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Background and Purpose: Various imaging techniques have been described to detect CSF-venous fistulas in the setting of spontaneous intracranial hypotension, including decubitus CT myelography. The expected diagnostic yield of decubitus CT myelography for CSF-venous fistula detection is not fully established. The purpose of this study was to assess the yield of decubitus CT myelography among consecutive patients presenting for evaluation of possible spontaneous intracranial hypotension and to examine the impact of brain MR imaging findings of spontaneous intracranial hypotension on the diagnostic yield., Materials and Methods: The study included a single-center, retrospective cohort of consecutive patients presenting during a 1-year period who underwent CT myelography and had no CSF identified in the epidural space. Patients with epidural CSF leaks were included in a secondary cohort. Subjects were grouped according to positioning for the myelogram, either decubitus or prone, and the presence of imaging findings of spontaneous intracranial hypotension on preprocedural brain MR imaging. Diagnostic yields for each subgroup were calculated, and the yield of decubitus CT myelography was compared with that of prone CT myelography., Results: The study cohort comprised 302 subjects, including 247 patients with no epidural fluid. The diagnostic yield of decubitus CT myelography for CSF-venous fistula detection among subjects with positive brain MR imaging findings and no epidural fluid was 73%. No CSF-venous fistulas were identified among subjects with negative findings on brain imaging. Among subjects with an epidural leak, brain MR imaging was negative for signs of spontaneous intracranial hypotension in 22%. Prone CT myelography identified a CSF-venous fistula less commonly than decubitus CT myelography (43% versus 73%, P  = .19), though the difference was not statistically significant in this small subgroup., Conclusions: We found the diagnostic yield of decubitus CT myelography to be similar to the yield previously reported for digital subtraction myelography among patients with positive findings on brain imaging. No CSF-venous fistulas were identified in patients with negative findings on brain imaging; epidural CSF leaks accounted for all cases of patients who had spontaneous intracranial hypotension with negative brain imaging findings. This study provides useful data for counseling patients and helps establish a general benchmark for the decubitus CT myelography yield for CSF-venous fistula detection., (© 2024 by American Journal of Neuroradiology.)

Background and Purpose: The conspicuity of CSF-venous fistulas (CVF) on specialized myelographic imaging protocols varies, and the factors that determine their visibility have not yet been extensively studied. The purpose of this study was to determine the relative effect of two variables on CVF visibility: timing of imaging and intrathecal contrast density., Materials and Methods: Retrospective cohort of 24 patients with spontaneous intracranial hypotension due to a CVF who underwent a total of 34 CT myelographies. All CTM acquisitions that included the level of the known definite CVF were evaluated for (1) time passed after injection of contrast, (2) attenuation of the adjacent subarachnoid space, (3) subjective visibility of the CVF on that series,(4) attenuation of the corresponding draining vein and (5) contrast dose used., Results: A total of 131 acquisitions included the level of the known CVFs. Attenuation values of the thecal sac were significantly higher in acquisitions where the CVFs were definitely visible (average 2283 HU) than on acquisitions where the CVFs were equivocal or not visible (764 HU and 583 HU respectively). No significant difference was shown in the timing of the acquisitions between the three groups (12.8 min, 20.4 min and 17.5 min respectively). Multivariate linear regression showed thecal sac density to be the only independent predictor of the density of the CVF draining vein, while time passed after contrast injection was not independently correlated., Conclusions: Intrathecal contrast density has a strong positive relationship with the visibility of CVF. Timing of the acquisition was not an independent predictor of CVF visibility under our acquisition protocolABBREVIATIONS: LDCTM = lateral decubitus CT myelography; CVF = CSF-venous fistula; IOCM = iodinated contrast media., Competing Interests: The authors declare no conflicts of interest related to the content of this article., (© 2024 by American Journal of Neuroradiology.)

