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Background and Purpose: A high-intensity zone identified on preprocedural MR imaging is known to correlate with pain at provocation lumbar discography. The correlation between enhancing annular fissures and pain at provocation lumbar discography has not been comprehensively evaluated. The purpose of this study was to assess the pain response and imaging features at enhancing annular fissure nonoperated disc levels identified on preprocedural MR imaging with comparison with the high-intensity zone and nonenhancing disc levels in patients referred for provocation lumbar discography., Materials and Methods: One-hundred nonoperated discs in 44 patients were retrospectively evaluated for an enhancing annular fissure on sagittal postcontrast T1-weighted pre-discogram MR imaging. Enhancing annular fissure discs were graded on the sagittal T2-weighted sequence (Grade 4: like CSF to Grade 1: negative/barely visible) for high-intensity-zone conspicuity. High-intensity-zone detection was performed independently. In the primary assessment, enhancing annular fissure and high-intensity zones were associated with pain response at provocation lumbar discography. Additional analysis included intradiscal anesthetic response and postdiscogram CT appearance., Results: Thirty-nine discs demonstrated an enhancing annular fissure, with 23/39 demonstrating a high-intensity zone. The presence of a high-intensity zone predicted severe pain (concordant + nonconcordant; P = .005, sensitivity of 40%, specificity of 94%) and concordant pain ( P = .007, sensitivity of 39%, specificity of 86%) at provocation lumbar discography. Enhancing annular fissures without a detected high-intensity zone were more frequently observed among severely painful (50%) and concordant (36%) discs than among discs negative for pain (9%; P = .01). This finding resulted in a substantially greater overall sensitivity of enhancing annular fissures for severe ( P  < .001, 64%) and concordant pain ( P = .008, 61%), significantly improving the overall predictive ability of a high-intensity zone alone. A high-intensity zone went undetected in 9/11 Grade 1 disc levels with concordant pain present in 7/9., Conclusions: Consideration of enhancing annular fissures on preprocedural MR imaging substantially improves the prediction of severe/concordant pain in provocation lumbar discography., (© 2023 by American Journal of Neuroradiology.)

Objective: While provocation lumbar discography has been used to identify discs responsible for low back pain, the biomechanical effects of disc injection have received little attention. The purpose of this study was to assess the motion of the functional spinal unit including the endplate and facet/pedicle region during disc injection including comparison between normal and degenerative discs., Subjects: Subjects represent 91 consecutive patients referred for discography with chronic low back pain., Methods: Lateral projection vertebral motion was retrospectively analyzed at 232 levels (normal: 76 [32.8%], degenerative: 156 [67.2%]). Pre- and postinjection fluoroscopic images were size scaled, and lower endplates were superimposed on separate PowerPoint images. Upper endplate and facet/pedicle motion was separately and independently analyzed on toggled PowerPoint images, subjectively graded as prominent, intermediate, questionable/uncertain, or no motion. Disc morphology was graded using the anteroposterior/lateral postinjection disc appearance (Adams criteria)., Results: Prominent or intermediate endplate and facet/pedicle motion was identified at most lumbar levels with substantial overall agreement (degenerative: κ = 0.93, 95% confidence intervals [CI] = 0.87-1.00; normal: κ = 0.80, 95% CI = 0.61-1.00). Degenerative levels were strongly associated with a lower degree of endplate and facet/pedicle motion compared with normal: ("prominent" motion grade: endplate: 61% [95/156] vs 89% [68/76], P < 0.001; facet/pedicle: 60% [93/156] vs 88% [67/76], P < 0.001)., Conclusion: Disc injection expands the disc space inducing endplate motion, pedicle motion, and facet translation in almost all normal and most degenerate levels. Disc injection therefore biomechanically "provokes" the entire functional spinal unit. When provoked pain is encountered during lumbar discography, contribution from the associated facet joint and myotendinous insertions should be considered., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background Context: The North American Spine Society's (NASS) Evidence Based Clinical Guideline for the Diagnosis and Treatment of Low Back Pain features evidence-based recommendations for diagnosing and treating adult patients with nonspecific low back pain. The guideline is intended to reflect contemporary treatment concepts for nonspecific low back pain as reflected in the highest quality clinical literature available on this subject as of February 2016., Purpose: The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with nonspecific low back pain. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition., Study Design: This is a guideline summary review., Methods: This guideline is the product of the Low Back Pain Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guideline was submitted to an internal and external peer review process and ultimately approved by the NASS Board of Directors., Results: Eighty-two clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature., Conclusions: The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with nonspecific low back pain. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx., (Copyright © 2020. Published by Elsevier Inc.)

Cervical transforaminal epidural injections (C-TfEI) are commonly performed in patients with cervical radiculopathy/pain. C-TfEIs are typically performed without incident but adverse events can occur. Using CT-fluoroscopy-guided C-TfEI, we commonly observe the vertebral artery in proximity to the target injection site. The purpose of this study was to assess the position of the vertebral artery relative to the typical C-TfEI injection point. CT-fluoroscopy-guided C-TfEIs were performed at 70 levels in 68 patients with radiculopathy/neck pain (age range 19-83 yrs, mean 50.6 yrs). Degenerative neural foraminal narrowing at each level was characterized (normal-to-mild, moderate, severe). Vertebral artery position was categorized as: anterior (normal), partially covering neural foramen, complete/near-complete covering the neural foramen. Additional measured variables included angle of needle trajectory, foraminal angle, and whether or not needle trajectory intersected with the vertebral artery. Foraminal vertebral artery covering correlated with severity of foraminal degenerative narrowing (p=0.003). Complete/near-complete covering was seen in: 65% severely narrowed foramina, 30% moderately narrowed foramina and 10% normal/mildly-narrowed foramina. Needle trajectory intersected with the vertebral artery in 30 of 70 injections (46%) by CT-fluoroscopy, frequently associated with shallow (lateral) approaches. Foraminal angle, approximating oblique fluoroscopic technique, suggests needle trajectory intersection with the vertebral artery in 27 of 70 foramina (39%). Vertebral artery position is commonly displaced into the foramen in patients with advanced cervical degenerative disease. Operator awareness of altered vertebral artery position is important for determination of optimal needle trajectory and tip placement prior to injection in patients undergoing C-TfEI.

