Multi-modality imaging review of congenital abnormalities of kidney and upper urinary tract

Congenital abnormalities of the kidney and urinary tract (CAKUT) include a wide range of abnormalities ranging from asymptomatic ectopic kidneys to life threatening renal agenesis (bilateral). Many of them are detected in the antenatal or immediate postnatal with a significant proportion identified in the adult population with varying degree of severity. CAKUT can be classified on embryological basis in to abnormalities in the renal parenchymal development, aberrant embryonic migration and abnormalities of the collecting system. Renal parenchymal abnormalities include multi cystic dysplastic kidneys, renal hypoplasia, number (agenesis or supernumerary), shape and cystic renal diseases. Aberrant embryonic migration encompasses abnormal location and fusion anomalies. Collecting system abnormalities include duplex kidneys and Pelvi ureteric junction obstruction. Ultrasonography (US) is typically the first imaging performed as it is easily available, non-invasive and radiation free used both antenatally and postnatally. Computed tomography (CT) and magnetic resonance imaging (MRI) are useful to confirm the ultrasound detected abnormality, detection of complex malformations, demonstration of collecting system and vascular anatomy and more importantly for early detection of complications like renal calculi, infection and malignancies. As CAKUT are one of the leading causes of end stage renal disease, it is important for the radiologists to be familiar with the varying imaging appearances of CAKUT on US, CT and MRI, thereby helping in prompt diagnosis and optimal management.

Three-dimensional radiation dosimetry using polymer gel and solid radiochromic polymer: From basics to clinical applications

Accurate dose measurement tools are needed to evaluate the radiation dose delivered to patients by using modern and sophisticated radiation therapy techniques. However, the adequate tools which enable us to directly measure the dose distributions in three-dimensional (3D) space are not commonly available. One such 3D dose measurement device is the polymer-based dosimeter, which changes the material property in response to radiation. These are available in the gel form as polymer gel dosimeter (PGD) and ferrous gel dosimeter (FGD) and in the solid form as solid plastic dosimeter (SPD). Those are made of a continuous uniform medium which polymerizes upon irradiation. Hence, the intrinsic spatial resolution of those dosimeters is very high, and it is only limited by the method by which one converts the dose information recorded by the medium to the absorbed dose. The current standard methods of the dose quantification are magnetic resonance imaging, optical computed tomography, and X-ray computed tomography. In particular, magnetic resonance imaging is well established as a method for obtaining clinically relevant dosimetric data by PGD and FGD. Despite the likely possibility of doing 3D dosimetry by PGD, FGD or SPD, the tools are still lacking wider usages for clinical applications. In this review article, we summarize the current status of PGD, FGD, and SPD and discuss the issue faced by these for wider acceptance in radiation oncology clinic and propose some directions for future development.

Feasibility study of computed vs measured high b-value (1400 s/mm²) diffusion-weighted MR images of the prostate

AIM: To evaluate the impact of computed b = 1400 s/mm² (C-b1400) vs measured b = 1400 s/mm² (M-b1400) diffusion-weighted images (DWI) on lesion detection rate, image quality and quality of lesion demarcation using a modern 3T-MR system based on a small-field-of-view sequence (sFOV).

METHODS: Thirty patients (PSA: 9.5 ± 8.7 ng/mL; 68 ± 12 years) referred for magnetic resonance imaging (MRI) of the prostate were enrolled in this study. All measurements were performed on a 3T MR system. For DWI, a single-shot EPI diffusion sequence (b = 0, 100, 400, 800 s/mm²) was utilized. C-b1400 was calculated voxelwise from the ADC and diffusion images. Additionally, M-b1400 was acquired for evaluation and comparison. Lesion detection rate and maximum lesion diameters were obtained and compared. Image quality and quality of lesion demarcation were rated according to a 5-point Likert-type scale. Ratios of lesion-to-bladder as well as prostate-to-bladder signal intensity (SI) were calculated to estimate the signal-to-noise-ratio (SNR).

