Diffusion-weighted MR imaging of pyogenic ventriculitis

From images to insights: a neuroradiologist's practical guide on white matter fiber tract anatomy and DTI patterns for pre-surgical planning

INTRODUCTION

Diffusion tensor imaging (DTI) is a valuable non-invasive imaging modality for mapping white matter tracts and assessing microstructural integrity, and can be used as a "biomarker" in diagnosis, differentiation, and therapeutic monitoring. Although it has gained clinical importance as a marker of neuropathology, limitations in its interpretation underscore the need for caution.

METHODS

This review provides an overview of the principles and clinical applicability of DTI. We focus on major white matter fiber bundles, detailing their normal anatomy and pathological DTI patterns, with emphasis on tracts routinely requested in our neurosurgical department in the preoperative context (uncinate fasciculus, arcuate fasciculus, pyramidal pathway, optic radiation, and dentatorubrothalamic tract).

RESULTS

We guide neuroradiologists and neurosurgeons in defining volumes of interest for mapping individual tracts and demonstrating their 3D reconstructions. The intricate trajectories of white matter tracts pose a challenge for accurate fiber orientation recording, with each bundle exhibiting specific characteristics. Tracts adjacent to brain lesions are categorized as displaced, edematous, infiltrated, or disrupted, illustrated with clinical cases of brain neoplasms. To improve structured reporting, we propose a checklist of topics for inclusion in imaging evaluations and MRI reports.

CONCLUSION

DTI is emerging as a powerful tool for assessing microstructural changes in brain disorders, despite some challenges in standardization and interpretation. This review serves an educational purpose by providing guidance for fiber monitoring and interpretation of pathological patterns observed in clinical cases, highlighting the importance and potential pitfalls of DTI in neuroradiology and surgical planning.

Neuroimaging Patterns of Intracranial Infections: Meningitis, Cerebritis, and Their Complications

Neuroimaging provides rapid, noninvasive visualization of central nervous system infections for optimal diagnosis and management. Generalizable and characteristic imaging patterns help radiologists distinguish different types of intracranial infections including meningitis and cerebritis from a variety of bacterial, viral, fungal, and/or parasitic causes. Here, we describe key radiologic patterns of meningeal enhancement and diffusion restriction through profiles of meningitis, cerebritis, abscess, and ventriculitis. We discuss various imaging modalities and recent diagnostic advances such as deep learning through a survey of intracranial pathogens and their radiographic findings. Moreover, we explore critical complications and differential diagnoses of intracranial infections.

Ventriculitis: A Severe Complication of Central Nervous System Infections

BACKGROUND

Ventriculitis, a dreaded complication of brain abscess, meningitis, and various neurosurgical procedures, has attracted limited attention in the medical literature.

METHODS

This is a retrospective, single-center study. We screened the medical files of all patients who had a brain imaging report that included the word "ventriculitis" during years 2005-2019. Only patients with clinical, microbiological, and imaging features of ventriculitis were included. Data were collected through a standardized questionnaire.

RESULTS

Ninety-eight patients fulfilled inclusion criteria: 42 women and 56 men, and the median age was 60 years (interquartile range, 48-68). The primary mechanism for ventriculitis was classified as follows: brain abscess (n = 29, 29.6%), meningitis (n = 27, 27.6%), intraventricular catheter-related (n = 17, 17.3%), post-neurosurgery (n = 13, 13.3%), and hematogenous (n = 12, 12.2%). The main neuroimaging features were intraventricular pus (n = 81, 82.7%), ependymal enhancement (n = 70, 71.4%), and intraventricular loculations (n = 15, 15.3%). The main pathogens were streptococci (n = 44, 44.9%), Gram-negative bacilli (n = 27, 27.6%), and staphylococci (n = 15, 15.3%). In-hospital and 1-year mortality rates were 30.6% (n = 30) and 38.8% (n = 38), respectively. Neurological sequelae were reported in 34 of 55 (61.8%) survivors, including cognitive impairment (n = 11), gait disturbances (n = 9), paresis (n = 7), behavior disorder (n = 6), and epilepsy (n = 5). On multivariate analysis, age >65 years, Glasgow Coma Scale score <13 at initial presentation, status epilepticus, hydrocephalus, and positive cerebrospinal fluid culture were associated with 1-year mortality. We built a scoring system to stratify patients with ventriculitis into low risk (12.5%), intermediate risk (36.5%), and high risk (71.4%) of death.

