Prenatal MR Imaging Phenotype of Fetuses with Tuberous Sclerosis: An Institutional Case Series and Literature Review.

BACKGROUND AND PURPOSE: Most patients with tuberous sclerosis complex (TSC) do not receive prenatal diagnosis. Our aim was to describe MR imaging findings to determine the following: 1. Whether normal fetal MR imaging is more common in fetuses imaged at ≤24 weeks' gestation compared with >24 weeks 2. The frequency of cardiac rhabdomyoma 3. The range of MR imaging phenotypes in fetal tuberous sclerosis complex. MATERIALS AND METHODS: Our institutional fetal MR imaging data base was searched between January 1, 2011 and June 30, 2021, for cases of TSC confirmed either by genetic testing, postnatal imaging, postmortem examination, or composite prenatal imaging findings and family history. A MEDLINE search was performed on June 8, 2021. RESULTS: Forty-seven published cases and 4 of our own cases were identified. Normal findings on fetal MR imaging were seen at a lower gestational age (mean, 24.7 [SD, 4.5 ] weeks) than abnormal findings on MR imaging (mean, 30.0 [SD, 5.3] weeks) (P = .008). Nine of 42 patients with abnormal MR imaging findings were ≤24 weeks' gestation. Subependymal nodules were present in 26/45 cases (57.8%), and cortical/subcortical lesions, in 17/46 (37.0%). A foramen of Monro nodule was present in 15 cases; in 2/7 cases in which this was unilateral, it was the only abnormal cerebral finding. Cardiac rhabdomyoma was absent in 3/48 cases at the time of fetal MR imaging but was discovered later. Megalencephaly or hemimegalencephaly was observed in 3 cases. CONCLUSIONS: Fetuses with abnormal cranial MR imaging findings were older than those with negative findings. Fetal hemimegalencephaly and megalencephaly should prompt fetal echocardiography. Cardiac rhabdomyoma was not always present at the time of fetal MR imaging.

The Fetus with Ganglionic Eminence Abnormality: Head Size and Extracranial Sonographic Findings Predict Genetic Diagnoses and Postnatal Outcomes.

BACKGROUND AND PURPOSE: Ganglionic eminence abnormalities on fetal MR imaging are associated with cerebral malformations. Their presumed genetic basis and associated postnatal outcomes remain largely unknown. We aimed to elucidate these through a multicenter study. MATERIALS AND METHODS: Between January 2010 and June 2020, seven hospitals in 2 countries performing fetal MR imaging examinations identified fetal MR imaging studies demonstrating ganglionic eminence enlargement, cavitation, or both. Cases with no genetic diagnosis, no whole exome sequencing, or no outcome of a liveborn child were excluded. Head size was classified as large (fronto-occipital diameter > 95th centile), small (fronto-occipital diameter <5th centile), or normal. RESULTS: Twenty-two fetuses with ganglionic eminence abnormalities were identified. Of 8 with large heads, 2 were diagnosed with MTOR mutations; 1 with PIK3CA mutation-producing megalencephaly, polymicrogyria, polydactyly, hydrocephalus (MPPH) syndrome; 3 with TSC mutations; 1 with megalencephaly capillary malformation syndrome; and 1 with hemimegalencephaly. Cardiac rhabdomyoma was present prenatally in all cases of TSC; mutation postaxial polydactyly accompanied megalencephaly capillary malformation and MPPH. Of 12 fetuses with small heads, 7 had TUBA1A mutations, 1 had a TUBB3 mutation, 2 had cobblestone lissencephaly postnatally with no genetic diagnosis, 1 had a PDHA1 mutation, and 1 had a fetal akinesia dyskinesia sequence with no pathogenic mutation on trio whole exome sequencing. One of the fetuses with a normal head size had an OPHN1 mutation with postnatal febrile seizures, and the other had peri-Sylvian polymicrogyria, seizures, and severe developmental delay but no explanatory mutation on whole exome sequencing. CONCLUSIONS: Fetal head size and extracranial prenatal sonographic findings can refine the phenotype and facilitate genetic diagnosis when ganglionic eminence abnormality is diagnosed with MR imaging.

Interobserver agreement and diagnostic performance of individual MRI criteria for diagnosis of placental adhesion disorders.