RESULTS: Twenty-four lesions were detected on M-b1400 images and compared to C-b1400 images. C-b1400 detected three additional cancer suspicious lesions. Overall image quality was rated significantly better and SI ratios were significantly higher on C-b1400 (2.3 ± 0.8 vs 3.1 ± 1.0, P < 0.001; 5.6 ± 1.8 vs 2.8 ± 0.9, P < 0.001). Comparison of lesion size showed no significant differences between C- and M-b1400 (P = 0.22).

CONCLUSION: Combination of a high b-value extrapolation and sFOV may contribute to increase diagnostic accuracy of DWI without an increase of acquisition time, which may be useful to guide targeted prostate biopsies and to improve quality of multiparametric MRI (mMRI) especially under economical aspects in a private practice setting.

Magnetic resonance imaging staging of nasopharyngeal carcinoma in the head and neck

Magnetic resonance imaging (MRI) is the modality of choice for staging nasopharyngeal carcinoma in the head and neck. This article will review the patterns of primary and nodal spread on MRI with reference to the latest 7th edition of the International Union Against Cancer/American Joint Committee on Cancer staging system.

Endovascular management of visceral artery aneurysms: When to watch, when to intervene?

Visceral artery aneurysms (VAA) include splanchnic and renal artery aneurysms. They represent a rare clinical entity, although their detection is rising due to an increased use of cross-sectional imaging. Rupture is the most devastating complication, and is associated with a high morbidity and mortality. In addition, increased percutaneous endovascular interventions have raised the incidence of iatrogenic visceral artery pseudoaneurysms (VAPAs). For this reason, elective repair is preferable in the appropriately chosen patient. Controversy still exists regarding their treatment. Over the past decade, there has been steady increase in the utilization of minimally invasive, non-operative interventions, for vascular aneurysmal disease. All VAAs and VAPAs can technically be fixed by endovascular techniques but that does not mean they should. These catheter-based techniques constitute an excellent approach in the elective setting. However, in the emergent setting it may carry a higher morbidity and mortality. The decision for intervention has to take into account the size and the natural history of the lesion, the risk of rupture, which is high during pregnancy, and the relative risk of surgical or radiological intervention. For splanchnic artery aneurysms, we should recognize that we are not, in reality, well informed about their natural history. For most asymptomatic aneurysms, expectant treatment is acceptable. For large, symptomatic or aneurysms with a high risk of rupture, endovascular treatment has become the first-line therapy. Treatment of VAPAs is always mandatory because of the high risk of rupture. We present our point of view on interventional radiology in the splanchnic arteries, focusing on what has been achieved and the remaining challenges.

Lymph node imaging in initial staging of prostate cancer: An overview and update

Accurate nodal staging at the time of diagnosis of prostate cancer is crucial in determining a treatment plan for the patient. Pelvic lymph node dissection is the most reliable method, but is less than perfect and has increased morbidity. Cross sectional imaging with computed tomography (CT) and magnetic resonance imaging (MRI) are non-invasive tools that rely on morphologic characteristics such as shape and size of the lymph nodes. However, lymph nodes harboring metastatic disease may be normal sized and non-metastatic lymph nodes may be enlarged due to reactive hyperplasia. The optimal strategy for preoperative staging remains a topic of ongoing research. Advanced imaging techniques to assess lymph nodes in the setting of prostate cancer utilizing novel MRI contrast agents as well as positron emission tomography (PET) tracers have been developed and continue to be studied. Magnetic resonance lymphography utilizing ultra-small super paramagnetic iron oxide has shown promising results in detection of metastatic lymph nodes. Combining MRL with diffusion-weighted imaging may also improve accuracy. Considerable efforts are being made to develop effective PET radiotracers that are performed using hybrid-imaging systems that combine PET with CT or MRI. PET tracers that will be reviewed in this article include [¹⁸F]fluoro-D-glucose, sodium [¹⁸F]fluoride, [¹⁸F]choline, [¹¹C]choline, prostate specific membrane antigen binding ligands, [¹¹C]acetate, [¹⁸F]fluciclovine, gastrin releasing peptide receptor ligands, and androgen binding receptors. This article will review these advanced imaging modalities and ability to detect prostate cancer metastasis to lymph nodes. While more research is needed, these novel techniques to image lymph nodes in the setting of prostate cancer show a promising future in improving initial lymph node staging.