CONCLUSIONS

Ventriculitis is a severe complication of brain abscess, meningitis, or neurosurgery, with an in-hospital mortality rate of 30% and neurological sequelae in 60% of survivors.

Dental focal infection-induced ventricular and spinal canal empyema: A case report

BACKGROUND

Dental focal infection-induced ventricular and spinal canal empyema is an extremely rare, severe, acute disease that is clinically associated with extremely high morbidity and mortality. Traditional cerebrospinal fluid (CSF) bacterial culture is time-consuming, with a low positive rate, which frequently results in severe irreversible consequences. The next-generation sequencing technique is an emerging pathogenic microorganism detection method that can obtain results in a short time with high accuracy, thus providing great assistance in the clinical diagnosis and treatment of this disease.

CASE SUMMARY

This paper reports a rare case of dental focal infection-induced ventricular and spinal canal empyema. During the course of treatment at a local hospital, the patient had negative results from repeated CSF bacterial cultures and was empirically given vancomycin treatment. After transfer to our hospital, the next-generation sequencing technique was adopted to determine that the pathogenic microorganisms were multiple anaerobic infectious bacteria derived from the oral cavity. The antibiotic therapeutic scheme was adjusted in a timely manner, and the ventricular and spinal canal inflammation was also controlled. However, the antibiotics that had been applied at the local hospital were not able to cover all pathogenic microorganisms, which resulted in irreversible injury to the brain stem, finally leading to patient death.

CONCLUSION

Dental focal infection-induced ventricular and spinal canal empyema is an extremely rare, severe, acute disease with high morbidity and mortality. Any delay in diagnosis and treatment will result in irreversible consequences. The early application of the next-generation sequencing technique can obtain results in a short time and clarify a diagnosis. Appropriate antibiotic treatment combined with suitable surgical intervention is the key to managing this disease.

Use of computed tomography and diffusion weighted imaging in children with ventricular shunt

PURPOSE

To evaluate the indications, number, and imaging results of brain computed tomography (CT) and diffusion weighted imaging (DWI) in children with ventriculoperitoneal shunt, to estimate the radiation dose, and to evaluate the effectiveness of DWI.

METHODS

This retrospectively study included 54 consecutive patients (boys/girls = 30/24, mean age, 3 ± 4.1 years) with shunt that were placed due to congenital abnormalities-hypoxic ischemic encephalopathy between January 2015 and March 2018. The presence of shunt-related complications (SRC) was assessed using clinical and neuroimaging findings, and the standard reference was accepted as the shunt revision. Size comparisons of ventricles were performed using Evans index and the frontal and occipital horn ratio, and each measurement made by the observers were compared using Bland-Altman analysis. A kappa coefficient and the intraclass correlation coefficient were calculated to assess the agreement between observers.

RESULTS

The mean number of hospital admission, number of CT scans, and DWI were 5.8, 4.8, and 1.1, respectively per patient. A significant linear correlation was observed between hospital admission and CT scans (r = 0.288, p = 0.035). The number of CT scans and the cumulative effective dose per patient were higher in patients with SRC than in those without (p < 0.001). The mortality rate due to radiation-induced neoplasia has increased by 0.33% in the study period. The inter-observer agreement was perfect or substantial for the catheter visualization, assessment of the ventricular system on DWI, and for the image quality of DWI between observers (κ = 0.704-1, p ≤ 0.001). No significant difference was found between CT and DWI in the measurements of Evans index and the frontal and occipital horn ratio (p > 0.05). Inter-observer agreements between observers were almost perfect for the Evans index and the frontal and occipital horn ratio (ICC = 0.94-0.99, p < 0.001).