Background and Purpose: Early opacification of the renal collecting system during CT myelography (CTM) performed for the evaluation of Spontaneous Intracranial Hypotension (SIH) has been demonstrated in prior studies. However, these investigations often included CTMs scanned >30 minutes after intrathecal contrast injection, a longer delay than the myelographic techniques used in current practice. The purpose of this study was to determine whether renal contrast excretion (RCE) measured during this earlier time period (≤30 minutes) can discriminate patients with SIH from patients without SIH., Materials and Methods: Single-center, retrospective cohort of consecutive patients presenting for evaluation of possible SIH between July 2021-May 2022. RCE was measured in both renal hila using standardized (5-15mm 3 ) ROIs. ROC curves were constructed comparing RCE between patients with SIH to patients without SIH in the overall cohort, and within the subgroup of patients with negative myelograms., Results: The study cohort included 190 subjects. Both unadjusted and adjusted models demonstrated a statistically significant increase in renal contrast density among patients with SIH compared to those without SIH (p-values ≤ 0.001). The ROC curve showed moderate discrimination between these groups (AUC 0.76). However, using clinically meaningful test criteria of sensitivity >90% or specificity >90%, the two corresponding threshold HU values resulted in low specificity of 31.3% and sensitivity of 50.8%. Subgroup analysis of patients with negative myelograms showed poorer performance in discriminating SIH+ from SIH- (AUC 0.62). In this subgroup, using similar test criteria of sensitivity >90% or specificity >90 resulted in low specificities and sensitivities, at 26.0% and 37.5% respectively., Conclusions: We found a statistically significant positive association between RCE and SIH diagnosis during early-phase CTM, however clinically useful thresholds based on cutoff values for renal HU resulted in poor sensitivities or specificities, with substantial false positives or false negatives, respectively. Thus, while we confirmed statistically significant differences in RCE in the ≤30 min time period, in keeping with prior investigations of more delayed time periods, overlap in renal attenuation values prevented the development of clinically useful threshold value for discriminating SIH+ from SIH-patients., Abbreviations: SIH = spontaneous intracranial hypotension; RCE = renal contrast excretion; CTM = CT myelography; CVF = CSF-venous fistula; ICHD-3 = international classification of headache disorders third edition; CKD = chronic kidney disease., Competing Interests: The authors declare no conflicts of interest related to the content of this article., (© 2024 by American Journal of Neuroradiology.)

Background and Purpose: Lateral decubitus CT myelography (LDCTM) is one of the main studies for the detection of CSF-venous fistulas (CVF), but detection of CVFs is dependent on intrathecal contrast density. The purpose of this investigation was to assess tolerability and technical performance of increased intrathecal doses of myelographic contrast compared to standard doses., Materials and Methods: Retrospective series of 24 patients who underwent LDCTM following administration of either 10 or 20 ml of intrathecal iodinated contrast media (300 or 320mg/mL iodine content). Patients were scanned in the initial lateral decubitus position, then turned to the contralateral side and re-scanned in the same session. Safety and tolerability of the 20 ml dosage was assessed from clinical records. Technical performance of the studies was compared between groups by measuring attenuation values over the lateral thecal sac at standardized levels. Both the initial scan and the scan after turning to the contralateral side were assessed., Results: No moderate or severe adverse event was recorded in either group. The 20-ml group showed higher attenuation values, which were statistically greater on the second side examined compared to the standard-dose group., Conclusions: Increased volume of intrathecal contrast was well-tolerated and improved technical performance of LDCTM in this limited series. Further assessment of safety and impact on diagnostic yield using larger patient cohorts is warranted., Abbreviations: LDCTM = lateral decubitus CT myelography; CVF = CSF-venous fistula; IOCM = iodinated contrast media., Competing Interests: The authors declare no conflicts of interest related to the content of this article., (© 2024 by American Journal of Neuroradiology.)