AIM: To assess the diagnostic accuracy of several criteria for the diagnosis of placental adhesion disorder (PAD) on magnetic resonance imaging (MRI) and to assess interobserver agreement and reader accuracy based on years of interpretive experience. MATERIALS AND METHODS: Blinded evaluation of the placental MRI studies of 28 randomly selected women, 18 with PADs and 10 without PADs, was undertaken by three radiologists with 10, 5, and 2 years' experience in placental MRI interpretation. The presence of placenta praevia, dark intraplacental bands, heterogeneity, uterine bulging, "shaggy dog" appearance of the uterine serosa, subjective impression of extraplacental invasion, and dark intraplacental bands on diffusion-weighted imaging were assessed. Placental histology was reviewed blinded to the original reports and to MRI interpretation and this, along with clinical information at the time of delivery, formed the reference standard. RESULTS: Dark intraplacental bands on T2-weighted imaging were the most sensitive and specific as well as the most agreed upon (kappa=0.7) criterion for PAD for the three readers. Assessment of uterine bulging (kappa=0.42) and placental heterogeneity (kappa=0.48) did not improve diagnostic accuracy. DWI improved sensitivity but decreased specificity for the least experienced reader and did not change sensitivity or specificity for the more experienced readers. CONCLUSION: Assessment of the placenta for dark bands is the most sensitive, specific, and reproducible criterion for diagnosis of PADs using MRI.

Paediatric CT dose: a multicentre audit of subspecialty practice in Australia and New Zealand.

OBJECTIVES: To evaluate paediatric CT dosimetry in Australia and New Zealand and calculate size-specific dose estimates (SSDEs) for chest and abdominal examinations. METHODS: Eight hospitals provided data from 12 CT systems for 1462 CTs in children aged 0-15. Imaging data were recorded for eight examinations: head (trauma, shunt), temporal bone, paranasal sinuses, chest (mass) and chest HRCT (high-resolution CT), and abdomen/pelvis (mass/inflammation). Dose data for cranial examinations were categorised by age and SSDEs by lateral dimension. Diagnostic reference ranges (DRRs) were defined by the 25th and 75th percentiles. Centralised image quality assessment was not undertaken. RESULTS: DRRs for 201 abdominopelvic SSDEs were: 2.8-4.7, 3.6-11.5, 8.5-15.0, 7.6-15, and 10.6-16.2 for the <15 cm, 15-19 cm, 20-24 cm, 25-29 cm and >30 cm groups, respectively. For 147 chest examinations using these body width categories, SSDE DRRs were 2.0-4.4, 3.3-7.9, 4.0-9.4, 4.5-12, and 6.5-12. Kilovoltage peak (kVp), but not AEC or IR, was associated with SSDE (parameter estimate [standard error]: 0.12 (0.03); p < 0.0001). CONCLUSIONS: Australian and New Zealand paediatric CT DRRs and abdominal SSDEs are comparable to international data. SSDEs for chest examinations are proposed. Dose variations could be reduced by adjusting kVp. KEY POINTS: • SSDEs can be calculated for all patients, CT systems, and practices • Kilovoltage peak (kVp) has the greatest association with dose in similar-sized patients • Paediatric DRRs for CT are now available for use internationally.

Early MRI in term infants with perinatal hypoxic-ischaemic brain injury: interobserver agreement and MRI predictors of outcome at 2 years.

AIM: To compare diffusion-weighted imaging (DWI) and non-DWI magnetic resonance imaging (MRI), proton MR spectroscopy (1H-MRS), and clinical biomarkers for prediction of 2 year developmental outcome in term infants with perinatal hypoxic-ischaemic encephalopathy (HIE). MATERIALS AND METHODS: Nineteen infants ≥36 weeks gestation with HIE were recruited and MRI performed day 3-7 (mean = 5). MRI was scored independently by three radiologists using a standardized scoring system. Lactate-to-N-acetylaspartate ratio (Lac:NAA) in the lentiform nucleus was calculated. Developmental assessment was performed at 2 years using the Bayley Scales of Infant and Toddler Development (BSID-III). Interobserver agreement about abnormality in 10 brain regions was measured. Univariate analysis was performed to determine variables associated with adverse outcome (i.e., death or Bayley score for any domain <70). RESULTS: Good interobserver agreement (kappa = 0.61-0.69) on scores for DWI was obtained for the cortex, putamen, and brainstem, but not for any region on non-DWI. A significant association was found between outcome and Lac:NAA (p < 0.003) and DWI scores for lentiform nucleus, thalamus, cortex, posterior limb of the internal capsule (PLIC), and paracentral white matter (p = 0.001-0.013), but for non-DWI score only in the vermis or brainstem. A combination of Lac:NAA ≥0.25 or DWI/apparent diffusion coefficient (ADC) signal abnormality in the PLIC had 100% specificity and sensitivity for poor outcome. CONCLUSION: Interobserver agreement for non-DWI performed during the first week is poor. Agreement by three radiologists about the presence of abnormal signal within the PLIC on ADC/DWI images or elevation of Lac:NAA above 0.25 improved sensitivity without reducing the prognostic specificity of MRS in the 19 patients, but this requires validation in a larger group of infants with HIE who have been treated with hypothermia.