CONCLUSIONS

An awareness of the use of CT in children is still inadequate and difficulties in the diagnosis of SRC probably cause the overuse of CT. DWI should be preferred in the diagnosis of SRC and the follow-up of patients. Otherwise, the increase in the prevalence of several diseases, particularly neoplasia, may be inevitable because of the over use of CT.

Pyogenic brain abscess, ventriculitis and diffuse meningitis with fatal outcome in an adult: Radiologic-pathologic correlation☆,

Rupture of brain abscesses with evolution into ventriculitis with meningitis may result in sudden and dramatic worsening of the clinical situation. We present a 57-year-old man with such an event and fatal outcome. Multiple imaging modalities including computed tomography and advanced magnetic resonance imaging were correlated with gross specimen and histologic images. The differential diagnosis of multiple lesions with ring enhancement and prominent perifocal edema includes mainly infectious and neoplastic processes, such as brain abscess, metastasis, and multicentric glioblastoma. Pyogenic ventriculitis is an uncommon manifestation of severe intracranial infection that might be clinically obscure. We discuss the characteristic magnetic resonance findings of brain abscess and its complications, including meningitis and ventriculitis with emphasis on the role of diffusion-weighted and fluid-attenuated inversion recovery imaging.

Pyogenic Ventriculitis and Meningitis Caused by Streptococcus Acidominimus in Humans: A Case Report

Patient: Male, 49

Final Diagnosis: Pyogenic ventriculitis and meningitis caused by Streptococcus acidominimus

Symptoms: Confusion • fever • headache

Medication: —

Clinical Procedure: Antibiotics

Specialty: Infectious Diseases

Diffusion-weighted MRI abnormalities in an outbreak of Streptococcus agalactiae Serotype III, multilocus sequence type 283 meningitis

PURPOSE

In 2015, an outbreak of group B streptococcal (GBS) infection caused by Streptococcus agalactiae Serotype III, multilocus sequence type 283, related to consuming infected raw freshwater fish, affected more than 200 patients in Singapore. We describe the clinical, laboratory, and neuroimaging features of a subgroup of adults with central nervous system (CNS) infections caused by GBS.

MATERIALS AND METHODS

The database of the Singapore Neurologic Infections Program (SNIP), a national multicenter study for surveillance of infectious neurologic disease, was reviewed to select patients with GBS CNS infection during the outbreak. Cases were diagnosed on the basis of clinical features, cerebrospinal fluid (CSF) findings and identification or isolation of Streptococcus agalactiae in the blood or CSF. Demographic, clinical and neuroradiological information was obtained prospectively and retrospectively abstracted.

RESULTS

Fourteen patients (6 male, 8 female; median age, 58 years) presented with fever, meningism, headache, encephalopathy, focal neurological deficits, and/or seizures. All except two were previously healthy. Diffusion-weighted imaging (DWI) on admission was abnormal in 13 patients, showing tiny hyperintensities in the subarachnoid space (7 patients), ventricles (6 patients) and brain parenchyma (8 patients); 5 patients had cerebellar abnormalities.

CONCLUSION

Among healthy non-pregnant adults infected with Serotype III, multilocus sequence type 283 GBS meningitis linked to eating infected raw freshwater fish, DWI detected small pus collections and unusual cerebellar involvement. A collaborative national surveillance system that includes MRI can be helpful during unusual food-borne zoonotic infectious disease outbreaks.

LEVEL OF EVIDENCE

4 J. Magn. Reson. Imaging 2017;45:507-514.

A case of meningococcal meningitis that was difficult to treat owing to concurrent ventriculitis

A 64-year-old male came to our hospital emergency department with fever and consciousness disturbance. Culture tests of blood and spinal fluid samples revealed meningococci (Neisseria meningitidis), and we made a diagnosis of meningococcal meningitis. Brain magnetic resonance imaging (MRI) findings revealed ventriculitis. Ceftriaxone was administered for 17 days, however, relapse was noted after that was discontinued, with neutropenia and renal impairment thought to be adverse reactions to the beta-lactam antibiotic. Hence, treatment was switched to oral administration of moxifloxacin for a total of 12 weeks, including in an outpatient setting. After moxifloxacin was discontinued, no side effects or relapse were seen, and treatment was ended. Although antibacterial agents generally show favorable effects for meningococcal meningitis, we consider that sufficient antimicrobial therapy is difficult in cases complicated with ventriculitis.