BACKGROUND. CSF-venous fistulas (CVFs), which are an increasingly recognized cause of spontaneous intracranial hypotension (SIH), are often diminutive in size and exceedingly difficult to detect by conventional imaging. OBJECTIVE. This purpose of this study was to compare energy-integrating detector (EID) CT myelography and photon-counting detector (PCD) CT myelography in terms of image quality and diagnostic performance for detecting CVFs in patients with SIH. METHODS. This retrospective study included 38 patients (15 men and 23 women; mean age, 55 ± 10 [SD] years) with SIH who underwent both clinically indicated EID CT myelography (slice thickness, 0.625 mm) and PCD CT myelography (slice thickness, 0.2 mm; performed in ultrahigh-resolution mode) to assess for CSF leak. Three blinded radiologists reviewed examinations in random order, assessing image noise, discernibility of spinal nerve root sleeves, and overall image quality (each assessed using a scale of 0-100, with 100 denoting highest quality) and recording locations of the CVFs. Definite CVFs were defined as CVFs described in CT myelography reports using unequivocal language and having an attenuation value greater than 70 HU. RESULTS. For all readers, PCD CT myelography, in comparison with EID CT myelography, showed higher mean image noise (reader 1: 69.9 ± 18.5 [SD] vs 37.6 ± 15.2; reader 2: 59.5 ± 8.7 vs 49.3 ± 12.7; and reader 3: 57.6 ± 13.2 vs 42.1 ± 16.6), higher mean nerve root sleeve discernibility (reader 1: 81.6 ± 21.7 [SD] vs 30.4 ± 13.6; reader 2: 83.6 ± 10 vs 70.1 ± 18.9; and reader 3: 59.6 ± 13.5 vs 50.5 ± 14.4), and higher mean overall image quality (reader 1: 83.2 ± 20.0 [SD] vs 38.1 ± 13.5; reader 2: 80.1 ± 10.1 vs 72.4 ± 19.8; and reader 3: 57.8 ± 11.2 vs 51.9 ± 13.6) (all p < .05). Eleven patients had a definite CVF. Sensitivity and specificity of EID CT myelography and PCD CT myelography for the detection of definite CVF were 45% and 96% versus 64% and 85%, respectively, for reader 1; 36% and 100% versus 55% and 96%, respectively, for reader 2; and 57% and 100% versus 55% and 93%, respectively, for reader 3. The sensitivity was significantly higher for PCD CT myelography than for EID CT myelography for reader 1 and reader 2 (both p < .05) and was not significantly different between the two techniques for reader 3 ( p = .45); for all three readers, specificity was not significantly different between the two modalities (all p > .05). CONCLUSION. In comparison with EID CT myelography, PCD CT myelography yielded significantly improved image quality with significantly higher sensitivity for CVFs (for two of three readers), without significant loss of specificity. CLINICAL IMPACT. The findings support a potential role for PCD CT myelography in facilitating earlier diagnosis and targeted treatment of SIH, avoiding high morbidity during potentially prolonged diagnostic workups.

An expanding array of image-guided spine interventions have the potential to provide immediate and effective pain relief. Innovations in spine intervention have proceeded rapidly, with clinical adoption of new techniques at times occurring before the development of bodies of evidence to establish efficacy. Although new spine interventions have been evaluated by clinical trials, acceptance of results has been hindered by controversies regarding trial methodology. This article explores controversial aspects of four categories of image-guided interventions for painful conditions: spine interventions for postdural puncture headache resulting from prior lumbar procedures, epidural steroid injections for cervical and lumbar radiculopathy, interventions for facet and sacroiliac joint pain, and vertebral augmentations for compression fractures. For each intervention, we summarize the available literature, with an emphasis on persistent controversies, and discuss how current areas of disagreement and challenge may shape future research and innovation. Despite the ongoing areas of debate regarding various aspects of these procedures, effective treatments continue to emerge and show promise for aiding relief of a range of debilitating conditions.

DROSHA encodes a ribonuclease that is a subunit of the Microprocessor complex and is involved in the first step of microRNA (miRNA) biogenesis. To date, DROSHA has not yet been associated with a Mendelian disease. Here, we describe two individuals with profound intellectual disability, epilepsy, white matter atrophy, microcephaly and dysmorphic features, who carry damaging de novo heterozygous variants in DROSHA. DROSHA is constrained for missense variants and moderately intolerant to loss-of-function (o/e = 0.24). The loss of the fruit fly ortholog drosha causes developmental arrest and death in third instar larvae, a severe reduction in brain size and loss of imaginal discs in the larva. Loss of drosha in eye clones causes small and rough eyes in adult flies. One of the identified DROSHA variants (p.Asp1219Gly) behaves as a strong loss-of-function allele in flies, while another variant (p.Arg1342Trp) is less damaging in our assays. In worms, a knock-in that mimics the p.Asp1219Gly variant at a worm equivalent residue causes loss of miRNA expression and heterochronicity, a phenotype characteristic of the loss of miRNA. Together, our data show that the DROSHA variants found in the individuals presented here are damaging based on functional studies in model organisms and likely underlie the severe phenotype involving the nervous system., (© The Author(s) 2022. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: Spontaneous intracranial hypotension (SIH) is a debilitating disorder caused by non-iatrogenic spinal cerebrospinal fluid leaks. SIH is increasingly recognized as an important treatable cause of secondary headaches. Treatment involves either epidural blood patching or surgery, which have considerable differences in their adverse event rates, recovery times, and cost. The objective of this evidence map is to understand the breadth of studies that investigate SIH treatment efficacy and to identify knowledge gaps to inform future research., Methods: This review will consider experimental, observational, and systematic review studies that assess the efficacy of epidural blood patching and surgery for the treatment of patients with SIH. Individual case studies, clinical guidelines, editorials, protocols, and studies that do not assess an intervention will not be included. English language studies will be included without limitation based on the date of publication. Databases to be searched include MEDLINE® (via Ovid), EMBASE (via Elsevier), and Web of Science™ (via Clarivate). Study selection will be performed independently by two investigators with extracted data to include study type, the number of patients included, patient descriptors, intervention characteristics, and outcome measure used. Data will be presented through a narrative summary aided by tabular and graphical formats in a manner that aligns with the objective of the evidence mapping review., Discussion: The overarching goal of this evidence map is to provide an improved understanding of the breadth of studies investigating SIH treatment efficacy in the literature and to thereby identify knowledge gaps that can inform future research directions., Trial Registration: OSF Registry https://osf.io/nwju7 ., (© 2022. The Author(s).)