Chest radiographic and computed tomographic manifestations in allergic bronchopulmonary aspergillosis

AIM: To investigate the chest radiographic and high resolution computed tomography (HRCT) chest manifestations in glucocorticoid-naïve allergic bronchopulmonary aspergillosis (ABPA) patients.

METHODS: This is a prospective observational study and includes 60 consecutive glucocorticoid-naïve patients with ABPA who underwent chest radiography and HRCT of the chest (1.25 mm every 10 mm) in the routine diagnostic workup for ABPA.

RESULTS: Chest radiographs were normal in 50% of cases. Of the remainder, most patients demonstrated permanent findings in the form of parallel line and ring shadows suggesting bronchiectasis. Consolidation was detected in 17 cases but in the majority, the corresponding HRCT chest scan showed mucus-filled bronchiectatic cavities. Chest HRCT was normal in 22 patients, while central bronchiectasis (CB) was demonstrated in the remaining 38 patients. Bronchiectasis extended to the periphery in 33%-43% depending on the criteria used for defining CB. The other findings observed on HRCT were mucoid impaction, centrilobular nodules and high-attenuation mucus in decreasing order of frequency.

CONCLUSION: Patients with ABPA can present with normal HRCT chest scans. Central bronchiectasis cannot be considered a characteristic feature of ABPA as peripheral bronchiectasis is commonly observed. Consolidation is an uncommon finding in ABPA.

Diffusion-weighted magnetic resonance imaging in cancer: Reported apparent diffusion coefficients, in-vitro and in-vivo reproducibility

There is considerable disparity in the published apparent diffusion coefficient (ADC) values across different anatomies. Institutions are increasingly assessing repeatability and reproducibility of the derived ADC to determine its variation, which could potentially be used as an indicator in determining tumour aggressiveness or assessing tumour response. In this manuscript, a review of selected articles published to date in healthy extra-cranial body diffusion-weighted magnetic resonance imaging is presented, detailing reported ADC values and discussing their variation across different studies. In total 115 studies were selected including 28 for liver parenchyma, 15 for kidney (renal parenchyma), 14 for spleen, 13 for pancreatic body, 6 for gallbladder, 13 for prostate, 13 for uterus (endometrium, myometrium, cervix) and 13 for fibroglandular breast tissue. Median ADC values in selected studies were found to be 1.28 × 10(-3) mm(2)/s in liver, 1.94 × 10(-3) mm(2)/s in kidney, 1.60 × 10(-3) mm(2)/s in pancreatic body, 0.85 × 10(-3) mm(2)/s in spleen, 2.73 × 10(-3) mm(2)/s in gallbladder, 1.64 × 10(-3) mm(2)/s and 1.31 × 10(-3) mm(2)/s in prostate peripheral zone and central gland respectively (combined median value of 1.54×10(-3) mm(2)/s), 1.44 × 10(-3) mm(2)/s in endometrium, 1.53 × 10(-3) mm(2)/s in myometrium, 1.71 × 10(-3) mm(2)/s in cervix and 1.92 × 10(-3) mm(2)/s in breast. In addition, six phantom studies and thirteen in vivo studies were summarized to compare repeatability and reproducibility of the measured ADC. All selected phantom studies demonstrated lower intra-scanner and inter-scanner variation compared to in vivo studies. Based on the findings of this manuscript, it is recommended that protocols need to be optimised for the body part studied and that system-induced variability must be established using a standardized phantom in any clinical study. Reproducibility of the measured ADC must also be assessed in a volunteer population, as variations are far more significant in vivo compared with phantom studies.

Systemic air embolism after transthoracic lung biopsy: A case report and review of literature

Computed tomography (CT)-guided lung biopsy is a common diagnostic procedure that is associated with various complications, including pneumothorax, hemoptysis and parenchymal hemorrhage. Systemic air embolism is a very rare (0.07%) but potentially life-threatening complication. We report a fatal case of air embolism to the cerebral and coronary arteries confirmed by head and chest CT, followed by a review of the literature.