A Rare Cause of Calcified Subdural Empyema and Ventriculitis in a Pediatric Patient: Achromobacter Denitrificans

Intracranial infections in the pediatric age group are still important causes of morbidity in developing countries. A 2-year-old male patient presented with acute onset of seizures and loss of consciousness to our emergency department with a past history of being followed for hypogammaglobulinemia. Unenhanced computerized tomography scan of the brain revealed a right frontoparietal peripherally calcified extraaxial collection, brain edema and a left sided shift. Contrast enhanced magnetic resonance imaging revealed a subdural empyema associated with the brain parenchyma and the ventricular system. In spite of a decompression procedure and subsequent medical therapy, the patient succumbed on the 9. postoperative day. This is the first case report of a pediatric patient with subdural empyema and ventriculitis due to Achromobacter denitrificans.

Magnetic Resonance Imaging of Pediatric Neurologic Emergencies

Although computed tomography is often the first line of imaging in the emergency setting, magnetic resonance imaging (MRI) is of increasing importance in the evaluation of central nervous system emergencies in the pediatric population. As such, it is necessary to understand the indications for which MRI may be necessary. This article reviews the unique pathophysiologic entities affecting the pediatric population and the associated MRI findings. Specifically, utility of emergent MRI and characteristic appearances of traumatic brain injury, traumatic spinal injury, nonaccidental trauma, arterial ischemic stroke, cerebral sinovenous thrombosis, stroke mimics, and central nervous system infections are described.

Magnetic resonance imaging of infectious meningitis and ventriculitis in adults

Magnetic resonance imaging findings of meningitis are usually nonspecific with respect to the causative pathogen because the brain response to these insults is similar in most cases. In this article, we will use a few representative cases to describe the characteristic magnetic resonance findings of meningitis and its complications, including ventriculitis.

[Pathognomonic magnetic resonance imaging (MRI) finding of fluid-fluid level in pyogenic ventriculitis: two case reports]

Pyogenic ventriculitis is an uncommon and potentially fatal central nervous system infection. Delayed treatment due to non specific clinical symptoms may lead to an unfavorable outcome. Brain magnetic resonance imaging (MRI) plays an important role in the diagnosis of pyogenic ventriculitis. We describe two patients with pyogenic ventriculitis presenting with a pathognomonic MRI finding. The first patient, a 77-year-old female, developed high fever and consciousness disturbance. MR images revealed hyperintense lesions with a fluid-fluid level in the bilateral lateral ventricles on diffusion-weighted images (DWIs) and hypointense lesions on T2-weighted images (T2WIs). MR images also revealed findings of left otitis media. The second patient, a 63-year-old male, who had a past history of multiple myeloma and had received chemotherapy, developed high fever and left hemiparesis. MR images revealed a hyperintense lesion with a fluid-fluid level in the right lateral ventricle on DWIs and a hypointense lesion on T2WIs, multiple ring-enhancing lesions on gadolinium enhanced T1-weighted images, and pontine infarction on DWIs. Chest computed tomography revealed an infiltrative shadow in the lower lobe of the left lung. On the basis of MRI findings, both patients were diagnosed as having pyogenic ventriculitis and were administered high-dose meropenem intravenously. The second patient was also administered sulfamethoxazole-trimethoprim orally. Intraventricular abnormalities disappeared and the patients achieved complete remission after the antibacterial treatment. Intraventricular hyperintense lesions on DWIs and hypointense ones on T2WIs with a fluid-fluid level is a pathognomonic finding of pyogenic ventriculitis and has not been previously reported in other diseases. Recognition of the characteristic MRI features and initiation of high-dose and appropriate antibiotics in an early stage may lead to a favorable outcome of the disease.