Chronic low back pain (LBP) can be 'progressive onset' or injury-related. This study compares the patient-reported cause of chronic LBP to features of disc internal derangement at painful concordant discs evaluated by provocation lumbar discography. Concordant LBP was identified in 114 patients with chronic LBP studied by provocation discography. LBP cause, discogram pain response and discogram/post-discogram CT features of internal derangement were retrospectively reviewed. 'Progressive-onset' LBP was reported in 32 (28%) patients, injury-related LBP in 75 (66%) with LBP equated to non-specific causes in seven. Injury-related LBP was more commonly identified in men (52 of 63 [83%]) with women reporting near-equal frequency of 'progressive-onset' (23 of 44 [52%]) and injury-related (21 of 44 [48%]) LBP (p=0.002). In 172 concordant painful discs, near-equal frequency of severely degenerative (Dallas grade-3: 82 of 172 [47.3%]) and full-thickness radial fissure discs (Dallas grade-3: 90 of 172 [52.7%]) were identified. Women with 'progressive-onset' LBP demonstrated more frequent severely degenerative discs (24 of 37 [65%]); women with injury-related LBP demonstrated more frequent radial-defect discs (21 of 31 [68%]; p=0.01). In men with injury-related LBP, severe degeneration-only (44 of 89 [49%]) and radial defect discs (45 of 89 [51%] were seen with equal frequency. In men with 'progressive-onset' LBP, radial defects are more common (11 of 15 [73%]). 'Progressive-onset' and injury-related chronic LBP subgroups are definable. Gender-related differences in incidence and internal derangement features at concordant discs are identified at discogram/post-discogram CT. These differences may have implications related to LBP origin/treatment-response.

Background and Purpose: Interlaminar LESIs are commonly used to treat LBP or radiculopathy. Most studies focus on the long-term outcomes of LESI. The purpose of this study is to evaluate the immediate effects of fluoroscopically guided LESI on LBP/radiculopathy including low- or high-strength anesthetic response., Materials and Methods: The procedure notes, post-procedure records, and imaging records dedicated spine nurse assessments, and imaging records were retrospectively evaluated in 392 fluoroscopically guided LESIs performed in 276 patients (nonrandomized, nonblinded; 131 males, 145 females; average age, 56 years) with LBP/radiculopathy using either low- or high-strength anesthetic (80 mg of methylprednisilone mixed with bupivacaine [0.25% or 0.5%]). Post-procedure documentation of the patient's pre- and postprocedure VAS pain-scale level were tabulated., Results: Single LESI was performed in 199 patients, with multiple LESIs in 77 (193 injections). Low-strength bupivacaine (0.25%) was used in 237 injections, with high-strength (0.5%) in 155. Complete to near-complete immediate pain relief (<20% residual pain) was reported after 197 of 392 (50.3%) injections. No pain relief was reported after 60 (15.4%) injections (>80% residual), with partial relief in the remainder. No statistical difference was noted between low- and high-anesthetic strength or between single- and multiple-injection patients. In multiple-LESI patients, consistent pain relief response was noted in 39 of 77 (50.6%) patients, with improving LESI response in 20.8%, deteriorating LESI response in 19.5%, and variable response in 9.1%., Conclusions: An immediate pain-extinction response is identified after LESI, which appears independent of anesthetic strength. This observation may relate to pain origin and/or pain nociceptor afferent pathway in an individual patient and potentially relate to treatment response.

Posterior reversible encephalopathy syndrome (PRES) is an uncommon but well-known complication after transplantation diagnosed by characteristic radiological features. As limited data on this complex syndrome exist we sought to better define the incidence, clinical presentation and risk factors for PRES in liver transplant (LTx) patients. We conducted a retrospective analysis of 1923 adult LTx recipients transplanted between 2000 and 2010. PRES was diagnosed radiologically in 19 patients (1%), with 84% of cases occurring within 3 months post-LTX. We compared this cohort of PRES patients to 316 other LTx recipients also requiring radiographic imaging within 3 months after LTx for neurological symptoms. Seizure was the most common clinical manifestation in the PRES group (88% vs. 16%, p< 0.001) and 31% had an intracranial hemorrhage. Those with hemorrhage on imaging were more likely to be coagulopathic. PRES patients were significantly more likely to have had alcoholic liver disease and infection/sepsis. These factors may be related to a common pathway of vascular dysregulation/damage that appears to characterize this complex syndrome. Intracranial bleeding and seizures may be the end result of these phenomena. The relationship of these associated factors to the hypothesized pathophysiology of PRES is discussed., (© Copyright 2012 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Annular margin shape is used to characterize lumbar disc abnormality on CT/MR imaging studies. Abnormal discs also have internal derangement including annular degeneration and radial defects. The purpose of this study was to evaluate potential correlation between disc-margin shape and annular internal derangement on post-discogram CT in significantly painful discs encountered at provocation lumbar discography (PLD). Significantly painful discs were encountered at 126 levels in 86 patients (47 male, 39 female) studied by PLD where no prior surgery had been performed and response to intradiscal lidocaine after provocation resulted in either substantial/total relief or no improvement after lidocaine administration. Post-discogram CT and discogram imaging was evaluated for disc-margin characteristics (bulge/protrusion), features of disc internal derangement (radial annular defect [RD: radial tear/fissure/annular gap], annular degeneration) and presence/absence of discographic contrast leakage. In discs with focal protrusion, 50 of 63 (79%) demonstrated Grade 3 RD with 13 (21%) demonstrating severe degenerative change only. In discs with generalized-bulge-only, 48 of 63 (76%) demonstrated degenerative change only (primarily Dallas Grade 3) with 15 of 63 (24%) demonstrating a RD (Dallas Grade 3). Differences were highly statistically significant (p<0.001). Pain elimination with intra-discal lidocaine correlated with discographic contrast leakage (p<0.001). Disc-margin shape correlates with features of internal derangement in significantly painful discs encountered at PLD. Discs with focal protrusion typically demonstrate RD while generalized bulging discs typically demonstrated degenerative changes only (p<0.001). Disc-margin shape may provide an important imaging clue to the cause of chronic discogenic low back pain.

The case of a 75-year-old man with a history of lymphoma, recent upper respiratory tract infection, and a protracted course of encephalopathy is presented. Radiologically, findings were consistent with posterior reversible encephalopathy syndrome. A brain biopsy revealed evidence of endothelial activation, T-cell trafficking, and vascular endothelial growth factor expression, suggesting that systemic immune system activation may be involved with triggering posterior reversible encephalopathy syndrome. In addition, underlying cerebral amyloid angiopathy may have contributed to the initial nonclassical edema distribution by compromising autoregulatory blood flow mechanisms.

