Diagnostic Role of Diffusion-Weighted and Dynamic Contrast-Enhanced Perfusion MR Imaging in Paragangliomas and Schwannomas in the Head and Neck.

BACKGROUND AND PURPOSE: Distinguishing schwannomas from paragangliomas in the head and neck and determining succinate dehydrogenase (SDH) mutation status in paragangliomas are clinically important. We aimed to assess the clinical usefulness of DWI and dynamic contrast-enhanced MR imaging in differentiating these 2 types of tumors, as well as the SDH mutation status of paragangliomas. MATERIALS AND METHODS: This retrospective study from June 2016 to June 2020 included 42 patients with 15 schwannomas and 27 paragangliomas (10 SDH mutation-positive and 17 SDH mutation-negative). ADC values, dynamic contrast-enhanced MRI parameters, and tumor imaging characteristics were compared between the 2 tumors and between the mutation statuses of paragangliomas as appropriate. Multivariate stepwise logistic regression analysis was performed to identify significant differences in these parameters. RESULTS: Fractional plasma volume (P ≤ .001), rate transfer constant (P = .038), time-to-maximum enhancement (P < .001), maximum signal-enhancement ratio (P < .001) and maximum concentration of contrast agent (P < .001), velocity of enhancement (P = .002), and tumor characteristics including the presence of flow voids (P = .001) and enhancement patterns (P = .027) showed significant differences between schwannomas and paragangliomas, though there was no significant difference in ADC values. In the multivariate logistic regression analysis, fractional plasma volume was identified as the most significant value for differentiation of the 2 tumor types (P = .014). ADC values were significantly higher in nonhereditary than in hereditary paragangliomas, while there was no difference in dynamic contrast-enhanced MR imaging parameters. CONCLUSIONS: Dynamic contrast-enhanced MR imaging parameters show promise in differentiating head and neck schwannomas and paragangliomas, while DWI can be useful in detecting SDH mutation status in paragangliomas.

Assessment of MR Imaging and CT in Differentiating Hereditary and Nonhereditary Paragangliomas.

BACKGROUND AND PURPOSE: Head and neck paragangliomas have been reported to be associated with mutations of the succinate dehydrogenase enzyme family. The aim of this study was to assess whether radiologic features could differentiate between paragangliomas in the head and neck positive and negative for the succinate dehydrogenase mutation. MATERIALS AND METHODS: This single-center retrospective review from January 2015 to January 2020 included 40 patients with 48 paragangliomas (30 tumors positive for succinate dehydrogenase mutation in 23 patients and 18 tumors negative for the succinate dehydrogenase mutation in 17 patients). ADC values and tumor characteristics on CT and MR imaging were evaluated by 2 radiologists. Differences between the 2 cohorts in the diagnostic performance of ADC and normalized ADC (ratio to ADC in the medulla oblongata) values were evaluated using the independent samples t test. P < .05 was considered significant. RESULTS: ADCmean (1.07 [SD, 0.25]/1.04 [SD, 0.12] versus 1.31 [SD, 0.16]/1.30 [SD, 0.20]× 10-3 mm2/s by radiologists 1 and 2; P < .001), ADCmaximum (1.49 [SD, 0.27]/1.49 [SD, 0.20] versus 2.01 [SD, 0.16]/1.87 [SD, 0.20] × 10-3 mm2/s; P < .001), normalized ADCmean (1.40 [SD, 0.33]/1.37 [SD, 0.16] versus 1.73 [SD, 0.22]/1.74 [SD, 0.27]; P < .001), and normalized ADCmaximum (1.95 [SD, 0.37]/1.97 [SD, 0.27] versus 2.64 [SD, 0.22]/2.48 [SD, 0.28]; P < .001) were significantly lower in succinate dehydrogenase mutation-positive than mutation-negative tumors. ADCminimum, normalized ADCminimum, and tumor characteristics were not statistically significant. CONCLUSIONS: ADC is a promising imaging biomarker that can help differentiate succinate dehydrogenase mutation-positive from mutation-negative paragangliomas in the head and neck.