Diffusion magnetic resonance imaging diagnostic relevance in pyogenic ventriculitis with an atypical presentation: a case report

BACKGROUND

Pyogenic ventriculitis is a rare and severe cerebral infection characterized by the presence of suppurative fluid in the cerebral ventricles. It is a life-threatening condition and may present with an aspecific neurological picture. Brain imaging techniques usually demonstrate intraventricular debris and pus, but negative imaging along with a misleading clinical picture may delay the diagnosis.

CASE PRESENTATION

The described patient underwent a number of surgical procedures and eventually developed an unusual clinical picture characterized by psychomotor slowing, facial dyskinesias and myoclonic jerks without complaint of headache and in absence of meningeal irritation signs or focal neurological deficits. Cerebrospinal fluid cultural examination showed methicillin-resistant Staphylococcus aureus and vancomycin treatment lead to a complete recovery. Brain computed tomography scan was normal, while only diffusion magnetic resonance imaging sequences were able to define the presence of purulent material within the brain lateral ventriculi.

CONCLUSION

The present case underlines the importance of taking into account the diagnosis of pyogenic ventriculitis even when the neurological picture does not match the suspect of a central nervous system infection. Moreover, brain computed tomography scan and standard magnetic resonance imaging sequences may be unable to confirm the diagnosis, whereas diffusion-weighted sequences prove a unique role in diagnosing cerebral pyogenic ventriculitis.

Clinico-radiological features of subarachnoid hyperintensity on diffusion-weighted images in patients with meningitis

AIM

To investigate the clinical and radiological features of meningitis with subarachnoid diffusion-weighted imaging (DWI) hyperintensity.

MATERIALS AND METHODS

The clinical features, laboratory data, and radiological findings, including the number and distribution of subarachnoid DWI hyperintense lesions and other radiological abnormalities, of 18 patients seen at five institutions were evaluated.

RESULTS

The patients consisted of eight males and 10 females, whose ages ranged from 4 months to 82 years (median 65 years). Causative organisms were bacteria in 15 patients, including Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus agalactiae, Staphylococcus aureus, Klebsiella pneumoniae, and Listeria monocytogenes. The remaining three were fungal meningitis caused by Cryptococcus neoformans. Subarachnoid DWI hyperintense lesions were multiple in 16 of the 18 cases (89%) and predominantly distributed around the frontal lobe in 16 of the 18 cases (89%). In addition to subarachnoid abnormality, subdural empyema, cerebral infarction, and intraventricular empyema were found in 50, 39, and 39%, respectively. Compared with paediatric patients, adult patients with bacterial meningitis tended to have poor prognoses (7/10 versus 1/5; p = 0.1).

CONCLUSION

Both bacterial and fungal meningitis could cause subarachnoid hyperintensity on DWI, predominantly around the frontal lobe. This finding is often associated with poor prognosis in adult bacterial meningitis.

Imaging diagnosis--Ventriculo-peritoneal shunt associated infection in a dog

Ventriculo-peritoneal shunting is a surgical treatment for hydrocephalus. Complications of this procedure are not well described in dogs. The most common complication in humans is infection, which can be fatal if not diagnosed and treated quickly. We describe the magnetic resonance (MR) imaging characteristics of a shunt-associated cerebral infection in a dog. The MR features of the infection included hyperintensity of the lining of the ventricular system visible on a T2-weighted FLAIR sequence and marked linear contrast enhancement of the ependymal layer on T1-weighted sequences, similar to that described in people.

Diffusion MR imaging for monitoring treatment response

The objective of this article was to emphasize the use of diffusion-weighted imaging in the diagnosis and follow-up of several major disease contexts, as established in recent literature. In some of these diseases the diffusion changes are correlated with the clinical deficit and are potentially useful for early diagnosis and longitudinal evaluation, as well as in the context of pharmacologic trials. Diffusion magnetic resonance is a major advance in the continuing evolution of MR imaging. It provides contrasts and characterization between tissues at a cellular level that may imply differences in function as well as framework and have contributed to a better understanding of the pathophysiological mechanisms of several diseases.