Multi-detector CT features of acute intestinal ischemia and their prognostic correlations

Acute intestinal ischemia is an abdominal emergency occurring in nearly 1% of patients presenting with acute abdomen. The causes can be occlusive or non occlusive. Early diagnosis is important to improve survival rates. In most cases of late or missed diagnosis, the mortality rate from intestinal infarction is very high, with a reported value ranging from 60% to 90%. Multi-detector computed tomography (MDCT) is a fundamental imaging technique that must be promptly performed in all patients with suspected bowel ischemia. Thanks to the new dedicated reconstruction program, its diagnostic potential is much improved compared to the past and currently it is superior to that of any other noninvasive technique. The increased spatial and temporal resolution, high-quality multi-planar reconstructions, maximum intensity projections, vessel probe, surface-shaded volume rending and tissue transition projections make MDCT the gold standard for the diagnosis of intestinal ischemia, with reported sensitivity, specificity, positive and negative predictive values of 64%-93%, 92%-100%, 90%-100% and 94%-98%, respectively. MDCT contributes to appropriate treatment planning and provides important prognostic information thanks to its ability to define the nature and extent of the disease. The purpose of this review is to examine the diagnostic and prognostic role of MDCT in bowel ischemia with special regard to the state of art new reconstruction software.

Ultrasonography of normal and abnormal appendix in children

Appendicitis is the most common acute surgical emergency of childhood. Since the original report by Puylaert in 1986, the use of ultrasonography in the diagnosis of appendicitis has been the subject of considerable study. Among the reported diagnostic criteria, the maximal outer diameter (MOD) of the appendix is accepted as the one of the most reliable criteria used to differentiate between a normal appendix and acute appendicitis. However, MOD measurement is subject to inaccuracies because luminal distention by non-compressible, non-inflammatory material such as fecal material, or increased maximal mural thickness due to reactive mucosal lymphoid hyperplasia, or a medical cause due to a generalized gastrointestinal disease, such as Crohn’s disease, can cause the measurement to exceed the upper limits of normality. The aim of this article is to introduce the spectrum of ultrasonographic findings in the normal and abnormal appendix and eventually to reduce unnecessary surgery in children.

Diffusion weighted imaging for the detection and evaluation of cholesteatoma

Cholesteatoma is a collection of keratinous debris and stratified squamous epithelium. It is trapped in the middle ear and can lead to bony erosion. The disease is treated surgically often followed by a second-look procedure to check for residual tissue or recurrence. Cholesteatoma has specific signal-intensity characteristics on magnetic resonance imaging with very high signal intensity on diffusion weighted imaging (DWI). Various DWI techniques exist: Echo-planar imaging (EPI)-based and non-EPI-based techniques as well as new approaches like multi-shot EPI DWI. This article summarizes all techniques, discusses the significance in detecting cholesteatoma and mentions actual studies. Further recommendations for daily clinical practise are provided.

Is ARFI elastography reliable for predicting fibrosis severity in chronic HCV hepatitis?

AIM

To determine whether acoustic radiation force impulse (ARFI) elastography is a reliable method for predicting fibrosis severity in patients with chronic hepatitis C virus (HCV) hepatitis.

METHODS

We performed a multicenter study including 274 subjects with HCV chronic hepatitis in which we compared ARFI with liver biopsy (LB). In each patient we performed LB (evaluated according to the Metavir score) and ARFI measurements (using a Siemens Acuson S2000™ ultrasound system: 10 valid measurements were performed and median values were calculated and expressed in meters/second (m/s).

RESULTS

A direct, strong, correlation (Spearman r = 0.707) was found between ARFI measurements and fibrosis (P < 0.0001). For predicting the presence of fibrosis (F ≥ 1 Metavir), significant fibrosis (F ≥ 2), severe fibrosis (F ≥ 3) and cirrhosis (F = 4), the cut-off values of 1.19, 1.21, 1.58 and 1.82 m/s were determined, respectively, liver stiffness measurements had 73%, 84%, 84% and 91% Se respectively; 93%, 91%, 94%, 90% Sp, respectively; with AUROCs of 0.880, 0.893, 0.908 and 0.937, respectively.

CONCLUSION

ARFI measurement is a reliable method for predicting the severity of fibrosis in HCV patients.