Prognostic indices for cerebral venous thrombosis on CT perfusion: a prospective study.

PURPOSE: We determined the prognostic significance of CT perfusion characteristics of patients with cerebral venous sinus thrombosis (CVST) and assessed the change in perfusion parameters following anticoagulation therapy. MATERIALS AND METHODS: 20 patients with CVST diagnosed on non-contrast computed tomography (NCCT), magnetic resonance imaging (MRI), and magnetic resonance venography (MRV) were included in this study. The initial CT perfusion study was performed at the time of admission. The following perfusion parameters: relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), and relative mean transit time (rMTT) were calculated in the core and periphery of the affected area of the brain. Follow-up CT perfusion studies were performed at 1 month following anticoagulation therapy and the perfusion parameters thus obtained were compared with pre-treatment results. Receiver operating characteristic (ROC) curve analysis was performed to determine the prognostic significance of perfusion parameters. RESULTS: All patients in this study showed areas of hypoperfusion on CT perfusion. To determine the favorable clinical outcome on basis of perfusion parameters, ROC curve analysis was performed which showed that the optimal threshold for rCBF>60.5%, rCBV>75.5%, and rMTT<148.5% correlated with better clinical outcomes. Post treatment perfusion parameters showed significant correlation in core of the lesion (p<0.05) than in the periphery. CONCLUSION: CT perfusion studies in CVST are a good prognostic tool and yield valuable information regarding clinical outcome.

Relationship between acute kidney injury and brain MRI findings in asphyxiated newborns after therapeutic hypothermia.

BACKGROUND: We hypothesized that acute kidney injury (AKI) in asphyxiated neonates treated with therapeutic hypothermia would be associated with hypoxic-ischemic lesions on brain magnetic resonance imaging (MRI). METHODS: Medical records of 88 cooled neonates who had had brain MRI were reviewed. All neonates had serum creatinine assessed before the start of cooling; at 24, 48, and 72 h through cooling; and then on day 5 or 7 of life. A neonatal modification of the Kidney Disease: Improving Global Outcomes guidelines was used to classify AKI. MRI images were evaluated by a neuroradiologist masked to outcomes. Outcome of interest was abnormal brain MRI at 7-10 d of life. RESULTS: AKI was found in 34 (39%) of 88 neonates, with 15, 7, and 12 fulfilling criteria for stages 1, 2, and 3, respectively. Brain MRI abnormalities related to hypoxia-ischemia were present in 50 (59%) newborns. Abnormal MRI was more frequent in infants from the AKI group (AKI: 25 of 34, 73% vs. no AKI: 25 of 54, 46%; P = 0.012; odds ratio (OR) = 3.2; 95% confidence interval (CI) = 1.3-8.2). Multivariate analysis identified AKI (OR = 2.9; 95% CI = 1.1-7.6) to be independently associated with the primary outcome. CONCLUSION: AKI is independently associated with the presence of hypoxic-ischemic lesions on postcooling brain MRI.

Does clinical status 1 week after therapeutic hypothermia predict brain MRI abnormalities?

OBJECTIVE: Hypothermia improves clinical outcomes and brain magnetic resonance imaging (MRI) findings in infants with hypoxic-ischemic encephalopathy. We hypothesized that clinical status following hypothermia predicts brain MRI abnormalities, and helps determine which infants need an early MRI evaluation before discharge. The objective of this study was to determine whether the clinical evaluation 1 week after completion of 72 h of hypothermia treatment predicts the presence of brain MRI abnormalities related to hypoxia-ischemia. STUDY DESIGN: The medical records of 83 consecutively cooled infants who underwent brain MRI were reviewed. Clinical evaluation by day 10 of life consisted of assessment of oral feeding ability, spontaneous activity, need for mechanical ventilation and a history of clinical seizures. Logistic regression analysis was performed using all four covariates, with an abnormal MRI as the primary outcome. Brain MRI with lesions in both the basal nuclei and the cortex was considered to be severely abnormal. RESULT: MRI was abnormal in 46 (55%) infants. Univariate analysis identified all of the criteria as being significantly associated with an abnormal MRI. On multivariate analysis, only feeding difficulty (P<0.001, OR 9.5, 95% confidence interval (CI) 3 to 29.8) and a history of clinical seizures (P<0.001, OR 12, 95% CI 3 to 46.5) were significantly associated with an abnormal MRI. The areas under the receiver operating characteristic curve for feeding ability and seizure activity combined (0.86, 95% CI 0.77 to 0.94) indicated good accuracy with respect to the primary outcome. The negative predictive values of feeding difficulty and seizure activity for a severely abnormal MRI were 91% and 96%, respectively. CONCLUSION: Infants who do not have a history of clinical seizures and who attained full oral feeding by 1 week after hypothermia are unlikely to have an abnormal brain MRI. This simple assessment provides significant prognostic information that can be useful in parental counseling, and may allow selective use of pre-discharge MRI.

