cranial magnetic resonance diffusion weighted imaging(DWI) in patients with acute cerebral infarction. Methods A total of 350 patients with acute cerebral infarction who underwent MR imaging were divided into DWI positive group and negative group according to whether the first diffusion weighted imaging was abnormal or not.The clinical and radiological data of the two groups were retrospectively collected and analyzed.patients with negative DWI on initial MRI were re-examined 1 week later. Result Thirty-four(9.7%) patients were DWI-negative in 350 patients with acute cerebral infarction on initial MRI, and 5 patients in DWI-negative group had positive lesions on the re-examine MRI.Multivariate logistic regression analysis indicated the patients with first blood pressure of admission≥ 140/90 mmHg(P=0.033), first blood glucose of admission≥ 7.0 mmol/L(P=0.028) and the time from the onset to initial MRI>24 h were more likely showed DWI-positive on initial MRI(P=0.013). Patients with posterior circulation infarcts were more likely to have negative DWI findings than patients with anterior circulation infarction(P=0.001). Conclusion Some patients with acute cerebral infarction may show DWI negative results on initial MRI, which is related with the time from onset to initial MRI and the site of cerebral infarction.Patients with posterior circulation infarcts are more likely to have first negative MR findings than patients with anterior circulation infarction.Patients with elevation of the admission blood pressure or blood glucose are more likely to have DWI positive lesions.Patients with acute cerebral infarction within the time window should received be thrombolytic therapy after carefully assessment to avoid delay in treatment even if the DWI negative results. Key words: Acute cerebral infarction; Magnetic resonance negative; Influencing factors

Pathological findings of uterine tumors preoperatively diagnosed as red degeneration of leiomyoma by MRI

PurposeVenous infarction of a leiomyoma is known as red degeneration of leiomyoma (RDL) and can be a cause of acute abdomen. Although magnetic resonance imaging (MRI) is the only modality that can depict the inner condition of a leiomyoma, the typical MR findings of RDL are sometimes identified incidentally even in asymptomatic patients. The purpose of this study is to clarify common pathological findings of uterine tumors preoperatively diagnosed as RDL by MRI.MethodsWe diagnosed 28 cases of RDL by MRI from March 2007 to April 2015. The ten lesions subjected to pathological analysis after resection were included in the study and reviewed by a gynecological pathologist. The average time from MRI to operation was 4.7 months.ResultsThe typical beefy-red color was not observed on the cut surface of the tumor except in one tumor resected during the acute phase. All lesions diagnosed as RDL by MRI had common pathological findings consistent with red degeneration of leiomyoma, including coagulative necrosis. Other common pathological features of RDL besides extensive coagulative necrosis appear to be a lack of inflammatory cell infiltrate or hemorrhage in the entire lesion.ConclusionsAlthough RDL is known to cause acute abdomen, its typical MR findings can be observed even in asymptomatic patients in a condition that manifests long after red degeneration. The characteristic pathological findings in both the acute phase and the chronic phase that we found in this study, along with radiology reports, will be helpful references for gynecologists and pathologists in suspecting a history of red degeneration and confirming the diagnosis.

Advances in MRI around metal.

4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:972-991.

Adnexal masses associated with peritoneal involvement: diagnosis with CT and MRI.

Given the unique intra-peritoneal anatomic location of the adnexa, tubo-ovarian diseases can commonly spread into the peritoneal cavity. Peritoneal seeding may occur in a spectrum of adnexal conditions including infectious diseases, endometriosis, and benign or malignant primary or secondary ovarian tumors. CT is usually the imaging modality on which the concomitant involvement of the peritoneum and the ovary is depicted. The first diagnosis to be considered by the radiologist is generally peritoneal carcinomatosis from ovarian cancer but other conditions cited above have also to be borne in mind and may be suggested on the basis of careful assessment of CT findings or on further MR findings. MRI may indeed help characterize the lesions in some cases. The purpose of this review is to describe the clinical and imaging patterns of peritoneal involvement that may be found in association with different ovarian lesions. Familiarity with these patterns and diagnoses will help the radiologist narrow the differential diagnosis and make an accurate diagnosis, thus facilitating patient management and avoiding unnecessary invasive treatment.

Imaging feature in PRES syndrome: Report of 6 cases

Objectives Posterior reversible encephalopathy syndrome (PRES) is a rare syndrome. The pathophysiology is poorly understood. Computed tomography (CT) and magnetic resonance imaging (MRI) findings are characteristic of the diagnosis and diffusion weighted image has been also suggested having a prognostic value. We report this unusual neurologic complication of peripartumin except any pre-existent pathology of the pregnancy. Materiel and methods CT, MR findings and relevant clinical data of the patients were retrospectively reviewed on 5 cases between 2011 and 2012 in our radiologic department. Results Eclampsia was responsible in all cases. CT finding were bilaterally symmetric low density in the posterior parietal and occipital lobes consistent with vasogenic edema on FLAIR and diffusion MR images ( Fig. 1 , Fig. 2 ). Conclusion Since PRES is often unsuspected by clinicians, radiologists may be the first to suggest the diagnosis. As this diagnosis has important therapeutic and prognostic implications, radiologists should be aware of the spectrum of imaging findings in PRES. It consists on an increasingly recognized neurologic disorder with characteristic CT and MR findings.