Contrast-enhanced ultrasound in the biliary system: Potential uses and indications

Conventional ultrasound (US) is the first-line imaging investigation for biliary diseases. However, it is lack of the ability to depict the microcirculation of some lesions which may lead to failure in diagnosis for some biliary diseases. The use of contrast-enhanced US (CEUS) has reached the field of bile duct disease in recent years and promising results have been achieved. In this review, the methodology, image interpretation, enhancement pattern, clinical usefulness, and indications for CEUS in the biliary system are summarized. CEUS may be indicated in the biliary system under the following circumstances: (1) Where there is a need to make a characterization of intrahepatic cholangiocarcinoma (ICC); (2) For differentiation diagnosis between ICC and other tumors (i.e. hepatocellular carcinoma or liver metastasis) or infectious diseases; (3) For differentiation diagnosis between biliary cystadenoma and biliary cystadenocarcinoma; (4) To detect malignant change in Caroli’s disease; (5) To depict the extent of Klatskin’s tumor with greater clarity; (6) To make a distinction between gallbladder cholesterol polyp, adenoma and polypoid cancer; (7) To make a distinction between chronic cholecystitis with thickened wall and gallbladder cancer; (8) For differentiation diagnosis between motionless sludge and gallbladder cancer; (9) For differentiation diagnosis between common bile duct cancer and sludge or stone without acoustic shadowing; and (10) In patients who are suspected of having a drop of their percutaneous transhepatic cholangiodrainage tube, US contrast agent can be administered to through the tube detect the site of the tube.

ARFI elastography for the evaluation of diffuse thyroid gland pathology: Preliminary results

AIM

To assess whether acoustic radiation force impulse (ARFI) elastography can differentiate normal from pathological thyroid parenchyma.

METHODS

We evaluated 136 subjects (mean age 45.8 ± 15.6 years, 106 women and 30 men): 44 (32.3%) without thyroid pathology, 48 (35.3%) with Basedow-Graves' disease (GD), 37 (27.2%) with chronic autoimmune thyroiditis (CAT; diagnosed by specific tests), 4 (2.9%) with diffuse thyroid goiter and 3 (2.2%) cases with thyroid pathology induced by amiodarone. In all patients, 10 elastographic measurements were made in the right thyroid lobe and 10 in the left thyroid lobe, using a 1-4.5 MHZ convex probe and a 4-9 MHz linear probe, respectively. Median values were calculated for thyroid stiffness and expressed in meters/second (m/s).

RESULTS

Thyroid stiffness (TS) assessed by means of ARFI in healthy subjects (2 ± 0.40 m/s) was significantly lower than in GD (2.67 ± 0.53 m/s) (P < 0.0001) and CAT patients (2.43 ± 0.58 m/s) (P = 0.0002), but the differences were not significant between GD vs CAT patients (P = 0.053). The optimal cut-off value for the prediction of diffuse thyroid pathology was 2.36 m/s. For this cut-off value, TS had 62.5% sensitivity, 79.5% specificity, 87.6% predictive positive value, 55.5% negative predictive value and 72.7% accuracy for the presence of diffuse thyroid gland pathology (AUROC = 0.804). There were no significant differences between the TS values obtained with linear vs convex probes and when 5 vs 10 measurements were taken in each lobe (median values).

CONCLUSION

ARFI seems to be a useful method for the assessment of diffuse thyroid gland pathology.

Asymmetrically hypointense veins on T2*w imaging and susceptibility-weighted imaging in ischemic stroke

AIM: To review the literature on the assessment of venous vessels to estimate the penumbra on T2*w imaging and susceptibility-weighted imaging (SWI).

METHODS: Literature that reported on the assessment of penumbra by T2*w imaging or SWI and used a validation method was included. PubMed and relevant stroke and magnetic resonance imaging (MRI) related conference abstracts were searched. Abstracts that had overlapping content with full text articles were excluded. The retrieved literature was scanned for further relevant references. Only clinical literature published in English was considered, patients with Moya-Moya syndrome were disregarded. Data is given as cumulative absolute and relative values, ranges are given where appropriate.