Improvement in Blood Supply After "Heparin-Dextran" Therapy in Patients of Buerger's Disease with Critical Limb Ischemia.

Alleviating the agonizing pain of critical limb ischemia (CLI) in patients of Buerger's disease (BD) has been challenging, due to lack of definitive treatment; "Heparin-Dextran" infusion has been tried in this study. Assessment of clinical improvement and vascular changes following therapy. Patients with CLI admitted to emergency surgical ward were studied prospectively. BD was diagnosed by Shionoya's criteria, and confirmed by digital subtraction angiography (DSA). Heparin and Dextran intravenous infusion was administered for 10 days. Severity of rest pain, ischemic changes in the feet, claudication distance and ankle brachial index (ABI) were estimated prior to therapy, at completion and 3 weeks after therapy. Vascular changes were assessed by CT angiography (CTA) performed prior to and 3 weeks after therapy. Twenty consecutive patients were studied. Successful hemodilution reflected by decreased hematocrit (37.4 % to 32.6 %, p < 0.05) and increased mean ABI (0.46 to 0.83, p < 0.01), improved rest pain in 75 % patients (p < 0.001), increased claudication distance in 94 % (p < 0.05) and ulcers healing in 70 % patients. CTA revealed recanalised vessels (decreased length of occluded segments) in 10 (50 %, p = 0.005), increased collaterals in 12 (60 %, p < 0.01) and improved distal run-off in 13 (65 %, p < 0.01) patients. "Heparin-Dextran" therapy in patients of CLI from BD improves tissue perfusion by increasing collaterals and recanalisation of vessels, resulting in significant relief from rest pain and clinical improvements. CTA is as efficacious as DSA for evaluation of BD.

Does phenobarbital improve the effectiveness of therapeutic hypothermia in infants with hypoxic-ischemic encephalopathy?

OBJECTIVE: To determine whether phenobarbital (PB) given before therapeutic hypothermia to infants with hypoxic-ischemic encephalopathy (HIE) augments the neuroprotective efficacy of hypothermia. STUDY DESIGN: Records of 68 asphyxiated infants of 36 weeks' gestation, who received hypothermia for moderate or severe HIE were reviewed. Some of these infants received PB prophylactically or for clinical seizures. All surviving infants had later brain magnetic resonance imaging (MRI). The composite primary outcome of neonatal death related to HIE with worsening multiorgan dysfunction despite maximal treatment, and the presence of post-hypothermia brain MRI abnormalities consistent with hypoxic-ischemic brain injury, were compared between the infants who received PB before initiation of hypothermia (PB group, n=36) and the infants who did not receive PB before or during hypothermia (No PB group, n=32). Forward logistic regression analysis determined which of the pre-hypothermia clinical and laboratory variables predict the primary outcome. RESULT: The two groups were similar for severity of asphyxia as assessed by Apgar scores, initial blood pH and base deficit, early neurologic examination, and presence of an intrapartum sentinel event. The composite primary outcome was more frequent in infants from the PB group (PB 78% versus No PB 44%, P=0.006, odds ratio 4.5, 95% confidence interval 1.6 to 12.8). Multivariate analysis identified only the PB receipt before initiation of hypothermia (P=0.002, odds ratio 9.5, 95% confidence interval 2.3 to 39.5), and placental abruption to be independently associated with a worse primary outcome. CONCLUSION: PB treatment before cooling did not improve the composite outcome of neonatal death or the presence of an abnormal post-hypothermia brain MRI, but the long-term outcomes have not yet been evaluated.