Can an evidence-based guideline reduce unnecessary imaging of road trauma patients with cervical spine injury in the emergency department?

The aim of this study was to determine if an unvalidated imaging guideline can reduce the use of imaging in patients with cervical spine trauma. A non-randomized clinical trial using historical controls was conducted in the emergency department from October 2001 to September 2002. Following an education programme, which introduced the imaging guideline to clinicians, the use of guideline and imaging were measured. The guideline was also converted to decision-support software for use in the emergency department. Three hundred and fifty-three patients satisfied inclusion criteria during the study period and these were compared with 403 historical control subjects. No significant difference was found between the two groups for age, sex or fracture prevalence. A significant increase was observed during the study period in the proportion of patients who were managed without the use of any cervical spine imaging (21.25 vs 31.2%; P=0.03; 95% confidence interval, 3-13). There were no delayed diagnoses of cervical spine injury among those not imaged. It is feasible to disseminate and implement an evidence-based imaging guideline for patients with cervical spine trauma. The use of a computerized decision-support system can facilitate this and is associated with a safe reduction in the proportion of patients imaged.

Characteristics of breast carcinomas missed by screening radiologists.

PURPOSE: To determine whether breast cancers missed at screening mammography have distinguishing characteristics from those of detected cancers. MATERIALS AND METHODS: The mammograms of 146 women with mammographically identifiable breast cancer were viewed independently by two radiologists who were blinded as to whether the cancer had been missed or detected (group 1 lesions, missed cancers; group 2 lesions, detected cancers) at screening. The mammographic lesions were characterized as to location, size, density, type, and visibility on two views. RESULTS: A significant difference between missed and detected cancers was found for diameter (P = .03), number of views (P < .0017), and density (P = .0007). Stepwise multivariable logistic regression showed that density (P = .01) and the number of views (P = .03) but not diameter (P = .27) were independently significant in distinguishing the groups. No statistically significant difference was found between the two groups for lesion type (P = .32 for reader 1 and P = .27 for reader 2) or location (P = .86 for reader 1 and P > .96 for reader 2). CONCLUSION: Missed cancers were statistically significantly lower in density and more often seen on only one of two views than detected cancers.

Improving the diagnostic accuracy of MR in the detection of infraspinatus tendon injuries.

PURPOSE: Our goal was to determine the accuracy of MRI in the diagnosis of infraspinatus tendon injury and more specifically to determine if the antero-posterior extent of a rotator cuff tear is predictive of infraspinatus tearing. METHOD: The MR images of 41 shoulders with surgically proven supraspinatus tears at surgery were retrospectively reviewed. The following were assessed for each of the 41 studies: the number of oblique coronal images on which a tendon defect could be seen, the angle subtended by the tear on axial images (the rotator cuff "axial angle"), and the extent of signal abnormality on sagittal images. RESULTS: The rotator cuff axial angle was 75.6 degrees in patients with infraspinatus tendon tears (ITTs) versus 40 degrees in those without ITTs, and this difference was significant (p < 0.001, t = 3.06). The mean number of oblique coronal images (obtained with a 4 mm slice and 1 mm gap) showing signal abnormality was 5.4 in the ITT group versus 2.9 in those without ITTs, and this difference was also significant (p < 0.001, t = 4.45). The mean sagittal extent of the tendon abnormality was 24.6 mm in the ITT group and 11.6 mm in those without ITTs, but the difference was not significant (p > 0.05, t = 1.1364). CONCLUSION: The axial angle and the number of oblique coronal images in which signal abnormality was present were significantly related to a higher incidence of infraspinatus tears.

Patterns of contrast enhancement in the pediatric spine at MR imaging with single- and triple-dose gadolinium.