Diffusion imaging in brain infections

Diffusion-weighted magnetic resonance imaging (DWI) provides image contrasts that are different from conventional magnetic resonance techniques. DWI is particularly sensitive for detecting acute ischemic stroke, but it also has many other clinical applications, including the evaluation of central nervous system (CNS) infections. This article addresses the role of DWI in the differential diagnosis of CNS infections, and discusses the most common DWI findings for each type of infection.

Imaging findings in pyogenic ventriculitis

INTRODUCTION

Pyogenic ventriculitis is an uncommon but often severe intracranial infection.

METHODS

Case report with illustrative CT and MRI imaging.

RESULTS

A 49-year-old man presented with an intraparenchymal hematoma with extension of blood into the ventricles. The persistence of intraventricular blood necessitated long term placement of an external ventricular drain. On day 23 after admission, a contrast-enhanced CT scan of the brain showed slight hydrocephalus, irregular debris in the dependent part of the occipital horns and periventricular hypodensities. An MRI scan confirmed the characteristic hallmarks of pyogenic ventriculitis on the T2-weighted, Fluid Attenuated Inversion Recovery (FLAIR), and diffusion-weighted and contrast-enhanced T1-weighted images.

CONCLUSION

Neuroimaging is crucial in clearly depicting pyogenic ventriculitis. A contrast-enhanced CT scan, but especially MR imaging, is an ideal tool to reliably diagnose this life-threatening cerebral infection.

Diffusion tensor MR imaging and fiber tractography: theoretic underpinnings

In this article, the underlying theory of clinical diffusion MR imaging, including diffusion tensor imaging (DTI) and fiber tractography, is reviewed. First, a brief explanation of the basic physics of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping is provided. This is followed by an overview of the additional information that can be derived from the diffusion tensor, including diffusion anisotropy, color-encoded fiber orientation maps, and 3D fiber tractography. This article provides the requisite background for the second article in this 2-part review to appear next month, which covers the major technical factors that affect image quality in diffusion MR imaging, including the acquisition sequence, magnet field strength, gradient amplitude and slew rate, and multichannel radio-frequency coils and parallel imaging. The emphasis is on optimizing these factors for state-of-the-art DWI and DTI based on the best available evidence in the literature.

Retroperitoneal infection complicated by bacterial meningitis and ventriculitis with secondary brainstem infarction

INTRODUCTION

Retroperitoneal abscesses have been previously reported to cause infectious meningitis. Cerebral infarction is a known complication of basilar meningitis.

SUMMARY OF CASE

We present a case where a comatose patient with a known retroperitoneal abscess was diagnosed via Magnetic Resonance Imaging (MRI) with extensive brainstem infarction secondary to basilar meningitis.

Diffusion-weighted MR imaging of pyogenic intraventricular empyema

INTRODUCTION

Pyogenic intraventricular empyema (PIE) is a potentially fatal CNS infection. However, it is sometimes difficult to diagnose PIE on the basis of clinical and conventional MRI findings. Diffusion-weighted imaging (DWI) has been accepted as a useful MR sequence for the diagnosis of various intracranial infections. The purpose of this study was to determine the DWI characteristics of PIE and the role of DWI in the diagnosis of PIE.

METHODS

Eight patients with PIE underwent MRI including DWI. We assessed the presence and signal characteristics of PIE. In seven patients, the signal intensities of the PIE and cerebrospinal fluid (CSF) were measured and the contrast-to-noise ratio (CNR) percentage was calculated. ADC values of the PIE, CSF, and white matter were also determined.

RESULTS

PIE was detected in all patients by DWI, in five (63%) by FLAIR imaging, and in two (25%) by T1- and T2-weighted imaging. The CNR percentages of the PIEs in relation to the CSF were highest for DWI, followed by FLAIR, T1-, and T2-weighted imaging. There were statistically significant differences between the images of each sequence. In all patients, PIE showed hyperintensities on DWI and hypointensities to the CSF and hypo- or isointensities to the white matter on ADC maps. The ADC values (mean+/-SD) of the PIE, CSF, and white matter were 0.60+/-0.27, 2.81+/-0.04, and 0.79+/-0.08 (x10(-3) mm(2)/s). There was a statistically significant difference between PIE and the CSF.