Adenosine-induced cardiac standstill to facilitate endovascular embolisation of cerebral arteriovenous malformations in children.

This report describes three children, aged eight to 11 years, with high-flow cerebral arteriovenous malformations who underwent interventional neuroradiological procedures involving glue (N-butyl cyanoacrylate) embolisation under general anaesthesia. The procedure was facilitated by relative hypotension induced by esmolol infusion and intravenous adenosine boluses. To allow controlled deposition of N-butyl cyanoacrylate into the arteriovenous malformations, glue injection was synchronised with the onset of adenosine-induced brief cardiac standstill. This resulted in satisfactory obliteration of the arteriovenous malformations nidus in all cases. The haemodynamic modulations, including the adenosine-induced brief cardiac standstill, was noted to not affect the BIS values in our patients. All patients had satisfactory obliteration of their arteriovenous malformations and had good neurological outcomes at one-year follow-up.

Is there a role for virtual otoscopy in the preoperative assessment of the ossicular chain in chronic suppurative otitis media? Comparison of HRCT and virtual otoscopy with surgical findings.

The aim of this study was to assess the role of virtual otoscopy and 3D ossicular reconstruction in the preoperative assessment of the ossicles in chronic suppurative otitis media. Thirty three patients of chronic suppurative otitis media with conductive deafness (air-bone gap > 35 dB) were included in this prospective study. All patients underwent axial multidetector CT. The axial CT data set was utilized for multiplanar 2D reformations as well as virtual otoscopy (VO) and 3D reconstructions. The imaging findings on these two techniques were read independently by two radiologists with respect to different parts of the ossicular chain by using a three-point scoring system and were compared with surgical findings. Both imaging techniques had comparable accuracy for evaluation of larger ossicular parts. However, for evaluation of stapes superstructure, VO/3D images were more accurate (85.29%) than 2D images (76.97%). Assessment of the lenticular process and incudostapedial joint by HRCT and 2D reformatted images was not reliable (P > 0.1); however, significant correlation (P < 0.001) was present between VO/3D and the operative findings. Virtual otoscopy improves evaluation of the ossicular chain particularly that of smaller structures such as the lenticular process, incudostapedial joint and stapes superstructure which may influence decisions regarding planning of ossiculoplasty.

Postpyelolithotomy renal artery pseudoaneurysm management with percutaneous thrombin injection: a case report.

Renal artery pseudoaneurysm leading to life-threatening hematuria can occur after a surgical procedure such as pyelolithotomy, albeit rarely. With recent advances in transarterial embolization techniques, this minimally invasive procedure has become the treatment of choice, replacing surgery. We present a case of massive hematuria due to renal artery pseudoaneurysm developing after pyelolithotomy that was managed with percutaneus thrombin injection directly into the pseudoaneurysm.

Basilar artery aneurysm treated with coil embolization via persistent primitive hypoglossal artery.

A saccular aneurysm at the basilar artery bifurcation associated with a persistent primitive hypoglossal artery (PPHA) was successfully treated by endovascular occlusion with Guglielmi detachable coils. As both vertebral arteries were aplasitc, a microcatheter was advanced via PPHA. To the best of our knowledge, this is the first case report describing the treatment of a basilar top aneurysm through the PPHA.

Excision of pituitary adenomas: randomized comparison of surgical modalities.