Recurrent or persistent low back pain (LBP) after lumbar fusion can be related to many factors. We reviewed the provocation lumbar diskogram (PLD) features and redo-fusion outcome in our patients evaluated for recurrent/persistent LBP after technically successful fusion. LD was performed in 27 patients with recurrent/persistent LBP after prior successful lumbar surgical fusion (31 fused levels: single-level fusion-23; two-level fusion-4). PLD response and imaging characteristics at fused and non-fused levels were assessed including: intra-diskal lidocaine response, diskogram-image/post-diskogram CT appearance, presence/absence of diskographic contrast leakage, and evidence of fusion integrity or hardware failure. Outcomes in patients having redo-fusion were assessed. Concordant pain was encountered at 15 out of 23 (65%) single-level fusions, non-concordant pain in one fusion with non-painful response in seven. Adjacent-level concordant pain was identified in seven out of 23 (30%) patients (three of 15 with painful fused levels; four of seven with non-painful fusions). In two-level fusions, concordant pain was encountered at one fused level in each patient. In painful fused levels, leaking and contained disks were encountered with partial or complete pain elimination after intra-diskal lidocaine injection. In anterior fusions, space or contrast surrounding the cage was noted at five of 11 levels. Pseudoarthrosis was noted only with trans-sacral screw fusions. Redo-fusion in 13 patients resulted in significant improvement in nine and moderate improvement in one. Patients with recurrent/persistent LBP after technically successful fusion may have a diskogenic pain source at the surgically fused or adjacent level confirmed by lidocaine-assisted PLD.

Encephalopathy is an uncommon complication of childhood influenza infection, typically recognized during influenza epidemics. Imaging hallmarks include characteristic thalamic lesions, thalamic necrosis and hemispheric edema. We describe a child with acute influenza A associated necrotizing encephalopathy with MR angiographic evidence of significant cerebral vasculopathy and a hemispheric edema pattern consistent with PRES. This case reinforces that significant cerebral vasculopathy can accompany influenza infection and that influenza is a likely trigger for PRES.

Background and Purpose: MR imaging of the brain has significant potential in the early detection of neurodegenerative disorders such as AD. The purpose of this work was to determine if perfusion MR imaging can be used to separate AD from normal cognition in individual subjects. We investigated the diagnostic utility of perfusion MR imaging for early detection of AD compared with structural imaging., Materials and Methods: Data were analyzed from 32 participants in the institutional review board-approved CHS-CS: 19 cognitively healthy individuals and 13 with clinically adjudicated AD. All subjects underwent structural T1-weighted SGPR and CASL MR imaging. Four readers with varying experience separately rated each CASL and SPGR scan finding as normal or abnormal on the basis of standardized qualitative diagnostic criteria for observed perfusion abnormalities on CASL or volume loss on SPGR and rated the confidence in their evaluation., Results: Inter-rater reliability was superior in CASL (kappa = 0.7 in experienced readers) compared with SPGR (kappa = 0.17). CASL MR imaging had the highest sensitivity (85%) and accuracy (70%). Frontal lobe CASL findings increased sensitivity to 88% and accuracy to 79%. Fifty-seven percent of false-positive readings with CASL were in controls with cognitive decline or instability within 5 years. Three of the 4 readers revealed a statistically significant relationship between confidence and correct classification when using CASL., Conclusions: Readers were able to separate individuals with mild AD from those with normal cognition with high sensitivity by using CASL but not volumetric MR imaging. This initial experience suggests that CASL MR imaging may be a useful technique for detecting AD.

Background and Purpose: Image-guided selective nerve root block/steroid injection is commonly performed for lumbar radiculopathy. The purpose of this study was to evaluate the clinical/imaging characteristics and injection response of adjacent double-root contributions to unilateral lumbar radiculopathy in a typical interventional spine practice., Materials and Methods: In 132 of 350 patients (37.7%) with unilateral radiculopathy, adjacent double-nerve root block/steroid injection was performed on the basis of preprocedural clinical/imaging characteristics. Clinical presentation (pain pattern, VAS), response to injection, and imaging features of potential root compression/irritation (disk protrusion, subarticular/foraminal stenosis) were tabulated., Results: Clinically, a subset of patients with both L4+L5 and L5+S1 radiculopathy presented with proximal sciatica only in addition to those with typical L4, L5 or S1 radicular patterns. Preprocedural imaging demonstrated evidence of adjacent double-root abnormality in 56 of 79 (71%) patients without prior surgery (single-level disease, 32; 2-level disease, 24) and in all 53 patients with prior lumbar surgery (scar, 42; separate-level root abnormality, 13). Adjacent double-level replication of the patient's familiar pain was present in 82 of 132 (62%) patients, with single-root replication in 37 (28%) and no response in 13 (10%). Typical sciatica was encountered by injection at L4 (15%-33%), likely reflecting furcal nerve lumbar plexus contribution from L5. Sensations from each injected root usually replicated separate recognizable portions of the patient's radiculopathy, with marked or complete pain improvement reported in most patients., Conclusions: Adjacent double-level contributions to lumbar radiculopathy are common, and clinical/imaging clues should be assessed to ensure optimum nerve root block/steroid injection treatment response.

Background and Purpose: Influenza A infection can precipitate encephalopathy, encephalitis, or Reye syndrome with the development of cerebral edema in children and is associated with an increased incidence of stroke in adults. The mechanism of these events is poorly understood. Posterior reversible encephalopathy syndrome (PRES) is seen in association with infection/sepsis, and cerebral vasculopathy has been demonstrated in PRES. We describe a case of PRES that develops in association with influenza A., Summary of Case: A normotensive 65-year-old woman presented with altered mentation and nausea in the setting of a viral prodromal illness ultimately confirmed as influenza A. Posterior reversible encephalopathy syndrome developed on the second day after admission. Catheter cerebral angiogram documented vasculopathy in PRES-involved regions with areas of focal vessel dilatation and string-of-bead appearance., Conclusions: The association between influenza A and PRES with documentation of cerebral vasculopathy suggests a common systemic vascular mechanism behind PRES and influenza-related encephalopathic edema and stroke.

Background and Purpose: Hemorrhage is known to occur in posterior reversible encephalopathy syndrome (PRES), but the characteristics have not been analyzed in detail. The purpose of this study was to evaluate the imaging and clinical features of hemorrhage in PRES., Materials and Methods: Retrospective assessment of 151 patients with PRES was performed, and 23 patients were identified who had intracranial hemorrhage at toxicity. Hemorrhage types were identified and tabulated, including minute focal hemorrhages (<5 mm), sulcal subarachnoid hemorrhage, and focal hematoma. Clinical features of hemorrhage and nonhemorrhage PRES groups were evaluated, including toxicity blood pressure, coagulation profile/platelet counts, coagulation-altering medication, and clinical conditions associated with PRES. Toxicity mean arterial pressure (MAP) groups were defined as normal (<106 mm Hg), mildly hypertensive (106-116 mm Hg), or severely hypertensive (>116 mm Hg)., Results: The overall incidence of hemorrhage was 15.2%, with borderline statistical significance noted between the observed clinical associations (P = .07). Hemorrhage was significantly more common (P = .02) after allogeneic bone marrow transplantation (allo-BMT) than after solid-organ transplantation. The 3 hemorrhage types were noted with equal frequency. A single hemorrhage type was found in 16 patients, with multiple types noted in 7. Patients undergoing therapeutic anticoagulation were statistically more likely to develop hemorrhage (P = .04). No difference in hemorrhage incidence was found among the 3 blood pressure subgroups (range, 14.9%-15.9%)., Conclusions: Three distinct types of hemorrhage (minute hemorrhage, sulcal subarachnoid hemorrhage, hematoma) were identified in PRES with equal frequency. The greatest hemorrhage frequency was seen after allo-BMT and in patients undergoing therapeutic anticoagulation. Hemorrhage rate was independent of the toxicity blood pressure.