RESULTS: Forty-three publications including 1145 patients could be identified. T2*w imaging was used in 16 publications (627 patients), SWI in 26 publications (453 patients). Only one publication used both (65 patients). The cumulative presence of hypointense vessel sign was 54% (range 32%-100%) for T2* (668 patients) and 81% (range 34%-100%) for SWI (334 patients). There was rare mentioning of interrater agreement (6 publications, 210 patients) and reliability (1 publication, 20 patients) but the numbers reported ranged from good to excellent. In most publications (n = 22) perfusion MRI was used as a validation method (617 patients). More patients were scanned in the subacute than in the acute phase (596 patients vs 320 patients). Clinical outcome was reported in 13 publications (521 patients) but was not consistent.

CONCLUSION: The low presence of vessels signs on T2*w imaging makes SWI much more promising. More research is needed to obtain formal validation and quantification.

Applications of multi-nuclear magnetic resonance spectroscopy at 7T

AIM

To discuss the advantages of ultra-high field (7T) for (1)H and (13)C magnetic resonance spectroscopy (MRS) studies of metabolism.

METHODS

Measurements of brain metabolites were made at both 3 and 7T using (1)H MRS. Measurements of glycogen and lipids in muscle were measured using (13)C and (1)H MRS respectively.

RESULTS

In the brain, increased signal-to-noise ratio (SNR) and dispersion allows spectral separation of the amino-acids glutamate, glutamine and γ-aminobutyric acid (GABA), without the need for sophisticated editing sequences. Improved quantification of these metabolites is demonstrated at 7T relative to 3T. SNR was 36% higher, and measurement repeatability (% coefficients of variation) was 4%, 10% and 10% at 7T, vs 8%, 29% and 21% at 3T for glutamate, glutamine and GABA respectively. Measurements at 7T were used to compare metabolite levels in the anterior cingulate cortex (ACC) and insula. Creatine and glutamate levels were found to be significantly higher in the insula compared to the ACC (P < 0.05). In muscle, the increased SNR and spectral resolution at 7T enables interleaved studies of glycogen ((13)C) and intra-myocellular lipid (IMCL) and extra-myocellular lipid (EMCL) ((1)H) following exercise and re-feeding. Glycogen levels were significantly decreased following exercise (-28% at 50% VO(2) max; -58% at 75% VO(2) max). Interestingly, levels of glycogen in the hamstrings followed those in the quadriceps, despite reduce exercise loading. No changes in IMCL and EMCL were found in the study.

CONCLUSION

The demonstrated improvements in brain and muscle MRS measurements at 7T will increase the potential for use in investigating human metabolism and changes due to pathologies.

Middle cerebellar peduncles: Magnetic resonance imaging and pathophysiologic correlate

We describe common and less common diseases that can cause magnetic resonance signal abnormalities of middle cerebellar peduncles (MCP), offering a systematic approach correlating imaging findings with clinical clues and pathologic mechanisms. Myelin abnormalities, different types of edema or neurodegenerative processes, can cause areas of abnormal T2 signal, variable enhancement, and patterns of diffusivity of MCP. Pathologies such as demyelinating disorders or certain neurodegenerative entities (e.g., multiple system atrophy or fragile X-associated tremor-ataxia syndrome) appear to have predilection for MCP. Careful evaluation of concomitant imaging findings in the brain or brainstem; and focused correlation with key clinical findings such as immunosuppression for progressive multifocal leukoencephalopahty; hypertension, post-transplant status or high dose chemotherapy for posterior reversible encephalopathy; electrolyte disorders for myelinolysis or suspected toxic-drug related encephalopathy; would yield an appropriate and accurate differential diagnosis in the majority of cases.

Enhanced myocardial fluorodeoxyglucose uptake following Adriamycin-based therapy: Evidence of early chemotherapeutic cardiotoxicity?

AIM: To analyze changes in myocardial glucose metabolism using fluorodeoxyglucose (FDG)-positron emission tomography (PET) in patients treated with adriamycin and to investigate the clinical significance of these changes.

METHODS: Considering that FDG-PET scanning has the ability to show changes in glucose metabolism in the myocardium, we retrospectively analyzed the FDG-PET studies of 18 lymphoma patients treated with adriamycin-based chemotherapy in both the pre- and post-therapy setting. Cardiac contractile parameters such as left ventricular ejection fraction were not available for correlation in all patients due to the short duration and the level of cumulative dose administered in these patients during the time of the follow-up FDG-PET study. The change in myocardial glucose utilization was estimated by change in standard uptake values (SUV) in the myocardium.