The aim of this randomized prospective study was to compare the efficacy of endoscopic versus standard microsurgical excision of pituitary adenomas, and to evaluate the merits and demerits of each approach. Twenty patients with a pituitary adenoma were randomly divided into two groups comprising of 10 cases each. Ten cases were operated by endoscopic endonasal trans-sphenoidal approach by endoscopic rhinologist (EETSS group) and other 10 cases were excised by microsurgical endonasal trans-sphenoidal approach by a neurosurgeon (SMETSS group). In both the groups complete excision was achieved in 50% of patients (unpaired t-test, p = 1.00). In EETSS group mean operative time was 64.5 +/- 19.16 min (range 50 - 100 min). In the SMETSS group, mean operative time was 75.5 +/- 18.48 min (range 55 - 120 min; unpaired t-test, p = 0.64, statistically not significant). In the EETSS group blood loss ranged between 100 and 190 ml (mean 100 +/- 42.16 ml). In the SMETSS group blood loss ranged between 50 and 250 ml (mean loss of 120 +/- 58.69 ml; unpaired t-test, p < 0.05, statistically significant). Postoperative nasoseptal complications were more common in SMETSS group (Chi-square test, p < 0.05, statistically significant). Endoscopic approach provides a wide surgical field and broad lateral vision making easier distinction of tumour tissue: gland and gland diaphragm interface. Thus, there is less blood loss and nasoseptal complications, whereas there was no statistically significant difference in operative time and complete tumour removal.

Comparison of CT venography with MR venography in cerebral sinovenous thrombosis.

OBJECTIVE: The purpose of this study was to compare cerebral CT venography with MR venography and determine the reliability of CT venography in the diagnosis of cerebral sinovenous thrombosis. SUBJECTS AND METHODS: Fifty patients who were clinically suspected of having cerebral sinovenous thrombosis, irrespective of age and sex, underwent cerebral CT venography and MR venography. Projection venograms were displayed using maximum-intensity-projection images for both CT venography and MR venography. The CT venograms were also displayed using the integral algorithm, which depicts the average intensity value of the first five voxels deep in relation to the model surface that is nearest the viewer, allowing direct visualization of the thrombus in the sinuses. All CT venograms and MR venograms were independently evaluated by experienced neuroradiologists. RESULTS: Of these 50 patients, 30 patients were diagnosed as having cerebral sinovenous thrombosis on both CT venography and MR venography. The total numbers of sinuses involved were 81 and 77 (CT venography and MR venography). When MR venography was used as the gold standard, CT venography was found to have both a sensitivity and a specificity of 75-100%, depending on the sinus and vein involved. CONCLUSION: CT venography is as accurate as MR venography for diagnosing cerebral sinovenous thrombosis.

Liver abscess associated with hepatic artery pseudoaneurysm with arteriovenous fistula: imaging and interventional management.

Hepatic artery pseudoaneurysm is an infrequently encountered entity that is usually seen secondary to trauma or surgical procedures. The clinical presentation is often due to complications such as massive intrahepatic or intraperitoneal bleeding as a result of rupture of the pseudoaneurysm into the biliary tree or peritoneal cavity, respectively. Hepatic artery pseudoaneurysm, associated with a liver abscess, has very rarely been described in the literature. We present the imaging features of a case of liver abscess associated with a hepatic artery pseudoaneurysm and complicated by rupture and formation of an arteriovenous fistula. The case was successfully managed by percutaneous endovascular embolization. The association between a hepatic artery pseudoaneurysm and a liver abscess must not be overlooked, bearing in mind the potentially fatal associated complications which can be averted or treated by timely intervention.

Preoperative embolization of a large vaginal leiomyoma: report of a case and review of the literature.

Leiomyoma of the vagina is a very rare tumour of the lower urogenital tract. These slow-growing masses may be asymptomatic or present with pain, dyspareunia or urinary symptoms. Rarely, these tumours may present with life-threatening haemorrhage. These hypervascular tumours are treated by surgical excision. Preoperative embolization therefore may aid in devascularization of these tumours before surgical excision. We present the MRI features of a case of vaginal leiomyoma, which was managed by preoperative embolization and was then excised in toto. To the best of our knowledge, this is the first report where preoperative embolization was performed before excision of a vaginal leiomyoma with minimal peroperative blood loss.

Transcatheter embolization of internal pudendal artery pseudoaneurysm following traumatic urethral catheterization.

Urethral catheterization is a routine procedure. We report an unusual complication due to a traumatic urethral catheterization. The resulting pseudoaneurysm of the bulbar artery required selective embolization of the internal pudendal artery.