Successful treatment of a patient's spine-related pain depends on accurate targeting of its location and cause. At a basic level, a focused history and physical examination is essential. Understanding of spine anatomy, in particular, spine innervation, is fundamental. Correlation with preprocedure imaging is important to confirm the suspected location(s) of the pain generator and is helpful in planning the approach for image-guided treatment. Understanding the variations in spine anatomy, subtle imaging features, or correlates of root irritation and factors that can affect the patient's presentation at the time of treatment are also critical to accurate targeting and effective treatment. This section reviews the fundamental elements that play a role in accurate diagnosis of the cause of a patient's spine-related pain. Routine application of these basic principles should aid in the approach to the spine-related pain patient and improve both accurate targeting of a patient's pain generator and the outcomes of image-guided treatment.

Epidural steroid injections and lumbar nerve root block/steroid injection are commonly performed interventional treatments for spine-related pain. These procedures are the foundation of any image-guided spine pain management practice. While more generic and not target-specific, epidural steroid injections are highly effective in a large proportion of patients, including patients with axial pain (neck or low back pain), radiculopathy, or spinal stenosis with neurogenic claudication. When isolated lumbar nerve root irritation is more clearly suspected, transforaminal nerve root blocks can provide useful diagnostic information as well as deliver more specifically targeted steroid treatment. Sustained pain relief can be achieved in a substantial number of patients with both types of procedure. Here we review the clinical indications and technical approach to these fundamental image-guided procedures. Fluoroscopy can be the routine approach to all injections. Computed tomography or computed tomographic fluoroscopy can be used as the primary approach in lumbar epidural or nerve root injections or be used as an alternative technique in unique cases. While the basic technical approach to epidural steroid administration in the cervical, thoracic, and lumbar regions is similar, each region has unique issues that must be addressed.

Reversible encephalopathy after transplantation is well recognized. The condition is commonly thought to be related to immune suppression, and a characteristic brain imaging pattern is typically recognized with vasogenic edema in the parietal and occipital regions, typically termed posterior reversible encephalopathy syndrome (PRES). We report the case of a patient with reversible encephalopathy after cardiac transplantation with brain biopsy evidence of endothelial activation, selective intravascular/perivascular T-cell trafficking, and VEGF expression in astrocytes, neurons, and the endothelium.

Facet and sacroiliac joint arthropathy are common, specific causes of low back pain. With a combination of a focused physical examination and image guidance, pain originating from these joints can be accurately targeted and these joints respond well to the direct application of long-acting deposition preparation steroids. When routine steroid treatment of the facet joint is not effective and more advanced treatment is required, denervation of the facet joint through the use of radiofrequency ablation (RFA) is a preferred method. Image guidance is a critical tool in targeting facet joint innervation, performing a central role in the techniques used in both preprocedure testing and the RFA treatment. This article reviews the basic image-guided fluoroscopic and computed tomographic-guided approaches to steroid treatment of the facet and sacroiliac joints and further discusses of the painful facet through RFA.

The diagnosis of diskogenic low back pain (LBP) can be elusive. Physical examination of the lumbar disk is limited and imaging offers few objective clues. While invasive, lumbar diskography is a method available to examine or "provoke" the disk directly and determine if LBP is coming from a disk and which disk(s) is responsible for the pain. Once identified, features of the abnormal disk can be evaluated, including the disk's response to intradiskal local anesthetic and disk architecture as observed on diskography imaging and postdiskogram computed tomography. Response to anesthetic can be correlated with imaging features potentially impacting treatment but can also stand alone as an independent objective marker of diskogenic LBP. Here we review the indications for lumbar diskography and the basic lumbar diskogram procedure. We also review the alternative more advanced technique for studying the anesthetic and mechanical features of the disk, functional anesthetic diskography.

Summary: First described in 1928, percutaneous aspiration of syringomyelia is infrequently performed to aid in diagnosis and surgical management. We describe a case of post traumatic syringomyelia successfully treated with direct fluoroscopic drainage with substantial resolution of syrinx-related neurologic symptoms. The patient is a 36-year-old man involved in a motorcycle accident who sustained multiple vertebral fractures resulting in dense paraplegia below T4, ultimately treated with multilevel laminectomy and pedicle screw fixation. The patient began to experience phantom leg paresthesias and muscle spasm felt to be related to an extensive spinal cord syrinx extending to the conus. Syrinx drainage was accomplished fluoroscopically at the level of the conus by percuntaneous needle drainage after cord localization with intrathecal myelographic contrast. Clear spinal fluid was drained from the syrinx cavity without complication. Immediately during and after drainage, the patient recognized a decrease in phantom pelvic and lower extremity paresthesias with significantly reduced spasticity. Syrinx collapse was documented with post-drainage CT imaging. Sustained relief of paresthesias and muscle spasms was achieved with gradual syrinx and symptom return requiring subsequent drainages performed at nine, 22 and 37 months following the initial drainage. In addition to confirming the symptomatic nature of syringomyelia in those with atypical symptoms, fluoroscopically guided drainage of syrinx can in select instances provide sustained relief. This modality may have additional advantages including serving as an adjunctive maneuver to improve operative access to the subarachnoid space by collapsing the cord, and serving as a temporizing measure for those patients who are poor surgical candidates. Maneuvers such as fluoroscopic table angulation provide an additional benefit in both the localization and drainage of syringomyelia and thus may be preferred over other minimally invasive procedures such as CT-guided drainage.