CSF-venous fistulas (CVFs), first described in 2014, are an important cause of spontaneous intracranial hypotension. CVFs can be challenging to detect on conventional anatomic imaging because, unlike other types of spinal CSF leak, they do not typically result in pooling of fluid in the epidural space, and imaging signs of CVF may be subtle. Specialized myelographic techniques have been developed to help with CVF identification, but these techniques are not yet widely disseminated. This article reviews the current understanding of CVFs, emphasizing correlations between venous anatomy and imaging findings as well as potential mechanisms for pathogenesis, and describes current imaging techniques used for CVF diagnosis and localization. These techniques are broadly classified into fluoroscopy-based methods, including digital subtraction myelography and dynamic myelography, and cross-sectional methods, including decubitus CT myelography and MR myelography with intrathecal injection of gadolinium. Knowledge of these various options, including their relative advantages and disadvantages, is critical in the care of patients with spontaneous intracranial hypotension. Investigation is ongoing, and continued advances in knowledge about CVFs as well as in optimal imaging detection are anticipated.

Objective: Chiari malformation type 1 (CM-1) and spontaneous intracranial hypotension (SIH) are causes of headache in which cerebellar tonsillar ectopia (TE) may be present. An accurate method for differentiating these conditions on imaging is needed to avoid diagnostic confusion. Here, the authors sought to determine whether objective measurements of midbrain morphology could distinguish CM-1 from SIH on brain MRI., Methods: This is a retrospective case-control series comparing neuroimaging in consecutive adult subjects with CM-1 and SIH. Measurements obtained from brain MRI included previously reported measures of brain sagging: TE, slope of the third ventricular floor (3VF), pontomesencephalic angle (PMA), mamillopontine distance, lateral ventricular angle, internal cerebral vein-vein of Galen angle, and displacement of iter (DOI). Clivus length (CL), an indicator of posterior fossa size, was also measured. Measurements for the CM-1 group were compared to those for the entire SIH population (SIHall) as well as a subgroup of SIH patients with > 5 mm of TE (SIHTE subgroup)., Results: Highly significant differences were observed between SIHall and CM-1 groups in the following measures: TE (mean ± standard deviation, 3.1 ± 5.7 vs 9.3 ± 3.5 mm), 3VF (-16.8° ± 11.2° vs -2.1° ± 4.6°), PMA (44.8° ± 13.1° vs 62.7° ± 9.8°), DOI (0.2 ± 4.1 vs 3.8 ± 1.6 mm), and CL (38.3 ± 4.5 vs 44.0 ± 3.3 mm; all p < 0.0001). Eight (16%) of 50 SIH subjects had TE > 5 mm; in this subgroup (SIHTE), a cutoff value of < -15° for 3VF and < 45° for PMA perfectly discriminated SIH from CM-1 (sensitivity and specificity = 1.0). DOI showed perfect specificity (1.0) in detecting SIH among both groups. No subjects with SIH had isolated TE without other concurrent findings of midbrain sagging., Conclusions: Measures of midbrain sagging, including cutoff values for 3VF and PMA, discriminate CM-1 from SIH and may help to prevent misdiagnosis and unnecessary surgery.