CONCLUSION

PIE shows a bright intensity on DWI, and DWI is a sensitive MR sequence for the diagnosis of PIE.

Comparison of MRI sequences to detect ventriculitis

OBJECTIVE

The ability of different MRI sequences to depict characteristic findings suggestive of ventriculitis was compared.

CONCLUSION

The study comprised 20 brain MRI studies in 13 patients who had a final diagnosis of ventriculitis. Both diffusion-weighted imaging and FLAIR imaging were equally and highly sensitive for detecting intraventricular debris and pus--the most common MRI finding suggestive of ventriculitis. FLAIR imaging was superior to contrast-enhanced T1-weighted imaging for depicting ventricular wall abnormalities--a less common finding that also is suggestive of ventriculitis.

[Multislice CT urography Aspects for technical management and clinical application]

The introduction of multislice computed tomography with its well-known advantages has made it possible to visualize the entire urinary tract with thin collimation during a breath-holding phase. CT data acquisition during urographic contrast enhancement for contiguous imaging of the entire upper urinary tract is termed "multislice CT urography" (MSCTU). Multiplanar reconstructions, maximum intensity projections, and average intensity projections can be rendered from the volume datasets to view the urogenital tract. MSCTU will play an important role in the future of modern uroradiology. This article describes the technical aspects involved in the course of the MSCTU examination and identifies additional potential indications for clinical application.

Serial diffusion-weighted MRI correlates with clinical course and treatment response in children with intracranial pus collections

BACKGROUND

Accurate assessment of treatment response in children with intracranial pus collections is vital to guide appropriate therapy and reduce morbidity and mortality.

OBJECTIVE

To correlate serial MR-measurable changes in diffusion-weighted imaging (DWI) with clinical response to treatment.

MATERIALS AND METHODS

We retrospectively reviewed clinical notes, conventional MR sequences and DWI in eight children with intracranial pus collections. Trace DWI signal intensity and apparent diffusion coefficient (ADC) values were compared at three time points: at initial diagnosis (eight children, 13 collections), at follow-up during continued clinical infection (three children, sp collections), and at follow-up when clinical infection had resolved (seven children, 12 collections).

RESULTS

At initial diagnosis all patients were septic and collections showed restricted diffusion (mean ADC 0.61+/-0.15 x 10(-3) mm(2)/s). Patients with persistent clinical sepsis at follow-up DWI had collections with persistent low ADC values (0.66+/-0.21 x 10(-3) mm(2)/s), significantly (P<0.001) below normal cortical gray matter values. Successful resolution of the infection was associated with a significant rise in ADC values (1.57+/-0.57 x 10(-3) mm(2)/s, P<0.01) compared both to patients with signs of continued sepsis and to normal gray matter values.

CONCLUSION

Persistent restricted diffusion in pus collections correlates with continued sepsis. Treatment response is associated with clinical resolution of sepsis and ADC value elevation significantly above normal gray matter values.

Multi-detector row CT urography in the evaluation of hematuria

Hematuria can be well evaluated with a comprehensive contrast material-enhanced multi-detector row computed tomography (CT) protocol that combines unenhanced, nephrographic-phase, and excretory-phase imaging. Unenhanced images are obtained from the kidneys to the bladder and allow optimal detection of renal calculi, a common cause of hematuria. Renal parenchymal abnormalities, particularly masses, are best visualized on nephrographic-phase images, which also provide excellent evaluation of the other abdominal organs. Thin-section delayed images obtained from the kidneys to the bladder demonstrate the urinary tract distended with contrast material and are useful in detecting urothelial disease. Intravenous urography, ultrasonography, CT, retrograde ureterography and pyelography, cystoscopy, and ureteroscopy can all be used to evaluate patients with hematuria. In the past, a combination of several of these examinations was necessary to fully evaluate these patients. Now, however, this CT protocol may permit evaluation of hematuria patients with a single comprehensive examination, although more experience and data are needed to determine its efficacy in this setting.