Background and Purpose: At lumbar diskography, intradiskal lidocaine can eliminate or reduce provoked diskogenic pain. The purpose of this study was to evaluate the postdiskogram CT features of lidocaine-sensitive and lidocaine-insensitive severely painful disks., Materials and Methods: Intradiskal lidocaine was injected at 182 severely painful levels in 111 patients. Clinical records/imaging studies were reviewed for response to intradiskal lidocaine (complete/substantial, partial, and no pain improvement), evidence of diskographic contrast leakage (fluoroscopic/CT images), and the overall postdiskogram CT appearance in these severely painful disks. The assessed traditional Dallas grade (degeneration/radial tear [RT]) was supplemented by identified postdiskogram CT features of annular derangement (annular gap [AG], RT into peripheral annular tear [PAT], isolated PAT, lamellar annular tear, free/attached annular fragments, bucket-handle tear, and peripheral annular pocket)., Results: Isolated degenerative changes (40%) and radial defects with or without degeneration (60%) subsets were noted. Dallas grade 3 degeneration was most commonly observed (69%) with increased features of annular derangement in disks with a worsening Dallas grade. Complete/substantial versus no pain improvement was significantly associated with disk state (diskographic leakage, contained), radial defect (none, RT, or AG), and "RT-into-PAT" and were statistically significant in univariate models (P < .001). The associations remained significant in multivariate models. Higher Dallas degenerative grade and presence of free annular fragments were associated with a greater chance of no pain relief., Conclusion: Severely painful disks demonstrated complex annular derangement with both radial defects (RTs and AGs) or degenerative changes present, alone or in combination. Complete/substantial pain improvement after lidocaine administration is associated with disk state, radial defect (RT and AG), and RT-into-PAT.

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state coupled with a unique CT or MR imaging appearance. Recognized in the setting of a number of complex conditions (preeclampsia/eclampsia, allogeneic bone marrow transplantation, organ transplantation, autoimmune disease and high dose chemotherapy) the imaging, clinical and laboratory features of this toxic state are becoming better elucidated. This review summarizes the basic and advanced imaging features of PRES, along with pertinent features of the clinical and laboratory presentation and available histopathology. Many common imaging/clinical/laboratory observations are present among these patients, despite the perception of widely different associated clinical conditions.

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state accompanied by a unique brain imaging pattern typically associated with a number of complex clinical conditions including: preeclampsia/eclampsia, allogeneic bone marrow transplantation, solid organ transplantation, autoimmune diseases and high dose cancer chemotherapy. The mechanism behind the developing vasogenic edema and CT or MR imaging appearance of PRES is not known. Two theories have historically been proposed: 1) Severe hypertension leads to failed auto-regulation, subsequent hyperperfusion, with endothelial injury/vasogenic edema and; 2) vasoconstriction and hypoperfusion leads to brain ischemia and subsequent vasogenic edema. The strengths/weaknesses of these hypotheses are reviewed in a translational fashion including supporting evidence and current available imaging/clinical data related to the conditions that develop PRES. While the hypertension/hyperperfusion theory has been most popular, the conditions associated with PRES have a similar immune challenge present and develop a similar state of T-cell/endothelial cell activation that may be the basis of leukocyte trafficking and systemic/cerebral vasoconstriction. These systemic features along with current vascular and perfusion imaging features in PRES appear to render strong support for the older theory of vasoconstriction coupled with hypoperfusion as the mechanism.

Background and Purpose: Posterior reversible encephalopathy syndrome (PRES) is known to occur after solid organ transplantation (SOT), potentially associated with cyclosporine and tacrolimus. In this study, we assess the frequency and clinical and imaging characteristics of PRES after SOT., Materials and Methods: We identified 27 patients (13 men and 14 women; age range, 22-72 years) who developed PRES after SOT. Features noted included SOT subtype, incidence and timing of PRES, infection and rejection, mean arterial pressure (MAP), and toxicity brain edema., Results: PRES developed in 21 (0.49%) of 4222 patients who underwent transplantation within the study period (no significant difference among SOT subtypes). Transplantation was performed in 5 patients before the study period, and 1 patient underwent transplantation elsewhere. In consideration of all 27 patients, PRES typically developed in the first 2 months in patients who had SOT of the liver (9 of 10 patients) and was associated with cytomegalovirus (CMV), mild rejection, or systemic bacterial infection. PRES also typically developed after 1 year in patients who had SOT of the kidney (8 of 9 patients) and was associated with moderate rejection or bacterial infection. Toxicity MAP was significantly lower (P < .001) in liver transplants (average MAP, 104.8 +/- 16 mm Hg) compared with that in kidney transplants (average MAP, 143 +/- 20 mm Hg). Toxicity brain edema was significantly greater (P < .001) in patients who had liver transplants and developed PRES compared with patients who had undergone kidney transplants despite severe hypertension in those who had the kidney transplants., Conclusion: Patients who had undergone SOTs have a similar low incidence of developing PRES. Differences between those who have had liver and kidney transplants included time after transplant, toxicity MAP, and PRES vasogenic edema noted at presentation. In patients who have undergone kidney transplants, severely elevated MAP was associated with reduced, not greater, brain edema.

Background and Purpose: The cause of posterior reversible encephalopathy syndrome (PRES) is unknown. Two primary hypotheses exist: 1) hypertension exceeding auto-regulatory limits leading to forced hyper-perfusion and 2) vasoconstriction and hypo-perfusion leading to ischemia with resultant edema. The purpose of this study was to evaluate the catheter angiography (CA), MR angiography (MRA), and MR perfusion (MRP) features in PRES in order to render further insight into its mechanism of origin., Materials and Methods: In 47 patients with PRES, 9 CAs and 43 MRAs were evaluated for evidence of vasculopathy (vasoconstriction and vasodilation), and 15 MRP studies were evaluated for altered relative cerebral blood volume (rCBV) in PRES lesions and regions. Visualization of vessels on MRA and toxicity blood pressures were compared with the extent of hemispheric vasogenic edema., Results: Vasculopathy was present in 8 of 9 patients on CA (direct correlation to MRA in 3/6 patients). At MRA, moderate to severe vessel irregularity consistent with vasoconstriction and vasodilation was present in 30 of 43 patients and vessel pruning or irregularity in 7 patients, with follow-up MRA demonstrating reversal of vasoconstriction or vasodilation in 9 of 11 patients. Vasogenic edema was less in patients with hypertension compared with patients who were normotensive. Preserved normal length of the posterior cerebral artery (PCA) was commonly seen in patients with severe hypertension despite diffuse or focal vasoconstriction or vasodilation. In these patients, lengthier visualization of the distal PCA correlated with a lower grade of hemispheric edema (P = .002). Cortical rCBV was significantly reduced in 51 of 59 PRES lesions and regions compared with a healthy reference cortex (average 61% of reference cortex) with mild decrease in the remainder., Conclusion: Vasculopathy was a common finding on CA and MRA in our patients with PRES, and MRP demonstrated reduced cortical rCBV in PRES lesions. Vasogenic edema was reduced in patients with hypertension, and superior distal PCA visualization correlated with reduced hemispheric edema in patients with PRES and severe hypertension.