Background: Cerebrospinal fluid-venous fistula (CVF) is a recently described cause of spontaneous intracranial hypotension (SIH). Surgical ligation of CVF has been reported, but clinical outcomes are not well described., Objective: To determine the clinical efficacy of surgical ligation for treatment of CVF., Methods: Outcomes metrics were collected in this prospective, single-arm, cross-sectional investigation. Inclusion criteria were as follows: diagnosis of SIH, demonstration of CVF on myelography, and surgical treatment of CVF. Pre- and postoperative headache severity was assessed with the Headache Impact Test (HIT-6), a validated headache scale ranging from 36 (asymptomatic) to 78 (most severe). Patient satisfaction with treatment was measured with Patient Global Impression of Change (PGIC)., Results: Twenty subjects were enrolled, with mean postoperative follow-up at 16.0 ± 9.7 mo. All CVFs were located in the thoracic region (between T4 and T12). Pretreatment headache severity was high (mean HIT-6 scores 65 ± 6). Surgical treatment resulted in marked improvement in headache severity (mean HIT-6 change of -21 ± -9, mean postoperative HIT-6 of 44 ± 8). Of subjects with baseline headache scores in the most severe category, 83% showed a major improvement in severity (transition to the lowest 2 severity categories) after surgery. All subjects (100%) reported clinically significant levels of satisfaction with treatment (PGIC score 6 or 7); 90% reported the highest level of satisfaction. There were no short- or long-term complications or 30-d readmissions., Conclusion: Surgical ligation is highly effective for the treatment of SIH due to CVF. Larger controlled trials with longer follow-up period are indicated to better assess its long-term efficacy and safety profile., (Copyright © 2019 by the Congress of Neurological Surgeons.)

This article reviews the role of imaging in the diagnosis, management, and treatment of spontaneous intracranial hypotension (SIH). SIH is a debilitating and often misdiagnosed condition caused by either a spinal cerebrospinal fluid (CSF) leak or a CSF to venous fistula. This pathologic condition is identified and localized via spinal imaging, including computed tomographic (CT) myelography, dynamic myelography, dynamic (ultrafast) CT myelography, MR imaging, or MR myelography with intrathecal gadolinium. Treatment of SIH involves conservative measures, surgery, or imaging-guided epidural blood patching., (Published by Elsevier Inc.)

Objective: The purpose of this study was to assess the rate of inadvertent injection into the retrodural space of Okada during CT fluoroscopy-guided interlaminar epidural steroid injection in the cervical spine., Materials and Methods: Images from cases of cervical interlaminar epidural steroid injection under CT fluoroscopic guidance performed at a single institution between November 2009 and November 2015 were obtained and reviewed. For all cases, the following information was recorded: presence or absence of contrast material within the Okada space, cervical anatomic level at which the procedure was performed, laterality of approach, trainee presence, and years of proceduralist experience. Two-tailed chi-square tests were used to assess categoric variables, and t tests were performed to assess for continuous variables predictive of nontarget injection., Results: A total of 974 CT fluoroscopy-guided cervical interlaminar epidural steroid injections were identified in 728 patients. The presence of contrast material in the retrodural space of Okada was identified in 2.9% of cases (28/974). All cases of inadvertent injection were identified and corrected intraprocedurally. The greatest rate of inadvertent injection (4.6% [18/389]) occurred at C5-6. No variables predictive of inadvertent injection into the Okada space were identified. There was a 0.4% (4/974) complication rate, and all complications were minor., Conclusion: We identified a 2.9% rate of unintended injection into the retrodural space of Okada during cervical interlaminar epidural steroid injection. If unrecognized, these nontarget injections can result in treatment failure in a subset of patients who undergo cervical interlaminar epidural steroid injection. Future study is warranted to assess the rate of inadvertent Okada injection under conventional fluoroscopy and to compare the rates of detection between the two imaging-guided modalities.

The 17 genes of the T-box family are transcriptional regulators that are involved in all stages of embryonic development, including craniofacial, brain, heart, skeleton and immune system. Malformation syndromes have been linked to many of the T-box genes. For example, haploinsufficiency of TBX1 is responsible for many structural malformations in DiGeorge syndrome caused by a chromosome 22q11.2 deletion. We report four individuals with an overlapping spectrum of craniofacial dysmorphisms, cardiac anomalies, skeletal malformations, immune deficiency, endocrine abnormalities and developmental impairments, reminiscent of DiGeorge syndrome, who are heterozygotes for TBX2 variants. The p.R20Q variant is shared by three affected family members in an autosomal dominant manner; the fourth unrelated individual has a de novo p.R305H mutation. Bioinformatics analyses indicate that these variants are rare and predict them to be damaging. In vitro transcriptional assays in cultured cells show that both variants result in reduced transcriptional repressor activity of TBX2. We also show that the variants result in reduced protein levels of TBX2. Heterologous over-expression studies in Drosophila demonstrate that both p.R20Q and p.R305H function as partial loss-of-function alleles. Hence, these and other data suggest that TBX2 is a novel candidate gene for a new multisystem malformation disorder.