RESULTS: We observed a significant change in SUVmean values in the myocardium (defined as more than ± 20% change in cardiac SUVmean between pre- and post-chemotherapy PET) in 12 patients, whereas 6 patients did not show any significant cardiac FDG uptake in both pre- and post-therapy PET scans. Patients were divided into three groups based on the changes observed in myocardial tracer uptake on the follow-up ¹⁸F-FDG-PET study. Group A (n = 8): showed an increase in cardiac ¹⁸F-FDG uptake in the post-therapy scan compared to the baseline scan carried out prior to starting adriamycin-based chemotherapy. Group B (n = 6): showed no significant cardiac ¹⁸F-FDG uptake in post-therapy and baseline PET scans, and group C (n = 4): showed a fall in cardiac ¹⁸F-FDG uptake in the post-therapy scan compared to the baseline scan. Mean cumulative adriamycin dose (in mg/m²) received during the time of the follow-up FDG-PET study was 256.25, 250 and 137.5, respectively.

CONCLUSION: Our study shows three different trends in the change in myocardial glucose metabolism in patients undergoing adriamycin-based chemotherapy. A further prospective study with prolonged follow-up of ventricular function is warranted to explore the significance of enhanced FDG uptake as a marker of early identification of adriamycin-induced cardiotoxicity.

Use of cone beam computed tomography in periodontology

Diagnosis of periodontal disease mainly depends on clinical signs and symptoms. However, in the case of bone destruction, radiographs are valuable diagnostic tools as an adjunct to the clinical examination. Two dimensional periapical and panoramic radiographs are routinely used for diagnosing periodontal bone levels. In two dimensional imaging, evaluation of bone craters, lamina dura and periodontal bone level is limited by projection geometry and superpositions of adjacent anatomical structures. Those limitations of 2D radiographs can be eliminated by three-dimensional imaging techniques such as computed tomography. Cone beam computed tomography (CBCT) generates 3D volumetric images and is also commonly used in dentistry. All CBCT units provide axial, coronal and sagittal multi-planar reconstructed images without magnification. Also, panoramic images without distortion and magnification can be generated with curved planar reformation. CBCT displays 3D images that are necessary for the diagnosis of intra bony defects, furcation involvements and buccal/lingual bone destructions. CBCT applications provide obvious benefits in periodontics, however; it should be used only in correct indications considering the necessity and the potential hazards of the examination.

Cerebellum and neurodegenerative diseases: Beyond conventional magnetic resonance imaging

The cerebellum plays a key role in movement control and in cognition and cerebellar involvement is described in several neurodegenerative diseases. While conventional magnetic resonance imaging (MRI) is widely used for brain and cerebellar morphologic evaluation, advanced MRI techniques allow the investigation of cerebellar microstructural and functional characteristics. Volumetry, voxel-based morphometry, diffusion MRI based fiber tractography, resting state and task related functional MRI, perfusion, and proton MR spectroscopy are among the most common techniques applied to the study of cerebellum. In the present review, after providing a brief description of each technique’s advantages and limitations, we focus on their application to the study of cerebellar injury in major neurodegenerative diseases, such as multiple sclerosis, Parkinson’s and Alzheimer’s disease and hereditary ataxia. A brief introduction to the pathological substrate of cerebellar involvement is provided for each disease, followed by the review of MRI studies exploring structural and functional cerebellar abnormalities and by a discussion of the clinical relevance of MRI measures of cerebellar damage in terms of both clinical status and cognitive performance.