Background and Purpose: Although the term posterior reversible encephalopathy syndrome (PRES) was popularized because of the typical presence of vasogenic edema in the parietal and occipital lobes, other regions of the brain are also frequently affected. We evaluated lesion distribution with CT and MR in a large cohort of patients who experienced PRES to comprehensively assess the imaging patterns identified., Materials and Methods: The locations of the PRES lesion at toxicity were comprehensively identified and tabulated in 136 patients by CT (22 patients) and MR (114 patients) imaging including the hemispheric, basal ganglial, and infratentorial locations. Clinical associations along with presentation at toxicity including blood pressure were assessed., Results: Vasogenic edema was consistently present in the parietal or occipital regions (98%), but other locations were common including the frontal lobes (68%), inferior temporal lobes (40%), and cerebellar hemispheres (30%). Involvement of the basal ganglia (14%), brain stem (13%), and deep white matter (18%) including the splenium (10%) was not rare. Three major patterns of PRES were noted: the holohemispheric watershed (23%), superior frontal sulcal (27%), and dominant parietal-occipital (22%), with additional common partial or asymmetric expression of these primary PRES patterns (28%)., Conclusion: Involvement of the frontal lobe, temporal lobe, and cerebellar hemispheres is common in PRES, along with the occasional presence of lesions in the brain stem, basal ganglia, deep white matter, and splenium. Three primary PRES patterns are noted in the cerebral hemispheres, along with frequent partial or asymmetric expression of these PRES patterns. Awareness of these patterns and variations is important to recognize PRES neurotoxicity more accurately when present.

Background and Purpose: Our aim was to evaluate the relationship of pain reduction, after intradiskal lidocaine administration during provocation lumbar diskography, to the presence of contrast leakage on postdiskographic imaging., Materials and Methods: Intradiskal lidocaine was injected at 182 significantly painful disk levels in 111 patients. The clinical records and imaging studies were reviewed for response to the lidocaine injection and for the presence/absence of diskographic contrast leakage on postdiskographic images and CT. Pain response was assigned the following grades: 1) complete or substantial improvement, 2) partial improvement, or 3) no significant improvement after lidocaine administration. Fluoroscopic imaging and postdiskographic CT were evaluated for the presence or absence of contrast leakage., Results: Eighty-two (45%) significantly painful treated disks were contained, and 100 (55%) demonstrated contrast leakage. In leaking disks, 74 (74%) demonstrated complete or near-complete pain reduction after lidocaine administration, 15 (15%) demonstrated partial improvement, and 11 (11%) demonstrated no pain relief. In contained disks, 56 disks (69%) demonstrated no improvement after lidocaine administration, 9 (11%) demonstrating partial relief, and 17 (20%) demonstrated complete or substantial improvement. Results comparing leaking disks versus contained disks and complete versus no improvement were statistically significant (P<.001)., Conclusion: Painful disks exhibiting diskographic leakage tend to be highly responsive to intradiskal lidocaine administration, whereas painful disks without diskographic leakage tend not to improve. This observation has implications with respect to targeting the origin of a patient's back pain and may have specific implications with respect to choice of treatment.

Several distinct clinical syndromes can accompany low back pain in patients with lumbar spine abnormality. Developmental factors and any superimposed degenerative changes determine the size and configuration of the spinal canal, lateral recess, and neural foramen, and can affect the nerve roots. Somatic or referred pain may develop depending on the involved anatomic site and underlying pathology. Many times, but not always, MR imaging findings correlate with the clinical presentation. Combined analysis of the imaging and clinical findings may provide a more accurate and concise approach to the patient with low back pain.

We describe a method of performing lower cervical nerve root block (CNRB) with CT fluoroscopy in patients with large body habitus using the swimmer's position. This approach reduces image noise with acceptable visualization of vital structures and improved foraminal/root access. Anticipated use of the swimmer's position coupled with minimally modified radiation exposure parameters can limit radiation dose to operator/patient and reduce procedure time to match that of CNRB using CT fluoroscopy in typical patients.

In a retrospective review, 3 (3.8%) of 78 patients developed recurrent posterior reversible encephalopathy syndrome. Underlying clinical conditions included sickle cell disease, antibody-positive autoimmune disease, and allogeneic bone marrow transplantation. Infection (bacterial/viral) was suspected or documented in both episodes in all 3 patients. Evidence of endothelial injury (schistocyte formation and increased lactate dehydrogenase) was documented in all patients, and multiple organ dysfunction syndrome developed during the hospital course of all admissions.

Background and Purpose: The cause of "posterior reversible encephalopathy syndrome" (PRES) is not established. We recently encountered several patients who developed PRES in the setting of severe infection. In this study, we comprehensively reviewed the clinical and imaging features in a large cohort of patients who developed PRES, with particular attention to those with isolated infection, sepsis, or shock (I/S/S)., Methods: The clinical/imaging features of 106 patients who developed PRES were comprehensively evaluated. In 25 of these patients, PRES occurred in association with severe I/S/S separate from transplantation. The clinical/imaging features (computer tomography, MR imaging, and MR angiography [MRA]) of the patients with I/S/S were further evaluated, including organ/tissue/blood culture results, mean arterial blood pressure (MAP) at toxicity, extent of cerebral edema, and presence of vasospasm., Results: PRES occurred in association with I/S/S in 25 of 106 patients (23.6%), in addition to 4 other major clinical settings, including cyclosporine/FK-506 (post-transplant) neurotoxicity (46.2%), autoimmune disease (10.4%), postchemotherapy (3.7%), and eclampsia (10.4%). In the 25 patients with I/S/S, available cultures demonstrated a predominance of gram-positive organisms (84%). Blood pressure was "normal" at toxicity in 10 patients (MAP, 95 mm Hg); "severe" hypertension was present in 15 patients (MAP, 137 mm Hg). Extent of brain edema graded on imaging studies was greater in the normal MAP group compared with the severe hypertension group (P < .05). MRA demonstrated vasospasm in patients with severe hypertension and vessel "pruning" in the normal MAP group., Conclusion: Infection/sepsis/shock may be an important cause of PRES, particularly in relation to infection with gram-positive organisms.

Introduction: The purpose of this study was to compare the differences in gland enhancement, microlesion enhancement and gland-lesion contrast ratio in patient groups in which half-dose (HD), standard-dose (SD) and double-dose (DD) contrast medium was used in pituitary MR imaging., Methods: Pituitary gland enhancement and microlesion enhancement were measured and gland-lesion contrast ratios were calculated in 18 patients receiving HD (0.05 mmol/kg), 9 receiving SD (0.1 mmol/kg) and 13 receiving DD (0.2 mmol/kg) contrast medium. Gland enhancement and microlesion enhancement over baseline were determined employing DICOM region of interest measurements and compared after normalization to temporal lobe white matter. Contrast ratios and differences were also calculated and compared., Results: Gland enhancement and lesion enhancement were greater with larger contrast medium doses (gland: HD 50%, SD 99%, DD 132%; microlesion: HD 19%, SD 54%, DD 86%). The gland-lesion contrast ratios were similar with the three doses (25.6%), reflecting expected similar fractional contrast medium distributions in spite of different doses. The signal difference between gland and microlesion, therefore, was a fixed percentage of gland enhancement (DeltaS approximately 26%) with greater signal differences with larger contrast medium doses., Conclusion: Greater gland-to-lesion signal differences with larger contrast medium doses would likely improve pituitary microlesion visualization and margin characterization aiding in microlesion detection as well as preoperative planning.