Objective: The objective of this study is to describe the anatomic and imaging features of CSF venous fistulas, which are a recently reported cause of spontaneous intracranial hypotension (SIH)., Materials and Methods: We retrospectively reviewed the records of patients with SIH caused by CSF venous fistulas who received treatment at our institution. The anatomic details of each fistula were recorded. Attenuation of the veins involved by the fistula was compared with that of adjacent control veins on CT myelography (CTM). Visibility of the CSF venous fistula on CTM and a modified conventional myelography technique we refer to as dynamic myelography was also compared., Results: Twenty-two cases of CSF venous fistula were identified. The fistulas were located between T4 and L1. Ninety percent occurred without a concurrent epidural CSF leak. In most cases (82%), the CSF venous fistula originated from a nerve root sleeve diverticulum. On CTM, the abnormal veins associated with the CSF venous fistula were seen in a paravertebral location in 45% of cases, centrally within the epidural venous plexus in 32%, and lateral to the spine in 23%. Differences in attenuation between the fistula veins and the control veins was highly statistically significant (p < 0.0001), with a threshold of 70 HU perfectly discriminating fistulas from normal veins in our series. When both CTM and dynamic myelography were performed, the fistula was identified on both modalities in 88% of cases., Conclusion: CSF venous fistulas are an important cause of SIH that can be detected on both CTM and dynamic myelograph y and may occur without an epidural CSF leak. Familiarity with the imaging characteristics of these lesions is critical to providing appropriate treatment to patients with SIH.

Objective: The objective of our study was to determine whether the presence of individual imaging signs of spontaneous intracranial hypotension (SIH) is correlated with increasing duration of headache symptoms. Of particular interest is the relationship of symptom duration to dural enhancement because it is the most commonly identified imaging sign in patients with SIH., Materials and Methods: Eighty-nine patients with SIH who underwent pretreatment brain MRI and total-spine CT myelography and whose medical record included data on the duration of clinical symptoms were included in this cross-sectional retrospective study. Brain imaging was reviewed for the presence of dural enhancement, brain sagging, and the "venous distention" sign. CT myelograms were assessed for CSF leak. If present, a leak was subcategorized as a high-flow or low-flow leak. Differences in headache duration between subjects with and those without individual imaging signs were compared., Results: Subjects without dural enhancement on brain MRI had a longer average duration of symptoms than those with dural enhancement present (average symptom duration: 45.3 ± 59.0 [SD] vs 15.1 ± 33.0 weeks, respectively; p = 0.002). No difference in symptom duration was observed between subjects whose MRI studies showed and those whose MRI studies did not show brain sagging (p = 0.10) or the venous distention sign (p = 0.21). The presence of a CSF leak on CT myelography was not associated with symptom duration (p = 0.56) except in the subgroup of patients with low-flow leaks., Conclusion: Increasing symptom duration in SIH is associated with decreased prevalence of abnormal dural enhancement on brain MRI. Because dural enhancement is considered a hallmark imaging feature of this condition, its absence may exacerbate the problem of underdiagnosis in chronic cases of SIH.

Objective: The purpose of this study is to describe the procedure for CT fluoroscopy-guided lumbar medial branch blocks and facet radiofrequency ablation., Conclusion: CT fluoroscopic guidance allows more-precise needle tip positioning and is an alternative method for performing medial branch blocks and facet radiofrequency ablation.