PURPOSE: To assess patterns of nerve root and spinal cord contrast enhancement in the pediatric spine at magnetic resonance (MR) imaging with single- and triple-dose gadolinium. MATERIALS AND METHODS: In three control patients with no suspected pathologic spinal condition and 19 patients with a suspected condition, spinal cords were evaluated prospectively for potential spread of tumor to cerebrospinal fluid ("drop metastases") (n = 18) or Guillain-Barré syndrome (n = 1). After enhancement with 0.1 mmol/kg gadolinium, patients without definite drop metastases (n = 8) received a booster of 0.2 mmol/kg gadolinium 30-40 minutes later; clinical follow-up was obtained 12 1/2 to 19 months later. RESULTS: Drop metastases appeared as nodular areas of enhancement in 11 patients. Vascular enhancement related to the spinal cord surface and emerging nerve roots was observed in images obtained in all control patients, as well as in patients with negative findings at lumbar puncture and at clinical or MR imaging follow-up examination (n = 6). Vascular and nerve root enhancement increased with triple-dose gadolinium and was greater in patients after radiation therapy (n = 17) than in control patients (n = 3). CONCLUSION: Use of triple-dose gadolinium did not result in detection of additional cases of drop metastases.

Colour-assisted compression ultrasound in the diagnosis of calf deep venous thrombosis.

OBJECTIVE: To determine sensitivity and specificity of colour-assisted compression ultrasound (CUS) in the diagnosis of deep venous thrombosis (DVT) isolated to the calf veins. DESIGN: Prospective comparison of CUS with contrast venography in patients undergoing both procedures, with blinded evaluation of results. SETTING: Alfred Hospital, Melbourne (an urban tertiary referral hospital), between November 1990 and May 1992. SUBJECTS: Patients presenting for contrast venography with signs or symptoms of lower limb DVT. OUTCOME MEASURES: Presence of DVT; technical adequacy of examination. RESULTS: 92 of 402 patients (104 limbs) were examined. DVT was detected by venography in 43 limbs and was isolated to the calf veins in 19. It was diagnosed by CUS for eight of these 19. Calf CUS was technically inadequate in 26 limbs. Sensitivity and specificity of CUS for isolated calf DVT were 67% (95% confidence interval [CI], 40%-94%) and 93% (95% CI, 83%-100%), respectively, when the CUS was adequate. The low sensitivity of CUS was related to small size of the thrombi, inadequate studies because of previous DVT or very swollen limbs and technical errors. CONCLUSION: CUS is accurate for detecting larger isolated calf DVT when the calf study is adequate. Including the calf veins as well as the femoropopliteal veins in the initial CUS examination for symptomatic suspected lower limb DVT may reduce the need for follow-up CUS.

Conspicuity of tumors of the head and neck on fat-suppressed MR images: T2-weighted fast-spin-echo versus contrast-enhanced T1-weighted conventional spin-echo sequences.

OBJECTIVE: The purpose of this study was to compare the conspicuity of tumors of the head and neck on MR images acquired with T2-weighted fat-suppressed fast-spin-echo and contrast-enhanced T1-weighted fat-suppressed conventional spin-echo sequences. MATERIALS AND METHODS: The MR images of 29 patients with 36 pathologically proved tumors of the head and neck were retrospectively analyzed. The conspicuity of these tumors was assessed on the T2-weighted sequence (4700/108 [TR/TE]) and on the contrast-enhanced T1-weighted sequence (500/16) with a 1.5-T system. Qualitative tumor-to-background contrast was graded separately against background muscle, fat, and mucosa (0 = not visualized, 1 = poorly visualized, 2 = fairly well visualized, 3 = well visualized), and the best overall sequence was noted for each tumor. Quantitative tumor-to-background ratios were measured for 10 of the tumors by using the same background markers. RESULTS: The mean overall qualitative tumor-to-background contrast grades for the T2-weighted sequence were tumor/muscle = 2.84, tumor/fat = 2.20, and tumor/mucosa = 1.23, and for the contrast-enhanced T1-weighted sequence, they were tumor/muscle = 2.02, tumor/fat = 1.58, and tumor/mucosa = 0.73. Overall, 86% of the tumors were better or equally well visualized on the T2-weighted images. The mean overall quantitative tumor-to-background ratios for the T2-weighted sequence were tumor/muscle = 7.93, tumor/fat = 3.34, and tumor/mucosa = 0.68, and for the contrast-enhanced T1-weighted sequence, they were tumor/muscle = 2.43, tumor/fat = 2.28, and tumor/mucosa = 0.85. CONCLUSION: The T2-weighted fat-suppressed fast-spin-echo sequence offers better contrast between tumors and adjacent muscle, fat, and mucosa than does the contrast-enhanced T1-weighted fat-suppressed spin-echo sequence and thus improves overall tumor conspicuity. In addition, the T2-weighted sequence does not require IV contrast material and can be performed more rapidly than can the contrast-enhanced T1-weighted sequence. The contrast-enhanced T1-weighted sequence may offer complementary information on the precise characterization of complex tumors and on the potential determination of tumor extent.