Background and Purpose: Limited data exist on the natural history of thoracic kyphosis in elderly patients. The purpose of this study was to determine the statistical distribution of the thoracic kyphotic angle (TKA) measurement in older patients without vertebral body abnormalities when compared with a young population., Methods: The TKA was measured by Cobb angle on digital lateral chest radiographs in 90 patients >65 years of age, 60 patients 51-65 years of age, 67 patients 36-50 years of age, and 63 patients 18-35 years of age. Patients with vertebral compression, vertebral body angulation, congenital anomaly, or significant scoliosis were excluded., Results: In patients >65 years of age, average TKA was 41.9 degrees , but the distribution was unexpectedly bimodal, with a low mode at 28.3 degrees and an upper mode at 51.5 degrees (P < .001). Elderly women and men independently demonstrated a bimodal TKA distribution. Two-thirds of elderly women and half of elderly men had a TKA >40 degrees (upper mode). In young patients, average TKA was 26.8 degrees . In middle-aged patients, TKA was intermediate and nonbimodal., Conclusion: The TKA distribution in elderly patients (>65 years) without vertebral body abnormality is unexpectedly bimodal (non-normal distribution) with a subpopulation of patients significantly more affected by extreme kyphosis. Extreme thoracic kyphosis therefore occurs independently in a large subset of people, in the absence of vertebral wedge compression. The development of extreme thoracic kyphosis might contribute to excess biomechanical stress in the spine and may identify a population at risk for future vertebral compression fracture in particular at the thoracolumbar junction.

The "prong deflector" tool improves accuracy and ease of access to the cervical disk spaces for use in cervical diskography. The tool allows control, deflection, and stabilization of vital neck structures (carotid artery, thyroid cartilages and pharynx) while allowing fluoroscopic visualization during needle insertion without direct operator radiation exposure. Use of the prong deflector resulted in marked reduction of fluoroscopy per cervical level studied because of more rapid access to disk space.

Loss of air pressure resistance leads to a high rate (25.7%) of inaccurate needle-tip placement in the posterior soft tissues of the back during lumbar epidural steroid administration employing a 20-gauge Tuohy needle. Imaging and epidurogram are essential for confident identification of the lumbar epidural space to enable accurate location of steroid administration. Studies assessing efficacy of lumbar epidural steroid injection and individual patient treatments should ensure location of administration with epidurogram to enhance the validity of results.

Introduction: This study examines whether malignant disease under treatment influences the incidence of cyclosporine or FK-506 neurotoxicity after myeloablative conditioning and allogeneic bone marrow transplantation (allo-BMT)., Methods: Review of 290 patients who received myeloablative conditioning prior to allo-BMT and cyclosporine/FK-506 identified 21 (7.2%) patients with neurotoxicity confirmed by computed tomography or magnetic resonance. Underlying malignancy necessitating allo-BMT included leukemias (67%), lymphoma (10%), myelodysplastic syndrome (10%), and multiple myeloma (MM). Frequency of neurotoxicity by disease was compared., Results: The highest incidence of neurotoxicity was present with MM (25%), whereas the lowest incidence was present with lymphoma (2.7%). Other diseases demonstrated intermediate incidence, including acute leukemias (10%), myelodysplastic syndrome (6.4%), and chronic myelogenous leukemia (4.9%)., Conclusion: Cyclosporine/FK-506 neurotoxicity varied according to the underlying malignancy. The variable susceptibility to the development of neurotoxicity in this population may depend on the interaction of host vasculature with disease specific factors. Understanding the cause of neurotoxicity could improve survival after allo-BMT.

Background and Purpose: Transplantation conditioning regimens have been shown to affect the brain imaging appearance in patients with cyclosporine or FK-506 neurotoxicity. We assessed whether the occurrence of neurotoxicity was affected by the choice of conditioning regimen used before allogeneic bone marrow transplantation (allo-BMT)., Methods: An allo-BMT was performed in 290 patients conditioned before transplantation with myeloablative therapy. Neurotoxicity from cyclosporine or FK-506 developed in 21 (7.2%) of these patients, as confirmed with CT or MR imaging. Two hundred seventy-four (94%) of these 290 patients were conditioned with minor variations of one of five fundamental regimens: cyclophosphamide (Cy)/busulfan (n = 97), Cy/total body irradiation (TBI) (n = 122), Cy/thiotepa/TBI (n = 40), bischloroethylnitrosourea/etoposide/cytarabine/melphalan, or BEAM (n = 10), and Cy/thiotepa/busulfan (n = 5). The remaining 16 patients were prepared with variable regimens. The rates of occurrence of cyclosporine or FK-506 neurotoxicity relative to these conditioning regimens were compared., Results: The lowest rate of cyclosporine or FK-506 neurotoxicity was found in those patients conditioned with Cy (2 days)/busulfan (4 days) (5.1%) or Cy (2 days)/TBI (4 days) (5.9%). Rate of neurotoxicity increased with lengthier conditioning regimens. A high rate of neurotoxicity was present in those patients conditioned with Cy (4 days)/TBI (4 days) (13.7%), and this was statistically significant (P <.05) when compared with Cy (2 days)/busulfan (4 days)., Conclusion: The rate of occurrence of cyclosporine or FK-506 neurotoxicity varies with the conditioning regimen used, with lengthier regimens associated with a higher rate of neurotoxicity. As the length of the conditioning regimen equates to the total dose of chemotherapy administered, it suggests that the intensity of the regimen is correlated to the predisposition to neurotoxicity from cyclosporine or FK-506.

Computed tomography and magnetic resonance imaging findings consistent with eclampsia were recently encountered in 3 patients who developed severe headache days to weeks after uncomplicated delivery. The neurologic presentation was nonspecific, and pre-eclamptic symptoms were not present, including significant hypertension. Variable expression of pre-eclampsia occurred during the course of their observation. Conventional angiography obtained in 2 patients because of a concern for aneurysm demonstrated central and peripheral vasospasm. Magnetic resonance angiography demonstrated central vasospasm in the third patient.