Objective: CT fluoroscopy-guided lumbar spine pain injections typically include a preprocedural planning CT that contributes considerably to patient dose. The purpose of this study was to quantify the degree of radiation exposure reduction achieved by modifying only the planning CT component of the examination., Materials and Methods: A retrospective review was performed of 80 CT fluoroscopy-guided lumbar spine injections. Forty patients were scanned with a standard protocol using automatic tube current modulation (method A). Another 40 patients were scanned using a new technique that fixed the tube current of the planning CT to either 50 or 100 mA on the basis of the patient's anteroposterior diameter and that reduced the z-axis coverage (method B). Dose-length products (DLPs) were compared for the two methods., Results: The mean maximal tube current for the planning CT was 435.0 mA for method A and 67.5 mA for method B. The mean z-axis was shorter for method B at 6.5 cm than for method A at 9.6 cm (p < 0.0001). The mean DLP for the planning CT was 11 times lower for method B than for method A: 27.9 versus 313.1 mGy × cm, respectively (p < 0.0001). When method B was used, the mean DLP for the total procedure (i.e., planning CT plus CT fluoroscopy components) was reduced by 78%. There was no significant difference between methods A and B in CT fluoroscopy time (p = 0.37). All procedures were technically successful., Conclusion: A nearly fivefold reduction in radiation exposure can be achieved in CT fluoroscopy-guided lumbar spine pain injections through modifications to the planning CT alone.

Objective: Spinal leakage of CSF causes almost all cases of spontaneous intracranial hypotension. Leak detection and localization are important for both diagnosis and treatment. The myelographic appearance of the leaks may vary, however, depending on the cause of the leak, rate of leakage, and imaging modality used., Conclusion: The purpose of this article is to review the imaging of spinal CSF leaks and to assist in the selection of appropriate imaging modalities in this condition.

Objective: The purpose of this study was to determine the number of thyroid nodule workups that could be eliminated and the number of malignant tumors that would be missed if the Society of Radiologists in Ultrasound (SRU) recommendations and the three-tiered system were applied to incidental thyroid nodules (ITN) detected at imaging., Materials and Methods: This retrospective study included ITN in 390 consecutively registered patients who underwent ultrasound-guided fine-needle aspiration of one or more thyroid nodules from July 2010 to June 2011. Images were reviewed, and nodules were categorized according to two workup criteria: ITN seen on ultrasound images were categorized according to SRU recommendations, and those seen on CT, MR, or PET/CT images were classified according to the three-tiered risk-categorization system., Results: In this study 114 of 390 (29%) patients had nodules first detected incidentally during imaging studies, and 107 patients met the inclusion criteria. These patients had 47 ITN seen at ultrasound and 60 ITN seen at either CT, MRI, or PET/CT. If the SRU recommendations had been applied, 14 of 47 (30%) patients with ITN on ultrasound images would not have received fine-needle aspiration and one of four cases of cancer would have been missed. The missed malignant tumor was a 14-mm localized papillary carcinoma. If the three-tiered system had been applied, 21 of 60 (35%) patients with ITN on CT, MR, or PET/CT images would not have received fine-needle aspiration, but none of the three malignancies would have been missed. Overall, 35 of 107 (33%) of patients with ITN did not meet the SRU recommendations or the three-tiered criteria., Conclusion: Use of the SRU recommendations and three-tiered system can reduce the workup of ITN by one third compared with current practice without specific guidelines. One case of localized papillary carcinoma was missed when the SRU recommendations were used.

Objective: We describe the use of CT fluoroscopy as a guidance tool for performing interlaminar epidural steroid injections in the cervical spine., Conclusion: CT fluoroscopy is an alternative method to perform cervical interlaminar steroid injections that allows precise needle placement in the epidural space.

Objective: The purpose of this article is to bring some of the potential causes of false-positive and false-negative interpretations of dural sinus thrombosis (DST) on cross-section imaging studies to the attention of radiologists., Conclusion: The prompt diagnosis of DST can be important in many cases and a false-positive diagnosis can cause a delay in establishing the correct diagnosis as well as lead to implementation of inappropriate therapy. We hope that this article helps to reduce the number of such cases in the daily practice of the reader.

Objective: CT fluoroscopy-assisted cervical transforaminal steroid injection is an effective therapeutic option for cervical radiculopathy, yet it is approached with trepidation by some interventionalists. CT fluoroscopy is superior to conventional fluoroscopy for delineating complex anatomic relations in the neck but must be combined with careful technique to avoid rare but serious complications. We describe the anatomy of the neural foramen, our technique of CT fluoroscopy-assisted cervical transforaminal steroid injection, and the CT appearance of appropriate and inappropriate needle positions., Conclusion: Understanding anatomy will help to avoid complications and optimize the therapeutic potential of cervical transforaminal steroid injection. Use of contrast material for CT fluoroscopic guidance facilitates appropriate needle positioning and reduces the risk of complications.