Comparison of ultrasound and blood pool scintigraphy in the diagnosis of lower limb deep venous thrombosis.

We report a prospective, blinded comparison of compression ultrasound (US) and Tc-99m erythrocyte-labelled venous blood pool scintigraphy (BPS) in patients presenting with symptoms of deep venous thrombosis (DVT). Contrast venography (CV) was used as the gold standard. Ninety-eight lower limbs of 76 patients were examined. DVT was present at CV in 38 of 98 limbs and was isolated to the calf veins in eight. Sensitivity and specificity of ultrasound for femoropopliteal thrombus were 81.5% and 96% and of venous blood pool scintigraphy were 55% and 96%. For deep venous thrombosis in the whole limb sensitivity and specificity of ultrasound were 74% and 90% and of venous blood pool scintigraphy were 61% and 88%. In the calf sensitivity and specificity of US were 61% and 94% and of venous blood pool scintigraphy were 61% and 89%. Excluding equivocal venous blood pool scintigraphy results, the predictive values of a positive and negative venous blood pool scintigraphy study for the whole limb were 84% and 86%. The predictive values of a positive and negative ultrasound where the examination was adequate were 82% and 86%. US is a more sensitive alternative to CV than BPS for femoropopliteal DVT. When neither US nor CV can be performed, BPS remains a useful initial test for DVT, provided it is unequivocally positive or negative.

Perimesencephalic subarachnoid haemorrhage: negative angiography and favourable prognosis.

The computed tomography (CT) scans of 110 consecutive patients who presented, over a 4.5-year period, following spontaneous subarachnoid haemorrhage (SAH), were reviewed. All 110 patients also had one or more 4-vessel digital subtraction cerebral angiograms. The CT scans were reviewed in each case without knowledge of the angiographic result. In nine patients (8%), SAH was confined to the perimesencephalic area, interpeduncular cistern and/or prepontine region at CT. All nine patients had at least two, and some as many as four, negative cerebral angiograms. Eighteen of the 110 patients (16%) ultimately had negative angiography. Hence, the patients with isolated perimesencephalic haemorrhage (PMH) accounted for 50% of the negative angiograms. There was a significant association between isolated PMH and negative angiography (chi 2 = 50.1, P < 0.005). The specificity of PMH for negative angiography was 100% (95% confidence interval (CI) = 97-100%) and the sensitivity of PMH for a negative study was 50% (95% CI = 16-84%). Six of the 110 patients had basilar artery aneurysms demonstrated angiographically as the cause of their SAH but none of these six had isolated PMH at CT. All patients with isolated PMH were alive and well at follow up and none had suffered repeat SAH or vasospasm-related ischaemic cerebral injury. Perimesencephalic haemorrhage should be distinguished from SAH in general, because of the good prognosis associated with it and the doubtful need for repeat cerebral angiography after an initial negative study.

Pulmonary arteriovenous malformations: pathology, clinical features and treatment with balloon and coil occlusion.

This paper discusses the cases of 5 patients who have had therapeutic occlusion of their pulmonary arteriovenous malformations (PAVM) performed radiologically at Alfred Hospital in the past 4 years. The salient pathological, clinical and radiological features of PAVM are also presented.

Interventricular neurocytoma: radiologic features and review of the literature.

Intraventricular neurocytoma (IN), a recently recognized, benign cerebral tumor of young adults, can be confused with oligodendroglioma and other neoplasms. The authors compared the radiologic features of six pathologically confirmed cases of IN with those of 26 previously reported cases. The presenting symptoms were headache (62%), raised intracranial pressure (41%), and seizures (12%). Radiologically, the tumor frequently demonstrated a characteristic attachment to the septum pellicidum and confinement to the lateral and third ventricles. Calcification, which is common in IN and an important diagnostic feature, was seen to best advantage on computed tomographic (CT) scans. The results indicate that IN can be suggested radiologically on the basis of its CT appearance and should be included in the pathologic differential diagnosis of intraventricular tumors.