Background and Purpose: Previous authors have shown that conventional myelography is superior to plain CT in the assessment of root compression in the lateral recess, but this question has never been evaluated with respect to MR imaging of the lumbar level. Our purpose was to assess the accuracy of MR imaging, conventional myelography, and postmyelography CT (CT myelography) of the lumbar level in identifying degenerative lateral recess root compression with surgical confirmation., Methods: MR imaging, conventional myelography, and CT myelography of the lumbar level were assessed in the imaging of 58 lateral recesses at 38 lumbar levels in 26 patients who underwent surgery for radiculopathy with degenerative lateral recess abnormality. Each lateral recess was graded as normal, small without root compression, small with root compression, or severe root compression., Results: MR imaging underestimated root compression in 28% to 29% of the cases in which root impingement was surgically confirmed. Conventional myelography underestimated root compression in only 5% to 7% of the cases and correctly predicted impingement in 93% to 95%. CT myelography underestimated root compression in 38% of the surgically confirmed cases., Conclusion: MR imaging significantly underestimated root compression caused by degenerative changes in the lateral recess. Although MR imaging is a superb study when used in the search for degenerative disk disease and disk protrusion, conventional myelography is a crucial supplemental study that is necessary to confirm degenerative root impingement in the lateral recess as the cause of radiculopathy.

Background and Purpose: The etiology of the neurotoxicity associated with cyclosporin-A (CsA) and FK-506 treatment is not fully understood. At our institution, we noticed a distinct, abrupt change in the imaging characteristics of CsA and FK-506 neurotoxicity, which consisted of a shift in lesion morphology from a white matter abnormality to a mixed cortical and white matter pattern. The purpose of this study was to assess clinical parameters that might explain this change., Methods: Twenty-two patients had a neurotoxic reaction and brain imaging changes while receiving CsA or FK-506. Nineteen patients received allogeneic bone marrow transplants, and three had aplastic marrow disorders. Fifty-one imaging studies (CT or MR imaging) were obtained, and lesion characteristics, locations, and time courses were evaluated along with relevant clinical data., Results: Nine patients who had been conditioned for transplantation with cyclophosphamide and chemotherapy (busulfan or thiotepa) had a mixed pattern of cortical and white matter involvement (57 lesions). Isolated white matter involvement (62 lesions) developed in three nontransplant patients and 10 transplant patients conditioned with cyclophosphamide and total-body irradiation. All lesions occurred at typical brain watershed zones. Lesion enhancement was noted in two patients conditioned with chemotherapy. Initial images demonstrated characteristic lesions in 15 patients (68%). Initial images were normal in four patients (18%) and nonspecific in three patients (14%)., Conclusion: Lesion location in CsA and FK-506 neurotoxicity may depend on the presence or type of conditioning used before bone marrow transplantation. Nontransplant patients or those conditioned with total-body irradiation develop white matter lesions, whereas those conditioned with chemotherapy develop mixed cortical and white matter lesions.

We describe the adult radiographic shuntogram, a simple method to evaluate the function and patency of a ventriculoperitoneal or ventriculoatrial shunt. The procedure involves placing contrast material into the valve of a shunt system and following the flow for appropriate clearing of contrast agent from the shunt tubing. Twenty-three studies were obtained in 15 patients in whom shunt malfunction was suspected. The method can be used to establish valve malfunction, ventricular or distal catheter obstruction, and peritoneal encystment.

Purpose: The purpose of our study was to assess whether the imaging and clinical features of cyclosporin A (CsA) neurotoxicity support a vascular "watershed" cause for the brain lesions observed., Method: Fourteen patients receiving CsA after allogeneic bone marrow transplantation or with marrow aplastic disorders developed neurotoxicity and MR or CT imaging abnormalities. The locations of brain lesions were analyzed, and clinical features, in particular bone marrow transplant thrombotic microangiopathy (BMT-TM), were assessed., Results: Sixty-six lesions had consistent locations in watershed zones between major cerebral vessels or their main branches, including the parietal area (19), occipital poles (18), frontoparietal junction (15), inferior temporooccipital junction (10), and cerebellum (3). BMT-TM was identified in 10 of 10 marrow transplant patients studied., Conclusion: Vascular injury, suggested from watershed location and BMT-TM, likely establishes the location of the brain lesions in CsA neurotoxicity. Secondary toxicity in these vulnerable regions may cause the white matter lesions.

Purpose: To determine whether dynamic traditional spin-echo MR imaging, with the use of routine T1 parameters during contrast infusion, is superior to standard MR imaging after contrast administration for detecting microlesions of the pituitary gland., Methods: Sixty-four patients with pituitary microlesions 3 to 10 mm in diameter were examined with a dynamic traditional spin-echo technique; that is, a typical T1 spin-echo sequence of 500-600/20-25/2 (repetition time/echo time/excitations), 3-mm-thick sections, 16-cm field of view, 256 x 128 matrix, and a scan time ranging from 2 minutes to 2 minutes 40 seconds during contrast infusion. In addition, standard imaging with unenhanced and contrast-enhanced spin-echo sequences were obtained. The three sequences were evaluated retrospectively and graded for gland-lesion contrast conspicuity, lesion homogeneity, and delineation of lesion margin., Results: The dynamic sequence was judged to be better than the standard enhanced sequence for depicting microlesions in 42% to 47% of patients. Lesions were identified only on the dynamic study in an additional 1% to 14% of patients. Lesions were seen equally well on the standard and dynamic sequences only in 16% to 23% of cases. The standard postcontrast sequence was judged better in 12.5% to 17% of cases, with lesions identified only on the standard sequence in an additional 8% to 9%., Conclusion: Dynamic traditional spin-echo MR imaging improved lesion detection and provided increased clarity over standard sequences after contrast infusion. Both sequences are important, since lesions were detected only on the dynamic sequence in 11% to 14% of patients and only on the standard sequence in 8% to 9% of patients.

Eight infants with radiographic and bone biopsy evidence of autosomal recessive osteopetrosis were evaluated by cranial CT. The clinical presentations and CT characteristics support the theory that this disorder exhibits severe and mild variants. At an early stage the severe variant demonstrates small optic canals, small orbits with proptosis, and a small nasoethmoid complex without significant bone thickening. The paranasal sinuses show bud formation but no pneumatization. The temporal bone retains a fetal appearance with trumpet-shaped internal auditory canals, prominent subarcuate fossae, and no mastoid pneumatization. The ventricles and subarachnoid spaces are enlarged. Bone thickness increases with age, leading to further orbital encroachment. Similar but less severe features are present in the mild variant. Underdevelopment of the orbits, nasoethmoid complex, and temporal bone suggests that delayed maturation is the primary morphologic abnormality of the skull base in osteopetrosis, and that bone thickening is a secondary manifestation caused by reduced bone turnover.

A laboratory model of an arteriovenous malformation has been developed. Embolizations of the model were successfully performed under fluoroscopic guidance with collagen particles and cyanoacrylate liquid polymer. The model is inexpensive, easy to construct, and reduces the need for laboratory animals.

Air within the cavernous sinus resulting from fracture of the wall of the sphenoid sinus was identified by cranial CT in a patient with head injury. Careful search of the skull base is important in post-traumatic pneumocephalus to identify a potential site of CSF leak.