Contrast enhanced ultrasound of hepatocellular carcinoma

Sonazoid (Daiichi Sankyo, Tokyo, Japan), a second-generation of a lipid-stabilized suspension of a perfluorobutane gas microbubble contrast agent, has been used clinically in patients with liver tumors and for harmonic gray-scale ultrasonography (US) in Japan since January 2007. Sonazoid-enhanced US has two phases of contrast enhancement: vascular and late. In the late phase of Sonazoid-enhanced US, we scanned the whole liver using this modality at a low mechanical index (MI) without destroying the microbubbles, and this method allows detection of small viable hepatocellular carcinoma (HCC) lesions which cannot be detected by conventional US as perfusion defects in the late phase. Re-injection of Sonazoid into an HCC lesion which previously showed a perfusion defect in the late phase is useful for confirming blood flow into the defects. High MI intermittent imaging at 2 frames per second in the late phase is also helpful in differentiation between necrosis and viable hypervascular HCC lesions. Sonazoid-enhanced US by the coded harmonic angio mode at a high MI not only allows clear observation of tumor vessels and tumor enhancement, but also permits automatic scanning with Sonazoid-enhanced three dimensional (3D) US. Fusion images combining US with contrast-enhanced CT or contrast-enhanced MRI have made it easy to detect typical or atypical HCC lesions. By these methods, Sonazoid-enhanced US can characterize liver tumors, grade HCC lesions histologically, recognize HCC dedifferentiation, evaluate the efficacy of ablation therapy or transcatheter arterial embolization, and guide ablation therapy for unresectable HCC. This article reviews the current developments and applications of Sonazoid-enhanced US and Sonazoid-enhanced 3D US for diagnosing and treating hepatic lesions, especially HCC.

Partial volume effect modeling for segmentation and tissue classification of brain magnetic resonance images: A review

Quantitative analysis of magnetic resonance (MR) brain images are facilitated by the development of automated segmentation algorithms. A single image voxel may contain of several types of tissues due to the finite spatial resolution of the imaging device. This phenomenon, termed partial volume effect (PVE), complicates the segmentation process, and, due to the complexity of human brain anatomy, the PVE is an important factor for accurate brain structure quantification. Partial volume estimation refers to a generalized segmentation task where the amount of each tissue type within each voxel is solved. This review aims to provide a systematic, tutorial-like overview and categorization of methods for partial volume estimation in brain MRI. The review concentrates on the statistically based approaches for partial volume estimation and also explains differences to other, similar image segmentation approaches.

Imaging appearance of bone tumors of the maxillofacial region

This paper reviews the imaging appearance of benign and malignant bone tumors of the maxillofacial region. A benign bone tumor commonly appears as a well circumscribed lesion. The matrix of the tumor may be calcified or sclerotic. Malignancies often display aggressive characteristics such as cortical breakthrough, bone destruction, a permeative pattern and associated soft-tissue masses. Computed tomography scan is an excellent imaging modality for accurate localization of the lesion, characterization of the tumor matrix and detection of associated osseous changes such as bone remodeling, destruction or periosteal reaction. Magnetic resonance imaging is of limited value in the evaluation of maxillofacial bone tumors.

Imaging in male-factor obstructive infertility

The main purpose of imaging evaluation in male infertility is to identify and treat correctable causes of infertility, such as obstruction of the seminal tract. Various imaging modalities are available to evaluate men with obstructive infertility including scrotal ultrasonography, transrectal ultrasound (TRUS), vasography, magnetic resonance imaging, seminal vesicle aspiration, seminal tract washout, and seminal vesiculography. To date the most reliable and accurate diagnostic technique for obstructive infertility is unclear. In this review article, we report the role of these modalities in diagnosis of obstructive infertility. Scrotal sonography is the initial modality, and if patient results indicate non obstructive azoospermia as varicocele or testicular pathology they will be treated according to standard protocols for management of these pathologies. If the patient findings indicate proximal obstructive azoospermia, they can be managed by vasoepididymostomy. If the scrotal ultrasound is normal, TRUS is the second imaging modality. Accordingly, they are classified into patients with criteria of obstructive infertility without urogenital cysts where TRUS-guided aspiration and seminal vesiculography can be performed and transurethral resection of the ejaculatory ducts (TURED) will be the management of choice. In patients with urogenital cyst, TRUS-guided cyst aspiration and opacification are performed. If the cyst is communicating with the seminal tract, management will be transurethral incision of the cyst. If the cyst is not in communication, the obstruction may be relieved after cyst aspiration. If the obstruction is not relieved, TURED will be the management of choice. Sperm harvested during aspiration may be stored and used in assisted reproduction techniques. If the results of TRUS are inconclusive or doubtful, endorectal magnetic resonance imaging should be performed to serve as a “detailed map” for guiding corrective operative interventions.